Settings → Battery → Battery saver (off by default). You can also turn it on during the race in the live controls.
It works by battery level, with Kicks in below set between 5% and 80% (default 30%):
Above the threshold: full GPS accuracy, as usual.
Below the threshold: lower accuracy. On iPhone a position every ~50 m, on Android every 15 seconds without the GPS chip (wifi/cell). Positions are sent every 2 minutes.
Very low battery (half the threshold, at most 15%) and nobody watching: even sparser, ~100 m on iPhone or 30 seconds on Android.
When a cheer is due, full accuracy comes back so it plays at the right spot.