Planks done properly are a terrific way to strengthen your abs while protecting your lower back. The days of isolating and shortening your ab muscles are history! Your core is for stabilization, not isolation. Just because you feel an isolated burn in your abdomen while doing crunches does not mean that you are strengthening your abs properly. Functional training uses multiple joints and multiple muscle groups. The video below will show you different variations of the plank.
Some people feel that planks are boring, but this is just one of the ways that I strengthen my core while maintaining a neutral posture. By realizing the value of a plank, I think you will find an effective exercise for core development and strength. So walk away from the ab machines and “walk the plank” to core stabilization.