title: Influence of task complexity on mechanical efficiency and propulsion technique during learning of hand rim wheelchair propulsion.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Faculty of Human Movement Sciences, The Institute of Fundamental and Clinical Human Movement Sciences (IFKB), Vrije Universiteit, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. s.de.groot@fbw.vu.nl
authors.forename: S
authors.initials: S
authors.lastname: de Groot
authors.forename: H E J
authors.initials: HE
authors.lastname: Veeger
authors.forename: A P
authors.initials: AP
authors.lastname: Hollander
authors.forename: L H V
authors.initials: LH
authors.lastname: van der Woude
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D004735:Energy Transfer / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013314:Stress, Mechanical; D013647:Task Performance and Analysis; D019415:Torque; D014910:Wheelchairs