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Quant Library · The athlete · Athletics

Carbohydrate Limit and the Wall

The fastest pace the carbohydrate on board can actually pay for.

Rapoport's arithmetic: the cost of the distance, the share of it that must come from carbohydrate at a given intensity, and what the legs, the liver and the feed zone can supply.

Inputs

What it takes

3
NameTypeUnitsWhere it comes from
mass, VO2maxfloatskg, ml/kg/minthe athlete
leg muscle fraction, glycogen density optionalfloatsfraction, mmol/kgmeasurement or literature defaults
intake optionalfloatg/hourthe plan
Outputs

What it gives back

3
NameTypeUnitsNotes
limit intensityfloatfraction of VO2max
predicted timefloath:mm:ss
need and supply curvesarraysgrams
Method

How it works

  1. Cost the race at about 1 kcal per kg per km.
  2. 2 further steps in the licensed specification
Assumptions
  • Steady pace, and gut tolerance for the intake you plan. Both are the athlete's problem more often than the model's.
Limits
  • It gives a ceiling, not a prediction: plenty of runners slow for reasons that have nothing to do with glycogen.
Validation

What it was measured at

ok

Solved now, for a 62 kg runner at VO₂max 70.

Muscle glycogen on board305 gplus about 90 g in the liver
Eating nothingwall at 76% of VO₂maxa 2:46:34 marathon
Eating 60 g an hourlimit at 90%a 2:20:39 marathon
What it gives youa ceiling, not a predictionrunners slow for other reasons too
In the package
  • The full specification: inputs, method, assumptions and limits
  • The validation panel as measured on the day of purchase
  • A reference implementation extracted from the running source
  • Perpetual commercial use for one entity

Reference modules:

  • 1 module(s), named in the licensed specification and shipped in the package
Read this before you buy. The platform's own walk-forward tests say the closing line forecasts football better than these models do. What they give you is a coherent price for every market and match, before the market opens, with the band and the working attached. Any model here that has been beaten by something simpler says so in its limits, and the validation panel above is generated from the platform's result files rather than typed in.