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Journal of Science and Medicine in Sport 14 (2011) 130–134

Original paper

Energy expended by boys playing active video gamesKate White, Grant Schofield, Andrew E. Kilding ∗

Centre for Physical Activity and Nutrition Research, AUT University, Auckland, New Zealand

Received 10 September 2009; received in revised form 25 June 2010; accepted 18 July 2010

bstract

The purpose of this study was to: (1) determine energy expenditure (EE) during a range of active video games (AVGs) and (2) determinehether EE during AVGs is influenced by gaming experience or fitness. Twenty-six boys (11.4 ± 0.8 years) participated and performed a

ange of sedentary activities (resting, watching television and sedentary gaming), playing AVGs (Nintendo® Wii Bowling, Boxing, Tennis,nd Wii Fit Skiing and Step), walking and running including a maximal fitness test. During all activities, oxygen uptake, heart rate and EEere determined. The AVGs resulted in a significantly higher EE compared to rest (63–190%, p ≤ 0.001) and sedentary screen-time activities

56–184%, p ≤ 0.001). No significant differences in EE were found between the most active video games and walking. There was no evidenceo suggest that gaming experience or aerobic fitness influenced EE when playing AVGs. In conclusion, boys expended more energy during

ctive gaming compared to sedentary activities. Whilst EE during AVG is game-specific, AVGs are not intense enough to contribute towardshe 60 min of daily moderate-to-vigorous physical activity that is currently recommended for children.

2010 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

eywords: Metabolic rate; Health; Technology; Fitness

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. Introduction

Currently, there is concern about the increasing amountf time children spend engaged in sedentary activities, theumber of children who fail to achieve minimum dailyhysical activity guidelines (i.e. 60 min of moderate-to-igorous intensity activities every day),1,2 and the apparentncrease in obesity prevalence as a result of such sedentaryehaviour.1–3 Screen-based activities, including televisioniewing and playing computer games are among the most fre-uently observed sedentary activities that children partake3

ith children spending 2.5–4 h per day participating in suchctivities.2,4 In one survey, 41.7% of boys (5–14 years)atched more than 4 h of television over weekends and 26.6%atched more than 10 h during the week.4

The introduction of “active video games” (AVGs) intohe gaming market presents an opportunity to convert tra-itional, sedentary screen-time in to active screen-time and

∗ Corresponding author.E-mail addresses: andrew.kilding@aut.ac.nz, akilding@aut.ac.nz

A.E. Kilding).

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440-2440/$ – see front matter © 2010 Sports Medicine Australia. Published by Eloi:10.1016/j.jsams.2010.07.005

hus increase total daily energy expenditure (EE). Mod-rn AVGs utilise cameras and motion sensors to allow theamer to physically perform a variety of actions, depen-ent on the console, such as swinging a tennis racquet orunning. The EE during AVGs, such as those played onhe PlayStation®3 (PS3) EyeToy5,6 and the Nintendo® Wiiystems,5,6 has been measured. Lanningham-Foster et al.5

ompared EE during AVGs in lean vs. obese children andhowed that EE, when adjusted for body mass (BM), was notignificantly different between groups. Another study com-ared the EE of experienced and inexperienced gamers (aged1.8 ± 3.8 years), during an arcade-based dancing videoame. Results indicated that experienced gamers expended4% (p = 0.05) more energy during the game.7 To date, notudy has compared experienced vs. inexperienced youngamers using home-based EyeToy®, Nintendo® Wii Sportr Nintendo Wii Fit, consoles which require different move-ents to dance-specific consoles. The influence of gaming

xperience (frequency of use) on AVG playing intensity, dueo, for example, better skill or economy of movement, or anncreased ability to play at a higher intensity, is unknown foron-dance games. Likewise, it is not known how fitness level

sevier Ltd. All rights reserved.

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K. White et al. / Journal of Science

ay influence EE during AVGs. Thus, the purpose of thistudy was to: (1) determine EE, via indirect calorimetry, andelative exercise intensity during a selection of AVGs; and (2)etermine whether the EE of AVGs is influenced by experi-nce or fitness. Given the apparent greater use of video gamelay by boys,8 we restricted our analysis to this gender only.

. Methods

With institutional ethics approval, twenty-six boys (age:1.4 ± 0.8 years; BM: 41.9 ± 9.2 kg; stature: 146.4 ± 6.9 cm)rom two local schools participated. Written informed con-ent and assent was provided from parents/guardians andarticipants, respectively. Participants were divided into threeroups, ‘non-users’ (NU), ‘non-frequent users’ (NF) or ‘fre-uent users’ (FU), based on their prior Wii Sports/Fit gamingxperience obtained from a pre-study questionnaire. Specif-cally, FU were classified as having played Wii Sports/Fitames once a week or more; NF were those who had spentt least 5 h playing Wii Sports/Fit games, but did not play onregular basis (i.e. <once per week); and NU were classifieds those who had never played Wii Sports/Fit games prior tohe study.

All participants attended three testing sessions on separateays. During session one, stature, BM, resting metabolic rateRMR) and resting heart rate (HR) were measured. Partic-pants then completed a short bout of walking and runningollowed by a maximal, 20-m shuttle run test (SRT) to assessardiovascular fitness. The session concluded with a 20-mineriod of familiarisation with the AVGs to be played duringubsequent sessions. During sessions two and three, RMRas measured at the beginning of each session. Thereafter,ne sedentary activity (watching television or playing PS3)nd 2–3 AVGs were randomly chosen for participants tolay. Sedentary activities always preceded AVGs to ensurehat games did not commence with individuals in an ele-ated physiological state. Participants were given 5-min restsetween all activities. To avoid any potential affect of dietn resting metabolic rate, participants, with assistance fromarents, were requested to repeat the foods consumed duringhe 24-h preceding their first visit for each subsequent visit.

food diary was completed by each child and checked foronsistency.

Resting metabolic rate and energy expenditure of activ-ties. A valid and reliable9,10 breath-by-breath calorimetryevice (MetaMax 3B, Cortex Biophysik, Leipzig, Germany)as used to determine RMR and EE for all activities. Prior to

esting, gas and volume sensors were calibrated in accordanceith the manufacturer’s instructions. The EE for all activi-

ies was calculated from VO2 data, using the constants ofl O2 = 4.9 kcal and 1 J = 0.000239 kcal11 and was expressed

oth in absolute and relative (as a ratio of BM) terms.etabolic equivalents (METs) were calculated by dividing

he VO2 measured during each of the activities by measuredesting VO2.

mcmm

dicine in Sport 14 (2011) 130–134 131

For RMR, participants lay in a supine position for 15 minuring which a physiological resting state was achieved.12

articipants were encouraged to relax, but not sleep, and toove as little as possible. The final 5 min of data was used to

etermine RMR. The day-to-day CV for RMR was 2.1%.Screen-based activities. All screen-based activities were

arried out in a temperature controlled room (20–22 ◦C, 60%umidity). A 10-min, children-rated DVD (SpongeGuardn Duty, Nickelodeon, Australia) was chosen for partici-ants to watch. The sedentary video game (Need for SpeedroStreet, Electronic Arts, Australia) was played on a PS3onsole (PlayStation®, Sony Computer Entertainment, Newealand). Five different AVGs (Boxing, Tennis and Bowling;ii Sports, Nintendo®, Australia; and Basic Step Aerobics

nd Ski, Wii Fit, Nintendo®, Australia) were played for ainimum of 8 min against the computer. If after 8 min theyere in the middle of a game (some children progresseduicker through the games than others) we permitted themo continue until a suitable time was found to stop. This wasithin 10 min. Data collected after 8 min was not used in

ny analysis. For Wii Sports and Fit games, the single-userrial mode of each game was chosen. The order in whichVGs were played was randomised. For each AVG, meanalues for HR, EE and VO2, from the 5th to 8th minutesere determined.Walking and running. The walking and running activi-

ies were performed in a cool, air-conditioned indoor facility.hildren were instructed to walk around a 50-m circuit formin at the pace that they would typically walk to school.ollowing a 3-min rest, participants were instructed to runround the same 50-m circuit, for 3 min, at a pace that theyould maintain for this duration. We chose 3 min as the exer-ise duration because in this time frame a steady-state woulde expected.13 The mean VO2 and HR in the final 30 s ofach task were used for data analysis.

Aerobic fitness. The SRT, a widely-used valid andeliable predictor of aerobic fitness in children,14–16

as performed individually in an indoor facility. Prioro the SRT, a verbal explanation of the test wasiven to each participant. A HR monitor (Polar S810,empele, Finland) was used to determine peak HR

HRpeak). Peak oxygen consumption (VO2peak) was pre-icted from the SRT using a validated equation,15,16 where:= 31.025 + 3.238x − 3.248a + 0.1536ax. Where y = VO2peak

ml kg−1 min−1), x = maximal speed reached (km h−1) and= age (years).

Statistical analysis. The assumption of normal distribu-ion was tested using the Kolmogorov–Smirnov test (SPSSersion 14.0). Data for VO2, HR and EE (J kg−1 min−1) werenalysed using a repeated measures ANOVA and paired-amples t-tests were performed post hoc to locate significantifferences. An adjustment of the alpha level (p ≤ 0.002) was

ade using the Bonferroni correction method. An analysis of

ovariance was used, with weight as the covariate, to deter-ine differences in EE (J min).17 A mixed-model repeatedeasure ANOVA was used to determine the influence of

1 and Medicine in Sport 14 (2011) 130–134

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32 K. White et al. / Journal of Science

xperience and fitness on EE. The alpha level was set at≤ 0.05.

. Results

The peak aerobic speed from the SRT was.9 ± 0.9 km h−1. The predicted VO2peak was3.5 ± 4.8 ml kg−1 min−1 and the measured HRpeakas 200 ± 9.1 b min−1.The mean VO2, HR, EE and MET data for each activity

re presented in Table 1. When using BM as a covariate, EEid not increase significantly from rest when watching tele-ision or playing PS3. However, EE increased significantly289–768 J kg min−1) from RMR during all other activitiesTable 1). Skiing was the least active with only a 63%230 ± 90 J kg−1 min−1; p = 0.013) increase in EE above rest.he AVG yielding the greatest increase (190%; p ≤ 0.001) inE was Boxing (411 ± 100 J kg−1 min−1), followed by Step

147%; 350 ± 149 J kg−1 min−1; p ≤ 0.001). The EE duringhese two games was not significantly different to EE dur-ng walking (403 ± 97 J kg−1 min−1), but was significantlyower than EE during running (768 ± 200 J kg−1 min−1;≤ 0.001). Mean speed during walking and running was.5 ± 0.4 km h−1 and 8.7 ± 1.2 km h−1, respectively.

Percent HRpeak during AVG play ranged from 42% to2%HRpeak and %VO2peak was 27% to 48%. Comparedo rest, HR increased significantly during all activitiesp ≤ 0.001). For AVGs, the greatest increase in HR aboveest was for Boxing (77%). The smallest increase above rest35%) was for Bowling and Tennis (Table 1). No signifi-ant differences were found between HR during AVGs andalking, but HR during running was greater than all AVGs.Influence of AVG game play frequency on energy expendi-

ure. In terms of baseline characteristics of each of the groupsNU, n = 11; NF, n = 6; FU, n = 9), FU had a significantlyower BM and BMI compared to NU and NF (p ≤ 0.05). TheRT speed and predicted VO2peak was significantly lower inF compared to FU (p ≤ 0.05). Teh frequency of AVG gamelay had no effect on metabolic responses during sedentaryctivities, walking and running or any AVG.

Influence of fitness on energy expenditure. When partici-ants were ranked based on VO2peak and split into two groupslassified as low (n = 13; VO2peak < 43.0 ml kg−1 min−1)nd high fitness (n = 13; VO2peak > 43.0 ml kg−1 min−1), theow fitness group had significantly greater BM (47.4 ± 9.3s. 37.1 ± 6.2 kg; p ≤ 0.05) and BMI scores (21.9 ± 3.9s.17.4 ± 1.7; p ≤ 0.01) than the high fitness group. How-ver, no differences existed between the groups for VO2, EEr HR during sedentary and AVG activities.

. Discussion

This study found a significant increase in EE (63–190%;9–270 J kg min−1) above rest during active gaming, requir- Ta

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ng console-specific interactions, supporting the findings ofrevious similar studies.18,19 The EE during all AVGs wasignificantly higher than traditional sedentary video gamelay or television watching, although values varied betweenames and between the current and previous studies.5,6,18–20

uring Wii Skiing, Bowling and Tennis, EE increased less∼63%, 95%, and 104%, respectively) than that reportedreviously for similar games (e.g. EyeToy Groove, 123%,6

yeToy Nicktoons Movin’, 110%,5 Nintendo® Wii Bowling,34%21 and 116%18). For more active games (Wii Box-ng), EE was similar to the findings of Graf et al.,19 higherhan Graves et al.,21 but less than Maddison et al.,6 whoeported increases in EE of up to 400% from rest whenlaying Knockout Boxing, using the Eye Toy AVG console.hilst variation in sample characteristics and methodology

ould explain differences between our results and those ofrevious studies, the lower increases in EE above resting EEbserved in our study may simply reflect the slightly highereasured RMRs (Table 1) than reported previously.6,12,19,21

his aside, the relatively small increases in EE seen dur-ng some Nintendo® Wii activities may reflect the differentequirements of these activities for success. In dance games,articipants are required to keep in time with the danceoves on the screen6 and several EyeToy games require play-

rs to continuously perform activities using both their armsnd legs. Nintendo® Wii Tennis and Wii Bowling, however,equire only small movements of the wrist to “swing” theacquet and “bowl”. Continually using larger muscle groupsnd whole-body displacement is likely to be more metabol-cally demanding22 than the smaller movements required tolay some Nintendo® activities. As such, the choice of AVGnd console would appear important for physical activitynterventions using such technology.

Few studies to date have directly compared measured EEuring AVGs and compared it to measured EE during physicalctivities such as treadmill walking19 in the same subjects. Tour knowledge, no study has compared EE during AVGs andree-living activities. We adopted a common free-living tasky having subjects walk and run overground at self-selectedaces. Using such familiar activities rather than laboratory-ased tasks could be important given treadmill exercise isn unfamiliar form of exercise for children and differencesn gait between overground and treadmill running exist forhildren at fixed speeds23 which collectively could impact onE. In agreement with Graf et al.,19 EE during Wii Boxingnd Wii Step was similar to self-paced walking (Table 1).owever, EE during all AVGs was significantly less than EEuring self-paced running. This suggests that even the mostctive AVGs are still performed at a relatively low intensity≤3 METs) compared to traditional weight baring exercise.

The present study expressed intensity as a percentagef predicted VO2peak and actual HRpeak, This allows the

ntensity of AVG play to be assessed based on standard-sed exercise prescription guidelines. The most active games,

ii Step and Wii Boxing, were played at 40% and 48%f predicted VO2peak and 52% and 75% of actual HRpeak,

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dicine in Sport 14 (2011) 130–134 133

espectively. A review by Baquet et al.24 concluded that chil-ren need to participate in activities above 80% HRmax tolicit changes in VO2peak. It would therefore seem that despitencreasing physical activity, the described AVGs would note appropriate for improving cardiovascular fitness.

In the present study, physiological responses to AVGsere not altered by prior Wii Sports gaming experience ortness. In terms of experience, this is in contrast to a previoustudy7 where experienced male college-age video game play-rs had significantly higher EE than non-experienced gamers.owever, this may be due to differences in the types of gameslayed. Sell et al.7 observed that experienced dance gamelayers play more continuously than inexperienced players,ikely resulting in more ‘active’ time. Contrary to most danceames, however, several of the Wii Sports games used inhe present study are relatively self-paced (e.g. bowling andennis), and therefore players, regardless of skill or experi-nce, can stop and start without the overall outcome of theame being affected. Such ‘non-active’ time would likelyeduce the mean physiological response to the game, thoughe did not observe any evidence to suggest that beginnersrogressed through games slower than experienced players.o our knowledge, no other study has investigated the impactf fitness on AVG game play. The lack of affect would sug-est that all children can expend an equal amount of energyuring AVGs. Future research involving AVG interventionshould consider the association between fitness and AVGame play.

We acknowledge that there are some limitations with ourtudy. Firstly, our RMR values were elevated compared torevious studies.6,19 Whilst we requested subjects to visit theaboratory in a rested and fasted state this may not have beendhered to. We rule out our metabolic system as a sourcef error, since we were confident with pre- and post-testhecks and the low CV% for measures of RMR. Secondly,t is possible that the children did not give full effort dur-ng the SRT from which we obtained measures of HRpeak.his would result in an inflation of the relative HR intensity

or all activities. To address this, future studies may considerssessing children using a graded exercise test to exhaustionhilst measuring actual VO2 and HR to obtain actual phys-

cal capacities of children. Finally, we restricted our studyo a specific gender and age group. Clearly, this limits theeneralizability of the results and this should be consideredhen applying the current findings to other groups.

. Conclusion

In summary, EE during active video game play is signifi-antly higher than watching television or playing traditionalideo games and is independent of level of gaming experi-

nce and fitness in young boys. The most demanding AVGsrovided similar responses to walking and, based on inter-ational standards, should be classified as low intensityctivities. Whilst AVGs may provide children with a bet-

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34 K. White et al. / Journal of Science

er alternative to sedentary gaming, they are not a sufficienteplacement for normal physical activity, e.g. sports and out-oor play.

. Practical implications

Active video game play increases metabolic rate aboveresting levels and therefore could be used to encouragesedentary children to be more active at home.Substituting normal physical activities, such as outdoorplay and sports participation, with AVGs is not recom-mended.Future research should consider the long term effects ofAVGs on the health and fitness status of sedentary children.

cknowledgement

Thank you to Sport and Recreation New Zealand (SPARC)or assisting with funding for this study.

ppendix A. Supplementary data

Supplementary data associated with this arti-le can be found, in the online version, atoi:10.1016/j.jsams.2010.07.005.

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