What does this research mean for the field?

Nasal breathing significantly amplifies the Tidal signal during cycling, particularly in aerodynamic positions. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

The aim is to assess the effects of breathing route, body position, and bicycle type on tidal volume estimation using the Tymewear Vital Strap Pro during cycling.

March 7, 2026Open Access

Tidal Signal of the Tymewear Vital Strap Pro During Cycling: Role of Breathing Route, Body Position and Bicycle Type — A Complete Bland-Altman Analysis with Hierarchical Biomechanical Modelling

Key Points

The aim is to assess the effects of breathing route, body position, and bicycle type on tidal volume estimation using the Tymewear Vital Strap Pro during cycling.
Conducted a field study with an elite cyclist measuring tidal signals under various conditions.
Collected 67 simultaneous measurements from the Tymewear Vital Strap Pro and VO2 Master Pro across diverse outdoor settings.
Performed comprehensive statistical analyses including Bland-Altman and regression techniques.
Achieved global respiratory rate accuracy with a bias of +0.300 bpm and a narrow limits of agreement.
Nasal breathing significantly enhanced the tidal signal particularly in a TT bike position, showing a large effect size.
Demonstrated a posture gradient in tidal signal amplitude when nasal breathing across different bike setups.

Abstract

Background. The Tymewear Vital Strap Pro (TWP) generates a dimensionless Tidal signal reflecting thoracic excursion amplitude per respiratory cycle. Converting this signal to absolute tidal volume (VT) requires an individual Tidal/VT ratio whose sensitivity to measurement condition has not been systematically characterised in field cycling. A companion ergometer study (Ricci, 2025) established near-perfect RR accuracy (r=0.9996, LoA ±0.6 bpm) and a +18.8% nasal vs. oral Tidal signal increase at VT1 via four hypothesised mechanisms (H1-H4). The present study extends this analysis to outdoor field conditions across two bicycle types and five postural configurations.Methods. One elite competitive cyclist (Ath-01, anonymised; VST-conditioned; VO2max 91-93 ml/kg/min) was recruited and tested by the author (C. Ricci, operator and researcher). A total of n=67 simultaneous TWP/VO2 Master Pro measurement pairs were recorded across five outdoor field conditions: road oral (n=36), road nasal (n=5), TT handlebar nasal (n=5), TT TTbar nasal (n=15), TT TTbar oral (n=6). Full Bland-Altman analysis, Lin CCC, Passing-Bablok regression, and Cohen's d (Hedges-corrected) were performed per condition.Results. Global RR accuracy: bias=+0.300 bpm, LoA -1.08;1.67, PE=10.2%, CCC=0.994. TT bike conditions: PE=5.3%, 96% within +/-1 bpm. Breathing route on TT bar is a large effect (d=1.06, +8.7 AU/L, RR-matched). A posture gradient emerges under nasal breathing: ergocycle 72.8 position > bicycle type > intensity) provides condition-specific Tidal/VT conversion coefficients. All results are individual (n=1 athlete); population generalisation is not claimed.VST Research Series — Study 3 of 3.

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