Influence of task complexity on mechanical efficiency and propulsion technique during learning of hand rim wheelchair propulsion

Objective: To investigate the consequence of task complexity on gross mechanical efficiency and propulsion technique during the learning process of hand rim wheelchair propulsion. Methods: Three groups of unimpaired subjects (N = 10 each) received a 3-week wheelchair practice period (3 week(-1), nine practice trials) with different levels of complexity, i.e. propelling a stationary wheelchair ergometer, wheelchair propulsion on a motor-driven treadmill or at a circular wheelchair track. During practice trials 1 and 9, gross mechanical efficiency and propulsion technique variables (work per cycle, cycle frequency, push and cycle time, effective force) were measured. Results: Using multi-level regression analysis, no differences in the development over time in mechanical efficiency and propulsion technique could be discerned between the three conditions of task complexity. Only the percentage push time during the cycle decreased significantly more in the group that practiced on the ergometer compared to the treadmill-practice group. For all three groups a change over time was shown for cycle frequency, push time and cycle time. Discussion: Under the current experimental conditions, task complexity does not have an influence on gross mechanical efficiency and propulsion technique during the learning process of wheelchair propulsion. The 3-week practice period had a favorable practice effect on timing regardless of the task complexity. (C) 2004 IPEM. Published by Elsevier Ltd. All rights reserved.