Pairwise Comparison of Effects of Linear vs. Change of Direction Short Bout Sprint Intervals on Physical Performance of Youth Male Soccer Players.

Our study aimed to examine and compare the effects of 12-week repeated sprint intervals with change of direction and linear sprint intervals on physical performance in young soccer players. In this randomized, parallel three-group study, we included 60 male soccer players assigned to (i) a sprint interval with change of direction group (RS-CoD; n = 20); (ii) a linear sprint interval group (RS-LiN; n = 20); and (iii) a soccer group (SOC; n = 20). Physical performance included explosive power (countermovement jump [CMJ] and squat jump [SJ]), agility (T505, 93,639, 20Y), speed (sprints over 5 m, 10 m and 20 m), anaerobic capacity (the Running-Based Anaerobic Sprint Test [RAST]) and maximal oxygen uptake (VO2max). Over the 12 weeks, the RS-CoD group displayed significantly beneficial effects in the 93639 test (effect size [ES] = 0.42), compared to the RS-LiN (ES = 0.18) and SOC (ES = 0.12) groups. The RS-CoD group also had larger improvements in their SJ (ES = 0.87; RS-LiN 0.37; SOC 0.18), CMJ (ES = 0.56; RS-LiN 0.39; SOC 0.43), 20Y test (ES = 1.05; RS-LiN 0.67; SOC 0.56) and sprints at 5 m (ES = 1.18; RS-LiN 0.50; SOC 0.21) and 20 m (ES = 1.43; RS-LiN 0.71; SOC 0.25). The RS-CoD group displayed more beneficial improvements, making the CoD interval sprints effective training stimuli.