Dynamic characteristics of prosthetic feet: A comparison between modal parameters of walking, running and sprinting foot
Editors: Jaroslav Beran, Martin Bílek, Monika Hejnova and Petr Zabka
Publisher: Springer Netherlands
Current methods of evaluating the performance of Energy Storing and Returning (ESR) prosthesis are subjective and rely on VO2 consumption. Current prosthetic feet are designed for specific applications and the majority are designed for walking and moderate running. These mechanical feet have fixed mechanical and dynamic characteristics. They have to be selected to meet the requirement of the task and any use outside the domain of the task can result in extreme/severe lack of gait symmetry and loss of energy. For example, running specific foot can causes abnormal gait during waking and walking prosthesis can result in abnormal running gait. Depending on the type of foot these abnormality becomes more pro-gressive and pronounced with the relative speed. Poor gait symmetry results is excess consumption of energy, back pain or fatigue. To investigate if a multipur-pose foot can be designed to passively adapt to the walking or running condition one must first understand the different dynamics that are involved and are required from the task specific foot. Static tests have shown these feet to have non-linear stiffness, making the prediction of their dynamic response difficult. The most reli-able method to test for dynamic characteristics is drop and modal testing. A method approach has been developed as part of this research to test and compare the dynamic characteristics of 3 different types of foot (natural frequency, mode shapes and damping). This is needed to explore the differences in the responses of these feet that allows one to be used for walking, one to be used for running and one to be used for sprinting with easy.