Glossary
Grade-adjusted pace
Your pace on a hill converted to the flat-road pace of equal effort. A 5% climb usually costs 30-45 s/km (48-72 s/mi).
What it is
A translation. It takes the pace you actually ran on a slope and reports the flat pace that would have cost the same energy.
The conversion rests on measured energy costs of running at different gradients. Minetti and colleagues published the reference curve in 2002, from treadmill work across slopes from -45% to +45%.
| Gradient | Rough pace cost per km | Per mile |
|---|---|---|
| +2% | 12-18 s | 19-29 s |
| +5% | 30-45 s | 48-72 s |
| +10% | 70-95 s | 113-153 s |
| -5% | 10-20 s faster | 16-32 s faster |
What it is not
It is not your race pace on that course. Adjusted pace tells you about effort, not about the clock. A hilly marathon is still slower.
It is also not exact. Downhill running has a limit past which braking costs more than gravity gives, and the curve flattens.
What moves it
- The gradient itself. The whole input.
- Elevation data quality. Barometric readings beat satellite ones.
- Where the slope sits. A climb late in a run costs more than the model says.
- Your downhill technique. The model assumes you use the descent.
When to ignore it
Ignore it on trails and technical ground. Footing costs energy the gradient model knows nothing about.
Ignore it for pacing a race. Run the climbs on effort, and judge the day on finish time.
Sources
- Minetti AE et al. Energy cost of walking and running at extreme uphill and downhill slopes. J Appl Physiol 93(3):1039-1046, 2002 primary
- Vernillo G et al. Biomechanics and physiology of uphill and downhill running. Sports Med 47(4):615-629, 2017 primary
- Jones AM, Doust JH. A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. J Sports Sci 14(4):321-327, 1996 primary