The incidence of plateau at VO(2max) is affected by a bout of prior-priming exercise.

The purpose of this study was to determine the effect of 6 min of prior-priming exercise on the incidence of plateau at VO(2max). Twelve trained cyclists (age, 21 ± 3 years; height, 175·0 ± 8·0 cm; weight, 69·0 ± 10·4 kg; maximal oxygen uptake (VO(2max)), 56·3 ± 6·9 ml kg(-1) min(-1)) completed three incremental tests to volitional exhaustion, which were classified as unprimed (UP), heavy-primed (HP) and severe-primed (SP), at a work rate of 1 W 2 s(-1), from an initial workload of 100 W, for the determination of VO(2max). VO(2max) trial in the HP and SP conditions was preceded by a period of 4-min unloaded cycling followed by a further 6 min of constant load cycling at Δ50% VO(2) gas exchange threshold (GET)-VO(2max) (HP) and Δ75% VO(2) GET-VO(2max) (SP). Expired air was recorded on a breath-by-breath basis during all trials. The criteria adopted for a plateau in VO(2max) was a ΔVO(2) over the final two consecutive 30-s sampling periods ≤ 2·1 ml kg(-1) min(-1). There was a significant increase in plateau responses between the UP (50%) and HP (100%) conditions (P = 0·001) coupled with a significant change in the slope of the regression line during the final 60 s of the VO(2max) test, UP and HP (P = 0·0299) and UP and SP (P = 0·0296). These data suggest that a bout of prior-priming exercise promotes an increased incidence of plateau responses at VO(2max) . It is suggested that future studies address how such an approach can be adopted without prior knowledge of GET.