Relationship of Strength and Endurance of Hip Abductors to Functional Performance

Recent studies have identified dominance-related differences in strengh and function of the lower extremity, which may be potential risk factors of injury. The purpose of this study is to evaluate asymmetries of hip abductor strength and endurance between limbs and their relationships with functional performance. We hypothesize that the dominant leg's hip abductors will demonstrate greater strength and endurance, and that these enhancements in muscle function will result in better landing mechanics. To test our hypotheses, subjects will perform a functional landing task followed by an isometric hip abductor strength test. Functional performance will be quantified by measuring the peak, and time to peak joint angular displacements of the hip and knee during the landing phase. Endurance will be evaluated using EMG in conjunction with an isometric fatigue protocol. Landing mechanics will be reevaluated following the fatigue protocol. Multiple repeated measures ANOYAs will be used to assess limb asymmetries in strenb>thand endurance, as well as and pre- and post-fatigue landing mechanics. Pearson Product Moment correlations will be used to assess the following relationships: I) hip abductor strength and pre-fatigue functional performance, and 2) hip abductor endurance and the landing mechanics of the post-fatigue functional tasks. The results of this study can be used clinically to improve pre-participation screening and the construction of return-to-play guidelines by highlighting the importance of hip abductor strength and endurance.