At 75, my chronic right knee is painful even in bed. During the day if feels like a tourniquet is on my knee, limiting blood supply. After 1 treatment, my pain was greatly reduced. It came back next day, and another treatment mostly put it away. After 4 days I feel like both legs have been exercised heavily (a good thing) and the knee pain at a minimum. This is when only using the machine for 15 minutes at powers 1-10 of 60. Its really really great. So glad I purchased it.