Differences in oxygen uptake but equivalent energy expenditure between a brief bout of cycling and running

BACKGROUND We examined aerobic and anaerobic exercise energy expenditure and excess post-exercise oxygen consumption (EPOC) between a 250 Watt, 1-minute bout of cycling and uphill treadmill running. METHODS Fourteen active to well-trained subjects volunteered for the investigation (VO2 max: 57.0 +/- 12.9 ml x kg x min(-1) cycle; 59.3 +/- 13.7 ml x kg x min(-1) run; p = 0.44). Anaerobic energy expenditure was estimated from Deltablood lactate. Statistical analysis was completed using a paired t-test (mean +/- SD). RESULTS Perceived exertion did not differ between exercise bouts (14.0 +/- 2.3 cycle; 13.2 +/- 2.1 run; p = 0.29). Exercise oxygen uptake was significantly greater for running (41.4 +/- 6.9 kJ) compared to cycling (31.7 +/- 7.7 kJ) (p = 0.0001). EPOC was not different between cycling and running (p = 0.21) so that exercise oxygen uptake + EPOC was greater for running (103.0 +/- 13.5 kJ) as compared to cycling (85.4 +/- 20.2 kJ; p = 0.008). Anaerobic energy expenditure was significantly greater for cycling (32.7 +/- 8.9 kJ) versus running (22.5 +/- 11.1 kJ) (p = 0.009). Aerobic + anaerobic exercise energy expenditure (cycle 64.3 +/- 12.2 kJ; run 63.9 +/- 10.1 kJ) (p = 0.90) and total energy expenditure (including EPOC; cycle 118.0 +/- 21.8 kJ; run 125.4 +/- 19.1 kJ; p = 0.36) were similar for cycling and running. CONCLUSION Oxygen-only measures reveal discrepancy in energy expenditure between cycling and uphill running. Measurements of exercise oxygen uptake, Deltablood lactate and a modified EPOC promote the hypothesis of a similarity in exercise and total energy expenditure between 1-minute work-equivalent bouts of cycling and uphill running.