Tools
Check whether you're pushing too hard uphill. Convert trail pace into a flat-ground effort equivalent.
If you're running 6:00/km on a 10% climb, how hard are you really working? GAP answers that question. It translates your pace on any gradient into the equivalent effort on flat ground, so you can see whether you're overreaching or still have room to move.
Going out too hard on climbs is one of the most common pacing mistakes in trail and mountain racing. By the time your legs tell you it was too much, the damage is already done. GAP gives you an objective pacing anchor.
The calculator uses the Minetti (2002) energy-cost model – a polynomial describing how metabolic cost changes with gradient, validated in laboratory settings from -45% to +45%.
The calculator defaults to a practical adjustment. It is a Strava-style curve derived from millions of running activities. On uphills it matches the Minetti model, but it caps the downhill benefit so the effort multiplier reflects what runners actually convert to speed. Braking forces, eccentric muscle damage, and footing limit downhill pace long before metabolism does. Switch to the pure Minetti model below if you prefer the metabolic cost over the practical pace equivalent.
Caps downhill benefit to match what runners can actually convert to speed. Based on Strava's 2017 data-driven model.
Your 06:30 min/km on this gradient is equivalent to 04:18 min/km on flat ground.
If your GAP comes out much faster than your usual threshold pace on flat ground, the climb is too aggressive. You are working above threshold and will pay for it later, especially in the second half of a race. Back off until GAP sits around your flat threshold pace or slightly slower. As a practical anchor: if your flat 10K pace is 5:00/km, your uphill GAP should usually land around 5:00–5:30/km, not faster.
On steep descents, the model reflects the rising cost of eccentric braking. If the result feels odd, technique and surface are probably limiting speed before pure fitness does.
GAP models metabolic cost. It does not account for altitude, heat, fatigue, or individual biomechanics. If heart rate and GAP tell different stories, use both, but let heart rate win on the day.
How much harder or easier is each gradient than flat ground? Based on the Minetti (2002) model, shown here for a reference pace of 6:00/km.
| Gradient | Practical | Minetti | ||
|---|---|---|---|---|
| Effort | GAP at 6:00/km | Effort | GAP at 6:00/km | |
| +5% | 1.30x | 04:37 | 1.30x | 04:37 |
| +10% | 1.66x | 03:37 | 1.66x | 03:37 |
| +15% | 2.06x | 02:55 | 2.06x | 02:55 |
| +20% | 2.50x | 02:24 | 2.50x | 02:24 |
| -5% | 0.90x | 06:38 | 0.76x | 07:52 |
| -10% | 0.88x | 06:48 | 0.60x | 10:02 |
| -15% | 0.93x | 06:26 | 0.51x | 11:46 |
The practical model (Strava-style) caps downhill benefit around -9%. The Minetti model keeps amplifying the metabolic saving on descents, which rarely translates to proportional speed gains.
Training plans
You know your grade-adjusted effort. A personalized plan puts those numbers to work across weeks of structured training.
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Real-time pace, elevation, and navigation for trail pacing decisions.
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