Fanatic Cook posted some (potentially) myth-busting videos featuring Dr Stuart McGill that may challenge your preconceptions about core exercises.
He [Dr McGill] says that a flexible back or a strong back are not protective of back injury. In fact, they are associated with more injury. The muscles of the back are meant to stabilize, to prevent movement. This is true for abdominal muscles and others of the core or torso. However, since back and stomach muscles are in constant use, they need to be maintained to provide endurance.
Now I don’t feel so bad about not being able to touch my toes by bending over at the waist. I regained the ability to do that eight years ago by following the Core Performance program. But that regimen took about five hours a week—more than I wanted to invest long-term