Sure, Usain Bolt can run 200 meters faster than anyone else in the world, but let’s see him do it on a broken leg.

Manteo Mitchell did exactly that when his left fibula cracked midway through his opening leg of the men’s 4x400 relay. He didn’t stop, and didn’t even slow down much, finishing his leg and helping the U.S. to a second-place finish while qualifying for Friday’s final.

Although he told reporters immediately after the race that he merely had a cramp, X-rays later revealed the fracture.

“Three days ago I was going up the stairs and I kind of missed one and landed awkwardly,” Mitchell said in a release from USA Track and Field. “I got treatment and I was fine. I did workouts, and when I warmed up today I felt really well. I felt I could go 44 (seconds)-low. I got out pretty slow, but I picked it up and when I got to the 100-meter mark it felt weird. I was thinking I just didn’t feel right.

“As soon as I took the first step past the 200-meter mark, I felt it break. I heard it. I even put out a little war cry, but the crowd was so loud you couldn’t hear it. I wanted to just lie down. It felt like somebody literally just snapped my leg in half.’’

Mitchell said that seeing the next American runner, Josh Mance, motioning for the baton handoff gave him the lift he needed to keep running hard. “I didn’t want to let those three guys down, or the team down, so I just ran on it,’’ he said. “It hurt so bad. I’m pretty amazed that I still split 45 seconds on a broken leg.”

This has been a tough Olympics for America in the 400-meter events. LaShawn Merritt, the 2008 gold medalist, pulled up with a hamstring strain in a heat and the U.S. wound up not having a runner in the 400 final for the first time ever. Now Mitchell, who made the relay pool after finishing fifth in the 400 at the U.S. trials, is out, too.

The U.S. has yet to announce its relay team for the final.