The aim of this study was to compare V·O2 kinetics of highly- versus recreationally-trained subjects during a constant velocity test of supramaximal intensity. Eighteen trained male subjects were recruited to one of two groups: highly trained (HT, n = 8, V·O2max = 70.1 ± 6.5 ml · min-1 · kg-1) and recreationally trained (RT, n = 10, V·O2max = 63.2 ± 6.4 ml · min-1 · kg-1). All subjects performed an incremental test to exhaustion for the determination of V·O2max and peak treadmill velocity (PTV), two constant velocity tests at 110 % of PTV to determine V·O2 kinetics and oxygen deficit (O2def), and a 800-m time trial to determine running performance (mean velocity over the distance, V800 m). We found significant differences between HT and RT for the on-transient of the V·O2 response (t, 24.7 ± 3.3 and 30.9 ± 7.0 s, respectively), the amplitude of the V·O2 response (60.0 ± 5.0 and 53.5 ± 5.7 ml · min-1 · kg-1, respectively) and V800 m (6.27 ± 2.1 and 5.45 ± 0.38 m · s-1, respectively). O2def (24.6 ± 2.7 and 27.7 ± 7.8 ml · kg-1, respectively) and the gain of the V·O2 response (193 ± 14 and 194 ± 13 ml · kg-1 · m-1, respectively) were similar between groups. t was associated with O2def (r = 0.90, p < 0.05), but not with V800 m (r = 0.30, p > 0.05). It was concluded that HT subjects exhibited faster on-kinetics and higher amplitude than their RT counterparts. The higher amplitude was not thought to reflect any difference in underlying physiological mechanisms. The faster t, whose exact mechanisms remain to be elucidated, may have practical implications for coaches.
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