The Effect on Muscle Activity of Reaching Beyond Arm's Length on a Mobile Seat: A Pilot Study for Trunk Control Training for People After Stroke

Objective: This pilot study compared muscle activity during lateral reaching tasks between mobile and stable sitting using a novel therapy chair in people after stroke and healthy controls. Design: Observational pilot study. Setting: This study was conducted in a rehabilitation center for people after stroke and at the university's movement laboratory for healthy participants. Participants: A total of eleven people after stroke and fifteen healthy people (N=26) took part. Interventions: Lateral reaching exercises to the ipsilateral and contralateral sides were performed on a mobile and a stable seat. Main Outcome Measure: Muscular activity of the multifidus, erector spinae and external oblique was measured bilaterally. A within-subject linear mixed model was applied to analyze the effects of seat condition, task, muscle side, and group. Results: A seat condition effect was found for the multifidus and external oblique that was dependent on the muscle side and task. During ipsilateral reaching, the activity of the multifidi decreased for people after stroke on the mobile seat, while increasing for healthy participants. The erector spinae showed no condition effect. Decreased activity of the external oblique was found for both groups on the mobile seat. Conclusions: Mobile sitting influences muscular activity. However, these preliminary results should be further investigated in order to generate recommendations for rehabilitation.