What makes me scared is that I open up a textbook and I see it still uses the old content architecture but it's got a new section on Common Core stuff. (ncee.org)
«I no longer do core stuff on my back because I'm in the third trimester, so I'm doing more ab things while sitting in a chair or with my back against the wall.» (health.com)
Plus I lift 3x a week after running with what I think of as the big 4 --(Bench, Squat, Deadlift Shoulder Press) and body weight core stuff (pull - ups, dip, planks, push - ups etc). (scienceofrunning.com)