The Jump Throw Proximal-to-Distal Sequence-Contribution of the Proximal Segments to the Shoulder Kinematics.

Kinematic descriptions of the handball jump throw are scarce, and the influence of proximal kinematics on peak shoulder internal rotation (IR) angular velocity during a jump throw is not well understood. Positional kinematic differences related to on-field demands also remain underexplored. This cross-sectional study analyzed jump throws (n = 41; central/back players = 20, wing/pivot players = 21) using 3D motion capture. The proximal-to-distal sequence was evaluated by comparing the timing of peak angular velocities across joints and segments (paired t tests). Peak angular velocity and joint range of motion excursion were compared between central/back and wing/pivot players (independent t test). Correlation coefficients assessed associations between proximal and distal variables, and significant variables were entered into a hierarchical regression to determine their contribution to shoulder IR angular velocity. Results revealed a proximal-to-distal sequence pattern. Central/back players demonstrated higher peak angular velocities in most segments, along with increased range of motion in the hip, pelvis, and thorax. Hip and pelvis kinematics explained 44% of the variance in peak shoulder IR angular velocity (R2 = .44, P = .001). This is the first study to highlight the substantial influence of proximal kinematics on shoulder IR angular velocity in the jump throw. Observed positional differences underscore the need for position-specific strength and power training strategies in handball.