Xavier,
I assume you are asking about racing Breck Epic. Pacing for this race depends on how acclimatized to the altitude you are.
1 – What altitude do you live at?
2 – How many days before the start of the race will you arrive in Breckenridge or at a location above 9,000 feet?
3 – Have you done any specific training at altitude or used an altitude tent to pre-acclimatize?
Coach Lynda