Patterns of change in propulsion force and late braking force in patients with stroke walking at fast speeds

Abstract Increased propulsion force (PF) in the paretic limb correlates with enhanced walking speed among stroke patients. However, investigations into changes in late braking force (LBF), occurring typically during the late stance phase, remain scarce. Our objective was to elucidate the dynamics of PF and LBF alterations during fast walking in stroke patients and to discern strategies based on the shifting patterns of LBF. We retrospectively analyzed data from 100 stroke patients walking at both comfortable and fast speeds using a 3D motion analyzer. Notably, all patients exhibited augmented PF during fast walking compared to their comfortable pace. However, LBF displayed both decreasing and increasing trends. In contrast to the decreased LBF pattern, the augmented LBF pattern not only resulted in a smaller increase in PF but also entailed an elevation in LBF due to reduced in-phase coordination of the anterior tilt of the lower leg and plantar flexion of the foot during the pre-swing phase. Consequently, a compensatory strategy involving increased pelvic hike during the swing phase was adopted. Our findings contribute novel evidence indicating that alterations in LBF patterns exacerbate abnormal gait in stroke patients navigating at high speeds.