Neuromaturation of human locomotion revealed by non-dimensional scaling.

When two fundamental gait parameters--step length and step frequency--are scaled non-dimensionally, thereby accounting for increases in a child's physical size, ontogenetic changes in the locomotor control strategy are revealed. We believe dimensionless velocity beta, the product of dimensionless step length and frequency, serves as a measure of neural development. It increases from the age of 18 months and reaches a plateau between 50 and 90 months, attaining the adult value of 0.45. Based on a study of 200 children, our findings lend support to a theory that posits a neuromaturation growth curve with the form: beta (t)=0.45 (1-e(-0.05t)) where t is the age in months and 0.05 is the growth coefficient.