On the reproducibility of oxygen uptake kinetics during heavy exercise

Abstract

While the equations of Lamarra and colleagues remain the standard for a priori determination of adequate exercise transitions, if subject/patient populations do not allow for adequate laboratory visits, parameter estimation based on a single transition may be required. Thus, the purpose of this study was to examine the short‐term reproducibility of oxygen uptake kinetics during heavy intensity cycling. Fourteen amateur competitive cyclists (mean ± SE age = 30 ± 1.9; V̇O2max = 4.477 ± 0.280 l min−1) completed three constant workrate bouts in the heavy intensity domain. Breath‐by‐breath data were filtered (2.58 SD), combined, averaged, interpolated and characterized with least‐squares non‐linear regression modeling. No significant differences (P > 0.05) were observed across the 3 trials for the fundamental time constant (τ) (F(2,26) = 2.771), fundamental amplitude (F(2,26) = 0.013), or slow component magnitude (F(2,26) = 0.751). Intraclass correlation coefficient revealed good reliability for the fundamental τ (ICC(2,1) = 0.86), fundamental amplitude (ICC(2,1) = 0.98), and slow component (ICC(2,1) = 0.92). While confidence in parameter estimation may be greatly improved by combining multiple exercise transitions, these data indicated good reproducibility and the possibility of utilizing single exercise transitions. This research was not supported by external financial sources.