Report

Understanding propulsive shoulder forces and scapular kinematics during manual wheelchair use

Shoulder pain and inefficient propulsion are common and disabling problems for wheelchair users.

Lead academic:
Dr Tom Paulson
Additional academics:
Dr Barry Mason, Professor Vicky Tolfrey
Funder:
The Peter Harrison Foundation

However, little is known about how the interaction between wheelchair configuration and users affects shoulder girdle biomechanics

This can impact significantly on performance during activities of daily living (ADL) and sport. The aim of the research was therefore to establish a feasible and reliable method that could be employed to better understand how manipulating wheelchair configuration can minimise future shoulder girdle pain and pathology.

Methods

  • 10 active males, reliant on a manual wheelchair for both ADL and sport (n=5 with shoulder pain, of which n= 3 unilateral).
  • Each participant performed six 4-min submaximal bouts (3, 4 and 6 km.h-1 (T1), repeated following a 20 min rest (T2)) in their personal ADL wheelchair mounted on a wheelchair ergometer.
  • An instrumented measurement wheel examined propulsion kinetics and technique parameters while threedimensional kinematic analysis was used to assess bilateral scapulothoracic rotations (internal/external and upward/ downward, anterior/posterior tilt) over propulsive cycles.

Main findings and applications

  • Push frequency, peak force, contact angle, cycle time and power output were all significantly different between each propulsion speed (p<0.05; Effect size=0.38-0.98)
  • Common to all speeds was an internally rotated and anteriorly tilted scapula.
  • Peak internal rotation of the scapula occurred during the recovery phase of the propulsion cycle and the scapula moved towards a neutral or posteriorly tilted position at ~50% propulsion cycle.
  • Mean (~3º) and peak (~4º) scapular internal rotations were significantly greater at 6 km.h-1 than either of the slower speeds. Intra-investigator reliability for the scapular kinematics was: TE=1.6 to 3.1º; ICC=0.87-0.97.
  • Absolute bilateral asymmetries ranged from 0.5º-16.7º, 0.4º-11.6º and 0.9º-10.7º for internal, upward rotation and anterior/posterior tilt, respectively.
  • Large intra-individual variability was present for bilateral asymmetry with no association between scapular kinematics and self-reported pain symptoms.

Future work

  • This work has established methods and generated an initial database to enable future work understanding how wheelchair configurations can be manipulated to prevent shoulder girdle pain and improve propulsive efficiency. Furthermore we have developed a robust measurement protocol which can be refined to generate real time information assessing the effectiveness of future wheelchair configuration interventions.

Reference

Dr Tom Paulson, Dr Dylan Morrissey (Queen Mary University of London), Dr Barry Mason, Dr Riemer Vegter (University of Groningen), Dr Bertrand Bru (Charnwood Dynamics Ltd, Codamotion), Prof. Lucas van der Woude (University of Groningen) and Prof. Victoria Goosey-Tolfrey. DOI: