I had shoulder surgery not to long ago and I am still having issues with the bicep. In PT they used cupping as part of my therapy. I got these just a few days ago and have used them each day. I am feeling some progress in the muscle. It’s going to take time but the cupping will help. Please discuss use with PT or your DR before using on areas that have been injured or such. Read the instructions and use a really good oil or cream do they can slide good. I was not a fan of cupping at first but now I am glad I learned from PT.