Effect of power-assistance on upper limb biomechanical and physiological variables during a 6-minute, manual wheelchair propulsion test: a randomised, cross-over study.

Abstract

Use of a power-assistance wheelchair could reduce the risk of musculoskeletal disorders (MSDs), however, a comprehensive biomechanical evaluation of these systems has not been carried out. This study aimed to evaluate and compare biomechanical UL propulsion variables, and physiological exercise-related variables during the use of a wheelchair with rear drive power assist device (RD-PAD) and a standard manual wheelchair (MW). Twenty-two adults with spinal cord injury were recruited. RD-PAD (SmartDrive system) was fitted to their own MW. An instrumented wheel was used to measure handrim forces, and gas exchange and heart rate were monitored. Participants performed repeated out and back runs for 6 min on a straight outdoor course. Distance covered was significantly greater with the RD-PAD (538 ± 104 m versus 470 ± 124 m). Peak mechanical effort during the propulsion phase was significantly lower with the RD-PAD (<i>p</i> < 0.001). Heart rate, metabolic equivalent of task (MET), tidal volume, minute volume, oxygen consumption, and peak oxygen consumption were all significantly lower with the RD-PAD (<i>p</i> < 0.001). The results showed that use of RD-PAD increased the distance covered by MW users and reduced the energy costs of propulsion. The biomechanical results indirectly suggest that RD-PAD may reduce the risk of MSD.Implications for RehabilitationUsing the SmartDrive system as propulsion assistance increases the travel autonomy.The SmartDrive system reduces the biomechanical constraints propelling the wheelchair on a slope and low slope.SmartDrive the system reduces the physiological solicitation related to the propulsion of wheelchair.