Background: The purpose of this study was to assess the relationship between power output and relative power output at the functional threshold power, ventilatory threshold and respiratory compensation point in road cyclists.
Methods: Forty-six road cyclists (age 38±9 years; height 177±9 cm; body mass 71.4±8.6 kg; Body Mass Index 22.7±2.2 kg·m-1; fat mass 7.8±4%, V̇O<inf>2max</inf> 61.1±9.1 mL·min-1·kg-1) performed a graded exercise test in which power output and relative power output at the ventilatory landmarks were identified. Functional threshold power was established as 95% of the power output during a 20-minute test.
Results: Power output and relative power output at the functional threshold power were higher than at the ventilatory threshold (P<0.001). There were very large to near perfect correlations for power output (95% CI for r from 0.71 to 0.9) and relative power output (95% CI for r from 0.79 to 0.93) at the functional threshold power and respiratory compensation point. Mean bias in power output and relative power output measured at RCP compared with FTP was not significant (mean bias 95% CI from -7 to 10 W and -0.1 to 0.1 W/kg, respectively).
Conclusions: Power output and relative power output at the functional threshold power are higher than at the ventilatory threshold. Power output and relative power output at the functional threshold power and respiratory compensation point are strongly related, but caution is required when using both concepts indistinctly.