Ashley Paulson Just Ran 100 Miles on a Treadmill in Under 13 Hours
Ashley Paulson set a new women's 100-mile treadmill world record at the Boston Marathon Expo, clocking a mind-bending 12:47:10 surrounded by cheering crowds.
· 4 min read · Athletics News
Most runners complain about the "dreadmill" after 45 minutes of staring at the same gym wall.
Ashley Paulson just stared at the console of a treadmill for nearly 13 hours and set a world record in the process. During the bustling 2026 Boston Marathon Expo, Paulson stepped onto a motorized belt and ran 100 miles in a staggering 12 hours, 47 minutes, and 10 seconds.
Let's put that math into perspective. She averaged a 7:40 per mile pace. For 100 miles. Without ever moving forward.
The Mental Toll of the Treadmill Ultra
Running a 100-mile ultramarathon outdoors is brutal on the body. You have to navigate rocks, roots, elevation changes, and unpredictable weather. But you get the benefit of changing scenery, fresh air, and natural micro-breaks when you slow down for a technical descent or a steep climb.
Running 100 miles on a treadmill removes the physical obstacles and replaces them with an intense psychological test. The belt never stops unless you hit the button. Every footfall is identical, creating a repetitive strain on the exact same muscles and joints for over 80,000 steps.
Paulson didn't just survive the mental grind. She thrived in it. Surrounded by thousands of runners picking up their bibs for the Boston Marathon, she turned an isolated indoor workout into a spectator sport. The energy of the expo crowd clearly fueled her late-stage push, but holding a 7:40 pace past the 80-mile mark requires a level of focus that very few athletes possess.
Fueling on a Moving Belt
One of the few advantages of a treadmill ultra is the logistics. You do not need to wait for the next aid station to grab a gel.
Paulson's crew was able to hand her fluids, ice, and nutrition exactly when she needed them. This controlled environment allowed her to execute a flawless fueling strategy. In a typical outdoor ultra, a missed aid station or an upset stomach from drinking warm water out of a soft flask can end your day. Here, the temperature was controlled, and the fuel was always an arm's reach away.
But eating solid food while running 7:40 pace on a moving belt is a skill of its own. It requires a trained gut and the coordination to not trip over your own feet while grabbing a cup of electrolytes.
Why This Matters for Everyday Runners
You probably have no desire to run a 100-miler on a treadmill. But Paulson's record proves something important about indoor training.
When the weather is terrible, or you have to watch your kids, or it's dark outside, the treadmill is a valid and powerful tool. Too many runners skip workouts because they hate the treadmill. Paulson showed us that the machine is not the enemy. It is just a different surface.
If you are stuck inside for your next run, you can use our [pace calculator](/tools) to figure out the exact speed you need to set the treadmill belt to hit your interval targets.
And the next time you feel like complaining that your 5-mile treadmill run is boring, just remember someone ran 95 miles further on that exact same belt.
*Thinking about taking your training to the next level? Map out your next training block with our [run planner](/runs) and stop letting bad weather ruin your weekly mileage.*