A Clinical Trial. Exercises for Chronic Low Back Pain:

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Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at on January 15, 2017. For personal use only. No other uses without permission. Copyright © 1995 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.

Exercises for Chronic Low Back Pain: A Clinical Trial Finn )ohannsen, MD' lars Remvig, Dr2 Peter Kryger, Dr3 Peter Beck, MD4 Susan Warming, PT5 Kirsten 1ybeck, PT6 Vivi Dreyer, PT7 lone H. larsen, PT'

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ow back pain (LRP) is a major socioeconomic problem in the western world (3,14,25), and considerable effort has been put into identifying risk factors (39). Many studies have found that inadequate strength and endurance of the back muscles are significant risk factors (1,3,2l); physical training programs have been prescribed as therapy. Many different kinds of training programs have improved function and pain levels in patients with chronic low back pain (9,11,12,22,23, 28,37,38). Williams' flexion exercises have been a cornerstone in the management of LBP patient? for many years (44). However, these exercises were somewhat discredited when Nachemson showed that they significantly raised the intradiscal pressure (34). Instead, isometric exercises were advocated (22). Later, extension exercises gained popularity, especially after McKenzie showed that they had a beneficial effect on recurrent low back pain (30). However, other studies have not found any effect of isometric o r dynamic back exercises compared with placebo ultrasound (29) o r short-wave diathermy (7). In a recent review, it is concluded that no consensus can be made about

Different training models are effective for the treatment of chronic low back pain, but no consensus has been found. Earlier studies have emphasized training of spinal mobility and back strength. To evaluate if other physiological parameters, such as coordination, are of equal importance, we performed a randomized trial on 40 consecutive patients with chronic low back pain. Two training models were compared: I ) intensive training of muscle endurance and 2) muscle training, including coordination. In both groups, training was performed I hour hvice a week for 3 months. Pain score, disability score, and spinal mobility improved in both training groups without differences between the two groups. Only intensive training of muscle endurance improved isokinetic back muscle strength. At study entry, we found a significant correlation between spinal mobility and dysfunction, but after the training, no correlation was found between improvement of spinal mobility or isokinetic back extension strength and improvement of function or pain level. We conclude that coordination training for patients with chronic low back pain is as equally effective as endurance training.

Key Words: low back pain, muscle strength and endurance, coordination, proprioception

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Doctor, Department of Rheumatology, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke, 2400 Kobenhavn NV, Denmark Supreme Doctor, Department of Rheumatology, Koge Hospital, Roskilde amt, Denmark Supreme Doctor, Department of Rheumatology, Hvidovre Hospital, University of Copenhagen, Denmark Supreme Doctor, Department of Rheumatology, Frederiksberg Hospital, University of Copenhagen, Denmark 5-8 Physical Therapist, Department of Rheumatology, Bispebjerg Hospital, University of Copenhagen, Denmark

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whether exercise therapy is better than other conservative treatments for back pain or whether a specific type of exercise is most effective (24). Optimal muscle function does not depend upon muscle strength/ endurance and muscle flexibility only. The coordination of movement? is also of great importance. When unfamiliar and complicated movement? are performed, they are executed clumsily and with difficulty.

With proper practice/training, they become smooth and easy (2). Specific coordinated reflexes p d u a l l y develop through training of specific movements. This is called coordination training and does not necessarily increase muscle cross-sectional area (muscle strength) (2). Coordination training is essential to increase performance in many sports and is also used with success in the prevention of injuries (43). Strength or endurVolume 22 Number 2 e August 19% JOSPT

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ance training alone will primarily improve the specific movements trained. However, everyday life consists of a wide spectrum of different movements of the back, including rotation and sidebending in different degrees of back flexion and extension. Therefore, it appears logical to train the coordination/propriocep tion of patients with LBP in as many different movements as possible with limited and controlled load. Thereby, coordinated reflexes will develop and the movements will become smooth, which might decrease the risk of I* cally harmful stress forces.

pain for at 1ea.t 3 months in the last year, but were still employed. Those with signs of nerve root compression or evidence of spondylolisthesis, osteoporosis, painful osteoarthritis in the lower extremities, inflammatory rheumatic diseases, and neoplastic disorders were excluded. X-rays of the lumbar spine were performed before inclusion. The X-rays were evaluated by a trained radiologist. with special attention to the exclusion criteria, disc degeneration, facet joint arthrosis, spondylarthrosis, and Morbus Scheuermann.

Procedure

When unfamiliar and complicated movements are performed, they are executed clumsily and with difficulty. Many studies have focused on training of muscle strength/endurance and/or mobility (9,11,12,22,23, 28,37,38), but we have found no studies evaluating the effect of coordination training. Therefore, we compared coordination training with intensive muscle endurance training, which is a recommended treatment for low back pain today (28.37).

MATERIALS AND METHODS Subjects Forty consecutive patients were included in this study after informed consent. All patients were admitted to the Department of Rheumatology, Bispebjerg Hospital, Copenhagen, Denmark under the diagnosis of chronic low back pain. Eligibility was confined to patients aged 18-65 years with low back pain for more than 1 year. The patients had back JOSFT Volume 22 Number 2 August 1W5

All included patients were randomized by stratification for sex, age (older/younger than 40 years), duration of symptoms (greater/less than 2 years), and normal/abnormal X-ray into two training models: endurance training and coordination training. The patient. were trained in groups of up to 10 patients for 1 hour twice a week during a Smonth period. Patients with more than 30% absence from training were excluded from the study. After the 3 months of supervised training, the patient5 were encouraged to continue exercises at home. This was not controlled.

Endurance Training Each session started with 10 minutes of warming up on a bicycle. Dynamic exercises emphaqizing muscle endurance were performed for the low back muscles (Figures 1 and 2), abdominal muscles (Figure 3), muscles around the shoulder girdle (Figure 4). and also the hip abductors, hip adductors, and knee extensors. All movements were strictly controlled by strap fixation and physical therapist supervision. The patients were encouraged to do the greatest possible extension in the hips and spine, disregarding pain. Combined movements and rotations were not allowed. Each patient did as many repetitions of each exercise as possi-

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FIGURE 1. Endurance training. leg lifting. Standing by the end of the couch, lean over to a prone position with the hips against the edge in 90" ilexion, knees 454 and feet on the floor. If necessary, chest is fixated to the couch by strap fixation. Both legs are lifted to the greatest possible extension in hips and spine. A physiotherapist controlled that the legs moved symmetrically.

FIGURE 2. Endurance training. Trunk lihing. Prone on a couch, hips at the edge, upper part o l the body free but supported by the hands against the floor. Strap fixation over the calves. With hands on the head, the trunk is lifted straight up to the greatest possible extension in hips and spine.

FIGURE 3. Endurance training. Abdominal contractions. Supine crook lying. Knees flexed, feet flat on the couch without fixation. With arms on the head, slow sit-up exercises were performed straight forward.

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FIGURE 5. Coordin,ttion tr,tinin,q. St.trtin,q in ,I ~;r,~ndiny: podion, thc l o w r 11,td is ror,ttrd to thr ri,qht and the upper hack to the left while doing active ilevion exercises in the lefi upper extremitv and right lower extremitv. Aiter touching the knee with the elbow, go back to the standing position with straight legs, arms, and hack. The exercise is alternately performed with the left elbow touching the right knee and the right elbow touching the left knee.

FIGURE 4. Endurance training. Pull to neck. Sining on a bench with the arms straight and abducted over the head and hands grasping a weight lever. The lever is pulled down behind the neck and shoulders with submaximal load.

ercises than the other group. Combined movements and rotations were emphasized without fixation. All exercises were performed within a limited range of motion, respecting each patient's pain limits. After each session, 10 minutes of stretching of the trained muscle groups were performed using static stretching for 30 seconds.

Evaluation ble up to 100, with 30-second pauses per 10 repetitions. As training was limited to 1 hour per training session, it was onlv possible to perform approximately four different exercises (Figures 1-4) when 100 repetitions were reached. After each session, 10 minutes of stretching of the trained muscle groups were performed ming static stretching for 30 seconds.

All patients were evaluated bv the same two rmhlinded observers at entry, after 3 months of training, and 6 months after entry. Isokinetic muscle strength doing hack extension and hack flexion was tested using a Kin-

Com I1 (Chattecx Corp., Hixson, TN). T h e Kin-Com tnmk testing svstern is shown to be very accilrate in testing strength gains irrespective of the training methods used (42). Patients were positioned as described by Smidt et al (42) in a sitting position with 90" flexion in the hips and knees and with the pelvis and legs fixated. The resistance was placed on the upper part of the sternum while measuring flexion strength and just below the spine of the scapula while measuring extension strength. Recause LRP patient5 normally have limited range of motion, we measured muscle strength in a 20" range of motion of the trunk. An ini-

Coordination Training Each session started with 10 minutes of warming u p on the floor, including jogging. Exercises emphasizing coordination, balance, and stability were performed for the low back, shoulder, and hip (Figures -5-8).Each patient did u p to 40 repetitions of each exercise; it was possible to perform a wider variety of ex-

FIGURE 6. Coordination training. Positionedon the floor with both knees, hips, andshoulders flexed 90". The right leg is extended to 0' in the knee and the hip, and the left arm is flexed to 180°. Rack to the starting position, and then the exercise is repeated with the opposite extremities.

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FIGURE 7. Coordination training. Supine crook Iving with knees f l e x 4 and feet flat on the floor. Sit-up exercises with rotation of the back alternatelv to the k i t and to the right.

tial torque overshoot is often seen in isokinetic dynamometn. This is an artifact not to be confi~sedwith tnle muscular tension development (41 ). Therefore, we truncated 3" of the cunre at the start of the trunk motion. Total work expressed by area under the isokinetic strength curve was chosen as it was found to be the most reliable measure of isokinetic muscle strength (42). An average of three tests with slow angular velocities (IOO/sec,20°/sec, and 30°/sec, respectivelv) was calculated, as the reliability increases with slower testing speeds (8).

I,ow hack pain patients are forlnd to have reduced spinal mobility (32). T h e sum of lateral flexion to both sides measured with a tape as the distance the hand moves down the leg during maximal lateral bending has the best association with LRP (32). This method is reliable (31) and has been used in earlier studies on this patient group (38). However, lateral flexion is not forlnd to significantlv improve during a training program of flexion exercises and/or extension exercises for LRP patients (38). These training methods significantlv improved the flexion measured as

FIGURE 8. Coordination training. Proprioceptive training on an ankle disk with a spherical undersudace. Try to keep I)abnced while twistin,q and knee bending, standing on both ieet at the beginning and later on one leg at a time.

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the fingertipfloor distance during maximal fonvard bending (38). Forward and lateral flexion of the lumbar spine increases with lumbar lordosis, but extension decreases. T h e opposite is seen with increased thoracal kyphosis. Rv summing flexion and extension, the biasing effect of lordosis o r kyphosis is reduced (32). Therefore, we chose to measure lateral flexion to both sides, flexion and extension, and calculate a mobility score bv addition of the four measures in centimeters. Flexion was measured using the modified Schober test as described by Macrae and Wright, who found this measure reliable (26). Lateral flexion was measured in standing position doing maximal lateral flexion in the frontal plane as described bv Ponte et al (38) and reliability tested by Mellin (31). We measured the fingertipknee joint distance. If the fingertips were above the knee joint, negative values were measured. Extension was measured by sternal elevation (couchjugulum distance) while doing s u p ported active extension lying prone. Therebv, we found it unnecessaq to fixate the pelvis as it was forced into the couch. This testing method is not as vet validated. Rack pain at the time of evaluation was registered on a .?point scale (0-4). Average back pain in the last week was registered on a similar .?point scale. A pain score was calculated by addition of these two scales. A similar method is used in the Claus Manniche Low Rack Pain Rating Scale (27). Disability was estimated by asking whether the patients felt impaired (1 point) o r not (0 point) in doing 12 evendav activities (dressing, rising from a chair withoi~tusing the arms, washing up, cleaning, shopping, driving a car, bicycling, bus riding, stair climbing, walking, sleeping, and normal sexual activities). These activities are common activities to all Danish adults, and they were chosen as o u r clinical experience has shown that they were descriptive of Danish

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chronic low back pain patients. The number of impaired activities was recorded as a disability score (0-12). A similar method is used in the Claus Manniche Low Back Pain Rating Scale (27). Drug consumption was registered by counting number of patient. using weak analgesics [paracetamol, nonsteroid anti-inflammatory drugs (NSAID), acetyl salicyl acid (ASA)] or strong analgesics (opiates) regularly. The number of days on sick leave in the last year before study entry and during the study wa. also registered. The classical way of measuring treatment outcome is the patient's overall assessment, meamred on a box scale by asking about their general well-being (19). In our study, we used a %point scale (1 = good, 3 = bad), and, in order to analyze differences between the two treatment groups, the number of patients improved, worsened, or unchanged during the study was calculated.

Data Analysis The Wilcoxon-Pratt test was used to analyze changes in scores within groups and the Mann-Whitney test or Fisher's exact test was used to analyze changes between groups. The Spearman test was used for correlation analysis. The level of significance was chosen at jK0.05 a pn'ori. Results are given as the median with 12.5 percentiles.

Forty patients participated in this study. Thirteen out of 20 accomplished 3 months of endurance training. Fourteen out of 20 accomplished 3 months of coordination training. The entry characteristics of the patient. who accomplished the trial are shown in Table 1. These two groups were found to be comparable. Altogether, 13 patients dropped out for various reasons. These 13 patients had an average of 134 days (range = 30-335) of sick leave due to back

Endurance ~ r a & n ~ N Median

12.5 Percentile

Coordination Training N Median

12.5 Percentile

Number of patients Number of women Age (years) Weight (kg) Height (cm) Disability days due to back pain in the last 12 months Patient's general assessment (0-3) Pain score (0-8) Mobility score (cm) Disability score (0-1 2) lsokinetic back extension strength (Nm) lsokinetic back flexion strength (Nm) No differences between these two groups were found.

TABLE 1. Entry characteristics of patients who accomplishedthe trial (median and 12.5 percentiles).

pain within the last 12 months before study entry. The same figures for the patients who accomplished the training were an average 35 days (range = 8-215 days). This is a significant difference (jK0.05, Mann-Whitney). Seventy-nine percent (22/28) of the patients with less than 120 sick leave days within the last year accomplished the training, but only 42% (5/12) of the patients with more than 120 sick leave days within the laqt year accomplished the training. Otherwise, no significant differences were found between patients who dropped out and patients who accomplished the trial. The reasons for the seven d r o p outq from the group that endurance trained were increased pain (N=4), lack of time (N=2), and general fatigue (N= 1). The reasons for the six dropout. from the group that coordination trained were increaqed pain (N=2), lack of time (N=l), dyspepsia (N= 1). social reasons (N= 1), and the start of other treatment (N= 1). After 3 months of training, both training groups showed significant improvement in pain score, mobility score, and disability score (Table 2). These improvements were still significant at the follow-up control after 6 months (Table 2). No differences, however, could be found between the

two training groups with respect to these parameters. Also, in overall assessment, no difference was found between the two groups (p= 1.00, Fisher). Drug consumption was reduced to almost one-third in both treatment groups without any differences between groups. Isokinetic back extension strength improved significantly in the endurance trained group, but otherwise no significant changes in isokinetic strength was found within or between groups during the training period (Table 2). At follow-up after 6 months, isokinetic back extension strength was still significantly improved for the endurance trained group compared with the strength assessment at entry. For the coordination trained group, a significant increase in both isokinetic back extension and back flexion strength was noted at follow-up compared with the entry assessments. Correlation analysis between the subjective parameters (pain score, disability score) and the objective parameters (mobility score, back extension strength) showed significant negative correlation between mobility score and disability score pretrial (p=0.009, R(S) = -0.425, Spearman). Otherwise, no correlations were found. Volume 22 Number 2 August 1095 JOSPT

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3 Months

At Entry

Assessed Parameter

Median

Pain score (0-8)

Endurance training Coordination training

Mobility score (cm)

Endurance training Coordination training

Disability score (0-1 2)

Endurance training Coordination training

lsokinetic back extension strength (Nm)

Endurance training Coordination training

lsokinetic back flexion strength (Nm)

Endurance training Coordination training

12.5 Percentile

Median

12.5Percentile

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6 Months (Follow-up) Median

12.5Percentile

* Significant improvement compared with the assessment at entry, p

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