The USA Pro Challenge started in Aspen on Monday. Over 120 cyclists from around the world competed in a circuit race between Aspen and Snowmass.
Colorado Public Radio talked to race announcer Phil Liggett. He said the riders were worried about the opening day because aspen is already at altitude.
"The guys who want to win this race…the race is over 7 days, a total of just over 800 miles in a week, it’s a tough week for them…but they know that a mistake on the first day and they may as well not bother with the rest of the week," Leggit told CPR.