I'm experiencing a persistent , painful tendon pain back of knee. Don't actually know if scar tissue is the cause .. thought I'd read this group's experience. I haven't found much info about this. You are right: I couldn't get the machine as long as I wanted. I think my PT was so amazed at my early progress that they were way too "easy" and stopped too soon. They also told me to go easy on the exercises, so I wasn't aggressive at home. The literature says I am more prone to scar tissue due to 40 years of knee problems and dozens of dislocations. The machine is pretty amazing and I've asked to get it back again. Like most who use it my ROM had initially and easily, comfortably, with zero PT pushing, had gotten to 122- 128. Then had to give back machine 🙁