The influence of lower limb kinematic characteristics in stroke patients on gait speed mediated by paretic side propulsive force.

Abstract

The relationships among gait speed, paretic side propulsive force (PPF), and kinematic characteristics in stroke patients remain unclear. This study retrospectively analyzed data from 109 post-stroke patients to identify kinematic characteristics influencing gait speed mediated by PPF. Motion capture system was used for measuring ground walking, and hip, knee, and ankle joint angle during stance phase of paretic side were extracted. The joint angle data were classified into four phases (the initial double-support (Phase 1), the first and second 50% of the single-leg stance (Phase 2, Phase 3), the second double-support (Phase 4)), and average angle of the time series for each phase was calculated (kinematic variables). Comfortable gait speed (CGS) and PPF were also averaged. Statistical analysis first performed correlation analysis between CGS, PPF and kinematic variables. Next, mediation analysis was conducted using kinematic variables as independent variables, CGS as dependent variable, and PPF as mediating variable. Correlation analysis revealed that the kinematic variables of hip and knee joints in all phases, and ankle joint in Phase 3, showed significant correlations with CGS and PPF. For mediation analysis, the mediation model with only indirect effects significant was established for the following variables: hip extension (Total Effect (TE) =  - 0.007, p = 0.018), knee flexion (TE = 0.010, p < 0.01), and ankle dorsiflexion (TE = 0.013, p < 0.01) in Phases 3 and hip extension in Phase 4 (TE =  - 0.011, p < 0.01). These four kinematic variables were each found to influence gait speed mediated by PPF. In gait intervention, focusing on these joint movements during mid-to-late stance phase is important.