What is GAP?
Grade Adjusted Pace (GAP) converts your pace on hills to an equivalent flat-ground pace. It helps you understand the true effort of running uphill or downhill by accounting for gradient.
Why GAP Matters
When you run uphill at 6:00/km, you’re working much harder than running 6:00/km on flat ground. GAP answers the question: “If I’m running 6:00/km up a 5% grade, what flat pace does that effort equal?”
Real Examples
- 6:00/km at +5% grade ≈ 5:15/km flat effort (you’re working harder than your watch shows)
- 6:00/km at -5% grade ≈ 7:00/km flat effort (easier than it appears)
- 5:00/km at +10% grade ≈ 4:00/km flat effort (significantly harder)
When to Use GAP
Trail Running & Hill Training
- Compare workouts done on different terrain
- Understand your true effort on mountain trails
- Gauge fitness improvements across varied routes
Race Planning
- Predict finish times for hilly courses
- Adjust pacing strategy based on elevation profile
- Set realistic goals for mountain races
Training Zones
- Maintain consistent effort on hills (use GAP, not raw pace)
- Avoid going too hard uphill or too easy downhill
- Better recovery management
How Gradient Affects Pace
- Uphill (+): Every 1% grade significantly increases effort
- Steep uphills (>8%): Effort increases exponentially
- Downhill (-): Reduces effort, but not linearly
- Steep downhills: Limited benefit due to braking mechanics
Common Mistakes
- Chasing pace uphill: Ignore your watch pace on hills—focus on effort or GAP
- Running too hard downhill: Negative grades feel easy but cause muscle damage
- Comparing flat vs hilly runs: Use GAP to make fair comparisons
Training Applications
- Easy runs on hills: Use GAP to stay in your easy zone (don’t push to match flat pace)
- Tempo efforts: Adjust target pace based on terrain
- Long runs: Calculate equivalent effort for hilly routes
- Recovery: Understand why hilly “easy” runs feel harder
Quick Reference
Pro Tip: Most GPS watches (Garmin, Coros, Suunto) can display GAP as a data field during your run. This helps you maintain consistent effort regardless of terrain.
Common Conversions
For quick mental math on the trails:
- +5% grade: Add ~30-45 seconds per km to your flat pace
- +10% grade: Add ~1:15-1:30 per km
- -5% grade: Subtract ~30-40 seconds per km
Resources
Learn more about running science and training: