What is biomechanics?
Biomechanics is the science of movement of a living body, including how muscles, bones, tendons, and ligaments work together to produce movement. For a more descriptive definition, you may click on this link.
What was the purpose of this study?
The purpose of this study was to explore whether a 10-minute wheeling trial of fully-mobile, able-bodied participants could be used to represent, or be generalized to manual wheelchair users with spinal cord injury (SCI). This was investigated by examining whether wheeling strategies and biomechanics would change over a 10-minute period in manual wheelchair users (2-27 years’ experience) and in inexperienced, able-bodied individuals. Biomechanical variability over time was also measured to better understand the differences in wheeling between the two groups. In total, 11 able-bodied individuals, and seven manual wheelchair users participated in the study.
Why is studying variability in wheelchair propulsion important?
Studying variability in wheelchair propulsion allows for a greater understanding of the natural range of movements. Attaining a greater sense of this range of natural movements allows for increased confidence in the results of future wheelchair propulsion studies, since movements in this range would not be specifically attributed to the experimental condition. Understanding this variability in 10-minute trials might prove to be helpful in the future for wheelchair training purposes, considering that improvements can be identified with greater confidence if they are outside of the natural variation. Additionally, this study provides insight regarding whether the wheelchair movements observed in able-bodied individuals can be used to represent the movements of manual wheelchair users, which is helpful information if researchers plan to use able-bodied individuals in future wheeling studies relevant to individuals with SCI.
Able-bodied participants may not accurately represent manual wheelchair users in research studies.
The researchers compared several biomechanical variables between able-bodied participants and manual wheelchair users over the wheeling period: velocity, push angle, force (tangential and total), efficiency, and cadence. They discovered a difference in push angle between the manual wheelchair and able-bodied groups. Manual wheelchair users had a greater increase in push angle and applied more total force. These differences were recorded between minute 1 and minute 10 of the trials. The researchers also observed changes in wheeling strategy in three manual wheelchair users and three able-bodied participants. Other than the push angle and force applied, there were no differences calculated between the two groups. However, due to these differences, it may not be appropriate to use able-bodied participants to represent manual wheelchair users with SCI in future studies.
Some considerations for this study:
Despite participants denying feelings of fatigue, it is possible that fatigue may have contributed to any variations in wheeling strategies. Manual wheelchair users utilized their own wheelchairs, which were similar in nature, relatively “lightweight”, and had quick release wheels, whereas able-bodied individuals were provided with an ElevationTM wheelchair, which allowed for adjustments unique to each participant.