Run Analyzer

A GPS watch records your position, heart rate, and cadence several times per second. That raw data contains more information than most platforms surface. Per-kilometer splits show where you sped up or faded. Heart rate zone distribution reveals whether you ran easy or pushed into threshold. Grade-adjusted pace strips out elevation effects so you can compare effort across flat and hilly terrain.

GPS accuracy varies. Tree cover, tall buildings, and even cloud cover introduce noise into position data. Your watch might report 10.05 km for a certified 10K course. Elevation data from barometric altimeters is generally accurate to 1-3 meters, but satellite-derived elevation can be off by 10-30 meters.

Heart rate lag is real. Your heart rate takes 30-60 seconds to respond to a pace change. The first few hundred meters of a tempo interval will show Zone 2 heart rate even though your effort is Zone 4. Zone breakdown percentages are accurate over a full run but can mislead for short intervals.

The Pace It app syncs with Strava, Garmin, and Apple Watch to automatically analyze every run. It tracks your pace-at-effort trends over weeks and months, showing how your fitness evolves. The app uses your actual data to set adaptive pace targets that match your current fitness.