by Dennis Zacharkow, PT
© 2014
The potential problems associated with sit-up exercises are as follows:
According to Schultz (1983), "In a maximum voluntary attempted trunk flexion the rectus abdominis muscles provide about 40 percent and the medial groups of the internal and external oblique muscles each provide about 25 percent of the strength." These "upper abdominals" should be grouped with the flexors of the body, whereas the important postural "lower abdominal" muscles are grouped with the extensors of the body (Rathbone, 1934, 1936).
The "postural depression" resulting from sit-up exercises, by approximating the front of the chest to the pelvis, is very similar to the "postural depression" in kyphotic sitting postures (Anderson, 1951; Posse, 1890). (Figure 1.)
"Often the upper abdomen is constricted by overdevelopment of the upper rectus abdominis. This is especially true in women who are conscious of a prominent abdomen and who are expending misdirected effort to overcome the condition. If continuous effort is made to flatten the abdomen and the result is a constriction or deep crease just below the level of the ribs, the lower abdominal wall is made weaker and less effective in supporting organs, and the effort expended to make the abdomen less prominent does not produce the desired results" (Drew, 1945).
Frost (1938) found that with forced flattening of the abdomen, "most of the hollowing effect is in the upper abdomen, the sub-costal region, which involves definite interference with the free functioning of the diaphragm."
Mutoh et al. (1983) reported twenty-nine cases of low back pain at a Tokyo hospital over a one year period related to sit-up exercises with the knees extended and the ankles supported. Of the twenty-nine cases, the diagnosis included twenty-two cases of lumbosacral strain (75.9 percent) and four cases of a lumbar disc lesion (13.8 percent).
Armstrong (1965) stressed that "a full range of movement of the spinal column itself is very rarely necessary to or even compatible with mechanical efficiency of the body as a whole. One of the main features of the development of a good active posture is the acquisition of the ability to brace the spine at or nearly at the neutral position so that it provides a stable centre from which the limbs can act with maximum efficiency."
"In the movements of straight flexion of the trunk the rectus muscle only is employed at the beginning and the relaxed oblique muscles are distended, forming two distinct pouches or weakened areas over the lower abdomen, and by the time they contract in self-protection the mischief may have been done.
It is in such conditions and under such circumstances that hernia is likely to be acquired, because hernia, like other swellings, enlarges in the line of least resistance. Perhaps one of the most potent causes is a standing posture in which the abdomen is protruded and the chest sunken, forcing down the abdominal contents on the relaxed lower zone, and I have been struck with the number of cases in which hernia came on unconsciously, without apparent cause, other than perhaps a long walk or a fatiguing day's standing. Even repeated and violent effort seems less fruitful of cases than the dull and steady pressure on the relaxed abdominal walls" (McKenzie, 1915).
Bowen (1919) also stressed that with a weak abdominal wall, abdominal exercises should be avoided that do not bring the oblique muscles into action. "Direct flexion of the trunk by raising the head and shoulders from lying position is risky because it begins with isolated action of the rectus" (Bowen, 1919).
All
site contents are Copyright 2002-2018
The YogaBack Company
P.O Box 9113, Rochester,
MN 55903
1-800-SITTING (1-800-748-8464)
|