Propulsive force generation is critical to walking speed. Trialing limb angle and ankle moment are major contributors to increases in propulsive force during gait. For able-bodied individuals, trailing limb angle contributes twice as much as ankle moment to increases in propulsive force during speed modulation. The aim of this study was to quantify the relative contribution of ankle moment and trailing limb angle to increases in propulsive force for individuals poststroke. A biomechanical-based model previously developed for able-bodied individuals was evaluated and enhanced for individuals poststroke. Gait analysis was performed as subjects (N = 24) with chronic poststroke hemiparesis walked at their self-selected and fast walking speeds on a treadmill. Both trailing limb angle and ankle moment increased during speed modulation. In the paretic limb, the contribution from trailing limb angle versus ankle moment to increases in propulsive force is 74% and 17%. In the non-paretic limb, the contribution from trailing limb angle versus ankle moment to increases in propulsive force is 67% and 22%. Individuals poststroke increase propulsive force mainly by changing trailing limb angle in both the paretic and non-paretic limbs. This strategy may contribute to the inefficiency in poststroke walking patterns. Future work is needed to examine whether these characteristics can be modified via intervention.

Nges in muscles may minimize activity limitations and enhance participation post stroke. This article reviews the impact of aging and stroke on muscle morphology and composition, including fiber atrophy, reductions in muscle cross-sectional area, changes in muscle fiber distributions, and increases in intramuscular fat. Relationships between changes in muscle structure, muscle function, and physical mobility are reviewed. Clinical recommendations that preserve and enhance skeletal muscle in the aging adult and individuals post stroke are discussed. Future research directions that include systematic comparison of the differences in skeletal muscle between younger and older adults who have sustained a stroke are suggested....