Every area has its test pieces, and Boulder, Colorado, has many. One of the most tested is Mt. Sanitas, part of the City of Boulder Open Space and Mountain Parks (OSMP). In the history of the program, OSMP has only allowed one race on its property, and that was an ascent of the Mount Sanitas Trail, which gains 1300 feet over 1.4 miles. The "Cardiac Arete" race was held October 25, 2003, and was won by Nathan Schultz in 15m27s.

The standard route starts from the South Mesa TH, off Eldorado Springs Drive, and ascends the Mesa, Shadow Canyon South and Shadow Canyon trails to the high point of South Boulder Peak. The route is seen on this map (same as for Bear Peak). Note that the Shadow Canyon Trail was heavily damaged in the flood of September 2013, and is now exceptionally technical. It's about 4.0 miles with about 3000' of elevation gain.