It is a common dysfunction in western cultures to lift and try to expand the ribcage when breathing in, while dragging the gut in. It results in a much smaller breathing volume, lots of weird, unnecessary physical stresses. Kind of the same kind of thing as people bending their spine weirdly backward when told to stand up straight.
I used to do this as a kid, and noticed it at one point and thought it weird. I must have subconsciously corrected it over the years since then cause it's not how I breath any more …