Before revision:  In circle walking, unilateral amputees slow down when walking in circles of smaller radii and above-knee amputees in particular walk faster when the prosthetic leg is outside the circle. Using simple mathematical models, we show that the observed preferred walking speeds are predicted by minimal energy costwith increased costs for walking, changing speeds , and turning for amputees compared to non-amputees.
After revision:  In circle walking, unilateral amputees slow down when walking in circles of smaller radii . Using inverse optimization, we estimated the cost of changing speeds and turning such that the observed preferred walking speeds are predicted by minimal energy costwith increased costs for walking, changing speeds , and turning for amputees compared to non-amputees.