CrossFit workouts incorporate elements from high-intensity interval training, Olympic weightlifting, plyometrics, powerlifting, gymnastics, girevoy sport, calisthenics, strongman, and other exercises. It is practiced by members of over 13,000 affiliated gyms  and by individuals who complete daily workouts (otherwise known as "WODs" or "workouts of the day"). CrossFit has come into some controversy for allegedly causing people to suffer from unnecessary injuries and exertional rhabdomyolysis, a condition in which muscle tissues die.

CrossFit is constantly varied functional movements performed at high intensity. All CrossFit workouts are based on functional movements, and these movements reflect the best aspects of gymnastics, weightlifting, running, rowing and more. These are the core movements of life. They move the largest loads the longest distances, so they are ideal for maximizing the amount of work done in the shortest time. Intensity is essential for results and is measurable as work divided by time—or power.