Comparing results of various training studies is often confounded by use of different indices of exercise intensity. Two frequently used indices are: 1) the % HR max method (exercise at a HR corresponding to a chosen percentage of maximal HR), and 2) this study, % net VO2max was employed as the criterion measure of exercise intensity and a comparison was made between the prediction of % net VO2-MAXby the above two methods. Experiments were performed on nine males (M +/- SD age = 23.7 +/- 2.6 yrs) and consisted of double determinations of resting VO2 and multiple measurements of resting HR under five different conditions. Duplicate determinations of maximal VO2 and HR preceded a third treadmill test consisting of four, 5-minute workloads representing approx 25, 45, 65, and 85% net VO2max. The results demonstrated that the KM's prediction of exercise intensity was not significantly different (P greater than 0.05) from measured intensity at any of the four workloads. Additionally, the % HR max procedure yielded large, significant overpredictions of exercise intensity (29, 22, 16 and 8% overpredictions for the four submaximal intensities, respectively. These results suggest that the KM yields a training HR that reflects exercise intensity within reasonable limits of accuracy.