Biomechanical analysis of the development of human bipedal walking by a neuro-musculo-skeletal model.

A new computer simulation method, using a neuro-musculo-skeletal model, is used to clarify the process of acquisition of erect bipedal walking during human ontogeny. Walking was autonomously generated as a dynamic interaction called 'mutual entrainment' between the neural oscillation and the pendular movement of differently proportioned bodies. Walking patterns of humans with 8 different sets of alternative body proportions, varying from those of 8-month-old children to those of 22 years old adults, were simulated. The development of bipedal walking is characterized as the change from a forced oscillation controlled by the nervous system to the natural oscillation of pendular motion, determined by body proportions. Body proportions are the fundamental factor in the development of bipedal walking.