Hip and knee joint work modulate single-leg lateral jump performance despite the ankle being the primary contributor

Single-leg lateral jumps are a complex, multi-joint and multi-planar task with distinct biomechanical demands compared to vertical and forward jumps, yet they remain relatively under-researched. Their unique demands provide an opportunity to ask mechanistic questions regarding multi-joint control and assess key aspects of athletic performance, but detailed biomechanical descriptions of task performance are lacking. The purpose of this study was to quantify joint contributions to whole-body dynamics and jump distance, and to examine hip muscle recruitment during maximal-distance single-leg lateral jumps. Eighteen female athletes performed three maximal-distance single-leg lateral jumps from each limb while full-body kinematics, kinetics, and hip muscle activation were recorded. Whole-body (WB) centre-of-mass (COM) power and work were computed as the dot product of the ground reaction force and WB-COM velocity. Inverse dynamics analysis on linked segment models were used to calculate joint power and work. Work done on the WB-COM explained 68% of the variance observed in normalized jump distances across participants. Total joint power underestimated whole-body centre-of mass power by 23%. The ankle joint was the primary contributor (p < 0.001) though only hip (R² = 0.33, p = 0.01) and knee (R² = 0.55, p = 0.0004) joint work scaled with jump distance. Large variability in individuals' hip muscle recruitment strategy and relative hip joint contributions to task performance highlight limitations in relating muscle activation to joint, whole-body, and task performance at the group-level. These findings suggest quantifying segmental power flow and muscle power contributions might provide greater insight into how individuals coordinate and control multiple muscles and joints to perform single-leg lateral jumps.