I confused a client yesterday by saying that her core muscles were stronger than most peoples, but then also telling her that her core was weak. Say what?
She was quite athletic with strong muscles throughout her body. The problem was that her core muscles weren’t as strong as her abdominal muscles. This imbalance was a source of her low back pain.
Core muscles stabilize the skeleton and give leverage to other muscles. Using superficial muscles like the rectus abdominus, pectoralis major, latissimus dorsi, quadriceps, and gluteus maximus without participation from the core will pull the skeleton out of alignment and create injury to ligaments and spinal discs.
“Is Your Ab Workout Hurting Your Back” by Tami Parker-Pope, published in the New York Times June 17, 2009 gives a great explanation and a video with some good exercises.
I agree that the exercises in the video are good for the core, but what is the core? I wrote about that previously in the article entitled “Core Exercise” with an easy exercise called Engage Your Core Through Your Feet to help you find those illusive core muscles: the pelvic floor, transverse abdominus, and multifidi. Finding the correct muscles is after all the first step in using them.
Here is another very simple (that doesn’t mean easy) exercise where you use the core to stabilize your low back, which is its real function, as you lift your legs. It also engages the core hip flexors, the psoas and iliacus muscles, but that's a different article.
Easy Core Exercise
1. Lie on your back with your knees bent and your arms at your sides.
2. Tilt your pubic bone up toward your chin and then your tailbone back. Go back and forth a few times and find the middle. Is your sacrum on the floor? If so, you have equal range of hip flexion and extension.
3. Adjust if necessary so that your sacrum is firmly on the floor.
4. Do not let your sacrum or hips move off the floor (this is the key) and lift your left leg so that your knee comes toward your chin, only as far as you can without moving your sacrum.
5. Press the opposite foot into the floor (use what you learned from the Engage Your Feet by Using Your Core exercise) if needed to stabilize.
6. Repeat with the right leg.