Effect of muscle temperature on rate of oxygen uptake during exercise in humans at different contraction frequencies

The effect of elevated human muscle temperature on energy turnover was investigated during cycling exercise (at 85 % of V-O2max) at a contraction frequency of 60revs min(-1). Muscle temperature was passively elevated prior to exercise by immersion of the legs in a hot water bath (42degreesC). During exercise at this low pedalling rate, total energy turnover was higher (P<0.05) when muscle temperature was elevated compared with normal temperature (70.4+/-3.7 versus 66.9+/-2.4kJ min(-1), respectively). Estimated net mechanical efficiency was found to be lower when muscle temperature was elevated. A second experiment was conducted in which the effect of elevated human muscle temperature on energy turnover was investigated during cycling exercise (at 85 % of V-O2max) at a contraction frequency of 120 revs min(-1). Under the conditions of a high pedalling frequency, an elevated muscle temperature resulted in a lower energy turnover (P