Wheelchair Propulsion Training

Principal Investigator: Michael L. Boninger, M.D.

Funding Source: National Institutes of Health

2006-2008

Manual wheelchair users are at high risk of developing upper limb pain. Recent research, which includes work complete at our center and ergonomics literature point to specific propulsion techniques that may prevent injury. The specific aims of this proposal were to 1) Develop wheelchair propulsion-training programs that minimized potential injurious biomechanics; 2) Test if the training programs can cause lasting changes in propulsion biomechanics; and 3) To determine if the addition of real time feedback to a multimedia program is better than a multimedia program alone at improving propulsion mechanics and maintaining improvements over time. The study design was a longitudinal controlled trial with a control group, a multimedia group, and a multimedia and real-time feedback group. Training occurred over three weeks and subjects were followed for three months.
 

A total of 28 long time manual wheelchair users (4 female and 24 male) were enrolled in this study. Specific aim 1 was achieved by developing a wheelchair propulsion training program based on biomechanical literature, clinical practice guidelines, ergonomic principles and motor learning theory. The program was designed to teach efficient propulsion technique which may help minimize the development of upper extremity pain and injury. The two interventions created as a part of the training study were a real time biomechanical feedback (RTF) software display and a multimedia instructional program (MMP). The MMP was an automated instructional video and slide presentation highlighting common injuries that occur as a result of propulsion and how to use specific propulsion techniques to minimize their development. The RTF component of the study, incorporated principles of motor learning theory translated into visual feedback-learning software presenting the same key spatio-temporal and kinetic variables as explained by the MMP. This included minimizing the number of real time feedback variables presented simultaneously while displaying them discontinuously and in random order between training and rest periods. Contact  angle (CA) (degrees pushed during each propulsive phase), velocity (m/s), and cadence (strokes/sec) were the feedback variables selected because they have been shown to have a strong association with the development of upper limb impairments. The presentation of cadence and push angle feedback ultimately encouraged subjects to take longer, less frequent strokes, to decrease force exerted at a given velocity, without causing unintended changes in force direction.
 

To investigate specific aim 2, data was collected for all subjects at a self selected and pre determined velocity during propulsion on a dynamometer, carpet, ramp and tile. Preliminary analysis of data from 22 individuals revealed that as hypothesized, the treatment groups (FB and IO) displayed statistically significant favorable biomechanical changes pre to post training (baseline to 3 months) compared to the CG. Although analysis for all conditions is not complete, the FB group did not consistently display statistically significantly differences from the IO group.
 

For specific aim 3, full statistical analysis for long term change (baseline-3months post training) has been performed for the self selected speeds conditions on the dynamometer and ramp. Main effect statistical findings indicate that while propelling on a dynamometer 3 months after training, both FB and IO treatment groups displayed a statistically significant change (increase) in contact angle where control group CG subjects remained nearly static (p =.001). The interaction contrast effects showed that both FB and IO groups each displayed significant increases in contact angle compared to the CG (p =.001) however significant difference were not found between FB and IO groups (p =.216). Statistical significance was also found in cadence (decrease) pre to post training both in main effect (p =.014) and between the IO and CG groups (p =.007). The change in cadence of the FB group compared to both IO and CG were not found to be significant (p =.24, p =.11). In addition, subject age was found to be a significant predictor of contact angle size on the dynamometer at baseline and 3 months post training for all groups(p =.047). Sex, level of injury, and weight were not found to be predictors of contact angle or frequency. For the ramp condition, significance was found in the main effect for change in contact angle (increase) (p=.021) and with the FB group compared to the CG (p=.006). Comparisons of IO to CG and FB to IO were not found to be statistically significant (p =.17, p =.09). Main effect changes in cadence were not found to be statistically significant (p=.2).
 

We are no longer enrolling participants in this study. Data analysis is ongoing. A manuscript is in review related to manual wheelchair propulsion training using biomechanical real time visual feedback. It is our hope that the design of a training program can help to minimize the upper extremity pain and injury often associated with manual wheelchair propulsion. In the future, these experiments may assist clinicians in training patients in manual wheelchair propulsion.