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Updated: Aug 29, 2026

Determining the Contribution of the Energy Systems During Exercise
Published on: March 20, 2012
[Energy cost of running during a specific transition in duathlon]
Jean-Marc Vallier1, Cyrille Mazure, Christophe Hausswirth
1Laboratoire Ergonomie Sportive et Performance, Université de Toulon-Var, 83957 La Garde, France.
Abstract:
The aim of the present study was to investigate the variability of the energy cost of running (Cr) during a simulated duathlon performed in outdoor conditions by elite duathletes. This duathlon consisted of 5 km of running, 30 km of cycling, and 5 km of running. The main result was the lack of significant difference in Cr between the two running bouts (210 +/- 10 mL d'O2.km-1.kg-1 vs. 217 +/- 10 mL d'O2.km-1.kg-1). This result is different from those observed during a triathlon, where an increase of energy cost of running bout has been reported. Furthermore, during a short-distance duathlon performed by well-trained subjects, none of the physiological (ventilation alteration, metabolic changes, or dehydration) or biomechanical factors that are classically evoked in triathlon research to explain Cr variability seem to be affected by the run-cycle-run transition. These results seem to minimize the negative effect of the cycle-to-run transition during a short-duration event in well-trained subjects.
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