There tons of exercises out there for the "core" and some focus on resisting movement (planks) while some focus on creating it (crunches).
Neither is better than the other inherently, both have a place in the realm of rehab, exercise, and performance.
Two exercises I've been playing with recently are the plank press off GHR (resisting movement) and the plank press into sit up off GHR (resisting movement into creating movement).
I'm always looking for exercises that can get pushed hard at a lower rep range and these fill that criteria really well! #abs#core