Went to the bike store yesterday. Picked up free used bicycle inner tubes. One is being chopped up for ranger bands. At my age, I have had both shoulders worked on. Doing my daily hour work out did not prevent some left shoulder discomfort this week. (Back story, the woman was larger than I and pulled on my arm in west coast swing when she should have advanced. She ripped and destroyed my shoulder, requiring bone removal. ). I am rightfully afraid of medical stretch bands. Not only do they break, they spontaneously decompose just sitting there. A butyl rubber inner tube isn't going to break. I worked out with inner tubes yesterday. Over the next week, I will lurk on youtube to learn how the inner tubes can be used to exercise other parts of the body.