Effects of Linear Versus Changes of Direction Repeated Sprints on Intermittent High Intensity Running Performance in High-level Junior Football Players over an Entire Season: A Randomized Trial

Background: Changes of direction (COD) repeated sprints (RSs) might have greater relevance to football than linear RSs. We aimed to compare the e ects of linear and COD RSs on intermittent high intensity running (HIR) over an entire season. Methods: In total, 19 high-level male football players (16–19 years) randomly performed linear RSs or COD RSs twice a week during their competitive season over 22 weeks. Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2), and 10- and 20-m sprint was assessed pre-, mid- (11 weeks), and post-intervention (22 weeks). Maximal oxygen uptake (VO2max) was assessed pre- and post-intervention. Results: There was no interaction e ect (time x group) in Yo-Yo IR2 (p=0.36,p 2=0.06) or sprint tests (10 m:p=0.55,p 2=0.04, 20 m:p=0.28p 2=0.08), and no change di erences between groups. There was a main e ect of time for Yo-Yo IR2 (p=0.002,p 2=0.31) but not in sprints or VO2max. Conclusion: Linear and COD RS exercise twice a week over 22 weeks equally improves intermittent HIR performance but does not improve sprint time or aerobic power in high-level junior football players. However, due to our two-armed intervention, we cannot exclude possible e ects from other exercise components in the players' exercise program.

This study compares the effects of linear and COD repeated sprints on high intensity running in junior football players.