Workin' out!

So I'm at work and a patient's daughter came to visit and brought her 3 little kids.  On the way out she asked the oldest boy (about 5 or 6) to open the door.  He goes and is kind of huffing and puffing and says wow that door must be heavy, he sighs and says yeah.  She said wow where did you get all those muscles?!  He says I've been working out.  I haven't heard anything that cute in a long time!