Course of gross mechanical efficiency in handrim wheelchair propulsion during rehabilitation of people with spinal cord injury: A prospective cohort study

Objective: To investigate the course of mechanical efficiency of handrim wheelchair propulsion during rehabilitation of subjects with (in)complete paraplegia and tetraplegia. Design: Subjects were tested at the start of active rehabilitation (t(1)), 3 months later (t(2)), and when discharged from inpatient rehabilitation (t(3)). They performed two 3-minute submaximal treadmill exercise blocks in a wheelchair. Setting: Eight rehabilitation centers in the Netherlands. Participants: Ninety-two people with (in)complete paraplegia and tetraplegia. Interventions: Not applicable. Main Outcome Measures: Mechanical efficiency values were calculated for each block. The course of mechanical efficiency was investigated using test occasions (t(1)-t(3)) completeness and level (paraplegia or tetraplegia) of the lesion, and power output as independent variables in a multilevel regression analysis. Results: Mechanical efficiency significantly increased between t(1) and t(2) only. After adding level and completeness of the lesion and their interactions with time to the model, block 2 showed that subjects with paraplegia had a significantly higher mechanical efficiency than subjects with tetraplegia. Subjects with tetraplegia improved more between t(1) and t(2) Differences in mechanical efficiency between subjects with paraplegia and tetraplegia could not be explained by differences in absolute and relative power output levels. Conclusions: Results showed a significant improvement in mechanical efficiency during the first 3 months of active rehabilitation. Subjects with paraplegia showed a higher mechanical efficiency than did subjects with tetraplegia, whereas the latter showed more improvement between t(1) and t(2).