Lactate steady state velocity and distance-exhaustion time relationship in running.

The relationship between distance and exhaustion time is linear for running exercise at constant velocity lasting 5 to 45 minutes. The slope of this relationship has the dimension of a velocity (VCRIT) which can be sustained during a long time. The individual VCRIT have been studied in 8 runners by measuring exhaustion time for 4 to 5 constant-velocity running exercises performed to exhaustion. The velocity correspond to a lactate steady state (VCHASSAIN) has been estimated according to a two-step protocol proposed by Chassain for exercises on a cycle ergometer. The running velocity corresponding to maximal aerobic metabolism (VLEGER) was estimated by means of the track test proposed by Léger and Boucher. VCRIT was very well correlated (r greater than 0.97) and almost equal to VCHASSAIN. VLEGER was also very well correlated with VCHASSAIN and VCRIT.