title: Effects of visual feedback-induced variability on motor learning of handrim wheelchair propulsion.
abstract: BACKGROUND
  It has been suggested that a higher intra-individual variability benefits the motor learning of wheelchair propulsion. The present study evaluated whether feedback-induced variability on wheelchair propulsion technique variables would also enhance the motor learning process. Learning was operationalized as an improvement in mechanical efficiency and propulsion technique, which are thought to be closely related during the learning process.
  
  
  METHODS
  17 Participants received visual feedback-based practice (feedback group) and 15 participants received regular practice (natural learning group). Both groups received equal practice dose of 80 min, over 3 weeks, at 0.24 W/kg at a treadmill speed of 1.11 m/s. To compare both groups the pre- and post-test were performed without feedback. The feedback group received real-time visual feedback on seven propulsion variables with instruction to manipulate the presented variable to achieve the highest possible variability (1st 4-min block) and optimize it in the prescribed direction (2nd 4-min block). To increase motor exploration the participants were unaware of the exact variable they received feedback on. Energy consumption and the propulsion technique variables with their respective coefficient of variation were calculated to evaluate the amount of intra-individual variability.
  
  
  RESULTS
  The feedback group, which practiced with higher intra-individual variability, improved the propulsion technique between pre- and post-test to the same extent as the natural learning group. Mechanical efficiency improved between pre- and post-test in the natural learning group but remained unchanged in the feedback group.
  
  
  CONCLUSIONS
  These results suggest that feedback-induced variability inhibited the improvement in mechanical efficiency. Moreover, since both groups improved propulsion technique but only the natural learning group improved mechanical efficiency, it can be concluded that the improvement in mechanical efficiency and propulsion technique do not always appear simultaneously during the motor learning process. Their relationship is most likely modified by other factors such as the amount of the intra-individual variability.
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands.
authors.forename: Marika T
authors.initials: MT
authors.lastname: Leving
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands.
authors.forename: Riemer J K
authors.initials: RJ
authors.lastname: Vegter
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands.
authors.forename: Johanneke
authors.initials: J
authors.lastname: Hartog
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands.
authors.forename: Claudine J C
authors.initials: CJ
authors.lastname: Lamoth
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands; Amsterdam Rehabilitation Research Center | Reade, Amsterdam, the Netherlands.
authors.forename: Sonja
authors.initials: S
authors.lastname: de Groot
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Center for Rehabilitation, Groningen, The Netherlands.
authors.forename: Lucas H V
authors.initials: LH
authors.lastname: van der Woude
mesh_terms: D001696:Biomechanical Phenomena; D056228:Feedback, Sensory / Q000502:physiology*; D006801:Humans; D007858:Learning; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009068:Movement; D055361:Multilevel Analysis; D014910:Wheelchairs; D055815:Young Adult