Five studies were included in the review: one cluster randomised controlled trial; two non-randomised cohort studies; one non-randomised crossover study; and one prospective matched cohort study. In total, 6,062 control and 4,713 intervention participants were included. PEDro scores ranged from 4 to 7: one study scored 7; one scored 5; and three scored 4 points.
All five studies reported beneficial numbers needed to treat for the intervention (range: 28 to 193) and relative risk reductions (range 48 per cent to 100 per cent). The pooled number needed to treat showed that to prevent one injury, 89 athletes would need to participate in the intervention (number needed to treat 89, 95% CI: 66 to136). The relative risk reduction in non-contact anterior cruciate ligament injury was 70 per cent (relative risk reduction of 70, 95% CI: 54 to 80).