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Long-term exercise adherence after intensive rehabilitation for chronic low back pain


Medicine & Science in Sports & Exercise: March 2000 - Volume 32 - Issue 3 - p 551-557
CLINICAL SCIENCES: Clinical Investigation

HARTIGAN, C., J. RAINVILLE, J. B. SOBEL, and M. HIPONA. Long-term exercise adherence after intensive rehabilitation for chronic low back pain. Med. Sci. Sports Exerc., Vol. 32, No. 3, pp. 551–557, 2000.

Purpose: The purpose of this study was to examine exercise compliance in patients with chronic low back pain (CLBP) after participation in an intensive spine rehabilitation program.

Methods: Exercise behaviors in 122 consecutive subjects with CLBP who completed a program of quota based exercise were examined. Frequency per week of performance of four exercise activities, Oswestry disability scores, and visual analog scale (VAS) scores were assessed at evaluation, 3-month, and 12-month follow-up by patient-completed questionnaires.

Results: Percentage of patients responding to initial, 3-month, and 12-month questionnaires were 100%, 86%, and 71%, respectively. Frequencies of exercise behaviors were compared by Wilcoxon signed-rank test and were found to increase significantly between evaluation and 3 months (P < 0.000), and evaluation and 12-month follow-up (P < 0.000). The percentages of patients reporting three or more times weekly performance of the following activities at evaluation and at three month follow-up, respectively, were: 1) stretching for the back and legs, 35% and 93%; 2) aerobic exercise, 44% and 87%; 3) back-strengthening exercises, 15% and 82%; and, 4) weight training, 6% and 71%. Evaluation and follow-up Oswestry disability and visual analog scale (VAS) scores for back pain were compared using Student’s t-test. Significant improvements (P < 0.000) were noted for each of these scales at 3-month follow-up that were maintained at 12-month follow-up.

Conclusion: It is concluded that exercise behaviors can be increased and maintained in CLBP patients without adversely affecting pain or function.

The Department of Rehabilitation Medicine, Tufts University School of Medicine, Boston, MA

Submitted for publication September 1997.

Accepted for publication January 1999.

Address for correspondence: Carol Hartigan, M.D., The Spine Service, New England Baptist Bone and Joint Institute, 125 Parker Hill Avenue, Boston, MA 02120. E-mail:

Most patients with chronic low back pain (CLBP) associate strenuous physical activities with increased pain (34) and avoid activities believed to produce discomfort. Indeed, patients with CLBP are known to be inactive as measured by numerous life function and disability scales and significant levels of physical deconditioning have been documented in this population (1,7,16,17,19,20,23,26). Level of reported pain is known to be affected by numerous nonphysical factors (3,4,6,12,38,43) and is therefore not a reliable or valid measure on which to base activity recommendations. Additionally, significant improvements in physical performance can be achieved in patients with CLBP in spite of continued pain symptoms (35). Nevertheless, health care providers remain reluctant to advise resumption of activities, and frequently reduce therapeutic activity goals in this population due to reports of pain. This may contribute to an unnecessary sedentary state that increases the risk for poor health as well as premature mortality in this population (31,32,40).

Intensive rehabilitation programs for patients with CLBP incorporate progressive training in endurance, flexibility, and strength in order to reverse deconditioning and improve life function. Therapeutic treatment goals are not dependent on level of reported pain, and behavioral techniques are employed to provide positive reinforcement for physical and functional progress. In addition to significant long-lasting improvements in physical parameters in this population after such treatment, improved life function and reduced levels of pain have been demonstrated (13,21,35,37,39).

Unfortunately, whether CLBP patients continue to perform all or part of cardiovascular and back-conditioning regimens after discharge from intensive treatment is infrequently reported. One study reported that 53% of patients with CLBP had “used” a simple elastic gym exercise device 13 months after treatment with intensive, specific exercise, but the frequency of use was not reported (29). Whether post-treatment endurance exercise was recommended or performed was not reported. In another study, only 46% of patients with CLBP continued to perform flexibility exercises 2 months after exercise treatment (9).

Most physicians do not provide physical activity advice to their patients, and only a minority provide exercise prescriptions (14,46). Sometimes supervised exercise programs are prescribed for particular medical reasons, including musculoskeletal and cardiovascular rehabilitation, weight reduction, diabetes control, osteoporosis prevention, and general health. However, investigators have documented poor compliance for both participation in these advised programs and for performance of recommended post-treatment exercise regimens (2,27,29,32,43,44). It seems irrational to provide such expensive exercise treatments if no significant change in exercise habits results. Therefore, when populations undergo exercise treatment, regardless of the diagnoses, attention to exercise-adherence outcomes and identification of factors affecting adherence after treatment seems warranted.

The purpose of this study was to examine exercise compliance in patients with CLBP after participation in an intensive spine rehabilitation program. Specific questions included: 1) Does the frequency per week of performing back stretching, back-strengthening exercise, aerobic exercise, and weight training increase compared with pretreatment levels after aggressive treatment for chronic back pain? 2) If so, are these changes maintained at 12-month follow-up? 3) Does the frequency of exercise at evaluation correlate with other variables? 4) Is the frequency of exercise reported at 12-month follow-up influenced by the intensity of pain and disability noted at 12-month follow-up, or by the changes in pain, disability, and physical performance ability that were observed following completion of rehabilitation (3-month follow-up)?

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Consecutive patients with primary complaints of chronic (duration > 4 months) low back pain and/or sciatica evaluated by physicians at a spine rehabilitation center between October 1, 1993, and February 28, 1994, were entered into a prospective data base if they: 1) were between the age of 18 and 70; 2) had no surgically correctable lesion as the cause of low back pain (or were not interested in pursuing surgical options); 3) were at least 3 months post discectomy or 6 months post fusion; 4) possessed reading and writing comprehension of the English language in order to complete self-assessment measures; and 5) had no concurrent medical illness (cardiopulmonary, central nervous system, etc.) that produced significant disability. Eighty-seven percent of patients were referred by physicians or medical case managers, and the remainder were self-referred. Patients underwent standard treatment provided at clinic, and written informed consent for this observational study of usual treatment and outcomes was not obtained from patients.

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Self-assessment measures.

All patients completed a questionnaire that inquired about demographic variables, symptoms, past diagnostic tests, past treatments, compensation involvement, and work status. These items were reviewed and verified during the physician evaluation.

Exercise was assessed with a brief questionnaire that inquired about how regularly subjects performed exercise activities. Four exercise activities were assessed and included: 1) stretching for your back and legs; 2) lifting weights; 3) performing back strengthening exercises; and 4) aerobic exercise (walking, running, bicycling, aerobics, etc.). Responses to these exercise questions were recorded as the frequency of exercise, with subjects choosing 0, 1, 2, 3, 4, or 5 or more times per week. Intensity of exercise behaviors was not measured, and the frequency of exercise activities was not confirmed by the report of others or review of attendance records from exercise facilities.

Self-reported disability was measured by patients completing an Oswestry Disability Questionnaire (OSWESTRY) with potential scores ranging from 0 (no disability) to 100 (severe disability) (10). The intensity of pain was measured by a 10-cm visual analog scales (VAS) anchored with 0 (no pain) and 10 (worst possible pain) for back (BACK-VAS) and leg (LEG-VAS) pain symptoms (11).

Three months after the evaluation by the physician, a research assistant mailed a follow-up packet to all patients. Packets included an exercise questionnaire, OSWESTRY, BACK-VAS, LEG-VAS, and a stamped return envelope. If no response was received in 3 wk, a second packet was mailed. After 3 more weeks, phone calls (maximum of three) were placed to all nonresponding subjects. If contacted, subjects were given the options to answer questions over the phone or complete the mailed questionnaire. When not at home, instructions were left with household members or on answering machines to contact the research assistant or to complete the mailed questionnaires.

Twelve months after the initial evaluation, another follow-up questionnaire was mailed to subjects that included all of the above-mentioned components. The procedure for mailing and phone calls as detailed above was used.

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Quantification of physical function.

Trunk flexibility, straight leg raising, trunk strength, lifting ability, and lower extremity work endurance were quantified for all subjects who received physical therapy at initial evaluation and at the completion of treatment.

Maximum trunk range of motion for flexion and extension in the standing posture was measured with a single inclinometer (AngleLevel, Dejon Tool Co., Covington, OH) placed over the T-12 spinous process (36). Maximum straight leg raising (SLR) was measured by placing the inclinometer over the bony surface just below the tibial tuberosity and raising the leg until significant back or leg pain occurred or the pelvis was observed to rotate (16,22).

Trunk extension strength was quantified using Cybex Eagle back extension exercise equipment (Lumex Corp., Ronkonkoma, NY). The test procedure consisted of a four-repetition to maximum weight lifted protocol (42). The results of the test were recorded as the maximum weight successfully lifted for four repetitions.

Lifting ability was evaluated using the Progressive Isoinertial Lifting Evaluation (PILE) described by Mayer et al. (22). The maximum weight lifted for four repetitions from floor to waist was recorded as lumbar PILE and from waist to shoulder as cervical PILE.

To correct for anthropomorphic differences between subjects, maximum back strength and PILE weights were converted into percent ideal body weight before data analysis. Ideal body weight was calculated for subjects by measuring height and actual weight and estimating body type. By using standardized, sex-specific charts, the ideal body weight was calculated (27).

Lower extremity work performance was quantified using a 9-min protocol on an isokinetic exercise bicycle (Cybex Fitron, Lumex Corp.). Results were calculated by totaling the kg·m generated during a 9-min testing protocol (42).

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Rehabilitation included advice from the evaluating physician about the potential benefits of improving back function and an explanation that pain with activities did not usually indicate harm. Exercises to improve back function were recommended, and referrals to physical therapy were made for the development of these exercise programs. Physical therapy services focused on eliminating impairments in flexibility, trunk strength, endurance, and lifting capacity through active stretching and exercise. Impairments were identified with testing as described above. Exercises and stretches were initiated at intensities submaximal to the measured physiological limit with graded increases in intensities prescribed. The occurrence of pain with exercises was expected, and patients were encouraged to work through pain symptoms in order to complete the established exercise quota. Physical therapy treatments other than exercise were not offered. Nonsteroidal anti-inflammatory and antidepressant medications were prescribed per the discretion of the evaluating physician, but narcotic analgesics were not, and their use was discouraged. Referrals for psychological counseling were occasionally requested.

Subjects with high levels of chronic pain (Back VAS > 5) and significant pain-related disability (Oswestry Disability Scores > 30) were referred into a spine rehabilitation program. This program consisted of a maximum of eight subjects and was led by a physical therapist and an exercise physiologist. After three sessions for evaluation and orientation, subjects attended 2-h sessions, three times per week for 2 wk. This was followed by 2-h 45-min sessions, three times per week for 5 wk. The total program time was 8 wk.

Sessions included stretching, strengthening, and endurance training. Strengthening equipment included Cybex Eagle Strength System (Lumex Corp.) back extension, rotary torso, multi-hip and lat pull down machines, Roman chair (back “hyperextension”), PILE lifting station, free weights, and Theraband. Endurance equipment included isokinetic bicycles (Cybex Fitron, Lumex Corp.), upper body ergometer (Cybex UBE, Lumex Corp.), and low-impact step aerobics.

Exercises for all patients were uniform throughout treatment but were prescribed at individualized intensities. Initial strength, lifting, and endurance exercise training levels for each patient were based on that patient’s initial (4-repetition maximum) evaluation test results and were set at 65% of the resistance achieved on the test. Initial training intensities for exercises and equipment that were not tested were based on performance ratios reported in the literature (26) and observed in our clinic. For example, ratio of training resistance for back extension to rotary torso machine was 2 to 1. Subsequent training intensities for each patient were increased based on quotas determined weekly. Quotas were based on requantified trunk flexion, extension, SLR, back strength, PILE, and lower extremity work capacity, which was performed for all patients biweekly and at the completion of treatment. Carotid pulse rates were monitored throughout endurance training. Heart rate limits were set for subjects by their physician if they were over 45 yr old or had significant cardiac risk factors. Compliance, complications, behavioral problems, and treatment goals were discussed at biweekly team conferences between therapists and physicians. Patients were encouraged to complete exercise quotas even in the setting of low back pain. Behavioral techniques were used to promote wellness behaviors (exercise) and extinguish pain behaviors (limping, moaning, declining to perform exercises, etc.). Positive reinforcement (praise) was given to patients for successfully completing exercise quotas and increasing home and community level functional status.

Subjects with low levels of chronic pain (Back VAS < 5) and disability (Oswestry Disability Score < 30) were referred for individual physical therapy. Similar treatment approaches and goals were used for these treatments; however, sessions averaged 45 min each and occurred at a frequency of one or two session per week. Therapy sessions combined supervised performance of recommended exercise with instructions regarding form, technique, expected rate of progression and frequency of performance. Subjects performed the majority of exercises unsupervised at home or in fitness facilities. Most subjects were independent with all recommended exercises and were discharged after 4 wk of individual physical therapy.

At discharge, all subjects (from both groups) received individualized, written recommendations concerning exercise routines to be performed at home and/or at a fitness facility. In general, it was recommended that stretching be performed at least once daily, aerobic and back-strengthening exercises performed three or more times per week, and weight-training exercises performed three times per week.

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Statistical methods.

Statistical analyses were performed using SPSS statistical software for personal computers (SPSS, Chicago, IL). Wilcoxon sign-rank tests were used to compare the frequencies of initial exercise behaviors with those behaviors at 3- and 12-month follow-up. Paired-sample t-tests were used to compare OSWESTRY, LEG-VAS, and BACK-VAS at evaluation with 3- and 12-month follow-up and physical function measurements at evaluation and at completion of treatment. Analysis of variance (ANOVA) was used to compare frequency of exercise between subjects based on treatment and compliance.

Multiple correlations and analysis of variance models were performed to search for variables, which might explain the frequencies of exercise behaviors at evaluation and 1-yr follow-up.

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A total of 192 subjects fulfilled all entry requirements. Thirty-eight subjects were evaluated only and did not receive any rehabilitation intervention. Thirty-two subjects were referred for rehabilitation but were uninterested or unable to comply with recommended treatment due to lack of insurance authorization.

A total of 122 subjects were referred for and complied with rehabilitation recommendation. This included 85 subjects who completed the spine rehabilitation program and 37 subjects who received individual physical therapy services. These subjects will be the focus of this paper.

The mean age was 41 yr, duration of symptoms was 49 months, and education was 15 yr. Forty-nine percent of subjects were female, and 31% had failed prior back surgery. Twenty-nine percent had workers’ compensation involvement with their pain symptoms, and 34% were disabled from work. Sixty-four percent had received prior physical therapy services and 34% prior chiropractic treatments.

Eighty-six percent of subjects responded to 3-month questionnaires and 71% to 12-month questionnaires.

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Pretreatment exercise frequency.

Frequency per week of exercising for all subjects before evaluation is reported in Table 1. ANOVA revealed that subjects who dropped out of treatment performed back exercises more frequently before treatment than subjects who were evaluated only and those who complied with individual or group therapy (F = 5.3, df 3, P < 0.01). Weekly performance of prior stretching and aerobic and weight lifting exercises did not differ between subjects evaluated only, those dropping out of treatment, or those complying with recommended rehabilitation. At evaluation, OSWESTRY, BACK-VAS, LEG-VAS, age, sex, disability status, compensation involvement, education, duration of pain, initial range of motion, strength, and lower extremity work capacity did not correlate with the weekly frequency of any of the surveyed exercises. Prior physical therapy produced a trend toward increased frequency of back exercises and stretching, but this did not reach significance. This trend was not present for aerobic or weight-training exercise frequency.

Table 1

Table 1

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Exercise frequency after physical therapy.

For subjects complying with treatment, the frequency per week of exercising increased significantly at 3 and at 12 months follow-up. Analyses with Wilcoxon matched pairs sign-ranked test revealed that the increases in exercise frequencies between evaluation and 3-month and evaluation and 12-month follow-up reached statistical significance for all types of exercising, with P-values less than 0.000. Though a slight drop in exercise frequency was noted between 3 and 12 months, these did not reach statistical significance. Exercise frequency reported for those treated with the group rehabilitation program and individual physical therapy were clinically and statistically similar and are therefore combined and presented in Table 2.

Table 2

Table 2

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Subjective and objective outcomes.

Improvement was noted when comparing pre- and post-treatment flexibility, back strength, lifting ability, and lower-extremity work performance. These values are presented in Table 3. Improvements were also noted in BACK-VAS and OSWESTRY scores at evaluation and 3-month follow-up. These were maintained at 12-month follow-up. These are presented in Table 4.

Table 3

Table 3

Table 4

Table 4

Correlations and multifactorial ANOVA equations developed to explore variables, which might explain differences in exercise frequency of subjects at 12 months revealed that frequency of exercises in one category correlated positively with exercise frequencies in other categories, suggesting a trend to perform or avoid all exercises with similar frequency. Final measures on physical tests, percentage changes for physical tests, 12-month OSWESTRY, BACK-VAS, and LEG-VAS scores, percentage changes for OSWESTRY, BACK-VAS, and LEG-VAS scores, age, education, sex, prior spine surgery, workers’ compensation involvement, and duration of treatment did not correlate with different frequencies of exercising.

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This study demonstrated significant changes in reported exercise behaviors in a group of patients with CLBP after functionally oriented rehabilitation. Compliance was noted for a majority of patients with recommendations for stretching, back strengthening, weight lifting, and cardiovascular fitness training and improvements in reported exercise behaviors persisted at 1-yr follow-up.

We were not able to identify factors that definitely changed or reinforced these exercise behaviors. It is unlikely that recommending exercise alone led to a change in adherence. A recent study demonstrated that merely providing an exercise prescription, even if endurance equipment is provided for home use, is unlikely to produce a change in exercise habits (8). Further, poor exercise adherence has been noted even after supervised exercise programs (2,5,28,30,33,44,45).

Among potential factors affecting adherence to exercise noted in this study was our requirement that quantifiable progress be made in exercise performance during treatment, which guaranteed that improvements in physical performance would occur for all patients. Additionally, patients were expected to independently adjust equipment and perform exercises during supervised sessions. This requirement provided patients with an opportunity to practice and master exercise techniques. Both of these requirements may have reduced patients’ perception of helplessness regarding exercise while reinforcing their perception of “self-efficacy” for exercise. Indeed, a recent study identified lower levels of “helplessness” as relating to exercise compliance (41). Other work has demonstrated that improved exercise compliance can be predicted for individuals who report greater perceptions of self-efficacy for exercise (24,25).

The conveyance to patients in our study that the treating physician and therapists believed in the patients’ capacity to perform recommended exercises in spite of pain symptoms may have helped to reinforce a sense of capability in patients for continued exercise performance. McAuley et al. (25) have reported that patients receiving maximum information regarding their exercise capability are more likely to adhere to recommended exercise programs than those who do not receive such information. Additionally, positive feedback for successful completion of exercises and for progress made in treatment may also have had an effect on adherence to exercise. Lack of positive feedback has been identified as a factor related to noncompliance with exercise (41).

Even though patients were expected and advised to continue to perform exercise and life activities during episodes of increased pain, they reported significantly less pain and disability at post-treatment and 1-yr follow-up compared with initial evaluation. This approach gave patients an opportunity to experience success at making physical and functional progress during exacerbations of pain not merely without adverse effect but with beneficial effect on pain symptoms. Because of this, our patients may have experienced a change in attitudes and beliefs regarding the advisability of exercise in the setting of low back pain. Indeed, patients’ belief systems have been shown to correlate with exercise regimen cooperation (15).

Additionally, in our study, if patients complained of a severe exacerbation of pain, physician reevaluation and determination regarding “safety” of symptoms was performed, and patients could be cleared for resumption of therapy if indicated. The communication between the treating physician and therapist after such episodes may have prevented the imposition of unnecessary therapeutic limitations or discontinuation of treatment “due to pain” with suboptimal outcome.

Patients’ perception of barriers to exercise adherence was identified in a recent study as a primary factor related to noncompliance with exercise (41). In our cohort, a formal, realistic, post-treatment exercise “prescription” was developed individually with each of the patients in the final weeks of treatment. Patients were advised to perform several trial exercise sessions at the unsupervised post-treatment exercise site before discharge so that any necessary modifications in recommendations could be made and so that transition to independent performance would not be abrupt. We also provided focused coaching of and problem solving for those of our patients who reported more significant barriers to adherence. For each patient goals included creating an adequate, realistic, low tech, low cost, minimally time-consuming post-treatment maintenance regimen. This support and encouragement at overcoming barriers as well as the prescribed transition to independent exercise may have affected adherence outcome.

Weaknesses of this study include the prospective observational design. Patients choosing to undergo exercise treatment may have been ready to make a change in exercise habits. Patients dropping out of or declining treatment may have been uninterested in changing exercise behaviors or may have had medicolegal or psychosocial issues creating a disincentive to change either exercise behaviors or functional status.

Another weakness of this study is that exercise behaviors are self-reported and may not accurately reflect true exercise behaviors (18). No attempts were made to confirm exercise reports at follow-up, such as performing flexibility, strength or endurance tests, or by checking health club attendance records. Further, the treatment group was aware of the bias of the treating clinicians regarding exercise. Although patient surveys were anonymous, treated patients may have been inclined to exaggerate exercise behaviors at follow-up to please the follow-up reviewers.

Several important implications can be made based on the results of this study, regardless of the weaknesses. First, exercise behaviors can be increased in CLBP patients after aggressive rehabilitation in addition to improvements in physically measured back function and subjectively reported life function. Second, performing regular exercise does not have an adverse affect on pain in this population. Third, the generally recognized benefits of regular exercise can also be enjoyed by CLBP patients. Future studies on therapeutic interventions for benign CLBP and other musculoskeletal symptoms should include exercise-adherence outcomes.

Presented at the International Society for the study of the Lumbar Spine, Annual Meeting, Burlington, VT, June 1996.

Current address for James Rainville, M.D., and Mark Hipona, B.S.: The Spine Service, New England Baptist Bone and Joint Institute, 125 Parker Hill Avenue, Boston, MA 02120.

Current address for Jerry B. Sobel, M.D.: S.O.A.R., The Physiatry Medical Group, 2884 Sand Hill Road, Suite 110, Menlo Park, CA 94025.

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