| Description |
Within the past decade, the public has become very health conscious. Both public and individual exercise programs have increased significantly in our country. If there is even a remote possibility that muscle imbalance created by some of the common exercises performed today could lead to low back problems, then there would be justification for emphasizing the elimination of their interrelationship use. An improved understanding of the interrelationship between the abdominal and the iliopsoas muscles during selected movements would add greatly to our knowledge concerning both immediate and future implications to the spine and its related structures created by any or all of the most common exercises performed today by both healthy individuals and by those already suffering from back problems who are being treated therapeutically with potentially deleterious exercise programs. This investigation determined the function of the rectus abdominis and the iliacus muscles during performanceof popular exercises purported to be beneficial in cases of back pain, malposture, or where abdominal strength increase is desired. The research method of electromyographically recording the action potential amplitude produced during exercise was used. Twelve subjects ranging in age from 22 to 37 were subjected to this test during the performance of the following exercises: 1. Longlying sit-ups with the feet supported. 2. Longlying sit-ups without support to the feet. 3. Hooklying sit-ups with the feet supported. 4. Hooklying sit-ups without support to the feet. 5. Longlying curl-ups with the feet supported. 6. Longlying curl-ups without support to the feet. 7. Hooklying curl-ups with the feet supported. 8. Hooklying curl-ups without support to the feet. 9. Simultaneous straight leg raises. 10. Quiet standing. The results obtained from the investigation substantiated the premise that curl-ups are superior to sit-ups in involving the rectus abdominis muscle to the greatest extent. Hooklying curl-ups elicited greater intensities of action potential from the rectus abdoinis than did longlying curl-ups substantiating the preference of the hooklying position over the longlying position as an exercise for abdominal musculature. In every variation used in this investigation there was significantly more iliopsoas muscle action potential evoked when the feet were stabilized than when the feet were not stabilized. When the feet were held down this essentially stabilized the insertion of the iliopsoas muscle thus offering it a maximal opportunity to approximate its origin to its insertion. It is not beneficial to exercise this muscle to the point of developing disproportionate strength over the abdominal muscles. The preferred method of exercising the abdominal muscles while evoking the least activity from the iliopsoas muscle is curl-ups from the hooklying position with no support to the feet. The results elicited from the simultaneous straight leg raises left little doubt that this exercise should not be considered beneficial for strengthening abdominal muscles. |
