Ecological Validation of Ventilatory Strategies Training (VST) Adaptations in a World-Tour Professional Cyclist

Ventilatory Strategies Training (VST) — combining Inspiratory Muscle Training (IMT) with hypercapnic/isocapnic tolerance protocols — has been proposed as an ergogenic intervention targeting respiratory muscle fatigue and the inspiratory metaboreflex in elite endurance athletes. Despite accumulating evidence from controlled laboratory settings, field-based ecological validation integrating simultaneous NIRS, breath-by-breath gas exchange, and longitudinal power-matched data remains absent from the literature. Three field measurement sessions of laboratory grade were performed: Session C (T0, baseline) and Sessions A and B (T12, post-intervention). Results: Rf drift slope 3.61 → 0.74 c/min/min (−79.5%; ÷4.87×). Hedges' g for Rf: −1.35 (large effect). Tv end-of-effort: +21–26%. Mean VE: −22.2% (Hedges' g = −1.26). VO2 τ ≈ 80 s; slow component 6.84–7.82 mL/kg/min. SmO2 quad min1: 24.5% → 7.5%. HR at ~375W: −14 to −17 bpm. Race equivalent: 96–150 sec gained on Alpe d'Huez (18–29 W freed). This case report provides ecologically robust, multi-parameter validation of the Ricci & Bouveort (2025) VST protocol. No population-level inference is claimed.