Date of Award

8-2011

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Kinesiology and Sport Studies

Major Professor

David R. Bassett, Jr.

Committee Members

Dixie L. Thompson, Eugene C. Fitzhugh, Gene A. Hayes, Paul C. Erwin

Abstract

Purpose: To examine the relationship between hand rim propulsion power and energy expenditure during wheelchair locomotion. Methods: Fourteen individuals who used manual wheelchairs were included in this study. Each participant performed five different locomotion activities in a wheelchair with a PowerTap hub built into the rear wheel. The activities included wheeling on a level surface that elicited a low rolling resistance at three different speeds (4.5, 5.5, and 6.5 km∙hr-1), wheeling on a rubberized 400m track that elicited a higher rolling resistance at one speed (5.5 km∙hr-1), and wheeling on a sidewalk course that included uphill and downhill segments at their self-selected speed. Energy expenditure was measured using a portable indirect calorimetry system. In addition, each subject wore an Actical and a SenseWear activity monitor on the right wrist and upper arm, respectively. Stepwise, linear regression was performed to predict energy expenditure from power output variables. A repeated measures ANOVA was used to compare the measured energy expenditure to the estimates from the power models, the Actical, and the SenseWear. Bland-Altman plots were used to assess the agreement between the criterion values and the predicted values. Results: The relationship between energy expenditure and power was significantly correlated (r = 0.694, p < 0.001). Stepwise, linear regression analysis yielded three significant prediction models utilizing measured power; measured power and speed; and measured power, speed, and heart rate. A repeated measures ANOVA demonstrated a significant main effect between measured energy expenditure and estimated energy expenditure (p < 0.01). There were no significant differences between the criterion method and the power models or the Actical. The SenseWear significantly overestimated energy expenditure when wheeling at 4.5 km·hr-1, 5.5 km·hr-1, 6.5 km·hr-1, and during self-paced sidewalk wheeling (p < 0.05). Conclusion: Energy expenditure can be accurately and precisely estimated based on wheelchair propulsion power. These results indicate that wheelchair power could be used as a method to assess physical activity in people who use wheelchairs.

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