What is W' in sports science?

W' (W-prime) is the finite anaerobic work capacity above critical power, typically 10–25 kJ for cyclists. Once depleted, the athlete must drop below CP to allow reconstitution. W' is depleted at rate (P - CP) W and reconstituted exponentially below CP.

How does W' reconstitution work during exercise?

W' reconstitutes exponentially when power drops below CP, with a time constant (τ) of ~400 seconds. After a hard 1-minute effort expending 10 kJ of W', it takes ~5 minutes below CP to recover ~80% of W'.

W' (W-Prime) Energy Reserve Calculator

Model your W' depletion and reconstitution during variable-intensity efforts. Predict when your anaerobic reserve will be exhausted during a race or workout.

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Distance covered in 12 minutes (meters)

🏅 Sports Note: These calculators provide estimates based on population data and validated formulas. Individual results vary by physiology, training level, and testing conditions. Consult a qualified coach or sports scientist for personalized guidance.

How to Use

Enter the values for the scenario you are assessing. Model your W' depletion and reconstitution during variable-intensity efforts. Predict when your anaerobic reserve will be exhausted during a race or workout. Use the w' energy reserve result to inform your calculation.

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W' (W-Prime) Energy Reserve Calculator

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Frequently Asked Questions

What is W' in sports science?

How does W' reconstitution work during exercise?