Cerox Iron + Iron X 2026

CEROX + IRON is a late-winter functional fitness challenge in Frederick, Colorado, structured around eight workout zones instead of a traditional road course. Participants compete solo or in teams of two, choosing between Cerox, which includes running, and Cerox Iron, which confines the day's activities to the fitness stations. The shared workout menu features a 400-meter row, deadlifts, a 400-meter ski erg, sandbag lifts, walking lunges, a farmers carry, Echo bike calories, and burpees. In Cerox, athletes run 400 meters between each zone, accumulating repeated work under fatigue; Cerox Iron presents the same strength and endurance tests without the running segments. Teams of two may divide the zone work as they see fit, incorporating pacing and task selection into their strategy.