Reliability and validity of a new repeated agility test as a measure of anaerobic and explosive power.

Research Unit, School and University Sportive Practices and Performance, Higher Institute of Sports and Physical Education, Kef, Tunisia.
The Journal of Strength and Conditioning Research (Impact Factor: 1.86). 02/2011; 25(2):472-80. DOI: 10.1519/JSC.0b013e3182018186
Source: PubMed

ABSTRACT The aim of this study was to evaluate the reliability and validity of a repeated modified agility test (RMAT) to assess anaerobic power and explosiveness. Twenty-seven subjects (age: 20.2 ± 0.9 years, body mass: 66.1 ± 6.0 kg, height: 176 ± 6 cm, and body fat: 11.4 ± 2.6%) participated in this study. After familiarization, subjects completed the RMAT consisting of 10 × 20-m maximal running performances (moving in forward, lateral, and backward) with ~25-second recovery between each run. Ten subjects performed the RMAT twice separated by at least 48 hours to evaluate relative and absolute reliability and usefulness of the test. The criterion validity of the RMAT was determined by examining the relationship between RMAT indices and the Wingate anaerobic test (WAT) performances and both vertical and horizontal jumps. Reliability of the total time (TT) and peak time (PT) of the RMAT was very good, with intraclass correlation coefficient > 0.90 and SEM < 5% and low bias. The usefulness of TT and PT of the RMAT was rated as "good" and "OK," respectively. The TT of the RMAT had significant correlations with the WAT (peak power: r = -0.44; mean power: r = -0.72), vertical jumps (squat jump: r = -0.50; countermovement jump: r = -0.61; drop jump (DJ): r = -0.55; DJ with dominant leg: r = -0.72; DJ with nondominant leg: r = -0.53) and 5 jump test (r = -0.56). These findings suggest that the RMAT is a reliable and valid test for assessing anaerobic power and explosiveness in multisprint sport athletes. Consequently, the RMAT is an easily applied, inexpensive field test and can provide coaches and strength and conditioning professionals with relevant information concerning the choice and the efficacy of training programs.

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    ABSTRACT: INTRODUCTION Although talent identification has been a popular topic in science and soccer, there is no consensus whether future success can be predicted by physiological tests at an early age (Le Gall et al., 2010; Williams & Reilly, 2000). For this reason, the purpose of the following study was to compare physiological characteristics among 14- to 17-year-old pre-selected soccer players in terms of subsequent career success. METHOD In 2001, the Austrian Football Association, the Department of Sport Science (University of Salzburg) and the IMSB (Vienna) launched a project targeting the development of talented soccer players who attended youth soccer academies throughout Austria. Since then, approximately 5,000 players ranging in age from 13 to 18 years were measured biannually in straight-line sprint (5, 10 and 20 m), 5 x 10 m line-to-line sprint (LL), hurdles agility run (AR), foot tapping (FT), counter movement jump (CMJ), drop jump (DJ), reaction test (RT), 2 kg standing medicine ball throw (MBT), sit and reach test (SR) and 20 m multi-stage endurance run (ER). 359 outfield players, ages 14 – 17, remained to be analyzed in a longitudinal design. Furthermore, these pre-selected academy players were retrospectively categorized based on whether they had been drafted into a youth national team (Under 18 to 21, n = 107) or not. The differences between Group (i.e. ‘selected’ vs. ‘non-selected’) and across Age (i.e. 14, 15, 16, 17 years) were analysed using a separate ANOVA for each variable. RESULTS The main effect for Age was significant (p < .01) for all comparisons. A significant main effect for Group was found in LL, F(1, 336) = 11.34, p < .01, p η2 = .03, (1-β) = .92, in AR, F(1, 313) = 6.72, p = .01, pη2 = .02, (1-β) = .73, in CMJ, F(1, 341) = 6.52, p = .01, pη2 = .02, (1-β) = .72, and in MBT, F(1, 340) = 16.34, p < .01, pη2 = .05, (1-β) = .98 in favour of selected players. Furthermore, a significant Group x Age interaction was observed displaying a greater increase for selected group in 5 m, F(3, 1050) = 4.77, p < .01, pη2 = .01, (1-β) = .90, in 10 m, F(3, 1050) = 5.19, p < .01, pη2 = .02, (1-β) = .93, in 20 m, F(3, 1050) = 4.75, p < .01, pη2 = .01, (1-β) = .90, and in MBT, F(3,1020) = 3.41, p = .02, pη2 = .01, (1-β) = .77. CONCLUSION Regarding talent identification, we conclude that performance in soccer specific sprint tests (LL, AR), as well as in CMJ and in MBT at a young age has a small but crucial impact on future career success of elite soccer players. Concerning talent development, selected players showed higher improvements in straight-line sprint and in MBT during 5-year-academy-delay. Further research is needed to clarify these differences in development. Le Gall F, et al. (2010). J Sci Med Sport, 13, 90-95. Williams AM, Reilly T. (2000). J Sports Sci, 18, 657-667.
    16 th Annual Congress of the European College of Sport Science (ECSS)16 th Annual Congress of the European College of Sport Science (ECSS); 01/2011
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