Better Dynamic Balance as a Predictor of Better Horizontal Hop Performance: A Cross-Sectional Study.

Background: Sports performance depends on multiple components, including strength, power, and balance. Both dynamic balance and hip muscle strength influence horizontal hop performance, but it remains unclear whether balance predicts hop performance differently across varying levels of hip strength. Purpose: The objectives of the present study were to i) investigate whether better dynamic balance was a predictor of better hop performance in Danish volunteers without musculoskeletal conditions, and ii) investigate whether this predictive association varies between groups with maximal isometric hip muscle strength below or above the sample mean in hip flexion, extension, abduction, and adduction. Study Design: Cross-Sectional Study. Methods: One hundred thirty-five healthy volunteers aged 18-50 years were recruited from the general population via personal networks, social media, and posters on various institutions and companies in Aarhus and Horsens, Denmark. Dynamic balance was assessed with the Y-Balance test measuring reach in the anterior, posteromedial, and posterolateral directions, summed to calculate a Composite Reach Distance. Horizontal forward hop performance was assessed using the Single-leg Hop for Distance test. Maximal isometric hip muscle strength of the flexors, extensors, abductors, and adductors was measured using a fixated dynamometer. All tests were performed on the right leg. A univariate linear regression model was used with regression coefficient as measure of association. To investigate differences in the slope of the linear regressions, participants were divided into groups based on whether their maximal isometric hip muscle strength was below or above the sample mean. Results: Better dynamic balance was associated with better horizontal hop performance (β = 0.59, [95% CI 0.29-0.88], p<0.001), similar associations were found for the posterior directions. This finding was consistent regardless of whether hip muscle strength was below or above the sample mean for all four directions (p>0.05). Conclusion: Individuals with better dynamic balance displayed better horizontal hop performance. These findings provide data on subjects without musculoskeletal conditions, which can be used as reference points when compared with symptomatic populations. Level of Evidence: 3b.