Muscles in My Toes!

We try to teach Summer that her good qualities are usually the result of something she has worked for and can control.  For example, she's not just good (as in born good) at making things with play dough, she's good because she practices and works hard at making things with play dough.  But I'm not sure how this video fits in.  Is she telling us that she was born good at jumping off chairs because she was born with strong muscles (all over the place), or does she really mean that she's good because she's strong and she's only strong because she practices?  As I'm writing this I am realizing that I'm trying way too hard to think of a clever intro to this video--I don't even care what she's saying, it's just a fun video.