Manual wheelchair stroke characteristics during an extended period of propulsion.

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

The purpose of this study was to examine stroke characteristics of long-term manual wheelchair users during an extended manual wheelchair propulsion trial and the extent to which changes in propulsion biomechanics occurred.

SETTING

Human Engineering Research Laboratories, VA Rehabilitation Research and Development Center, VA Pittsburgh Healthcare Systems, Pittsburgh, PA, USA.

METHODS

Kinetic data were recorded from 21 subjects with paraplegia at four time points over the course of a 10-min propulsion trial at a steady state speed of 1.4 m s(-1). Upper extremity kinetic parameters were recorded using Smartwheels, force and torque sensing pushrims.

RESULTS

Subjects for propulsion biomechanics changed from early to late during the 10-min trial. Individuals displayed decreased maximum rate of rise of resultant force (P=0.0045) with a simultaneous increase in push time (P=0.043) and stroke time (P=0.023), whereas stroke frequency remained static. In addition, there was a decrease in out of plane moment application (P=0.032).

CONCLUSION

Individuals seemed to naturally accommodate their propulsive stroke, using less injurious propulsion biomechanics over the course of a 10-minute trial on a dynamometer. The findings may have occurred as a result of both biomechanical compensations to a challenging propulsion trial and accommodation to propelling on a dynamometer. These results suggest that subjects may be capable of independently incorporating favorable biomechanical strategies to meet the demands of a challenging propulsion scenario.