The fourth running of Colorado’s seven-day USA Pro Challenge cycling stage race kicks off today in Aspen. Following the success of last year’s start, the town will once again host a circuit course stage for the 550-mile race’s opening day. With a starting elevation of 7,908 feet, riders will have to acclimate early. Last year, 2013 Tour de France winner Chris Froome’s Team Sky struggled from the get-go; he later admitted that the team may have arrived too late to properly acclimate to the altitude. Beyond the challenges of racing high above sea level, the Aspen/Snowmass circuit course will be a fast-paced start to the race. The 65-mile course includes three 22-mile laps between Aspen and Snowmass. Each lap will have riders fighting 2,300 feet of elevation gain with little time to recover. The steep trek up from Aspen to Snowmass will be a challenge early, and the short laps could see another tight peloton cross the finish line at the end of day one. Among top competitors this year, BMC team rider Tejay van Garderen of Aspen will be looking to set the tone early in hopes of repeating as the race’s overall winner. Van Garderen is looking strong once again coming off a fifth-place finish at this year’s Tour de France. After finishing on top of the podium in the Tour of Utah earlier this month, Boulder’s Tom Danielson (Garmin-Sharp) will also be looking to contend. Danielson finished last year’s Pro Challenge third in the general classification (GC) standings. While no one is likely to jump too far out in front after day one, it will be interesting to see if any riders show early signs of altitude fatigue. Monday’s race gets rolling at 2 p.m. All television coverage of the race will be on NBCSN, including a nightly recap show. Check local listings for details. The race can also be streamed live online, details are available at www.usaprocyclingchallenge.com.