| Female collegiate soccer athletes suffer anterior cruciate ligament (ACL) injuries at a rate of 0.31 per 1000 athlete-exposures, with 67% of injuries expected to be from a non-contact mechanism. As well, previous studies have demonstrated dissimilarity in non-contact ACL injuries relative to dominant and non-dominant legs; with the non-dominant leg being the involved side in 48-67% of reported incidents. The aim of this study was to examine lower extremity neuromechanics relative to leg dominance during an unanticipated sidestep cutting task, with differing states of fatigue and training.;Twenty female collegiate soccer players performed three valid trials for both the dominant and non-dominant leg of an unanticipated sidestep cutting task. Three-dimensional kinematics and kinetics were recorded. Participants performed tasks during pre-and post-fatigue states, and partook in a injury prevention intervention, repeating the testing procedure at the cessation. To assess differences in neuromechanical parameters, for experiment I, a multivariate analyses of variance was conducted to assess the effect of leg dominance, and experiments II and III conducted repeated measures analyses of variance to assess the effects of fatigue and training (p<0.05).;For experiment I, no significant differences were found between dominant and non-dominant legs, but each leg displayed a unique time occurrence for peak electromyographic activity prior to contact. Experiment II, no differences were found for leg dominance, but fatigue demonstrated significant decreases in gluteus medius activation during pre-contact (p<0.001) and initial contact (p=0.002). At post-fatigue, there was a significant change in hip flexion at initial contact, and hip and knee flexion at peak knee adduction moment and peak stance (p<0.001). Significant increases (p<0.001) were also noted at peak stance for vertical ground reaction force and hip flexion moment. For experiment III, training produced decreases (p<0.001) in hip flexion angle throughout the stance phase, creating a more erect position. As well, fatigue induced decreases (p<0.006) in hip flexion and abduction throughout the stance phase, as well as decreasing (p<0.006) hip flexion and abduction moments during peak knee adduction moment. The experiments demonstrate that lower extremity neuromechanics, in the absence of fatigue, do not differ between legs during an unanticipated sidestep cutting task. |
