Lactate Threshold

The lactate threshold is the training intensity at which the concentration lactate starts to accumulate in the blood stream. Lactate, or rather lactic-acid, is a by product of the anaerobic glycolysis, which is an system which produces ATP at higher exercise intensities or when the aerobic energy systems are not yet able to generate the necessary ATP.

At which intensity the lactate threshold occurs strongly depends on training status, which means that it can take place at a higher intensity after an effective training program. In untrained people the lactate threshold normally occurs aroun 50-60% VO2max, while in endurance trained athletes it can occur at 70-80% VO2max or even higher. The lactate threshold is a determining factor for endurance exercise.

References:

-Baechle, T.R., Earle, W.R. (2008). Bioenergetics of Exercise and Training. Essentials of Strength Training and Conditioning. Third Edition. USA. Human Kinetics.

-Wilmore, J.H., Costill, D.L., Kenney, W.L. (2008). Energy expenditure and Fatigue. Physiology of Sport and Exercise Fourth Edition. USA Human Kinetics.