Add Yahoo as a preferred source to see more of our stories on Google. Scientists have long hypothesized about a theoretical limit to human energy use. Yet elite endurance athletes are constantly ...

Scientists provide proof that ultramarathon athletes’ red blood cells become less flexible after a long race, potentially reducing their ability to efficiently carry oxygen ...

Paul Johnson, a veteran and ultra runner, is known for his running adventures, like running across America and beating world running records in places like Antarctica. Now he's on his way to beating ...

Add Yahoo as a preferred source to see more of our stories on Google. United States ultramarathon runner Courtney Dauwalter runs through the mountains near Twin Lakes, Colorado. Dauwalter sits at the ...

From muscle fibers to mental grit, here’s the science behind why some bodies can endure ultramarathons, while others hit the wall far sooner. Ultramarathons sit at the far edge of what the human body ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. It's the original 100-miler, but that's not the only thing that makes this iconic trail race ...

My roommate and I had the luck of choosing the exact same trail as the Santa Barbara Nine Trails Endurance Run on the same hot Saturday morning. We were headed in the opposite direction, and only ...

I am not a natural-born runner, but I ran my first ultramarathon just before turning 50. Here’s how I finally got consistent ...

Ultra runner Tim Kacprzak started 2026 by running 1 kilometre, and has added a kilometre each day in his attempt to win the ...

Backyard ultras already have a reputation for being unconventional, but Frankie’s Vertical Backyard Ultra is taking things a ...

A 60-year-old Michigan woman died Friday four hours into the Hardrock 100, a 100-mile run through the San Juan Mountains. Elaine Stypula of Farmington Hills, Michigan, was pronounced dead by the San ...