communications to the fourth world congress of science and football

Journal of Sports Sciences, 1999, 17, 807± 840

Journal of Sports Sciences ISSN 0264-041 4 print/ISSN 1466-447 X online Ó Taylor & Francis Ltd

CONFERENCE COMMUNICATIONS

Communications to the Fourth World Congress ofScience and Football

Held at the University of Technology, Sydney, NSW, Australia, 22± 26 Februar y 1999

PART I: PHYSIOLOGY AND KINANTHROPOM ETRY

Echocardiographic assessm ent of elite Saudi soccer

players

H.M. Al-Hazzaa and A.C. Chukwuemeka

Exercise Physiology Laboratory, King Saud University and Sports

Medicine Hospital, GPYW, Riyadh, Saudi Arabia

Much physiological and cardiographic data exist for elite

soccer players worldwide; however, there are few data for elite

Saudi soccer players. The aims of this study were to record

the echocardiographic measurements on 23 members of the

Saudi national soccer team and to correlate these W ndings with

maximal oxygen uptake (VÇ O2max).

The players’ mean (± s) age, body mass, height and percent

body fat were 25.2 ± 3.3 years, 73.1 ± 6.8 kg, 177 ± 6 cm and

12.3 ± 2.7% respectively. The players’ cardiac dimensions were

measured by M-mode echocardiography at end-diastole and

VÇ O 2max was assessed by open-circuit spirometry during tread-

mill running. The results, normalized to body surface area,

were as follows: left ventricular posterior wall, 5.30 ± 0.77

mm ´m - 2; inter-ventricular septum, 5.58 ± 0.65 mm ´m - 2; left

ventricular end-diastolic cavity, 28.8 ± 2.7 mm ´m - 2; right

ventricular cavity, 14.2 ± 2.58 mm ´m - 2; left atrial cavity, 16.8 ±1.61 mm ´m - 2; calculated left ventricular mass, 118 g ´m - 2.

There were no signiW cant diV erences (P < 0.05) between the

players when grouped by position, although midW eld players

and full-backs exhibited the highest values for left ventricular

cavity dimension and VÇ O 2max. The absolute value of VÇ O2max

(l ´min - 1) correlated moderately and non-signiW cantly with

both absolute left ventricular cavity dimension (r = 0.38) and

left ventricular mass (r = 0.33). However, VÇ O2max relative to

body mass (ml ´kg - 1 ´min - 1) correlated much more strongly

with left ventricular cavity dimension when normalized to

body mass (r = 0.62, P < 0.01) or normalized to body surface

area (r = 0.53, P < 0.05).

M easures taken by the Japanese national under-17

soccer team to cope with high altitude

H. Aoki, N. O’Hata, T. Fukubayashi, Y. Fujimoto and T. Kohno

Sports Medical Committee, Japan Football Association, Tokyo, Japan

Playing sport at high altitude induces physiological changes,

as the low atmospheric pressure reduces the partial pressure of

oxygen. The eV ects that low atmospheric pressure has on the

human body include the onset of mountain sickness and a

reduction in athletic performance. Therefore, athletes partici-

pating in sporting events held at high altitude must acclimatize

themselves to minimize these eV ects. The aim of this study was

to assess the acclimatization of young soccer players to high

altitude.

The participants were 22 members of a soccer squad aged

no more than 17 years who were still growing. The players

underwent a 10 day training camp at an altitude of 2850 m. In

addition to monitoring for mountain sickness, we performed

blood tests (red blood cells, haemoglobin, haematocrit) and

measured blood pressure and body mass immediately after

waking in the morning.

Fifteen players (68%) displayed at least one symptom

of mountain sickness: headaches, sleep disorders, loss of

appetite, abdominal pain, diarrhoea, cough. The symptoms

persisted for as much as 7 days. On day 5 of the training camp,

the players’ mean haemoglobin concentration was 16.0

g ´ml - 1, an 8.8% increase over the sea-level value (14.7

g ´ml - 1). Haemoglobin concentration remained high on days

7 and 9 (15.8 and 16.1 g ´ml - 1 respectively). The players’

mean haematocrit was 47.5% on day 5 of the training camp, a

9.3% increase over the sea-level value (44.3%). Haematocrit

also remained high on days 7 and 9 (46.6 and 47.8% respec-

tively). The mean red blood cell count of the players was

5.31 ´ 106 ´ml - 1 on day 5 of the training camp, an increase

of 9.2% on the value at sea level (4.87 ´ 106 ´ml - 1). The mean

red blood cell count remained elevated on days 7 and 9

(5.31 ´ 106 and 5.36 ´ 106 ´ml - 1 respectively). On the seventh

morning of the training camp, the body mass of 15 players

(68%) had decreased by an average of 1.3 kg.

Our results show that young soccer players require at least

7 days to acclimatize to high altitude. They are able to take

part in regular training sessions from day 8 onwards.

M odelling the inX uence of thigh muscle cross-sectional

area on vertical jum p performance in young

professional soccer players

A.M. Batterham, C.A. Barnes and D.R. Mullineaux

Centre for Sport Performance, University of Teesside, Middlesbrough, UK

The ability to generate a high muscular power output under-

pins many actions in soccer. To make valid comparisons of

808 Conference communications

performance between players, the inXuence of body size must

be appropriately partitioned out. The aim of this study was to

establish the most appropriate way to control for the inXuence

of thigh cross-sectional area for a test of vertical jumping

power in a group of elite youth soccer players.

Nine healthy male professional soccer players (mean ± s: age

18.1 ± 0.6 years, height 181 ± 6 cm, body mass 70.5 ± 5.0 kg)

volunteered to participate. After a standardized warm-up,

each player performed three vertical jumps with a counter-

movement on a force platform (AMTI OR6-7, Watertown,

MA, USA). Vertical force was sampled at 1000 Hz using a

data acquisition system (AMLAB, Lane Cove, Australia).

Power output was derived from the product of gross vertical

force and vertical velocity of the centre of mass (the impulse of

the net vertical force divided by body mass). The highest value

for the three trials was recorded as peak power output. Using

magnetic resonance imaging (Horizon LX 1.5 T, General

Electric, Milwaukee, WI, USA), thigh muscle cross-sectional

area was determined from an axial T 1-weighted scan at the

mid-point of the femur.

The combined cross-sectional area of the left and right thigh

muscles was 0.33 ± 0.03 m2. The peak power output for the

counter-movement jump was 4981 ± 380 W. The log-linear

relationship between cross-sectional area and peak power

output when expressed in the form y = a ´ xb gave a b exponent

of 0.67 (r2 = 0.73, 95% conW dence intervals = 0.54 ± 1.27). The

95% conW dence intervals for the b exponent in this study

spanned the expected value from dimensionality theory of

unity. We have shown that, when controlling for body size in

inter-individual comparisons of vertical jumping performance

among soccer players, appropriate scaling techniques should

be adopted.

Dietary analysis of a group of English First Division

soccer players

M. Butler, R.P. Craven, L.A. Dickinson, R.F.T. Kinch and

R. Ramsbottom

School of B iological and Molecular Sciences, Oxford B rookes University,

Oxford, UK

Soccer is a physically demanding `hybrid’ game, an endurance

sport incorporating periods of intense exercise interspersed

with periods of much less activity. The intense nature of

the sport, the training demands placed on the players and the

frequency of matches played in the English leagues mean that

an adequate energy supply, both in terms of quality and

quantity, is essential. A pilot showed that junior squad players

were not achieving the recommended daily energy intake

(Department of Health, 1991: Dietary Reference Values for Food

Energy and Nutr ients for the United Kingdom . London: HMSO).

The aim of this study was to determine the total energy intake

and the relative contributions of carbohydrate, fat and protein

in players from the senior squad of an English First Division

club.

Fourteen players aged 18± 30 years (median 23 years), and

with a mean (± s) body mass and height of 80.1 ± 9.2 kg and

181 ± 6 cm respectively, completed a 7 day food diary that

included the weekend of a match. The players’ daily diets were

analysed using the `Dietplan 5’ dietary analysis software. The

mean daily energy intake of the players was 12.9 ± 2.8 MJ; the

percent contributions of carbohydrate, fat and protein were

48.8 ± 3.8%, 31.8 ± 3.0% and 16.2 ± 1.2% respectively. The

daily energy intake of the players was signiW cantly less

(P < 0.05) than the 16.1 ± 1.3 MJ calculated by Ekblom

(ed., 1994: Handbook of Sports M edicine and Science: Football

(Soccer). Oxford: Blackwell) [recommended daily allowance =(BMR ´ 1.7) + 10% TEF]. The energy supplied by fat was

higher, and that supplied by carbohydrate was lower, than the

recommended daily allowances of 25% and 60% respectively.

Our results show that the players, although they achieved

the recommended daily allowance for the general population

of 10.6 MJ (Department of Health, 1991), were not

adequately nutritionally prepared for the demands of training

and playing.

Physiological and perform ance characteristics of

Australian Football League players

D. Buttifant

New South Wales Institute of Sport, Sydney, NSW, Australia

Australian Rules Football is a physically demanding sport that

uses the three energy systems. The game is becoming faster

because of the greater number of interchanges between

players, better technical resources, ground surfaces, skill

Table 1. Mean anthropometric and performance characteristics of Australian Football League players (n = 18)

1993 1994 1995 1996 1997

Age (years)

Height (cm)

Body mass (kg)

Sum of 7 skinfolds

22.7

185

85.7

55.4*

23.8

186

87.3

67.6

24.8

186

88.2

68.7

25.8

186

89.7

67.0

26.8

186

90.5

63.6

Vertical jump (cm)

10 m sprint (s)

20 m sprint (s)

40 m sprint (s)

Estimated VÇ O2max (ml ´kg - 1 ´min - 1)

73.6

Ð

Ð

Ð

53.6

74.3

1.83

3.06

5.37

56.6

76.0

1.82

3.08

5.40

57.9

74.2

1.79

2.97*

Ð

58.7

76.2

1.66*

2.92*

Ð

59.2*

* SigniW cant diVerence: P < 0.05.

Conference communications 809

Table 2. Heat rate (HR; beats ´min - 1) during a game of Australian Rules Football

Mean

HR HRmax

Time < 70%

HRmax (%)

Time 70 ± 85%

HRmax (%)

Time > 85%

HRm ax (%)

Forwards (n = 2)

Backmen (n = 2)

MidW eld (n = 4)

157

152

168

197

192

195

13

20

14

60

53

42*

28

28

44*

* SigniW cant diV erence: P < 0.05.

development and training. The aims of this study were to

determine the physiological responses and to monitor the

performance of Australian Football League (AFL) players

over a 5 year period and to predict future physiological proW les

of AFL players.

The participants, 18 AFL players from the North

Melbourne Football Club, were monitored between 1993 and

1998. Each player performed a vertical jump test, 10, 20

and 40 m sprints, a shuttle test and a time-trial. Body mass and

skinfolds were measured. All tests and measurements were per-

formed between October and December of each year. During

two pre-season games, the heart rates of eight players were

monitored using short-range radio telemetry (Polar Electro,

Kempele, Finland). The anthropometric and performance

characteristics of the players are given in Table 1. Table 2

shows the heart rate responses of the players during match-play.

The results demonstrate improved performances in the

running tests over the period of the study. The players’ heart

rate responses during match-play conW rm the strenuous

physical demands of playing Australian Rules Football.

Agility and speed of soccer players are two diV erent

performance param eters

D. Buttifant, K. Graham and K. Cross

New South Wales Institute of Sport, Sydney, NSW, Australia

It is evident that the game of soccer is becoming more

dynamic, which can be attributed to improvements in the

speed and agility of players. It is unclear whether these two

performance characteristics are closely related. Various tests

have been developed to assess athletes’ agility, including the

505 test, T-test and Illinois test. These tests have produced

variable results, which may be attributed to extrinsic inXu-

ences as well as the diY culty of identifying contributors to

change. The aim of this study was to discriminate between the

speed and agility components of a group of State male soccer

players.

Twenty-one male soccer players attending the New South

Wales Institute of Sport were studied. They were tested twice

over 3 days with 1 day’ s rest in between. The players per-

formed a 2 ´ 20 m sprint test, followed by a nominal 20 m

agility test. Electronic timing gates were used and all tests

were performed on grass. The agility test involved an initial

movement to the left followed by a movement to the right,

this pattern then being repeated. After this pattern had been

completed, the players performed the opposite pattern of

movements. The results of the speed and agility tests are

shown in Table 1. Table 2 is a correlation matrix for the battery

of sprint and agility tests.

The results indicate that only 10% of the mean agility time

can be accounted for by the sprint test. This suggests that

there is no relationship between speed and agility.

A com parison of competition work rates in elite club

and `Super 12’ Rugby Union

M. Deutsch,1 G.A. Kearney2 and N.J. Rehrer1

1School of Physical Education and

2Department of Human Nutrition,

University of Otago, New Zealand

Table 1. Results of the speed and agility tests (mean ± s)

Sprint 20 Agility left (L) Agility right (R) Mean agility Agility L/sprint 20 Agility R/sprint 20 Mean diV erential

3.01 ± 0.02 6.23 ± 0.16 6.12 ± 0.16 6.13 ± 0.15 3.23 ± 0.16 3.12 ± 0.16 3.18 ± 0.15

Table 2. Correlation matrix for the battery of sprint and agility tests (correlation r2)

Sprint 20 Agility left (L) Agility right (R) Mean agility Agility L/sprint 20 Agility R/sprint 20 Mean diV .

Sprint 20 (S20)

Agility L

Agility R

Mean agility

Agility L/S20

Agility R/S20

Mean diV .

1

0.092

0.093

0.109

0.049

0.051

0.043

1

0.481

0.849

0.742

0.297

0.590

1

0.844

0.299

0.735

0.585

1

0.587

0.578

0.694

1

0.461

0.842

1

0.837 1


The work rates characteristic of professional Rugby Union

have yet to be determined. Without information regarding the

demands of rugby at these standards, and the diV erences

between playing positions, speciW city in testing and training is

unlikely to be achieved.

We collected video data for 67 players over two seasons,

during competition in Dunedin W rst-grade and Otago `Super

12’ matches. Movements were classiW ed from video playback

as work (cruising, sprinting, tackling, jumping, rucking or

mauling, scrummaging) or rest (inactive, walking, jogging,

shuZ ing sideways or backwards). The aims of this study were

to determine the amounts of work performed by each player as

well as the distribution of exercise and rest periods throughout

the match. Comparisons were between forwards and backs

at each of the two standards of play, and between the two

standards for forwards and backs.

The results revealed signiW cant diV erences at club standard

between forwards and backs for total work performed

(mean ± sxÅ : 611 ± 24.9 vs 233 ± 8.4 s, P < 0.001), frequency

of work bouts (118 ± 4.3 vs 54.8 ± 2.1, P < 0.001), mean

duration of work periods (5.2 ± 0.1 vs 4.3 ± 0.1 s, P < 0.001)

and mean duration of rest periods (33.5 ± 1.6 vs 78.0 ± 3.5 s,

P < 0.001). Similar diV erences were noted for `Super 12’

between forwards and backs: total work performed (613 ±26.3 vs 217 ± 17.3 s, P < 0.001), frequency of work bouts

(122 ± 5.9 vs 46.9 ± 3.0, P < 0.001), mean duration of work

periods (5.1 ± 0.1 vs 4.7 ± 0.3 s, P < 0.001), mean duration of

rest periods (37.1 ± 1.7 vs 99.5 ± 6.7 s, P < 0.001) as well as

mean work-to-rest ratio (x : 1; 0.5 ± 0.1 vs 0.3 ± 0.1, P = 0.02).

These diV erences conW rm a higher intensity of play among

forwards compared with backs. The only diV erences between

club rugby and `Super 12’ were observed among backs, who

diV ered signiW cantly in their frequency of work (P = 0.04) and

mean duration of rest periods (P = 0.004), reXecting a more

continuous and more intense style of play among club players.

Our results indicate a need for speciW city in both training

and W tness testing for forwards and backs. The lower work

rates observed among `Super 12’ backs may reXect a more

structured and higher quality of forward play in professional

Rugby Union.

Work rate and cardiovascular stress among elite soccer

referees

S. D’ Ottavio and C. Castagna

Italian Soccer Federation (FIGC) and Italian Referees Association (AIA),

Rome, Italy

The aim of this study was to establish the work-rate proW le

and cardiovascular stress of 18 elite soccer referees during 18

Italian First Division matches. The referees’ heart rates were

monitored using short-range radio telemetry (Polar Electro,

Kempele, Finland) and detailed match analysis was performed

by trigonometry (Play ControllerTM).

During the matches, the referees covered a total distance

of 11.4 ± 1.6 km (mean ± s). Mean heart rate during the W rst

and second halves was 163 ± 5 and 162 ± 5 beats ´min - 1

(P = 0.72). The referees’ mean heart rate for the entire match

was 163 ± 5 beats ´min - 1, equivalent to 89.1% of estimated

maximal heart rate. However, during the W rst 15 min of play,

mean heart rate was signiW cantly (P < 0.05) lower than during

the second and third 15 min periods of the W rst half. The

overall mean distance covered during the W rst and second

halves was 5757 ± 703 and 5619 ± 939 m respectively (P >

0.05). The referees covered less distance when running

backwards (W rst vs second half: 737 ± 339 vs 578 ± 249 m,

P < 0.05) and sideways (W rst vs second half: 133 ± 109 vs

48 ± 31 m, P < 0.05). Altogether, high-intensity exercise

(running at speeds faster than 18.1 km ´h - 1) accounted for

41.7% of the total distance covered during the matches. The

distance covered at this high intensity did not diV er sig-

niW cantly between halves (P > 0.05).

Our results suggest that soccer refereeing is an intermittent

activity that sometimes reaches near maximal intensities.

Bouts of sprinting never last more than a few seconds, but

the demands placed on referees sometimes exceed those

reported for outW eld players. We found no signs of cardio-

vascular drift between the W rst and second halves. We con-

clude that, at the elite standard of play, soccer refereeing

places high physiological demands on oY cials. Because of the

nature of oY ciating, speciW c training and W tness assessments

are required.

Anthropom etric and physiological diV erences between

groups of New Zealand national soccer players based

on sex and age

M.N. Dowson, J.B. Cronin and J.D. Presland

Auckland Institute of Technology, Auckland, New Zealand

The aim of this study was to determine the anthropometric

and physiological proW les of New Zealand soccer players

based on sex and age. Normative data were established and

compared with those of other international standard soccer

players.

During pre-season, teams representing New Zealand

(men’ s under-15, under-17, under-19 and senior squads;

women’ s senior squad) were assessed for a number of

anthropometric variables (height, weight and sum of two

skinfolds), VÇ O 2max (multi-stage W tness test), 10 and 20 m

sprint times (electronic timing lights) and leg power (contact

mat). The results were compared using analysis of variance.

A criterion alpha of P < 0.05 was adopted.

The senior men had a higher VÇ O2max (60.5 ± 2.6 ml ´kg - 1 ´

min - 1) than the men’ s under-15 (51.0 ± 4.2 ml ´kg - 1 ´min - 1)

and under-17 (56.1 ± 5.2 ml ´ kg - 1 ´min - 1) squads and the

women’ s senior squad (49.1 ± 5.5 ml ´kg - 1 ´min - 1). The mean

VÇ O2max values of the men’ s and women’ s senior squads were

similar to those of other national squads. The senior men’ s 10

and 20 m sprint times were faster than those of the men’ s

under-15 and women’ s senior squads; over these distances the

women were slower than all but the men’ s under-15 squad.

Leg power (as indicated by vertical jumping) increased with

age. The senior women (33.8 ± 3.8 cm) had less leg power

than the men’ s under-15 squad (38.0 ± 4.8 cm).

In summary, the anthropometric and physiological proW les

improved with age; the diV erences became less distinct as

maturity was reached, as indicated by the comparison of the


men’ s under-19 and senior squads. In the main, the senior

women’ s proW les were similar to those of the men’ s under-15

squad.

M etabolic and physiological responses to a laboratory-

based, soccer-speciW c intermittent protocol on a

non-motorized treadm ill

B. Drust,1 T. Reilly2 and N.T. Cable2

1Centre for Sport Performance, University of Teesside, Middlesbrough

and 2Research Institute for Sport and Exercise Sciences, Liverpool

John Moores University, Liverpool, UK

The lack of experimental models that can be used to deter-

mine the demands of soccer match-play has promoted

attempts to develop laboratory-based, soccer-speciW c inter-

mittent protocols. Seventeen full-time professional soccer

players were W lmed during international match-play for the

determination of work-rate proW les. The amount of time spent

in each of W ve categories (static 15%, walking 50%, jogging

30%, cruising 4%, sprinting 1%) was used to establish the

activity in the exercise protocol.

Six male university soccer players (mean ± s: age 27 ± 2

years, height 177 ± 3 cm, body mass 72.2 ± 1.5 kg, VÇ O2max

58.9 ± 3.5 ml ´kg - 1 ´min - 1) completed a 90 min soccer-speciW c

intermittent exercise protocol. The total distance covered

during the protocol (9500 ± 400 m) did not diV er signiW -

cantly (P > 0.05) from that covered during match-play

(8638 ± 1158 m). The physiological and metabolic responses

also approximated the physiological strain associated with

soccer match-play (Bangsbo, 1994: Acta Physiologica

Scandinavica, 151, suppl. 619). Mean oxygen consumption

and mean heart rate were 2.5 ± 0.2 l ´min - 1 (approximately

65± 70% VÇ O2max) and 160 ± 6 beats ´min - 1 respectively. The

concentrations of plasma glucose and free fatty acids were

elevated as a result of the exercise protocol, similar to those

observed in match-play (pre- vs post-exercise: plasma glucose

5.0 ± 0.6 vs 5.5 ± 0.9 mmol ´ l - 1; plasma free fatty acids

323 ± 266 vs 1557 ± 668 mmol ´ l - 1).

Our results suggest the protocol used is suitable for the

determination of metabolic and physiological responses to

soccer-speciW c intermittent exercise.

Longitudinal change in aerobic capacity throughout the

playing year in English professional soccer players

G.M.J. Dunbar

Nike Laboratory, London, UK

Previous research investigating changes in the endurance

W tness of soccer players throughout a season has often used

maximum oxygen consumption ± either by direct deter-

mination or estimated from W eld tests ± as the criterion

measure of aerobic W tness. The aim of this study was to deter-

mine changes in aerobic capacity throughout a year among a

squad of elite English professional soccer players using lactate

proW les.

Although 33 players were tested during the year, only

11 participated in all four tests, held in July, September,

January and May, corresponding to the start of pre-season

training, early, mid- and late season respectively. Submaximal

running was performed on a motor-driven treadmill (Power-

jog GX100) at level gradient and consisted of W ve progressive

stages of 3 min each. Heart rate was monitored throughout

using short-range radio telemetry (Polar Electro, Kempele,

Finland) and earlobe whole-blood samples were taken at

the end of each stage for lactate determination (Analox

GM6). The running speed at a whole-blood lactate concen-

tration of 2 and 3 mmol ´ l - 1(n-2 mmol ´ l - 1 and n-3 mmol ´ l - 1

respectively) was determined using linear interpolation (see

Table 1).

Although running speeds at the reference blood lactate

concentrations were faster and the skinfold measurements

were lower in January than at the other times of the year,

especially May, analysis of variance could reveal no statistically

signiW cant diV erences for these variables throughout the year

(P > 0.05). This is probably the result of individual variation

in changes in W tness throughout the playing season. Despite

a trend for running speed at the reference blood lactate con-

centrations to be lower at the end of the playing season, there

were no signiW cant diV erences in aerobic capacity throughout

the year, as determined from lactate proW les, in elite English

professional soccer players.

Quantifying the workload of soccer players during

training and com petition

T.R. Flanagan and E. Merrick

Royal Melbourne Institute of Technology, Victorian Institute of Sport,

Melbourne, Victoria, Australia

The design of a high-performance training programme

for elite soccer players should focus on the development of

skills while replicating the demands of a match during

practice. The main limitation to an integrated physical and

technical approach is the diY culty the coach has in accurately

quantifying training workloads and intensities. A training

category system was developed to simplify the process of

Table 1. Sum of skinfold measurements, n-2 mmol ´ l - 1 and n-3 mmol ´ l - 1

(mean ± s)

June July January May

Sum of skinfolds (mm)

n-2 mmol ´ l - 1 (km ´h - 1)

n-3 mmol ´ l - 1 (km ´h - 1

)

31.3 ± 7.3

14.3 ± 1.4

15.4 ± 1.2

28.6 ± 5.6

14.5 ± 1.2

15.4 ± 1.1

27.7 ± 6.3

14.8 ± 1.5

15.7 ± 1.6

28.5 ± 8.6

13.9 ± 1.7

15.0 ± 1.5


monitoring the workload of players based on the formula

that physical workload is equal to the product of the duration

and intensity of exercise. Estimating work intensity from

heart rates measured during activity is the most practical

method.

Thirteen elite junior soccer players (mean ± s: age 17 ± 1

years, height 177 ± 6 cm, body mass 72.3 ± 5.2 kg, maximum

heart rate 210 ± 9 beats ´min - 1) were recruited for laboratory

testing. The players ran on a motorized treadmill at speeds of

4, 8, 12, 16 and 21 km ´h - 1 (Bangsbo et al., 1991: Canadian

Journal of Sports Science, 16, 110 ± 116) for 2± 3 min each

(until a steady state had been reached), with 3 min recovery

between bouts. Intensity of exercise was calculated using

linear regression equations for heart rate versus running

speed and running speed versus an intensity scale. The

categories, with heart rate zones in parentheses, were as

follows: active recovery (93± 114 beats ´min - 1), low-intensity

exercise (115± 135 beats ´min - 1), moderate-intensity exercise

(136± 155 beats ´min - 1), high-intensity exercise (156± 178

beats ´min - 1), very high-intensity exercise (> 178 beats ´min - 1).

The training category system allows coaches to test diV erent

models of overload, resulting in optimal training responses

and improvements in performance. The system is also an

eV ective way to periodize workload when coaching with the

holistic philosophy of developing the technical, tactical and

physical capacities of soccer players simultaneously.

Talent identiW cation in elite youth soccer players:

Physical and physiological characteristics

A.M. Franks, A.M. Williams, T. Reilly and A. Nevill

Research Institute for Sport and Exercise Sciences, Liverpool John Moores

University, Liverpool, UK

Identifying, developing and nurturing talented players is a

priority in soccer. Players’ anthropometric and physiological

characteristics are recognized as important determinants of

performance. Consequently, physical and physiological assess-

ment procedures may assist in the identiW cation of young

talent (Carter, 1982: Physical Structure of Olympic Athletes.

Part I: The M ontreal Olympic Games Anthropological Project.

Basel: Karger). Our concern here was with the prediction

of future success in soccer from physical and physiological

measurements.

Data from 64 international youth soccer players aged 14± 16

years were analysed retrospectively. Measurements included

height, body mass, percent body fat, aerobic performance

(20 m shuttle run test) and anaerobic performance (15 and

40 m sprint times). Players were categorized according to

playing `positions’ and whether they had been oV ered a

`professional’ contract (i.e. successful vs unsuccessful). No

signiW cant diV erences between successful and unsuccessful

players were indicated by analysis of variance. There were

diV erences across playing positions in height (F3,59 = 9.78,

P < 0.001), body mass (F3,59 = 10.87, P < 0.001) and percent

body fat (F3,42 = 6.12, P < 0.001). Goal-keepers were the

tallest (184 ± 2 cm) and heaviest (79.4 ± 1.8 kg) and had most

body fat (14.0 ± 0.7%); forwards were the smallest (172 ± 2

cm) and midW eld players were lightest (67.6 ± 1.1 kg) and had

least body fat (10.5 ± 0.4%). Players had high aerobic and

anaerobic performance regardless of playing positions.

Although these measurements appear useful for initial

talent identiW cation, our observations suggest that none of

the physical and physiological characteristics successfully

predicted subsequent success in soccer. Future research

should attempt to identify psychological, educational and

sociological predictors of talent in soccer.

The development and evaluation of a task-speciW c

W tness test for Association Football referees

R.A. Harley, R. Banks and J. Doust

University of B righton, East Sussex, UK

Time± motion analysis (Catterall et al., 1993: B ritish Journal of

Sports M edicine, 27, 193 ± 196; Johnson and McNaughton,

1994: Australian Journal of Science and Medicine in Sport, 26,

67± 72) has revealed that referees on average jog 50%, walk

20%, run backwards 20% and sprint 10% of the time during

a match. The current W tness assessment of amateur referees

involves running 2600 m around an athletics track in 12 min.

This test is not speciW c to the movement mechanics of foot-

ball refereeing and requires pace judgement. The aim of this

study was to develop and evaluate a task-speciW c test to assess

the endurance W tness of Association Football referees. An

incremental test was designed based on time± motion analysis

data. The participants were required to complete laps around

a 50 m grass square at a set pace dictated by instructions on an

audio tape. They jogged 50 m, had 6 s rest, then ran back-

wards for 20 m, turned and sprinted 10 m followed by a

20 m walk. This sequence was then repeated, with the time to

complete laps decreasing every 3 min. Sixteen Sussex amateur

County League football referees (age 36.6 ± 7.7 years) per-

formed maximal tests on three separate occasions. An incre-

mental treadmill test to volitional exhaustion, with expired

air collections each minute, was used to assess VÇ O2max; the

multi-stage W tness test (Leger et al., 1988: Journal of Sports

Sciences, 6, 93± 101) and the new task-speciW c test. Distances

covered on the new test were signiW cantly correlated with the

multi-stage W tness test (r = 0.73, P < 0.0005) and the tread-

mill test (r = 0.82, P < 0.0005). An additional study was con-

ducted to assess the reproducibility and objectivity of the new

test. Twelve Sussex amateur County football referees, who had

no previous experience of the task-speciW c test, performed the

test on two separate occasions 1 week apart. Three experi-

menters assessed each referee ’ s performance on the W rst test.

There was no signiW cant diV erence (t = 1.1, P > 0.05), but

a signiW cant correlation (r = 0.95, P < 0.0001) was found

to exist between scores, with a coeY cient of variation of

5.4%. No signiW cant diV erences (F = 0.000) were found to

exist between the three experimenters’ interpretations of the

scores. The new test has ecological validity (based upon

movement mechanics) and criterion validity. It is repro-

ducible and objective and can therefore be used to assess the

aerobic W tness levels of football referees in a task-speciW c

environment.


An analysis of m ovem ent patterns and physiological

strain in relation to optimal positioning of Association

Football referees

R.A. Harley, K. Tozer and J. Doust

University of B righton, East Sussex, UK

For Association Football referees to make the correct

decisions during a match, they should take up the optimal

vantage point. The aim of this study was to analyse the

movement patterns and physiological strain of Association

Football referees at amateur County League standard.

Referees’ ability to attain the correct position at the correct

time was also studied to investigate the relationship between

distance covered and quality of positioning.

The movements of 14 referees (mean ± s: age 37.5 ± 6.7

years, body mass 82.2 ± 9.5 kg) were video-recorded during

County League matches. Distances covered were analysed and

placed in four movement categories: walk, jog, backwards run,

sprint. Distances covered were estimated using average stride

length for the four movement categories. Heart rate was

recorded using short-range radio telemetry (Sports Tester,

Polar Electro, Kempele, Finland). An experienced referee

assessor graded the referees on their positioning for each

match using a movement analysis questionnaire (W ve questions

graded on a scale from 1 to 10, for each half), with regard to

their ability to obtain the optimal positions in the correct time

to give decisions. The score was given as a percentage, from 0%

(being in the wrong place all of the time) to 100% (being in the

right place at the right time, all of the time). Each referee

undertook a submaximal incremental laboratory treadmill test

with heart rate and oxygen uptake being measured in the last

minute of each stage until heart rate reached 80% of predicted

maximum to establish a heart rate± oxygen uptake relationship.

The total distance covered was 7496 ± 1122 m, which

comprised 42% walking, 47% jogging, 8% backwards running

and 3% sprinting. The distance covered between the W rst

(4017 ± 596 m) and second (3479 ± 574 m) halves decreased

signiW cantly (P < 0.01). Mean match heart rate was 162

beats ´min - 1; it did not diV er signiW cantly between halves.

Average physiological work rate during the match predicted

from heart rate and oxygen uptake data was 80.0 ± 7.6%

VÇ O 2max, which did not diV er signiW cantly between halves.

The mean assessment score was 65.4% (range 40± 92%) and

was signiW cantly correlated with distance covered (r = 0.80).

The mean assessment scores for the W rst (70%) and second

(62%) halves decreased signiW cantly (P < 0.01).

The results demonstrate the importance of aerobic W tness

for the referee to be in the `right place at the right time’ to

make decisions. The fact that distances covered and assess-

ment scores decreased signiW cantly between halves suggests an

inability of referees to sustain the required work rate.

DiV erences in strength and endurance between elite

m ale and fem ale soccer players

J. Helgerud, J. HoV and U. Wislù V

Department of Sport Sciences, Norwegian University of Science and

Technology, Trondheim, Norway

During the last decade, women’ s soccer has become a popular

event. DiV erences between male and female athletes are not

only genetic, but are also inXuenced by standard of selection,

training and competition. Dimensional scaling must be con-

sidered when comparing groups with diV erent body masses.

The main aim of the present study was to identify diV erences

in cardiovascular endurance capacity as well as muscular

strength and power in elite male and female soccer players in

Norway. We also assessed maximal oxygen uptake in pro-

portion to body mass for soccer players. A further aim was

to establish normative data for elite female soccer players.

One men’ s and one women’ s team from the Norwegian elite

soccer league participated in the study. Trondheims é rn

(women, n = 12) and Rosenborg (men, n = 14) have been the

most successful teams in Norway over the last 5 years. Results

showed that maximal oxygen uptake did not increase in

proportion to body mass in elite soccer players. This lends

support to the argument that dimensional scaling should be

used with soccer players. Mean results for the women’ s team

were 54.0 ml ´kg - 1 ´min - 1 or 152 ml ´ kg - 0.75 ´min - 1 for maximal

oxygen uptake, 112.5 kg or 7.1 kg ´body mass - 0.67 for 90°squats, 43.8 kg or 2.75 kg ´body mass - 0.67 for bench press;

vertical jump height was 42.9 cm. Considerable diV erences

existed between the sexes. Maximal oxygen uptake, squats and

jump height were 20± 25% lower for women compared with

men, and the bench press results were 40% lower in women.

Correlations between W eld and laboratory tests of

strength, power and m uscular endurance for elite

Australian Rules footballers

C. Hrysomallis,1 R. Koski,1 M. McCoy2 and J. Wrigley1

1Centre for Rehabilitation, Exercise and Sport Science, Victoria University

of Technology, Melbourne, Australia and 2Richmond Football Club,

Australia

Field and laboratory tests are frequently used to evaluate the

physiological capacities of athletes. Field tests are generally

used where utility and cost are important, whereas laboratory

tests are used where additional precision and control are

required. The aim of this study was to determine the relation-

ship between some common W eld tests and laboratory tests.

Twenty-two players from the Richmond Australian Rules

Football Club served as participants. The W eld tests included

sprint times determined by timing lights placed at 0, 5, 10

and 20 m. A vertical jump test was executed using a W ve-step

run-up and one-legged take-oV . A standing long jump was

performed in a long jump pit. The laboratory tests were used

to determine the strength and muscular endurance of the

quadriceps and hamstring muscle groups using an isokinetic

dynamometer. Strength was assessed by determining the peak

concentric torque at 1.05, 4.18 and 6.27 rad ´ s - 1 (60, 240 and

360° ´ s - 1). Muscular endurance was assessed by determining

the total work for 20 repetitions of concentric and eccentric

muscle actions of the quadriceps and hamstrings at 1.57

rad ´ s - 1 (90° ´s - 1). Pearson correlation coeY cients were used

to determine signiW cant relationships (P < 0.01) between the

W eld and laboratory test results.


Vertical jump was signiW cantly correlated with the measure

of muscular endurance for both the quadriceps and ham-

strings and both concentrically and eccentrically (r-values

ranged from 0.62 to 0.69). There was also a signiW cant rela-

tionship between vertical jump and one of the strength

measures (quadriceps peak concentric torque at 4.18 rad ´ s - 1,

r = 0.59). The vertical jump appears to be a reasonable indi-

cator of muscular performance. Sprint times to 5 and 10 m

were signiW cantly correlated with hamstring peak concentric

torque at 4.18 and 6.27 rad ´s - 1 (r-values ranged from - 0.56

to - 0.62).

The W ndings of this study can be used to determine which

W eld tests to administer in place of laboratory tests if access is

limited. Since hamstring strength at high speeds was related

to sprinting, strengthening this muscle group could improve

sprint times over short distances.

Anthropom etric characteristics of 11- to 12-year-old

Flemish soccer players

M. Janssens, B. Van Renterghem and J. Vrijens

Department of Movement and Sport Sciences, University of Ghent,

Ghent, B elgium

The aims of this study were to establish the anthropometric

proW le of 11- to 12-year old Flemish soccer players, to com-

pare this proW le with that of the average Flemish boy of the

same age, and to determine if diV erences in playing standard

are linked to anthropometric diV erences.

In total, 165 Flemish soccer players aged 11± 12 years were

divided into three groups: Group 1, W rst and second leagues;

Group 2, third and fourth leagues; Group 3, regional league.

The anthropometric measurements taken included: height;

body mass; sum of W ve skinfolds (biceps, triceps, subscapular,

supraspinal and calf ); biacromial, bicristal, femur and

humerus widths; and calf and biceps girths. The body mass

(BMI) and somatotype (Heath-Carter method) were also

calculated. Descriptive statistics and one-way analysis of

variance were applied.

The anthropometric proW le of the soccer players in this

study were as follows (mean ± s): age 12.2 ± 0.7 years, height

151 ± 8 cm, body mass 40.1 ± 7.0 kg, sum of W ve skinfolds

35.6 ± 14.8 mm, BMI 17.4 ± 2.8, endomorphy 2.4 ± 1.1,

mesomorphy 4.0 ± 1.0, ectomorphy 3.8 ± 1.2. Compared with

the average age-matched Flemish boy, soccer players aged

11± 12 years have a similar anthropometric proW le except for

the sum of W ve skinfolds (soccer players vs average boy: 35.6 vs

45.4 mm).

The players in Group 1 had a signiW cantly lower body mass

than players in Group 3 (38.8 vs 42.8 kg, P < 0.05). Players in

Group 1 had signiW cantly lower values for sum of W ve skinfolds

(30.4 vs 36.9 and 44.1 mm) and endomorphy (1.9 vs 2.6 and

2.8) than players in Groups 2 and 3 (P < 0.05). There were

also signiW cant diV erences in mesomorphy: players in Group 3

had signiW cantly higher values than players in Group 1 (4.4 vs

3.8, P < 0.05). This latter W nding may be a result of fat-free

mass, which was greater (though not signiW cantly so) in Group

3 (34.5 vs 32.9 kg).

In conclusion, it would appear that, for young soccer

players, there are no speciW c performance-related anthropo-

metric characteristics, with the exception of fat mass.

Measures taken by the Japan women’s soccer team to

cope with the physiological eV ects of high air

tem perature

T. Kohno, N. O’ Hata, H. Aoki, T. Fukubayashi and

Y. Fujimoto

Sports Medical Committee, Japan Football Association, Tokyo, Japan

High temperatures not only aV ect a player’ s performance, but

can also trigger heat-related illnesses, owing to dehydration for

example. Sports activities are often suspended or restricted

because of this. In international competition, however, games

are played despite high environmental temperatures. When

athletes take part in such events, measures need to be con-

sidered to counter or alleviate the eV ects of heat. In this

study, we focus on the measures recently introduced to help

members of the Japan women’ s soccer team cope with high

environmental temperatures.

The participants were 28 members of the women’ s national

team aged 17± 30 years (mean 22.5 years). During 7 days of

training, body mass was measured immediately after getting

up in the morning, and before and after each practice session

and match. Blood samples were also taken on 3 days. The

highest and lowest wet bulb globe temperatures during the

study were 32.7°C and 27.7°C respectively; the mean was

30.7°C.

The players’ body mass was reduced on the morning after

web bulb globe temperature exceeded 31.0°C, recovered the

following day after resting, before falling again once they

resumed practice. Their blood urea nitrogen rose to 22.8 ±4.6 mg ´dl - 1 (mean ± s) on the day after a game, fell to

17.8 ± 4.1 mg ´dl - 1 the next day, and then fell further to within

the normal range (16.4 ± 3.6 mg ´dl - 1) on the third day after a

rest. Creatine kinase was measured as 306 ± 213 IU ´ l - 1 on day

1, falling to 257 ± 137 IU ´ l - 1 on day 2, and falling further to

within normal limits (137 ± 57 IU ´l - 1) on day 3. The body

mass of the players at the end of a game was reduced 2.8%

when allowed to drink at half-time only, but was reduced

by only 1.5% when they were allowed to drink every 15 min

during the game and at half-time.

Our results indicate that the body mass of women soccer

players is reduced the morning after the wet bulb globe

temperature exceeds 31.0°C and that it is important for them

to take adequate rest. Changes in blood urea nitrogen and

creatine kinase suggest that these athletes should rest every

1 in 3 days. We also found that, by increasing the rate of

replenishment of water, weight loss could be reduced to

1.5% after a game.

Changes in the W tness of elite under-18 Australian Rules

football players: A longitudinal analysis

D.B. Marchant

Victoria University of Technology, Melbourne, Australia


The 16 teams competing in the Australian Rules Football

League (AFL) recruit promising junior players of 17 years

and up in an annual national draft. In assessing a player’ s

potential for making a successful transition to elite open-

age competition, AFL club personnel consider, among

other indicators, physiological performance data (i.e. W tness

test results). Over the last 4 years, the AFL has conducted an

annual talent camp in the immediate post-season. Essentially,

the talent camp allows AFL personnel to observe at W rst-

hand the football skills, psychomotor capabilities and physical

W tness of the best under-age players in Australia. The battery

of W tness and anthropometry tests includes: vertical jump,

one-repetition maximum bench press (1 RM BP), 20 m

shuttle run, sum of skinfolds, height and body mass. The aim

of this study was to determine any changes in the physical

capabilities of elite under-age players in recent years.

Analysis of variance was conducted on the W tness test results

of the last 4 years. SigniW cant diV erences across years were

found for standing vertical jump (F3,243 = 6.60, P < 0.0001),

1 RM BP (F3,242 = 9.20, P < 0.0001), 20 m shuttle run

(F3,236 = 37.40, P < 0.0001) and sum of skinfolds (F3,273 =26.10, P < 0.0001). In all cases, the 1997 cohort of talent

camp players outperformed their 1994 counterparts. No

signiW cant diV erences were found for height or body mass.

The results clearly demonstrate that elite junior players are

progressively becoming more physically capable, and hence

better prepared to make the transition to AFL competition.

The reliability and validity of two tests of soccer skill

S.J. McGregor, M. Hulse, A. Strudwick and C. Williams

Loughborough University, Loughborough, UK

There has been relatively little research on fatigue and soccer

skill, probably because of the diY culty in assessing skill in a

reliable way. The aim of this study was to devise two valid and

reliable tests of soccer skill.

Sixty-seven male university soccer players volunteered to

participate in the study. Thirty players were randomly

assigned to the Loughborough Soccer Passing Test (LSPT)

and 37 to the Loughborough Soccer Dribbling Test (LSDT).

The LSPT involved the performance of 16 passes from a cen-

tral zone to four marked areas. The time to complete the 16

passes was recorded. In the LSDT, players dribbled a ball

between a line of six cones, 3 m apart, as fast as possible. Ten

trials were completed with a 1 min break between each. The

sum of the times for all 10 trials was used as the W nal score for

this test. Following familiarization, the participants performed

the skill tests twice so that the level of agreement between

the two trials could be calculated (Bland and Altman, 1986:

Lancet, i, 307 ± 310) and the reliability of each test determined.

The score generated from each test was correlated (Spearman’s

rank order) with the group’ s skill ability ranking, as assessed

by the players’ coach, to determine a validity coeY cient.

The validity coeY cient was signiW cant for both tests: LSDT

(r = 0.78, P < 0.01); LSPT (r = 0.64, P < 0.05). The 95%

conW dence intervals were 0.08 ± 6.43 s for the LSDT (mean

score 148.26 s), and - 0.03 to 6.14 s for the LSPT (mean score

55.10 s). The results of this study suggest that the LSDT and

LSPT are reliable indicators of soccer skill.

The inX uence of X uid ingestion on exercise m etabolism

during prolonged intermittent, high-intensity shuttle

running

S.J.McGregor, C.W. Nicholas, S. Drawer, A. Grayson and

C. Williams

Loughborough University, Loughborough, UK

The Loughborough Intermittent Shuttle Test (LIST) was

designed to match the performance demands of multiple

sprint sports such as soccer (Nicholas et al., 1995: Journal

of Sports Science s, 13, 283 ± 290). In the absence of Xuid inges-

tion, soccer skill deteriorated following the 90 min LIST

(McGregor et al., 1997: Communication to the Second Annual

Cong ress of the European College of Sports Science, Copenhagen,

August). Water ingestion during prolonged exercise spares

muscle glycogen (Hargreaves et al., 1996: Journal of Applied

Physiology, 80, 363 ± 366) and may therefore delay the onset

of fatigue. The aim of the present study was to determine

the inXuence of Xuid ingestion on exercise metabolism during

performance of the LIST.

Ten male games players performed the LIST on three

occasions each at least 1 week apart. The participants acted

as their own control in a repeated-measures crossover design,

either ingesting a 6.4% carbohydrate electrolyte solution,

placebo or no Xuid. Venous blood and expired air samples

were collected throughout the test. Free fatty acids were lower

(P < 0.01) at the end of exercise during both the carbohydrate

(0.39 ± 0.1 mmol ´ l - 1) and placebo (0.66 ± 0.1 mmol ´ l - 1)

trials compared with the no-Xuid trial (0.88 ± 0.1 mmol ´ l - 1).

Cortisol and aldosterone responses were also lower (P < 0.01)

during the carbohydrate and no-Xuid trials. There was no

diV erence in respiratory exchange ratio between trials. In

summary, Xuid ingestion did not appear to cause changes in

the rates of fat and carbohydrate oxidation, even though there

were diV erences in plasma free fatty acid concentrations.

Don’t let your kids grow up to be hookers

P.D. Milburn and A.W. Parker

University of Otago, Dunedin, New Zealand

The adolescent hooker in Rugby Union is the player most

vulnerable to serious spinal injury. Although this might result

from aggressive play, it is more likely to result from a mis-

match of player size, ability or skill level. Previous research has

shown a discrepancy in the perception of coaches in terms

of selection of players and the demands on these players,

resulting in selection of players physically unsuited to the

demands of the playing position.

The aim of this study was to identify the structural and

physical characteristics related to playing in the diV erent

positions in the front-row. This was achieved by assessing

anthropometric and performance characteristics of 262

adolescent front-row forwards and applying regression and


discriminant analysis techniques to distinguish between

groups and to predict group membership.

We found that current selection procedures incorrectly

selected a high percentage of post-adolescent front-row

forwards and that a high proportion were playing in the wrong

grade. Body dimensions rather than body type appeared to

be the main factor in selecting adolescent front-row players.

Although nearly 80% of all hookers in this sample were

correctly selected, only 39% A-grade hookers had the physical

attributes to play safely in this position. This was probably

because players’ size was not a disadvantage in playing hooker

provided they had adequate upper body and trunk strength.

Furthermore, age was not a good discriminator for playing

standard under 15 years of age; over 15, players could compete

fairly against players of the same age. Therefore, hookers need

to have the right physical attributes and be coached correctly,

and administrators should change the way adolescents are

grouped in junior rugby.

Motion characteristics of an elite soccer player during

a game

O. Miyagi,1 J. Ohashi2 and K. Kitagawa3

1Department of Physical Education, National Defense Academy,

Kanagawa, 2Laboratory for Sports Science, Daito B unka University,

Saitama and 3Laboratory for Exercise Physiology and B iomechanics,

Chukyo University, Aichi, Japan

This single-subject study was designed to clarify the motion

characteristics during a game and the game-to-game vari-

ability in movement patterns of an elite soccer player. The

forward player represented a professional soccer team in

Japan. He played for the Yugoslavia team in the 1998 World

Cup. The parameters measured were movement distance,

speed and locus during the game. These were measured

throughout the game using a triangular surveying method.

This system records the player’ s movement as angular

changes, which were measured by two potentiometers outside

of the W eld of play. These angles were then converted to con-

tinuous x,y coordinates so that the player’ s speed could be

observed in detail. The measurements were made six times

during professional soccer league games in Japan. Movement

distance covered by the player during the game averaged

10,460 ± 591 m: 5315 ± 330 m in the W rst half and 5141 ±306 m in the second half. Maximum movement speed during

the game was approximately 9 m ´s - 1. About 70% of the move-

ment distance was covered at below 4 m ´ s - 1. These results are

comparable with those reported in the literature (Reilly, 1997:

Journal of Sports Science s, 15, 257 ± 263) and suggest a relatively

low variability in motion characteristics.

Tim e± m otion analysis of elite touch football players

D. O’ Connor

James Cook University, Townsville, Australia

Touch football is now a six-a-side game using the same W eld

dimensions as the seven-a-side game. The aims of this study

were to determine the demands placed on players and to

identify the dominant movement patterns used in elite six-

a-side touch football. The evaluation of energy requirements

will help in the development of eV ective and speciW c training

programmes for elite touch football players. Two men’ s and

two women’ s games were video-taped with 50 players (30

males and 20 females) analysed in total. The movement

patterns of each player were analysed only when the game was

in progress. Heart rate was recorded continuously using short-

range radio telemetry (PE3000 Sport Tester, Polar Electro,

Kempele, Finland) from the start of the game until the W nal

whistle. Lactate was measured from 5 min before the end of

the game to 5 min post-game using an ACUSPORT analyser.

Reliability coeY cients ranged from 0.85 to 0.89 for the

various movement patterns.

Mean heart rate recorded in the men’ s and women’ s games

was 177 ± 7 and 179 ± 8 beats ´min - 1. There were no sig-

niW cant diV erences between playing position and heart rate

responses during the game. The lactate concentration of the

male and female players was 5.7 ± 1.4 and 5.9 ± 3.1 mmol ´ l - 1

respectively. When playing position was taken into consider-

ation, the outside players and midW eld players had a lactate

concentration of 7.5 and 4.6 mmol ´ l - 1 respectively. The

categories stationary, walking and jogging forward were

classiW ed as low-intensity activities (42% of total game time)

and supported by the aerobic energy system. Sprinting,

running backwards and sideways were deemed high-intensity

activities (12% of total game time) that used the anaerobic

energy system. The results show that 46% of the total game

time of these players was spent on the sideline, with inter-

changes occurring 5± 8 times during a game. Female players

walked on more occasions than male players and interchanged

less frequently. However, both males and females spent

19% of total game time jogging forward and 18± 19% walking.

Players executed 19± 22 sprints in a game (3%). Training

programmes should reXect these demands placed on players

during competition.

EV ects of exercise m ode on foot skin tem perature

A.J. Purvis and N.T. Cable



During intermittent exercise, there is an increase in core

temperature and skin temperature. However, little is known

about changes in skin temperature of the foot. This infor-

mation is of importance to footwear manufacturers and

players. The aim of this study was to establish changes in

foot skin temperature during continuous and soccer-speciW c

intermittent exercise.

Twelve participants exercised at the same overall intensity

for 20 min on a motorized treadmill following a soccer-speciW c

intermittent protocol (n = 6) or a continuous protocol (n = 6).

The intermittent protocol had previously been devised to

simulate soccer match-play (Drust, 1997: Unpublished

doctoral dissertation, Liverpool John Moores University).

Skin temperature was measured (using skin thermistors) at


three sites on the foot and four other sites on the body to

calculate a weighted mean skin temperature (Ramanathan,

1964: Journal of Applied Physiology, 19, 531). Baseline and end-

of-exercise skin temperatures were compared to determine

any eV ect of exercise mode using the Analysis of Summary

Statistics Test (Mathews et al., 1990: B ritish M edical Journal,

300, 230 ± 235).

SigniW cant diV erences (P < 0.05) over time were observed

in both exercise conditions for all foot sites but not mean skin

temperature. Using analysis of variance, a signiW cant dif-

ference between condition and duration (P < 0.05) was also

found for the foot. The mean skin temperature did not show

a signiW cant diV erence (P > 0.05) over time but did display a

statistically signiW cant diV erence between conditions.

We conclude that the foot displays a markedly diV erent

thermoregulatory response compared with the rest of the

body. There was a large increase in foot skin temperature

in both conditions and during intermittent exercise the

magnitude of this increase was enlarged.

Factors associated with pre-season W tness attributes

of rugby players

K.L. Quarrie and S. Williams

Injury Prevention Research Unit, University of Otago, Dunedin,

New Zealand

The aim of this study was to determine the factors associated

with the pre-season W tness attributes of rugby players.

Altogether, 258 male rugby players were enrolled in the New

Zealand Rugby Injury and Performance Project, a prospective

cohort study. Players completed a questionnaire that elicited

information about rugby playing and injury experience,

training patterns, and health and lifestyle factors. They also

underwent an anthropometric assessment and completed a

battery of physical performance tests.

A factor analysis of the data identiW ed two constructs

(endurance and speed/power). The variable that loaded most

strongly on each factor was selected as the dependent variable

for regression analyses. The 20 m multi-stage shuttle run test

was selected as the dependent variable for endurance and

a 30 m sprint from a 5 m running start was chosen as the

dependent variable for speed/power.

Fifty-three percent of the variance in number of aerobic

shuttles completed, and 43% of the variance in sprint

times, was explained by the regression analyses. The following

variables were associated with both aerobic endurance and

sprinting speed: standard of play, position, sum of six skin-

folds, self-rated rugby ability and ethnic origin (European or

Polynesian). Also associated with aerobic endurance were:

months of oV -season endurance training, self-rated health

status, hazardous alcohol use, trying to lose weight in the

oV -season, and cigarette smoking status. Having played repre-

sentative rugby during the previous season and current injury

status were other variables associated with sprinting speed.

New Zealand Maori and PaciW c Island players generally per-

formed better on measures of sprinting speed and worse on

measures of aerobic endurance than their European counter-

parts of similar standard and position. It would appear that to

ensure their W tness for rugby is optimal, players should choose

an appropriate position; try to maintain their lean body mass

at as high a level as possible; enter the season free from injury;

perform suY cient training in the oV -season; and abstain from

smoking cigarettes.

Should football players be m onitored continuously over

the season to assess overtraining?

P. Rainer

University College Worcester, Worcester, UK

As the Association Football season extends over 10 months of

the year, coaches are all too familiar with the case of excessive

training being characterized by long-lasting fatigue and

decline in competitive performance. Coaches face the problem

of separating the normal fatigue resulting from high-intensity

training or match-play from the underlying fatigue associated

with overtraining (Fry et al., 1992: Sports M edicine, 12, 32± 65).

The aim of this study was to design a battery of tests to

monitor players over a typical week in a competitive season

and to establish if these tests could distinguish between those

who were and were not `fatigued’ .

Eight university players performed a replicated W eld study

of a simulated football test of 30 ´ 6 s sprints preceded by a 60

s jog (40% max) and followed by a 54 s walk (20% max). The

participants completed three tests in 8 days, with baseline data

established 1 day before testing and repeated at days 9, 12 and

15 if symptoms were still evident. The experimental design

involved resting measures of blood lactate, blood pressure,

heart rate and basal metabolic rate on arrival, followed by

a 10 min submaximal run for measures of oxygen uptake,

heart rate after 5 and 10 min, recovery blood pressure (2 and

7 min) and recovery heart rate for 5 min. Following 10 min

recovery, the participants performed a maximal inter-

mittent sprint test (Lakomy, 1987: Journal of Physiology, 354,

33P). The participants also completed a daily analysis of the

demands of training (Eichner, 1995: Journal of Sports Sciences,

13, S41± S48).

The results indicated no signiW cant diV erences for resting

measures (P > 0.05); of the submaximal measures, only

heart rate after 10 min was signiW cantly decreased (P < 0.05).

Maximal lactate, peak power output and maximal heart rate

were decreased at day 9 (P < 0.05); peak power output

remained elevated at day 12. The fatigue index was also

increased, from 15.9% to 18.5% (P < 0.05), between day 1

and day 9.

Our results suggest that resting and submaximal measures

of physiological responses may be inappropriate for the

diagnosis of `fatigue’ . Tests of anaerobic power, employing

the muscular and neuromuscular patterns within the game,

may be the best indicators of imminent overtraining. In

support of the literature (Stone et al., 1991: Journal of Applied

Sport Science Research, 5, 35 ± 50), our results suggest that

athletes develop symptoms speciW c to the type of training

they perform and diagnosis of symptoms should not be

generalized.


The eV ect of carbohydrate supplem entation on the work

rate of Gaelic football players

T. Reilly and S. Keane



The fall in muscle glycogen concentrations towards the end

of endurance activities, including soccer match-play, is linked

to a fall in work rate (Saltin, 1973: Medicine and Science

in Sports and Exercise, 5, 137 ± 146). The shorter duration of

Gaelic football matches (60 min at club standard, 70 min for

inter-county championships) allows players to sustain activity

levels more easily, but it is not clear whether carbohydrate

supplementation is of beneW t in this sport as it is in soccer.

The aim of this study was to monitor the eV ect of ingesting

a 5% glucose solution on players’ work rates, including any

inXuence on fatigue.

Eight inter-county players underwent the experimental

treatment and their work rates were compared to those of

a reference group of 56 inter-county players. Work rate was

calculated according to Keane et al. (1993: Australian Journal

of Science and Medicine in Sport, 25, 100 ± 102) and broken

down into periods of 10 min. The glucose solution was

administered 10 min before competition (150 ml) and again

at half-time (150 ml). Players taking the energy drink had a

higher frequency of discrete activities and walked for a shorter

time during the game (35.4 vs 36.9% of total distance). A

reduction in distance covered in the W nal 10 min was evident

in both groups. These observations demonstrate that fatigue

that occurs towards the end of competitive Gaelic football

is not necessarily prevented by ingesting glucose solutions

before the match.

Seasonal variations in the W tness of elite Gaelic

footballers




Seasonal variations in W tness levels are anticipated to corre-

spond with the phases of the competitive season. Such cycles

in W tness characteristics have been described for soccer

(Thomas and Reilly, 1979: B ritish Journal of Sports M edicine,

13, 103 ± 109) and Rugby Union (Tong and Mayes, 1995:

Journal of Sports Science s, 13, 123 ± 127) players. In Gaelic

football, the major competition, the All-Ireland inter-county

championship, takes place in the summer, starting in May and

culminating in the All-Ireland W nal in September. The inter-

county League programme is held over the winter and spring

months. The aim of this study was to monitor W tness and per-

formance measures in elite Gaelic footballers over a complete

season.

A senior inter-county male squad (n = 32) was measured on

six occasions throughout the playing season from January to

September. The players undertook a systematic training pro-

gramme, on average three times a week, in addition to regular

competition with their club as well as the county team.

Anthropometric measures included body mass and percent

body fat, estimated from four skinfold thickness measures

(Durnin and Womersley, 1974: B ritish Journal of Nutrition,

32, 77 ± 97). The performance battery included sprints (in

football boots) over 50, 100, 200 and 400 m and a 12 min

run. Maximal oxygen intake (VÇ O 2max) was estimated from a

progressive 20 m shuttle run (Ramsbottom et al., 1988: B ritish

Journal of Sports M edicine, 22, 141± 144). A one-way analysis of

variance was used to examine changes in mean values for the

squad of players over the course of the season from Test 1

(January) to Test 6 (September). A least signiW cant diV erence

test was used to assess where speciW c diV erences lay.

Over the six tests there were improvements in the 50 m

(7.43 ± 0.2 to 6.56 ± 0.2 s), 100 m (15.3 ± 0.5 to 13.0 ± 0.5

s), 200 m (33.5 ± 0.9 to 30.4 ± 0.9 s) and 400 m (83 ± 2.4

to 73 ± 1.9 s) runs. Distance covered in 12 min increased

from 2633 ± 151 m to 3028 ± 114 m, but was shorter in

Test 2 than at other times (P < 0.05) and longer in Tests 3 and

4 than in the W rst two tests (P < 0.05). The VÇ O2max showed

a non-signiW cant change from 52.8 ± 2.1 to 53.3 ± 3.2

ml ´ kg - 1 ´min - 1. These changes were accompanied by an

average weight reduction of 3.3 kg (Table 1).

The main improvement in the W tness proW les of the players

was the reduction in sprint times over 50 to 400 m. This

improvement was associated with a reduction in body mass,

itself largely attributable to loss of body weight as fat. The

seasonal proW le provides a good baseline for the Gaelic football

players, as this team won the all-Ireland championship during

the year of the study. The improvements in the anaerobic

measures were not matched by their aerobic test counter-

parts. Performance in the 12 min run was enhanced by the

systematic training programme. The estimated VÇ O2max did

increase but the diV erence was non-signiW cant (P > 0.05).

For this measure, data were not obtained in the later stage of

Table 1. Test results for the inter-county squad for the entire season from January (Test 1) to September (Test 6) (mean ± s)

Test 1 Test 2 Test 3 Test 4 Test 5 Test 6

Body mass (kg)

Est. VÇ O2max (ml ´kg - 1 ´min - 1)

Cooper’ s 12 min run (m)

50 m sprint test (s)




86.0 ± 5.3

52.8 ± 2.1

2633 ± 151

7.43 ± 0.2

15.3 ± 0.5

33.5 ± 0.9

83 ± 2.4

85.7 ± 5.3

53.3 ± 1.9

2563 ± 117

7.19 ± 0.2

14.5 ± 0.5

33.7 ± 0.7

78 ± 2.7

85.1 ± 5.2

50.2 ± 3.5

3024 ± 90

6.95 ± 0.2

14.0 ± 0.4

31.3 ± 0.7

73 ± 2.1

84.4 ± 5.2

53.3 ± 3.2

3028 ± 114

6.96 ± 0.3

13.6 ± 0.4

32.7 ± 1.5

75 ± 2.9

82.9 ± 5.7

Ð

Ð

6.78 ± 0.2

13.4 ± 0.5

30.6 ± 1.1

76 ± 3.2

82.7 ± 5.0

Ð

Ð

6.56 ± 0.2

13.0 ± 0.5

30.4 ± 0.9

73 ± 1.9


the season before the major championship matches when the

aerobic W tness levels would be expected to reach their peak. It

should also be emphasized that not all players were able to

continue to improve during the course of the season, W tness

levels regressing when players were injured and had to reduce

their training load.

Estim ation of physiological strain on Gaelic football

players during m atch-play




The physiological strain induced in W eld games may vary

with the standard of competition. The heart rate response

to exercise provides a useful global measure of the exercise

intensity. Mean heart rate during the entire game has been

used as a measure of physiological strain, despite the inter-

mittent nature of the activity (Bangsbo, 1994: Acta Physio-

logica Scandinavica, 150 (suppl. 619), 1± 156; Reilly, 1997:

Journal of Sports Science s, 15, 257 ± 263). This applies to Gaelic

football as well as soccer among the football codes. The aims

of this research were to monitor heart rate during competitive

Gaelic football matches, to compare heart rate responses

between inter-county and senior inter-club matches, and to

establish the intensity of training matches compared with

inter-county competitive games.

Twenty senior inter-county and 13 senior club standard

players participated. Each wore a short-range telemetry

system (Seca Sportrance 300) during competitive matches.

The duration of the games was 60 min in all cases. Ten of the

inter-county players were later examined in training sessions

to establish the intensity of exercise relative to the competitive

matches. The maximal heart rates of the players were revealed

during performance of a 20 m progressive shuttle run to

estimate maximal oxygen uptake (Ramsbottom et al., 1988:

B ritish Journal of Sports M edicine, 22, 141 ± 144). Following

each game, data were downloaded and analysed by means of a

dedicated computer program. Mean heart rate was calculated

for each half of the match. A further analysis established the

times for which the heart rate lay within discrete ranges.

The average heart rate was 9 beats ´min - 1 higher for the club

players than for the inter-county players (Fig. 1). For the elite

players, mean heart rate did not vary between the 30 min

halves or between the W rst 10 min and the W nal 10 min of the

game. Heart rate was more variable for the club players, tend-

ing to increase as the game progressed. The groups attained

peak heart rates of 201 ± 16 beats ´min - 1 (elite) and 205 ± 13

beats ´min - 1 (club) during the match. These observations in

the elite players were only periodically approached in their

training regimens, when mean heart rate was 142 ± 6

beats ´min - 1 for 28% of the match time and 30% for training

(Table 1). The corresponding values for heart rates exceeding

180 beats ´min - 1 were 11% and 8% respectively.

Our results indicate relatively high physiological strain in

Gaelic football matches, approaching 80% maximum heart

rate on average. The lower intensity (albeit longer duration) of

training was due to the relatively smaller (27% vs 42%)

amount of time spent with heart rates between 161 and 180

beats ´min - 1. We conclude that Gaelic football, whether inter-

county or inter-club, represents strenuous exercise, whereas

training stresses can be described currently as moderate.

EV ect of an active warm -down following com petitive

soccer

T. Reilly and M. Rigby



Elite soccer players may be obliged on occasions to compete in

midweek between adjacent weekend matches. In such cases,

there can be residual eV ects of the previous games that cause

decrements in performance. It is necessary, therefore, to

attempt to accelerate the recovery from fatigue after a game

to prepare optimally for the ensuing match. The aim of this

study was to determine the eY cacy of an active warm-down

post-game in enhancing recovery processes in soccer players.

Fourteen university male soccer players (mean ± s: age

20.9 ± 1.5 years, height 175 ± 6 cm, body mass 77.5 ± 5.6 kg,

percent body fat 13.2 ± 2.7%) participated in the study, half of

whom undertook a 12 min warm-down after a match that

consisted of jogging and Xexibility exercises. The remaining

seven participants formed a reference group. All participants

completed a set of performance tests approximately 20 min

after the game and for the next 3 days at the same time of day.

The battery of tests included broad jump, vertical jump, 30 m

sprint and 7 ´ 30 m sprint fatigue test, while muscle soreness

was rated using a visual analog scale. Baseline measures were

taken before the experiment and the groups were matched on

the performance tests.

Figure 1. Heart rate during inter-county and inter-club matches

(mean ± s).

Table 1. Percent total time spent in various heart rate ranges by inter-

county players during matches and during training

Heart rate range

(beats ´min - 1) Match (%) Training (% )

<100

101± 130

131± 160

161± 180

>181

1.1 ± 1.0

17.8 ± 9.6

28.1 ± 11.8

42.5 ± 8.4

10.5 ± 14.5

4.3 ± 4.1

31.0 ± 7.0

30.0 ± 5.4

26.3 ± 9.0

8.4 ± 10.8


Both groups suV ered decrements in performance that

persisted for 2 days post-game for the 30 m sprint. The

declines were greatest in the reference group. The group who

had used warm-down had the lower soreness ratings and

recovered more quickly to meet their pre-game performance

measures after 3 days for both jump tests, and the sprint

fatigue test (all P < 0.05). We conclude that active warm-down

can have a beneW cial inXuence on recovery from a soccer

game. Furthermore, it would appear that 72 h are necessary

before players can completely regain their performance

capabilities after strenuous matches.

InX uence of playing position on W tness and

perform ance measures in female soccer players

T. Reilly and C. Wells



The aims of this study were to explore the existence of

positional diV erences in W tness and performance variables, and

to investigate the relationship between kick distance and peak

muscle torque at a range of angular velocities, among female

soccer players.

Forty-nine female soccer players of university standard

participated in the study. Their mean (± s) age was 19.0 ± 3.4

years, height 164 ± 9 cm and body mass 60.7 ± 5.0 kg. They

were self-classiW ed into 11 centre-backs, 10 full-backs, 17

midW eld players and 11 forwards. They participated in a series

of laboratory and W eld-based tests. The tests and methods

were as follows:

· Maximal oxygen uptake (VÇ O 2max): estimated from perfor-

mance in a 20 m shuttle run test.

· Repeated sprint test: 10 ´ 30 m with 20 s intervals.

· Anaerobic performance: estimated from vertical jump.

· Percent body fat: measured by bioelectrical impedance

(BodyStat, Douglas, Isle of Man).

· Peak torque, knee Xexion and extension: isokinetic, 1.05

and 3.4 rad ´s - 1 (Lido Active, Davis, CA, USA).

There was a signiW cant inXuence of playing position on

estimated VÇ O 2max (F = 9.84, P < 0.01). Follow-up tests

established that the diV erence lay between the midW eld

players (mean values of 48 ml ´ kg - 1 ´min - 1) and the centre-

backs (mean 43.7 ml ´kg - 1 ´min - 1).

The forwards were the fastest in the 30 m sprint test, but

diV erences from the other playing positions were non-

signiW cant according to the Kruskal-Wallis test (H = 1.63, P >

0.05). Performances over the 10 sprints displayed appreciable

fatigue (averaging 83.1% of initial best time), which did

not vary between positions (F = 1.10, P > 0.05). Similarly,

although vertical jump performance was best in centre-backs

and forwards (see Table 1), and poorest in full-backs and

midW eld players, the diV erences did not reach statistical

signiW cance (P = 0.13 and P > 0.05).

Central defenders were signiW cantly taller (F = 7.08,

P < 0.01) than full-backs and midW eld players (Table 2).

Forwards were intermediate and not signiW cantly diV erent in

height from any of the other groups. The central defenders

were also heavier than the midW eld players (F = 7.83, P <

0.01) and had the greatest fat-free mass. There was no signi-

W cant diV erence between the groups in percent body fat.

The values reported for peak torque during isokinetic

movements (Table 3) are for the 17 subjects who visited the

laboratory for these tests. The centre-backs had consistently

the highest values, being signiW cantly diV erent from full-backs

for concentric knee extension (F = 7.93, P < 0.05) at 1.05

rad ´s - 1 and for eccentric knee Xexion (F = 4.33, P < 0.10) at

the faster angular velocity. The centre-backs demonstrated

consistently higher values than the other players for the iso-

kinetic tests. Values were signiW cantly diV erent from those of

the full-backs for knee extension (concentric) at 1.05 rad ´ s - 1

(F = 7.93, P < 0.05) and Xexion (eccentric) at 3.14 rad ´ s - 1

(F = 4.33, P < 0.10).

SigniW cant correlations for the knee extensors were evident

between kick performance and peak torques during concentric

Table 1. Field test performances according to positional role (mean ± s)

Centre-back Full-back MidW eld Forward

Vertical jump (cm)

VÇ O2m ax (ml ´kg - 1 ´min - 1)

Sprint time (s)

Speed decrement (s)

35.4 ± 2.7

43.7 ± 3.0

4.81 ± 0.18

3.79 ± 0.56

34.6 ± 3.6

45.7 ± 2.3

4.86 ± 0.19

4.13 ± 0.38

35.0 ± 3.5

48.0 ± 1.8

4.84 ± 0.17

4.05 ± 0.37

35.2 ± 3.6

46.3 ± 1.7

4.80 ± 0.25

4.04 ± 0.54

Table 2. Anthropometric measures and kick performance of players (n = 49) according to

playing positions (mean ± s)


Height (cm)

Body mass (kg)

Fat-free mass (kg)

Body fat (%)

Kick distance (m)

167 ± 1

62.6 ± 2.0

47.1 ± 1.4

22.8 ± 1.4

27.8 ± 2.0

162 ± 3

59.9 ± 2.5

45.9 ± 1.6

24.2 ± 1.4

27.1 ± 2.2

162 ± 4

59.0 ± 2.8

45.5 ± 1.9

23.1 ± 1.4

27.1 ± 2.2

165 ± 2

61.7 ± 2.7

46.6 ± 0.9

24.9 ± 1.1

26.7 ± 2.3


Table 3. Peak torque for knee Xexion and extension at two angular velocities (mean ± s)


Knee extension

Con 1.05 rad ´ s - 1

Ecc 1.05 rad ´s - 1

Con 3.14 rad ´ s - 1

Ecc 3.14 rad ´s - 1

109 ± 2.1

123 ± 9.8

76.6 ± 7.0

106 ± 8.5

96.7 ± 2.1

117 ± 10.0

72.3 ± 5.1

101 ± 2.1

106 ± 5.3

120 ± 5.3

75.8 ± 7.4

102 ± 4.0

105 ± 2.5

118 ± 6.3

72.5 ± 2.0

102 ± 3.3

Knee X exion

Con 1.05 rad ´ s - 1

Ecc 1.05 rad ´s - 1

Con 3.14 rad ´ s - 1

Ecc 3.14 rad ´s - 1

50.4 ± 7.1

55.4 ± 9.5

45.4 ± 5.3

50.8 ± 7.2

42.0 ± 2.7

49.0 ± 1.0

35.0 ± 1.7

37.0 ± 1.0

50.0 ± 5.5

54.6 ± 7.9

40.0 ± 6.6

46.6 ± 5.6

47.7 ± 4.4

51.2 ± 3.0

43.0 ± 2.9

44.8 ± 3.2

actions (r = 0.62 and 0.55 at 1.05 and 3.14 rad ´ s - 1, respec-

tively) and for eccentric actions (r = 0.75 and 0.59 for the

respective angular velocities of 1.05 and 3.14 rad ´ s - 1). The

correlation coeY cient between fat-free mass and kick distance

was 0.69. The correlation coeY cients for the knee Xexors were

consistently lower than these values, being 0.52 and 0.49 for

concentric and 0.47 and 0.43 for eccentric actions at 1.05 and

3.14 rad ´s - 1, respectively.

The main observations in this study were: (1) positional

diV erences among female soccer players were evident in body

size and aerobic power variables; (2) these diV erences were not

evident in anaerobic and repeated sprint tests, or in body com-

position; and (3) muscle strength measures were signiW cantly

correlated with kicking performance, partly inXuenced by fat-

free mass.

Prelim inary investigation of the seasonal birth

distribution of England World Cup cam paign players

(1982 ± 98)

D.J. Richardson and G. Stratton



Theoretically, the date of birth of international soccer players

should be evenly spread throughout the year. Early maturing

children or those born early in the academic or competition

year (i.e. September to December) may have initial advan-

tages in power, speed and strength. Brewer et al. (1995: Sports

Exercise and Injury, 1, 154± 157) reported that over 50% of

England under-16 youth internationals had their birthdays

between September and December. The complexity and

speculative nature of talent detection and development has

previously been recognized (Regnier et al., 1993: In A Hand-

book of Research on Sport Psychology, edited by R.N. Singer,

M. Murphey and L.K. Tennant, pp. 290 ± 313. New York:

Macmillan). There are a number of prerequisites for football

success (e.g. technique, determination, intelligence, speed). It

would appear that, at youth international standard, the less

mature players are not selected. One would assume that by full

maturity there would be an even balance between the birth

dates of `elite’ players across the year. The aim of this study

was to establish the distribution of birth dates, in relation to

the academic and competition year, for full England inter-

national Association Football players.

The birth dates of senior England players (n = 139) involved

in World Cup campaigns (i.e. qualifying matches and tourna-

ments) since 1982 were analysed. Players were placed into

one of three categories according to their date of birth

(September± December, January± April, May± August), and

four categories according to their primary playing position

(goalkeeper, defence, midW eld, forward).

A signiW cant diV erence (x22 = 17.703, P < 0.01) was evident

between the dates of birth of the players. Fifty percent of

players had birthdays between September and December,

compared to 28% between January and April and 22%

between May and August. Figure 1 shows that this trend was

consistent throughout each of the campaigns since 1982.

Figure 2 highlights the diV erences across playing positions.

Sixty-nine percent of goalkeepers, 51% of forwards and 48%

of defenders had their birthdays between September and

December. The birth dates for midW eld players were more

evenly spread across the three calendar periods: 44%, 21% and

36% respectively.

The results indicate an over-representation of elite players

with birthdays between September and December. These

results are in line with those of Dudink (1994: Nature, 368,

592), who reported that signiW cantly more English and Dutch

Figure 1. Birth dates for England World Cup campaign players

(1982± 98).


football league players were born in the W rst quarter of

their respective competition year (P < 0.001). On the basis of

probability, there should be an equal distribution of players’

birth dates at full maturity. The trend indicates a bias towards

the `early bird players’ (i.e. born early in the academic and

competition year) during the identiW cation and selection pro-

cess. This may be from as early as 8 years of age, thus giving

them a `head start’ over other players. These players may be

exposed to higher playing standards and better coaching, and

therefore more likely to graduate to the elite level, than late

maturing players. Coaches and teachers must develop a

greater understanding of the growth and development of

young footballers to redress this imbalance in future.

In conclusion, there was an over-representation of England

World Cup campaign players (1982 ± 98) born early in the

academic and competition year (i.e. September through

December). The discrimination eV ect was greater for goal-

keepers, forwards and defenders. Talent identiW cation and

selection procedures must place more emphasis on talent and

less reliance on physical attributes (i.e. size and strength).

EV ects of b-hydroxy b-m ethylbutyrate on muscle

metabolism during resistance exercise training in

Rugby Union players

W.J. Sambrook, D. Kellett and I. McDowell

University College Chester, Chester, UK

The proposed anabolic eV ects of the leucine metabolite b-

hydroxy b-methylbutyrate (HMB), previously shown to occur

in untrained individuals by Nissen et al. (1996: Journal of

Applied Physiology, 81, 2095 ± 2104), have not been shown to

occur in resistance-trained individuals, for whom the eV ects of

continuing resistance training are not as great as the initial

eV ects of resistance training in untrained individuals (Enoka,

1988: Sports M edicine, 6, 146 ± 168). The eV ects of dietary

supplementation with HMB were thus studied in 12 male

Rugby Union players who were randomly allocated, using a

double-blind design, to the supplementation of either 1.5 g

HMB or 1.5 g of a carbohydrate placebo of dextrose mono-

hydrate. The subjects were required to consume the 1.5 g

dose daily while following a resistance training programme,

involving three sessions per week of 80 min duration, for 4

Figure 2. Birth dates of England World Cup campaign players

(1982 ± 98) with respect to their primary playing position.

weeks. Fortnightly tests included those for body composition,

muscle girth, lactate dehydrogenase (LDH) activity and

creatine phosphokinase (CPK) activity. The HMB group

signiW cantly decreased the level of fat mass (P < 0.05) and also

substantially decreased the activity levels of both the muscle

enzymes CPK and LDH (P < 0.001). However, the mean lean

muscle mass increase of 1 kg in the HMB supplemented group

was not statistically signiW cant (P > 0.05). We conclude that

the supplementation of 1.5 g of HMB per day inhibits the

normal rate of muscle protein breakdown, and that although

it does not lead to a signiW cant increase in lean muscle mass,

it may lead to an increase in the rate of body fat loss in

resistance-trained Rugby Union players.

Dietary analysis of English women soccer players

D. Scott, P.J. Chisnall and M.K. Todd


Girls’ and women’ s soccer is enjoying a period of un-

precedented popularity in England, with 29,000 females

currently registered with clubs (English FA, 1998: Talent and

Development Plan. London: FA). Soccer participation results in

an increased energy demand which must be matched by an

increased energy intake to maintain performance and desired

body weight. The nutritional requirements and habits of male

soccer players have been extensively researched, but little

information with regard to women soccer players is available.

The aim of this study was to examine the dietary habits of

26 Premier Division (DP) players (22.2 ± 6.2 years) and 46

National Division One (D1) players (22.8 ± 6.0 years).

Players recorded all food and drink consumed over two

consecutive days using food diaries before a team training

session. Height, body mass and skinfold thicknesses were

measured on all players upon collection of the food diaries.

Physical characteristics of the two groups of players were

similar, with no signiW cant diV erences (P > 0.05) in age, body

mass, height or percent body fat.

There were no signiW cant diV erences (P > 0.05) between

the intakes, relative to body weight, of daily energy (DP vs D1:

121 ± 47 vs 125 ± 41 kJ ´ kg - 1), carbohydrate (3.9 ± 1.2 vs

3.7 ± 1.2 g ´kg - 1), protein (1.0 ± 0.4 vs 1.1 ± 0.4 g ´ kg - 1),

fat (1.0 ± 0.5 vs 1.2 ± 0.7 g ´kg - 1), or the absolute amounts

of alcohol (0.9 ± 3.9 vs 13.0 ± 23.4 g) consumed. When

expressed as a fraction of total energy intake, mean carbo-

hydrate intake was signiW cantly higher (P < 0.05) for Premier

players (54.6 ± 5.9 vs 47.5 ± 9.8%). In addition, both groups

consumed mean iron intakes 40% below the reference nutri-

ent intake of 14.8 mg ´day - 1. Brewer (1994: Journal of Sports

Sciences, 12, S35± S38) suggested that female soccer players

consuming energy intakes greater than 188 kJ ´ kg - 1 ´ day - 1

should derive a minimum of 55% of total energy intake from

carbohydrate. Additionally, Economos et al. (1993: Sports

Medicine , 16, 381 ± 399) recommended that for female players

consuming less than 188 kJ ´kg - 1 ´ day - 1, carbohydrate con-

sumption should be a minimum of 6 g ´kg - 1 ´day - 1. From the

results obtained, it is clear that some players consume a diet

which supplies less carbohydrate than recommended to sus-

tain performance in training and competition.


Table 1. Physical characteristics of Brazilian soccer players

Professional Junior Juvenile

(n = 27) (n = 42) (n = 19)

Age (years)

Height (cm)

Body fat (%)

VÇ O2max (ml ´kg - 1 ´min - 1)

VÇ O2max (ml ´kg - 0.75 ´min - 1)

Treadmill exercise (s)

AT-VÇ O2 (ml ´kg - 1 ´min - 1)

v-AT (km ´h - 1)

AT-%VÇ O2max

24.18 ± 4.06

179 ± 6

7.89 ± 2.91

52.52 ± 7.49

154.45 ± 21.41

938.61 ± 69.03

42.61 ± 6.15

13.65 ± 1.21

81.37 ± 7.10

18.95 ± 1.16a

177 ± 6

6.78 ± 1.94

62.10 ± 6.09a

180.27 ± 17.15 a

981.07 ± 34.82a

50.61 ± 5.74a

13.93 ± 1.07

80.64 ± 5.26

16.94 ± 0.55a ,b

176 ± 6

7.53 ± 3.91

65.97 ± 4.81a

188.48 ± 13.14 a

958.77 ± 48.50

56.17 ± 3.67a ,b

14.50 ± 0.74a

84.98 ± 4.43b

a SigniW cantly diV erent from the professionals: P < 0.05.b

SigniW cantly diV erent from the juniors: P < 0.05.

Decrease in aerobic power and ànaerobic threshold’

variables with age in Brazilian soccer players

S.G. da Silva, L. Kaiss, W. Campos and I. Ladewig

Physical Education Department, Universidade Federal do Paran…, B rasil

The aim of this study was to identify diV erences in anthropo-

metry, maximal oxygen consumption (VÇ O 2max) and ̀ anaerobic

threshold’ among soccer players of diV erent age groups.

We studied 88 athletes: 19 juveniles, 42 juniors and 27

professionals. The following variables were assessed: height,

body mass, percent body fat, maximal oxygen uptake

(VÇ O2max), time to exhaustion on the treadmill and anaerobic

threshold (AT) (expressed in terms of VÇ O2, %VÇ O 2max and

velocity on the treadmill). The results are shown in Table 1.

We conclude that with increasing age and years of soccer

practice, there is a decrease in running velocity and VÇ O2 at

the ànaerobic threshold’ in Brazilian soccer players.

Fitness characteristics of English women soccer

players

M.K. Todd, D. Scott and P.J. Chisnall


Over the last 10 years, the number of formally organized

women’ s football clubs in England has grown from 263 to

700, and the number of registered players has doubled from

7000 to 14,000. Although much literature exists providing

information on male soccer players, there is a shortage of

information available on female players. A cohort of English

women players (age 22.9 ± 5.9 years; n = 120) from 10 clubs

in both the National Premiership and two regional leagues

were tested for measures of physical W tness. All clubs were

visited within 2 weeks of the last game of the season while

regular training was ongoing and players were measured for

anthropometry, endurance, strength, speed and Xexibility.

Pearson correlation analysis revealed relationships between

the 30 m sprint and a number of other variables, including 5 m

sprint (r = 0.79, P < 0.01), % body fat (r = 0.54, P < 0.01),

vertical jump (r = - 0.55, P < 0.01), endurance performance

(r = - 0.46, P < 0.01) and body mass (r = 0.30, P < 0.01).

Other relationships were found to exist between % body fat

and the following variables: vertical jump (r = - 0.35, P <

0.01), endurance performance (r = - 0.50, P < 0.01) and 5 m

sprint time (r = 0.52, P < 0.01). The deleterious eV ect of

age on performance was revealed by signiW cant positive cor-

relations (P < 0.05) with 30 m sprint time (r = 0.24), % body

fat (r = 0.22) and vertical jump (r = - 0.23), although Xexibility

(r = 0.28, P < 0.05) and leg strength (r = 0.23, P < 0.01)

correlated favourably with ageing. Using t-tests, we revealed

diV erences between Premier League players (n = 61) and

regional league players (n = 58) for % body fat (t = - 3.03,

P < 0.01) and vertical jump (t = 2.27, P < 0.05). When players

were further divided into subgroups of recent international

representation (n = 25), Premier League players (n = 44) and

regional players (n = 51), % body fat correlated with playing

standard (rs = 0.27, P < 0.01); analysis of variance with Tukey

HSD post-hoc tests revealed diV erences in % body fat between

internationals and regional players (F2,115 = 5.0, P < 0.05).

Positional diV erences between goalkeepers (n = 9), defenders

(n = 45), midW elders (n = 44) and forwards (n = 24) were

analysed using analysis of variance, which revealed diV erences

in 30 m sprint time between goalkeepers and forwards (F3,106 =2.4, P < 0.05). Anthropometric diV erences were found for

body mass (F3,114 = 6.5, P < 0.05) between goalkeepers and

midW elders, and between goalkeepers and forwards; and for

height (F3,114 = 5.5, P < 0.05) between goalkeepers and mid-

W elders, between goalkeepers and forwards, and between

defenders and midW elders.

Results indicate that % body fat, speed (30 m sprint time)

and the èxplosive’ application of power (vertical jump height)

are important variables in player standard and should be

addressed in training regimens.

Som atotype characteristics of young soccer players

M. Toteva

National Sports Academy, SoW a, Bulgaria

The aims of this study were to compile a somatotype proW le of

young soccer players and to establish the speciW c changes in


somatotype that occur during growth. The participants were

80 young soccer players aged 12± 17 years from various sports

schools. The method of Heath and Carter (1992) was used for

somatotyping. The participants were classiW ed by age into six

groups, at intervals of 1 year. At the age of 12 years, players

have a mean mesomorph-ectomorph (1.86 ± 4.52 ± 4.27) pro-

W le. At 13 years of age, players become ecto-mesomorphic

(1.63 ± 4.66 ± 4.00). Ecto-mesomorphy was also found in the

other age groups: 14 years (2.08 ± 4.92 ± 3.17), 15 years (2.25 ±

5.05 ± 3.00), 16 years (2.40± 4.85 ± 3.20) and 17 years (2.30 ±

4.92 ± 3.25). We conclude that age has an eV ect on somato-

type in young soccer players as a result of changes during

adolescence and increases in muscle mass, especially in the

lower extremities. Our results can be applied to the morpho-

logical control of young soccer players and could be used in

W nal selection.

The running economy in early and late m aturing youth

soccer players

B. Van Renterghem, M. Janssens, D. De Clercq, J. Vrijens,

I. Duwez, M. Van Severen and A. Van Dijk

Department of Movement and Sport Sciences, University of Ghent,

B elgium

In youth soccer competitions, boys of the same age category,

but of diV erent maturity, play their games against and with

each other. Often, early maturing players are preferred by

the coach because they are taller, heavier and more power-

ful. The aim of this study was to identify diV erences in run-

ning capacity, especially running economy, between early

and late maturing pubertal soccer players of the same age.

Running economy is deW ned as the relative oxygen uptake

at a submaximal velocity, expressed in ml ´min - 1 ´ kg - 0.75

(as proposed by Bergh et al., 1991: Medicine and Science in

Sports and Exercise, 23, 205 ± 211). In other words, one runs

economically if the relative VÇ O 2 is low at a certain sub-

maximal velocity.

Fourteen young well-trained soccer players, aged 13 : 5±

14 : 10 years : months volunteered to participate in the study.

They were selected from a larger group, based on their

skeletal age. Seven of them could be considered early matur-

ing (skeletal age ³ calendar age + 1 year) and seven late

maturing (skeletal age £ calendar age - 1 year). Oxygen

uptake, CO 2 production and ventilation were determined

during a treadmill test at three submaximal velocities (8,

9.5 and 11 km ´h - 1). Stride frequency and stride length were

determined. The running movement was W lmed laterally,

revealing vertical oscillation of the body’ s centre of gravity

and sagittal plane kinematics. Height, body mass, leg

length, lower leg length, upper leg girth and calf girth were

measured.

Late maturers consumed signiW cantly less oxygen than early

maturing players at the same submaximal treadmill velocity.

Some anthropometric diV erences, a larger relative stride

length (= stride length ´ leg length - 1) and a diV erent movement

pattern of the swinging leg are the main explanatory factors for

this unexpected W nding.

PART II: BEHAVIOURAL ANALYSIS

Goal-scoring patterns over the course of a m atch:

An analysis of the Australian National Soccer

League

G.A. Abt, G. Dickson and W.K. Mummery

Central Queensland University, Rockhampton, Australia

Is goal scoring a purely random act, or is there a pattern which

emerges over the course of a match? Despite the apparent

random nature in which soccer matches are played, time

and motion analyses have revealed a more structural frame-

work of team play and game strategy. In this context, match

analysis has allowed coaches and scientists to quantify a

number of parameters, including the physiological demands

of play and individual player performance, leading to more

appropriate soccer-speciW c training and testing programmes.

It is against this background that an analysis of the time at

which goals are scored in the Australian National Soccer

League was undertaken. The results of this study were seen to

have implications for both coaching and W tness programmes.

Previous research has identiW ed a trend towards more goals

being scored towards the end of play (Morris, 1981, cited

in Ridder et al., 1994: Journal of the Amer ican Statistical

Association, 89, 1124± 1127; Reilly, 1996: In Science and Soccer,

edited by T. Reilly, pp. 65± 81. London: E & FN Spon).

Four seasons of matches (1994± 95 through 1997 ± 98) were

analysed, with the time at which each goal was scored being

recorded. Results revealed a systematic increase in the number

of goals scored as time progressed, which is most noticeable

when expressed per 15 min period. Goals scored during

each of the six 15 min periods were 262, 290, 331, 363, 390

and 429 goals, respectively. These results conW rm previous

research showing an increase in the number of goals scored

as a match progresses. This suggests either a fatigue factor,

particularly among defenders, or that teams gradually dis-

cover, and thereby exploit, the tactical characteristics of their

opponents.

The eV ects of age and skill on m otor and cognitive

components of soccer perform ance

W. Campos, S.G. da Silva and I. Ladewig

Universidade Federal do Parana, B razil

The aim of this study was to determine the eV ects of age

and skill on soccer knowledge and decision-making ability

of young soccer players. Wall volley and soccer dribble tests

were used to classify participants aged 8± 10 and 12± 14 years

as skilled and unskilled soccer players. The components

of performance analysed were declarative and procedural

knowledge, kick knowledge and videotape soccer decision-

making. Two-way analyses of variance (age ´ skill) were

calculated on the scores of the dependent measures. As

expected, independent of age, skilled players exhibited better

performance on soccer declarative knowledge (F1,47 = 36.12,

P < 0.05), soccer procedural knowledge (F1,47 = 17.88, P <


0.05), kick knowledge (F1,47 = 280.41, P < 0.05) and decision-

making ability (F1,47 = 40.12, P < 0.05). These W ndings

suggest that younger skilled children can perform similarly to

older children if they are equally skilful. The opportunity to

practise and to learn motor and cognitive skills in soccer was

more important than a child’ s age. The results suggest a strong

relationship between soccer skill, soccer knowledge and soccer

decision-making ability.

Activity proW le of elite soccer referees during

com petitive m atches

C. Castagna and S. D’ Ottavio


Rome, Italy

Few studies have been devoted to the performance of soccer

referees. The aim of this study was to compile an activity

proW le of elite soccer referees during match-play (Italian First

Division) to devise speciW c training methods. Thirty-three

referees were observed with trigonometry (Play ControllerTM)

a minimum of one and a maximum of six times during regular

season matches (n = 96). The mean (± s) distance covered was

11,469 ± 983 m (range 7818 ± 14,156 m). Although the length

of the two halves was not statistically diV erent (P > 0.40),

during the second half referees covered less distance (5612 ±513 vs 5854 ± 533 m, P < 0.0000001). Unorthodox direc-

tional modes distance (Reilly and Bowen, 1984: Perceptual and

M otor Skills, 58, 149 ± 150) decreased in the second half from

552 ± 280 to 433 ± 245 m (P < 0.0000001). Referees stood

still longer during the second half (392 ± 152 vs 447 ± 150 s,

P < 0.0000001). Distances covered at speeds more than 18.1

km ´h - 1 did not diV er signiW cantly between halves (1008 ±311 vs 989 ± 308 m, P > 0.39). However, distance covered at

speeds more than 24 km ´h - 1 increased in the second half from

202 ± 164 to 225 ± 158 m (P < 0.02). We conclude that, like

players of similar standard, referees appear to spare energy

during a match allowing them to perform high-intensity

activity when necessary. This strategy probably stems from

the experience gained through years of competition. The W t-

ness of referees may play an important role in the amount of

energy exerted in high-intensity activities.

How good are elite soccer referees? Just ask the players

and coaches!

S. Dickson

University of New England, Armidale, Australia

An uneasy relationship exists between players and coaches,

and sports oY cials. Many reasons have been oV ered in

explanation (see Dickson and Webb, 1998: Sports Coach, 20,

28 ± 29); it is unclear if perceived diV erences in the quality of

refereeing contribute to the divide between the two groups.

We hypothesized that the perceived quality of refereeing is sig-

niW cantly diV erent between players and coaches (as one group)

and oY cials (as a second group). Thirty-seven refereeing

skills, established as essential to eV ective refereeing per-

formance, were submitted to a sample of 173 Australian

National Soccer League game participants (players and

coaches, n = 110) and oY cials (referees, assistant referees

and referee inspectors, n = 63). The participants were asked

to indicate, on a 5-point Likert scale, how well each skill is

performed by referees during National League W xtures. Case

estimates for each participant were obtained using Rasch

latent trait scaling techniques. The estimates were subse-

quently submitted to one-way analysis of variance, which

indicated a signiW cant diV erence between the two groups

(F = 66.6, P < 0.0001). The skill of `distinguishing between

the severity of fouls’ is implicated, together with a number

of other skills, in causing this diV erence. Inspection of the

mean values for each group suggested the oY ciating group

viewed the quality of refereeing performance higher than the

participant group. With the quality of refereeing continually

under debate, it may be prudent to include systematic player

and coach referee-evaluations to improve the overall standard

of refereeing.

Investigating skills in oY ciating: Soccer ± a case

study

S. Dickson

University of New England, Armidale, Australia

The recent soccer World Cup in France highlighted one of the

most perennial and discussed problems in elite football ± the

quality of refereeing. This problem is exacerbated by an overall

lack of understanding about the precise nature of the referee’ s

role, together with the ambiguous contexts in which referees

make decisions. SpeciW cally, it is unclear which skills con-

stitute eV ective refereeing, and which of these skills are the

most important to the referee ’ s role. A hybrid form of the

Behaviourally Anchored Rating Scale was implemented to

identify the skills required by elite soccer referees. Two `expert

panels’ undertook a day-long process to identify which

skills were essential to refereeing National League soccer

in Australia. Thirty-seven skills were identiW ed, ranging from

decision-making to mental preparation skills. All skills

were expressed in behavioural terms to avoid ambiguity. To

validate the importance of each skill, a sample (n = 173)

of National League referees, assistant referees, referee

inspectors, players and coaches were asked to assess, on a

5-point Likert scale, the importance of each individual

skill. The data were analysed using Rasch latent trait scaling

techniques. This analysis clearly showed that a hierarchy of

importance was evident (separation index = 0.89), with the

most important skills encompassing rule interpretation and

consistency of decisions. The implications of this research are

three-fold: W rst, the skills required by referees are expressed

in unambiguous, observable behaviours; secondly, a clear

discrimination regarding the importance of each skill is

empirically established; and, thirdly, as a consequence of the

second point, training and assessment procedures can be more

accurately focused.


Activity proW le of young soccer players during

match-play



Rome, Italy

Data on activity patterns of soccer players almost all relate to

players older than 18 years of age. The aim of this study was to

determine the work-rate proW le of 12 young soccer players

aged 11.8 ± 0.6 years (mean ± s) in an attempt to devise

training strategies. The activity of the players was monitored

using trigonometry (Play ControllerTM) during 12 oY cial

eleven-a-side matches (halves lasting 30 min) on a regular

soccer pitch.

The total distance covered was 6175 ± 18 m. During the

second half, players covered 5.53% less ground (P > 0.05). At

speeds between 13.1 and 18.0 km ´h - 1, players covered 12.5%

less ground during the second half (P < 0.05). The players

stood still 10.9% of playing time (379 ± 109 s). Overall,

33.2 ± 4.3 bouts (range 28± 41) of 2.29 ± 0.65 s duration were

performed at speeds of more than 5 m ´ s - 1; the time between

bouts was 119 ± 20.5 s. Players stood still longer in the second

half (second vs W rst half: 229 ± 76 vs 173 ± 61 s, P < 0.05).

Players tended to play in restricted areas of the pitch and spent

8.97% of match-play performing high-intensity activities,

similar to the pattern reported for adult players (Bangsbo

et al., 1991: Canadian Journal of Sport Science s, 16, 110 ± 116).

To promote more active coverage of the pitch by young

players, at least of the age considered here, the dimensions of

the pitch and the number of players per side should be

reduced. The W tness of young players should preferably be

developed in games with a small number of players on each

side, thus maintaining motivation and promoting a more

active role in playing the game.

Match-to-m atch variations in work rates am ong elite

soccer referees



Rome, Italy

It has been reported that, despite signiW cant match-to-match

variations in total distance covered, the distance covered at

high speeds remains fairly constant among elite soccer players

(Bangsbo et al., 1991: Canadian Journal of Sport Sciences, 16,

110 ± 116). The aim of this study was to establish if this is also

the case with elite referees.

Using trigonometry (Play ControllerTM), 14 Italian referees

were observed during 65 First Division matches a minimum

of three and a maximum of six times. For comparison,

the matches with the shortest and longest distances covered

by each referee were subjected to analysis. The mean (± s)

shortest and longest distances covered were 10,949 ± 1095

and 12,303 ± 666 m respectively (P < 0.001), although the

mean duration of matches did not diV er signiW cantly

(P > 0.05). During matches in which the longest distance was

covered, the referees stood still 44% less time (P < 0.004)

and covered 10% more ground at low speed (P < 0.03) than

during matches in which the shortest distance was covered.

The distance covered at high speed (more than 18.1 km ´h - 1)

was not signiW cantly diV erent between the matches in which

the longest and shortest distances were covered (P > 0.05).

Our results suggest that, regardless of the length of a match

or the total distance covered, referees are fairly constant in

terms of high-speed activity ( > 18.1 km ´h - 1). Therefore, it

would appear that the diV erences between the two conditions

(shortest and longest distance covered) were a result of the

amount of low-intensity exercise or time spent standing still.

More research is required to verify whether this phenomenon

is related to the W tness of referees or to other factors.

Analysis of goals scored in the 1998 World Cup

A.G. Grant, A.M. Williams and T. Reilly



The soccer World Cup provides an opportunity to examine

the best teams and players in the world. An analysis of

how goals are scored can reveal critical factors that help

determine the most appropriate attacking strategy, as well as

developing individual goal scoring techniques. Several key

aspects of match-play were analysed and the results compared

with World Cup research. The variables examined included:

the time of goals scored, the build-up to goals, the techniques

used to score goals, the number of touches on the ball by

the goal scorer, the area of regained possession resulting in

goals, the number of passes before goals were scored, the time

of possession before goals were scored, and the breakdown of

set-play goals.

Altogether, 171 goals were scored in the 64 matches played

in the 1998 World Cup, an average of 2.67 goals per game.

More goals were scored in the W nal 15 min of match-play

than in other 15 min periods, similar to previous World Cup

W ndings. A comparatively large number of goals were scored in

the W rst 3 min of the second half and in W rst-half injury time.

Set-play goals accounted for 24.6% and open-play goals 63.2%

of goals scored. The most frequent techniques used to score

goals were with the inside and instep of the foot, the instep

being used for almost half of the 108 goals scored from open

play. There was a reduction in headed goals compared with

the 1990 World Cup, suggesting a change in playing style

towards controlled possession play as opposed to more `risky’

crosses and long passes. Only 10.4% of goals were scored from

outside the penalty box compared with almost 20% in the

1994 World Cup. More than 50% of goals scored from open

and set play involved a one-touch W nish. However, 16.7% of

goals from open play were scored with four or more touches,

reXecting the importance of players who can dribble or run

with the ball to create a goal-scoring opportunity. Similarly,

individual play was a key event in 20% of goals scored from

open play. Passing was implicated in 47.2% of goals scored

from open play. During open play, more goals came from

possession regained in the defending rather than the attacking

area. The mode for the number of passes before goals from

open play was three (21.3%) and 6± 10 s was the most frequent


duration in possession that preceded a goal (25.9%). Of the

42 goals scored from set plays, 50% were from free kicks,

47.6% from corner kicks and 2.4% from a throw-in. The

circumstances from which goals arise are varied and are likely

to be more complex than implied in a single deterministic

model.

An analysis of the successful and unsuccessful teams

in the 1998 World Cup

A.G. Grant, A.M. Williams and T. Reilly



The aim of this study was to diV erentiate between successful

and unsuccessful teams in the 1998 soccer World Cup by

analysing their performance on several aspects of match-play.

`Successful’ teams were deW ned as those that reached the

semi-W nals, while teams that failed to progress to the second

round were classiW ed as `unsuccessful’ . In total, 30 matches

were analysed. The successful teams averaged more attempts

at goal per game (18.1 vs 9.5) from shots, headers and free

kicks than unsuccessful teams. Successful teams performed

more passes per game (362.7 vs 308.9) and crossed the ball

more frequently (19.1 vs 12.7) than their unsuccessful

counterparts. They also ran and dribbled with the ball more

frequently. Successful teams performed considerably more

passes per game in the central attacking areas of the pitch.

Furthermore, they played more passes within the penalty box

(2.5 vs 0.8), as well as in the central area immediately outside

the penalty box (25 vs 15.4), compared with unsuccessful

teams. Successful teams were able to penetrate the defence by

passing, running or dribbling the ball in a forward direction

for longer sequences of play (93.5) compared to unsuccessful

teams (76.4). Finally, successful teams had more attempts at

goal in open play arising out of build-ups that involved four

passes or more and lasted for over 15 s, which highlights their

ability to create chances while maintaining possession. Our

observations indicate that the performance proW les as a whole

of successful teams (irrespective of goals scored) distinguish

them from the proW le exhibited by the less successful teams.

Physiological and technical analysis of eleven-a-side

and eight-a-side youth soccer m atches

A.G. Grant, A.M. Williams, R. Dodd and S. Johnson



The aim of this study was to establish the physiological and

technical demands of eight-a-side and eleven-a-side soccer.

Elite under-12 matches were recorded using two video

cameras. One camera followed an individual player for the

entire match (i.e. motion analysis), while a second camera

focused on the ball and its associated actions (i.e. match

analysis). Motion analysis revealed that, in eleven-a-side

matches, midW elders covered greater distances and had less

touches of the ball compared with eight-a-side matches; in

eight-a-side matches, forwards covered greater distances than

in eleven-a-side matches (P < 0.05). Match analysis showed

signiW cant diV erences in favour of eight-a-side matches in the

total number of passes (xÅ = 1105 vs 853), percent successful

passes (xÅ = 63.7 vs 48.5%), number of consecutive passes

(xÅ = 4.0 vs 2.7), number of crosses (xÅ = 26.7 vs 17.5), number

of goal attempts (xÅ = 28.8 vs 13.3) and number of goals scored

(xÅ = 4.0 vs 1.8) (P < 0.05). There were more changeovers of

possession (xÅ = 197 vs 133) and the ball was out of play

for longer (xÅ = 43.1 vs 26.2%) in eleven-a-side compared

with eight-a-side matches (P < 0.05). In conclusion, eight-a-

side matches provided players with more involvement and

encouraged more inventive attacking play.

M otivational proW les in Rugby Union

K. Hodge

School of Physical Education, University of Otago, Dunedin, New Zealand

The main aim of this study was to examine motivational `pro-

W les’ of goal orientations in Rugby Union. The participants

were 257 male Rugby Union players aged 20.6 ± 3.6 years

(mean ± s), with 6.3 ± 2.8 years of playing experience. They

were assessed on the following psychological variables: (1)

goal orientations (TEOSQ; Duda and Nicholls, 1992: Journal

of Educational Psychology, 84, 290 ± 299), (2) perceived ability/

perceived competence and (3) self-concept of physical ability.

ConW rmatory factor analysis conW rmed the two-goal model

underlying the TEOSQ (x264 = 91.56, P < 0.014; adjusted

goodness-of-W t index = 0.957, root mean square = 0.052)

for rugby players. Cluster analysis identiW ed homogeneous

goal proW le groups that diV ered signiW cantly on both the task

and ego subscales. Cluster analysis also generated `medium’

groups for both the task and ego subscales, but no extreme

group proW les emerged (i.e. high-task/high-ego or low-task/

low-ego). DiV erences in group proW les on the dependent

measures revealed that clusters 1 (medium-task/low-ego)

and 4 (medium-task/medium-ego) were signiW cantly lower in

`self-concept of physical ability importance’ than cluster 3

(medium-task/high-ego). The results suggest that relatively

high task and ego goal orientations may be the most adaptive

goal proW le in rugby. Future research should aim to establish

whether similar goal orientation proW les can be identiW ed in

other samples of rugby players (e.g. female players, elite vs

non-elite players, senior vs junior grades) and other football

codes (e.g. Rugby League, soccer, Australian Rules).

Rugby Union and professionalism : The eV ect of

extrinsic rewards on players’ intrinsic motivation

K. Hodge and K. Wilson

School of Physical Education, University of Otago, Dunedin, New Zealand

We examined the eV ect that extrinsic rewards have had on the

intrinsic motivation of a group of professional `Super 12’

rugby players (i.e. the many rewards associated with pro-

fessional rugby). The study had three speciW c aims: (a) to


compare the levels of intrinsic motivation between profes-

sional (n = 23) and club players (n = 96) in a New Zealand

province, (b) to compare goal orientations and perceived

competence in professional and club players, and (c) to

examine the relationships between these variables and

intrinsic motivation (measured with the Sport Motivation

Scale: Pelletier et al., 1995: Journal of Sport and Exercise

Psychology, 17, 35 ± 53). Multivariate analysis of variance

revealed no signiW cant diV erences in intrinsic motivation

between professional and club players; however, follow-up

univariate F-tests revealed that professional players had higher

`overall intrinsic motivation’ and higher levels of `intrinsic

motivation to experience stimulation’ than club players. These

W ndings suggest that the professional players perceived the

extrinsic rewards as primarily informational rather than con-

trolling; hence the maintenance of intrinsic motivation (Deci

and Ryan, 1985: Intr insic M otivation and Self-determination in

Human B ehavior. New York: Plenum Press). In addition, task

goal orientation was low to moderately correlated with

intrinsic motivation and was a good predictor of levels of

overall intrinsic motivation (Duda et al., 1995: International

Journal of Sport Psychology, 26, 40 ± 63). There are practical

implications of these W ndings for the continued development

of professional rugby players.

Bilateral m otor perform ance eV ects from training the

non-dominant foot in com petitive soccer players

J. HoV1 and E. Haaland2

1Norwegian University of Science and Technology, Department of Sport

Sciences, Trondheim and 2Stadion Medical Practice, B ergen, Norway

Soccer players are encouraged to learn to dribble, shoot or

kick the ball with either foot to improve performance. Whether

handedness, or rather `footedness’ , is a function of nature

or nurture is still debatable, as is the functional question of

whether the dominant or the non-dominant side should be

trained W rst, to achieve optimal performance. The aim of

this study was to evaluate bilateral motor performance eV ects

from training the non-dominant foot in competitive soccer

players.

Forty-seven performance-matched soccer players aged 15±

20 years were divided at random into an experimental group

(n = 24) and a control group (n = 23). The players all belonged

to the same club and were thus exposed to the same training

regimen.

Both groups were tested on the dominant and non-

dominant side using a standardized non-football-speciW c foot-

and hand-tapping test, and soccer-speciW c tests: a dribbling

pattern, a goal-scoring test and a one-touch direct pass. The

training group had to perform all parts of training except full

play using their non-dominant foot. Total time spent training

in the 8 weeks of training for both groups was 2768 min, of

which the training group used the non-dominant foot for 705

min. The control group showed no change in test performance

from pre- to post-test. The training group improved signiW -

cantly (P < 0.05; t-test for paired samples) from pre- to post-

test in all tests using their non-dominant side. Performance on

the football-speciW c tests improved in the training group using

the non-dominant side by 6.1% more than in the control

group. Interestingly, the training group also improved signiW -

cantly on all tests using their dominant side, by 6.2%.

The results could be explained based on improved general-

ized motor programs, or from a dynamical systems approach,

where what is trained is to handle all information available and

let the body self-organize motor performance.

Playing like cham pions: Notation analysis of European

and South Am erican international football

D. Lee,1 T. Shelton,1 T. Reilly1 and E. Rienzi2

1Research Institute for Sport and Exercise Sciences, Liverpool John Moores

University, Liverpool, UK and 2Unisport, Montevideo, Uruguay

Patterns of play that are successful in international tourna-

ments on one continent may not be transferable to other con-

tinents. Computer-based notational analysis techniques were

used to compare the achievements of successful teams in

international tournaments in Uruguay in the 1995 Copa

America and in Germany in the 1996 European Champion-

ship. Four matches were analysed from each tournament,

from the group stages through to the W nal. Germany achieved

an average of nine shots per game with 64% from three passes

or less. Uruguay averaged 12 shots per game with 79% from

three passes or less. Seventeen (47%) of Germany’ s shots were

from 18 yards or more, while 23 (43%) of Uruguay’ s were

from that distance. A high proportion of German shots (42%)

came from passing moves originating on the right-hand side of

the pitch. The highest proportion of Uruguayan shots came

from moves that started in the middle of the pitch (47%).

Passing quality was measured in relation to the number of

successful passes completed by each team. Germany per-

formed 307 ± 29 (mean ± s) passes per game, with a com-

pletion rate of 86%. Uruguay performed 230 ± 49 passes per

game, with a lower completion rate of 77%. Matthias Sammer

was Germany’ s most inXuential player (59 ± 17 passes per

game). The results indicate that Uruguay was more successful

than Germany in creating scoring opportunities by using

rapid progressions when turnovers of play occurred. However,

Germany was better at retaining possession of the ball through

superior passing quality.

A gam e perform ance analysis by age and sex am ong

Finnish national youth soccer players

P. Luhtanen,1 T. V„nttinen,1 M. H„yrinen1 and E.W. Brown2

1Research Institute for Olympic Sports, Jyv„skyl„, Finland and

2Institute

for the Study of Youth Sports, Michigan State University, East Lansing,

MI, USA

All actions in soccer vary in time, space, speed and direction of

movement. Thus, each individual action by a player can be

considered a random test of individual skills, physical abilities,

tactical understanding and team skills. The aim of this study

was to examine game performance and its relationships with

game understanding, physical abilities and technical skills

among Finnish national youth players.


Players (n = 106) from six First Division clubs served as par-

ticipants. Boys and girls formed two teams in each age group

(16 and 18 years) and they played with other players of their

own age and sex. OY cial Finnish Football Association rules

were applied to each match. All matches were recorded with

a JVC camcorder. The matches were analysed using SAGE

Game ManagerTM for Soccer software. The game performance

results were standardized for 90 min playing time. Test bat-

teries were used to measure technical skills (ball control,

passing and dribbling), physical abilities (time to sprint 30 m,

maximum vertical jump and time to complete a shuttle run)

and game understanding (oV ensive and defensive play) in

soccer. A linear stepwise regression analysis (criteria P = 0.05)

was applied to the successful action that occurred under

match conditions and to the variables tested. The dependent

variables were the percentage of successful manoeuvres in

receiving the ball (RE), passing the ball (PA), running with the

ball (RU), shooting (SH), tackling (TA), intercepting (IN) and

total average of all successful manoeuvres (TO) obtained

using the SAGE analysis system. The independent variables

were the individual results in the physical tests, skill tests and

game understanding tests.

In the boys, game understanding of defensive play was sig-

niW cant in explaining successful manoeuvres in all oV ensive

manoeuvres (RE + PA + RU + SH) in matches (F = 9.82, P =0.004, R

2 = 0.253), in receiving the ball (F = 9.82, P = 0.004,

R2 = 0.253) and in successful runs with the ball (F = 6.20,

P = 0.020, R2 = 0.205). In the girls, the passing test was sig-

niW cant in explaining successful runs with the ball during

matches (F = 10.21, P = 0.004, R2 = 0.290) and sprinting

speed was signiW cant in explaining tackling (F = 9.25, P =0.005, R

2 = 0.242). Among the groups of girls based on age,

the physical and skill tests in the main explained (F > 4.88,

P < 0.046, R2 > 0.273) successful manoeuvres in match con-

ditions. Among the groups of boys based on age, skill, physical

and game understanding signiW cantly (F > 4.97, P < 0.043,

R2 > 0.262) predicted successful actions in match conditions.

We conclude that the playing abilities (physical, skill and

game understanding) of boys in this age category were better

balanced than in girls.

A com parison of selected physical, skill and gam e

understanding abilities in Finnish youth soccer players

P. Luhtanen,1 T. V„nttinen,1 M. H„yrinen1 and E.W. Brown2

1Research Institute for Olympic Sports, Jyv„skyl„, Finland and

2Institute

for the Study of Youth Sports, Michigan State University, East Lansing,

MI, USA

The aim of this study was to examine and compare physical

abilities, technical skills and game understanding in Finnish

national youth players. Soccer players (n = 106) from six

First Division clubs served as participants representing two

teams in each age (16 and 18 years) and sex [boys (B) and

girls (G)] group. The numbers of participants by group

were as follows: B-16, n = 32; B-18, n = 28; G-16, n = 32; and

G-18, n = 24. The test batteries were as follows: physical tests ±

sprinting time for 30 m measured with photocells (± 0.01 s),

shuttle running time for four ´ 10 m measured using a video

timer (± 0.04 s), vertical jumping height measured with the

ERGOJUMP contact mat (Bosco et al., 1983: European

Journal of Applied Physiology, 50, 273 ± 282); skill tests ± ball con-

trol, dribbling and passing (Luhtanen, 1988: In Proceedings

of the 1988 Seoul Olympic ScientiW c Congress, Vol. II, pp. 1217±

1221); game understanding tests ± video segments of a soccer

match for which participants were evaluated, both oV ensively

(with and without ball) and defensively, on their ability to

orient themselves and understand space and time, play situa-

tions, and movements of the players and ball. For the video

segments, the participants had to decide quickly what they

would do in each situation and then justify their decision.

Analysis of variance was used to examine the main eV ects of

age and sex. Pearson’ s correlation coeY cients were calculated

between each of the test variables.

As expected for the physical tests, the boys performed

signiW cantly better in the 30 m sprint (F > 171.4, P = 0.000),

vertical jump (F > 67.39, P = 0.000) and shuttle run (F =66.13, P = 0.000). Similarly, the older participants performed

signiW cantly better in the 30 m sprint (F = 3.78, P = 0.056),

vertical jump (F = 3.56, P = 0.064) and shuttle run (F = 5.75,

P = 0.019). In the skill tests, signiW cant diV erences, favouring

the boys, were also found in ball control (F = 15.82, P =0.000), passing (F > 55.40, P = 0.000) and dribbling (F =41.55, P = 0.000). Age eV ects were signiW cant in passing

(F = 3.53, P = 0.065) and dribbling (F = 6.05, P = 0.017). In

game understanding, signiW cant diV erences, favouring the

boys, were only found in the understanding of defensive play

(F = 25.22, P = 0.000). The highest correlation coeY cients

among the physical test items and among the skill test items

were found in the girls: between vertical jump and sprinting

speed (r = 0.699, P = 0.000) and between dribbling and

passing test (r = 0.655, P = 0.000). In game understanding,

the highest correlation coeY cient also occurred in girls,

between the understanding tests of oV ensive play with and

without the ball (r = 0.393, P = 0.019). We conclude that

game understanding was the least discriminating variable in

assessing player abilities in soccer between boys and girls aged

16± 18 years.

Relative timing of EMG proW les for novice and elite

soccer players

M.D. McDonald

Queensland University of Technology, B risbane, Australia

Relative timing, a construct often used by motor control

theorists to account for skilled motion, is considered invariant

if the times allotted to the various events or phases of the

movement remain in constant proportion with respect to the

total movement time, regardless if the overall time varies.

The aim of this study was to determine if relative timing, as

evidenced from electromyographic (EMG) patterns, exists at

the neuromuscular level as opposed to the kinematic level

within the instep soccer place kick.

Fifteen non-soccer players (mean age 19.3 years) and 15

elite soccer players (age 25.6 years) performed 12 trials under

two diV erent kicking conditions (fast and slow). Kinematic

data were recorded by high-speed video simultaneously with


muscle activity. The EMG signals were recorded for the rectus

and biceps femoris, tibialis anterior and gastrocnemius of the

kicking leg. The signals were rectiW ed and enveloped as out-

lined in Winter (1983: Journal of M otor B ehaviour, 15, 302±

330). The EMG data were analysed with reference to phases

within the kicking motion identiW ed from the video. The

statistical test of Gentner (1987: Psychological Reviews, 94,

255 ± 276) was then applied to individual participants’ EMG

data to determine if relative timing was maintained despite

variations in the kicking leg kinematics.

The results indicated that not one muscle or phase of the

kicking movement sequence could W t into Gentner’ s notion of

relative timing. The results imply that the EMG activity time

spent in the various phases of the kicking motion are not kept

in proportion as the movement is scaled and modiW ed to meet

changing tasks demands. This W nding casts doubt upon claims

that relative timing is an invariant feature in movement tasks.

Inter-individual variability was high, even among the expert

players, indicating that there are many combinations of muscle

action that can produce kinematics which are consistent with

the goal of the task.

Can crowd reactions inX uence decisions in favour of

the hom e side?

A.M. Nevill, N. Balmer and A.M. Williams



Previous research has both conclusively identiW ed a home

advantage in team sports, and shown that oY cials make more

subjective decisions in favour of the home side (e.g. Nevill et

al., 1996: Journal of Sports Sciences, 14, 181 ± 186). The aim of

the present study was to determine whether knowledgeable

observers’ opinions of tackles/challenges in soccer can be

inXuenced by the noise of a partisan home crowd. Eleven

experienced observers (qualiW ed referees, coaches and semi-

professional footballers) viewed 52 tackles/challenges from a

televised football match, of which 26 were made by a home

player and 26 by an away player. Six of the participants

observed the videotape with no background noise, while the

remaining W ve observed the videotape in the presence of

background crowd noise. The percentage of fouls awarded by

the two groups of observers and the referee, for challenges by

the home and away players, are given in Table 1.

Analysis of the mean percentage of fouls awarded by the

observers (excluding the referee ’ s data) using analysis of

variance (ANOVA) identiW ed a signiW cant two-way interaction

between `noise group’ and `team representation’ (F1,9 = 8.2,

Table 1. Percentage (± s) of fouls awarded by the observers and the

referee, for challenges by the home and away players

Home Away

No noise (n = 6)

Crowd noise (n = 5)

Referee (n = 1)

57.6 (± 9.8)

50.0 (± 4.7)

50.0

48.3 (± 1.9)

56.9 (± 5.0)

65.4

P = 0.019). In recognizing the limitations of using traditional

ANOVA to compare binomial proportions, an arcsine trans-

formation was used to stabilize the variances. This yielded

similar values for the two-way interaction (F1,9 = 8.2, P =0.019), although the residuals were more acceptably normal

than the non-transformed analysis. The observers showed

a tendency to penalize the home players less, and the away

players more, when exposed to crowd noise. We suggest,

therefore, that noise might have a similar eV ect on oY cials’

decisions, and provide a possible explanation for the home

advantage phenomenon.

Visual reaction time and peripheral vision in

professional Rugby League players

D. O’ Connor and M. Crowe

James Cook University, Townsville, Australia

Quality performance in Rugby League relies on good visual

skills, such as quick reaction time and the ability to be aware

of the presence of both team-mates and opposition players

while following the play of the ball. The aim of this study was

to determine whether there were any diV erences in visual

reaction time (RT) and peripheral vision (PV) between dif-

ferent grades of professional Rugby League players, between

positions, between players of light or dark eye colour and

under fatigue. Sixty-three male players from a National Rugby

League (NRL) club (three grades of 21 players) were tested

using the Acuvision 1000. Both tests required the players to

respond to 60 random lights with central W xation for the

PV test. They were scored on time and number of correct

responses. Comparison of the three teams on both tests

showed that the W rst-grade players had a signiW cantly faster

response time on the PV test (P = 0.002) and scored a greater

number of hits on this test than the under-20 players

(P = 0.003). There were no diV erences between the three

grades on time or hits in the RT test. Players with dark eye

colour performed signiW cantly better than light-eyed players

on the PV test (time: P = 0.001; hits: P = 0.002) but not on

the RT test. The players’ position did not aV ect visual

performance. A maximal 60 s cycle test had no eV ect on scores

on the RT test or time to perform the PV test, but reduced

signiW cantly the number of correct hits in the PV test

(P = 0.023). These results suggest that peripheral vision may

be important in elite performance, is aV ected by fatigue and

should be included in training.

Group cohesion in English professional football:

A case study of youth trainees

A. Parker and B. Hemmings

University College Northampton, Northampton, UK

The study of group processes has constituted a central theme

within sport psychology, with group cohesion a popular

research-based construct. In recent years, English professional

football clubs have adopted a two-year ̀ apprenticeship’ system

that requires youth team coaches to place a heavy emphasis on


the development of cohesiveness between W rst- and second-

year trainees. Using data gathered within the context of

one prestigious club, the aim of this study was to investigate

group cohesion among youth (aged 16± 19 years) trainees.

Weinberg and Gould (1995: Foundations of Sport and Exercise

Psychology. Champaign, IL: Human Kinetics) have identiW ed

that, although questionnaires have typically been used to

measure group cohesion, they fail to demonstrate how

individuals within a group relate to each other, whether

cliques are forming, and if some individuals are socially iso-

lated. By adopting a more qualitative approach, sociometric

analysis was used to measure social cohesion, in an attempt to

consider aY liation and attraction among 20 youth trainee

footballers. The resulting sociogram showed evidence of

reciprocal and non-reciprocal relationships between trainees,

with a notable diV erentiation between W rst- and second-year

trainees, thereby suggesting clique formation, social isolation

and poor levels of social cohesion. Although it has been shown

that task rather than social cohesion has a stronger relationship

with performance (Widmeyer et al., 1985: The M easurement of

Cohesion in Sports Teams: The Group Environment Questionnaire.

London, ON: Sports Dynamics), it has been argued that

close-knit teams seem to enjoy being together on and oV

the athletic W eld (Partington and Shangi, 1992: International

Journal of Sport Psychology, 23, 28 ± 47). This analysis suggests

the need for interventions outside of practice.

Hom e advantage: A case study of Ipswich Town Football

Club during the 1996± 97 season

Y. Sasaki,1 A. Nevill2 and T. Reilly2

1Sanfrecce Hiroshima FC, Japan and

2Research Institute for Sport and

Exercise Sciences, Liverpool John Moores University, Liverpool, UK

The phenomenon of home advantage in English and Scottish

League soccer has been reported by Nevill et al. (1996: Journal

of Sports Sciences, 14, 181 ± 186). Observations have been made

for the leagues as a whole rather than single clubs and have

not been acknowledged by performers. The aims of this study

were to assess the degree of home advantage using a total of

26 Ipswich Town league matches, 13 games being paired/

matched home and away, and to explore the players’ percep-

tions of home advantage using a short questionnaire. All

matches and player responses were recorded during the 1996±

97 season. The 26 Ipswich Town league matches, recorded

on videotape, were analysed using a hand notation system.

Information concerning the players’ critical psychological

states and thoughts on home advantage were assessed using

a 30-item questionnaire. The data were analysed using a

one-sample Wilcoxon non-parametric test of signiW cance.

The players completed the questionnaire twice. In the home

version, the players were asked to indicate which factors bene-

W ted them `when playing at HOME’ , using a 5-point scale

(1 = never to 5 = always). In the away version of the question-

naire, the players were asked to indicate, using the above scale,

which factors beneW ted them `when playing AWAY from

home’ .

Home advantage was observed in the number of games won

(7 wins, 4 draws and 2 losses at home, compared with 4 wins, 4

draws and 5 losses away from home). SigniW cant diV erences in

the following primary levels of performance were found to

favour the home team: goal attempts, shots on target, shots

blocked, shots wide, successful crosses and goal-kicks (P <

0.05). The players responded more positively when playing at

home (compared with playing away) to the following factors:

facility familiarity, crowd’ s expectation, crowd’ s judgement,

hostile reaction of the crowd, frustration and game domina-

tion (P < 0.05).

The results suggest that the observed home advantage,

clearly present based on the performance outcomes, might at

least be partially explained by the players’ greater expectation

to win more at home than away ± that is, `the self-fulW lling

prophesy’ .

Relationship between the assessm ent of individual

soccer coaches on players’ capabilities, and between

assessm ent and test results

D. Tumilty, L. Burke and D. Martin

Australian Institute of Sport, Canberra, ACT, Australia

The validity of laboratory and W eld tests for team sports in

terms of how well such tests assess ability in the game is a

diY cult problem for researchers. One method of determining

validity involves comparison of the ranking of players on dif-

ferent qualities according to the views of experienced coaches

with the ranking obtained from tests purporting to measure

these qualities. This method can only be considered useful if

there is a good correlation between the opinions of coaches

interrogated. The aims of the present study were to determine

the correlation between the opinions of two experienced

soccer coaches working with the same team on six game-

related qualities, and between the opinions and a variety of

game-related laboratory and W eld tests.

The participants were nine male players of an elite youth

soccer squad (mean age 17.0 years, mean VÇ O 2max 58.1

ml ´ kg - 1 ´min - 1). As part of a larger study, the participants per-

formed two fatiguing soccer-related 26 min treadmill runs.

Before the W rst and after the second run, and between the two,

the participants performed several tests on an Acuvision board

for speed of reaction and decision-making ability, and also

W eld tests for speed, and for dribbling and shooting ability. The

best score on each test was used in the present investigation.

The VÇ O 2max was assessed from a progressive treadmill test.

Rank-order correlation coeY cients between coaches’ opinions

were signiW cant (P < 0.05) for the qualities of ability to read

play and game work rate, but not for quick reaction to the

unexpected, ball control, passing and shooting accuracy, and

on-pitch speed. Correlations were non-signiW cant between

individual coach’ s opinions and all rank-ordered test results,

except between the opinion of one coach on game work rate

and tests of dribbling and VÇ O 2max.

The results suggest that the validity of laboratory and W eld

tests for soccer qualities need to be based on factors other than

coaches’ opinions of these qualities. The limited realism of

even game-related laboratory and W eld tests may also be a

factor.


Factors aV ecting decision-making of soccer referees

R. Verheijen, R. Oudejans, P.J. Beek and F.C. Bakker

Faculty of Human Movement Sciences, Free University, Amsterdam,

The Netherlands

The ability to perceive events in complex sport settings both

quickly and accurately is an essential element of skilled

performance. A game of soccer is such a complex setting,

as decisions are made by 22 players and three oY cials (one

referee and two assistant referees). However, in research to

date on perception and decision-making in soccer, only

players have been studied. We studied three elite referees while

in charge of four elite youth matches of 60 min duration each.

One referee was in charge of each match for 20 min. The

referees’ performance was assessed by three oY cial observers

from the Royal Netherlands Football Association (KNVB).

The speed of movement of the referees and their proximity to

play were also determined.

In 4 h of play, the three referees made 61 incorrect

decisions. They moved signiW cantly more slowly (t = - 7.76,

P < 0.001) when making correct decisions (mean ± s: 2.00 ±1.04 m ´ s - 1) than when making incorrect decisions (4.17 ±1.98 m ´s - 1). The distance between the referee and a game-

play was signiW cantly greater (t = - 3.89, P < 0.001) for correct

decisions (17.74 ± 7.58 m) than for incorrect decisions

(12.68 ± 5.68 m). These results suggest that soccer referees

should take decisions when walking, rather than standing still

or running, as often as possible, and that they should keep a

distance of between 20 and 25 m from play to be able to judge

a game-play accurately.

EV ects of practice and knowledge of perform ance on

the kinematics of ball kicking

A.M. Williams, P. Alty and A. Lees



Changes in movement kinematics were examined during

the acquisition of a soccer kicking action with and without

knowledge of performance. Previous research has used out-

come rather than process measures to assess skill learning, and

few studies have manipulated knowledge of performance as

a learning variable (Anderson and Sidaway, 1994: Research

Quarterly for Exercise and Sport, 65, 93± 99).

Eight skilled and 16 novice soccer players were required

to kick a stationary ball towards a target area using the

right instep. Novice participants were randomly assigned to

either `practice-only’ or `practice plus augmented feedback’

(knowledge of performance) groups, whereas the skilled

participants acted as controls. Although both novice groups

received the same amount of physical practice, 240 trials

over 4 weeks, the knowledge of performance group received

verbal prescriptive feedback every third trial. Statements

about knowledge of performance were provided by experi-

enced soccer coaches based on the criteria established for

successful performance (e.g. Magill and Schoenfelder-Zohdi,

1996: International Journal of Sport Psychology, 27, 7± 22). Per-

formance before and after practice was videotaped (50 Hz)

from a side-on perspective for subsequent kinematic analysis.

Analysis of variance indicated that novice participants

increased foot linear velocity (11.22 vs 12.02 m ´ s - 1), ball

velocity (13.15 vs 14.91 m ´ s - 1) and range of motion at the

lower leg (1.39 vs 1.52 rad) and foot (1.60 vs 1.82 rad) from

pre- to post-test (P < 0.05). However, the knowledge of

performance group recorded a larger increase in ball velocity

(2.4 vs 1.11 m ´ s - 1) and lower leg range of motion (0.06 vs

0.20 rad) compared with the `practice-only’ participants

(P < 0.05). Qualitative analysis using angle-to-angle diagrams

revealed that both novice groups adopted coordination

patterns that were more comparable with those displayed by

the skilled participants as a result of practice. Our W ndings

highlight the role of knowledge of performance in skill acquisi-

tion and emphasize the importance of using process as well as

outcome measures to assess skill learning.

An analysis of the playing patterns of the Japan national

soccer team in the 1998 World Cup

K. Yamanaka,1 T. Nishikawa,1 T. Yamanaka1 and

M.D. Hughes2

1Institute of Health and Sport Sciences, University of Tsukuba, Japan

and 2Centre for Notational Analysis, CardiV Institute, CardiV, UK

In November 1997, when coming third in the Asian Cup

qualifying matches in Malaysia, Japan qualiW ed for the 1998

FIFA World Cup tournament in France. This was the W rst

time Japan had qualiW ed for such a tournament. Japan lost

all three games in Group H, meaning that the team did

not advance to the knock-out stages. However, that Japan

qualiW ed at all is a result of the formation of the `J-League’

and the inXux of European and South American players and

coaches. In this study, we examined the skills and tactics dis-

played by the Japan national soccer team at the 1998 World

Cup W nals.

We performed a computerized notational analysis of games

in the 1998 World Cup, with a particular emphasis on Japan.

Three games were selected for study to analyse the playing

patterns of the respective teams: Japan vs Argentina (score

0± 1), Japan vs Croatia (score 0± 1) and Japan vs Jamaica (score

1± 2). We used software developed by Hughes et al. (1988:

In Science and Football, edited by T. Reilly, A. Lees, K. Davids

and W. Murphy, pp. 363 ± 367. London: E & FN Spon) to

input the data. Performance data were entered while replay-

ing the videotapes of the games a number of times. Thirty-

two diV erent actions were categorized by time, place,

player and action. Based on a 90 min game (excluding injury

time), and by dividing the pitch horizontally and vertically

into 18 quadrants, the frequency of each action in each

quadrant was recorded. For statistical processing, we used the

x2 test.

Japan passed the ball more often than Croatia (P < 0.01)

but less often than Argentina (P < 0.01). Japan dribbled the

ball less often than either Argentina (P < 0.01) or Croatia

(P < 0.05). Japan attempted more shots on goal than Jamaica


(P < 0.05) but fewer than Argentina (P < 0.01). Japan made

more crosses than Jamaica (P < 0.01). Japan cleared the ball

from defence more frequently than Argentina (P < 0.01) but

less frequently than Jamaica (P < 0.01). In line with the results

of Yamanaka et al. (1993: Ibaraki Journal of Health and Sport

Sciences, 9, 17 ± 27), in the World Cup W nals Japan dribbled

the ball much less frequently than its opponents (Japan vs

Argentina 49 vs 95, Japan vs Croatia 58 vs 85, Japan vs Jamaica

54 vs 62).

The frequencies of crosses, passes and defensive clearances

by Croatia and Jamaica characterize a defence-oriented

pattern of play. The frequencies of cross-W eld passes and

shots on goal are closely related to scoring. Based on these

inferences, the performance of Japan in the three games was

unstable, often as a result of poor skills. Teams that dribbled

the ball more frequently relied on individual skills in their

attacking play. It would appear that Japan played more

organized football, preferring to pass the ball rather than rely

on individual attacking skills.

Japan’ s priority was in controlling the ball. Japan made more

passes in the midW eld area of the opponents (P < 0.05) and

in attack (P < 0.01) than Croatia or Jamaica but not Argentina

(P < 0.05 and P < 0.01 respectively). Japan made fewer passes

in defence than Jamaica (P < 0.01). The frequency of passing

by Japan in its own half and its opponent’ s half in the

Argentina, Croatia and Jamaica matches was as follows: own

half 174 (59.2%), 120 (40.8%) and 206 (54.4%); opponent’ s

half 173 (45.6%), 215 (49.4%) and 220 (50.6%). In contrast,

the frequency of passing by Argentina, Croatia and Jamaica in

their own half and their opponent’ s half was 220 (48.8%) and

210 (51.2%), 204 (69.9%) and 88 (30.1%), and 284 (71.9%)

and 111 (28.1%), respectively.

In conclusion, it is important for Japanese footballers to

develop their attacking skills by using `negative space’ eV ec-

tively and by making more backward passes from midW eld to

plan attacks.

PART III: BIOM ECHANICS AND M EDICINE

The traction of football boots

E.B. Barry1 and P.D. Milburn2

1Department of Human B iology and Movement Science, Royal Melbourne

Institute of Technology, Melbourne, Australia and 2University of Otago,

Dunedin, New Zealand

The aims of this study were to design a traction test device, to

measure traction between football boots and natural surfaces,

and to explain how traction develops. The traction device

was designed and constructed to move a football boot at a

given slide rate at W xed slide directions. A range of vertical

loads (0± 80 kg) could be applied to a boot through a free

sliding vertical shaft, although for most tests the same load was

used. Four makes of boots held in four slide directions were

tested on three surfaces: Sports 40 sand (sand), StrathAyr

Netlon turf (Netlon), StrathAyr natural river loam turf

(loam). Both turfs were sown with a cool species of grass and

the moisture contents of all surfaces ranged between air

dry (1.7%) and 28.7%. Each surface was W xed to a Kistler

force plate. Data acquisition software written for an IBM PC

computer controlled the force plate and its ampliW er, the

traction device and a vertical displacement transducer. Non-

linear regression analysis was used to W t all data on an

exponential model. Their coeY cients of determination ranged

between 0.6039 and 0.9983. The peak traction force deter-

mined from the model ranged between 123 and 1115 N. In

sand, the traction force increased from approximately 150

to 200 N with an increase in moisture content (1.7 ± 19%)

depending on the direction of slide. For Netlon it ranged

between approximately 300 and 700 N, apparently indepen-

dent of the increase in moisture content (16.9 ± 28.7%).

Finally, for loam, the range was approximately 300 to 1000 N,

also apparently independent of moisture content (21.5±

28.9%). In summary, both turfs resulted in higher traction

values than the sand, and the river loam developed the greatest

traction force, which could increase the likelihood of injury to

players on this surface. Finally, traction is aV ected by the type

of surface, moisture content, slide direction, and the shape,

number and location of the studs.

Biom echanical analysis of the instep-kick in soccer

S. Basumatary,1 R.K. Begg1 and N.T. Diamond2

1Centre for Rehabilitation, Exercise and Sport Science and

2School of

Communications and Informatics, Victoria University of Technology,

Melbourne, Australia

There has been limited research on the eV ects of approach

angle on three-dimensional (3-D) kinematics of the instep-

kick in soccer. The aim of this study was to assess the eV ect of

variations in approach angle on distance covered by the ball,

accuracy of the kick and 3-D lower limb kinematics. The kick-

ing motions of 20 male soccer players were analysed using a

PEAK 3-D motion analysis system. Two synchronized 50 Hz

video cameras placed 90° apart recorded the instep-kick

for seven approach angles (0° to 90° at 15° intervals). The

3-D coordinates of 21 anatomical locations (upper and lower

limb body segments and joint centres) and the ball centre

were digitized manually using the PEAK system’ s software.

Approach angle showed signiW cant eV ects on both distance

covered (P < 0.0001) and accuracy (P < 0.0001). The maxi-

mum distance covered (xÅ = 39.0 m) and the best accuracy

(xÅ = 0.92 m) were for an approach angle of 45°. Regression

analysis revealed that approach angle contributed about 75%

of the residual variance after adjusting for individual eV ects,

suggesting that approach angle is an important factor in the

determination of a successful instep-kick. Stepwise regression

analysis suggested the toe linear velocity (P < 0.027), as well as

hip (P < 0.002) and knee (P < 0.006) joint angular velocities,

at ball contact were signiW cant contributors to distance

covered (R2 = 0.90). These results suggest that approach angle

and some of the lower limb kinematics at ball contact play an

important role in the execution of the instep-kick. They also

suggest that the instep-kick involves complex movement of

the whole body, especially the lower extremity, and requires a

3-D representation for its complete analysis.


Risk factors for further injury in a cohort of rugby

players

Y.N. Bird, D.J. Chalmers, S. Williams, B.D. Wilson and

D.F. Gerrard


New Zealand

That previous injury is an injury risk factor in sport has been

shown in a number of epidemiological studies. Several con-

tributing factors have been proposed, including lack of healing

time, site of injury, type of injury and psychological factors.

The aim of this study was to identify potentially modiW able

risk factors for further injury in Rugby Union.

The Rugby Injury and Performance Project (RIPP) was

designed to identify risk and protective factors for rugby-

related injury using a prospective cohort design. Data on

life events and injuries sustained by 350 club players were

collected via weekly telephone interviews throughout the 1993

playing season. Further injury within the cohort was investi-

gated for 190 male players who received one rugby injury

in a game during the season. Univariate analyses were per-

formed, including Kaplan-Meier survival curves. A multi-

variate analysis was then performed using Cox’ s proportional

hazards model. The outcome variable was `games to second

injury’ .

In total, 102 players (53%) received two injuries in the

season; 88 did not receive a second injury. Players with a

dislocation had fewer games to second injury (RR = 11.9,

P = 0.004). Severity was measured by time away from play.

Players who returned to playing within 1 week were at a higher

risk of further injury compared with those who did not play for

2± 3 weeks (RR = 0.67, P = 0.098) and those who did not play

for more than 3 weeks (RR = 0.38, P = 0.001). Body mass

index and W tness factors did not contribute to risk of further

injury. The issue of severity has not been included in many

reports of further injury or recurrent injury. The impact of

minor injury on performance and future injury may not be

recognized at this level. Injuries may be minimized by coaches

and players so they may take the W eld in the next game with

little regard for future injury and performance.

An injury prevention strategy for Rugby Union

H.R. Broughton, F. Phillips and K. McKinney

Ponsonby District Rugby Football Club, Western Springs Stadium,

Auckland, New Zealand

The aim of this study was to gather data so that programmes

can be developed to prevent injuries. Two hundred players

from the Ponsonby District Rugby Football Club were

surveyed for injuries in the 1998 season. Data collected

included: player number and position, injury site and type,

which quarter the injury occurred in, how the injury

happened, what protective equipment was worn and what

treatment was given. An injury was deW ned as a player leaving

the W eld to receive medical treatment. There was a total of

227 injuries reported for 133 events. Strains, bruising and

sprains represented 77.5% of recorded injuries; running

injuries represented 47 (28%) of total injuries. In the tackle,

there were 112 (48.7%) injuries, including 68 (29.6%)

causing injuries to the head, face, shoulder and legs and 44

(19.1%) causing injuries to the arms and shoulder. Wing

three-quarters, props, Xankers and half-backs, in that order,

experienced most injuries. Strapping data from the senior

One and Premier teams demonstrated that the wrist (n = 194),

ankle (n = 84) and thumb (n = 53) were the joints most

commonly strapped. The results suggest that conditioning

protocols for minimizing joint injuries, and coaching

techniques for running and tackling, be researched to assess

the eV ect of an injury prevention programme.

EV ects of training and sex on injury rate and type in

collegiate soccer players in the United States

K.M. Bruntzel and N. Messenger

University of Leeds, Leeds, UK

The aim of this study was to determine whether sex or training

intensity had an eV ect on lower-extremity injury rate and type

in collegiate soccer athletes in the USA. Using a question-

naire, retrospective injury information for a `fall’ season was

obtained for 877 male and 1027 female collegiate soccer

players. An acute injury rate of 66.9% and a chronic/overuse

injury rate of 24.6% were reported by the athletes as a whole.

A chi-square analysis showed no statistical diV erences between

the sexes (P < 0.05), although some diV erences between the

sexes were evident in the types of overuse injuries sustained.

Playing surface type had no eV ect on injury rate. Teams

practising 6± 9 h per week sustained the lowest percentage

of injuries (66.3%), while those practising 9± 12 h per week

reported the highest percentage of injuries (103.1%).

Although the highest levels of chronic/overuse injuries

occurred in the groups that practised the least per week

(6± 9 h) and those that practised the most ( > 15 h), the low-

est injury rate (65.7%) was reported by teams that played

three scrimmages (moderate intensity) during their weekly

practices. The highest injury rate (146.6%) was reported by

teams that played ³ 6 scrimmages (highest intensity) per week.

Finally, a 25% higher rate of injury was reported by teams that

played three or more games per week. The results indicate that

injury rates in soccer were not related to the sex of the players,

although some diV erences between the sexes were observed in

the types of overuse injuries they incurred. They do suggest,

however, that practice time and intensity, as well as game

scheduling, can adversely aV ect injury rates.

Method for graphical analysis of the soccer kick using

spherical coordinates of the lower lim bs

S.A. Cunha, R.M.L. Barros, E.C. Lima and R. Brenzikofer

Paulista State University, Rio Claro, B razil

Analysis of the behaviour of the lower limb during kicks is an

important procedure to detect soccer players’ characteristics.

Graphical analysis of kinematic data helps to identify motor

patterns and the skill of individual athletes. The aim of this


study was to analyse the lower limb using spherical coordin-

ates to represent motor patterns when performing a soccer

kick. The player analysed kicked a stationary ball 12 times in

front of the kinematics analysis system. The ball was placed a

distance of 11 m from the goal, and the task was to hit the ball

into the upper and lower extremes of the goal. We measured

the points that represent the hip, knee and ankle joints of the

dominant leg and performed a transformation from cartesian

to spherical coordinates and smoothed the discrete data using

a loess function. The spherical coordinates in motor pattern

analysis allow independence of the reference system because

of the unitary radius sphere centred on the hip joint (thigh)

and the knee joint (shank). Using the latitude and longitude

variables for each segment, we made a stereographic pro-

jection; using the graphs of longitude by latitude, we veriW ed

that the individual investigated did not show much variability

in his kicks, showing a skilled pattern for this movement.

Comparison of football code injuries presenting to

sports m edicine clinics

B. Gabbe and C. Finch

School of Human Movement, Deakin University, Melbourne, Australia

Most data on football injuries in Australia come from hospital

emergency departments, hospital admissions, coroner’ s

records and injury surveillance in elite competitions. Multi-

disciplinary sports medicine clinics treat a large range and

number of sports injuries, yet there is very little information

describing the type, nature and causes of injuries presenting

to such clinics. The Sports Medicine Injury Surveillance

(SMIS) project was undertaken in W ve metropolitan

Melbourne sports medicine clinics over 12 months to pro-

vide a comprehensive epidemiological description of all new

sporting and recreational injuries presenting to these clinics.

Demographics, sports participation, cause of injury, nature of

injury, severity of injury, intent of injury and diagnosis were

examples of the data collected.

Of the 6479 injury cases recorded, 1868 (29%) occurred

during Australian Rules football, 223 (3%) were due to

soccer and 99 (2%) were due to Rugby Union. Rugby League

contributed just three cases of injury to the database and,

therefore, was not included in this comparison. The partici-

pants were predominantly male, ranging from 92% in soccer

to 99% in Australian Rules football. SigniW cant diV erences

in the proW le of players were found between the codes in

standard of competition played (P < 0.001), protective

equipment used (P < 0.05) and the age of participants (P <

0.05). Soccer demonstrated a higher proportion of social

participants, while a higher proportion of Rugby Union parti-

cipants were wearing protective equipment at the time of

injury. The proportion of injuries deemed intentional was

highest in Rugby Union. Collision and contact injuries were

more common in Australian Rules football and Rugby

Union, while overuse and twisting/rotation injuries were more

common in soccer. Contusions and fractures were more

common in Rugby Union and Australian Rules football. There

was no signiW cant diV erence between the codes with respect

to the expected amount of treatment needed for the injuries.

In summary, this study aids understanding of the epi-

demiology of injuries presenting to sports medicine clinics.

SigniW cant diV erences in the injury patterns were found

between the football codes. This W nding has implications for

future injury prevention research.

Risk assessm ent of ham string injury in Rugby Union

place kicking

P. Graham-Smith and A. Lees



An increased risk of muscle injury is thought to be inXuenced

by two main factors: a strength imbalance between agonist

and antagonist muscle groups, and poor Xexibility of the

antagonist muscles. The aims of this study were to provide

a method for assessing the risk of injury to the hamstrings

muscles during sport-speciW c activities (using muscle length

and isokinetic assessment) and to apply this to the place kick

in Rugby Union.

Eight male university place kickers (mean ± s: age 22 ± 2.6

years, height 181 ± 9 cm, body mass 82.6 ± 10.0 kg) were

recorded on video performing a maximum assisted hamstring

stretch and a maximal place kick. Following digitization, the

length of the biceps femoris muscle was calculated from hip

and knee joint angles (Visser et al., 1990: European Journal of

Applied Physiology, 61, 453± 460) to assess static and dynamic

Xexibility. A mean change in length of 34.3 ± 6.1% of segment

length was found in the static stretch and this increased to

45.2 ± 5.3% during a maximal place kick. The maximum

length was found to occur at the end of the follow-through

phase where the hip was Xexed (119 ± 12°) and the knee was

slightly Xexed (22 ± 11°). An isokinetic dynamometer (LIDO,

Loredan, Davis, CA) was used to measure concentric strength

of the quadriceps (Q) and hamstring (H) muscle groups at

test velocities of 1.05, 2.09 and 5.23 rad ´ s - 1, and eccentric

strength of the quadriceps and hamstring at 2.09 rad ´ s - 1.

Reciprocal muscle group ratios were calculated from the peak

torque values using the traditional concentric H/concentric

Q ratio and the `dynamic control ratio’ (DCR = eccentric H/

concentric Q). Concentric H/Q ratios were found to increase

with the speed of movement, registering values of 0.61 ± 0.07,

0.69 ± 0.07 and 0.86 ± 0.09 at angular velocities of 1.05,

2.09 and 5.23 rad ´ s - 1, respectively. The DCR was 0.75 ± 0.08,

which was less than an ideal ratio of 1.0 (i.e. the hamstring can

resist as much force as the quadriceps can produce).

The use of muscle length data was found to provide a link

between static Xexibility assessment and dynamic perfor-

mance, and also to determine whether eccentric hamstring

strength is more relevant than concentric in the assessment of

hamstring weakness. A reversal in the calculation procedure

indicated that place kickers require a hip range of motion of

118° to perform the action safely, some 25° further than that

exhibited (93°) in the maximal assisted stretch. This indicates

that advanced stretching techniques may be beneW cial to

players as part of their warm-up routine. As the biceps

femoris was observed to lengthen throughout the follow-

through phase, this suggests that the use of the DCR is more


appropriate for the assessment of hamstring weakness. We con-

clude that a DCR of 0.75 is suY cient for Rugby Union place

kickers when testing at an angular velocity of 2.09 rad ´s - 1.

Images of the process of Osgood-Schlatter’s disease

A. Hirano, T. Yukubayashi, N. Hirose, K. Ishiguri, T. Ishii,

S. Miyakawa and N. Ochiai

University of Tsukuba, Ibaraki, Japan

Osgood-Schlatter’ s disease (OSD) aV ects improvement in

athletic skill and sometimes forces young athletes to drop

out of competition. The aim of this study was to identify the

cause of OSD and outline recommendations to prevent its

occurrence and advancement. The tibial tuberosities of 107

young soccer players belonging to the junior category of a

professional soccer team were investigated continuously.

Thirty-seven cases in 26 male athletes (average age 13.7 years)

of clinically diagnosed OSD were examined by magnetic

resonance imaging. Ten cases were classiW ed as primary, W ve

cases as progressive and ten cases as terminal. Two cases were

classiW ed as being in the healing stage. Of 10 cases that were

classiW ed in more than two stages, eight were followed from

the asymptomatic or primary stage. The primary process of

OSD is that the tear appeared in the secondary ossiW cation

centre, widening to a shell-like shape (progressive stage). The

separate fragment progressed to unite in four cases (healing

stage) and failed to unite in one case (terminal stage). In the

terminal stage, patellar tendon enlargement and high signal

intensity are seen at the tendon insertion site. The ossicles

were enveloped in multiplied cartilaginous tissue. These

abnormalities made the healing process longer. A rest before

the terminal stage is needed for healing of the OSD without

sequelae.

Pubic stress tests and rehabilitation of osteitis pubis

A. Hogan and G. Lovell

University of South Australia, Adelaide, Australia

Sports medicine practitioners recognize that osteitis pubis is

a condition responsible for groin pain in footballers; Fricker

(1997: Sports M edicine and Arthroscopy Review , 5, 305± 312)

reported an average recovery time of 9.6 months. Retro-

spective review of 63 footballers with chronic groin pain

participating in Australian Rules football, Rugby Union,

Rugby League and soccer has provided some insight into

the diY culties faced by the clinician planning (staging) a

rehabilitation programme. There are few clinical signs to

indicate the correct time to commence running without risk

of exacerbation. The movement of the pubic symphysis has

been demonstrated in several planes; however, in his recent

review of osteitis pubis and pubic instability, Fricker (1997)

found clinical assessment of movement was limited to

radiographic evidence of movement in the vertical plane. To

overcome this problem, a series of pubic stress tests was

developed after retrospective analysis of 17 footballers. These

tests assess the pain response of the pubic symphysis to stress

in the sagittal, transverse and coronal planes (Hogan and

Lovell, 1998: Communication to the SM A (SA B ranch)

Annual Conference). These stress tests were found to be the

most reliable indicator of the appropriate time to commence

running (r = 0.92, P < 0.05) and lateral running (r = 0.87,

P < 0.05), while decreased tenderness to palpation (r = 0.56,

P < 0.05) was found to be the least reliable indicator in the

subsequent 46 footballers. The successful management of

osteitis pubis and pubic instability is not completely under-

stood, although the preliminary evidence from the clinical

observation of footballers suggests that these pubic symphysis

stress tests are a sensitive determinant of the correct staging of

rehabilitation. In the equivalent of the interval between playing

seasons (4± 5 months), the compliant footballer can: (1) regain

normal function of the muscles which attach to the pubic

symphysis; and (2) decrease the adverse stresses placed on

the pubic symphysis by abnormal hip and pelvic joint motion

and/or muscles which attach to the pelvis, and return to their

pre-injury level of football participation.

Three-dimensional kinematic analysis of the instep

kick under speed and accuracy conditions

A. Lees and L. Nolan



The instep kick in soccer has been the subject of numerous

2-D analyses. However, kicking has substantial 3-D character-

istics to its motion and these have not been fully explored by

the very few 3-D studies in the literature. Of particular interest

is the twisting motion of the hips and shoulders during the

kick and how these might contribute to performance. The

aims of this study were to deW ne these characteristics in pro-

fessional soccer players and to identify changes in them which

occur as the kick is performed with the requirements of

(a) speed and (b) accuracy.

Two professional soccer players were asked to take ten

instep kicks each with a stationary ball placed at a distance

from the goal mouth which would simulate a penalty kick.

They were required to hit a target in the top right corner of the

goal mouth. The requirement of the W rst W ve kicks was to hit

the target with an emphasis on speed of kick. The requirement

of the second W ve was to ensure accuracy of placement. Each

kick was W lmed at 100 Hz by two cameras and the 3-D

coordinates of body landmarks were reconstructed. From

these a variety of linear and angular displacement and velocity

measures were computed.

The mean speed of the `fast’ kick was 26.6 and 24.3 m ´ s - 1,

and for the `placed’ kick 20.4 and 18.1 m ´ s - 1, for the two

players respectively, verifying that the kicks were typical of

match-play. The shoulders rotated with respect to the hips.

The shoulders lagged behind the hips during the wind up

leading to a hip± shoulder separation angle. The range of

motion from maximum withdrawal of the pelvis to impact was

22° for both players for the `accuracy’ kick, and 34° and 30°respectively for the `fast’ kick, which diV ered signiW cantly

(P < 0.1). At impact, the hips and shoulders eV ectively were

in line, with the hip± shoulder separation angle close to zero.


The equivalent values for hip± shoulder inclination range of

motion were 2° and 3° for the `accuracy’ kick and 9° and 11°for the `fast’ kick.

The results suggest that trunk rotations are an important

component of the kicking skill and increase as performance

demands increase. This information has implications for skill

training and physical conditioning.

Validation of an instrum ent for data collection in

Rugby Union

A. McManus

Curtin University of Technology, Perth, Australia

Australia has over one million sporting injuries annually,

costing almost A$1 billion. Injury rates are relatively high in

the rugby codes in comparison to other sports; however,

a meta-analysis on rugby injuries over the previous 20 years

concluded no study met all the desirable criteria necessary to

ascertain the extent and nature of injury. This research

provides the basis from which injury rates can be collected

from a validated injury report form in Rugby Union. The

Injury Report Form was designed after considering the

W ndings of published research. It was then modiW ed using the

Delphi technique to achieve face and content validity. A series

of injuries were recorded on videotape and a `gold standard’

for each injury was devised by an expert panel using the Injury

Report Form. Intra-rater reliability was achieved by ten

independent triallists viewing the videotape on three separate

occasions. Completed forms were assessed against the `gold

standard’ . Intra-rater results indicated 98% agreement and

inter-rater reliability 98% agreement. A further 40 triallists

completed injury report forms in situ, resulting in inter-rater

reliability agreement of 98%. This research has provided a

valid instrument for data collection in Rugby Union.

The science of safe scrum m aging

P.D. Milburn

University of Otago, Dunedin, New Zealand

Many proposals have been put forward as a means of reducing

the risk of serious spinal injury in scrummaging: reducing

the number of players, sequential or staggered engagement,

diV erent binding techniques, reducing the incidence of

scrums, ̀ depowering’ , and improved player management. This

report is an overview of a programme of research into the

biomechanics of scrummaging to estimate the forces players

are exposed to. Twenty-six variations of scrum formation and/

or binding were assessed with players scrummaging against an

instrumented scrum machine. The vertical and lateral shear

forces, together with the forward forces, were simultaneously

recorded on each front-row player at engagement and

throughout the `second-shove’ . Forward packs of diV ering

ability, from high school to international teams, were assessed

under normal and altered scrummaging conditions. The

W ndings showed engagement force was independent of the

number and/or level of players and the scrum formation, that

scrum safety was related to strength, experience and skill, that

stability of the scrum was dependent on experience, and that

the small diV erences between scrums did not warrant whole-

sale changes to the way scrums were formed.

Three-dim ensional kinetics of inside and instep soccer

kicks

H. Nunome,1 Y. Ikegami,1 T. Asai2 and Y. Sato1

1Nagoya University, Nagoya and

2Yamagata University, Yamagata, Japan

Qualitative information about inside and instep kicks is

limited. To enhance the quality of performance and evaluate

the stress on joints or bones, it is necessary to identify the

kinetic aspects of these kicking motions. This study was

designed to establish the kinetic features of two kicking

motions, inside and instep kicks, using a three-dimensional

video analysis technique. Five male high-school players volun-

teered to participate in the study. Their kicking motions were

sampled by two high-speed video cameras (Nac MEMRE-

CAM C2) at 200 Hz. The direct linear transformation method

was used to obtain 3-D space coordinates of the trunk and the

kicking leg. Joint torque generated at each joint was computed

by a three-link kinetic chain composed of thigh, shank and

foot. For the inside kick, all participants exhibited external

rotation torque at the hip joint, and its magnitude was com-

parable to that of Xexion at the hip joint and extension at the

knee joint. In contrast, for the instep kick, external rotation

torque at the hip joint was much less than that of Xexion at

the hip and extension at the knee. The results indicate that a

relatively complicated series of rotational motions are required

in the inside kick, suggesting that positively generated torque

for hip external rotation in the inside kick plays an important

role in the execution of a swing by the kicking leg. This W nding

may also help to estimate the possibility of lesion at the hip

joint related to over-practice of these kicking motions.

M uscle activity during the drop punt kick

J. Orchard, S. Walt, A. McIntosh and D. Garlick

University of New South Wales, Sydney, Australia

Punt kicking is a primary technique in Australian Rules foot-

ball and Gaelic football and a secondary technique used by

speciW c positional players in Rugby Union, Rugby League,

soccer and American Football. Four professional Australian

Football League (AFL) players were W lmed performing six

right-foot and six left-foot drop punt kicks while electro-

myograms of seven muscle groups (bilateral quadriceps, ham-

strings and gluteals and rectus abdominus) were obtained

with surface electrodes. The kicking motion was divided into

the phases of (1) run-up/approach, (2) backswing, (3) wind-

up, (4) forward swing, (5) follow-through and (6) recovery.

Punt kicking is a throw-like motion, with much of the work

performed eccentrically in the early phases by proximal

muscle groups and the resulting momentum transferred to


distal segments just before ball contact. The most active

muscle group studied was the quadriceps of the kicking leg,

which acted eccentrically in the wind-up phase and then con-

centrically in the forward swing. The hamstrings of the kicking

leg concentrically initiated the backswing and showed variable

eccentric activity during the follow-through. There was little

diV erence between EMG proW les for right- and left-foot

kicks. High activities in the kicking leg’ s quadriceps, stance

leg’ s gluteal and rectus abdominus, and both hamstrings

help explain the high rates of muscular injuries in the

AFL. The results are similar to previous W ndings in soccer

kicking (Bollens et al., 1987: In B iomechanics X-A , edited by

B. Jonsson, pp. 283 ± 288. Champaign, IL: Human Kinetics).

Kinematic m odel of kicking perform ance for the

preferred and non-preferred leg in m ale soccer

players

B.L. Patritti, A. Lees and A.M. Nevill



It is advantageous to soccer players’ performance to be equally

proW cient at kicking with both the preferred and non-preferred

kicking leg. Sources of kinematic asymmetries when kicking

with the preferred and non-preferred leg have been identiW ed

to persist in the motion characteristics of the shank (Patritti

and Lees, 1999: Journal of Spor ts Science s, 17, 8± 9). The aims

of the present study were to assess the kinematic predictors of

kicking performance for the maximum velocity instep kick

executed with the preferred and non-preferred leg in a group

of male soccer players, and to determine whether diV erent

mechanisms contribute to successful performance of the kick.

Ten amateur male soccer players (mean age 25.2 years,

body mass 73.9 kg, height 177 cm) participated in the study.

A MacReXex opto-electronic recording system (Qualisys

AB, Partille, Sweden), comprising four high-resolution CCD

video cameras and processors (sample rate = 120 Hz; shutter

speed = 1/4000 s), was used to record each kick. All partici-

pants performed W ve maximum velocity instep kicks per

kicking leg, from a two-step approach. Maximal ball speed was

used as a measure of kick performance and recorded using a

JUGS speed gun (Decatur Electronics Inc., IL, USA). The

kinematic characteristics of the kick were described by the

angular displacement of the thigh and shank in the sagittal,

frontal and transverse planes, and linear and angular velocities

of the segments of the kicking leg. Predictors of kicking per-

formance were selected from a set of 47 kinematic variables

using a multiple stepwise regression followed by a best subsets

regression. The best subset for each kicking leg was input to a

regression model with signiW cance set at a= 0.05.

A performance diV erence was found in ball speed, with

that for the preferred leg (23.05 ± 1.23 m ´ s - 1) being sig-

niW cantly greater than that for the non-preferred leg

(21.10 ± 1.30 m ´ s - 1, P = 0.0001). Table 1 outlines the per-

formance models for the preferred and non-preferred kicking

leg with all regression coeY cients being signiW cant (P £ 0.001

and P < 0.05, respectively).

Distal joint velocities were the main predictors for both

models of kicking performance, highlighting the mechanism

of developing a high endpoint velocity of the kicking leg

at impact with the ball. The foot-to-ball speed ratio for the

preferred kicking leg model (1.19) was very similar to that

reported for maximal instep kicking (1.2) (Lees and Nolan,

1998: Journal of Sports Science s, 16, 211± 234). The range of

motion of the shank to ball contact is important to kicking

performance, as a greater foot velocity may be developed

through increased knee Xexion. Maximal withdrawal of the

pelvis had a detrimental inXuence on performance for the

non-preferred leg, reXecting a possible control aspect over

the path of the foot and point of contact on the ball at

impact. For both the preferred and non-preferred legs, kine-

matic analysis indicates a similar mechanism of high distal

velocities contributes signiW cantly to kicking performance.

However, the ability to attain greater distal velocities with the

preferred leg (Patritti and Lees, 1999) may partly account for

the performance asymmetry that exists.

A prospective cohort study of risk factors for injury in

Rugby Union

K.L. Quarrie, J. Alsop, A.E. Waller, Y.N. Bird, S. Marshall and

D.J. Chalmers


New Zealand

Although information about the nature (e.g. site, type and

severity) of rugby injuries is available, little epidemiological

work has been presented to examine risk factors for rugby

injury. To examine the association between potential pre-

season risk factors for rugby and both injury incidence rate

and proportion of playing season missed, a prospective study

was undertaken. A cohort of 258 male rugby players

(mean ± s: age 20.6 ± 3.6 years) from a range of grades was

followed through their entire competitive season. At a

pre-season assessment, information about the following

risk factors was obtained via a questionnaire: demographic

characteristics, health and lifestyle patterns (e.g. stress, alcohol

and cigarette use), rugby playing experience, injury experi-

ence and training patterns. Subsequently, the players had

anthropometric measurements taken, and completed a bat-

tery of W tness tests. SigniW cant multivariate associations with

Table 1. Models of kicking performance for the preferred and

non-preferred kicking leg

Standard error

Regression equation about regression R2

Preferred kicking leg

Ball speed = 2.10 + 1.19*toe_vel_bc +7.00*support_foot_position + 0.0309 *

shank_rom_bc 0.64 81%

Non-preferred kicking leg

Ball speed = 16.1 + 0.607*max_ankle_

vel - 0.0223*max_pelvic_withdrawal 0.66 80%


incidence rate were observed for grade (senior A players had a

higher injury rate than under-19 players: odds ratio = 2.3; 95%

CI 1.6± 3.5), and injury status at the pre-season assessment

(players who were not injured reported a lower incidence rate

than those who were: odds ratio = 0.7; 95% CI 0.5 ± 0.9). Sig-

niW cant multivariate associations with proportion of playing

season missed were observed for position (inside backs missed

less playing time than outside backs: odds ratio = 0.4; 95% CI

0.2 ± 1.0), pre-season injury status (non-injured players missed

less playing time than injured players: odds ratio = 0.2; 95%

CI 0.3 ± 0.9), hours of strenuous physical activity per week

(players who were physically active 40 h per week or more

missed more playing time than those who were less active:

odds ratio = 3.3; 95% CI 1.3± 10.0), body mass index (BMI)

(players whose BMI was less than 23 missed more playing

time than those whose BMI was 28 or more: odds ratio = 4.1;

95% CI = 1.6 ± 10.4) and cigarette smoking (non-smokers

missed signiW cantly less play than smokers: odds ratio = 0.3;

95% CI 0.2 ± 0.5). The results indicate that although incidence

rate and proportion of playing season missed are generally

associated with diV erent risk factors, pre-season injury status

is an important predictor of both among rugby players. The

W ndings emphasize the need for complete rehabilitation from

injury before participation is resumed.

Comparison of cur ve kick with instep kick by 3-D

m otion analysis

H. Sato,1 T. Asai,1 S. Miyashita,2 M. Mouri,2 Y. Oomori2 and

Y. Ooshima2

1Yamagata University, Yamagata and

2Yamagata Prefectural College of

Health and Medical Sciences, Yamagata, Japan

Motion analysis of kicking has been studied by several

investigators (Roberts and Metcalfe, 1968: In B iomechanics,

edited by J. Wartenweiler and E. Jokl, pp. 315± 319. Basel:

Karger; Plagenhoef, 1971: Patterns of Human M otion: A

Cinematographic Analysis, pp. 98± 116. Englewood CliV s, NJ:

Prentice-Hall). These studies have focused on kinematic

analysis of the instep kick. Also, dynamic analysis of the joint

force or torque in the instep kick was performed by Zernicke

and Roberts (1978: Medicine and Science in Sports, 10, 21± 26).

However, there have been few studies of curve ball kicking in

soccer. The aim of this study was to clarify the characteristics

of the infront curve kick, the outfront curve kick and the instep

straight kick using a 3-D motion capture system (Vicon 370).

Three university football players participated. They directed

the ìnfront’ curve kick, the òutfront’ curve kick and the

instep straight kick towards a target area 5 m away. The seven

motion capture cameras (200 Hz) were set up around the

participant, and 18 digitized reXectors were attached to the

joints of the participant. The ball used in this experiment

was an oY cial FIFA ball (434.6 g, 90,000 Pa). Moreover, two

Kistler force plates were set up on the Xoor to analyse the

contact foot at kicking.

The mean angles of the ankle joint, knee, heel and toe of

the kicking leg before impact showed that the ìnfront’ curve

kick was 94.3°, the òutfront’ curve kick was 89.7° and the

instep straight kick was 76.3°. In the same way, the mean angle

of the knee joint was 120° in the ìnfront’ curve kick, 121.7° in

the òutfront’ curve kick and 127.7° in the instep straight

kick. The width of swing from top view in the kicking leg

indicated the ìnfront’ curve kick was 1161 mm, the òutfront’

curve kick was 1088 mm and the instep straight kick was 1009

mm. This result depends on the swing of the curve kick being

wider than that of the straight kick and relates to the angle of

the ankle joint.

EV ects of sole conW guration on ground reaction forces

m easured on natural turf during soccer-speciW c

actions

N. Smith, R. Dyson and T. Hale

Chichester Institute of Higher Education, Chichester, UK

In recent years, many soccer boot manufacturers have

developed outsoles which provide the soccer player with an

alternative to the conventional six-studded pattern. QuantiW -

cation of the forces acting at the boot± turf interface would aid

understanding of the inXuence of boot design. A mounting

rig for a Kistler force plate was designed and constructed in a

natural turf surface. Eight male, right-footed soccer players

(mean ± s: age 24.4 ± 3.1 years, body mass 78.3 ± 9.1 kg)

performed W ve trials of three soccer-speciW c moves (CryV

turn, drag-back turn, shot) with the left foot on a Kistler

force platform with natural turf cover (35 mm). Mizuno Pro

Model and Adidas Equipment Velez Traxion soccer boots

were tested at an approach speed of 3.3 ± 0.3 m ´s - 1. Data were

collected and sampled at 1000 Hz using Kistler Bioware

3.0 software.

Vertical force, braking and propulsion forces, and medial

and lateral forces were normalized for each player’ s body

weight (BW) and compared statistically between boots using

a paired t-test (Table 1). SigniW cant diV erences in ground

reaction force were evident between the standard six-stud

Mizuno Pro model and the Adidas Traxion. The Adidas

Traxion stud conW guration resulted in signiW cantly (P < 0.05)

lower peak vertical ground reaction forces in all actions. The

Adidas Traxion outsoles showed higher medial (P < 0.001)

and lateral (P = 0.04) forces during the shot, suggesting the

boot provided a more stable base for shooting. It is evident

that soccer boot sole conW guration alters ground reaction

forces during soccer-speciW c moves, which has implications

for the performance of soccer skills and the predisposition to

injury of the soccer player. The natural turf instrumentation

rig enabled comparison of ground reaction force measures of

players in an ecological soccer environment.

Table 1. Maximum ground reaction forces for both types of boot

(mean ± s)

Shot CryV Drag-back

Vertical force

Braking force

Medial force

3.95BW ± 0.09

1.27BW ± 0.06

0.80BW ± 0.04

2.30BW ± 0.09

1.02BW ± 0.10

0.31BW ± 0.02

2.23BW ± 0.07

1.23BW ± 0.12

0.23BW ± 0.07


Osteitis pubis in Australian Rules footballers: A stress

injury to the pubic bone

G. Verrall, J. Slavotinek and G. Fon

Sportsmed SA, Adelaide, Australia

The diagnosis and treatment of chronic groin pain are diY cult.

One of the common diagnoses is osteitis pubis. The aim of

this research was to determine in elite Australian Rules foot-

ballers (ARF): (1) the prevalence of bone marrow oedema and

other changes of the pubic symphysis using a MRI scan; (2)

the relationship between clinical features and MRI scan

changes.

Eighty-nine elite ARF players were recruited for the study

and underwent a comprehensive musculoskeletal examination

of the groin region followed by a clinical history of groin pain

taken by direct interview. They then underwent a MRI scan.

The participants were blinded to the examiner and to the

two reporting radiologists. Additionally, 17 umpires acted as

`running’ controls and 10 sedentary males were recruited.

A total of 116 individuals had a MRI scan of their groin

area (1.5T GE Sigma, 1.0T Siemens) with T1 and T2 fat

suppressed views.

Results showed a signiW cant correlation (P < 0.03) between

currently symptomatic athletes (47/89, 53%) with marrow

oedema graded as severe grade III (33/89, 37%). Results

showed a signiW cant correlation (P < 0.01) between previously

symptomatic athletes (60/89, 67%) and a previous severe

episode of groin pain (33/89, 37%), with changes seen on the

MRI scan consistent with previous injury to the pubic bone

area: cysts 28/89 (31%), Xuid in symphysial discs 13/89

(15%), Xuid/fracture lines 5/89 (6%), pubic symphysial

disc irregularity 70/89 (79%), and superior pubic ligament

hypertrophy 38/89 (43%).

From these results, we conclude that groin pain in

Australian Rules footballers is strongly associated with bone

marrow oedema and its sequelae. The sequelae include cyst

formation and the appearance of Xuid/fracture lines. A logical

model to explain this sequence of events is the development

of a tension stress fracture of the pubic ramus.

communications to the fourth world congress of science and football

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