Physiological characteristics of male U.S. soccer development academy players: differences between age groups and player positions - Chandler, A.; Cintineo, H.; Arent, M.; McFadden, B.; Bozzini, B.; Walker, A.; Poyssick, A.; Mackowski, N.; Maldonado, W.; Arent, S. (The Journal of Strength and Conditioning Research, 2021)