For years we were told that the “core muscle” was the ab and there was a great emphasis on working the muscle for a stronger back as well as a slimmer waistline. School gym teachers praised children who could do the most sit-ups and crunches in a minute. Many kids came home with painful backs. Now those routines are out-of-favor because they are harmful for the back.
The January 3, 2013 issue of Harvard HEALTHbeat, writes:
Sit-ups once ruled as the way to tighter abs and a slimmer waistline, while “planks” were merely flooring. Now planks — exercises in which you assume a position and hold it — are the gold standard for working out your core, while classic sit-ups and crunches have fallen out of favor. Why the shift?
One reason is that sit-ups are hard on your back — by pushing your curved spine against the floor and by working your hip flexors, the muscles that run from the thighs to the lumbar spine of the lower back. When hip flexors are too strong or too tight, they tug on the lower spine, which can be a source of lower back discomfort.
Second, planks recruit a better balance of muscles on the front, sides, and back of the body during exercise than sit-ups, which target just a few muscles. Remember, your core goes far beyond your abdominal muscles.
Finally, activities of daily living, as well as sports and recreational activities, call on your muscles to work together, not in isolation. Sit-ups or crunches strengthen just a few muscle groups. Through dynamic patterns of movement, a good core workout helps strengthen the entire set of core muscles — the muscles you rely on for daily activities as well as sports and recreational activities.
This information echoes what Dr. Stuart McGill has been advising for many years. Dr. McGill is a professor of biomechanics at the University of Waterloo, Canada. Dr. McGill is a highly regarded back-pain expert in the sports world. In an informative New York Times article of June 17, 2009, “Is Your Ab Workout Hurting Your Back” by Gretchen Reynolds, it appears that the isolation of the abs (transversus abdominis) for a core workout began with an Australian study in the 1990s. Reynolds writes:
The lab worked with patients in pain to isolate and strengthen that particular deep muscle, in part by sucking in their guts during exercises. The results, though mixed, showed some promise against sore backs.
Perhaps that is how the trend of working the abs started. Dr. McGill says that this thinking spread to trainers and through them to the public. According to him, the core is not just one muscle but a “corset” of muscles that circle the spine and hold it in place. By working on just one muscle the spine is destabilized and it loses its alignment. All the muscles must be balanced in order for the spine to bear large loads. The analogy used is that of a fishing rod. Think of the spine as a fishing rod that is held in place by muscular wires.
“If you pull the wires closer to the spine,” McGill says, as you do when you pull in your stomach while trying to isolate the transversus abdominis, “what happens?” The rod buckles. So, too, he said, can your spine if you overly focus on the deep abdominal muscles. “In research at our lab,” he went on to say, “the amount of load that the spine can bear without injury was greatly reduced when subjects pulled in their belly buttons” during crunches and other exercises.
Hollowing the belly and pressing the spine against the floor is a bad idea that has made its way into yoga studios and routines as well due to cross-pollination with trainers and fitness routines. Dr. McGill says sit-ups put a “devastating” load on the spinal disks. Instead, he suggests a side plank and a “bird dog” (in yoga it is the tiger pose or vyagharasana).
For more, please read The New York Times article, see the short video Core Values that accompanies the article, and visit Dr. McGill’s website www.backfitpro.com for his articles and more information. Readers may also want to visit a previous blog post Do Yoga Classes Hurt Your Back?