I am a concertina player--or at least I was. 6 years ago I went to my orthopedic shoulder guy complaining of pain when I paddled either canoe or kayak. After he did an MRI, he told me to quit paddling and stop playing the concertina because of major arthritis as well as other problems in my right shoulder. [Un]fortunately, the problem has not progressed to the point where I can get corrective surgery. While I don't enjoy getting cut, I really miss playing.