An inverse relationship between the cost of static posture and the cost of cycling?

To test the hypothesis that both species and individuals with low metabolic costs in locomotion have high energetic costs in maintaining static posture (and vice versa), energy expenditure was measured in men engaged in different activities. Subjects were asked to exercise on a cycle ergometer at different speeds at constant work rates and to maintain a set isometric tension when sitting using different angles of the knee. Individuals with a low energy cost of sitting (minus BMR) had a high energy cost of cycling at 50 rev/min at an external work rate of 25 W (minus energy cost in a sitting position on the cycle). However, there was no significant correlation between the energy cost during a dynamic cycling task and the energy cost during maintenance of a standardized static posture. These findings suggest that mechanisms involved in the conservation of energy expended during cycling may be different from those involved during maintenance of standardized static postures. Curves relating energy expenditure to speed (for a constant work rate) were remarkably flat in the range 20-70 rev/min, indicating a difference in the way energy is conserved in cycling and within gaits. © 1992 Wiley-Liss, Inc.