I’m a traditionalist and do lots of crunches during the course of the week. I usually do them when I’m watching television. Crunches work well for me but planks are also a great way to strengthen your core and to contribute to your abs training. When I first started doing them, I was surprised at how challenging holding a basic plank could be even for just a couple of minutes. There are lots of wonderful variations on the basic plank that you can add to the rotation as well to add a little variety. If you haven’t given them a try, you should consider it. You might grow to like them just as I did.
(The following was taken from a great article on planks published on Bodybuilding.com. You can access the entire article here.)
MASTERING THE PLANK
It’s essential to master the basic front plank before moving on to more advanced variations, because it teaches the foundational cues that make all planking movements effective. And when done consistently and correctly, it will—not can, will—confer strength benefits that improve your big lifts and general athleticism. On the other hand, poor form planking can just end up just aggravating low back problems and not working your abs at all. It’s your choice!
Start off by getting into a plank position: propped on your forearms, elbows in line with your shoulders, and your toes planted firmly. Are you set up? Probably not if you’re reading this, which is fine, because we’re just getting started!
The most important element of a good plank is a neutral spine. The most common problem I see in planks is a sinking low back, but the second-most common problem is an arched back with the hips in the air. This is the type of “plank” usually favored by people who say a plank is “too easy.”
Here’s a cue to help you find the right depth. When performing an effective plank you should be able to place a broomstick down your back and the only contact points should be the head, upper back and hips. Well, someone else will probably have to place it there, but you get the idea.
Another element of a good plank is proper shoulder position. Be careful not to shrug the shoulders toward your ears. The final element is head position. Do your best to keep your head neutral, like it is when you stand straight and stare forward. Resist the urge to crane your neck up or let your head droop down. Try staring at your fists to keep good head position.
If you do it right, your body should form a straight line from your head to your ankles. Every one of the cues I mentioned makes it more difficult to do that—which is the point. Allow me to repeat it one more time: Planks are not supposed to be easy.
ADVANCED BODYWEIGHT PLANKS
The basic front plank is an isometric movement, meaning you’ll hold in a static position for a predetermined amount of time. Some people like to work up to holding it for minutes on end—and there’s nothing wrong with that.
However, if you can hold a good form plank for 45-60 seconds without too much quivering and grunting, you have earned the privilege of moving on to more difficult variations, if you want. Just like a standard plank, each of these doesn’t require anything more than your body and an iron will. They’ll feel grueling and unstable at first, but improving at them will train your entire midsection from the inside out.