Anthropology, University of Washington
Saturday All day, Plaza Level
Energy allotted for locomotion cannot be used for growth, maintenance or reproduction; therefore, understanding the factors that influence the amount of energy used is imperative. Because stature and/or leg length can represent size, they influence the amount of energy used in walking, but other morphological parameters are potentially important. In particular, we wondered if measurements of shape would also be predictive of energy expenditure.
Fifteen women walked on a treadmill while their oxygen intake (VO2) and carbon dioxide (VCO2) expiration was monitored at five self-selected walking velocities. Each subject began with four minutes of rest to obtain a standing resting metabolic rate, and then alternated between five minutes of walking and four minutes of rest. We measured the waist, hip, thigh, knee, calf, ankle, and foot circumferences of each subject as well as stature, thigh and calf length, bitrochanteric breadth, and mass.
Bitrochanteric breadth (p < 0.001) and upper calf circumference (p <0.001) explained 82% of the variation in VO2 (R2 = 0.82). Body mass was not a significant predictor of VO2 when bitrochanteric breadth was included in stepwise regression analysis. Additional analysis suggests that VO2 increases with longer legs but decreases as calf length increases (p = 0.048 and 0.028, respectively), but a larger sample size is necessary to study this further.
These results illustrate that morphological factors other than stature and leg length influence energy expenditure. Future work should aim to include the assessment of more morphological variables and obtain larger sample sizes.