What Is the Importance of the Anaerobic Threshold to a Marathon Runner?
Anaerobic threshold is an important, and often misunderstood, contributor to marathon performance. Sometimes confused with lactate threshold, the anaerobic threshold refers to an increase in the volume of carbon dioxide produced per minute relative to an athlete's oxygen consumption. Under most conditions, the anaerobic threshold and lactate threshold are very similar and have important implications for performance and training.
Measuring Anaerobic Threshold
A ventilation test in a laboratory measures anaerobic threshold. This value is obtained by determining when the ratio of the volume of air ventilating the lungs to the volume of oxygen consumed shows a sharp increase as the equivalent for carbon dioxide remains stable. This value relies on the fact that carbon dioxide is a byproduct of lactic acid production, and anaerobic threshold provides an estimate of the accumulation of lactic acid in the bloodstream.
Contributions to Performance
Anaerobic threshold has significant contributions to athletic events of all types -- particularly long-distance running. The accumulation of lactic acid in the bloodstream causes a pH imbalance and results in the burning feeling in the muscles that marathoners know all too well. A highly trained runner can work at a much higher percentage of maximal oxygen consumption without lactic acid building up than an untrained runner. Elite runners can run at about 80 to 90 percent of their VO2 max without "going anaerobic," while untrained runners accumulate lactic acid at about 55 percent.
Contrary to popular belief, long-distance runners need to perform high-intensity interval work to improve their anaerobic threshold. While long, slow distance running may help marathoners achieve some performance gains, it's now well understood that training intervals with a 1:1 ratio of work to rest are optimal for improving the anaerobic threshold and allowing runners to work at a higher intensity without accumulating lactic acid.
When planning a training program, schedule several weeks for building a solid base of aerobic endurance. You need about eight weeks of long-distance running to build such endurance. Next spend four to eight weeks building anaerobic threshold. About twice each week, perform interval runs at 85 to 90 percent of your maximum heart rate to fatigue, followed by periods of active rest of the same duration. Progressively increase the intensity of these work intervals, as well as the duration, to improve anaerobic threshold.
- Physiology of Sports and Exercise (3rd Ed.); Jack H. Wilmore and David L. costiLL
- Rice University: Anaerobic Threshold
- Essentials of Strength Training and Conditioning (3rd Ed.); Thomas R. Baechle and Roger W. Earle
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