Because of the limited phosphagen stores and maximal attainable lactate concentration in muscle, it is assumed that the anaerobic energy production (Ean) has a maximum: the anaerobic capacity. Two minutes of exhausting exercise is assumed to be required for maximal use of anaerobic sources. In time trial events in cycling (500-3000m), we found indications that two minutes might not be sufficient to fully utilize the anaerobic capacity. Purpose To determine if the anaerobic capacity can be fully utilized in two minutes of supramaximal exercise. Methods Because the nature of speed skating emphasizes the importance of the anaerobic system, elite level speed skaters (n=8) performed a 1500m speed skating race (lasting about 2 min) and sub-maximal efficiency tests. Depending on their specialization, pairs of skaters also skated a 500m, 1000m, 3000m or 5000m. Final time is recorded for all distances. External energy production (Eext) was calculated using aerodynamic models, taking data from video analysis and ice friction measurements as input. The mechanical equivalent of aerobic energy production (Eaer) was calculated from breath-by-breath VO2 and the measured skating efficiency. Ean was determined by subtracting Eaer from Eext. The relative contribution of Ean to the total energy production was calculated (%Ean). Ean on the 500, 1000, 3000 and 5000m was related to the subject`s Ean on the 1500m. Results %Ean is considerable for every skated distance. Furthermore, the results show that Ean increases with the duration of the event. Conclusion The anaerobic contribution is substantial in all distances. The present results show that, in accordance with literature, distances < 1500m are too short to fully utilize anaerobic capacity. For the longer distances, Ean exceeds the value as measured at the 1500m, so it can be concluded that even in an exercise of highly anaerobic nature the anaerobic capacity is not fully taxed in the time span as is suggested in literature.
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