Pedaling rate is an important determinant of human oxygen uptake during exercise on the cycle ergometer

Estimation of human oxygen uptake ([Image: see text]) during exercise is often used as an alternative when its direct measurement is not feasible. The American College of Sports Medicine (ACSM) suggests estimating human [Image: see text] during exercise on a cycle ergometer through an equation that considers individual's body mass and external work rate, but not pedaling rate (PR). We hypothesized that including PR in the ACSM equation would improve its [Image: see text] prediction accuracy. Ten healthy male participants’ (age 19–48 years) were recruited and their steady-state [Image: see text] was recorded on a cycle ergometer for 16 combinations of external work rates (0, 50, 100, and 150 W) and PR (50, 70, 90, and 110 revolutions per minute). [Image: see text] was calculated by means of a new equation, and by the ACSM equation for comparison. Kinematic data were collected by means of an infrared 3-D motion analysis system in order to explore the mechanical determinants of [Image: see text]. Including PR in the ACSM equation improved the accuracy for prediction of sub-maximal [Image: see text] during exercise (mean bias 1.9 vs. 3.3 mL O(2) kg(−1) min(−1)) but it did not affect the accuracy for prediction of maximal [Image: see text] (P > 0.05). Confirming the validity of this new equation, the results were replicated for data reported in the literature in 51 participants. We conclude that PR is an important determinant of human [Image: see text] during cycling exercise, and it should be considered when predicting oxygen consumption.