In early 2012, 54 members of Fit Club, a gym in Columbus, Ohio, went to a lab at Ohio State University. The volunteers, all of whom followed the intense group workout regimen known as CrossFit, left blood samples, tested their maximum oxygen capacity, and had their body fat measured. They went through a round of measured workouts at Fit Club, too. Then, for 70 days, they performed a routine of Olympic lifts with a barbell, did calisthenics and strength work on gymnastics rings, and swung teapot-shaped weights over their heads. Forty-three subjects returned to the lab for analysis. The results were remarkable.
The academic article that followed, “CrossFit-Based High-Intensity Power Training Improves Maximal Aerobic Fitness and Body Composition,” shed scientific light on why CrossFit has grown from 250 affiliate gyms in 2007 to more than 10,000 today. At all levels of fitness, the Ohio volunteers lost body fat and increased oxygen capacity. “It was pretty impressive,” says Mitch Potterf, the gym’s owner. “People had improved quite a bit.”