wbal.io — W′ Balance Analyser

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Drag & drop a .fit or .csv file here, or browse

Critical power model

CP W W′ J

Don't know your CP and W′? Determine them for free →

Recovery model

τ = 546·e^−0.01·DCP + 316

Read-only — Skiba et al. 2012

τ = 2287·DCP^−0.688

Read-only — Bartram et al.

τ = 789·DCP^−0.468

Read-only — Pugh et al. 2022, international level

τ = 1883·DCP^−0.487

Read-only — Pugh et al. 2022, national level

τ = 5184·DCP^−0.700

Read-only — Pugh et al. 2022, regional level

τ = A · DCP^−B

A B

τ = A1·e^−B1·DCP + A2·e^−B2·DCP

A1 B1 A2 B2

Determine Critical Power & W′ — Free

Fit your personal power-duration curve from maximal effort tests. Enter results manually or upload power files. Minimum two tests at different durations — ideally one short (3–5 min) and one longer (10–20 min). Read the full guide →

Add tests

Enter the label, duration (min : sec), and mean power for each maximal all-out effort test.

Label	Duration (min : sec)	Mean power (W)

Tests to fit

Label	Duration	Mean power (W)	Work (kJ)

Fitted values

Test	Duration	Measured (W)	Model (W)	Residual (W)

Power-duration curve

Test parameters

Upload one file per recovery trial. Designate the DCP 0 trial (recovery at CP — no reconstitution) to calibrate W′_ERG. Recovery trials are fitted so W′bal at exhaustion equals W′_ERG, not zero.

CP W W′ J

Recovery trial files

Minimum 3 trials required. Use different recovery intensities to constrain both model parameters.

Drag & drop trial files, or browse

Detected trial structure

File	Role	Recovery power (W)	DCP (W)	Recovery duration (s)	TTE power (W)	TTE duration (s)	Status

Model to fit

Fitted constants

Trial	DCP (W)	W′bal at exhaustion	Deviation from W′ERG