Position and Movement of Centre of Force During Propulsion of 3 Different one Arm Drive Wheelchairs by Hemiplegic Users

Purpose: This pilot study used a CONFORmat® Pressure mat to measure the position and movement of the centre of force measured at the buttock/seat interface of users whilst seated in three different one arm drive wheelchairs during propulsion. The manual wheelchairs included were: a dual handrim, a lever drive and a Neater Uni-wheelchair. Methods: 15 hemiplegic user’s propelled each wheelchair around an indoor course during which the centre of force was continuously recorded. Position and movements of the centre of force in the anteroposterior and mediolateral directions were recorded. The time taken to complete the circuit was also recorded. Standard deviations and 95% confidence intervals for each participant in each wheelchair were calculated to determine statistically significant differences. Results: Movement of the centre of force was greatest in the dual handrim wheelchair, both antero-posteriorly [F(2,39)= 21.696, p<0.001] and mediolaterally [F(2,39)= 44.273, p<0.001]. Position of the centre of force was also anteriorly displaced in the dual handrim wheelchair, [F(2,39) =15.57, p<0.001]. There were no significant differences in the position of the centre of force in the medio-lateral direction. [F(2,39)= 2.488, p=0.096] Conclusions: The dual handrim wheelchair produced the greatest movement of centre of force and the lever wheelchair produced the least. This may be indicative of the symmetry and stability of seated posture in hemiplegic one arm drive wheelchair users.