Retirement from pro road racing has opened new doors for Lance Armstrong. This fall, the former roadie and seven-time Tour de France winner tackled the New York City marathon, and next August, he'll try out the Leadville Trail 100, a 100 mile mountain bike race in Leadville, Colorado.

Race director Ken Chlouber confirmed the race was on Armstrong's schedule, which now consists of only a few races per year. "This is huge for Leadville," Chlouber told the Leadville Chronicle. He added that the race was well suited for Armstrong, who is known for surmounting tough personal obstacles like cancer.

The Leadville 100 began in 1983 and covers a 100-mile course through the Sawatch mountains. It features 15,600 feet of climbing and descending. The race is notoriously challenging because the entire course is at a high altitude. The lowest point is 9,200 feet, and the highest point is 12,620 feet. The race is so popular that a lottery is used to dole out the available slots. About 500-600 of the 750 starters finish the race annually.

It won't be Armstrong's first appearance off road, but it will be the first time he races an endurance mountain bike event. If he has time to train, the Tour de France winner could challenge for the win.