Assessing Maximal Sprinting Speed in Highly Trained ...

TECHNICAL REPORT International Journal of Sports Physiology and Performance, 2012, 7, 76-78 © 2012 Human Kinetics, Inc.

Assessing Maximal Sprinting Speed in Highly Trained Young Soccer Players Martin Buchheit, Ben M. Simpson, Esa Peltola, and Alberto Mendez-Villanueva The aim of the present study was to locate the fastest 10-m split time (Splitbest) over a 40-m sprint in relation to age and maximal sprint speed in highly trained young soccer players. Analyses were performed on 967 independent player sprints collected in 223 highly trained young football players (Under 12 to Under 18). The maximal sprint speed was defined as the average running speed during Splitbest. The distribution of the distance associated with Splitbest was affected by age (X23 = 158.7, P < .001), with the older the players, the greater the proportion of 30-to-40-m Splitbest. There was, however, no between-group difference when data were adjusted for maximal sprint speed. Maximal sprint speed is the main determinant of the distance associated with Splitbest. Given the important disparity in Splitbest location within each age group, three (U12-U13) to two (U14-U18) 10-m intervals are still required to guarantee an accurate evaluation of maximal sprint speed in young players when using timing gates. Keywords: peak running velocity, association football, timing gates Assessing sprinting times over given distances (eg, 10-to-40-m sprint efforts) is a common practice to evaluate running speed capacities in soccer players. In addition, the estimation of maximal sprinting speed (MSS) or peak running velocity has received growing interest in past years.1–3 Its advantage is that MSS reflects a true physiological identity4 that can be (1) compared with maximal aerobic speed to draw the overall locomotor and energetic profile of each player3 and (2) used as a reference speed for match analyses using individual speed thresholds.1,2 In elite sprinters, a 60-m sprint is generally required to measure MSS,5 In (young) soccer players, however, since sprint running speed is likely to plateau after 4–5 s,2 MSS is typically obtained using a speed radar gun6 or estimated from the best (fastest) 10-m split time during a 40-m sprint using timing games.1 This latter option is cheaper but requires multiple pairs of timing gates. Knowledge of the more likely location of the fastest 10-m split time would limit the number of gates required and simplify testing procedures. The aim of the present study was therefore to locate the fastest 10-m split time (Splitbest) over a 40-m sprint in relation to age and MSS in highly trained young soccer players. Martin Buchheit, Ben M. Simpson, Esa Peltola, and Alberto Mendez-Villanueva are with the Physiology Unit, Sport Science Department, ASPIRE Academy for Sports Excellence, Doha, Qatar.

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Methods Participants Forty-meter sprint times with split times at 10 m, 20 m, and 30 m were collected over a 6 y period (three tests per year) in 223 highly trained young football players belonging to seven different age groups (Under 12 to Under 18) from the same high-level soccer academy. All the players participated on average in ∼14 h of combined soccer-specific training and competitive play per week, and had a minimum of 3 y of previous soccer-specific training.1,3 More detailed anthropometric and fitness profile of a subsample of the present players can be found elsewhere.1,3 The study was approved by the local research ethics committee and conformed to the recommendations of the Declaration of Helsinki.

Sprint Testing Players’ acceleration was defined as their first 10-m sprint time (dual-beam electronic timing gates set at 10-m intervals; Swift Performance Equipment, Lismore, Australia).1,3 Maximal sprint speed was defined as the running speed attained during Splitbest. Split times were measured to the nearest 0.01 s. Players commenced each sprint from a standing start with their front foot 0.5 m behind the first timing. The players started when ready, thus eliminating reaction time and completed two trials with the best performances retained.

Maximal Sprinting Speed in Youth Soccer  77

Statistical Analysis

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Analyses were performed on 967 independent player sprints. The average number of tests per player was 4.3 (SD: 2.8, range: 1–12). The distribution of the distance associated with Splitbest as a function of age was analyzed with the chi-square statistic. The effect of age on average Splitbest distance (ie, 10, 20, 30, and 40 m were used for 0–10, 10–20, 20–30 or 30–40 splits) was further analyzed with a one-way ANOVA. To account for differences in MSS, data were then analyzed by ANCOVA (data adjusted for individual acceleration or MSS). Bonferroni’s post hoc tests were applied when a significant interaction was found. For each AN(C)OVA, partial etasquared (η2) was calculated as measure of effect size. Values of 0.02, 0.13, and above 0.26 were considered as small, medium, and large, respectively.

Results The distribution of the distance associated with Splitbest was affected by age (X23 = 158.7, P < .001; Figure 1), with the older players showing the greater representation of 30-to-40-m Splitbest. While the distance associated with Splitbest increased with age (Table 1), there was no between-group difference when data were adjusted for MSS. Splitbest distance was significantly correlated to acceleration (r = –.40, P < .001) and MSS (r = .48, P < .001).

Discussion Our results show that the age-dependent effect on the distance associated with Splitbest is meditated by players’ MSS; that is, the faster the players, the further they reach their MSS.5 While the possible impact of age on the time needed to reach MSS was not investigated in the present study, these findings are likely related to the fact that the faster the players, the more distance they cover for a given time. In addition, players with greater acceleration achieved MSS later in the 40-m sprint compared with players with a lower acceleration (acceleration was negatively associated with Splitbest distance). This suggests that the better acceleration of the older players did not allow them to reach MSS after a shorter running distance than their younger (and slowest) counterparts. The respective impact of acceleration and MSS on the distance needed to reach MSS still remains to be investigated with instantaneous running velocity analyses.2 Finally, given the important disparity in the distance associated with Splitbest within each age group (Figure 1), three (U12–U13, 10, 20, and 30 m) to two (U14–U18, 20, and 30 m) intermediate splits are still required to guarantee an accurate evaluation of all players when using timing gates over a 40-m sprint.

Figure 1 — Fastest 10-m split time distribution as a function of age in highly trained young soccer players. *Significant within-age group X23 value with P < .05, **Significant withinage group X23 value with P < .01, ***Significant within-age group X23 value with P < .001.

78  Buchheit et al.

Table 1  Sprinting performances and average distance (SE) associated with the fastest split time as a function of age group Age Group

U12 U13 U14 U15

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U16

Files (n)

10-m time (s)

59

2.02 ± 0.01a,b,c,d,e,f

188

1.98 ±

0.01b,c,d,e,f

1.90 ±

0.01c,d,e,f

1.85 ±

0.01d,e,f

173 190 142

MSS (km∙h–1)

24.2 ± 0.2b,c,d,e,f 25.0 ± 0.2

b,c,d,e,f

26.6 ±

0.2c,d,e,f

28.4 ±

0.2d,e,f

29.6 ±

0.2e,f

Distance Associated with the Fastest Split Time (m) Nonadjusted

Adjusted for Acceleration

Adjusted for MSS

29.8 ± 0.6b,c,d,e,f

31.7 ± 0.7c,d,e,f

33.2 ± 0.7

30.7 ±

0.4b,c,d,e,f

0.4c,d,e,f

33.4 ± 0.4

32.8 ±

0.4c,d,e,f

32.0 ±

33.2 ± 0.4

33.9 ± 0.4

34.6 ± 0.4

34.5 ± 0.4

34.1 ± 0.4

35.5 ± 0.4

34.7 ± 0.4

33.9 ± 0.4

1.79 ±

0.0e,f 0.0f

30.6 ± 0.2

35.9 ± 0.4

34.8 ± 0.5

33.4 ± 0.5

U17

148

1.76 ±

U18

67

1.71 ± 0.01

31.3 ± 0.2

35.7 ± 0.6

33.9 ± 0.7

32.5 ± 0.7

< 0.001

< 0.001

< 0.001

< 0.001

0.24

0.54

0.64

0.15

0.03

< 0.01

Age Effect η2

Note. MSS: maximal sprint speed.η2: partial eta-squared. a: different from U13 with P < .05, b: different from U14 with P < .05, c: different from U15 with P < .05, d: different from U16 with P < .05, e: different from U17 with P < .05, f: different from U18 with P < .05.

References 1. Buchheit M, Mendez-Villanueva A, Simpson BM, Bourdon PC. Repeated-sprint sequences during youth soccer matches. Int J Sports Med. 2010;31:709–716. 2. Duthie GM, Pyne DB, Marsh DJ, Hooper SL. Sprint patterns in rugby union players during competition. J Strength Cond Res. 2006;20:208–214. 3. Mendez-Villanueva A, Buchheit M, Kuitunen S, Poon TK, Simpson B, Peltola E. Is the relationship between sprinting and maximal aerobic speeds in young soccer players affected by maturation? Pediatr Exerc Sci. 2010;22:497– 510.

4. Bundle MW, Hoyt RW, Weyand PG. High-speed running performance: a new approach to assessment and prediction. J Appl Physiol. 2003;95:1955–1962. 5. Korhonen MT, Mero A, Suominen H. Age-related differences in 100-m sprint performance in male and female master runners. Med Sci Sports Exerc. 2003;35:1419– 1428. 6. Impellizzeri FM, Marcora SM, Castagna C, et al. Physiological and performance effects of generic versus specific aerobic training in soccer players. Int J Sports Med. 2006;27:483–492.