This paper presents some of the ways we are attempting to understand why physically challenged children adopt the movement patterns they do. It focuses on the skill of walking and compares non-neurologically disabled persons with children with cerebral palsy. A multidisciplinary approach is advocated in which the tools of biomechanics, physiology, and dynamical systems theory are explored. Traditional biomechanics of children with cerebral palsy tend to be descriptive in nature. More recent methods include both traditional biomechanical and dynamical systems approaches to understand why physically challenged children adopt the gait patterns they do. The concept of self-optimization is introduced as a way to motivate the investigations. Mechanical energy conservation, minimal metabolic cost, normality, and stability are discussed as some of the potential optimality criteria. Optimality criteria measurement including several methods of analysis of stability are discussed, and preliminary results of findings in the three groups are reported.
Kenneth G. Holt and Suh Fang Jeng
Kenneth G. Holt, Suh Fang Jeng and Linda Fetters
Preferred stride frequency (PSF) of adult human walking has been shown to be predictable as the resonant frequency of a force driven harmonic oscillator (FDHO). The purpose of this study was to determine whether the PSF of 9-year-old children was predictable using the same resonance formula as that of adults. Subjects walked around a gymnasium at a rate at which they felt comfortable. Stride frequency was measured as the time for 20 strides and the stride period was calculated. The best-fit prediction based on resonance was then calculated using the overall center of mass of three segments (foot, shank, thigh) to determine the simple pendulum equivalent (SPE) length. Results indicated that a constant of 2 applied to the gravitational constant of the resonance formula, the same formulation used for adults, can be used to predict the cadence of children.