The present study examined the effect of elevated temperature on muscle energy turnover during dynamic exercise. Nine male subjects performed 10 min dynamic knee-extensor exercise at an intensity of 43 (SD 10) and a frequency of 60 contractions per minute (cpm). Exercise was performed under normal (C) and elevated muscle temperature (HT) through passive heating. Thigh oxygen uptake (VO2) was determined from measurements of thigh blood flow and femoral arterial-venous differences for oxygen content (a-v O2diff). Anaerobic energy turnover was estimated from measurements of lactate release as well as muscle lactate accumulation and PCr utilisation based on analysis of muscle biopsies obtained before and after each exercise. At the start of exercise muscle temperature was 34.5°C (SD 1.7) in C compared to 37.2°C (SD 0.5) during HT (P < 0.05). Thigh VO2 after 3 min was 0.52 l min-1 (SD 0.11) in C and 0.63 l min-1 (SD 0.13) in HT, and at the end of exercise it was 0.60 l min-1 (SD 0.14) and 0.61 l min-1 (SD 0.10) in C and HT, respectively (NS). Total lactate release was the same between the two temperature conditions, as was muscle lactate accumulation and PCr utilisation. Total ATP production (aerobic + anaerobic) was the same between each temperature condition [505.0 mmol kg-1 (SD 107.2) vs. 527.1 mmol kg-1 (SD 117.6); C and HT, respectively]. In conclusion, within the range of temperatures studied, passively increasing muscle temperature prior to exercise has no effect on muscle energy turnover during dynamic exercise.