Fitness and Low Back Pain
By Len Kravitz, Ph.D. and Ron Andrews, M.S., P.T.

The management of low back pain is a major health and economic concern in the U.S. As one of the leading causes of physical limitation in the U.S, low back pain is a chief source of incapacitation, suffering and expense. The medical costs, not including disability claims, directly attributed to low back pain exceeded $24 billion in 1990 (Lahad, Malter, Berg, & Deyo, 1994). It is also recognized that the cause of this health problem is very difficult to establish because of the irregular nature of its occurrences in individuals and the unclear etiology of low back pain. Although the effectiveness of exercise as a prevention strategy and intervention for low back pain has recently been challenged (Lahad et al., 1994), this awareness actually suggests the need for more controlled studies that may eventually lead to the development of new and improved exercise designs that prove to be viable interventions. This article will review much of the framework about what is known about this mystery and address practical issues for the fitness instructor, personal trainer and health educator.


Low Back Pain: An Anatomical Definition
The term low back pain refers to pain in the lumbosacral area of the spine encompassing the distance from the 1st lumbar vertebra to the 1st sacral vertebra. This is the area of the spine where the lordotic curve forms. The most frequent site of low back pain is in the 4th and 5th lumbar segment.

Low Back Pain: The Known Facts
1. At some time in their life, 60% to 80% of the population will have low back pain (Cailliet, 1988) . Of those experiencing low back pain, 30% to 70% will have recurrent episodes.
2. Recovery is anywhere between 3 days and 6 weeks for 80% to 90% of acute assaults of back pain and becomes a chronic problem for 5% to 10% of the sufferers (Frymoyer, 1988) .
3. Male and female individuals are affected equally (Helliovaara, 1989).
4. There is evidence that 12% to 26% of children and adolescents experience low back pain although most cases of low back pain occur in persons between that ages of 25 and 60 yr, peaking at about 40 yr (Plowman, 1992). Low back pain and disability does not progressively increase with age and does not correspond to age-related changes of disc degeneration. It is not clear why low back pain peaks at about the fourth decade of life.
5. The majority of the population suffering from low-back pain cope with it themselves, not seeking medical treatment.
6. There is no definitive indication than any treatment for low back pain is superior than others, with evidence only showing interventions providing modest success for unknown duration (Lahad et al., 1994).
7. Persons missing work for longer than 6 months, because of low back pain, have a 50% probability of ever returning to work. Long absence from work is more dependent on socioeconomic and job-related influences, and not physical severity (Waddell, 1987). With chronic pain, Waddell expounds that the disability may become increasingly associated with emotional distress, depression, failed treatment, and the adoption of a sick role, all of which are resistant to traditional medical management.
8. Due to the lack of scientifically validated guidelines for the treatment and prevention of low back pain, the determination of exercise programs has largely been guided by empirical knowledge.
9. Most clinicians agree that the treatment of low back pain should focus on known deficiencies. Typically these sufferers lack normal levels of flexibility, muscular strength, and muscular endurance in various muscles of the trunk, including the lumbar and abdominal muscles. Often times these patients are overweight and deconditioned. Therefore, the role of exercise in the treatment and prevention of low back pain should be to correct or improve these deficiencies.
The Importance of Exercise to Care for Low Back Pain
In other parts of the body the use of exercise to improve strength, mobility, coordination, and endurance have been well recognized (Jackson & Brown, 1983). These facets of exercise are not well understood in relation to back pain. Jackson and Brown propose the following reasons to prescribe exercise for back pain: 1) to decrease pain, 2) to strengthen muscles, 3) to decrease mechanical stress to spinal structures, 4) to improve fitness level, 5) to prevent injury, 6) to stabilize hypermobile segments, 7) to improve posture, and 8) to improve mobility.


The Importance of Muscular Strength
Much emphasis has been placed on muscular strengthening exercises to add stabilization and support to the trunk area. Several arguments can be made to justify this rationale for the treatment and prevention of low back pain. For instance, the degree of stability and support of the trunk area is largely dependent on the strength of the supporting structures, the muscles. Improper vertebral alignment can result from weak back extensor muscles which may lead to undue loading on the spine. Stronger muscles can enhance the spine's ability to withstand various degrees of external loads. The fact that patients with low back pain exhibit decreased levels of trunk extension, trunk flexion, and lateral flexion strength, when compared to non-suffering persons, suggests a need to alleviate this dissimilarity. In industry, workers with high levels of muscular strength are less prone to back injury. It should be emphasized that the greatest losses in strength have been found in the trunk extensor muscles (Addison, 1980). In healthy normal persons, a natural imbalance is expected to exist with the lumbar extensors being stronger than the lumbar flexors. The trunk extensors in a healthy person are approximately 30% stronger than the trunk flexors (Foster & Fulton, 1991).

The Importance of Flexibility
Investigations suggest adequate flexibility of the oblique, hamstring, hip flexor and low back muscles is necessary for a healthy lower back (Foster & Fulton, 1991; Plowman, 1992). Patients with low back pain often exhibit consequential limitations in several movements of the pelvis and trunk. The flexibility of the lumbar spine provides for a functional mechanical advantage, while tight or shortened back muscles adversely affect spinal mechanics (Farfan, 1975). A lack of pelvic mobility, due to tightness in the hip flexors, could limit pelvic mobility and cause strain on the lumbar spine. In addition, tight hamstring and hip extensor muscles could reduce the lordotic curve, which may impair spinal loading. However, specific measures to define adequate flexibility for the reduction or prevention of low back pain have not been fully elucidated.

The Importance of Muscular Endurance
A convincing relation exists between low back pain and decreased muscular endurance. Devries (1968) found differences in EMG fatigue curves between those in whom back pain did and did not develop during prolonged postural stress. From his findings he suggested the association of muscular deficiency and low muscular endurance with low back pain. Magora (1974) also reported that occupational postural disorders, where prolonged maintenance of a particular posture occur, were a causal factor to low back pain. A clear distinction in the value of muscular strength and muscular endurance should be accentuated, since it is known that muscular endurance fitness training may be affected without a corresponding result being seen in muscular strength. It has been shown that patients with low back pain have decreased levels of muscular endurance in the lumbar extensors (Biering-Sorenson, 1984). It has also been reported that abdominal muscular endurance in patients with low back pain is less than those in the normal health population (Foster & Fulton, 1991). Therefore, these investigations support the application of endurance exercises that incorporate the back extensors as well as the abdominal muscles.


The Importance of Aerobic Exercise
Since aerobic fitness is highly associated with overall fitness and weight management, the importance of aerobic fitness to help reduce low back pain is signified, though conclusive evidence of any protective role is incomplete. This association is not as strong of a cause-effect relation that is seen with decreased levels of muscular strength, flexibility and muscular endurance with low back pain. The exact mechanism for reduced pain with aerobic exercise is not clear, since the intensity of the muscular contractions is not considered intense enough to strengthen the muscles. Aerobic fitness may help prevent any undesirable changes to the body associated with spinal inactivity, musculature weakness, and neuromuscular health. Also, the intervetebral discs are avascular (have few blood vessels) by the age of maturation, and thus rely on osmosis for disk nutrition. A well-functioning circulatory system has been shown to increase the transport of nutrients into and waste products out of the disc (Plowman, 1992)

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The Exercise Prescription for Low Back Pain
The justification of an all-around fitness program to enhance aerobic conditioning, muscular strength, flexibility and muscular endurance is well-documented in the discussion above. Adherence to well-established principles of conditioning such as specificity of exercise, progression, and overload need to be established, dependent on the fitness level, age and health of the client. Another key training concern is with range of motion. Muscular strengthening exercises of the extensor muscles often do not provide a full range of motion for this muscle group. A good example is prone torso lifts on the floor. The failure to take the lumbar extensors through the full range of motion, not incorporating the muscle fibers to their fullest, is a definite limitation. Resistance equipment manufactures have attempted to address the biomechanical concerns of range of motion and resistance throughout the exercise. However, it has been established that the eccentric contraction phase of the trunk extensors needs to be addressed for healthy back function (Floyd & Silver, 1950), which some pieces of equipment seem to ignore.
Attempt to incorporate a variety of exercises and pieces of equipment if available. It has yet to be shown with objective research that one type of resistance exercise is superior to another (Borenstein & Wiesel, 1989).
Another area of concern with trunk exercises is pelvic stabilization to minimize the involvement of the hamstring muscle group during lumbar extensor movements. Without pelvic stabilization, it has been suggested that lumbar extension exercises will allow the hip extensors to perform most of the work (Pollock et al., 1989). Fischer and Houtz (1968) have shown that the hamstrings and gluteals exhibit greater electrical activity than the lumbar extensors in unilateral hip extension performed in the prone-lying position.
The trunk exercises (full range of motion exercises for the lumbar extensors and flexors) should be performed a minimum of two times per week. In addition, strengthening activities for the lower extremities (leg curl for the hamstrings, leg extension for the quadriceps), upper back (rows and lat pulls for the trapezius, latissimus dorsi, and rhomboids) should also be incorporated.
Flexibility exercises to safely stretch the lumbar extensors, hip extensors and hip flexors should be incorporated two or more times per week. Care should be take that these stretches are performed after the body is properly warm-up. (Note: a comprehensive review on flexibility is presented in IDEA Today, June 1993).
The cardiorespiratory guidelines established by the American College of Medicine are appropriate to follow (see ACSM guidelines) for the aerobic exercise prescription. Low impact activities, which avoid ballistic lumbar flexion, are preferred (Foster & Fulton, 1991). Foster and Fulton also indicate the rowing machines should be used cautiously due to persons with disk problems.

Summary
Low back pain is a universal health problem. There is much more to learn from research about its treatment and prevention. As health/fitness educators, you must acknowledge to your clients that there is no cure-all exercise or medicine for this epidemic size problem. However, with an approach towards total body health and fitness, which includes the mind/body connection, you will be employing a most successful theme for possible management, prevention or restoration of healthy back function and quality of life.
Side Bar (Back Illustration with following description)
The spine is made up of 24 vertebrae, cushioned by tough, fibrous, and gelatinous intervetebral discs, arranged in three curves that form a natural S-shape. Your head is supported by the cervical spine. The ribs which protect the internal organs are attached to the thoracic spine. The lumbar spine, which is the site of low back pain and the workhorse of your spine, absorbs nearly all of your torso stress when you stand, sit or move. When the cervical curve, thoracic curve, and lumbar curve are properly aligned, you are less vulnerable to injury and pain.
Side Bar (Causes of Back Pain)
Although not fully understood, low back pain problems are usually linked to two areas: 1) lifestyle, which includes stress, lack of exercise and poor posture, and 2) physical injury or disease. Stress can be a precursor to low back pain by upsetting your nervous system, causing your muscles to go into spasm. Discovering effective coping techniques will not only help you deal better with stress, but relieve or help prevent low back pain. Bending, lifting and twisting movements can all lead to muscle strains and ligament sprains, most likely associated with acute low back pain. The intervetebral discs tend to dry out and degenerate as you age. Poor posture may accelerate this process. Disks losing their shock-absorbing capacity may lead to nerve irritation and injury. Another degenerative health problem associated with age and indicated in low back problems is osteoarthritis.

Side Bar (When Should You See a Doctor)
When back pain or soreness strikes, adhering to proper sitting, standing and sleeping postures is especially critical. Keep your back active, often changing positions when you're standing, sitting, and lying down. This will help distribute the workload to all the muscles of your back. If there is an increase or sustained duration of the pain you may need to see a health care specialist. Consult your physician if the back pain is the result of an impact injury or accident. Back pain that interferes with sleep or daily activities may need professional care. And if you have shooting pains, numbness or weakness in your legs you certainly need to consult your physician.
ACSM Guidelines
Frequency of training 3-5 days per week

Intensity of training 60-90% of maximum heart rate or
50-85% of maximum oxygen uptake or
50-85% of heart rate reserve

Duration of activity 20-60 minutes of continuous aerobic activity

Mode of activity Any activity that uses large muscle groups, can be maintained continuously, and is rhythmical and aerobic in nature

Resistance training Strength training of a moderate intensity, sufficient to develop and maintain fat-free weight should be an integral part of an adult fitness program.
One set of 8-12 repetitions of eight to ten exercises that condition the major muscle groups at least 2 days per week

ACSM. (1990). The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness in healthy adults. Medicine Science and Sports in Exercise, 22, 265-274.

References:
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Biering-Sorenson, F. (1984). Physical measurements as risk indicators for low back trouble over a one-year period. Spine, 9, 106-119.
Borenstein, D. G., & Wiesel, S. W. (1989). Low back pain: Medical diagnosis and comprehensive management. Philadelphia: W.B. Saunders.
Cailliet, R. (1988). Low back pain syndrome, 4th ed. Philadelphia: F.A. Davis Company.
DeVries, H. (1968). EMG fatigue curve in postural muscles. A possible etiology for idiopathic low back pain. American Journal of Physical Medicine, 47, 175-181.
Farfan, H. F. (1975). Muscular mechanism of the lumbar spine and the position of power and efficacy. Orthopaedic Clinics of North American, 6, 135-144.
Fischer, F. J., & Houtz, S. J. (1968). Evaluation of the function of the gluteus maximus muscle. American Journal of Physical Medicine, 47, 182-191.
Floyd, W. F., & Silver, P. H. (1950). Electromyographic study of patterns of activity of the anterior abdominal wall muscles in man. Journal of Anatomy, 84, 132-145.
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Plowman, S. A. (1992). Physical activity, physical fitness, and low back pain. In J. O. Holloszy (Eds.), Exercise and Sport Sciences Reviews (pp. 221-242). Baltimore: Williams & Wilkins.
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Waddell, G. (1987). A new clinical model for the treatment of low-back pain. Spine, 12, 632-644