Fitness professionals use a variety of tests to predict athletic performance. Lactate threshold is one of those predictors. Lactate threshold is when the rate of lactate production exceeds the rate of lactate removal. Therefore, the level of lactic acid in the blood moves beyond a steady state and begins to increase. Once this happens the muscles are unable to contract efficiently and properly.
Determination
Determining lactate threshold can be done through either direct or indirect methods. The direct method requires an athlete to simulate their sport in a laboratory setting. Typically the athlete participates in a warm up and then progresses into a workout where the workload, or intensity, is systematically increased. To determine the amount of lactic acid in the blood, samples are drawn during each workload. The threshold is the point, or intensity, at which there is an increase in blood lactate concentration. Because it is not always feasible to perform lab draws, an indirect method to measure, or predict, lactate threshold has been developed. Ventilatory threshold, or the point at which your rate of breathing rapidly increases during incremental exercise, has been correlated to occur at the same time as your lactate threshold. While this is not the most accurate method, it is useful in predicting your lactate threshold.
VO2 Max
Maximum oxygen uptake, or VO2 max, is the point at which the body reaches maximum exercise capacity. It is used to predict your level of cardiovascular fitness, as it directly correlates with the functional capacity of the heart. Lactate threshold is often expressed as a percentage of VO2 max. MarathonPal.com estimates that untrained individuals usually have a lactate threshold that occurs at approximately 60 percent of their VO2 max. Moderately trained athletes usually have a lactate threshold between 65 and 80 percent of their VO2 max, while elite fall between 85 and 95 percent. As MarathonPal.com points out, some of these levels can be attributed to genetics. Both can be altered with regular cardiovascular training.
Training Use
Lactate threshold is often affiliated with muscular fatigue and burn felt with prolonged exercise. It is not lactic acid that is responsible for the fatigue and burn, it just so happens that it occurs at the same time as other physiological responses to exercise. The lactate threshold is the intensity at which an athlete can perform for a long period of time. It is that threshold at which the production of lactate and the removal are at equilibrium. Having the knowledge of what intensity that occurs allows fitness professionals to prepare athletes for competition. For example, a runner can benefit by selecting a race pace that she needs to maintain to efficiently finish a race and avoid fatigue.
Improvement of Lactate Threshold
It is possible to improve your lactate threshold through regular cardiovascular training. Dr. Len Kravitz of the University of New Mexico cites several studies that support high-volume, interval training to improve lactate threshold. MarathonPal.com also supports periods of training intensity at or above lactate threshold to improve it.
References
- University of New Mexico: Lactate Threshold Training
- MarathonPal.com: Lactate Threshold
- "Exercise Physiology: Theory and Application to Fitness and Performance," 6th edition; Scott Powers, Edward Howley; 2006
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