The first thing to say is that CrossFit is for EVERYONE!
CrossFit is a strength and Conditioning (fitness) program that was originally developed by Coach Greg Glassman (a former gymnast) after years of coaching elite athletes. He found that the best way to achieve optimal fitness was not through specialisation but rather through “constantly varied functional movements (like pushing, pulling, squatting, lifting, running) performed at relatively high intensity”.
A functional move is defined as a movement which has the ability to move a large load, a long distance and quickly.
Relative intensity is based on individual abilities; for example a 24 year old professional rugby player will have a different level of fitness to a 50 year old sedentary accountant. The intensity is scalable to all so that they can receive an equivalent stimulus whilst completing identical movement patterns. The needs of Olympic athletes and our grandparents differ by degree not kind. Our fire service, chess champions, ice climbers and housewives have found their best fitness from the same regimen.
CrossFit is typically conducted as group training sessions, which last one hour.