kinematic comparisons of 1996 olympic baseball pitchers

Kinematic comparisons of 1996 Olympic baseballpitchers

RAFAEL F. ESCAMILLA,1* GLENN S. FLEISIG,2 NIGEL ZHENG,2

STEVEN W. BARRENTINE2 and JAMES R. ANDREWS2

1Michael W. Krzyzewski Human Performance Laboratory, Duke University Medical Center, PO Box 3435,

Durham, NC 27710 and 2American Sports Medicine Institute, 1313 13th Street South, Birmingham, AL 35205, USA

Accepted 11 February 2001

The aim of this study was to compare and evaluate the kinematics of baseball pitchers who participated in the1996 XXVI Centennial Olympic Games. Two synchronized video cameras operating at 120 Hz were used tovideo 48 pitchers from Australia, Japan, the Netherlands, Cuba, Italy, Korea, Nicaragua and the USA. Allpitchers were analysed while throwing the fastball pitch. Twenty-one kinematic parameters were measured atlead foot contact, during the arm cocking and arm acceleration phases, and at the instant of ball release. Theseparameters included stride length, foot angle and foot placement; shoulder abduction, shoulder horizontaladduction and shoulder external rotation; knee and elbow ¯ exion; upper torso, shoulder internal rotation andelbow extension angular velocities; forward and lateral trunk tilt; and ball speed. A one-way analysis of variance(P < 0.01) was used to assess kinematic diþ erences. Shoulder horizontal adduction and shoulder externalrotation at lead foot contact and ball speed at the instant of ball release were signi® cantly diþ erent amongcountries. The greater shoulder horizontal abduction observed in Cuban pitchers at lead foot contact is thoughtto be an important factor in the generation of force throughout the arm cocking and arm acceleration phases,and may in part explain why Cuban pitchers generated the greatest ball release speed. We conclude thatpitching kinematics are similar among baseball pitchers from diþ erent countries.

Keywords: biomechanics, fastball, pitching, throwing.

Introduction

Baseball is a relatively new Olympic sport, havingmade its debut at the 1992 Barcelona Olympic Games.International baseball teams compete in regionalcompetitions to determine which teams advance to theOlympic Games. Five regions have been identi® edby the International Olympic Committee for inter-national baseball competition (Osinski, 1998): Africa,the Americas, Asia, Europe and Oceania. For the 1996Olympics, all of these regions were represented exceptAfrica.

Pitching kinematics are instilled in a pitcher at ayoung age in junior league baseball and reinforcedthroughout the pitcher’ s baseball career (Thurston,1998). Although an adult pitcher’ s morphology cannotbe altered, muscular strength and pitching kinematics,

* Author to whom all correspondence should be addressed. e-mail:[email protected]

such as joint and segment angles, positions andvelocities, can be altered to help improve performance.Although baseball pitching kinematics have been welldocumented (Barrentine et al., 1998; Escamilla et al.,1998), much of this research focused on Americanbaseball pitchers. There are limited data to comparepitching mechanics between diþ erent countries andcultures. Some pitching kinematic parameters havebeen quanti® ed for Japanese (Sakurai et al., 1993),Australian (Elliott et al., 1986) and Korean (Hanet al., 1996) collegiate and professional pitchers. How-ever, shoulder abduction, elbow angle and ball speedwere the only kinematic parameters these studieshad in common. In addition, all studies in the literaturethat involve biomechanical analyses of baseball pitchingwere performed in simulated conditions; no studies haveanalysed pitching biomechanics during competition.As it is likely that pitching mechanics may be slightlydiþ erent in laboratory-simulated conditions thanduring a game, the results of the current study provide

Journal of Sports Sciences, 2001, 19, 665± 676

Journal of Sports Sciences ISSN 0264-0414 print/ISSN 1466-447X online Ó 2001 Taylor & Francis Ltdhttp://www.tandf.co.uk/journals

a database for high-standard pitchers from severalcountries who were analysed during competition.

Knowledge of diþ erences in pitching mechanicsamong players from diþ erent countries is valuableto coaches, trainers and biomechanists in learningstrategies for selecting optimal kinematics for athleticperformance. Many coaches believe that pitchingmechanics are taught diþ erently in diþ erent countries(Osinski, 1998; Thurston, 1998), which may result indiþ erences in pitching kinematics. Several kinematicparameters, such as knee ¯ exion, shoulder externalrotation, elbow ¯ exion and shoulder abduction, havebeen reported as being diþ erent between Korean pro-fessional pitchers and American professional pitchers(Han et al., 1996). We hypothesized that kinematicdiþ erences, which may be due to diverse coaching andtraining methodologies or to diþ erent anthropometriccharacteristics (e.g. body heights and arm lengths),would be found among baseball pitchers from variouscountries and cultures. The aim of this study was tocompare preferred pitching kinematics among elitebaseball pitchers from the eight countries that partici-pated in the 1996 XXVI Centennial Olympic Games.

Methods

Fulton County Stadium in Atlanta, Georgia was thebaseball venue for the 1996 XXVI Centennial OlympicGames. The eight countries that participated in theOlympic baseball competition were Australia, Japan,Korea, Italy, Cuba, the Netherlands, Nicaragua andthe USA. Since professional baseball pitchers werenot allowed to participate in the Olympics, all partici-pants were considered amateurs. As all eight countriesexcept Cuba have professional baseball leagues andprofessional pitchers who pitch in those leagues, thepitchers studied do not represent the best pitchers fromtheir respective countries.

Sixteen Olympic baseball games were videotaped overa 6-day period, with each country playing at least threegames. Two synchronized high-speed video cameras(Peak Performance Technologies, Inc., Englewood,CO) collected data at a rate of 120 Hz. For each camera,

the shutter speed was set at 0.001 s and the aperture wasadjusted according to weather conditions. Each camerawas positioned approximately 50 m from the pitchingmound with views from behind home plate and thirdbase. Views from each camera were adjusted to capturethe entire pitching motion while optimizing the ® eldof view. Video data were collected from 48 of the 59pitchers listed on the rosters of the eight countriesparticipating in the baseball competition. Of these 48pitchers, 35 were right-handed and 13 were left-handed.Body mass, height, age and arm length were measured(Table 1); however, body mass was not available forpitchers from Italy, Korea, Nicaragua and the USA.Ball speed was recorded using a Jugs Tribar Sport radargun (Jugs Pitching Machine Company, Tualatin, OR) asthe ball left the pitcher’ s hand. Pitch type (i.e. fastball,curveball, change-up, slider, etc.) was determinedthrough a combination of video analysis and from ballspeed. Ball speed is highest during the fastball pitch,which is typically 3± 5 m´s-1 faster than the slider and5± 7 m ´s-1 faster than the curveball and change-up(Escamilla et al., 1998). Only the fastball pitch wasanalysed in this study. Each pitch thrown was recordedas either a ball or strike.

A 2 ´ 1.5 ´ 1 m three-dimensional calibration frame(Peak Performance Technologies, Inc., Englewood,CO), surveyed with a measurement tolerance of 0.005m, was recorded before and after the participants werevideotaped. The calibration frame was positioned on thebaseball mound in the same volume occupied by thebaseball pitcher during the portion of the pitch fromlead foot contact to the instant of ball release. It com-prised 24 spherical balls of known spatial coordinates,with the x- and z-axes positioned parallel to the groundand the y-axis pointing vertically. The x-axis of theframe was 2 m long and pointed from the pitchingrubber to home plate. The z-axis was the vector cross-product of the x-axis and y-axis. Since kinematicparameters were measured only from lead foot contactto the instant of ball release, and not during the wind-up, stride, arm deceleration and follow-through phases,the 2 ´ 1.5 ´ 1 m volume was large enough to containthe portion of pitching motion from lead foot contact tothe instant of ball release.

Table 1. Physical characteristics of the pitchers (mean ± s)

Australia(n = 8)

Italy(n = 8)

Netherlands(n = 6)

Japan(n = 6)

Korea(n = 6)

USA(n = 5)

Cuba(n = 5)

Nicaragua(n = 4)

Body mass (kg)Height (m)Age (years)Arm length (m)

84 ± 101.85 ± 0.08

24 ± 30.63 ± 0.06

-1.87 ± 0.10

29 ± 50.60 ± 0.06

84 ± 81.87 ± 0.06

28 ± 60.64 ± 0.06

78 ± 51.80 ± 0.07

24 ± 40.56 ± 0.03

-1.85 ± 0.06

22 ± 20.64 ± 0.08

-1.91 ± 0.11

21 ± 10.64 ± 0.07

86 ± 51.88 ± 0.04

26 ± 20.65 ± 0.06

-1.79 ± 0.03

28 ± 70.59 ± 0.02

666 Escamilla et al.

To minimize the eþ ects of fatigue, all pitching trialsthat were chosen for analysis were selected from the® rst three innings a pitcher threw. For each pitcher,the three fastballs that were thrown for strikes andrecorded the highest ball release speeds were chosen forkinematic analysis. A three-dimensional video system(Peak Performance Technologies, Inc., Englewood,CO) was used to manually digitize the data from eachcamera view for all 48 participants. A 14-point spatialmodel was created, consisting of the centres of the leftand right mid-toes (third metatarsophalangeal joints),ankles, knees, hips, shoulders, elbows and wrists.Each of these 14 points was digitized in every video ® eld(120 Hz). Since these points were digitized throughclothing and not from external markers, it was impor-tant to perform reliability and validity tests to determinedigitizing accuracy and the validity of the results. Totest for digitizing reliability, a single digitizer was able todigitize three separate trials so that segment lengthsvariations were 0.01± 0.02 m diþ erent for the threetrials. Three diþ erent digitizers were then used todigitize the three trials for each participant (each trialbeing digitized by a diþ erent digitizer), with variationsin segment lengths (e.g. thigh, leg, upper arm andforearm segments) also 0.01± 0.02 m diþ erent for thethree trials. For example, the humerus segment (elbowto shoulder) was approximately 0.30 m long and thethigh segment was approximately 0.50 m long. A dif-ference of 0.01± 0.02 m between or within digitizerswould yield a digitized length diþ erence of 2± 6%. Totest the validity of the kinematic measurements,the results of the current study will be comparedwith similar kinematic results from the literature inwhich external markers were and were not used duringbaseball pitching.

Using the direct linear transformation method(Wood and Marshall, 1986), three-dimensional co-ordinate data were derived from the two-dimensionaldigitized images from each camera view. An averageroot mean square calibration error of 0.0076 m wasproduced. The data were ® ltered with a Butterworthlow-pass ® lter with a cut-oþ frequency of 13.4 Hz(Fleisig et al., 1996; Escamilla et al., 1998). A computerprogram was written to calculate kinematic parameters.The ® ve-point central diþ erence method was usedto calculate maximum upper torso angular velocityand maximum shoulder internal rotation angularvelocity.

The pitching motion was divided into several phasesas previously de® ned (Fleisig et al., 1996; Escamillaet al., 1998). Using methods previously described(Feltner, 1989; Fleisig et al., 1996; Escamilla et al.,1998), 21 kinematic parameters were calculated at leadfoot contact (when the lead foot initially contacted thepitching mound), during arm cocking (from lead foot

contact to maximum shoulder external rotation), duringarm acceleration (from maximum shoulder externalrotation to the instant of ball release) and at the instantof ball release. Angle conventions are shown in Fig. 1. Atlead foot contact, eight kinematic parameters weremeasured on the pitching arm and lead leg. First, stridelength was de® ned as the linear distance from the stanceankle to the lead ankle. Secondly, foot placement wasde® ned as the mediolateral displacement between thelead ankle and stance ankle. For a right-handed pitcher,an open (positive) foot placement occurred when hislead ankle was to the left of his stance ankle, and a closed(negative) foot placement occurred when his lead anklewas to the right of his stance ankle. Thirdly, foot anglewas de® ned as the angle between the longitudinalaxis of the foot and a vector pointing from the centreof the pitching rubber to the centre of home plate. Fora right-handed pitcher, an open (positive) foot angleoccurred when the lead foot pointed to the left ofthe straight-ahead position, and a closed (negative)foot angle occurred when the lead foot pointed tothe right of the straight-ahead position. The other ® veparameters were elbow ̄ exion angle (Fig. 1A), shoulderexternal rotation (Fig. 1B), shoulder abduction(Fig. 1C), shoulder horizontal adduction (Fig. 1D)and knee ¯ exion angle (Fig. 1E). Four kinematicparameters were measured during the arm cockingphase: maximum upper torso angular velocity (Fig. 1H),maximum elbow ̄ exion, maximum shoulder horizontaladduction and maximum shoulder external rotation.Three kinematic parameters were measured duringthe arm acceleration phase: maximum elbow extensionangular velocity, maximum shoulder internal rotationangular velocity and average shoulder abduction duringthe arm acceleration phase. At the instant of ball release,six kinematic parameters were measured: knee ¯ exionangle, forward trunk tilt (the trunk angle to the verticalin the x-y plane; Fig. 1F), lateral trunk tilt (the trunkangle to the vertical in the y-z plane; Fig. 1G), elbow¯ exion angle, shoulder horizontal adduction and ballspeed.

Five temporal variables were chosen for analysis aspreviously described (Fleisig et al., 1996, 1999): timeto maximum upper torso angular velocity, time tomaximum elbow ¯ exion, time to maximum shoulderexternal rotation, time to maximum angular velocity ofelbow extension and time to maximum angular velocityof shoulder internal rotation. The temporal variablesrepresent the timing of these ® ve kinematic measure-ments during the arm cocking and arm accelerationphases of the pitch. Each temporal value representeda percentage of the pitch completed, measured fromlead foot contact to the kinematic parameter given,where 0% corresponds to lead foot contact and 100%corresponds to the instant of ball release.

Kinematic comparisons of Olympic baseball pitchers 667

Fig. 1. De® nition of kinematic parameters, calculated in three-dimensional space: (A) elbow ¯ exion; (B) shoulder external/internal rotation; (C) shoulder abduction; (D) shoulder horizontal abduction (negative)/shoulder horizontal adduction (positive);(E) lead knee ¯ exion; (F) forward trunk tilt; (G) lateral trunk tilt; (H) upper torso angular velocity (vUT). Reprinted withpermission from Escamilla et al. (1998).

The kinematic data for the three trials for each pitcherwere averaged. A one-way analysis of variance was usedto assess kinematic and temporal diþ erences (P < 0.01)among pitchers from diþ erent countries, while Tukey’ sHonestly Signi® cant Diþ erence post-hoc test (modi® edto compare any two groups with unequal group sizes)was used to assess pairwise comparison diþ erences(P < 0.01). The pitchers were then grouped into fourgeographical regions (the Americas, Europe, Asia andOceania) and the diþ erences were re-analysed. An alphalevel per comparison of 0.01 was chosen to reduce theType I error rate for the set of comparisons while notdramatically in¯ ating the Type II error rate.

Results and discussion

Only three of the 21 kinematic parameters quanti® edwere signi® cantly diþ erent among pitchers from theeight countries (Table 2). When pitchers from theseeight countries were combined into four geographical

regions, only two of the 21 kinematic parametersquanti® ed were signi® cantly diþ erent (Table 3). Sinceover 80% of the kinematic parameters were not signi® -cantly diþ erent among pitchers from the eight countriesand among pitchers from the four geographicalregions, pitching kinematics appear to be similar amongOlympic baseball pitchers from diþ erent countries andgeographical regions. However, the small sample ofpitchers from each country (each team only had 6± 8pitchers on their roster) may have limited the statisticalpower required to detect signi® cant diþ erences.Kinematic comparisons between the current study andthe pitching literature are shown in Tables 4 and 5.

There were no signi® cant diþ erences in temporalmeasurements between countries (Table 6). The tem-poral values in the current study were similar tothose reported previously for these same kinematicparameters (Fleisig et al., 1996, 1999). Fleisig et al.(1999) previously reported no signi® cant diþ erencesamong youth, high school, college and professionalpitchers for the same temporal measurements as in the


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586

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333

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237

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234

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227

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Table 3. Kinematic comparisons of 1996 Olympic baseball pitchers by geographical region (mean ± s)

ParameterOceania(n = 8)

Europe(n = 14)

Asia(n = 12)

The Americas(n = 14) P-value

Lead foot contact

Stride length (m)Stride length (%ht)Foot placement (m)Foot angle (°)Shoulder abduction (°)Shoulder horizontal adduction (°)Shoulder external rotation (°)Knee ̄ exion (°)Elbow ¯ exion (°)

1.51 ± 0.1582 ± 7

-0.06 ± 0.0514 ± 1690 ± 8

-25 ± 1265 ± 25**64 ± 692 ± 20

1.51 ± 0.1081 ± 6

-0.07 ± 0.0614 ± 1591 ± 11

-26 ± 1039 ± 22**a

65 ± 678 ± 26

1.56 ± 0.0885 ± 4

-0.04 ± 0.056 ± 13

93 ± 8-20 ± 1128 ± 21**a,b

64 ± 874 ± 26

1.49 ± 0.1080 ± 4

-0.04 ± 0.0419 ± 1392 ± 8

-30 ± 1454 ± 17**63 ± 797 ± 21

0.4670.0890.5320.2170.8790.2520.001*0.9670.066

Arm cocking phase

Maximum upper torso angular velocity(rad ´s-1)

Maximum elbow ¯ exion (°)Maximum shoulder horizontal adduction (°)Maximum shoulder external rotation (°)

23.0 ± 4.0109 ± 1310 ± 5

187 ± 8

24.6 ± 3.0109 ± 12

12 ± 8183 ± 9

26.2 ± 3.7111 ± 16

11 ± 9186 ± 12

24.8 ± 3.3108 ± 21

18 ± 9184 ± 10

0.2450.9660.1060.771

Arm acceleration phase

Maximum shoulder internal rotation angularvelocity (rad ´s-1)

Maximum elbow extension angular velocity(rad ´s-1)

Average shoulder abduction (°)

108.6 ± 21.8

45.0 ± 4.489 ± 6

102.3 ± 34.6

45.2 ± 9.690 ± 9

114.8 ± 25.0

53.2 ± 4.291 ± 14

103.7 ± 23.4

49.4 ± 7.585 ± 12

0.665

0.0510.430

Instant of ball release

Knee ̄ exion (°)Elbow ¯ exion (°)Forward trunk tilt (°)Lateral trunk tilt (°)Shoulder horizontal adduction (°)Ball speed (m´s-1)

67 ± 717 ± 437 ± 630 ± 10

8 ± 636 ± 2**b

64 ± 621 ± 731 ± 1222 ± 910 ± 636 ± 1**b,c

66 ± 720 ± 1035 ± 1730 ± 17

9 ± 1037 ± 1**

64 ± 821 ± 634 ± 1527 ± 1516 ± 1038 ± 2**

0.6020.6070.8710.5950.168

< 0.001*

* Signi® cant diþ erence (P < 0.01) among countries. ** Signi® cant diþ erence (P < 0.01) of post-hoc (Tukey’ s Honestly Signi® cant Diþ erence)pairwise comparisons. a Signi® cantly diþ erent than Oceania. b Signi® cantly diþ erent than the Americas. c Signi® cantly diþ erent than Asia.Note: Oceania represents Australia; Europe represents Italy and the Netherlands; Asia represents Japan and Korea; The Americas representsCuba, Nicaragua and USA.

current study. It can be inferred from these temporaldata that the timing of when these maximum kinematicparameters occur is similar for pitchers of variousstandards and from diþ erent countries.

Cuban and American pitchers exhibited signi® -cantly greater ball release speed than pitchers from theNetherlands, Nicaragua, Australia and Italy. At leadfoot contact, Cuban pitchers demonstrated signi® cantlygreater horizontal shoulder abduction than pitchersfrom Japan, USA, Italy and Korea, while Japanesepitchers showed signi® cantly less shoulder externalrotation than Australian and Nicaraguan pitchers. Themean shoulder horizontal adduction angle of -45° (i.e.45° shoulder horizontal abduction) for the Cubanpitchers at lead foot contact is considerably greater than

previously reported (-17° to -20°) for collegiatepitchers throwing the fastball (Feltner, 1989; Sakuraiet al., 1993; Fleisig et al., 1996; Escamilla et al., 1998).The greater shoulder horizontal abduction exhibited byCuban pitchers may pre-stretch their anterior shouldermusculature (e.g. pectoralis major, anterior deltoids)more than pitchers from Japan, USA, Italy and Korea.This may position the throwing arm in a more eþ ectiveposition to generate force throughout the remainderof the pitch, which may partially explain why Cubanpitchers generated the greatest ball release speed.However, this can only be a partial explanation,since the American pitchers attained equal throwingspeeds with signi® cantly less horizontal abductionthan Cuban pitchers. In addition, although they had


similar ranges of horizontal abduction to Cubanpitchers, the Australian, Nicaraguan and Dutch pitchershad signi® cantly slower throwing speeds. Nevertheless,increased horizontal abduction may help prevent thearm from moving towards the target prematurely duringthe arm cocking phase of the pitch. Neal et al. (1991)reported that less skilled throwers move their throwingarm towards the target prematurely, thereby losing theeþ ect of pre-stretching the involved muscles enjoyed byhighly skilled throwers.

The anterior shoulder muscles function primarilyas shoulder horizontal adductors and internal rotatorsduring the baseball pitch and have shown moderateactivity during the baseball delivery (Jobe et al., 1983,1984; Gowan et al., 1987). Pre-stretching these musclesduring the early phases of the pitch may store elasticenergy in these tissues, which may be used during thelatter phases of the pitch. The storage and utilizationof elastic energy during the stretch± shortening cyclehave been well documented (Komi and Bosco, 1978;Bosco et al., 1982, 1987) and may enhance bothpassive and active muscle force production in baseballpitching. The importance of the stretch± shorteningcycle has been demonstrated during the javelin throw(Bartlett and Best, 1988; Best et al., 1993; Mero et al.,1994), which has some similarities to baseball pitching.Other plausible factors that have been demonstrated toenhance concentric muscle contractile force subsequentto a pre-stretched or eccentrically contracting muscle arethe myotatic (stretch) re¯ ex and an increase in the rate offorce production (Dietz et al., 1979; Bosco et al., 1982).

Another potential advantage of greater shoulder hori-zontal abduction at lead foot contact is that it causes thethrowing arm to move behind the trunk at this time.This may cause the trunk to rotate towards the throwingarm, thus placing the trunk musculature on stretch.The stored elastic energy from the pre-stretched rectusabdominis, external and internal obliques and para-spinal musculature (e.g. erector spinae, semispinalis,multi® di, rotatores), together with the stretch±shortening cycle that occurs in these muscles during thearm cocking phase, may aid these muscles in generatingtrunk rotation. During the arm cocking phase, moderateto high activity from the rectus abdominis, abdominalobliques and lumbar paraspinal musculature has beenreported in professional baseball pitchers (Watkinset al., 1989). Nevertheless, some baseball coaches donot advocate extreme shoulder horizontal abduction atlead foot contact based on the belief that excessive stressto the throwing shoulder may occur (Thurston, 1998).However, this belief has not been scienti® cally validated.Furthermore, it is diý cult to know the optimal shoulderhorizontal abduction that is needed at lead foot contactto maximize the storage and utilization of elastic energythroughout the remainder of the pitch.

Shoulder external rotation at lead foot contact hasbeen shown to vary widely in the literature (Table 4),ranging from 45° to 106°, and to be usually associatedwith large standard deviations. The value for Japanesepitchers (262°) in the current study is unusually low,implying that they were slow in externally rotating theirthrowing shoulder. This may cause the arm to lagbehind the body during the subsequent arm cockingand arm acceleration phases of the pitch, which mayincrease elbow or shoulder joint forces. Kinetic analysesare needed to test this hypothesis. However, in contrastto the results of the current study, a shoulder externalrotation at lead foot contact of 106 ± 22° (Fig. 1B,Table 4) has previously been reported for six Japaneseuniversity pitchers (Sakurai et al., 1993). Diþ erencesin how lead foot contact was de® ned by ourselves andSakurai et al. (1993) may in part be responsible for thesediscrepancies in shoulder external rotation at lead footcontact.

The greater ball release speed of American andCuban pitchers is supported by data from the 1999World, European and Pan-Am 18-Under tournaments(Clark, 2000), in which pitchers from Cuba (n = 9) andthe USA (n = 9) had an average ball release speed ofabout 38 m ´s-1. In contrast, pitchers from Asia (Japanand Korea, n = 11), Europe (Italy and Netherlands,n = 17) and Australia (n = 6) all had mean ball releasespeeds of about 36 m´s-1. Nevertheless, it is diý cult toinfer from the current study why Cuban and Americanpitchers had signi® cantly greater ball release speedsthan pitchers from Australia, Italy, the Netherlands andNicaragua. Body height and arm length are likely toin¯ uence ball release speed. Although the Cuban andAmerican pitchers were the tallest and had the longestarms in the current study, these diþ erences were notsigni® cant. With a larger sample size of pitchers fromeach country, more kinematic and anthropometricdiþ erences may have been found.

Most of the kinematic parameters that were quanti-® ed in the current study had values similar to fastballdata from many other studies involving high school,college and professional pitchers (Tables 4 and 5).A unique contribution of the current study is that itprovides pitching kinematic data during competitionamong a diverse sample of elite pitchers from diþ erentcountries. All other pitching studies in the literatureinvolved pitchers in an arti® cial pitching environment.

As in the current study, some researchers havemanually digitized joint centres through the baseballuniform without the use of external markers (Pappaset al., 1985a,b; Vaughn, 1985; Feltner and Dapena,1986), while others aý xed external markers to thetrunk and extremities during simulated pitching inlaboratory environments (Elliott et al., 1986; Dillmanet al., 1993; Werner et al., 1993; Fleisig et al., 1996,


Ta

ble

4.

Lin

ear

and

an

gula

r d

isp

lace

men

t co

mp

aris

on

s am

on

g st

ud

ies

invo

lvin

g th

e fa

stb

all p

itch

(m

ean

±s)

Ref

eren

ceP

itch

ers

Sta

nd

ard

Eve

nt

Str

ide

len

gth

(m)

Sh

ou

lder

abd

uct

ion

(°)

Sh

ou

lder

hori

zon

tal

add

uct

ion

(°)

Sh

ou

lder

exte

rnal

rota

tio

n (

° )

Elb

ow

¯ex

ion

(°)

Kn

ee¯

exio

n(°

)

Forw

ard

tru

nk

tilt

(°)

Lat

eral

tru

nk

tilt

(°)

Cu

rren

tst

ud

y 4

8 m

ales

Oly

mp

icL

ead

foot

con

tact

Max

imu

m v

alu

eB

all re

leas

e

1.5

1±

0.1

192

±9

- 26

±1

21

2±

10

10

±1

0

45

±2

41

85

±1

09

6±

25

10

9±

16

20

±7

64

±7

65

±7

34

±1

32

7±

13

Esc

amil

la e

t

al. (

19

98

)1

6 m

ales

Coll

ege

Lea

d f

oot

con

tact

Max

imu

m v

alu

eB

all re

leas

e

1.5

1±

0.0

998

±1

2- 2

0±

10

20

±7

10

±9

52

±3

31

71

±6

84

±17

10

4±

12

24

±5

48

±11

46

±13

28

±5

28

±9

Sak

ura

i et

al.

(19

93)

6 m

ales

Coll

ege

Lea

d f

oot

con

tact

Max

imu

m v

alu

eB

all re

leas

e

83

±1

285

±7

79

±1

0

- 20

±8

11

±1

26

±7

106

±2

21

81

±7

133

±2

3

10

7±

20

95

±13

35

±12

Fel

tner

an

dD

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a(1

98

6)

8 m

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Coll

ege

Lea

d f

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tact

Max

imu

m v

alu

eB

all re

leas

e

76

±9

92

±6

- 18

±8

2±

9

46

±2

31

70

±1

01

13

±2

3

63

±23

91

±8

20

±6

Fle

isig

et

al.

(19

99)

11

5 m

ales

Coll

ege

Lea

d f

oot

con

tact

Max

imu

m v

alu

eB

all re

leas

e

1.5

6±

0.1

12

0±

89

±9

55

±2

91

73

±1

08

5±

18

99

±15

23

±6

48

±12

39

±13

33

±1

0

Fle

isig

et

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(19

99)

60 m

ales

Pro

Lea

d f

oot

con

tact

Max

imu

m v

alu

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all re

leas

e

1.6

1±

0.0

91

7±

99

±1

0

58

±2

61

75

±1

18

7±

15

98

±15

23

±5

46

±8

38

±13

33

±9

Han

et al.

(19

96)

16 m

ales

Pro

Lea

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tact

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m v

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all re

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1.3

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121

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41

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12

141

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9±

18

71

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22

±14

57

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56

±11

54

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34

±9

Pap

pas

et al.

(19

85b

)1

5 m

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Pro

Lea

d f

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tact

Max

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m v

alu

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all re

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90

90

±1

0

- 30

90

±12

01

60

48

90

12

02

4

Ellio

tt e

t al.

(19

86)

6 m

ales

Pro

Lea

d f

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con

tact

Max

imu

m v

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all re

leas

e

1.5

4±

0.0

910

410

13

6±

34

8

Dillm

an e

t

al. (

19

93

)2

9 m

ales

Coll

ege/

pro

Lea

d f

oot

con

tact

Max

imu

m v

alu

eB

all re

leas

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1.4

1±

0.0

891

±1

096

±9

93

±8

- 30

±1

41

4±

60

±5

53

±2

61

78

±1

01

05

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Wer

ner

et

al.

(19

93)

7 m

ales

Coll

ege/

pro

Lea

d f

oot

con

tact

Max

imu

m v

alu

eB

all re

leas

e1

85

85

20

Fle

isig

et

al.

(19

96)

26 m

ales

Coll

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HS

Lea

d f

oot

con

tact

Max

imu

m v

alu

eB

all re

leas

e

1.3

6±

0.0

993

±1

2- 1

7±

12

18

±8

7±

7

67

±2

41

73

±1

09

8±

18

10

0±

13

22

±6

51

±11

40

±12

32

±1

03

4±

9

Vau

ghn

(19

85)

12 m

ales

Coll

ege/

HS

Lea

d f

oot

con

tact

Max

imu

m v

alu

eB

all re

leas

e1

9±

3

Abb

revia

tion

s: H

S=

hig

h s

chool; P

ro=

pro

fess

ion

al.

Table 5. Linear and angular velocity comparisons among studies involving the fastball pitch (mean ± s)

Reference Pitchers Standard

Maximumupper torso

angularvelocity(rad ´s-1)

Maximumelbow extension


Maximum shoulderinternal rotation


Ball speedat the

instant ofrelease(m ´s-1)

CurrentEscamilla et al. (1998)Feltner and Dapena (1986)Fleisig et al. (1999)Fleisig et al. (1999)Han et al. (1996)Pappas et al. (1985b)Elliott et al. (1986)Dillman et al. (1993)Werner et al. (1993)Fleisig et al. (1996)Vaughn (1985)

48 males16 males

8 males115 males60 males16 males15 males

6 males29 males

7 males26 males12 males

OlympicCollegeCollegeCollegeProProProProCollege/proCollege/proCollege/HSCollege/HS

24.8 ± 3.521.3 ± 1.7

20.8 ± 1.720.9 ± 1.418.7 ± 3.7

20.4 ± 1.7

48.2 ± 7.542.6 ± 4.238.4 ± 7.041.5 ± 11.840.5 ± 11.841.7 ± 13.2

80.216.9

40.140.8 ± 11.839.0 ± 6.0

107 ± 27132 ± 19107 ± 12130 ± 22126 ± 19119 ± 19

108

121 ± 19

132 ± 24107 ± 15

37 ± 235 ± 2

3435 ± 237 ± 2

38 ± 136

35 ± 336 ± 2

Abbreviations: HS = high school; Pro = professional.

Table 6. Temporal comparisons of 1996 Olympic baseball pitchers by country (mean ± s)

ParameterAustralia(n = 8)

Italy(n = 8)

Netherlands(n = 6)

Japan(n = 6)

Korea(n = 6)

USA(n = 5)

Cuba(n = 5)

Nicaragua(n = 4)

Maximum upper torso angularvelocity (% of pitch)

Maximum elbow ¯ exion (% of pitch)Maximum shoulder external rotation

(% of pitch)Maximum elbow extension angular

velocity (% of pitch)Maximum shoulder internal rotation

angular velocity (% of pitch)

44 ± 2058 ± 10

78 ± 4

85 ± 5

96 ± 6

46 ± 1462 ± 11

75 ± 9

84 ± 6

99 ± 6

52 ± 1678 ± 11

81 ± 6

87 ± 12

102 ± 14

45 ± 1569 ± 10

76 ± 13

83 ± 17

89 ± 20

52 ± 1049 ± 15

85 ± 4

86 ± 8

105 ± 10

43 ± 1161 ± 16

84 ± 6

87 ± 15

107 ± 11

36 ± 1165 ± 17

84 ± 7

89 ± 26

99 ± 4

45 ± 1570 ± 21

77 ± 10

70 ± 6

108 ± 4

Note: Each temporal value represents a percentage of the pitch completed (measured from lead foot contact to the kinematic parameter given),where 0% corresponds to lead foot contact and 100% corresponds to the instant of ball release. No signi® cant diþ erences (P < 0.01) were foundamong countries.

1999; Escamilla et al., 1998). These methodologicaldiþ erences among studies probably contributed tothe large range of kinematic values speci® ed above. Forexample, mean maximum angular velocity of shoulderinternal rotation among the eight countries in thecurrent study was 107 ± 10 rad ´s-1, which was quitesimilar to the 107 ± 30 rad ´s-1 reported by Feltner andDapena (1986), the 108 rad ´s-1 reported by Pappaset al. (1985b) and the 107 ± 15 rad ´s-1 reported byVaughn (1985), who also manually digitized jointcentres through the baseball uniform without the useof external markers. In contrast, considerably largermean maximum angular velocities of shoulder internalrotation have been reported by Escamilla et al. (1998;132 ± 19 rad ´s-1), Fleisig et al. (1999; 130 ± 22 rad ´s-1),Dillman et al. (1993; 121 ± 19 rad ´s-1) and Fleisig et al.

(1996; 132 ± 24 rad ´s-1), all of whom used externalmarkers aý xed to the trunk and extremities duringsimulated pitching in the laboratory. The main diý cultywith manual digitization during a game is that it involvesestimating joint centres through the baseball uniform,which was a limitation to the current study. However,the many similar kinematic values between the currentstudy and the pitching literature (Tables 4 and 5) helpsvalidate the kinematic values reported here.

Conclusions

Twenty-one pitching kinematic variables weremeasured and compared among pitchers representingeight countries that participated in the 1996 XXVI


Centennial Olympic Games. Since only three kinematicparameters were signi® cantly diþ erent among thepitchers, we conclude that pitching kinematics aresimilar among Olympic baseball pitchers from diþ erentcountries. Nevertheless, the few kinematic diþ erencesthat were observed between countries may in¯ uencepitching performance. Furthermore, diþ erent kine-matics may also aþ ect risk of injury, since shoulder andelbow joint forces may change as pitching kinematicschanges. Additional studies should be conducted toexamine shoulder and elbow kinetics among pitchersfrom diþ erent countries, as well as to assess training andcoaching methods among diþ erent countries.

Acknowledgements

We would like to acknowledge the IOC Subcommission onBiomechanics and Physiology of Sport for selecting thisproject for the 1996 XXVI Centennial Olympic Games. Wewould like to extend a special thanks to Ben Johnson (GeorgiaState University) for all his help, support and hospitalitythroughout this project. Special thanks to CaliforniaPolytechnic State University (San Luis Obispo) studentsDavid M. Gabriel, Matthew Sanders, Jill McCart, NateTuþ anelli, Lonnie Stanton and Marcelino Martinez Jr. fortheir eþ orts in manually digitizing the data, and a specialthanks to E. David Osinski, American Baseball Foundation,for providing information concerning International Baseball.

References

Barrentine, S.W., Matsuo, T., Escamilla, R.F., Fleisig, G.S.and Andrews, J.R. (1998). Kinematic analysis of the wristand forearm during baseball pitching. Journal of Applied

Biomechanics, 14, 24± 39.Bartlett, R.M. and Best, R.J. (1988). The biomechanics of

javelin throwing: A review. Journal of Sports Sciences, 6, 1± 38.Best, R.J., Bartlett, R.M. and Morriss, C.J. (1993). A three-

dimensional analysis of javelin throwing technique. Journal

of Sports Sciences, 11, 315± 328.Bosco, C., Tarkka, I. and Komi, P.V. (1982). Eþ ect of elastic

energy and myoelectrical potentiation of triceps suraeduring stretch± shortening cycle exercise. InternationalJournal of Sports Medicine, 3, 137± 140.

Bosco, C., Montanari, G., Tarkka, I., Latteri, F., Cozzi, M.,Iachelli, G., Faina, M., Colli, R., Dal Monte, A. and LaRosa, M. (1987). The eþ ect of pre-stretch on mechanicaleý ciency of human skeletal muscle. Acta Physiologica

Scandinavica, 131, 323± 329.Clark, B. (2000). Seventh annual charts show improvement

in world pitching speeds. International Baseball Rundown,9, 4± 5.

Dietz, V., Schmidtbleicher, D. and Noth, J. (1979). Neuronalmechanisms of human locomotion. Journal of Neuro-

physiology, 42, 1212± 1222.Dillman, C.J., Fleisig, G.S. and Andrews, J.R. (1993). Bio-

mechanics of pitching with emphasis upon shoulderkinematics. Journal of Orthopaedics and Sports Physical

Therapy, 18, 402± 408.Elliott, B., Grove, J.R., Gibson, B. and Thurston, B. (1986). A

three-dimensional cinematographic analysis of the fastballand curveball pitches in baseball. International Journal of

Sport Biomechanics, 2, 20± 28.Escamilla, R.F., Fleisig, G.S., Barrentine, S.W., Zheng, N.

and Andrews, J.R. (1998). Kinematic comparisons ofthrowing diþ erent types of baseball pitches. Journal of

Applied Biomechanics, 14, 1± 23.Feltner, M.E. (1989). Three-dimensional interactions in a

two-segment kinetic chain. II: Application to the throwingarm in baseball pitching. International Journal of Sport

Biomechanics, 5, 420± 450.Feltner, M.E. and Dapena, J. (1986). Dynamics of the

shoulder and elbow joints of the throwing arm during abaseball pitch. International Journal of Sport Biomechanics,2, 235± 259.

Fleisig, G.S., Escamilla, R.F., Andrews, J.R., Matsuo, T.,Satterwhite, Y. and Barrentine, S.W. (1996). Kinematic andkinetic comparison between baseball pitching and footballpassing. Journal of Applied Biomechanics, 12, 207± 224.

Fleisig, G.S., Barrentine, S.W., Zheng, N., Escamilla, R.F. andAndrews, J.R. (1999). Kinematic and kinetic comparison ofbaseball pitching among various levels of development.Journal of Biomechanics, 32, 1371± 1375.

Gowan, I.D., Jobe, F.W., Tibone, J.E., Perry, J. and Moynes,D.R. (1987). A comparative electromyographic analysisof the shoulder during pitching: Professional versusamateur pitchers. American Journal of Sports Medicine, 15,586± 590.

Han, T.R., Kim, S.K., Yoo, M.J., Chung, S.G., Lee, S.U.and Lee, S.J. (1996). Kinematic analysis of throwing motionof Korean professional baseball pitchers. Korean Journal ofSports Medicine, 14, 13± 21.

Jobe, F.W., Tibone, J.E., Perry, J. and Moynes, D. (1983). AnEMG analysis of the shoulder in throwing and pitching:A preliminary report. American Journal of Sports Medicine,11, 3± 5.

Jobe, F.W., Moynes, D.R., Tibone, J.E. and Perry, J. (1984).An EMG analysis of the shoulder in pitching: A secondreport. American Journal of Sports Medicine, 12, 218± 220.

Komi, P.V. and Bosco, C. (1978). Utilization of stored elasticenergy in leg extensor muscles by men and women. Medicine

and Science in Sports and Exercise, 10, 261± 265.Mero, A., Komi, P.V., Korjus, T., Navarro, E. and Gregor, R.J.

(1994). Body segment contributions to javelin throwingduring ® nal thrust phases. Journal of Applied Biomechanics,10, 166± 177.

Neal, R.J., Snyder, C.W. and Kroonenberg, P.M. (1991).Individual diþ erences and segment interactions in throwing.Human Movement Science, 10, 653± 676.

Osinski, E.D. (1998). International baseball overview. InInjuries in Baseball (edited by J.R. Andrews, B. Zarins andK.E. Wilk), pp. 615± 620. Philadelphia, PA: Lippincott-Raven.

Pappas, A.M., Zawacki, R.M. and McCarthy, C.F.(1985a). Rehabilitation of the pitching shoulder. AmericanJournal of Sports Medicine, 13, 223± 235.


Pappas, A.M., Zawacki, R.M. and Sullivan, T.J. (1985b).Biomechanics of baseball pitching: A preliminary report.American Journal of Sports Medicine, 13, 216± 222.

Sakurai, S., Ikegami, Y., Okamoto, A., Yabe, K. and Toyoshima,S. (1993). A three-dimensional cinematographic analysisof upper limb movement during fastball and curveballbaseball pitches. Journal of Applied Biomechanics, 9, 47± 65.

Thurston, B. (1998). The ® ne art of pitching: Coach’ s per-spective. In Injuries in Baseball (edited by J.R. Andrews,B. Zarins and K.E. Wilk), pp. 589± 603. Philadelphia, PA:Lippincott-Raven.

Vaughn, R.E. (1985). Three-dimensional kinematics ofthe baseball pitch. In Biomechanics in Sports II (edited by

J. Terauds and J.N. Barham), pp. 72± 78. Del Mar, CA:Academic Publishers.

Watkins, R.G., Dennis, S., Dillin, W.H., Schnebel, B., Schnei-derman, G., Jobe, F., Farfan, H., Perry, J. and Pink, M.(1989). Dynamic EMG analysis of torque transfer in pro-fessional baseball pitchers. Spine, 14, 404± 408.

Werner, S.L., Fleisig, G.S., Dillman, C.J. and Andrews, J.R.(1993). Biomechanics of the elbow during baseballpitching. Journal of Orthopaedics and Sports Physical Therapy,17, 274± 278.

Wood, G.A. and Marshall, R.N. (1986). The accuracy ofDLT extrapolation in three-dimensional ® lm analysis.Journal of Biomechanics, 19, 781± 785.


kinematic comparisons of 1996 olympic baseball pitchers

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