I am gearing up for STS, so did this work-out today, after a 45 min. run. I have been working out with Cathe consistently for years, and am in pretty good shape. But today, after the second set of resistance band shoulder exercises, I found myself really working to failure. My muscles were quivering and I was exhausted. So I know that I am pushing myself! This is really a great work-out, and it actually seemed to go pretty fast. Good thing. Now I need some rest!