A SYNERGETIC GAIT TRANSITION MODEL FOR HYSTERETIC GAIT TRANSITIONS FROM WALKING TO RUNNING

A model for gait transitions from walking to running is proposed. The model is based on the theory of pattern formation and synergetics. Walking and running are considered as spatiotemporal patterns, while walk-to-run and run-to-walk transitions are regarded as bifurcations. Consequently, the model is cast in the form of coupled amplitude equations as known in the literature on pattern formation. It is shown that the model can reproduce hysteretic gait transitions that have been observed in experimental studies with humans walking on treadmills when locomotion speed is gradually increased and decreased. The control parameter is an appropriately rescaled velocity measure, the so-called Froude number, which is a body-scaled parameter that takes leg length into account. It is shown that the model can reproduce observed gait transitions for individuals and populations. In particular, probabilistic functions describing gait transitions on the population level can be defined that resemble the experimentally determined probabilistic function.