I used this product for my knee that has been overused playing over 30 years of soccer and the last 5 years of running 5ks. In my knee, I've had pain inside when bending and using weights, pain when I walked up stairs, pain when I do squats. I had finished a workout that morning and I could feel the tug of the pain in my knee. I used this massager once. The next day I went to the gym. I got through four exercise machines using the lower legs that I always feel something while doing them (booty builder, leg press, leg extension, and stair climber) The leg press almost wanted to but never hurt, even after the third set. I am amazed. This is helping me and I will continue to use it. Heck, I'll use it on the other knee just to keep that one in pristine condition.