Dellal, A, Hill-Haas, S, Lago-Penas, C, and Chamari, K. Smallsided games in soccer: Amateur vs. professional players' physiological responses, physical, and technical activities J Strength Cond Res 25(9): 2371-2381, 2011-The aim of this study was to examine the relationship between the playing level in soccer (i.e., amateur vs. professional players) and the physiological impact, perceptual ...
https://www.academia.edu/12622178/Dellal_JSCR_2011_SMALL_SIDED_GAMES_IN_SOCCER_AMATEUR...