Manual testing of the postural muscles can provide much of the information needed to plan supportive care for spinal adjustments

The best posture is one in which the body segments are balanced in the position of least strain and maximum support with full mobility. Optimal posture allows for pain-free movement with a minimum of energy expenditure. Also, it is a sign of vigor and harmonious control of the body.¹ One useful diagnostic procedure in chiropractic is the manual testing of the muscles responsible for maintaining postural alignment. This part of an examination provides valuable clinical information, which can be correlated with a patient’s history and reported symptoms.

Postural patterns are maintained by a complex arrangement of proprioceptive input and modified by habits, somatotype, and psychogenic factors such as self-esteem. Deviations from the ideal, efficient alignment eventually result in the production of chronic pain symptoms, which have been shown to be predictable.² Chiropractic adjustments can improve the segmental malalignments, but comprehensive and effective care require that muscle imbalances be addressed.

The Short and Long of Muscles
Persistent faulty postural alignment is almost always associated with an imbalance in the surrounding musculature. Sustained malalignments result in some muscles becoming shortened and others developing a constant overstretch. When certain muscles are used more frequently (at work or during sports), they get stronger and tighter while the underutilized opposing muscles become, by comparison, weaker. The eventual consequence is a malposition of the involved joint(s).Trying to determine which came first—the alignment problem or the muscle imbalance—does not really matter; both will need to be addressed.

Alignment and imbalance are usually bound together into neurological habit patterns unnoticed by patients. Doctors must identify the structures and muscles involved so that patients can begin to work on a corrective program of rehabilitative exercise.

Imbalance Patterns
Over time, many develop a similar, almost standardized configuration of muscle imbalance. While there are many individual variations due to work habits and sport activities, there is a consistent pattern primarily due to the way postural muscles are used. There also seems to be a neurological developmental component, because these patterns are common and widespread.³

Upper body patterns. The postural muscles of the neck, upper and middle back, and shoulder girdle demonstrate this type of configuration in an obvious manner. It is common to find tightness and trigger points in the neck extensor muscles, the upper trapezius, and the levator scapulae muscles. The opposing groups (longus colli and capitis and lower trapezius) are frequently lax and in need of strengthening. In the shoulder, the muscles in the front (pectoralis major and minor) are usually tight and hypertonic, while the infraspinatus, teres minor, rhomboids, and thoracic erector spinae muscles are inhibited. These muscle imbalances develop into the common postural pattern of forward shoulders and increased kyphosis, with a forward head and loss of the cervical lordosis.

Lower body patterns. Similar muscle imbalances are frequently found in the lumbar spine and pelvic region. The lumbar erector spinae muscles are often tight and hypertonic, while the abdominal muscles are lax. When the hip flexor muscles are tight, the gluteus maximus muscles become weak, thereby interfering with full hip extension during gait. This combination is suspected to be a contributing factor in hamstring muscle strains and tears.⁴

Tight hip flexors inhibit the hamstrings, which are under more stress during strenuous hip extension since the glutei are not being of much help. The result is excessive stress on the hamstrings, causing a sudden tear injury. Tight hip adductor muscles are frequently found in conjunction with weakness of the gluteus medius and minimus muscles; this can develop into a chronic groin strain.

Put to the Manual Test
Standard methods of muscle testing are well described by Kendall: “Muscle imbalance distorts alignment and sets the stage for undue stress and strain on joints, ligaments, and muscles. Manual muscle testing is the tool of choice to determine the extent of imbalance.”⁵

Be aware of recruitment, also called substitution, which occurs when patients with a weakened muscle tries to use another muscle to pass the test. If patients change the angle of the joint or tries to rush the test, a careful repositioning usually uncovers weak muscles. This is the reason that manual muscle testing requires practice and experience for accuracy. Otherwise, patients can fool the unsuspecting tester.

Carefully performed manual testing procedures can help to identify the specific muscle groups that are weaker and those that have become shortened so that general patterns do not have to be assumed. This permits chiropractors to develop an individualized plan to re-establish muscle balance by combining stretches for shortened muscles and strengthening and neurological stimulating exercises for the inhibited groups. In some cases, the muscle imbalance may be caused by a distant malfunction, such as when the psoas muscle is inhibited by excessive pronation.

Get Back to Balance
Successful rehabilitation programs will include individually determined exercises to regain postural muscle balance. A recently published survey⁶ of chiropractors throughout North America revealed that 97.8% of the respondents usually recommend exercise as part of their clinical routine.

Exercises should avoid those that increase the strength of the tight, strong muscles, or that stretch out the weakened, inhibited muscle groups. Commonly, the lower extremities do not provide the necessary support for the pelvis. In many cases, flexible orthotic support for foot pronation is needed. If pelvic unleveling has been identified during postural evaluation, effective treatment requires careful examination of the structures from the ground upward. CP

Kim D. Christensen, DC, CCSP, DACRB, CSCS, founded the SportsMedicine & Rehab Clinics of Washington. He is a team doctor to high school and university athletic programs, a postgraduate faculty member at numerous chiropractic colleges, president of the ACA Rehab Council, and a lecturer and the author of many musculoskeletal rehabilitation and nutrition texts. He can be reached via email: kimdchris tensen@hotmail.com.

References
1.    Panzer DM. Postural complex. In: Gatterman MI. Chiropractic Management of Spine Related Disorders. Baltimore: Williams & Wilkins, 1990:256.
2.    Griegel-Morris P, Larson K, Mueller-Klaus K, Oatis CA. Incidence of common postural abnormalities in the cervical, shoulder, and thoracic regions and their association with pain in two age groups of healthy subjects. Phys Ther. 1992;72:425–431.
3.    Lewit K. Chain reactions in the locomotor system: coactivation patterns based on developmental neurology. J Orthop Med. 1999;22:52–57.
4.    Geraci MC. Rehabilitation of the hip, pelvis, and thigh. In: Kibler WB, ed. Functional Rehabilitation of Sports and Musculoskeletal Injuries. Gaithersburg: Aspen Pubs; 1998:225.
5.    Kendall FP, McCreary EK, Provance PG. Muscles: Testing and Function. 4th ed. Baltimore: Williams & Wilkins; 1993:270.
6.    McDonald W, Durkin K, Iseman S, Pfefer M, Randall B, Smoke L, Wilson K. How Chiropractors Think and Practice: The Survey of North American Chiropractors. Ada, Ohio: Institute for Social Research, Ohio Northern University; 2003:56.