Determinants of endurance in well-trained cyclists

Fourteen competitive cyclists who possessed a similar maxi-mum 02 consumption (VO 2 max; range, 4.6-5.0 l/min) were com-pared regarding blood lactate responses, glycogen usage, and endurance during submaximal exercise. Seven subjects reached their blood lactate threshold (LT) during exercise of a relatively low intensity (group L) (i.e., 65.8 t 1.7 % 7jozrnax), whereas exercise of a relatively high intensity was required to elicit LT in the other seven men (group H) (i.e., 81.5 k 1.8 % TOM,,; P < 0.001). Time to fatigue during exercise at 88 % of VOLT, was more than twofold longer in group H compared with group L (60.8 k 3.1 vs. 29.1 k 5.0 min; P < 0.001). Over 92 % of the variance in performance was related to the %VO ~ mm at LT and muscle capillary density. The vastus lateralis muscle of group L was stressed more than that of group H during submaximal cycling (i.e., 79 % V0 2 mm), as reflected by more than a twofol