Article

Repetitive forces and moments are among the work requirements of
hand-rim wheelchair propulsion that are related to shoulder injuries. No previous
research has been published about the influence of power-assisted wheelchair
propulsion on these work requirements. The purpose of our study was therefore to
determine the influence of power-assisted propulsion on shoulder biomechanics and
muscle activation patterns. We also explored the theoretical framework for the
effectiveness of power-assisted propulsion in preventing shoulder injuries by
decreasing the work requirements of hand-rim wheelchair propulsion. METHODS: Nine
non-wheelchair users propelled a hand-rim wheelchair on a treadmill at 0.9m/s.
Shoulder biomechanics, and muscle activation patterns, were compared between
propulsion with and without power-assist. FINDINGS: Propulsion frequency did not
differ significantly between the two conditions (Wilcoxon Signed Rank
test/significance level/effect size:4/.314/-.34). During power-assisted
propulsion we found significantly decreased maximum shoulder flexion and internal
rotation angles (1/.015/-.81 and0/.008/-.89) and decreased peak force on the rim
(0/.008/-.89). This resulted in decreased shoulder flexion, adduction and
internal rotation moments (2/.021/-.77; 0/.008/-.89 and1/.011/-.85) and decreased
forces at the shoulder in the posterior, superior and lateral directions
(2/.021/-.77; 2/.008/-.89 and2/.024/-.75). Muscle activation in the pectoralis
major, posterior deltoid and triceps brachii was also decreased (2/.038/-.69;
1/.015/-.81 and 1/.021/-.77). INTERPRETATION: Power-assist influenced the work
requirements of hand-rim wheelchair propulsion by healthy subjects. It was
primarily the kinetics at rim and shoulder which were influenced by
power-assisted propulsion. Additional research with actual hand-rim wheelchair
users is required before extrapolation to routine clinical practice.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS