CrossFit describes its strength and conditioning program as “constantly varied, high intensity, functional movement,"[4] with the stated goal of improving fitness (and therefore general physical preparedness), which it defines as "work capacity across broad time and modal domains."[5] Workouts are typically short—20 minutes or less—and intense, demanding all-out physical exertion. They combine movements such as sprinting, rowing, jumping rope, climbing rope, flipping tires, weightlifting, carrying heavy objects, and many bodyweight exercises; equipment used includes barbells, dumbbells, gymnastics rings, pull-up bars, kettlebells, medicine balls, and boxes for box jumps.[6][7][8] These elements are mixed in numerous combinations to form prescribed "Workouts of the Day" or "WODs". Hour-long classes at affiliated gyms, or "boxes," typically include a warm-up, a skill development segment, the high-intensity WOD, and a period of individual or group stretching. Performance on each WOD is often scored and/or ranked to encourage competition and to track individual progress. Some affiliates offer additional classes, such as Olympic weightlifting, which are not centered around a WOD.[9]
CrossFit programming is used by 5,000 private affiliated gyms and by many fire departments, law enforcement agencies, and military organizations including the Royal Danish Life Guards,[10][11][12][13] as well as by some U.S. and Canadian high school physical education teachers, high school and college sports teams, and the Miami Marlins.[14][15][16] In addition, there are a number of gyms that use CrossFit-style exercises and workouts but are not officially affiliated with CrossFit, Inc. Many people who do CrossFit workouts on their own often post their results on CrossFit's