The point at which all three cardinal planes—or their axes—intersect defines the point around which body mass is equally distributed. This point is called the center of mass. When we move a body segment in a direction, the weight of that segment moves away from its equilibrium state, and an opposing displacement of equivalent weight is required to maintain balance.

CrossFit programming provides a more effective stimulus for improving cardiorespiratory endurance than running, rowing, cycling or other traditional monostructural protocols. Additionally, cardiorespiratory endurance and the rest of the general physical skills are best perceived of as aspects or qualities of functional movement.