I think I stumbled on the reason for my recent knee pain. I am overweight and as such when I put on compression socks I had to bend my knee sideways a lot and hold it there for a while. This overextended the knee sideways and caused pain all day. After using the sock slider for about 3 days my pain started to go away and today it is almost gone. I think this is the greatest invention around. And the benefits to me were accidental.