Effects of the VST Protocol on VO₂ Kinetics during Repeated Supra-Maximal Efforts in WorldTour Cyclists: A Field-Based Observational Study under Ecologically Valid Conditions

This field-based observational study evaluates the acute effects of the BEFORE and AFTER ventilatory strategies of the VST protocol on VO₂ during repeated supra-maximal efforts in six professional WorldTour cyclists with documented functional ventilatory limitation. Participants completed 6 × 30 s Wingate sprints in a single session: 3 sprints WITHOUT strategies, followed by 3 sprints WITH the full VST protocol (BEFORE + DURING + AFTER), under direct real-time guidance. Immediate post-sprint VO₂ (20–30 s post-sprint) was higher WITH VST in 6/6 participants (+14.6% ± 10.5%; W = 21, p = 0.016, r = 0.90). Sprint VO₂ increased in 5/6 participants (+12.0% ± 10.6%; W = 19, p = 0.047, r = 0.73). Mechanical power was preserved (−0.2%). Inter-sprint recovery CV% decreased from 6.1% to 2.9%. The BEFORE effect was profile-dependent (sprinter vs. climber/all-rounder); the AFTER effect was universal. This study constitutes the first in-field introduction of structured ventilatory strategies during supra-maximal efforts in WorldTour cyclists under ecologically valid conditions.