There are also concerns that its methodology may cause exertional rhabdomyolysis, a possible life-threatening condition also found in other sports, resulting from a breakdown of muscle from extreme exertion.CrossFit, meaning cross-discipline fitness. Greg Glassman developed the rudiment of the training regimen starting when he was 16, combining elements of gymnastics, weightlifting, and calisthenics. The first workout he created was called Fran that combined pull-ups and thrusters.It was conceived as a company in 1996 as Cross-Fit. Greg Glassman and Lauren Jenai incorporated CrossFit, Inc. in 2000.