MECHANICS OF AMPUTEE JUMPING – JOINT WORK

Abstract

The purpose of this study was determine if dynamic elastic response (DER) prostheses could absorb energy in the eccentric phase of a vertical jump performed by trans-tibial amputees phase and return this energy in the propulsive phase. Further, given the active nature of the ankle, the study aimed to determine the mechanisms required at the remaining joints to compensate for the pathological ankle. Six amputee (AMP) and 10 able-bodied participants (AB) performed maximal vertical jumps on two force plates which were synchronised with a 9-camera VICON infra red system. The amputees did not jump as high as the AB participants. Only minimal negative work was recorded at the prosthetic ankle in the eccentric phase which resulted in minimal positive work at the ankle in the concentric phase. The intact side produced greater work than the affected side in the concentric phase. The amputees generally adopted a hip strategy to generate positive work. The work recorded at the knee was reduced on the intact and affected side and indicates the prosthesis influences the movement on both sides. To enable amputees to participate in activities which require jumping, prostheses need to be developed and amputees need to be taught how to adjust their biomechanics to store and release energy in the prosthesis.