No comprehensive biomechanical study has documented upper extremity (U/E) kinematics and kinetics during the performance of wheelchair wheelies among manual wheelchair users (MWUs). The aim of this study was to describe movement strategies (kinematics), mechanical loads (kinetics), and power at the nondominant U/E joints during a wheelie among MWUs with spinal cord injury (SCI). During a laboratory assessment, 16 MWUs with SCI completed four wheelie trials on a rigid surface. Each participant’s wheelchair was equipped with instrumented wheels to record handrim kinetics, while U/E and wheelchair kinematics were recorded with a 3D motion analysis system. The greatest mean and peak total net joint moments were generated by the shoulder flexors (mean = 7.2 ± 3.5 N·m; peak = 20.7 ± 12.9 N·m) and internal rotators (mean = 3.8 ± 2.2 N·m; peak = 11.4 ± 10.9 N·m) as well as by the elbow flexors (mean = 5.5 ± 2.5 N·m; peak = 14.1 ± 7.6 N·m) during the performance of wheelies. Shoulder flexor and internal rotator efforts predominantly generate the effort needed to lift the front wheels of the wheelchair, whereas the elbow flexor muscles control these shoulder efforts to reach a state of balance. In combination with a task-specific training program that remains essential to properly learn how to control wheelies among MWUs with SCI, rehabilitation professionals should also propose a shoulder flexor, internal rotator, and elbow flexor strengthening program.
Mathieu Lalumiere, Dany H. Gagnon, and Guillaume Desroches are with the Pathokinesiology Laboratory in the Center for Interdisciplinary Research in Rehabilitation of Greater Montréal at the Institut de réadaptation Gingras-Lindsay-de-Montréal in Montréal, QC, Canada as well as the School of Rehabilitation at the Université de Montréal in Montréal, QC, Canada. François Routhier and Laurent Bouyer are with the Center for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS) at the Institut de réadaptation en déficience physique de Québec in Québec City, QC, Canada as well as the Department of Rehabilitation at the Université Laval in Québec City, QC, Canada.