No doubt you've seen this tom foolery
Just about everyone knows what a crunch is, its quite prevalent in conventional athletics, and therein lies its problem, conventional athletics doesnt do much for being athletic anymore. Your basic p.e. classes are now based and kids doing quarter squats and knee pushups, and running a mile in lower and lower times, OH! and dont forget crunches.
The abdominal crunch is a very controversial exercise, the battle over it could be equivalent to the intensity between republicans and democrats, except in THAT instance, neither is correct. In my opinion and take on the matter, there are a multitude of core exercises that are just as, if not more effective at certain jobs than the crunch, and the crunch has only become so popular simply because its so prevalent in modern society.
As i stated in the last video response video i made, the core is used to stabilize the body during motion and when not in motion. the crunch would make bigger/stronger rectus abdominus muscles (dem 6 pack abs) now i didnt say core did i? i said the rectus abdominus, so when you focus all that effort and work on just one part of your core you can cause an imbalance, namely tight stomach pulls your upper body down slightly towards your pelvis causing rounded shoulders, thorasic kyphosis and eventally a potential for upper crosses syndrome or simply called chicken necking. the core like your body is meant to work as a unit, in muscle groups and synergies isolation of muscles has very little use unless you know HOW to utilize them in a training program, but i gear this more towards newbies, who should focus on total body movement and recruit the most muscle fibers they can in their workout.
So my professional opinion is to skip the crunch, there is no "god" of all core exercises that will get you all the things you want, pick and choose, try them all out, but the crunch is such a hot topic and there are plenty of other good things out there, why risk it is all im saying.