Current Interests

Presently, amputees expend more metabolic energy than intact individuals during walking -- unilateral transtibial: 20-30% more; transfemoral & bilateral: 30-100% more (Collins 2008, Herbert 1994). Commonly prescribed Dynamic Elastic Response (DER) feet flex under walking loads, allowing mechanical energy to be stored in carbon fiber construction and returned later during the gait cycle.

During the preload phase of walking, just prior to push-off when negative work is typically performed about the ankle, DER feet flex and store energy in the carbon fiber toe plates. Even with this assistive mechanical design, DER feet have not been shown to reduce metabolic energy cost (ml O2/kg-m) or rate of expenditure (ml O2/kg-min) during walking compared to Solid-Ankle Cushioned Heel (SACH) feet (Torburn 1995). A better understanding of how the body utilizes elastic energy-storing components may assist in development of next-generation prostheses and orthoses.

Project members: Karl Zelik, Peter Adamczyk, Steve Collins, Art Kuo

External links: Karl's prosthesis page