A Popularized Measure Of Anaerobic Capacity May Not Be Valid In Short-Duration Exercise

The gold standard measure of anaerobic contribution is accumulated oxygen deficit (AOD). Calculating AOD is time consuming, as it requires several submaximal exercise tests to estimate oxygen demand. Recent studies have proposed an alternative AOD for measuring anaerobic contributions: this ‘AOD_alt’ provides separate measures of phosphocreatine and glycolysis contributions and requires only one exercise test. PURPOSE: This study aimed to determine the validity of AOD_alt as a measure of anaerobic contribution during constant power, severe intensity, cycle ergometer exercise of different durations. METHODS: Seven women (age 23 ± 3 y, height 169 ± 8 cm, weight 67 ± 12 kg) and thirteen men (22 ± 2 y, 182 ± 9 cm, 78 ± 10 kg) performed three constant power, severe intensity, cycle ergometer tests, which were terminated by the investigators after either 3 min, 6 min, or 9 min, with the order of durations determined using randomization. AOD was calculated as the difference between the estimated oxygen cost of exercise and the accumulated oxygen uptake. AOD_alt was calculated as the sum of the phosphocreatine contribution, estimated from post-exercise VO2, and the glycolysis contribution, estimated from post-exercise blood lactate concentration. Values for AOD and AOD_alt were compared using a two-way repeated-measures analysis of variance (ANOVA; Method x Duration), post hoc t-tests, and Pearson correlation (significance at p < 0.05). RESULTS: The results of the ANOVA revealed significant main effects for Method (AOD_alt > AOD) and for Duration (anaerobic contribution greater in longer tests). There was also a significant interaction effect (p = 0.003). Results of post hoc tests revealed that, in the 9 min tests, AOD_alt was not different from AOD (p = 0.314), correlation r = 0.923 (p < 0.001); in the 6-min tests, AOD_alt was not different from AOD (p = 0.332), correlation r = 0.918 (p < 0.001); and in the 3-min tests, AOD_alt was greater than AOD (p < 0.005), correlation r = 0.765 (p < 0.001). CONCLUSION: These results suggest that AOD_alt may be a valid measure of anaerobic contribution during constant power, severe intensity, cycling exercise of 6 or 9 min duration. However, its applicability to exercise of shorter durations, such as 3 min, may be limited and warrants further research.