I nursed in the days of lifting and sustained back injuries. In the last 10+ years (I am 85) My upper and middle back muscles have weakened and I now have to pace carefully what activities - particularly involving arm movement - I do in a day If I overdo I am in pain often severely Initially a heat pack is effective then I need Rub on relief but if I persist too far its analgesics I do not ever want to be without my Rub.... It also helps greatly with my knee joints.