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Ultramarathon

Competitors run in the 2013 Badwater Ultramarathon in Death Valley National Park, California. The 135-mile (217 km) race, which bills itself as the world's toughest foot race, goes from Death Valley to Mt. Whitney, California. Temperatures can reach 130 d

Ultrarunning tests the outer boundaries of human endurance, but doctors say it’s still safe

Science

First there was the Triathlon. Then the Ironman and Ultramarathon. Athletes are pushing themselves to their absolute limits, but despite some things to watch watch for, doctors think the sport is still safe.