Originally Posted by
Rob Israel
Yea, sorry, I kind of combined two things: my feeling about certain exercises and my attitude towards working the spinal erectors directly. Also, I'm not saying that flexion is bad per se, I'm saying moving in and out of flexion (to extension) repeatedly is bad.
I'm against those exercises (crunches and extensions) because I believe they are potentially problematic over the long term. Granted, you may be getting relief from them, but if the flexion part of the exercise is helping your back, I would just hang there, not moving, in flexion! (boring but a nice way to get some traction and relax the back)
It is my current belief that any exercise that repeatedly moves the spine from extension to flexion is going to eventually damage the discs. If you can do a crunch and not flex at all, more power to you but it will be a much shorter ROM and I have never seen anyone actually do it. By neutral, I mean dead neutral.
A friend likens these movements to a bending a credit card over and over-- eventually it will break. I don't think that's the best analogy, but the fact is when you extend you are squeezing the back of the disc and when you flex you are squeezing the front. Yes, this is what the spine was designed to do but not in the manner we do them in these exercises: for high reps, many sets and many, many times over the course of the year. The discs are not build for that kind of assault. That's really all I'm suggesting and why I avoid these things and focus on planks and isometric stuff for my ab work. And don't get me started on russian twists-- I totally fucked myself up with those.