This functional fitness challenge in Frederick, CO offers two ways to push your limits across 8 different workout zones. Choose Cerox if you want to mix running with strength and cardio stations, or go with Cerox Iron for the same zones minus the running portions. Whether you compete solo or pair up with a teammate, you'll tackle exercises like rowing, deadlifts, ski ergs, sandbag work, lunges, farmer carries, bike sprints, and burpees—customize how you and your partner divide the work to match your strategy.