I am currently on day four of using this and it gets easier the more I use it.  The first day was very difficult to get through the entire workout.  I had trouble using my right arm for it because it just wasn’t strong enough.  The third day was much easier and today is a completely different story.  I found myself actually shaking the thing faster than I used to and that is probably because I’m getting used to it and developing more more muscle.  I still have trouble doing the final work out with out switching hands numerous times.  I do feel it in my arms for sure but not so much in my chest.  Maybe this is because the tension is the same and its not hard for me to do using the current settings.