Top: Net ankle moments determined by inverse dynamics and AFO torque profiles for gait in TD children and children with crouch gait. A positive moment corresponds to a plantarflexor torque. Bottom, left: Leg impulse magnitude increased with crouch severity. Bottom, center: Reduction in leg impulse was strongly correlated with nondimensional speed for all AFO conditions. Bottom, right: GAS impulse was most strongly correlated with peak knee flexor moment. GAS activity in one subject with severe crouch was estimated to be near-zero during stance, and was omitted from this figure. Abbreviations: TD, typically-developing; MI, mild crouch; MO moderate crouch; SE; severe crouch; GAS, gastrocnemius muscle group.