Upper limb joint kinetics during manual wheelchair propulsion in patients with different levels of spinal cord injury

The purpose of this study was to compare the forces and moments of the whole upper limb, analyzing forces and moments at the shoulder, elbow and wrist joints simultaneously during manual wheelchair propulsion of persons with different levels of spinal cord injury (SCI) on a treadmill. Fifty-one people participated in this study and were grouped by their level of SCI: C6 tetraplegia (G1), C7 tetraplegia (G2), high paraplegia (G3), and low paraplegia (G4). An inverse dynamic model was defined to compute net joint forces and moments from segment kinematics, the forces acting on the pushrim, and subject anthropometrics. Right side, upper limb kinematic data were collected with four camcorders (Kinescan–IBV). Kinetic data were recorded by replacing the wheels with SmartWheels (Three Rivers Holdings, LLC). All participants propelled the wheelchair at 3 km/h for 1 min. The most noteworthy findings in both our tetraplegic groups in relation to paraplegic groups were increased superior joint forces in the shoulder (G1 and G2 vs G3 p<0.001; G1 and G2 vs G4 p<0.01), elbow (G1 vs G3 p<0.001; G1 vs G4 p<0.05) and wrist (G1 vs G4 p<0.001), an increased adduction moment in the shoulder (G1 vs G3 p<0.001; G1 vs G4 p<0.01; G2 vs G3 and G4 p<0.05) and the constancy of the moments of force of the wrist the fact that they reached their lowest values in the tetraplegic groups. This pattern may increase the risk of developing upper limb overuse injuries in tetraplegic subjects.