Why Your Ascent Never Matches Your Watch
Ascent is a choice, not a measurement, so two honest tools reading one file will disagree. This page gives both usual choices: the raw sum of every upward step, and a 5 m threshold figure that counts a rise only once the track climbs 5 m above its last low point. On the sample route: near 750 m against near 660 m, same 10.5 km.
The apps you compare against choose too, and rarely say which:
- Strava calls gain an estimate and says changes "may not be enough to pass a threshold that we use" — without publishing that threshold.
- Garmin uses the device barometer when there is one and its own Digital Elevation Model when there is not; for devices without a barometer it warns that a gap against another platform can come from "a different elevation dataset or calculation method".
- Race organisers publish one number with no method attached.
So use the threshold figure against a watch or a race profile, because it counts the way they do; a raw sum far above it means noisy elevation. If a Garmin activity looks wrong at source, Change Elevation Source sits under the gear icon on the Garmin Connect website, not the app.
Reading the Profile as a Pace Plan
Climbing costs more time than the matching descent gives back, which is why a profile is worth reading before a race. This table converts grade into pace with the same model as our grade-adjusted pace tool, at a 5:00/km base.
| Grade | Pace effect | At 5:00/km |
|---|---|---|
| 3% up | 7.5% slower | +23 s/km |
| 6% up | 15% slower | +45 s/km |
| 10% up | 25% slower | +1:15 /km |
| 15% up | 42.5% slower | +2:08 /km |
| 3% down | 4.5% faster | −14 s/km |
| 6% down | 9% faster | −27 s/km |
| 10% down | 15% faster | −45 s/km |
A 6% climb costs about 45 seconds per kilometre; the matching descent returns about 27. A rolling course is therefore slower than a flat one of the same distance, even ending where it started.
Pace the effort and let the watch move. Drag across a climb and you get that section alone — length, gain, average and steepest grade — enough to set a slower target and treat the descent as recovery. Where a grade breaks your stride, a fast walk often costs little; test that in training, not on race day. The percentages are RunDida's engineering approximation, not a research finding; hill pacing strategy turns them into segment targets.
What Is Actually Inside a GPX File
The format demands very little. Latitude and longitude are required on every point; elevation and time are optional, and time is stored in Coordinated Universal Time, not your local clock. Everything beyond position is an optional extension.
- Tracks and routes differ. A track is an ordered list of points describing a path; a route is a planned list of turn points with no timestamps, so its time columns stay empty.
- Heart rate, cadence and temperature are extensions. Garmin's TrackPointExtension schema defines them as beats per minute, revolutions per minute and degrees Celsius — revolutions is why a running cadence often reads 85 rather than 170.
- Waypoints are your aid stations. The specification calls one a point of interest or named feature on a map; this page projects each onto its distance along the course.
Export with Export GPX in a Strava activity's ellipses menu on the Strava website, or the gear icon on a Garmin Connect activity. Another athlete's Strava export arrives stripped of performance data: their course, nothing about their run. Your file never leaves the browser, though the map behind it is not local — tiles come from OpenStreetMap and OpenTopoMap servers, which see the area you view but never the file.