The V'O_2max measurement has become customary in exercise physiology, not only for classifying a population based on the performance level, but also as a tool to study the integrated responses of the respiratory, cardiovascular and muscular systems in distinct environmental conditions. The classical V'O_2max testing protocol, i.e. incremental discontinuous steady state protocol (IST), has been progressively replaced by the continuous ramp protocols (IRT). IRTs are unsteady state protocols, with shorter step duration than required to attain a metabolic steady state. Since the determinations of V'O_2max and maximal mechanical aerobic power (w'_max) are often coupled, we speculate that a higher mechanical power (w'_peak) than w'_max is reached at the end of IRT, as O₂ consumption associated with any submaximal power should be lower than V'O_2ss during IRT.

Methods 

Seventeen men completed a 5-min IST and a 1-min IRT cycling test. We measured respiratory variables and heart rate (HR) continuously, plus peak lactate concentration ([La]_b). Anaerobic threshold (AT) in IST and ventilatory threshold (VT) in IRT were also assessed.

Results 

Although V'O_2max was equal (IST 3.57±0.42 l/min vs IRT 3.78±0.47 l/min), w'_peak (300±32 W) was higher than w'_max (251±29 W). Maximal HR (IST 185±8 min^-1 vs IRT 183±11 min^-1) and [La]_b (IST 12.33±4.53 mM vs IRT 12.26±3.26 mM) were the same. VT was reached at the same power but at significantly lower V'O₂ (VT 2.42±0.58 l/min vs AT 2.65±0.41 l/min) than AT.

Conclusions 

Both protocols can be conveniently used to determine V'O_2max. In contrast, the higher w'_peak than w'_max speaks against the applicability of IRT when a precise assessment of w'_max is needed. Accordingly, an underestimate of V'O₂ at VT with respect to AT was implied.