The phase and power portraits of level and stair walking

The study of human gait from a dynamical systems approach focuses on the changes in system states depicted in the phase portrait. The present work adds a geometric technique based on muscle mechanical power in order to assess three modes of human locomotion: level walking, stair ascent, and Stair descent. Using knee joint profiles as an example, a basic organizational structure is observed at the kinetic and energetic levels for all three gaits.