According to its creators, CrossFit is a “strength and conditioning program for many police academies and tactical operations teams, military special operations units, champion martial artists, and hundreds of other elite and professional athletes worldwide.”

And yet it’s now a mainstream regimen that has taken the fitness world by storm. Anyone willing to endure the extreme high intensity workouts can sign up. The results? Strength and lean physiques for some. But only at the cost of extreme pain and fatigue for even the most athletic participant.

Over the past decade, CrossFit has attracted both loyal followers and harsh critics.