LOWER EXTREMITY JOINT KINETICS DURING LANDING OF A DROP JUMP FROM DIFFERENT HEIGHTS AND LANDING SURFACES

Abstract

This study aimed to investigate the biomechanical effect of the lower extremity joints from a vertical fall of 30 cm and 60 cm to a soft mat and a stiff floor respectively. Result shows, from either height, the joint forces and peak joint moments decrease significantly, while the joint angles changes to a greater degree when landing on a soft mat and it needs more time from initial contact till the action stops. 'Each joint moment is effect of external moment and internal muscle moment together. The correct landing technique is that moments of all joints reduce simultaneously, Le. the contraction and passive extension of muscles should be controlled in sequence and magnitude. The highest muscle moment on contact landing is observed at hip joint on 'both landing conditions and the muscles of the knee and ankle joints guided by the hip muscles assist each other.