Normal (10) Grade:* With the hands clasped behind the head, the subject is able to flex the vertebral column (top figure) and keep it flexed while entering the hip flexion phase and coming to a sitting position (bottom figure). The feet may be held down during the hip flexion phase, if necessary, but close observation is required to be sure that the subject maintains the flexion of the trunk.
Because many people can do a curled-trunk sit-up with hands clasped behind the head, it is usually permissible to have a subject place the hands in this position (initially) and attempt to perform the test. If the difficulty of this test is a concern, have the subject start with the arms reaching forward, progress to placing arms folded across the chest, and then place the hands behind the head.
Good (8) Grade: With the arms folded across the chest, the subject is able to flex the vertebral column and keep it flexed while entering the hip flexion phase and coming to a sitting position. The strongest force against the abdominals is at the moment the hip flexors start to raise the trunk. Performing only the trunk curl is not sufficient for strength testing.
Fair+ (6) Grade: With the arms extended forward, the subject is able to flex the vertebral column and keep it flexed while entering the hip flexion phase and coming to a sitting position.
Fair (5) Grade: With the arms extended forward, the subject is able to flex the vertebral column but is unable to maintain the flexion when attempting to enter the hip flexion phase.
See p. 217 for tests and grades in cases of marked weakness of the anterior trunk muscles.
See numerical equivalents for word symbols used in The Key to Muscle Grading on p. 23.
When the abdominal muscles are too weak to curl the trunk, the hip flexors tilt the pelvis forward and hyper-extend the low back as they raise the trunk to a sitting position. Some people cannot perform a sit-up unless the feet are held down from the start Usually, these subjects have marked weakness of the abdominal muscles. They should practice the trunk curl only and avoid doing the sit-up in the manner illustrated here.
STRONG ABDOMINALS, PARALYZED
A subject with strong abdominal muscles and paralyzed hip flexor muscles can perform only the trunk curl. Flexing the trunk toward the thighs (i.e., hip joint flexion) requires action by muscles that cross the hip joint (i.e., the hip flexors). Because the abdominal muscles do not cross the hip joint, they cannot assist in the movement.
It does not matter whether the legs are extended or flexed or even held down, because no flexion can occur at the hip joints in the absence of hip flexors.
It may be noted that the subject does not raise the trunk as high from the table with legs flexed as with legs extended. The pelvis moves more freely in posterior tilt with the legs flexed. As the abdominal muscles shorten, both the pelvis and the thorax move, with the result that the thorax is not raised as high from the table as would occur if the pelvis were stabilized by the legs being in extension. (Leg braces were left on for photos in order to stabilize legs in knee-bent position.)
STRONG HIP FLEXORS, WEAK ABDOMINALS
Sit-up with low back arched (with legs extended or flexed) occurs when the abdominal muscles are very weak. The movement consists of flexion of the hip joints by action of the hip flexors, accompanied by hyperextension of the
■ti low back (i.e., lordosis). With strong hip flexors, the entire trunk-raising movement can be performed. (Compare with the photographs above, in which no hip joint flexion occurs in the absence of hip flexors.)
For many years, sit-ups were done most frequently with the legs extended. More recently emphasis has been placed on doing the exercise in the knee-bent position, which automatically flexes the hips in the supine position. Whether performed with legs straight or bent, the sit-up is a strong hip flexor exercise; the difference between the two leg positions is in the arc of hip joint motion through which the hip flexors act. With the legs extended, the hip flexors act through an arc from zero to approximately 80°. With the hips and knees flexed, the hip flexors act through an arc from approximately 50° (i.e., the starting position) to 125°, a total range of motion of approximately 75°.
Ironically, the knee-bent sit-up has been advocated as a means of minimizing action of the hip flexors. For many years, the idea has persisted, both among professionals and laypeople, that having the hips and knees bent in the back-lying position would put the hip flexors "on a slack" and eliminate action of the hip flexors while doing a sit-up, and that in this position the sit-up would be performed by the abdominal muscles. These ideas are not based on facts; they are false and misleading. The abdominal muscles can only curl the trunk. They cannot perform the hip flexion part (i.e., the major part) of the trunk-raising movement. (See illustrations on the facing page.) Furthermore, the iliacus is a one-joint muscle that is expected to complete the movement of hip flexion and, as such, is not put on a slack. The two-joint rectus femoris is also not put on a slack, because it is lengthened over the knee joint while shortened over the hip joint.
If the hip flexors are not short, an individual, when starting the trunk-raising movement with legs extended, will curl the trunk, and the low back will flatten before the hip flexion phase begins. The danger of hyperextension will occur only if the abdominals are too weak to maintain the curl—a reason not to continue into the sit-up.
The real problem in doing sit-ups with the legs extended compared to the apparent advantage of flexing the hips and knees stems from dealing with many subjects who have short hip flexors. In the supine position, a person with short hip flexors will lie with the low back hyperextended (i.e., arched forward). The hazard of doing sit-ups from this position is that the hip flexors will further hyperextend the low back, causing a stress on that area while doing the exercise, and will increase the tendency toward a lordotic posture in standing. The knee-bent position, however, releases the downward pull by the short hip flexors, allowing the pelvis to tilt posteriorly and the low back to flatten, thereby relieving strain on the low back.
Instead of recognizing and treating the problem of the short hip flexors, the "solution" has been to "give in" to them by flexing the hips and knees. Problems arise from this solution, however. The same hazard of coming up with the low back hyperextended can occur with the knees bent, and it does occur when the abdominal muscles are too weak to curl the trunk. (See p. 204.) In trying to come up, the subject requires more pressure than usual to hold the feet down, or more extension of the legs, or is aided by performing the movement quickly with added momentum. Sometimes it is advocated—inadvisably— that the arms be placed overhead and brought quickly forward to help in performing the sit-up. This added momentum enables the subject to do the sit-up, but the low back is hyperextended, causing strain on the abdominal muscles as well as stress on the low back.
The ability to do a curled-trunk sit-up should be considered a normal accomplishment. People should be able to get up easily from a supine position without having to roll over on the side or push themselves up with their arms. When there is weakness in either or both of the muscle groups involved in a curled-trunk sit-up (i.e., abdominal and hip flexor muscles) efforts should be made to correct the weakness and restore the ability to perform the movement correctly. Hip flexors may exhibit some weakness associated with postural problems, but rarely does this occur to the degree that it interferes with performing the sit-up (i.e., hip flexion) movement. The problem in performing the trunk curl results from weakness of the abdominal muscles. Using the sit-up exercise to correct the abdominal weakness is a mistake because, when marked weakness exists, the hip flexors initiate and perform the movement with the low back hyperextended.
The sit-up is a strong hip flexor exercise whether the knees are bent or the legs are extended. The hip joint moves to completion of hip joint flexion with hips and knees bent, making this type of sit-up more conducive to the development of shortness in the iliopsoas than a sit-up with the knees and hips extended.
Normal flexibility of the back is a desirable feature, but excessive flexibility is not. The hazards of the knee-bent sit-up also relate to the danger of hyperflexion of the trunk (i.e., the spine curving convexly backward). With the body in the anatomical position or supine with the legs extended, the center of gravity is slightly anterior to the first or second sacral segment. With the hips and knees bent, the center of gravity moves cranially (i.e., toward the head). The lower extremities exert less force in counterbalancing the trunk during a sit-up with the hips and knees bent than during a sit-up with the legs extended. Two alternatives exist for accomplishing the sit-up from this knee-bent position: Outside pressure must be exerted to hold the feet down (more than is required for those few who need it with the legs extended), or the trunk must curl excessively to move the center of gravity downward. This excessive flexion is portrayed as an exaggerated thoracic curve (i.e., marked rounding of the upper back), as abnormal flexion involving the thoracolum-bar area (i.e., roundness extending into the low back area), or both. Abnormal flexion involving the thora-columbar area is accentuated when the knee-bent sit-up is done without the feet being held down and with the heels placed close to the buttocks.
This subject, with arms in a JO or normal-grade test position and knees flexed, can flex the vertebral column but cannot raise the trunk any higher from the table than illustrated.
With the feet held down, the subject immediately begins the hip flexion phase and can continue to a full sitting position, as seen in the series of photographs of this same individual on p. 204.
The subject is making an effort to sit up with the arms in an easy test position and the feet not held down. It is obvious that the subject goes immediately into the hip flexion phase. Legs tend to extend in an effort to move the center of gravity of the lower extremities more distally and offset the force exerted by the trunk. These same problems exist with respect to stabilization of the feet whether the knees are extended or flexed.
EFFECT OF HOLDING FEET DOWN DURING TRUNK RAISING FORWARD
The center of gravity of the body generally is given as approximately the level of the first sacral segment, and this point is above the hip joint If V2 the body weight is above the center of gravity, then more than V2 the body weight is above the hip joint. (Basmajian states that the lower extremities constitute approximately V3 of the body weight .) For most people, this means that the force exerted by the trunk in the supine position is greater than the force exerted by both lower extremities. Usually, double-leg raising with the knees straight can be initiated without overbalancing the weight of the trunk in the supine position. Seldom, however, can the straight or hyperextended trunk (see facing page) be raised from the supine position toward a sitting position without some outside force being applied (e.g., pressure downward on the feet) in addition to that exerted by the extended extremities.
On the other hand, if the trunk curls sufficiently as the trunk raising is started, the center of gravity of the body moves downward, toward or below the hip joints. As this occurs, the curled trunk can be raised in flexion toward the thighs without the feet needing to be held down. Most adolescents (especially those with long legs in relation to the trunk) and most women can perform a sit-up with legs extended and without the feet being held down. In contrast, many men need to have some added force (usually very little) applied at the point where the trunk curl is completed and the hip flexion phase begins.
For the curled-trunk sit-up to be used as a test of abdominal muscle strength, it must be made certain that the ability to curl the trunk is actually being measured. The trunk curl must precede the hip flexion phase in the trunk-raising movement. When the feet are not held down, the pelvis tilts posteriorly as die head and shoulders are raised in initiating the trunk curl. With the feet held down, the hip flexors are given fixation, and the trunk raising can immediately become an arched-bad sit-up with flexion at the hip joints. Hence, to help ensure that the test determines the abilityto curl the mink before the hip flexion phase begins, the feet must notbe held down during the trunk flexion phase.
The question is frequently asked whether holding the feet down causes any problem if abdominal strength is normal. It might not if the subject is performing only a few sit-ups, but it might if many repetitions ate being performed. One or two curled-trunk sit-ups, properly done, determines normal strength; it does not determine endurance. An individual may grade normal and perform several sit-ups properly. With repeated sit-ups. however, die abdominal muscles may fatigue, and this same individual may "slip into" doing an arched-back sit-up. This situation arises frequently, because abdominal muscles do not have the endurance exhibited by the hip flexors.
The transition to an arched-back sit-up could—and would—go undetected if the feet were held down fiom the beginning of the sit-up. If the feet were not held down during the initial spine flexion phase, however, tie inability to curl the trunk would become obvious as fatigue sets in. An individual might be able to do as many as 100 sit-ups with the feet held down, yet no more than 5 sit-ups without the feet held down. This would indicate that the trunk-raising became an arched-back sit-up after the first five.
An individual with marked abdominal muscle weakness who, with arms in a relatively easy (grade of 6 or fair+) test position, is unable to flex the lumbar spine and complete the sit-up when the feet are not held down.
The same individual shown in Figure A who, with arms in a 10 or normal-grade test position, is able to perform the sit-up by hip flexor action because the feet are held down. As a test, this only measures hip flexor strength.
To strengthen the abdominal muscles that show weakness on the trunk-curl test, it is desirable, in most instances, to have the subject perform only the trunk-curl part of the movement. This provides the advantage of abdominal muscle exercise without strong hip flexor exercise. In addition, according to Nachemson and Elfstron, less intradiscal pressure occurs when doing only the trunk curl as compared to completing the sit-up (6).
When the subject can perform the trunk curl to completion of spine flexion, the resistance may be increased by folding the forearms across the chest and completing the curl. Later, more resistance can be added by placing the hands behind the head and completing the curl. At each stage, work to achieve some endurance (i.e., completion of curl, holding it for several seconds and repeating approximately 10 times).
Abdominal Exercise, Trunk Curl: In the back-lying position, place a small roll under the knees. Tilt the pelvis to flatten the lower back on the table by pulling upward and inward with the muscles of the lower abdomen. With arms extended forward, raise the head and shoulders from the table. Raise the upper trunk as high as the back will bend, but do not try to come to a sitting position.
Abdominal Exercise, Assisted Trunk Curl: If the abdominal muscles are very weak and the subject cannot lift the shoulders from the table, modify the above exercise by placing a wedge-shaped pillow (or the equivalent) under the head and shoulders. This position enables the subject to exercise within a short range of motion. As the ability to hold the completed curl improves, use a smaller pillow and have the subject flex to completion of the curl.
Abdominal Exercise, Short Hip Flexors: When the hip flexor muscles are short and restrict the posterior pelvic tilt, modify the above trunk curl exercise by temporarily placing a pillow under the knees to passively flex the hips, as illustrated.
Double-leg raising from a supine position is flexion of the hips with the knees extended. With the knee extensors holding the knees straight, the hip flexors raise the legs upward. No abdominal muscles cross the hip joints, so these muscles cannot assist directly in the leg-raising movement. The role of the hip flexors is made very clear by observing the loss of function when they are paralyzed, as seen in the drawing below.
To perform the double-leg-raising movement from a supine position, the pelvis must be stabilized in some manner. The abdominal muscles cannot enter directly into the leg-raising movement, but the strength or weakness of these muscles directly affects the trunk position and how the pelvis is stabilized. Leg raising through hip flexor action exerts a strong pull downward on the pelvis in the direction of tilting it anteriorly. The abdominal muscles pull upward on the pelvis, in the direction of tilting it posteriorly.
A subject with strong abdominal muscles and very weak or paralyzed hip flexors cannot lift the legs upward from a supine position. In attempting to raise the legs, the only active movement that occurs is that the pelvis is drawn forcefully into posterior tilt. Passively, the thighs may be raised slightly from the table secondary to tilting of the pelvis, as illustrated above, or they may remain flat on the table if the anterior hip joint structures are relaxed.
If the subject has strong abdominal muscles, the back can be held flat on the table by the abdominals holding the pelvis in posterior tilt during the leg-raising movement.
If the abdominal muscles are weak, the pelvis tilts anteriorly as the legs are lifted. As this tilt occurs, the back hyperextends, often causing pain, and the weak abdominal muscles are put on a stretch and are vulnerable to strain.
When discussing the actions of the abdominal muscles, it should be recognized that various segments of the abdominal musculature are closely allied and interdependent. The external oblique, however, is essentially fan-shaped, and different segments may have different actioiis. The pelvis can be tilted posteriorly by an upward pull on the pubis, by an oblique pull in an upward and posterior direction on the anterior iliac crest; or by a downward pull posteriorly on the ischium. The muscles (or parts of muscles) that are aligned in these di rections of pull are the rectus abdominis, the lateral fibers of the external oblique, and the hip extensors. These muscles may act to tilt the pelvis posteriorly whether the subject is standing erect or lying supine. In the supine position, however, during double-leg lowering, the hip extensors are not in a position to assist in maintaining flexion of the lumbar spine and posterior pelvic tilt. Consequently, the rectus abdominis and external oblique muscles assume the major role in maintaining the position of the low back and pelvis during the leg-lowering movement.
The lateral fibers of the external oblique act to tilt the pelvis posteriorly, and they may do so with little or no assistance from the rectus abdominis. The subject's arms are placed overhead to expose the drawings on the abdomen. (For arm position during testing of the lower abdominals, see pp. 213 and 214.)
External oblique. —ïg lat fibers ffi
External oblique. —ïg lat fibers ffi
Action by the rectus abdominis and external oblique is required to maintain the pelvis in posterior tilt and the low back flat on the table as the legs are raised or lowered.
ANTERIOR TRUNK FLEXORS: LOWER ABDOMINAL MUSCLE TEST
Anterior trunk flexion by the lower abdominal muscles focuses on the ability of these muscles to flex the lumbar spine by flattening the low back on the table and then holding it flat against the gradually increasing resistance provided by the leg-lowering movement.
Patient: Supine on a firm surface. A folded blanket may be used, but not a soft pad. Forearms are folded across the chest to ensure that the elbows are not resting on the table for support.
INote: Avoid extending the arms overhead or clasping the hands behind the head.
Fixation: No fixation should be applied to the trunk, because this test determines the ability of the abdominal muscles to fix the pelvis in approximation to the thorax against resistance provided by the leg-lowering movement Giving stabilization to the trunk would be giving assistance. Allowing the patient to hold onto the table, or to rest the hands or elbows on the table, would also be providing assistance.
Test Movement: The examiner assists the patient in raising the legs to a vertical position, or the examiner has the patient raise the legs one at a time to that position, keeping the knees straight. (Hamstring tightness will interfere with obtaining the full starting position.)
Have the subject tilt the pelvis posteriorly to flatten the low back on the table by contracting the abdominal muscles and then hold the low back flat while slowly lowering the legs. Focus attention on the position of the low back and pelvis as the legs are lowered. The subject should not raise the head and shoulders during the test.
Resistance: The force exerted by the hip flexors and the leg-lowering movement tends to tilt the pelvis anteriorly and acts as a strong resistance against the abdominal muscles, which are attempting to hold the pelvis in posterior tilt As the legs are lowered by the eccentric (i.e., lengthening) contraction of the hip flexors, leverage increases and provides increasing resistance against the abdominal muscles for the purpose of grading the strength of these muscles.
Grading: Strength is graded based on the ability to keep the low back flat on the table while slowly lowering both legs from the vertical position (i.e., 90° angle).
The angle between the extended legs and the table is noted at the moment that the pelvis tilts anteriorly and the low back arches from the table. To help detect the moment when this occurs, the examiner may place one hand at—but not under—the low back and the other hand with the thumb just below the anterosuperior spine of the ilium. When testing patients with weakness or pain, however, place the thumb of one hand just below the anterosuperior spine, and leave the other hand free to support the legs the moment the back starts to arch.
The leg-lowering test for abdominal strength is not applicable to very young children. The weight of their legs is small in relation to the trunk, and the back does not arch as the legs are raised or lowered. Furthermore, at the age of 6 or 7 years, when the test would have some significance, it is not easy for a child to differentiate the actions of various muscles and try to hold the back flat while lowering the legs. From approximately 8 or 10 years of age, it is possible to use the test for many children. As adolescence approaches and the legs grow long in relation to the trunk, the picture reverses from that of early childhood, and the leverage exerted by the legs as they are lowered is greater in relation to the trunk. At this age, grades of fair+ or good-on the leg-lowering tests should be considered as "normal for age" for many children, especially those who have grown tall very quickly. After 14 to 16 years of age, males should grade normal, and females should grade good. Because of the distribution of body weight, men have an advantage in the leg-lowering test and women in the trunk-raising test. Staniszewski, et al., found the leg lowering test to be reliable and valid for adults (7).
See the numerical equivalents for word symbols used in The Key to Muscle Grading on page 23.
Fair+ (6) Grade: With arms folded across the chest, the subject is able to keep the low back flat on the table while lowering the legs to an angle of 60° from the table.
Good (8) Grade: With arms folded across the chest, the subject is able to keep the low back flat while lowering the legs to an angle of 30° from the table. (In this photograph, the legs are at a 20° angle.)
Normal (10) Grade: With arms folded across the chest, the subject is able to keep the low back flat on the table while lowering the legs to table level. (In this photograph, the legs are elevated a few degrees.)
A subject with marked weakness of abdominal muscles and strong hip flexors can hold the extended extremities in flexion on the pelvis and lower them slowly, but the low back arches increasingly as the legs approach the horizontal. The force exerted by the weight of the extremities, and by the hip flexors holding the extremities in flexion on the pelvis, tilts the pelvis anteriorly, overcoming the force of the weak abdominal muscles that are attempting to pull in the direction of posterior tilt.
The lower abdomen is pulled upward and inward, and the pelvis is tilted posteriorly to flatten the low back on the table by action of the external oblique (especially the posterior lateral fibers). The subject should be taught to palpate the lateral fibers of the oblique to ensure their action, and to avoid using the gluteus maximus to tilt the pelvis when doing this exercise.
Pelvic tilt may be done with the rectus abdominis, but it should not be done in this manner when attempting to strengthen the external oblique.
2 , .
EXTERNAL OBLIQUE STRENGTH EXERCISE
Strong external oblique muscles play an important role in maintaining good postural alignment and in preventing low back pain. Exercise to strengthen these muscles must be specific as illustrated above. Weakness of the external oblique is common in persons performing excessive sit-up exercises because the posterolateral fibers of the external oblique elongate during the trunk curl. (See p. 201.)
The sitting position offers resistance for the external obliques in holding the lower abdomen "up and in" and keeping the low back flat. In addition, the rotation of the thorax on the pelvis, as illustrated above, requires strong unilateral action alternately by the right and left external oblique muscles.
Starting Position: Sit erect in a chair or on a stool, facing forward with feet on the floor and legs together. This position stabilizes the pelvis. Place hands on top of the head to help keep the chest up and the upper back in good alignment.
Exercise: To strengthen the left external oblique, slowly rotate the upper trunk toward the right (clockwise), holding the position for several seconds. Relax and return to midline. To exercise the right external oblique, slowly rotate the upper trunk toward the left (counterclockwise), holding the position for several seconds. Relax and return to midline.
Note: Exercises may be performed in standing but it is more difficult to fix the upper trunk because the pelvis rotates toward the same side as the external oblique.
When the one-joint hip flexors are short, they hold the pelvis in anterior tilt and the low back in hyperextension when standing or when supine with the legs extended. From this position, it is difficult—if not impossible—to do posterior pelvic tilt exercises to strengthen the abdominal muscles. Because the head-and shoulder-raising movement involves a simultaneous posterior pelvic tilt, interference occurs with this exercise as well.
As an effort is made to tilt the pelvis, the short hip flexors become taut and prevent the movement. To release this restraint and make tilting die pelvis easier, the knee-bent position has been widely advocated.
This position obviously gives in to the short, tight hip flexors. It also makes it relatively easy to perform the tilt, often merely by pressing the feet against the table to "rock the pelvis back." With shortness of the hip flexors, die hips and knees should be bent, only as much as needed, to allow the pelvis to tilt back. This position should be maintained passively by using a large-enough roll or pillow under the knees. From this position, the pelvic tilt and trunk-curl exercises may be done to strengthen the abdominal muscles.
Although bending the hips and knees is initially needed and justified, the position should not be continued indefinitely. Therefore, the extent and duration of modifying the exercise become important. Goals should be based on the desired end result, and exercises should be directed toward attaining it. A desired end result in standing is the ability to maintain good alignment of the pelvis with the legs straight (i.e., with the hip joints and knee joints in good alignment). Working toward this goal in exercise is accomplished by minimizing, and then gradually decreasing, the amount of hip flexion that is permitted by the knee-bent position.
Tilting the pelvis posteriorly with the legs extended as much as possible moves the pelvis in the direction of elongating the hip flexors while strengthening the abdominals. This movement is not sufficient to stretch the hip flexors, but it helps to establish the necessary pattern of muscle action when attempting to correct a faulty lor-
dotic posture in standing. Concurrent with proper abdominal exercise, the hip flexors should be stretched so that, in time, the individual will be capable of doing the posterior tilt with the legs extended. (See p. 381.)
Objective grading of the anterolateral abdominal muscles is not difficult when strength is fair (i.e., grade of 5) or above. Below a strength of fair, it is more difficult to grade accurately. The tests and grades described here furnish guidelines for grading weak muscles.
With marked imbalance in the abdominal muscles, one must observe deviations of the umbilicus (see previous page) and rely on palpation for grading.
Before doing the tests listed below, it is necessary to test the strength of the anterior neck muscles.
ANTERIOR ABDOMINAL MUSCLES (MAINLY RECTUS ABDOMINIS)
Fair— (4) Grade: In the supine position with knees slightly flexed (i.e., rolled towel under the knees), the patient is able to tilt the pelvis posteriorly and keep the pelvis and thorax approximated as the head is raised from the table.
Poor (2) Grade: In the same position as above, the patient is able to tilt the pelvis posteriorly. As the head is raised, however, the abdominal muscles cannot hold against that resistance anteriorly, and the thorax moves away from the pelvis.
Trace Grade: In the supine position, when the patient attempts to depress the chest or tilt the pelvis posteriorly, a contraction can be felt in the anterior abdominal muscles, but no approximation of the pelvis and thorax is observed.
Fair— (4) Grade: In the supine position with the examiner providing moderate resistance against a diagonally downward pull of the arm, the cross-sectional pull of the oblique abdominal muscles will be very firm on palpation and will pull the costal margin toward the opposite iliac crest. If the arm is weak, pushing the shoulder forward in a diagonal direction toward the opposite hip and holding it against pressure may be substituted for the arm movement.
In the supine position with one leg held straight in approximately 60° hip flexion, the examiner applies moderate pressure against the thigh in a downward and outward direction. The oblique muscles should be strong enough to pull the iliac crest toward the opposite costal margin. (This test can be used only if hip flexor strength is good.)
Trace Grade: A contraction can be felt in the oblique muscle when the patient makes an effort to pull the costal margin toward the opposite iliac crest (i.e., a slight lateral shift of the thorax over the pelvis, but with no approximation of these parts).
Fair- (4) Grade: In a side-lying position, firm fixation and approximation of the rib cage and iliac crest laterally will be noted during active leg abduction and arm adduction against resistance.
Poor (2) Grade: In the supine position, the patient is able to approximate the iliac crest and rib cage laterally as an effort is made to elevate the pelvis laterally or adduct the arm against resistance.
Trace Grade: In the supine position, a contraction can be felt in the lateral abdominal muscles as an effort is made to elevate the pelvis laterally or adduct the arm against resistance, but no approximation of the thorax and the lateral iliac crest is noted.
RECORDING GRADES OF ABDOMINAL MUSCLE STRENGTH
Abdominal muscle grades are recorded in two different ways. The method chosen depends on the amount of strength.
When strength is fair (i.e., grade of 5) or better in the trunk-raising and leg-lowering tests, it is usually sufficient to grade and record on the basis of these tests. (See Figure A.) Intrinsic imbalance between parts of the rec-tus or the obliques seldom necessitates grading parts separately if these tests show a grade of fair or better.
When marked weakness or imbalance exists, it is necessary to indicate the test findings in relation to specific muscles. (See Figure B.) (See p. 199.)
Poor (2) Grade: The patient is able to approximate the iliac crest toward the opposite costal margin.
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