Protective Compensatory Mechanisms and Biomechanical Load Distribution in ACL–Inhibited Netball Players: An Inverse Dynamics Analysis

Objectives: This study aims to investigate protective compensatory mechanisms and biomechanical load distribution on the lower limb joints in ACL-inhibited netball players. Design: Cross-sectional study and stratified participant sampling. Setting: Experimental lab-based. Participants: Five ACL-inhibited female netball players and a control group of 7 non-injured players of university recreational level took part in the study. Outcome measures: The participants performed 3 netball skills: cutting, and stop jump, and vertical jump. A Bertec force platform (960 Hz), a Qualisys automated motion capture system (120 Hz) and inverse dynamics analysis were used to obtain sagittal plane kinematics, ground reaction forces (GRFs), and joint kinetics at the hip, knee and ankle. Biomechanical variables measured included peak flexion, dorsiflexion, angular velocity, GRF components, loading rate, compressive and shear forces, and joint moments at the hip, knee and ankle. Results: The highest shear joint forces occurred in the cutting movement. However, the ACL-inhibited group showed the lowest shear and moments at the knee joint, whereas the non-injured group experienced the largest shear forces at the knee. Conclusions: The findings suggest the presence of protective compensatory mechanisms in ACL-inhibited players which consist of lower relative shear forces and moments at the injured knee joint.