Author(s): KAZUSHI, H., YUKI, F., NOBUAKI, F., Institution: CHUKYO UNIVERSITY , Country: JAPAN, Abstract-ID: 2496

INTRODUCTION:
The curved approach in high jump serves a dual purpose: generating centripetal force for lateral rotation and preparing the body for vertical lift. While the take-off step has been extensively studied, the kinetic mechanisms employed by athletes to negotiate the curve while simultaneously preparing for take-off—specifically across the final four steps—remain unclear. This study aimed to elucidate the step-specific kinetic strategies used by high jumpers to manage the trade-off between turning demands and take-off preparation.
METHODS:
Seven male collegiate and senior high jumpers performed competition-style curved and controlled straight approaches. We employed a validated split-step protocol to capture ground reaction forces and 3D kinematics (Theia3D) across the final four steps (Steps 1–4, excluding the take-off). Step-to-step geometric (e.g. instantaneous radius, lateral foot placement) and kinetic (e.g. centripetal impulses, joint moment impulses) variables were calculated and compared between conditions.
RESULTS:
The approach trajectory followed a ‘tight-to-loose’ strategy, where the turning radius significantly increased step-by-step throughout the curved phase. Kinetically, athletes generated the necessary centripetal force primarily through geometric adjustments (i.e., lateral foot placement) rather than by increasing stance-leg joint moment impulses compared to the straight run. A distinct transition occurred at the penultimate step (Step 4), characterised by a reversal of yaw moment impulse and increased stance-leg support impulses. This indicates a functional shift from turning mechanics to active braking and body reorientation for the jump.
CONCLUSION:
High jumpers utilise a non-uniform curve strategy to manage turning demands. By engaging a tighter curve initially and expanding the radius towards the end, athletes reduce the need for large centripetal forces in the final phase. This geometric efficiency allows them to execute necessary take-off preparations without relying on excessive joint kinetics. These findings suggest that coaching should focus on ‘geometric’ curve entry and the specific transition mechanics at the penultimate step rather than simply enforcing a uniform running path.