Pattern of venous lactate and pyruvate after submaximal exercise in athletes training in different disciplines.

The differences in the distribution pattern of muscle fiber types between short-, middle-, and long-distance runners are well known. Since slow- and fast-twitch muscle fibers have different oxidative and glycolytic activities, lactate and pyruvate blood concentrations are expected to behave differently in athletes training in different sports disciplines after short exercise. Twenty-four well-trained athletes participated in the present study. The purpose of the investigation was to examine lactate and pyruvate blood concentrations during a 5-min treadmill exercise test at 6 km/h with a slope of 10% in short-, middle-, and long-distance runners and athletes of other disciplines (nonrunners). The highest and lowest post-exercise lactate and pyruvate levels were found in the short- and long-distance runners, respectively. In contrast to what was found in all other athletes, a decrease of the lactate-pyruvate ratio was observed in the middle-distance runners after exercise. The combination of both aerobic and anaerobic training in these athletes could account for this observation.