Do you teach progressive abdominal contraction to your students? (sequencewiz.org)
I mean it, the kettlebell stimulates tremendous abdominal contraction because of the explosive conditioning movements that you use it with. (theathleticbuild.com)
Even more abdominal contraction will occur when your belly button is strongly pulled inward, as if it is trying to touch the spine. (philmaffetone.com)