The efficiency of cycling and the indirect calorimetric method using the Douglas bag : The effect of pedaling frequency on cycling efficiency, fat and carbohydrate oxidation during submaximal cycling exercise

Purpose: This study was conducted to investigate whether the pedaling frequency at a constant mechanical power contributes to the cycling efficiency (η gross and η net) , and the rate of fat and carbohydrate utilization during submaximal cycling exercise. Methods: Healthy, recreationally active men (n=ll) and women (n=5) cycled 5 min at workloads of about 54 watts at pedaling frequency of 45, 60 and 90 revolutions/min, respectively, and rested 3 min at approximately equal interval until the following step. Results: Mean Gross Efficiency (η gross) significantly decreased from 17.98±1.97% and 16.77±0.94%, at 45 rpm and 60 rpm to 13.44±0.82% at 90 rpm, and Net efficiency (η net) similarly decreased from 25.60±4.75% and 22.45±1.64% at 45 rpm and 60 rpm to 16.97±1.33% at 90 rpm. Although the rate of fat oxidation was not changed in all pedaling frequency, the rate of carbohydrate oxidation gradually rose with increase in pedaling frequency, the rate of carbohydrate oxidation at 90 rpm significantly (p<0.05) increased compared with these at 45 rpm and 60 rpm. Conclusion: These results in the practice biomechanics indicate that these values of η gross and η net indicated in this practice are consistent with those reported previously, and that the η gross and η net decrease and the rate of carbohydrate oxidation gradually increase, with increasing pedal frequency, respectively.

pedaling frequency

gross efficiency

net efficiency

fat and carbohydrate oxidation