SPINAL REHABILITATION. (Part 2)
The Requirement for Specific Exercise in Clinical Practice
By Michael N. Fulton, M.D., F.A.A.O.S.

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During the last century, dozens of treatment protocols have been used in attempts to rehabilitate spinal pathology; passive movements, manipulation, immobilization, massage, heat, cold, electrical stimulation, ultra sound and a long list of other treatments; and while some of these protocols apparently do provide at least temporary relief of pain in acute cases, they have never been of much value for treating chronic spinal pain. In no real sense of the word are any of these protocols productive; they cannot provide the stimulus required to produce the tissue changes that are needed for true rehabilitation of chronic spinal pathology.

Which leaves us with only two choices: surgery or exercise. But it has now been clearly established that most of the exercises that have been used for spinal rehabilitation are worthless for their intended purposes. To be effective during spinal rehabilitation the exercise must be specific.

The first exercise machine designed for the purpose of developing the strength of the muscles that extend the lumbar spine was the Nautilus Lower-back machine; initially, while it was obvious that this machine provided exercise for the muscles of the hips and thighs, it was believed that the machine also provided productive exercise for the muscles that extend the lumbar spine. But this proved to be an invalid assumption. Research conducted at the School of Medicine of the University of Florida, Gainesville, has clearly established that such machines will increase the strength of hip and thigh muscles while producing no change in the strength of the lower-back muscles.

People become stronger on the machine, following ten or twelve weeks of such exercise are capable of performing the movements with a higher level of resistance; but it is not the lower-back muscles that are becoming stronger, the benefits of the exercise are limited to the muscles of the hips and thighs; while the strength of the lower-back muscles remains unchanged.

As recently as seven ,years ago, it was impossible to meaningfully test the isolated strength of the muscles that extend the lumbar spine, and thus it was impossible to evaluate the results of an exercise program for these muscles. Earlier testing machines measured the output of torque produced by muscles of the hips, the thighs, and, it was assumed, the lower back; thus it was assumed that an increase in total torque indicated an increase in lower-back strength. but this turned out to be a faulty conclusion.

When it did become possible to perform meaningful tests of the isolated strength of the muscles that extend the lumbar spine it was immediately apparent that most of the exercises being used for the purpose of increasing the strength of the lower-back muscles were worthless for their intended purpose.

Which does not mean that such exercise is worthless for any purpose; the muscles of the buttocks and the rear of the thighs, which work together to move the pelvis in the direction of extension of the back, are certainly important and should not be ignored; but weakness of these muscles is seldom if ever related to spinal pain; the critical muscles in almost all cases of spinal pathology are the muscles that extend the lumbar spine; muscles that can be strengthened only with specific exercise.

Many theories have been proposed in attempts to explain just why lower-back pain is so common, but since none of these theories can be clearly demonstrated I will not engage in speculation on that subject. But at least one thing is obvious: almost all injuries are a result of a structural weakness: when a force is imposed that exceeds the coexisting level of structural strength then something , will fail. And it is also obvious that a meaningful increase in functional strength will also produce an increase in structural strength, thereby reducing the chances of injury.

Proper exercise not only increases functional strength but also increases the size of the muscles, the tendons, the ligaments and the bones; increases in size that produce increases in structural strength.

During the last twenty-five years thousands of studies have been performed for the purpose of determining the best program of exercise for increasing muscular strength. Most of these exercise programs were continued for a period of ten or twelve weeks, with three weekly workouts, and the usual increase in strength was about 25 percent with healthy but previously untrained subjects. The potential for strength increases is obviously determined by the starting level of strength; subjects who are already close to their maximum possible level of strength will not respond to the degree that weaker subjects will. The greatest degree of potential strength increases will be found in subjects who start an exercise program in an atrophied condition.

When it did become possible to perform meaningful tests of the isolated strength of the muscles that extend the lumbar spine, and when specific, isolated exercise for these muscles was provided, the results were surprising: compared to the results produced by exercise programs for other muscles, the following increases in strength were enormous. Rather than the usual result of an increase in strength of about 25 percent, average increases in spinal strength proved to be in excess of 100 percent, and many subjects increased the strength of their lower-back muscles by several hundred percent.

It thus appears that even healthy, pain free subjects clearly demonstrate the effects of chronic disuse atrophy in the muscles that extend the lumbar spine. Chronic patients with spinal pathology are usually even weaker in these muscles when first tested, and thus have an even greater potential for strength increases.

During a medical meeting in New York. "The Challenge of the Lumbar Spine," in 1987. we tested the isolated strength of the lumbar muscles of a man from Philadelphia. The results of that testing procedure established several points: one, the strength of his lower-back muscles was far below average; two, he produced an obviously abnormal strength curve, and repeated the same abnormal curve when retested several hours later; three, a test of his fatigue characteristics clearly established a high percentage of fast-twitch fibers in the lumbar muscles.

Nearly four years later this man visited the School of Medicine in Gainesville and his isolated lower-back strength was tested again. In the meantime he had been performing regular exercise with a Cybex Lower-back machine, and had become very strong , on that machine, and was convinced that his lower-back strength was greatly increased.

But, when retested, we found that his lower-back strength was 22 percent lower than it was nearly four years earlier; and he still had the same abnormal curve of lower-back strength. Obviously, the Cybex exercise did increase the strength of his hip and thigh muscles, but did not prevent a continued loss of lower-back strength.

Tested for a third time about a year later, following another year of exercise with the Cybex machine, his lower-back strength was then unchanged; so the non-specific exercise did nothing for the strength of his lower-back muscles.

I have served as team physician for several teams engaged in water-ski activities for a number of years, and this provided the opportunity to test the isolated lower-back strength of a large number of subjects engaged in this activity. Almost all of these subjects display an abnormal curve of strength of their lower-back muscles; will usually be far above an average level of strength in the more extended part of a full-range movement, but have only an average level of strength in the first part of a full-range movement. And an average level of strength even with normal subjects proved to be very low.

When first tested, this subject's strength in the flexed position was only average for an untrained man, while his strength in the more extended position; was

far above average; static work performed during the preceding thirty-six years of his water-ski activity had produced a very high level of strength in the more extended part of a full range of movement while doing nothing for his strength in the first part of a full-range movement.

Initially we were surprised by the magnitude of strength increases that were produced by specific exercise for lower-back muscles, and then we were surprised again when it became obvious that very little in the way of specific exercise was required to produce such enormous increases in spinal strength. Subsequent clinical experience with thousands of patients with spinal pathology clearly established the fact that isolated exercise for spinal muscles usually should be performed twice each week during the initial stages of rehabilitation, and can frequently be reduced to only once a week after the first six weeks.

Since most exercise programs involve three weekly workouts, and since most of the workouts involve three sets of the exercise (a total of nine weekly exercises for each muscle). we were surprised to find that much less exercise each week was required for increasing the strength of spinal muscles.

So it appears that the lumbar muscles are unique in several respects: usually have the potential for enormous increases in strength, and will produce such increases in strength as a result of very brief and infrequent exercise; provided only that the exercise is specific.

We have also learned that subjects with a high percentage of fast-twitch fibers in their lumbar muscles cannot tolerate either high-repetition exercise or fre quent exercise for these muscles, will rapidly lose strength as a result of overuse atrophy if exercised in that manner. Fortunately, our current testing procedures make it easily possible to identify such subjects; thus the schedule of exercise can be tailored upon a basis of both their individual need for exercise and their tolerance of exercise. A program of exercise that is ideal for a subject with a high percentage of slow-twitch fibers in the lumbar muscles would probably be devastating for a subject with a high percentage of fast-twitch fibers in these muscles, would produce rapid loses in strength rather than gains.

In addition to the now well-established benefits during rehabilitation, specific exercise for lumbar muscles offers enormous potential for the prevention of spinal injury.

The research and development program that eventually produced testing, equipment that was capable of meaningful measurements of true strength and true ranges of motion, as well as specific exercise for lumbar muscles, has been continuously ongoing for more than twenty years and required a total investment now exceeding $83.000,000.00; during the last ten years this research has been conducted in direct cooperation with the School of Medicine of the University of Florida, Gainesville, and for the last two years in cooperation with the Department of Orthopaedics and Rehabilitation at the School of Medicine of the University of California, San Diego.

During the last seven years a team of researchers headed by Michael L. Pollock, PhD, at the School of Medicine in Gainesville, conducted a total of forty-four research programs utilizing this equipment: research involving thousands of subjects, tens of thousands of testing procedures, and hundreds of thousands of exercise sessions.

At the moment, January 1993, 700 patients with chronic spinal pathology are being evaluated and rehabilitated with this equipment every week in San Diego by a team directed by Vert Mooney. M.D.; with outstanding results with more than eighty percent of such chronic patients.

Additional research with thousands of chronic spinal patients has been conducted in several other locations in this country, in Japan and in Europe: with outstanding results in all cases.

And hundreds of thousands of patients with chronic spinal pathology are now being rehabilitated in several hundred clinical facilities in this country, in Canada, in Japan , in Australia , in Korea and in several countries in Europe.

If you are involved in functional testing or rehabilitation you can obtain a free copy of a forthcoming book, "The Lumbar Spine, the Cervical Spine and the Knee," by writing, on your professional stationary. This book covers everything that is currently known on the subjects of functional testing and rehabilitation; all of which information is clearly spelled out and illustrated with color photographs of both testing procedures and test results.

Requests for the free book should be addressed to: MedX Corporation, 1401 NE 77th Street, Ocala, Florida 34479.

Copies of research studies performed in Gainesville can be obtained by writing to:

Dr. Michael L. Pollock, Department of Medicine,

University of Florida , Box J-277, JHMHC,

Gainesville , Florida 32610 .