The interface between biomechanics and motor control: dynamic systems theory and the functional role of movement variability

An integrative perspective provided by the link between biomechanics and motor control is developed in this chapter and the implications for biomechanical modelling and measurement and discussed in detail. Running and swimming are used to examine the measurement of variability in gait under the different environmental constraints of with and without gravitational forces (swimming is viewed as an aquatic gait). The classical biomechanical method of hierarchal modelling is outlined, and components of the functional pattern of coordination used to achieve locomotion are placed in this integrated schematic to facilitate motion analysis. In analysing the literature on running gait and overuse injuries, it is shown that variability in coordination during the interval between the initial foot contact and the neutral position of the stance phase is an important feature of normal. healthy running.