I've pretty much have accepted that from time to time I'll do things just to see if I can do it, and I'll end up hurting myself. Recently injured my shoulder and it feels like pull a few muscles in my right arm and shoulder. I was doing this with some slight differences. It involved these chairs that look like this Normally I do push up hops which look like this. So now the story. When I see people do push ups like the guy in the first video they end up arching their body. When I do my push up hops I keep my back straight so that I'm only using my arms. I do both deep hops and slightly bend arm hops for palm strike conditioning. I recently saw a video of my Sigung (my Sifu's Teacher) do the pushups and hoping onto cinder blocks. So silly me was going to see if I could push up hop onto 2 chairs without arching my body. I was successful but now I'm gotta do some healing time. Silly me. I probably should have taken a video then everyone could have seen that mix joy of "Yes! I did it!. I think I hurt myself" Lesson from this story: ...Well it doesn't matter, I probably didn't learn it. lol.