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  1. E Greska1,
  2. N Cortes2,
  3. C Mincy1,
  4. J Ambegaonkar2,
  5. S Caswell2,
  6. J Onate3
  1. 1University of West Florida, Pensacola, FL, USA
  2. 2George Mason University, Manassas, VA, USA
  3. 3The Ohio State University, Columbus, OH, USA


Background Injury prevention programs (IPP) have demonstrated positive results in reducing the incidence of traumatic lower extremity (LE) injuries. However, it is not well documented how biomechanical alterations caused by IPP's contribute to improved physical performance.

Objective To evaluate the effects of an IPP on bilateral LE biomechanics during a single-leg hop task (SLH).

Design Quasi-experimental.

Setting Collegiate Soccer Players.

Participants 16 athletes (19.3±1.0 years; 1.67±0.05 m; 62.7±5.9 kg) free of any LE injuries.

Interventions A 3-D motion-capture system assessed LE biomechanics at pre- and post-IPP, while participants performed 3 SLH (cm) bilaterally from a force-plate. A 10-week IPP, which included agility and plyometric drills, was integrated into the normal team practice during the off-season period.

Main outcome measurements Mean peak knee flexion (KF) and abduction (KA) were appraised during propulsion phase (PP), takeoff, touchdown, and landing phase (LP). Peak ground reaction forces (GRF), normalized to body weight, were also measured during PP. Repeated measures ANOVAs assessed the effects of training and leg dominance.

Results Pre-IPP, SLH displacement significantly differed between legs (P=.013), and post-IPP, training significantly improved for both legs (P=.026), resulting in a significant interaction effect (P=.035). KF significantly decreased pre-to-post-IPP at PP for training (P=.017) and dominance (P=.015). KA significantly differed pre-to-post-IPP during PP for training (P=.025) and dominance (P=.026), takeoff for training (p=0.016), touchdown for training (P=.001), and LP for training (P=.002). Pre-to-post-IPP, training significantly increased GRF anteriorly (P=.001).

Conclusions Previous researchers have suggested increased LE injury risk due to inter-limb differences. Our results demonstrated inter-limb equivalence in SLH force-production and displacement post-IPP, with KA shifting toward a more neutral frontal-plane alignment. Thus, the increased ability and frontal-plane neutrality exhibited between legs may be an influencing factor in how the IPP can reduce LE injury risk.

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