Sunday, October 7, 2001 - Physiology
Aerobic and Anaerobic Energy

- By: John Berardi

Finding two coaches that agree on anything is a difficult endeavor. In the world of athletics, certain sports are stepped in tradition, and often this comes at the expense of science. A great example of this is how coaches train their track and field athletes. In a survey, several of the world's elite 800m coaches were asked to quantify the % of energy coming from the aerobic system in the 800m race. These coaches, far from agreeing, argued numbers as low as 35% and as high as 65%. This illustrates that even elite coaches sometimes don't understand the demands of their sport. The purpose of this investigation was to actually measure and quantify the % energy contribution from aerobic and anaerobic energy systems to several track events. This has very important implications for the training and recovery of elite track athletes as well as other athletes training with similar duration exercise.

In this study, 5 elite level 200m, 400m, 800m, and 1500m runners were selected, for a total of 20 subjects. Runners were asked to run on a treadmill at velocities similar to their own personal best race paces. Expired gasses were collected to quantify the amount of energy derived from the aerobic systems and the anaerobic systems.

It appears that the crossover from mostly anaerobic energy use to aerobic energy use occurs between 15-30 seconds. Broken down by race:
200m run: 29% aerobic; 71% anaerobic
400m run: 43% aerobic; 57% anaerobic
800m run: 66% aerobic: 34% anaerobic
1500m run: 84% aerobic; 16% anaerobic

The authors of this study concluded that the relative contribution of the aerobic energy system during track running events is greater than traditionally thought.

These data are at odds with data from several studies done in the 60's and 70's. Methodologies back then were poor and the aerobic costs of shorter bouts of exercise were underestimated. New studies such as this one make it clear that even during events traditionally considered anaerobic, the aerobic system makes a substantial contribution. Modern sprint athletes now have the benefit of understanding that even they need to spend some time focusing on the aerobic energy system for maximal performance.

1) Energy system contribution during 200m to 1500m running in highly trained athletes. M. Spenser and P Gastin. Med. Sci. Sports Exerc., Vol 33, No.1, 2001, pp 157-162.

John M Berardi is a scientist and PhD candidate in the area of Exercise and Nutritional Biochemistry at the University of Western Ontario, Canada. His company Science Link: Translating Research into Results' specializes in providing integrated training, nutritional, and supplementation programs for high-level strength and endurance athletes. You can contact Science Link at:

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