Yes Jamie. Exactly.
Some people will use dry shampoo or DIY dry shampoos to pump up the roots and the stems. Powder, even when brushed out, will leave a slight residue which pumps up the cuticle providing extra oomp.
Also, if you wash hair is lukewarm, almost cool water, that blows up the cuticle as does using an amplifying shampoo. Phyto and Rene Furterer both have really good volumizing shampoo products. Phyto's root lift is famous in celebrity circles.
Of course a cool/cold water final rinse combined with using the cool/cold setting on a blow dryer will result in the fullest hair possible. Add a little powder and you have even more lift.
Finally you can also do a fat hair hack with a carefully positioned hair ratt pinned underneath the crown to add height AFTER you back brush.