It's gotta be 20+ years ago. I was doing Tae Kwon Do then, and bought a machine from Century Martial Arts. The 1st day I got it, I went to 180 degrees. An hour or 2 later, my body went into some kind of shock, I got the chills and puked up (I remember it since I went to see Blood Sport at the movies). After that I went about it more gradually. For BJJ, you build up flexibility naturally through the movement. I also think yoga is good. I would stay way from the machines.