OPTIMIZATION OF WALKING IN CHILDREN

Previous work demonstrated that adults naturally adopt a walking frequ ency to optimize physiological cost, symmetry, and stability. Furtherm ore, the optimal frequency is predictable using the force-driven harmo nic oscillator (FDHO) model. However, no studies have established the developmental processes of optimization in children. Thus, the purpose s of this study were to examine the predictability of the preferred st ride frequency (PSF) and optimization features of 3- to 12-yr-old chil dren using the FDHO model. Forty-five children and nine adults were me asured for anthropometric data to calculate the predicted frequency. T hey later walked at three frequencies (PSF, PSF +25%, and PSF -25%) at a constant speed on a treadmill. The results indicated that the FDHO model was accurate in predicting the preferred frequency of children ( prediction error < 0.07 s). We identified three stages of learning in the development of optimization: an early manifestation of sensitivity to resonant frequency, the subsequent development of ability to modul ate walking frequency, and the final establishment of an adult optimiz ation form at age seven. Our findings suggest that walking development may be determined by the dynamic cooperation of physiological, neural , and musculoskeletal systems with respect to the environmental contex t.