Quantification of Temporal Parameters for Tripedalism

Bipedalism is one of the distinctive features of humans. However, humans in certain conditions use tripedalism for their locomotion. Patients who cannot bear their weight on their own legs or patients with balance disorders often use a cane. Temporal parameters have been defined for bipedalism, while they have not been defined for tripedalism. Therefore, in clinical rehabilitation, evaluation of patients’ gait using a cane is still very much a qualitative issue. In this study, we propose how we can define the temporal parameters for tripedalism. We calculated six quantitative numbers: (1) gait cycle of leg 1, (2) lag of foot strike between leg 1 and leg 2, (3) lag of foot strike between leg 1 and leg 3, (4) stance phase of leg 1, (5) stance phase of leg 2, and (6) stance phase of leg 3. With a set of these six elements, the foot strike and foot-off pattern of the three legs is uniquely determined. Because these elements are measurable quantitatively, we are able to express the tripedal gait in a quantitative manner with this number set. We call this number set “gait matrix”. The application of this gait matrix may be useful for evaluating patients’ gait using a cane in rehabilitation.