THE EFFECT OF INCREASING JUMP STEPS ON THE TAKE-OFF LEG IN BOUNDING

The purpose of this study was to clarify the effect of increasing jump steps in bounding in terms of three-dimensional joint kinetics for the take-off leg. Eleven male track and field athletes performed horizontal bounding from the standing posture. Kinematic and kinetic data were recorded using a Vicon T20 system (250 Hz) and force platforms (1,000 Hz). As jump steps increased, the joint kinetics characteristics are as follows: 1) ankle plantar flexion torque and knee extension torque and power increased, but hip extension torque and power did not increase; and 2) hip external torque and power (negative and positive) increased, particularly hip abduction torque and power. Therefore, in bounding initiated from the standing posture, ankle and knee joint kinetics from the sagittal plane and 3dimensional hip joint kinetics increased, particularly on hip adduction-abduction axis.