Motor Adaptation to Weight Shifting Assistance Transfers to Overground Walking in People with Spinal Cord Injury

Abstract

Background Locomotor training has been used to improve walking function in people with incomplete spinal cord injury (iSCI), but functional gains are relatively small for some patients, which may be due to the lack of weight shifting training. Objective To determine whether applying a pelvis assistance force in the coronal plane during walking would improve weight shifting and stepping in people with iSCI. Design Repeated measures study. Setting Rehabilitation hospital. Participants Seventeen people with iSCI. Interventions A controlled assistance force was bilaterally applied to the pelvis in the medial‐lateral direction to facilitate weight shifting, which gradually increased during the course of treadmill walking. Main Outcome Measures Weight shifting, step length, margin of stability, and muscle activities of the weaker leg were used to quantify gait performance. The spatial‐temporal gait parameters during overground walking were collected pre, post, and 10 minutes after treadmill training. Results During treadmill walking, participants significantly improved weight shifting (ie, center of mass [CoM] lateral distance reduced from 0.16 ± 0.06 m to 0.12 ± 0.07 m, P = .012), and increased step length (from 0.35 ± 0.08 m to 0.37 ± 0.09 m, P = .037) on the stronger side when the force was applied, which were partially retained (ie, CoM distance was 0.14 ± 0.06, P = .019, and step length was 0.37 ± 0.09 m, P = .005) during the late postadaptation period when the force was removed. In addition, weight shifting and step length on the weaker side during overground walking also improved (support base reduced from 0.13 ± 0.06 m to 0.12 ± 0.06 m, P = .042, and step length increased from 0.48 ± 0.12 m to 0.51 ± 0.09 m, P = .045) after treadmill training. Conclusions Applying pelvis assistance during treadmill walking may facilitate weight shifting and improve step length in people with SCI, which may partially transfer to overground walking. Level of Evidence III.

Increased motor variability facilitates motor learning in weight shift toward the paretic side during walking in individuals post‐stroke

“…The retention of the enhanced muscle activation of knee extensors and ankle plantar flexors may be due to use‐dependent motor learning, known as neural or behavioral alterations induced by repeating certain movements (Diedrichsen et al., 2010). This is consistent with results from a previous study in humans with spinal cord injury (Lin et al., 2019b). These results suggest that repeated activation of targeted muscles induced by the application of the varied pelvis assistance might result in use‐dependent motor learning (Diedrichsen et al., 2010).…”

A novel balance training approach: Biomechanical study of virtual reality-based skateboarding

“…This decrease in force loading was believed to be due to the support provided by holding onto the handrail, while the increase in weight distribution was likely due to weight shifting (Clark et al, 2004;Wu et al, 2018;Kristiansen et al, 2019). Weight shifting has been found to improve balance by strengthening muscles, improving coordination, and enhancing of the body's center of mass, leading to increased stability during movement (Lin et al, 2019a;Lin et al, 2019b). Additionally, VR-skateboarding was found to have a shorter stance phase for the moving leg compared to walking.…”

Effects of selectively assisting impaired subtasks of walking in chronic stroke survivors

“…Next to improving lateral pelvis movement, weight shift assistance improved step length symmetry in a stroke survivor in LOPES II [ 10 ]. After incomplete spinal cord injury (injury level between C4 and T10), weight shift assistance with another robotic device also led to an increased step length in the weaker leg of the participants [ 21 ].…”