Balance and strength changes following in jury prevention protocol in female soccer players

PURPOSE: To quantify the affects of a multimodal injury prevention program previously shown to reduce injury incidence. METHODS: Female collegiate soccer players (n=9) completed the F-MARC 11 injury prevention program in addition to their soccer training over a duration of 6 weeks, whilst an age and training-age matched control group (n=9) completed an equivalent amount of soccer training. Pre- and post-intervention, all players were assessed for isokinetic strength of the knee flexors and extensors in both concentric and eccentric mode at speeds of 1.05, 3.14 and 5.23 rad·s-1, and dynamic posturography using sensory organisation and unilateral sway tests. Between group comparisons were made using repeated measures ANOVA, with significance accepted at p<=0.05. RESULTS: Post-intervention, the F11 group displayed a significant increase in the somatosensory and vestibular contributions to balance during the sensory organisation test. The F11 group also displayed a significant post-intervention decrease in sway velocity during a unilateral stance test, for both eyes open and eyes closed conditions. No changes were observed for the control group. There was no change in peak concentric or eccentric torque for either knee flexors or extensors post-intervention, irrespective of movement speed. There was however a significant change in the angle of peak torque for eccentric knee flexors at the slowest test speed. The control group showed no changes in isokinetic parameters. CONCLUSION: The F11 injury prevention program created a change in the relative contributions to dynamic balance, with an increase in both the somatosensory and vestibular ratios, and no change in the visual ratio. Whilst peak torque was unaffected, there was evidence of a shift in the angle of peak eccentric hamstring torque at the slowest test speed post-intervention. Injury reduction might therefore be attributed to those exercises involving dynamic single-legged balance, enhancing movement control rather than maximal strength.