Comparison of Oxygen Uptake Kinetics During Severe-intensity Laboratory and Field Cycling

The O 2 -kinetic response to constant work rate exercise provides an insight into the adjustment of systemic oxygen transport and muscle metabolism. Whether O 2 -kinetics measured in laboratory conditions reflect O 2 -kinetics in field conditions has not yet been analysed. The aim of this study was to compare O 2 -kinetics between field and laboratory conditions. Thirteen competitive male cyclists (mean±SD age 23.3±4.1 years; VO 2peak 68.2±4.7 mL . min −1. kg −1 ) completed two 6-min severe-intensity trials at 60 and 90 rev . min −1 in both conditions. Power output was measured with an SRM power meter and VO 2 was measured with a portable gas analyser. The time constant (τ), the time delay (TD) and the amplitude (Amp) were resolved by least square regression, and the VO 2 slow component (SC) was calculated as the difference between the end-exercise VO 2 and Amp. To determine differences between the trials, a repeated-measure ANOVA was conducted. The Amp and end-exercise VO 2 were significantly higher during field cycling whereas the SC were significantly higher during laboratory cycling (all at p