Anatomy of a VST Monitoring in WorldTour Cycling
- May 16
- 5 min read
Anatomy of a VST Monitoring in WorldTour Cycling
What are we looking for when we watch an athlete breathe for 35 minutes of effort?
HNS Performance case study — WorldTour Pro athlete, 60 kg, 21 years — Session of May 8, 2026
Before diving into the numbers of this session, I want to explain what a VST monitoring is.
Because it's a category of evaluation that resembles neither a classical laboratory test, nor a standard training follow-up.
And because the reading that follows only makes sense if we share the starting framework.
What a VST monitoring is
VST stands for Ventilatory Strategies Training.
It's a conceptual and operational framework I've been developing for several years.
It considers the ventilatory pattern — respiratory frequency, tidal volume, their product, their temporal geometry — not as an accessory signal of effort, but as a central determinant of performance.
And as a trainable lever, on the same footing as muscle power or capillarization.
A VST monitoring, concretely, is an instrumented session in which the athlete executes a standardized protocol while several signals are simultaneously captured:
— expired gases (VO₂, VCO₂, FeO₂, ventilatory equivalent for oxygen)
— ventilatory pattern (respiratory frequency, tidal volume, total ventilation)
— compartmental muscle perfusion, via NIRS on quadriceps and arm
— blood hemodynamics, at several timepoints
— morning spirometry (FEV1, FEV6, inspiratory S-Index)
Seven to eight signals co-recorded.
Cross-analyzed.
Second by second.
What we're looking for
Three questions structure every VST reading.
First question: where are this athlete's physiological locks?
The oxygen supply system is a six-link chain: alveolar ventilation, alveolar-capillary diffusion, arterial transport, capillary-muscle diffusion, intramuscular diffusion, mitochondrial oxidative phosphorylation.
Performance is limited by the weakest link.
The role of monitoring is to identify which one, through convergence of coherent signatures rather than through an isolated marker.
Second question: is the ventilatory pattern an asset, a neutral, or an aggravating factor?
An athlete ventilating at high respiratory frequency and low tidal volume at VT2 squanders oxygen in alveolar dead space.
The same athlete shifted to low respiratory frequency and high tidal volume at the same power typically saves 10 to 15 % of total ventilation for the same oxygen consumption.
Third question: where is this athlete today relative to themselves?
Monitoring isn't only meant to profile.
It also serves to date a daily state within the long dynamic of the season.
To objectify subclinical fatigue before it becomes visible.
To validate that a training protocol is producing the expected adaptations.
What we read — the HNS proprietary indices
This reading relies on proprietary indices I develop within the HNS framework.
ICIF (FIV / FEV1)
Reads the inspiratory-expiratory volumetric imbalance from morning spirometry.
Separates inspiratory-dominant profiles from expiratory-dominant profiles.
ECFI (PEmax / FEV1)
Distinguishes a drop in expiratory capacity of muscular origin — maximal expiratory pressure drops in parallel with FEV1 — from a drop of bronchial origin, in which maximal expiratory pressure remains stable.
ICP SmO₂ (SmO₂ Quads / SmO₂ Arm)
Reads compartmental perfusion between the locomotor effector and a reference non-locomotor compartment.
Decreases with power through preferential extraction by the quadriceps.
Rises at end of effort when the metaboreflex redistributes cardiac output.
IPV (Tv / Rf) and IPV Norm
Sign the very geometry of the ventilatory pattern.
Constitute the direct marker of VST strategy application.
The framework of the 3 discriminants and the triple lock
Alongside these indices, the reading mobilizes three physiological discriminants:
— D1 ventilatory — separates upstream supply limitations from efficiency limitations
— D2 muscular — characterizes peripheral utilization of type II fibers
— D3 VO₂max output — compares the observed value to the WorldTour benchmark
At VO₂max, I look for a simultaneous triple lock:
— systemic extraction between 80 and 85 %
— difference in fraction of expired versus inspired oxygen of at least 5 %
— SmO₂ quadriceps dropping to 10 or 15 %
When all three converge at the same time, we're in the presence of a true physiological peak.
And not a transient kinetics.
Why this specific session is interesting
The May 8, 2026 session documents a 21-year-old WorldTour athlete at a doubly loaded moment.
Return of stimulus after a brief break following the spring classics — three days off followed by four days of progressive resumption.
And 48 hours before departure for a three-week altitude camp at Sierra Nevada, at 2,300 meters.
Two transient states overlap.
Two different questions arise.
And the session must answer both simultaneously.
On the re-entry side: is the machine working?
On the pre-altitude side: which ventilatory targets should structure the work at weighted altitude?
The protocol
Five structured repetitions of the following block:
— 30 seconds at 500 W
— 30 seconds at 420 W
— 2 minutes at 380 W
— 1 minute at 420 W
— 6 minutes at 100 W in active recovery
This protocol is designed to answer both questions in a single pass.
The 500 W peak tests transient activation kinetics and the VST "start during" strategy applied to the initial transition.
The 2-minute block at 380 W probes time-in-zone at VO₂max and the type I fiber switch signature on the second minute.
The 1-minute block at 420 W documents supra-VT2 engagement density.
The 6 minutes at 100 W of active recovery allow quantifying the AFTER effect.
This AFTER effect is the free mitochondrial load I've been working to formalize since the HNS VO₂ kinetics study — an oxygen consumption that remains elevated while external power has abruptly dropped.
Opening a window of mitochondrial stimulation at reduced mechanical cost.
What the report deploys
The full report is divided into three parts.
Part 1 — Analytical reading of the session.
Progressive calibration 240 → 400 W stage by stage.
Longitudinal comparison to February and March 2026 sessions at identical powers.
Second-by-second kinetics on critical blocks.
Inter-series drift over the last twenty seconds of each block.
Reading of the three documented locks.
Part 2 — Altitude ventilatory performance profile.
Construction of iRf and iTv targets zone by zone, at three altitudes: sea-level, 1,500 meters, 2,000 meters.
Watts weighting grounded in the literature.
Progressive altitude sliding logic.
Part 3 — Work plan toward post-camp target races.
Complete molecular argumentation on PGC-1α and HIF-1α signaling pathways.
Concrete cellular targets.
Expected altitude adaptation timeline.
RSH modality with quantitative parameters.
Technical annex.
THb stability over the 5 series.
Inter-series correlations of the SmO₂ pattern.
HNS methodology for the VO₂max time-to-zone criterion with literature justification.
Document posture
Everything is sourced.
Everything is hierarchized by evidence level — HIGH, INTERMEDIATE, or LOW-EXPLORATORY.
Mechanistic hypotheses labeled.
Analytical limits made explicit section by section.
Fully anonymized document.
100 % robust scientific defensive posture: no fabricated reference figures, no conclusions beyond the data.
To go further, the full PDF is available for download — English.
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