This paper is an analysis of the motion of the leg and foot in the swing phase of a step. The analysis is based on the hypothesis that the behavior will be such as to minimize the amount of mechanical work done. Results of the analysis are the geometric position of the leg and the equivalent forces in the hip and knee joints as functions of time. Also included is the amount of work done as a function of cadence. Comparison is made with experimental results that are available in the literature.