Metabolic Test (VO2max + thresholds from a FIT upload)

What this is

The Metabolic Test tool parses a ramp or step-test FIT (or .fit.gz) and produces:

• VT1 (first ventilatory threshold) — power and HR.
• VT2 (second ventilatory threshold) — power and HR.
• VO2max — peak measured.
• Peak power, peak HR.
• Per-interval breakdown with energy + gross efficiency estimates from the _augment_intervals_with_energy helper.

URL: /admin/metabolic-test/.

Important: this is NOT a seeded AssessmentType

Unlike the CSS test, CdA field test, CP test, sweat rate test, RSI test, and the two Lactate tests — all of which are seeded AssessmentType rows with their own protocol_steps and expected_inputs — the metabolic test does not create an Assessment row. When you click Save:

• A CalculatorResult row is written, with calculator='metabolic_test', the parsed report stored in the outputs JSON, and the uploaded FIT linked.
• MetricHistory rows are written for VT1 power and VO2max so the athlete's metric history reflects the new numbers.

If you're looking for a metabolic test in the seeded AssessmentTypes, there isn't one — the FIT-based metabolic flow is its own ingest path. For reference, related seeded AssessmentTypes that DO exist on the bike / run side are VO2max Bike Test and VO2max Run Test (paper-driven, no FIT parser).

What the upload accepts

• .fit or .fit.gz.
• Test type auto-detected as ramp (continuous power increment) or acyclic / step (discrete plateaus).
• For ramp tests the parser sweeps the gradient to find VT1 and VT2 inflection points.
• For step tests, intervals are detected by power discontinuities and averages are computed per step.

What the report shows

• Test classification (ramp / acyclic).
• VT1, VT2, VO2max with their power and HR pairings.
• Peak power and peak HR.
• A per-interval table — only useful for step tests.
• Gross efficiency estimates per interval where O2 cost can be derived from power + ventilation data.

How to run a metabolic test that this tool can parse

• Ramp test — most common. Start at low wattage, increase by a fixed step (e.g. 20 W / min or 25 W / 2 min) until failure. The continuous incremental load lets the parser fit the VT inflection points.
• Step test — 4-6 minute plateaus at increasing power. Useful when paired with a metabolic cart for breath-by- breath data, but the platform's parser works on the FIT power record alone.

For lab-grade interpretation, pair the FIT-based result with a calibrated metabolic cart's gas-exchange readout. The Hub's estimates are noisy compared to lab VT thresholds and should be treated as a field-grade reference, not as a substitute for cart data.

When to use this vs other tools

• Use this tool when you have a FIT from a structured ramp / step test and want quick threshold + VO2max numbers.
• Use the CP test if you want CP and W' — different physiological anchors.
• Use the CSS test for swim threshold — this tool is bike/run only.

See also: Assessment model overview, Yousuli bike zones.