Organization of postural coordination patterns as a function of scaling the surface of support dynamics

The number and nature of the dynamical degrees of freedom (DFs) in postural coordination patterns was investigated as a function of practice over the continuously scaled frequency of the support surface dynamics. The modal number of dynamical DFs of the coordination pattern was reduced with practice particularly in the higher frequency conditions. The ankle-knee and knee-hip couplings were highly variable across the platform frequencies and practice. The findings show that practice and higher platform frequency both contribute to reducing the number of dynamical DFs of movement organization in compensatory postural control and that this is related to an increase in the strength of particularly the ankle and hip synergy.