Wheelchair propulsion technique and mechanical efficiency after 3 wk of practice

DE GROOT, S., H. E. J. VEEGER, A. P. HOLLANDER, and L. H. V. VAN DER WOUDE. Wheelchair propulsion technique and mechanical efficiency after 3 wk of practice. Med. Sci. Sports Exerc., Vol. 34, No. 5, pp. 756-766, 2002. Purpose: Differences in gross mechanical efficiency between experienced and inexperienced wheelchair users may be brought about by differences in propulsion technique. The purpose of this experiment was to study changes in propulsion technique (defined by force application, left-right symmetry, intercycle variability, and timing) and FOSS mechanical efficiency during a 3-wk wheelchair practice period in a group Of novice able-bodied nonwheelchair users. Methods: Subjects were randomly divided over an experimental group (N = 10) and a control group (N = 10). The experimental group received a 3-wk wheelchair practice period (3-wk(-1). i.e.. 9 practice trials) on a computer-controlled wheelchair ergometer, whereas the control group only participated in trials 1 and 9. During all nine practice trials. propulsion technique variables and mechanical efficiency were measured. Results: No significant differences between the groups were found for force application, leff-right symmetry. and intercycle variability. The push frequency and negative power deflection at the start of the push phase diminished significantly in the experimental group in contrast to the control group (P < 0.05). Work per cycle, Push time, cycle time, and mechanical efficiency increased. Conclusion: The practice period had a favorable effect on some technique variables and mechanical efficiency, which may indicate a positive effect of improved technique on mechanical efficiency. Although muscle activation and kinematic Segment characteristics were not measured in the present study, they may also impact mechanical efficiency. No changes occurred over time in most force application parameters, left-right symmetry. and intercycle variability during the 3-wk practice period however, these variables may change oil another time scale.