WHAT IS CROSSFIT

CrossFit is a strength and conditioning program consisting mainly of a mix of aerobic exercise, gymnastics (body weight exercises), and Olympic weight lifting. CrossFit Inc. describes its strength and conditioning program as "constantly varied functional movements executed at high intensity across broad modal and time domains," with the stated goal of improving fitness, which it defines as "work capacity across broad time and modal domains."

Hour-long classes at affiliated gyms, or "boxes", typically include a warm-up, a skill development segment, the high-intensity "workout of the day" (or WOD), and a period of individual or group stretching. Some gyms also often have a strength focused movement prior to the WOD. 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. CrossFit gyms use equipment from multiple disciplines, including barbells, dumbbells, gymnastics rings, pull-up bars, jump ropes, kettlebells, medicine balls, plyo boxes, resistance bands, rowers, and various mats. CrossFit is focused on "constantly varied, high-intensity, functional movement," drawing on categories and exercises such as these: calisthenics, Olympic-style weightlifting, powerlifting,Strongman-type events, plyometrics, body weight exercises, indoor rowing, aerobic exercise, running, and swimming.
Source: Wikipedia