Hey there Elgin, thanks for your post. It is a little vague so really understanding exactly what they mean and exactly the issue is hard to determine.
“Holding” air implies closing the throat?! If that is the case it is cetainly undesirable.
“Upper Chest” sounds like a reference to Claude Gordons approach to the expanded chest. We can get carried away with “is it right or is it wrong”.
The air goes into the lungs! What we do with the body to get air into the lungs varies. There are two main yet conflicting approaches, the CG and Yoga expansion of the ribs up to the collar bones on an outward trajectory OR the suck inwards of the “belly” and expand the lungs upwards by raising the shoulder i.e. Roger Ingram, Bobbby Shew, Wedge Breath.
Both of these approaches, if done incorrectly, can create major problems; usually choking and overblowing.
So to answer your question, YES I have heard of it and YES it can be a concern but doesn’t necessarily have to be.
Confusion arises when we align ourselves with a particular approach at the expense of all others.
This touches on many deep issues regarding the overall psychology of learning and teaching.
Blanket statements can be easily mis-interpreted and often mis-informed.