Fig. 5. A schematic representation of the qualitative changes that, on theoretical grounds, might be expected of the efficiency/velocity relationship consequent upon an increase in muscle temperature. In the illustration, the solid line shows the efficiency/velocity relationship for a muscle that has an optimum velocity for maximum efficiency close to 60 revs min^-1 under normal conditions. The dashed line indicates the expected rightward shift consequent upon an increase in muscle temperature. Thus, increasing muscle temperature at 60 revs min^-1 results in a decrease in efficiency from point a to b. In contrast, at a higher movement frequency (120 revs min^-1), efficiency increases from to c to d as a result of the rightward shift in the relationship.