Lower limb joint moments on the fast belt contribute to a reduction of step length asymmetry over ground after split-belt treadmill training in stroke: A pilot study

ABSTRACT

The main goal was to investigate changes in muscle activity and joint moments related to step length (SL) symmetry improvements in individuals poststroke following repeated split-belt treadmill (SBT) walking. Twelve individuals with a first unilateral cerebral stroke presenting initial SL asymmetry (ratio = 1.10–2.05), and mean time post stroke 23 (SD 24.7 months) were included. Participants were trained during six sessions of SBT walking using an error-augmentation protocol. The training resulted in a reduction in SL asymmetry during walking over ground retained over 1-month post-training (p = 0.002). Significant increases in SL and joint moments (plantarflexors: 20–60%, knee flexors: 20–60% and hip extensors: 0–20% of the gait cycle) were observed on the side trained on the fast belt (effect size from 0.41 to 0.60). The improvement in SL symmetry was observed with an increase in plantarflexion joint moment symmetry. Changes in muscle activity varied among participants. In contrast to previous findings with a single exposure to SBT-training, our results showed no negative effects on paretic plantarflexors when walking over ground after repeated exposure to SBT walking. These findings justify larger trials to gain more solid information on the current protocol which appears as an efficient training for long-term recovery on SL asymmetry and on affected plantarflexors.

KEYWORDS:

• Stroke
• symmetry
• training
• muscle activity and joint biomechanics

Acknowledgments

We would like to acknowledge the individuals who participated in our study, the physiotherapist and the research coordinators of the Constance-Lethbridge Rehabilitation Center for their important contribution, the summer student for her help during data collection and analysis and the engineers from the Pathokinesiology Laboratory for their technical support. This work was supported by the “Réseau provincial de recherche en adaptation-réadaptation (REPAR)”. The equipment and material required for the research conducted at the Pathokinesiology Laboratory was financed by the Canada Foundation for Innovation (CFI). Martina Betschart received funding through a PhD scholarship from the Canadian Institutes of Health Research (RMF-111622) and University of Montreal (FESP).

Disclosure statement

There are no conflicts of interest to disclose.

Supplementary data

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Additional information

Funding

This work was supported by the Réseau provincial de recherche en adaptation-réadaptation (REPAR); Canada Foundation for Innovation (CFI); SensoriMotor Rehabilitation Research Team-CIHR; Faculty of graduate and Postdoctoral Studies of the University of Montreal.