Relationship Between Hip Strength And Hip Mechanics During Running And Jumping In Collegiate Cross-Country Runners

Cross-country runners competing at the collegiate level are highly susceptible to lower extremity running-related injury. Reduced hip strength and altered hip mechanics have been shown to be prominent risk factors for sustaining a running-related injury. Although several studies have examined the relationship between hip strength and hip kinematics, these studies have focused on recreational runners and yielded mixed results. Thus, research on competitive collegiate cross-country runners is needed to inform training and rehabilitative strategies. PURPOSE: To determine the relationship between isometric hip strength and hip kinematics during running and jumping in competitive collegiate cross-country runners. METHODS: 16 NCAA Division I cross-country runners (11 M, 5 F; age: 20.1 ± 1.9 yrs; running experience: 7.8 ± 2.5 yrs; weekly mileage: 60.2 ± 13.9 miles) participated in this study. Peak hip abduction (ABD) and hip external rotation (ER) strength were assessed with a handheld dynamometer and normalized to leg length and body mass. 3D motion analysis during running (3.8 m/s) and single limb counter movement jumps were used to assess peak hip adduction (ADD) and hip internal rotation (IR) angle. Pearson correlation coefficients were used to assess the relationship between hip strength and hip mechanics during running and jumping. RESULTS: Peak hip ABD strength (2.1 ± 0.5 Nm/kg) was moderately significantly associated with peak hip ADD during running (r = -0.54, p = 0.03), but not single limb jumping (r = -0.23, p = 0.39). Peak hip ER strength (1.0 ± 0.2 Nm/kg) was not significantly associated with peak hip IR during running (r = 0.20, p = 0.45) or single limb jumping (r = 0.42, p = 0.11). Hip mechanics during running and single limb jumping were moderately significantly associated (ADD: r = 0.53, p = 0.04; IR: r = 0.51, p = 0.04). CONCLUSIONS: Although hip mechanics during running and single limb jumping were significantly associated, they were not consistently associated with hip strength. This indicates that factors other than hip strength, such as neuromuscular control, may be important determinants of hip kinematics. Utilization of task-specific exercises, such as single limb drills focusing on control and stability, may be needed in addition to hip strength during the training of collegiate cross-country runners.