Apps like MapMyRun rely on GPS, which can drift:
- Tall buildings, trees, or tunnels = signal bounce
- Turns get “rounded out” instead of sharp
- Small errors stack up over 13+ miles
Even a tiny 1–2% error can add 0.1–0.3 miles.
The Run Madtown Twilight 5K, 10K and Half Marathon courses are all USATF Certified.