Triathlon

The ultimate endurance test: 1.5km swim, 40km bike, 10km run, in a mass start (60+ athletes). Drafting on the bike is legal (creating large bike packs), the "transition" (swim to bike to run) is a fourth discipline, and the "blue card" (penalty for drafting too close) is a 10-second stop-and-go, making it 1 hour 45 minutes of non-stop, multi-discipline suffering.