By eliminating postural abnormalities, our children can grow up pain free, with minimal stress on their young musculoskeletal systems

Patients report for chiropractic treatment for various reasons. The most common reason is for treatment to reduce or eliminate pain, and also to improve function. This concept of decreasing pain and increasing function is especially significant in our young patient population.

After performing a careful and complete history and physical examination, a chiropractor is often able to identify the nature and extent of a patient’s pain and disability. Once a correct diagnosis is established, the correct treatment becomes intuitive.

Occasionally, the nature of a patient’s pain and dysfunction has no apparent diagnostic cause. The patient cannot recall a precipitating event; nothing specifically provokes or relieves the pain; and in general, the history is very nonspecific. Physical examination findings may contribute to the doctor’s dilemma, with negative test results and inconsistent findings. This situation can be frustrating for the patient, doctor, and parents of the young patient.

Perhaps the most unfortunate part of this scenario is when the patient is given a provincial diagnosis of growing pains or bursitis and is sent on his way. This segment of the patient population is at risk of developing chronic and recurrent episodes of pain.

Care at Great Cost
The cost of caring for this population has a devastating price, financially and also in terms of personal suffering. The financial cost of caring for people with low back pain in the United States is estimated at $60 billion per year, and $27 billion is spent on patients with permanent disability.¹ It appears that pieces are missing from the puzzle of diagnosis and care of chronic pain sufferers—an area of investigation that might aid in the improved care of our younger patient population and possibly decrease the onset of chronic pain and disability we see when these young patients develop their fully mature musculoskeletal systems.

One area deserving increased attention is the examination of posture and the identification of muscle imbalances responsible for those postures. A brief description of muscle physiology is a necessary basis for the appreciation of the development of pain syndromes and movement impairment.

Postural Imbalances
Posture has been defined as a “composite of the positions of all the joints of the body at any given movement.”2 It is important to understand some consequences of poor posture and how to maintain a healthy posture. Healthy posture is more than sitting up straight and not slouching. A posture can be adequately assessed by a plumb line analysis. The plumb bob is lined up anterior to the lateral malleolus. The plumb line should then pass slightly anterior to the center of the knee joint, approximately through the greater trochanter, midway through the trunk, through the shoulder joint (with arms hanging normally in relation to the trunk), and through the external auditory meatus. This is the presentation of an ideal posture.

In an ideal posture, the agonist and antagonist muscles are in balance; there is decreased stress on the muscular system, so we conserve energy; and the skeletal system has normal stress across the joint surfaces. Poor posture can result in muscle sprains and strains, pain and spinal problems, decreased lung capacity, and digestive problems. It can also lead to nerve-entrapment syndromes, such as thoracic outlet and carpal tunnel. Medial stress syndrome, plantar fasciitis, and heel spurs are but a few of the conditions related to poor posture.

If an assessment is made, information can be gathered regarding which muscles are in a lengthened position and which are in a shortened position. Generally, those muscles that are slightly shortened tend to be stronger, and those that are slightly elongated tend to be weaker than the muscles that work in opposition to them. The effect of muscle imbalances on the joints can manifest as loss of flexibility and decreased range of motion. If not corrected with chiropractic manipulation, joint mobilization, and muscle lengthening and strengthening techniques, this muscular tug of war can result in a permanent loss of motion.

When applied to the human skeleton, these muscular conditions create faulty alignment that may give rise to stretch weakness or adaptive shortening of the muscles. These imbalances in muscles give rise to faulty postures with names such as sway back, flat back, hyperlordosis, military, and several others. When we discuss posture, we are evaluating the condition of the entire musculoskeletal system.

We must further analyze the condition of individual joints. In the military-type posture, the knees have a tendency toward hyperextension, the pelvis is tilted interiorly, and there is an increased lumbar lordosis. The effect this posture has on the muscular system is predictable; the rectus abdominis muscle is elongated, the hip flexor muscles and low back muscles have a tendency toward shortening, and the hamstrings are lengthened past their ideal resting length. In this posture, subsequent muscle imbalances create stiffness that will decrease range of motion and mobility, and must be addressed to decrease the cumulative effects of continual abnormal stress created by these uneven forces exerted in the musculoskeletal system. These changes are very important in the immature skeleton.

Muscle Types
A brief explanation of functional division of muscle-fiber types is necessary to appreciate the tendencies of muscles in obtaining various postures. Type 1 muscle fibers are those that are slow oxidative and describe their slow shortening speed and dependence on oxidative metabolism. Type 1 fibers have a low glycolic capacity, contract slowly, relax slowly, are fatigue resistant, and generate low-force capacity. These muscle fibers make up our postural muscles and are prone to shortening and tightness. These are the muscles chiropractors stretch frequently, in an attempt to relieve pain and restore function. A list of muscles made up of Type 1 muscle fibers would include the gastroc-soleus group, hamstrings, rectus femoris, iliopsoas, tensor fascia lata, piriformis, paravertebral back extensors, quadratus lumborum, pectoralis major, upper trapezius, levator scapula, and sternocleidomastoid.

Another pertinent group of muscle fibers is Type 2, fast twitch fibers. An understanding of the physiologic characteristics of fast twitch fibers is necessary. They have a high glycolytic capacity and low-to-medium oxidative capacity. Their speed of contraction is fast; they relax quickly, have a low resistance to fatigue, and have a high force capacity. This group of fibers is called fast oxidative muscle fibers. Type 2 muscle fibers make up our phasic muscles and are prone to weakness. A list of phasic muscles would include the peronei, tibialis anterior, vastus medialis and lateralis gluteus maximus, medius and minimus, rectus abdominal, serratus anterior, rhomboids, lower trapezius, and the short cervical flexors.

These muscle groups work cooperatively on various joints of the skeletal system in the relationship of agonist and antagonist. The effect these muscle imbalances have on the body and their unevenly exerted pulling is a factor partially responsible in the condition of degenerative joint disease (DJD). Sometimes known as joint aging, DJD has been recognized to begin in the teenage years. If left untreated, these abnormal stresses can lead to ligament dysfunction, facet joint disease, chronic groin pain, sports hernia (disruption of the inguinal canal without an apparent hernia), osteitis pubis, adductor tendinosis, bone-spur development, nerve irritation, and degenerative joint disease. Hypertonic or chronically shortened muscles have a tendency to pull joints closely together and squeeze the internal joint structures together with powerful forces that alter the biomechanics and physiologic functions of the surrounding joint.

The Origins of Musculoskeletal Pain
Muscle imbalances can lead to alterations in movement patterns. Tight muscles are more readily activated during movement patterns. Normally, the muscles around the shoulder girdle work in a muscular force couple, allowing for smooth, pain-free movement of the humerus on the glenoid. If the upper trapezius is tight, the shoulder will elevate during abduction. A weak serratus and lower trapezius will accentuate this elevation.

Janda3 identified common muscle-imbalance syndromes associated with chronic musculoskeletal pain: upper crossed syndrome and lower crossed syndrome. Upper crossed syndrome is characterized by tightness of the upper trapezius, the levator scapula, cervical extensors, sternocleidomastoid, and pectoralis muscles. There is associated weakness of the deep neck flexors, serratus anterior, and middle and lower fibers of the trapezius. The lower crossed syndrome is characterized by tightness of the thoraco-lumbar erector spinae, rectus femoris, and iliopsoas. There is associated weakness of the abdominal rectus and transverses, and gluteus maximus and minimus.

Watching Over Young Patients
As chiropractors, we have an obligation to our young patients to see to it that their developmental years are healthy ones. By eliminating postural abnormalities, our children can grow up pain free, with minimal stress on their young musculoskeletal systems.

After corrections are made, advise children and parents about posture education. Remind them to avoid prolonged postures, check them for scoliosis as necessary, discuss appropriate use of backpacks, encourage regular activity, and provide stabilizing orthotics and posture-specific exercises. CP

Manuel Duarte, DC, MS, DACBSP, DABCO, CSCS, is a graduate of National College of Chiropractic. He has extensive teaching experience and lectures on a variety of topics, including manual treatment procedures, rehabilitation, orthopedics, and sports medicine.

References
1. Evans AM. Relationship between “growing pains” and foot posture in children. J Am Podiatr Med Assoc. 2003;93(2):111–117.
2. Michaud TC. Foot Orthoses and Other Forms of Conservative Foot Care. Baltimore, MD: Williams & Wilkins, 1993.
3. Janda V. Muscles and motor control in low back pain: assessment and management. In: Twomey LT, ed. Physical Therapy of the Low Back. New York: Churchill Livingstone,1987:253–278.