Keep In Band, the heart-rate coach that stays offline

Field notes

The training model centers on a target heart-rate band rather than pace, with the page presenting pace as vulnerable to wind, hills, and fatigue. It says the app can associate difficult sections with terrain, surface, or fatigue on a kilometre-by-kilometre map, then time recovery after the session. The proposed coach learns locally on the iPhone and is meant to withhold advice unless it beats a conventional formula on workouts it has not seen.