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Sprint speed characteristics of high-level American female soccer players: Female Athletes in Motion (FAiM) Study
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Journal of Science and Medicine in Sport 15 (2012) 474–478
Original research
Sprint speed characteristics of high-level American female soccer players: Female Athletes in Motion (FAiM) Study Jason D. Vescovi ∗ School of Kinesiology and Health Science, York University, Canada Received 21 November 2011; received in revised form 16 February 2012; accepted 22 March 2012
Abstract Objectives: Sprint speed is important in soccer and while descriptions of male players are plentiful relatively few data exist for high-level female players. The aim of this study was to determine speed characteristics of high-level American female soccer players and evaluate if speed could distinguish between players selected (n = 56) and those not selected (n = 84) in a professional draft. Design: A cross-sectional study design. Methods: One hundred and forty women participating in a try-out for a professional soccer league had speed assessed over 35 m with splits at 5, 10 and 20 m. Speeds for the static start distances (5, 10, 20 and 35 m) as well as for ‘flying’ splits (flying 5, 10, 25 and 30 m; also first 15 and final 15 m) were determined. Results: Mean speed over 5, 10, 20 and 35 m was 15.1 ± 1.1, 18.0 ± 0.9, 21.2 ± 0.9 and 23.4 ± 0.9 km h−1 , respectively. Mean peak speed was 27.3 ± 1.4 km h−1 and occurred during the final 15 m of the sprint (20–35 m). Speed for all flying splits exceeded 21.0 km h−1 , with maximum values observed in excess of 30.0 km h−1 . All speeds, except for the flying 5 m split, were faster in the drafted players compared to non-drafted players. Conclusions: These data indicate that elite female soccer players achieve speeds ranging between 22 and 26 km h−1 over distances of 15–20 m and can reach 27 km h−1 when evaluated over 35 m. Sprint speed was able to distinguish between drafted and non-drafted players. © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Keywords: Women’s soccer; Linear sprint; Maximum speed; Draft selection
1. Introduction Soccer is considered an intermittent aerobic sport as evidenced by the ability of players to cover 10–12 km,1,2 interspersed with short sprints (2–6 s) during a 90 min match.2,3 Sprint ability is important in soccer and so the assessment of speed over 10–30 m is commonly included in test protocols.4,5 Researchers have demonstrated that speed can distinguish between elite6–8 and selected players5,6 compared to sub-elite and non-selected players. However there is a disparity in the literature with the number of studies that characterize sprint ability for male players4,6–8,9–11,12,13 exceeding the number of published reports for female
∗
Tel.: +1 703 477 4600. E-mail address: [email protected]
players5,11,14,15 and even fewer that describe American female soccer players.14,15 In addition to learning about an athlete’s speed from testing a single linear sprint, it has applications for motion analysis as demonstrated by the use of speed zones to classify various locomotor activities (i.e., walking through sprinting) during a match. Moreover, the amount of high intensity distance covered during a match has been identified as an important indicator of match performance,16 therefore accurate quantification of this parameter requires speed thresholds that accurately reflect the ability of the players being observed. Recent studies describing the physical demands of women’s soccer1,2,17 have used speed thresholds originally derived from the men’s game.18 Sprint speed varies across a wide age range for female soccer players15 and is different compared to male soccer players11 and so characterizing the speeds of high-level female soccer
1440-2440/$ – see front matter © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jsams.2012.03.006
J.D. Vescovi / Journal of Science and Medicine in Sport 15 (2012) 474–478 Table 1 Physical characteristics of elite female soccer players. All (n = 140) Age Height (cm) Body mass (kg) BMI (kg m−2 ) a
23.9 167.6 62.5 22.2
± ± ± ±
2.8 6.1 6.7 1.6
Drafted (n = 56) 22.9 167.9 63.1 22.3
± ± ± ±
2.2a 6.0 7.4 1.7
Non-drafted (n = 84) 24.6 167.3 62.1 22.1
± ± ± ±
3.0 6.3 6.3 1.6
Significantly different compared to non-drafted (p = 0.001).
players will have implications for future motion analysis studies. To date no study has reported the speed characteristics, nor identified maximum sprint speed for high-level American female soccer players. The aim of this study was to determine speed characteristics of high-level female soccer players, identify peak running speeds and evaluate if speed could distinguish between selected and non-selected players in a professional league draft. In addition percentiles and ranges of speed characteristics for this cohort of athletes were determined.
475
was broken (i.e., first movement). The best 35 m time, and all associated split times, from two trials were used for statistical analysis. A minimum of three minutes of rest was provided between trials. Speed was calculated for the static start distances (0–5 m, 0–10 m, 0–20 m and 0–35 m) as well as for the following ‘flying’ splits: flying 5 m (5–10 m), flying 10 m (10–20 m), first flying 15 m (5–20 m), final flying 15 m (20–35 m), flying 25 (10–35 m), and flying 30 (5–35 m). All sprint speeds were normally distributed. Independent t-tests were used to compare descriptive characteristics as well as to compare speed characteristics between selected and non-selected players in the subsequent professional league draft. To identify peak speed a repeated measures ANOVA was used to compare speeds determined for each split within the entire sample. Percentiles and ranges were determined and presented for the entire sample. The effect size (Cohen’s d), estimated from the ratio of the mean difference to the pooled standard deviation was also calculated. Effect size values of 0.2–0.5, 0.51–0.8, and >0.8 were considered small, moderate and large differences respectively.22 Statistical significance was accepted at p < 0.05. Data are presented as mean ± SD. All statistical procedures were performed using SPSS version 11.0.1 (SPSS Inc., Chicago, IL, USA).
2. Methods This was a cross-sectional study designed to evaluate the speed characteristics of 140 high-level American female soccer players who were invited to a try-out by the coaches of a professional women’s soccer league. The try-out was conducted in December, following the conclusion of the college soccer season. Testing occurred outdoors on a soccer field with natural turf on the first day of the four day event. Descriptive characteristics of the players are provided in Table 1. All participants had a minimum of 10 years playing experience including at the college level. The athletes were verbally informed of all experimental procedures and written informed consent was obtained prior to participation. The study was approved by the Office of Research Ethics at York University and was conducted in accordance to the Declaration of Helsinki. All of the athletes reported being free from any injury that would prevent maximal effort during testing. All athletes performed a standardized warm-up of approximately 15 min that included general exercises such as jogging, shuffling, sprinting, multi-directional movements, and dynamic stretching exercises. Participants wore shorts, t-shirt and soccer boots during testing. The assessment of linear sprints using infrared timing gates is highly reliable and does not require familiarization.19–21 Linear sprint speed was evaluated over 35 m. Infrared timing gates (Brower Timing, Utah) were positioned at the start line and at 5, 10, 20, and 35 m at a height of approximately 1.0 m. Participants stood upright, with their lead foot positioned approximately 5 cm behind the initial infrared beam (i.e., start line) and began when ready. The athletes were instructed to run at maximal speed through the final pair of sensors. Timing started when the laser of the starting gate
3. Results The sprint speeds for the entire group as well as the selected and non-selected players are displayed in Table 2. The mean speed increased over 5, 10, 20–35 m from 15.1 ± 1.1 to 18.0 ± 0.9, 21.2 ± 0.9 and 23.4 ± 0.9 km h−1 , respectively for the entire group. The mean flying split speeds ranged from 22.5 ± 1.0 km h−1 (flying 5 m) to 27.3 ± 1.4 km h−1 (final flying 15 m). Speed for each flying split were different from one another except for the flying 10 m and flying 30 m (25.9 ± 1.1 km h−1 ; p < 0.001). All of the speeds, except for flying 5 m, were greater for the selected players compared to the non-selected players (p < 0.02). Table 3 shows the ranges and percentiles for each sprint split for the entire sample (n = 140). All speed values for 5 m and 10 m were ≤20.0 km h−1 , while the maximum speed achieved over 35 m was 25.8 km h−1 . Sprint speeds for all of the flying splits were >20.0 km h−1 ; the maximum values ranged between 24.7 km h−1 (flying 5 m) and 31.2 km h−1 (final flying 15 m).
4. Discussion To the author’s knowledge this is the first study to report speed characteristics for a large cohort of high-level American female soccer players. The current data supports and expands upon previous findings that indicate speeds achieved by college-aged female soccer players during a 36.6 m sprint range between 22 and 25 km h−1 .15 Using draft selection as an indicator of playing status, the current findings are also in
476
J.D. Vescovi / Journal of Science and Medicine in Sport 15 (2012) 474–478
Table 2 Speed characteristics of elite female soccer players (km h−1 ). All (n = 140) 5m 10 m 20 m 35 m Fly 5 m Fly 10 m Fly 15 m first Fly 15 m last Fly 25 m Fly 30 m a
15.1 18.0 21.2 23.4 22.5 25.9 24.6 27.3 26.7 25.9
± ± ± ± ± ± ± ± ± ±
Drafted (n = 56)
1.1 0.9 0.9 0.9 1.0 1.1 1.0 1.4 1.3 1.1
15.4 18.3 21.6 23.9 22.6 26.3 24.9 27.8 27.2 26.3
± ± ± ± ± ± ± ± ± ±
Non-drafted (n = 84)
1.0a
14.8 17.8 21.0 23.2 22.4 25.5 24.4 27.0 26.4 25.6
0.9a 0.8a 0.9a 1.0 1.1a 1.0a 1.3a 1.2a 1.1a
± ± ± ± ± ± ± ± ± ±
Cohen’s d
1.1 0.9 0.8 0.9 1.0 1.0 0.9 1.3 1.2 1.1
0.55 0.56 0.67 0.78 0.20 0.73 0.50 0.57 0.62 0.64
Significantly different compared to non-drafted (p < 0.02).
agreement with what has been reported for male soccer players, that sprint performance can distinguish between elite and non-elite players.8,9 Sprint ability increases in young women up through 15–17 years of age, reaching speeds of approximately 21–23 km h−1 over 30–36 m in this age group.15,23 For shorter distances Hoare and Warr5 reported mean sprint speeds of 14.6, 17.3 and 19.8 km h−1 over 5, 10 and 20 m, respectively, in a group of 15–19 year old girls involved in a talent identification program. Previous work from our lab demonstrated that sprint ability in female soccer players tended to plateau between 14 and 17 yrs as there was no observable increase in mean speed over 9.1–36.6 m for a group of players 18–21 yrs.15 Similarly Mujika et al.11 showed no difference on 15 m sprint scores in senior (mean age 23 yr) compared to junior (mean age 17 yr) female soccer players. The speeds reported for the current group of high-level women appear to be about 1–2 km h−1 faster compared to other published reports. The studies by Mujika et al.11 and Vescovi et al.15 have groups of female soccer players that are similar in age to the current cohort and so the greater sprint speed is not likely a reflection of continued participation in the sport. Selection bias by the coaches is a possible explanation for the faster sprint speeds observed in the current study; all of the players were invited to try-out for a professional women’s soccer league and so it would be expected that the quality of player in this select group is higher than found in a random sample of female soccer players.
Sprint speed has been shown to distinguish between various levels of male soccer players. For example, Gissis et al.6 reported mean 10 m speed was greater in a group of youth national team athletes (18.5 km h−1 ) compared to players competing in the local youth championship (16.8 km h−1 ). Similarly Vaeyens et al.9 showed that elite and sub-elite players were about 1.0–1.5 km h−1 faster over 30 m compared to non-elite players. In a group of high-level male soccer players Cometti et al.8 showed differences of about 0.5 km h−1 when comparing Division 1 and 2 professionals to amateur players over 10 m and 30 m distances, with professionals significantly faster over 10 m but not 30 m. The current findings provide evidence that sprint speed can also distinguish between selected and non-selected high-level female players, which was also demonstrated by Hoare and Warr5 in young women involved in an Australian talent identification program. Interestingly the athletes recruited by Hoare and Warr5 were restricted to non-soccer playing women 15–19 yrs of age. In contrast, the athletes in this study had participated in soccer for over a decade, were identified by coaches and specifically invited by the league to attend the try-out, demonstrating they were all high caliber players. Those players selected during the draft had greater speeds for all but one of the sprint splits compared to the non-selected players. Despite mean differences between the two groups ranging between 0.5 and 0.8 km h−1 , the effect sizes were moderate (d = 0.50–0.78) and the faster speeds equate to about 0.5–1.0 m more distance covered during a 2–4 s sprint in the selected players. The reason sprint speed was able to
Table 3 Range and percentiles of speed characteristics (km h−1 ).
5m 10 m 20 m 35 m Fly 5 m Fly 10 m Fly 15 m first Fly 15 m last Fly 25 m Fly 30 m
Minimum
10
20
30
40
50
60
70
80
90
Maximum
12.1 15.7 19.2 21.4 20.2 23.4 22.5 23.7 23.7 23.1
13.5 16.9 20.2 22.3 21.2 24.2 23.2 25.5 24.9 24.2
14.2 17.2 20.5 22.5 21.7 24.8 23.6 26.1 25.4 24.8
14.5 17.6 20.7 22.8 22.0 25.2 24.1 26.6 25.9 25.3
14.9 17.7 20.9 23.2 22.2 25.5 24.4 26.9 26.3 25.6
15.1 17.9 21.2 23.5 22.5 25.9 24.7 27.4 26.8 25.9
15.5 18.3 21.4 23.7 22.8 26.3 25.0 27.7 27.1 26.3
15.7 18.6 21.8 24.0 23.1 26.5 25.1 28.0 27.4 26.6
15.9 18.8 22.0 24.2 23.4 26.9 25.5 28.6 27.9 26.9
16.4 19.1 22.2 24.7 23.7 27.3 25.8 29.0 28.3 27.3
17.3 20.0 23.3 25.8 24.7 28.8 27.0 31.2 30.1 28.6
J.D. Vescovi / Journal of Science and Medicine in Sport 15 (2012) 474–478
distinguish between selected and non-selected players are unclear. One possible explanation is that the coaching staff from every team in the league was given a report that included the test scores prior to the draft, however it is unknown whether the sprint times were used in the decision making process on draft day. It is unlikely that any one particular factor was the sole determinant in player selection since the needs of the team as well as a multi-factorial profile for each athlete (e.g., technical and tactical skill) must be considered before drafting a player by a professional sport organization. Another potential reason for the faster speeds observed in the drafted athletes is the age of each group – non-selected players were about 1.5 yr older compared to selected players and could reflect the decline in sprint performance associated with age.24 To date there are few published reports that describe the motion characteristics of women’s soccer.1,2,17 Of particular interest is that the speed zones used to classify locomotor activities in these studies were originally derived from the men’s game18 with no regard for sex differences in speed.11 Interestingly the speeds reported by Bangsbo et al.18 were mean speeds for locomotor activities and not thresholds. Nevertheless, the current findings have implications for future motion analysis studies of women’s soccer games as they can be used to develop more suitable standards for which to characterize high-intensity running during matches. For example, if researchers base high-speed locomotor thresholds on the average speeds observed during short sprints (<20 m) then the range would be 15–21 km h−1 . However considering that the majority of high-intensity runs during a match are initiated while the athlete is already moving (i.e., ‘flying’ start) rather than from a stationary position then the use of speeds determined from one of the splits might be more appropriate. The data presented here indicates that 22–26 km h−1 can be achieved from flying splits less than 20 m and that speeds in excess of 27 km h−1 can be obtained from the flying splits over 20 m. Decisions about the development and implementation of speed zones for high-intensity thresholds in motion analysis studies for high-level female soccer matches could be based on the current findings. The assessment of sprint speed can be influenced by several factors, namely the type of turf (natural vs. artificial), start position (on the line vs. 1–2 m behind the line), and possibly the height of the timing gates. These factors must be taken into consideration when making comparisons to previous studies as well as future investigations.
5. Conclusions The data presented in this study can be used by sport scientists and coaches to evaluate the speed characteristics of female soccer players. Over short distances (<10 m) from a standing start players were able to achieve 15–18 km h−1 , however from a flying start the mean speeds ranged from 22.5 to 27.3 km h−1 indicating the high level sprint ability of
477
these players. To date no clear rationale has been provided for the current speed thresholds used to assess high-intensity running in motion analysis of the women’s game. The current data provides sufficient knowledge that could be used to guide future work in this particular area.
Practical implications • Linear sprint speed of high-level female soccer players can be compared to the data presented. • Maximum linear sprint speed can be determined in female soccer players using a 35 m test with various intermediate splits. • Establishing speed thresholds for motion analysis studies of women’s soccer could be based on the current findings.
Acknowledgements Thanks are extended to Todd D. Brown for his assistance with data collection and to Women’s Professional Soccer, especially Joe Cummings and Tony DiCicco, for their support. No financial support was provided for this study.
References 1. Mohr M, Krustrup P, Andersson H, et al. Match activities of elite women soccer players at different performance levels. J Strength Cond Res 2008;22:341–349. 2. Krustrup P, Mohr M, Ellingsgaard H, et al. Physical demands during an elite female soccer game: importance of training status. Med Sci Sports Exerc 2005;37:1242–1248. 3. Stolen T, Chamari K, Castagna C, et al. Physiology of soccer: an update. Sports Med 2005;35:501–536. 4. Chamari K, Hachana Y, Ahmed YB, et al. Field and laboratory testing in young elite soccer players. Brit J Sports Med 2004;38:191–196. 5. Hoare DG, Warr CR. Talent identification and women’s soccer: an Australian experience. J Sports Sci 2000;18:751–758. 6. Gissis I, Papadopoulos C, Kalapotharakos VI, et al. Strength and speed characteristics of elite, subelite, and recreational young soccer players. Res Sports Med 2006;14:205–214. 7. Reilly T, Williams AM, Nevill A, et al. A multidisciplinary approach to talent identification in soccer. J Sports Sci 2000;18:695–702. 8. Cometti G, Maffiuletti NA, Pousson M, et al. Isokinetic strength and anaerobic power of elite, subelite and amateur French soccer players. Int J Sports Med 2001;22:45–51. 9. Vaeyens R, Malina RM, Janssens M, et al. A multidisciplinary selection model for youth soccer: the Ghent Youth Soccer Project. Br J Sports Med 2006;40:928–934 [discussion 934]. 10. Gil S, Ruiz F, Irazusta A, et al. Selection of young soccer players in terms of anthropometric and physiological factors. J Sports Med Phys Fitness 2007;47:25–32. 11. Mujika I, Santisteban J, Impellizzeri FM, et al. Fitness determinants of success in men’s and women’s football. J Sports Sci 2009;27:107–114. 12. Iglesias-Gutierrez E, Garcia-Roves PM, Rodriguez C, et al. Food habits and nutritional status assessment of adolescent soccer players. A necessary and accurate approach. Can J Appl Physiol 2005;30:18–32.
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13. Davis JA, Brewer J, Atkin D. Pre-season physiological characteristics of English first and second division soccer players. J Sports Sci 1992;10:541–547. 14. Vescovi JD, Brown TD, Murray TM. Positional characteristics of physical performance in Division I college female soccer players. J Sports Med Phys Fitness 2006;46:221–226. 15. Vescovi JD, Rupf R, Brown TD, et al. Physical performance characteristics of high-level female soccer players 12–21 years of age. Scand J Med Sci Sports 2011;21:670–678. 16. Mohr M, Krustrup P, Bangsbo J. Match performance of high-standard soccer players with special reference to development of fatigue. J Sports Sci 2003;21:519–528. 17. Andersson HA, Randers MB, Heiner-Moller A, et al. Elite female soccer players perform more high-intensity running when playing in international games compared with domestic league games. J Strength Cond Res 2010;24:912–919. 18. Bangsbo J, Norregaard L, Thorso F. Activity profile of competition soccer. Can J Sport Sci 1991;16:110–116.
19. Moir G, Shastri P, Connaboy C. Intersession reliability of vertical jump height in women and men. J Strength Cond Res 2008;22: 1779–1784. 20. Moir G, Button C, Glaister M, et al. Influence of familiarization on the reliability of vertical jump and acceleration sprinting performance in physically active men. J Strength Cond Res 2004;18: 276–280. 21. Markovic G, Dizdar D, Jukic I, et al. Reliability and factorial validity of squat and countermovement jump tests. J Strength Cond Res 2004;18:551–555. 22. Vincent WJ. Statistics in kinesiology. 2nd ed. Champaign: Human Kinetics; 1999. 23. Loko J, Aule R, Sikkut T, et al. Age differences in growth and physical abilities in trained and untrained girls 10–17 years of age. Am J Hum Biol 2003;15:72–77. 24. Ransdell L, Vener J, Huberty J. Masters athletes: an analysis of running, swimming and cycling performance by age and gender. J Exerc Sci Fit 2009;7:S61–S73.
Journal of Science and Medicine in Sport 15 (2012) 474–478
Original research
Sprint speed characteristics of high-level American female soccer players: Female Athletes in Motion (FAiM) Study Jason D. Vescovi ∗ School of Kinesiology and Health Science, York University, Canada Received 21 November 2011; received in revised form 16 February 2012; accepted 22 March 2012
Abstract Objectives: Sprint speed is important in soccer and while descriptions of male players are plentiful relatively few data exist for high-level female players. The aim of this study was to determine speed characteristics of high-level American female soccer players and evaluate if speed could distinguish between players selected (n = 56) and those not selected (n = 84) in a professional draft. Design: A cross-sectional study design. Methods: One hundred and forty women participating in a try-out for a professional soccer league had speed assessed over 35 m with splits at 5, 10 and 20 m. Speeds for the static start distances (5, 10, 20 and 35 m) as well as for ‘flying’ splits (flying 5, 10, 25 and 30 m; also first 15 and final 15 m) were determined. Results: Mean speed over 5, 10, 20 and 35 m was 15.1 ± 1.1, 18.0 ± 0.9, 21.2 ± 0.9 and 23.4 ± 0.9 km h−1 , respectively. Mean peak speed was 27.3 ± 1.4 km h−1 and occurred during the final 15 m of the sprint (20–35 m). Speed for all flying splits exceeded 21.0 km h−1 , with maximum values observed in excess of 30.0 km h−1 . All speeds, except for the flying 5 m split, were faster in the drafted players compared to non-drafted players. Conclusions: These data indicate that elite female soccer players achieve speeds ranging between 22 and 26 km h−1 over distances of 15–20 m and can reach 27 km h−1 when evaluated over 35 m. Sprint speed was able to distinguish between drafted and non-drafted players. © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Keywords: Women’s soccer; Linear sprint; Maximum speed; Draft selection
1. Introduction Soccer is considered an intermittent aerobic sport as evidenced by the ability of players to cover 10–12 km,1,2 interspersed with short sprints (2–6 s) during a 90 min match.2,3 Sprint ability is important in soccer and so the assessment of speed over 10–30 m is commonly included in test protocols.4,5 Researchers have demonstrated that speed can distinguish between elite6–8 and selected players5,6 compared to sub-elite and non-selected players. However there is a disparity in the literature with the number of studies that characterize sprint ability for male players4,6–8,9–11,12,13 exceeding the number of published reports for female
∗
Tel.: +1 703 477 4600. E-mail address: [email protected]
players5,11,14,15 and even fewer that describe American female soccer players.14,15 In addition to learning about an athlete’s speed from testing a single linear sprint, it has applications for motion analysis as demonstrated by the use of speed zones to classify various locomotor activities (i.e., walking through sprinting) during a match. Moreover, the amount of high intensity distance covered during a match has been identified as an important indicator of match performance,16 therefore accurate quantification of this parameter requires speed thresholds that accurately reflect the ability of the players being observed. Recent studies describing the physical demands of women’s soccer1,2,17 have used speed thresholds originally derived from the men’s game.18 Sprint speed varies across a wide age range for female soccer players15 and is different compared to male soccer players11 and so characterizing the speeds of high-level female soccer
1440-2440/$ – see front matter © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jsams.2012.03.006
J.D. Vescovi / Journal of Science and Medicine in Sport 15 (2012) 474–478 Table 1 Physical characteristics of elite female soccer players. All (n = 140) Age Height (cm) Body mass (kg) BMI (kg m−2 ) a
23.9 167.6 62.5 22.2
± ± ± ±
2.8 6.1 6.7 1.6
Drafted (n = 56) 22.9 167.9 63.1 22.3
± ± ± ±
2.2a 6.0 7.4 1.7
Non-drafted (n = 84) 24.6 167.3 62.1 22.1
± ± ± ±
3.0 6.3 6.3 1.6
Significantly different compared to non-drafted (p = 0.001).
players will have implications for future motion analysis studies. To date no study has reported the speed characteristics, nor identified maximum sprint speed for high-level American female soccer players. The aim of this study was to determine speed characteristics of high-level female soccer players, identify peak running speeds and evaluate if speed could distinguish between selected and non-selected players in a professional league draft. In addition percentiles and ranges of speed characteristics for this cohort of athletes were determined.
475
was broken (i.e., first movement). The best 35 m time, and all associated split times, from two trials were used for statistical analysis. A minimum of three minutes of rest was provided between trials. Speed was calculated for the static start distances (0–5 m, 0–10 m, 0–20 m and 0–35 m) as well as for the following ‘flying’ splits: flying 5 m (5–10 m), flying 10 m (10–20 m), first flying 15 m (5–20 m), final flying 15 m (20–35 m), flying 25 (10–35 m), and flying 30 (5–35 m). All sprint speeds were normally distributed. Independent t-tests were used to compare descriptive characteristics as well as to compare speed characteristics between selected and non-selected players in the subsequent professional league draft. To identify peak speed a repeated measures ANOVA was used to compare speeds determined for each split within the entire sample. Percentiles and ranges were determined and presented for the entire sample. The effect size (Cohen’s d), estimated from the ratio of the mean difference to the pooled standard deviation was also calculated. Effect size values of 0.2–0.5, 0.51–0.8, and >0.8 were considered small, moderate and large differences respectively.22 Statistical significance was accepted at p < 0.05. Data are presented as mean ± SD. All statistical procedures were performed using SPSS version 11.0.1 (SPSS Inc., Chicago, IL, USA).
2. Methods This was a cross-sectional study designed to evaluate the speed characteristics of 140 high-level American female soccer players who were invited to a try-out by the coaches of a professional women’s soccer league. The try-out was conducted in December, following the conclusion of the college soccer season. Testing occurred outdoors on a soccer field with natural turf on the first day of the four day event. Descriptive characteristics of the players are provided in Table 1. All participants had a minimum of 10 years playing experience including at the college level. The athletes were verbally informed of all experimental procedures and written informed consent was obtained prior to participation. The study was approved by the Office of Research Ethics at York University and was conducted in accordance to the Declaration of Helsinki. All of the athletes reported being free from any injury that would prevent maximal effort during testing. All athletes performed a standardized warm-up of approximately 15 min that included general exercises such as jogging, shuffling, sprinting, multi-directional movements, and dynamic stretching exercises. Participants wore shorts, t-shirt and soccer boots during testing. The assessment of linear sprints using infrared timing gates is highly reliable and does not require familiarization.19–21 Linear sprint speed was evaluated over 35 m. Infrared timing gates (Brower Timing, Utah) were positioned at the start line and at 5, 10, 20, and 35 m at a height of approximately 1.0 m. Participants stood upright, with their lead foot positioned approximately 5 cm behind the initial infrared beam (i.e., start line) and began when ready. The athletes were instructed to run at maximal speed through the final pair of sensors. Timing started when the laser of the starting gate
3. Results The sprint speeds for the entire group as well as the selected and non-selected players are displayed in Table 2. The mean speed increased over 5, 10, 20–35 m from 15.1 ± 1.1 to 18.0 ± 0.9, 21.2 ± 0.9 and 23.4 ± 0.9 km h−1 , respectively for the entire group. The mean flying split speeds ranged from 22.5 ± 1.0 km h−1 (flying 5 m) to 27.3 ± 1.4 km h−1 (final flying 15 m). Speed for each flying split were different from one another except for the flying 10 m and flying 30 m (25.9 ± 1.1 km h−1 ; p < 0.001). All of the speeds, except for flying 5 m, were greater for the selected players compared to the non-selected players (p < 0.02). Table 3 shows the ranges and percentiles for each sprint split for the entire sample (n = 140). All speed values for 5 m and 10 m were ≤20.0 km h−1 , while the maximum speed achieved over 35 m was 25.8 km h−1 . Sprint speeds for all of the flying splits were >20.0 km h−1 ; the maximum values ranged between 24.7 km h−1 (flying 5 m) and 31.2 km h−1 (final flying 15 m).
4. Discussion To the author’s knowledge this is the first study to report speed characteristics for a large cohort of high-level American female soccer players. The current data supports and expands upon previous findings that indicate speeds achieved by college-aged female soccer players during a 36.6 m sprint range between 22 and 25 km h−1 .15 Using draft selection as an indicator of playing status, the current findings are also in
476
J.D. Vescovi / Journal of Science and Medicine in Sport 15 (2012) 474–478
Table 2 Speed characteristics of elite female soccer players (km h−1 ). All (n = 140) 5m 10 m 20 m 35 m Fly 5 m Fly 10 m Fly 15 m first Fly 15 m last Fly 25 m Fly 30 m a
15.1 18.0 21.2 23.4 22.5 25.9 24.6 27.3 26.7 25.9
± ± ± ± ± ± ± ± ± ±
Drafted (n = 56)
1.1 0.9 0.9 0.9 1.0 1.1 1.0 1.4 1.3 1.1
15.4 18.3 21.6 23.9 22.6 26.3 24.9 27.8 27.2 26.3
± ± ± ± ± ± ± ± ± ±
Non-drafted (n = 84)
1.0a
14.8 17.8 21.0 23.2 22.4 25.5 24.4 27.0 26.4 25.6
0.9a 0.8a 0.9a 1.0 1.1a 1.0a 1.3a 1.2a 1.1a
± ± ± ± ± ± ± ± ± ±
Cohen’s d
1.1 0.9 0.8 0.9 1.0 1.0 0.9 1.3 1.2 1.1
0.55 0.56 0.67 0.78 0.20 0.73 0.50 0.57 0.62 0.64
Significantly different compared to non-drafted (p < 0.02).
agreement with what has been reported for male soccer players, that sprint performance can distinguish between elite and non-elite players.8,9 Sprint ability increases in young women up through 15–17 years of age, reaching speeds of approximately 21–23 km h−1 over 30–36 m in this age group.15,23 For shorter distances Hoare and Warr5 reported mean sprint speeds of 14.6, 17.3 and 19.8 km h−1 over 5, 10 and 20 m, respectively, in a group of 15–19 year old girls involved in a talent identification program. Previous work from our lab demonstrated that sprint ability in female soccer players tended to plateau between 14 and 17 yrs as there was no observable increase in mean speed over 9.1–36.6 m for a group of players 18–21 yrs.15 Similarly Mujika et al.11 showed no difference on 15 m sprint scores in senior (mean age 23 yr) compared to junior (mean age 17 yr) female soccer players. The speeds reported for the current group of high-level women appear to be about 1–2 km h−1 faster compared to other published reports. The studies by Mujika et al.11 and Vescovi et al.15 have groups of female soccer players that are similar in age to the current cohort and so the greater sprint speed is not likely a reflection of continued participation in the sport. Selection bias by the coaches is a possible explanation for the faster sprint speeds observed in the current study; all of the players were invited to try-out for a professional women’s soccer league and so it would be expected that the quality of player in this select group is higher than found in a random sample of female soccer players.
Sprint speed has been shown to distinguish between various levels of male soccer players. For example, Gissis et al.6 reported mean 10 m speed was greater in a group of youth national team athletes (18.5 km h−1 ) compared to players competing in the local youth championship (16.8 km h−1 ). Similarly Vaeyens et al.9 showed that elite and sub-elite players were about 1.0–1.5 km h−1 faster over 30 m compared to non-elite players. In a group of high-level male soccer players Cometti et al.8 showed differences of about 0.5 km h−1 when comparing Division 1 and 2 professionals to amateur players over 10 m and 30 m distances, with professionals significantly faster over 10 m but not 30 m. The current findings provide evidence that sprint speed can also distinguish between selected and non-selected high-level female players, which was also demonstrated by Hoare and Warr5 in young women involved in an Australian talent identification program. Interestingly the athletes recruited by Hoare and Warr5 were restricted to non-soccer playing women 15–19 yrs of age. In contrast, the athletes in this study had participated in soccer for over a decade, were identified by coaches and specifically invited by the league to attend the try-out, demonstrating they were all high caliber players. Those players selected during the draft had greater speeds for all but one of the sprint splits compared to the non-selected players. Despite mean differences between the two groups ranging between 0.5 and 0.8 km h−1 , the effect sizes were moderate (d = 0.50–0.78) and the faster speeds equate to about 0.5–1.0 m more distance covered during a 2–4 s sprint in the selected players. The reason sprint speed was able to
Table 3 Range and percentiles of speed characteristics (km h−1 ).
5m 10 m 20 m 35 m Fly 5 m Fly 10 m Fly 15 m first Fly 15 m last Fly 25 m Fly 30 m
Minimum
10
20
30
40
50
60
70
80
90
Maximum
12.1 15.7 19.2 21.4 20.2 23.4 22.5 23.7 23.7 23.1
13.5 16.9 20.2 22.3 21.2 24.2 23.2 25.5 24.9 24.2
14.2 17.2 20.5 22.5 21.7 24.8 23.6 26.1 25.4 24.8
14.5 17.6 20.7 22.8 22.0 25.2 24.1 26.6 25.9 25.3
14.9 17.7 20.9 23.2 22.2 25.5 24.4 26.9 26.3 25.6
15.1 17.9 21.2 23.5 22.5 25.9 24.7 27.4 26.8 25.9
15.5 18.3 21.4 23.7 22.8 26.3 25.0 27.7 27.1 26.3
15.7 18.6 21.8 24.0 23.1 26.5 25.1 28.0 27.4 26.6
15.9 18.8 22.0 24.2 23.4 26.9 25.5 28.6 27.9 26.9
16.4 19.1 22.2 24.7 23.7 27.3 25.8 29.0 28.3 27.3
17.3 20.0 23.3 25.8 24.7 28.8 27.0 31.2 30.1 28.6
J.D. Vescovi / Journal of Science and Medicine in Sport 15 (2012) 474–478
distinguish between selected and non-selected players are unclear. One possible explanation is that the coaching staff from every team in the league was given a report that included the test scores prior to the draft, however it is unknown whether the sprint times were used in the decision making process on draft day. It is unlikely that any one particular factor was the sole determinant in player selection since the needs of the team as well as a multi-factorial profile for each athlete (e.g., technical and tactical skill) must be considered before drafting a player by a professional sport organization. Another potential reason for the faster speeds observed in the drafted athletes is the age of each group – non-selected players were about 1.5 yr older compared to selected players and could reflect the decline in sprint performance associated with age.24 To date there are few published reports that describe the motion characteristics of women’s soccer.1,2,17 Of particular interest is that the speed zones used to classify locomotor activities in these studies were originally derived from the men’s game18 with no regard for sex differences in speed.11 Interestingly the speeds reported by Bangsbo et al.18 were mean speeds for locomotor activities and not thresholds. Nevertheless, the current findings have implications for future motion analysis studies of women’s soccer games as they can be used to develop more suitable standards for which to characterize high-intensity running during matches. For example, if researchers base high-speed locomotor thresholds on the average speeds observed during short sprints (<20 m) then the range would be 15–21 km h−1 . However considering that the majority of high-intensity runs during a match are initiated while the athlete is already moving (i.e., ‘flying’ start) rather than from a stationary position then the use of speeds determined from one of the splits might be more appropriate. The data presented here indicates that 22–26 km h−1 can be achieved from flying splits less than 20 m and that speeds in excess of 27 km h−1 can be obtained from the flying splits over 20 m. Decisions about the development and implementation of speed zones for high-intensity thresholds in motion analysis studies for high-level female soccer matches could be based on the current findings. The assessment of sprint speed can be influenced by several factors, namely the type of turf (natural vs. artificial), start position (on the line vs. 1–2 m behind the line), and possibly the height of the timing gates. These factors must be taken into consideration when making comparisons to previous studies as well as future investigations.
5. Conclusions The data presented in this study can be used by sport scientists and coaches to evaluate the speed characteristics of female soccer players. Over short distances (<10 m) from a standing start players were able to achieve 15–18 km h−1 , however from a flying start the mean speeds ranged from 22.5 to 27.3 km h−1 indicating the high level sprint ability of
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these players. To date no clear rationale has been provided for the current speed thresholds used to assess high-intensity running in motion analysis of the women’s game. The current data provides sufficient knowledge that could be used to guide future work in this particular area.
Practical implications • Linear sprint speed of high-level female soccer players can be compared to the data presented. • Maximum linear sprint speed can be determined in female soccer players using a 35 m test with various intermediate splits. • Establishing speed thresholds for motion analysis studies of women’s soccer could be based on the current findings.
Acknowledgements Thanks are extended to Todd D. Brown for his assistance with data collection and to Women’s Professional Soccer, especially Joe Cummings and Tony DiCicco, for their support. No financial support was provided for this study.
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