This 2003 CrossFit Journal article captures an early conception of a universal, multi-event test of fitness that laid the foundation for CrossFit competition, including what would become the CrossFit Open and the CrossFit Games. The design requirements for such a test "included but were not limited to the following: quantifiable results; consistency with the CrossFit fitness concept; raising our commitment to improving absolute strength, relative strength, and gymnastic foundations; balancing intrinsic abilities of smaller and larger athletes; emphasizing exercises critical to and foundational to advanced training; mixing training demands within each test and, of course, over the total competition; a design that would identify an athlete’s weaknesses and possibly stand as a workout plan for improving overall fitness; and, finally, we wanted to design a competition that would be 'hard as hell.'"

The heart of the muscle-up is the transition from pull-up to dip — the agonizing moment when you don’t know if you’re above or below. That moment — the transition — can last from fractions to dozens of seconds. At low, deliberate speeds, the muscle-up takes a toll physically and psychologically that can only be justified by the benefit. No other movement can deliver the same upper body strength. Period.