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Updated: Jul 31, 2026

Determining the Contribution of the Energy Systems During Exercise
Published on: March 20, 2012
Aerobic and anaerobic energy conversion during high-intensity exercise
1Department of Sport Sciences, Brunel University, Osterley Campus, Isleworth, Middlesex, United Kingdom. john.ward-smith@brunel.ac.uk
Purpose:
The aim of the study is to compare data on anaerobic and aerobic energy conversion during exercise of high intensity leading to exhaustion. Several different data sources are used, including data extracted from mathematical analyses of world and Olympic running records, data from laboratory tests, and data based on biochemical information.
Methods:
Theoretical relationships are derived and comparisons are made of the ratio of aerobic to total energy contributions as functions of time.
Results:
The ratio is shown to depend not only on the duration of the high-intensity exercise but also in part on a factor lambda, which governs the rate of anaerobic and aerobic energy release. A further important factor is the value of the parameter Q/lambda, which is the ratio of anaerobic capacity to maximum sustainable aerobic power. Values in the range 55 s < Q/lambda < 72 s and 0.030 s(-1) < lambda < 0.042 s(-1) are shown to provide the best correlation of data. The results indicate that the ratio of maximal anaerobic power to maximum aerobic power lies in the range from 2.0 to 2.6.
Conclusion:
Data extracted from the mathematical models of running are generally more consistent than the body of experimental data. This may indicate that the inherent difficulties of laboratory techniques relating to the measurement of anaerobic energy conversion are giving rise to significant experimental errors.
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