Lower limb muscle activity underlying temporal gait asymmetry post-stroke

Objective: Asymmetric walking after stroke is common, detrimental, and difficult to treat, but current knowledge of underlying physiological mechanisms is limited. This study investigated electromyographic (EMG) features of temporal gait asymmetry (TGA). Methods: Participants post-stroke with or without TGA and control adults (n=27, 8, and 9, respectively) performed self-paced overground gait trials. EMG, force plate, and motion capture data were collected. Lower limb muscle activity was compared across groups and sides (more/less affected). Results: Significant group by side interaction effects were found: more affected plantarflexor stance activity ended early (p=.0006) and less affected dorsiflexor on/off time was delayed (p<.01) in persons with asymmetry compared to symmetric and normative controls. The TGA group exhibited fewer dorsiflexor bursts during swing (p=.0009). Conclusions: Temporal patterns of muscular activation, particularly about the ankle around the stance to-swing transition period, are associated with TGA. The results may reflect specific impairments or compensations that affect locomotor coordination. Significance: Neuromuscular underpinnings of spatiotemporal asymmetry have not been previously characterized. These novel findings may inform targeted therapeutic strategies to improve gait qualityafter stroke.This work was supported by a Collaborative Health Research Projects Grant from the Canadian Institutes of Health Research and the National Science Engineering Research Council the Heart and Stroke Foundation [#337523]; Canadian Institutes of Health Research [MOP 133577]. The authors also acknowledge the support of the Toronto Rehabilitation Institute; equipment and space have been funded with grants from the Canada Foundation for Innovation, Ontario Innovation Trust, and Ministry of Research and Innovation. AM holds a New Investigator Award from the Canadian Institutes of Health Research (MSH 141983) and KP holds a salary award from the Heart and Stroke Foundation. Sponsors were not involved in study design and execution or article preparation