Comparison between continuous and discontinuous incremental treadmill test to assess the velocity at VO2max

BACKGROUND: The velocity associated with maximum aerobic power (vVO2max) is an important physiological parameter, which is utilized to determine relative workloads on the field. The testing modality adopted to evaluate it, though, may cause differences in v V O2 max assessment and, in turn, in training intensity. The aim of the study was to compare two different testing modalities (continuous incremental ramp and discontinuous square wave (SW) protocols) for vVO2max assessment on the treadmill. METHODS: Seventeen physically active participants performed three maximum incremental tests on a treadmill: two continuous ramp protocols, with different ramp slopes (R1, 1 km·h-1 per min; and R2, 1 km·h-1 every 2 min), and one discontinuous SW protocol, in random order, for maximum oxygen uptake ( VO2max) and vVO2max determination. Cardiorespiratory and metabolic parameters were collected breath-by-breath at rest and during exercise. RESULTS: vVO2 max was significantly higher in R1 and R2 compared to SW (20.7±0.5, 18.6±0.4, 16.8±0.6 km·h-1 for R1, R2, and SW, respectively; P<0.001). No significant differences were found among protocols for VO2 max (56.7±1.1, 57.0±1.2, and 56.6±1.2 ml·min-1·kg-1 for SW, R1, R2, respectively) as well as for expiratory ventilation, carbon dioxide production, blood lactate concentration, and heart rate. CONCLUSION: In spite of similar VO2 max values, vVO2 max was higher during continuous incremental ramp tests compared to SW possibly due to the longer time for cardiorespiratory and metabolic adjustments, suggesting different aerobic and anaerobic metabolism involvement. The differences among protocols should be considered when vVO2 max is used for training purposes.