Early motor learning changes in upper-limb dynamics and shoulder complex loading during handrim wheelchair propulsion

Early motor learning changes in upper-limb dynamics and shoulder complex loading during handrim wheelchair propulsion

Vegter, R.J.K.
Hartog, J.
De Groot, S.
Lamoth, C.J.
Bekker, M.J.
Van der Scheer, J.W.
Van der Woude, L.H.V.
Veeger, H.E.J.

Mechanical, Maritime and Materials Engineering

Biomechanical Engineering

2015-03-10

Background To propel in an energy-efficient manner, handrim wheelchair users must learn to control the bimanually applied forces onto the rims, preserving both speed and direction of locomotion. Previous studies have found an increase in mechanical efficiency due to motor learning associated with changes in propulsion technique, but it is unclear in what way the propulsion technique impacts the load on the shoulder complex. The purpose of this study was to evaluate mechanical efficiency, propulsion technique and load on the shoulder complex during the initial stage of motor learning. Methods 15 naive able-bodied participants received 12-minutes uninstructed wheelchair practice on a motor driven treadmill, consisting of three 4-minute blocks separated by two minutes rest. Practice was performed at a fixed belt speed (v?=?1.1 m/s) and constant low-intensity power output (0.2 W/kg). Energy consumption, kinematics and kinetics of propulsion technique were continuously measured. The Delft Shoulder Model was used to calculate net joint moments, muscle activity and glenohumeral reaction force. Results With practice mechanical efficiency increased and propulsion technique changed, reflected by a reduced push frequency and increased work per push, performed over a larger contact angle, with more tangentially applied force and reduced power losses before and after each push. Contrary to our expectations, the above mentioned propulsion technique changes were found together with an increased load on the shoulder complex reflected by higher net moments, a higher total muscle power and higher peak and mean glenohumeral reaction forces. Conclusions It appears that the early stages of motor learning in handrim wheelchair propulsion are indeed associated with improved technique and efficiency due to optimization of the kinematics and dynamics of the upper extremity. This process goes at the cost of an increased muscular effort and mechanical loading of the shoulder complex. This seems to be associated with an unchanged stable function of the trunk and could be due to the early learning phase where participants still have to learn to effectively use the full movement amplitude available within the wheelchair-user combination. Apparently whole body energy efficiency has priority over mechanical loading in the early stages of learning to propel a handrim wheelchair.

(MeSH)
biomechanics
motor learning
rehabilitation
optimization
wheeled mobility

http://resolver.tudelft.nl/uuid:d8961a8a-d99d-47d5-8eab-e1f7fb486e63

https://doi.org/10.1186/s12984-015-0017-5

BioMed Central

1743-0003

http://www.jneuroengrehab.com/content/12/1/26

Journal of NeuroEngineering and Rehabilitation, 12, 2015

Institutional Repository

journal article

© 2015 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.