Fig. 4

Relation between reduction in energy cost and change in ankle power and knee moment, respectively, for most efficient AFO versus shoe only (left panels) and most efficient AFO versus least efficient AFO (right panels). Kopt = most efficient AFO stiffness; Kleast = least efficient AFO stiffness. Negative delta in energy cost means an improvement. Positive delta in ankle power means an increase in ankle power. Negative delta in knee external moment means an increase in external knee extension moment