Joint torque and mechanical energy flow in the support legs of skilled race walkers.

This study analyzed the joint torque and the mechanical energy flow in the support legs of skilled male race walkers. Twelve race walkers were videotaped using a high-speed camera at a frame rate of 250 Hz set perpendicular to the sagittal plane of motion; their ground reaction forces were measured with two force platforms. A two-dimensional, 14-segment, linked model was used to calculate the kinetics of the support leg joints. In the initial part of the support phase, the mechanical energy flowed into the thigh and shank by the torque of the large hip extensors and knee flexors. In the middle part, the mechanical energy generated by the torque of the large plantar flexors flowed to the foot and from the foot to the shank by the ankle joint force. The mechanical energy flow by the forward joint force of the support hip was significantly related to the walking speed in the final part of the support phase. Our findings suggest that race walkers in the final part of the support phase should exert the torque of the knee extensors and hip flexors to transfer the mechanical energy more effectively to the support thigh and shank.

Mechanical energy flow in the recovery leg of elite race walkers.

The purpose of this study was to investigate the mechanical energy flow in the recovery leg and its relationship to performance descriptors of elite male race walkers in an official race. Male race walkers participating in official 20 km races were videotaped with a VTR camera (60 Hz) set perpendicular to the course. The 28 elite race walkers (race records 1:19'50"-1:33'58") were selected as subjects. A two dimensional 14-segment linked model was used to calculate biomechanical parameters from the walking motion in the early phase of the race. The walking speed was significantly related to the step length but not related to the step frequency. Large mechanical energy flows at the hip occurred from the trunk to the foot during the first half of the recovery phase and from the foot to the trunk during the second half by the joint force power. Joint force powers at the hip in the second half of the recovery phase were significantly related to the walking speed and the step length. It is suggested that large joint force power at the hip would be one of the important factors to obtain high walking speed.