Tidal/VT Calibration of the Tymewear Vital Strap Pro Under VST Protocol: Nasal vs. Buccal Route Effects Replicated Across Three Outdoor Studies

The Tymewear Vital Strap Pro (TWP) generates a dimensionless Tidal signal reflecting thoracic strain amplitude per respiratory cycle. Its conversion to tidal volume (VT) requires an individual Tidal/VT ratio sensitive to breathing route. Two prior studies established this: Study 1 (Ricci, 2025; doi:10.5281/zenodo.18667689) documented a +18.8% nasal vs. oral Tidal signal increase at VT1. Study 2 (Ricci, 2026a; doi:10.5281/zenodo.18873288) formalised a four-level hierarchical model (breathing route > position > bicycle type > intensity) with a large nasal vs. oral effect in TT bar position (d=1.06, Δ=+8.7 AU/L). The present study extends this series to an outdoor high-intensity ergometer protocol in a VST-conditioned World Tour cyclist.

One World Tour cyclist (Ath-02; VST ≥2 months) was tested simultaneously with TWP and VO₂ Master Pro across two outdoor sessions (Day J; Day J+1). n=59 total pairs; 1 mixed-route pair excluded → n=58 valid pairs. Conditions: nasal and buccal breathing, 285–455W. Full Bland-Altman analysis; Hedges g; Mann-Whitney U; Welch t (α=0.05).