Unilateral vs. bilateral squat training for strength, sprints and agility in academy rugby players

The purpose of this study was to investigate the effects of a five-week lower limb unilateral or bilateral strength programme on measures of strength, sprinting and change of direction speed.Eighteen academy rugby players (18.1 ± 0.5 years, 97.4 ± 11.3 kg, 183.7 ± 11.3 cm) were randomly assigned to either a unilateral (UNI) or bilateral (BI) group. The UNI group squatted exclusively with the rear elevated split squat (RESS), whereas the BI group trained only with the bilateral back squat (BS). Both groups trained at a relative percentage of the respective one repetition max (1RM) twice weekly over a five-week period. Subjects were assessed at baseline and post-intervention for 1RM BS, 1RM RESS, 10 m sprint, 40 m sprint and Pro agility.There was a significant main effect of time for 1RM BS (F(1,16) = 86.5, p < 0.001), ES (0.84< Cohen d< 0.92), 1RM RESS (F(1,16) = 133.0, p < 0.001) ES (0.89< Cohen d <0.94). 40m sprint (F(1,16) = 14.4, p = 0.002) ES (0.47<Cohen d<0.67) and Pro-Agility (F(1,16) = 55.9, p < 0.001), ES (0.77<Cohen d< 0.89), but not 10m sprints (F(1,16) = 2.69, p = 0.121), ES (0.14<Cohen d <0.38). No significant interactions between group and time were observed for any of the dependant variables. This is the first study to suggest that BI and UNI training interventions may be equally efficacious in improving measures of lower body strength, 40m speed, and change of direction in academy level rugby players.