Energy storing property of so-called energy-storing prosthetic feet.

The purpose of this study is to evaluate the energy storing and releasing property of 14 different prosthetic feet, in which so-called energy storing prosthetic feet are included. The prostheses were fitted to a young male amputee who walked on a level and slope walkway. Gait-analysis data were obtained by an automatic gait measurement system from which the ankle moment and ankle angular velocity were calculated. From these values, the power and the energy at the ankle joint were calculated. The prosthetic feet were ranked according to the total amount of energy, that is the sum of energy being stored and released. Both of the stored and released energy are important feature of the prosthetic feet. According to these evaluation criteria, we ranked the feet into three groups. The high total energy feet were Flex-Walk,a SAFE II,b and High Functionc. The medium total energy feet were SAFE,b Greissinger,d Seattle,e Copy II,f and Dynamic.d The low total energy feet were Seattle Light,e Fore Joint,g Quantum,h SACH,dSTEN,i and Uniaxial.d As for the subjective feeling, our subject preferred higher energy absorbing feet, in which a somewhat high level of energy was stored but low level of energy was released.