Repeated-sprint and change-of-direction abilities in physically active individuals and soccer players: training and testing implications.

The relationship between repeated-sprint ability (RSA) and repeated change-of-direction (RCOD) matched on intervals and distances was investigated in this study. The discrimination abilities of the tests were also examined. Using a within-subject repeated measures design, 25 physically active individuals (ACTs), 16 college soccer players (COL), and 18 professional soccer players (PRO) performed the RSA and RCOD tests during which the fastest time (FT), average time (AT), total time (TT), and percentage decrement score (%Dec) were recorded. We concluded that RSA and RCOD tested separate motor abilities because the shared variance between them in the FT, AT, and TT was ≤50%. Both RSA and RCOD tests were reliable (intraclass correlation coefficient ranged 0.79-0.90) and valid performance assessments in terms of construct in that they discriminated between ACT and soccer players (irrespective of the soccer skill level in this study). Specifically, the FT, AT, and TT (but not %Dec) of RSA and RCOD were significantly higher in ACT as compared with that in both COL and PRO (p < 0.05). Most values of the RSA/RCOD index in COL and PRO were 0.59, which were significantly higher than those of ACT (0.53, p < 0.05). We proposed the use of the RSA/RCOD index with a target value of 0.59 to prioritize and quantify the training needs of RSA and RCOD for soccer players.