Effort & pacing
Training paces
Every training pace, from Easy to Repetition, derived from one number: your VDOT.
Daniels' VDOT is an empirical estimator that assumes average running economy, so individual economy (which varies 10-15%) means your ideal paces may run slightly faster or slower.
Every one of your training paces comes from a single number, your VDOT (see the Aerobic index). Each type of run asks your body to work at a chosen fraction of your VO2 max, and we turn that oxygen demand back into a pace by inverting Daniels' oxygen-cost curve.
Five families, five jobs
Daniels sorts training into five kinds of running, each aimed at a different band of your VO2 max and each training a different system. Easy running builds the aerobic base. Marathon pace rehearses race-specific efficiency. Threshold work raises the lactate threshold. Interval running maximizes VO2 max itself. Repetition running sharpens economy and raw speed, and is the one family that is not about the aerobic engine at all.
| Run type | % VO2 max | What it trains |
|---|---|---|
| Easy / recovery | 63-74% | Aerobic base: mitochondria, capillaries, stroke volume |
| Marathon | 79-84% | Race-specific efficiency at goal pace |
| Threshold | 86-88% | Raises the lactate threshold |
| Interval (VO2 max) | 95-100% | Maximizes VO2 max |
| Repetition | 103-110% | Economy and speed (not aerobic) |
From oxygen demand to pace
Daniels measured how much oxygen it takes to run at a given speed and fit it to a curve (v is velocity in metres per minute):
VO2 = −4.60 + 0.182258v + 0.000104v2To find the pace for a family, we take its target fraction of your VO2 max as the oxygen demand, then solve this curve for the velocity that costs exactly that much. Faster families ask for more oxygen, so the curve hands back a faster velocity.
Worked example
An athlete with a VDOT of 50 (roughly equivalent to a VO2 max near 50 ml/kg/min) wants a threshold pace. Threshold work targets about 88% of VO2 max:
- Target oxygen demand: 0.88 × 50 = 44 ml/kg/min
- Solve the oxygen-cost curve for the velocity that costs 44: about 235 m/min
That velocity works out to a threshold pace of approximately 4:15/km.
Treat them as starting points
VDOT is an empirical estimator fit to pooled race data, and it assumes an average running economy. Individual economy varies by 10-15%, so your ideal paces may sit slightly faster or slower than the table suggests. These paces are excellent starting points, not exact prescriptions. Evidence tier: empirical estimator.