Just a random thought; but my husband and I were noting that our daughter with CF is a solid kid, weight wise right now. Her body has little fat but when you pick her up she feels strong and solid; with good muscle tone. Though looking at her, one may think she is skinny when you pick her up she feels heavy. My husband was commenting the constant use of the VEST must make her core strong, that she is likely very muscular inside. She also eats a very high protein and high fat diet. Any thoughts on if the VEST make you muscular from the constant pounding? A weird thought I know but interesting to me<img src="i/expressions/face-icon-small-wink.gif" border="0">