Article Title



For more than 90 years, researchers have utilized incremental protocols to measure maximal oxygen consumption (VO2max). However, more recently there has been research to suggest that a decremental protocol may elicit a higher VO2max than an incremental protocol. PURPOSE: To determine whether a decremental protocol could produce higher VO2max values than an incremental protocol, and to understand the potential mechanism underlying this phenomenon. METHODS: 20 runners/triathletes (mean±SD: age 28.0±6.9 y) were randomized to one of two groups: incremental (n=10) or decremental (n=10). All participants completed an initial incremental VO2max test, followed by a verification phase. Participants in the incremental group then completed two further incremental tests on a treadmill beginning at 5.6 mph (4.4 mph for women) at a 5% grade. Participants in the decremental group completed a second VO2max using the decremental protocol, which was based on the results of their initial incremental test. The decremental group also completed a third VO2max test using the incremental protocol. All testing was separated by at least 72 h. During each test VO2, VCO2, ventilation, and heart rate were measured using a metabolic cart system and cardiac variables were estimated with thoracic bioimpedance. A 2x3 repeated measures ANOVA was conducted with an alpha level set at 0.05. RESULTS: There were no significant main effects for group or interaction over time (p>0.05). Average VO2max over three trials was similar between the incremental (56.4±0.9 ml/kg/min) and decremental (60.8±0.9 ml/kg/min) groups (p>0.05). The average difference in VO2max across the 3 trials was 0.18 ml/kg/min for incremental and 0.24 ml/kg/min for decremental groups (p>0.05). Furthermore, there were no significant differences in average cardiac output (Q) or stroke volume (SV) over three trials between the incremental (Q:23.9±0.6 L/min; SV:126.9±3.2 ml/beat) and decremental groups (Q:20.3±0.5 L/min; SV:108.1±2.9 ml/beat). CONSLUSIONS: The findings of this study suggest that a decremental protocol does not elicit higher VO2max values than an incremental protocol. However, there is evidence to suggest that a decremental protocol can be used as an alternative protocol to measure VO2max in runners and triathletes.

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