Relationship between Hip Abductor Muscle Strength and Frontal Plane Kinematics: A Cross-Sectional Study in Elite Handball Athletes

Frontal plane kinematics of the lower limb could be especially relevant in the risk of injuries in handball (HB) athletes. An association between lower limb frontal plane kinematics and hip abductor muscles strength has been investigated in different populations. However, the relationship between pelvis, hip, and knee frontal plane kinematics and the hip abductor strength in HB athletes has not been considered. Therefore, the objective of this study was to evaluate the relationship between hip abductor muscles strength and frontal plane kinematics (contralateral pelvic drop, femoral adduction, and knee valgus) in elite HB athletes using 2D analysis. Design: Cross-sectional and correlational study. Methods: Thirty-four male professional HB athletes were recruited. Athletes had to perform a deep single-leg squat. The frontal plane was recorded using the Camera app on iPhone (5SE). The clinical variables were hip abductor muscles strength assessed using a Lafayette hand-held dynamometer version 01165, and frontal plane kinematics measured with Kinovea 2D software version 0.9.4. Both variables were measured independently by two different examiners. Results: The correlation analysis showed a statistically significant negative correlation between the hip abductor muscles strength and the pelvic drop angle (p < 0.001; PCC: -0.873). A statistically significant positive correlation was found between the hip abductor muscles strength and the femoral adduction angle (p < 0.001; PCC: 0.767) and between the hip abductor muscles strength and the knee valgus angle (p < 0.001; PCC: 0.855). Conclusion: Hip abductor muscles strongly correlate with frontal plane kinematics in HB athletes.