A pilot study of a dynamical systems approach to examining changes in static balance of adolescents

In a dynamical systems model, movement patterns are dictated by several variables, called control parameters. The goal of this pilot study was to assess whether changes on a static balance task can be described by a dynamical systems model with body inertial properties as one of the potential control parameters. Three aspects of a dynamic system were examined in relation to a 2-ft. static balance task: a relation between the changes in the balance pattern and the control parameter, a relation between the stability of the balance pattern and the stability under perturbed conditions (1-ft. balance task), and during the perturbation lack of relation between the balance pattern and the control parameters. Nine adolescent boys, 15.3 +/- 1.0 yr. old were examined twice over a 14-wk. period. During each testing session, participants' body mass, moments of inertia, and radius from the ankle to the center of mass were calculated, after which 1- and 2-ft. balance tasks were performed. Center of pressure coordinates were recorded using a Kistler force plate. The body parameters were used to calculate the natural frequency of the body to represent the control parameter. Significant relations among all three aspects of a dynamic system examined in both the lateral and anterior-posterior axes were found. This investigation was designed for exploratory purposes and limited to correlational analysis; therefore, no concrete conclusions could be drawn. The results, however, suggest a dynamical systems approach to the study of static balance patterns may be possible.