Positioning the wheelchair close to the target surface reduces shoulder muscular demand for sitting pivot transfers

For many wheelchair users, performing transfers is essential for achieving independence with daily activities. However, transfers are particularly straining on the upper limbs and may contribute to the development of pain and overuse injuries at the shoulder. The purpose of this study was to determine the muscular demands of seven bilateral muscles acting at the shoulder and elbow during level and non-level transfers with and without a gap separating the wheelchair and target surface. Fourteen men with spinal cord injury transferred from their own wheelchair to a 1) level bench, 2) level bench with a 10 cm gap, 3) higher bench (+10 cm), 4) higher bench with a 10 cm gap, 5) lower bench (-10 cm), and 6) lower bench with a 10 cm gap in a random order. The maximum surface EMG reached during transfers was normalized to the subject's maximum EMG value reached during maximum static contractions for each muscle. Gaps required greater recruitment of the biceps and anterior deltoid muscles (p < 0.05). The increased muscle activation observed with gaps is likely due in part to increased combined shoulder flexion and abduction and glenohumeral joint strain on the anterior wall. As a result, individuals with SCI should be advised to position their wheelchair as close as possible to the surface they intend to transfer. © 2010 The authors and IOS Press. All rights reserved