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Pilates-Based Therapeutic Exercise: Effecton Subjects With Nonspecific Chronic LowBack Pain and Functional Disability: ARandomized Controlled TrialRochenda Rydeard, PT, MSc1

Andrew Leger, PT, PhD2

Drew Smith, PhD3

Study Design: A randomized controlled trial, pretest-posttest design, with a 3-, 6-, and 12-monthfollow-up.

Objectives: To investigate the efficacy of a therapeutic exercise approach in a population withchronic low back pain (LBP).

Background: Therapeutic approaches developed from the Pilates method are becoming increas-ingly popular; however, there have been no reports on their efficacy.

Methods and Measures: Thirty-nine physically active subjects between 20 and 55 years old withchronic LBP were randomly assigned to 1 of 2 groups. The specific-exercise-training group

participated in a 4-week program consisting of training on specialized (Pilates) exercise

equipment, while the control group received the usual care, defined as consultation with aphysician and other specialists and healthcare professionals, as necessary. Treatment sessions were

designed to train the activation of specific muscles thought to stabilize the lumbar-pelvic region.

Functional disability outcomes were measured with The Roland Morris Disability Questionnaire

(RMQ/RMDQ-HK) and average pain intensity using a 101-point numerical rating scale.

Results: There was a significantly lower level of functional disability (P = .023) and average painintensity (P = .002) in the specific-exercise-training group than in the control group following the

treatment intervention period. The posttest adjusted mean in functional disability level in the

specific-exercise-training group was 2.0 (95% CI, 1.3 to 2.7) RMQ/RMDQ-HK points compared to

a posttest adjusted mean in the control group of 3.2 (95% CI, 2.5 to 4.0) RMQ/RMDQ-HK points.

The posttest adjusted mean in pain intensity in the specific-exercise-training group was 18.3 (95%

CI, 11.8 to 24.8), as compared to 33.9 (95% CI, 26.9 to 41.0) in the control group. Improved

disability scores in the specific-exercise-training group were maintained for up to 12 months

following treatment intervention.

Conclusions: The individuals in the specific-exercise-training group reported a significant decreasein LBP and disability, which was maintained over a 12-month follow-up period. Treatment with a

1 Graduate student (at time of study), School of Rehabilitation Therapy, Queens University, Kingston,Ontario, Canada.2 Educational Developer, Centre for Teaching and Learning, Queens University, Canada; AssistantProfessor (at time of study), School of Rehabilitation Therapy, Queens University, Kingston, Ontario,Canada.3 Senior Lecturer, Department of Sport and Exercise Science, The University of Auckland, Auckland, NewZealand; Assistant Professor (at time of study), Department of Rehabilitation Sciences, The Hong KongPolytechnic University, Hung Hom, Hong Kong SAR, China.The protocol for this study was approved by The Faculty of Health Science Research Ethics Board,Queens University, Canada and Hong Kong Polytechnic University Human Subjects Ethics Subcommittee,Hong Kong Special Administrative Region.Address corresondence to A. B. Leger, Centre for Teaching and Learning, Queens University, Kingston,Ontario K7L 3N6, Canada. E-mail: [email protected]

modified Pilates-based approach was more effi-

cacious than usual care in a population with

chronic, unresolved LBP. J Orthop Sports PhysTher 2006;36(7):472-484. doi:10.2519/jospt.2006.2144

Key Words: exercise rehabilitation,lumbar spine muscle recruitment,stabilization exercises

Low back pain (LBP)represents the mostcommon cause of dis-ability in persons un-der 45 years of age.1

Spinal disorders represent at least40% of the compensated disorderstreated by physiotherapists, and70% of these spinal disorders in-

volve the lumbar spine.39

The effectiveness of therapeutice xe rc is e in the tre atme nt o f

chronic LBP is currently underreview.22,28,39,43,44 General condi-tioning programs to train strengthand endurance of the spine mus-culature have been shown to re-duce pain intensity and disability28

and to be useful in the treatmentof nonspecific chronic LBP22,44

and activity-related spinal disor-ders.39 Much of the literatureexamining chronic LBP and exer-cise interventions study a popula-tion whose pain and disability

472 Journal of Orthopaedic & Sports Physical Therapy

Journal of Orthopaedic & Sports Physical TherapyOfficial Publication of the Orthopaedic and Sports Physical Therapy Sections of the American Physical Therapy Association


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manifest in deconditioning syndrome, as describedby Mayer.22 It follows that exercise-training programsdirected generally at muscle strength, endurance, andreconditioning are appropriate. However, physicaldeconditioning may not be the limiting factor torecovery for many patients seeking treatment forchronic low back disorders; it is now accepted thatmuscle dysfunction in chronic LBP may not simply bea problem of muscle strength or endurance. Instead,the problem may be one of altered neuromuscularcontrol mechanisms affecting muscular stability of thetrunk and movement efficiency.5,15,17,29 Bergmark3

classifies spinal stability as being comprised of 2(muscular) mechanisms: local mechanisms, wherebydeep, local muscles act to control movement at theintervertebral segment, and global mechanisms,

whereby muscles control movement of the spinegenerally and at multiple segments. Effective control

of both mechanisms is necessary for efficient stabiliza-tion of the spine and alterations in neuromuscularcontrol and the loss of normal patterns of spinalmotion will cause pain.26 Further, Edgerton et al5

suggest that pain and pathology result in changes inneural input to motor neuron pools affecting muscleactivation. A general reconditioning approach,through its lack of specificity, may reinforce abnormalmuscle recruitment and perpetuate compensatorystrategies that may have developed as a result ofneuromuscular adaptation over time.

Consequently, specifically designed therapeutic ex-ercise approaches that enhance spinal stability andmodulate neuromuscular control in the presence ofchronic LBP have been embraced by physiotherapists.Techniques evaluated in the literature to date addressmuscle activation directed at the intervertebral seg-ment via the cocontraction of the deep abdominalsand the paraspinals, enhancing stabilization at thelumbar spine segments.25 Recent evidence supportsthe effectiveness of such a specific-exercise approachin a chronic LBP population with a diagnosis ofspondylolysis or spondylolisthesis.25,44 OSullivan andcolleagues25 found a significant reduction in painintensity (P = .0006) and functional disability levels(P = .0001) in a group who received specific exercise

with maintenance of effect over a 30-month follow-

up. No significant changes were seen in a controlgroup receiving usual care.

The Pilates Method37 is an exercise method popu-lar for decades in dance training and the dancemedicine community. The Pilates Method is a uniqueapproach to training in mind-body awareness andcontrol of movement and posture. Specialized appa-ratus provides an opportunity to train a variety ofmovement patterns and postures. The neuromusculardemands of traditional Pilates methods can be quitehigh and therefore a modification of this method isnecessary for application to physiotherapeutic inter-

ventions. The technique used in this study was

adapted but consistent with traditional Pilates tech-niques, focusing on postural symmetry and controlledmovement. Particular emphasis, however, was placedon specific muscle activation strategies thought tostabilize the lumbar-pelvic region.

A modified Pilates approach to improve postureand control movement can thus be supported withina theoretical context of neuromuscular control andbuilds upon the concept of stability about a localspinal segment. Global stability mechanisms to con-trol the lumbar-pelvic region are then incorporatedinto this background of segmental lumbar control.This may be achieved by incorporating specific activa-tion of the gluteal muscles to stabilize the lumbar-pelvic region while performing hip extension.34,35

Stability of the trunk is thereby accomplished byusing an overlapping of stabilization strategies. Fur-ther, the use of Pilates apparatus to train stabilizationstrategies during movement may enhance the effectof a relatively more static mat exercise. This may beimportant for retention of treatment effects andtransfer to everyday movement and functional activi-ties.

The function of the hip extensors and the gluteusmaximus is thought to be central to stability andcontrol in the lumbar-pelvic region.14,18 The gluteusmaximus muscle may play an important role inlumbar-pelvic mechanics and load transfer from thelumbar spine to the pelvis and lower extremities.46

Altered recruitment of the lumbar-pelvic musculatureand dysfunction of the gluteus maximus muscle isreported in LBP conditions.4,24,47 Janda14,15 describesa characteristic pseudoparesis of the gluteusmaximus in LBP, characterized by hypotonia and adelay in activation. A concomitant imbalance in thefunctional length or recruitment of the hamstringsand/or superficial lumbar erector spinae relative tothe gluteus maximus has been associated withLBP.2,13-15,24,36 The resultant pull of muscle forcesmay impact adversely on neuromuscular control ofhip extension and the ability of the trunk to stabilizeeffectively against the demands of loading duringactivities such as walking.

Evidence supporting the effect on pain and disabil-

ity from specific exercise approaches applied tononspecific chronic LBP has not been confirmed.Similarly, no studies to date have examined theeffects of a specific exercise training approach thatemphasizes lumbar-pelvic stability and the function ofthe gluteus maximus. As well, no clinical researchactivities have been reported to date that elucidatethe efficacy of an exercise intervention based on thePilates Method in the treatment of chronic LBP.

Therefore, the objectives of this study were toinvestigate the efficacy of a specific-exercise interven-tion based on the Pilates Method and emphasizingspecific-activation strategies of the gluteus maximus

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and the effect on LBP intensity and functionaldisability in an identified population with nonspecificchronic LBP.

METHODS

Subjects

Fifty-five subjects were recruited over a 4-monthperiod through notices posted to private and publicphysicians and physiotherapists offices, noticesposted to local sports clubs and Universities, and byadvertisement in an English-language newspaper (Fig-ure 1). The subjects were recruited from a popula-tion of physically active adults between 20 and 55

years of age, living in Hong Kong, with longstanding,persistent LBP (with or without leg pain) of greaterthan 6 weeks duration or recurring LBP (with at least

2 painful incidences per year) of sufficient intensityto restrict functional activity in some manner. Physi-cally active was defined as participation in a mini-mum of three 30-minute sessions per week of activityrequiring a moderate effort in keeping with estab-lished guidelines for physical fitness.6,42 This criterionensured that findings cannot simply be attributed todisuse secondary to deconditioning and low activitylevels. Similarly, this criterion may have helped toeliminate those LBP conditions that might haveresponded to general physical conditioning exercise

without requiring more specific neuromuscular train-ing. Subsequent clinical screening was performed byan independent physiotherapist evaluator to test forevidence of neuromuscular dysfunction and fulfill-ment of the following criteria: (a) strength recordingof grade 4 or less out of 5 on manual muscle testingof the gluteus maximus14,18; (b) altered recruitmentof the gluteus maximus muscle as determined clini-cally by visual and manual inspection during a proneleg extension test.13,36,38

Prospective subjects were excluded from the studyif they were pregnant, had a past history of spinalsurgery or spinal fracture, were diagnosed with in-flammatory joint disease, systemic metabolic disorder,rheumatic disease, or chronic pain syndrome, showedevidence of overt neurological compromise or acute

inflammatory process, or had difficulty understandingwritten or spoken English. Thirty-nine subjects metthe selection criteria for inclusion in the study and 16subjects were excluded. Testing was performed at theHong Kong Polytechnic University. The clinical inter-

vention was conducted at a private physiotherapyclinic in Hong Kong, which specialized in Pilates-based interventions. All subjects signed informedconsent forms upon entry to the trial and the rightsof the subjects were protected. The Faculty of HealthScience Research Ethics Board, Queens University,Kingston, Ontario and the Hong Kong PolytechnicUniversity Human Subjects Ethics Subcommittee,

Hong Kong Special Administrative Region, grantedethics approval for the study. Subject characteristicsare reported in Table 1.

Study DesignThe study consisted of 2 parts, a pretest-posttest

control group design in part 1 (the primary study)and in part 2 (a follow-up on the exercise interven-tion group over a 1-year period). Simple randomiza-tion was performed at entry to the trial aftereligibility was determined. Randomization was admin-istered by independent office staff. Subjects randomlypulled a card from a box of concealed premarkedcards to obtain assignment to either the specific-exercise-training group (SETG) or control group(CG) without specific exercise training (Figure 1).The subjects had no preconceived expectations for

treatment because at the time of the study the Pilatesmethod was not commonly known. The subjects wereadvised that the study was designed to evaluate theeffectiveness of this specific-exercise intervention inthe treatment of LBP.

Intervention

Those in the CG group received no specific exer-cise training and continued with usual care, definedas consultation with a physician and other specialistsand healthcare professionals as necessary. They werenot restricted from seeking any other treatment ifthey so wished. Subjects were instructed to continueto do what they were previously doing, includingregular physical activity. For ethical reasons the CGhad the option to receive, free of charge, thespecific-exercise-training program 4 weeks later, aftercollection of posttreatment intervention outcomedata from the main study. During the main studyperiod, although subjects were aware they couldreceive the exercise intervention, they were notfamiliar with the technique or aware of any details of

what the treatment entailed.The SETG received a treatment protocol consisting

of training on specialized (Pilates) exercise apparatusin the clinic for three 1-hour sessions per week, and

training in a 15-minute home program performed 6days per week for 4 weeks. Treatment was provided atno charge to the subjects. The apparatus used in theclinic consisted of a floor mat and a Pilates Reformer

with standing platform and jump-board attachments(Balanced Body, Sacramento, CA). The Pilates Re-former is made of a sliding horizontal platform

within a box-like frame, upon which the subject sits,stands, kneels, or reclines. Varying resistance tomovement is provided via light springs attached tothe moving platform and through a simple pulleysystem. The subject moves against the low externalresistance offered by the springs.

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Figure 1. Subject flow during the study.


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TABLE 1. Subject characteristics and demographic data for the specific exercise-training group (SETG) and the control group (CG).

Subject Characteristics CG SETG P Value

Gender P = .77*Male 8 6

Female 13 12Age (y) 34 (8) 37 (9) P = .34

Height (cm) 171(10) 169 (8) P = .65

Mass (kg) 69 (15) 68 (14) P = .92

Durat ion of symptoms (y) Median, 9 (range, 1-20) Median, 5.5 (range, 0.5-27.0) P = .25

Nature of condition P = .58*Chronic 16 15Recurrent 5 3

Area of symptoms P = .27*Low back pain (LBP) 11 9LBP and leg pain above knee 3 6LBP and leg pain below knee 7 3

Previous physiotherapy treatment 19 16 P = .87*Included exercise therapy 15 14 P = .65*Functional disability (mean SD) 4.2 3.6 3.1 2.5 P = .14

Pain intensity score (mean SD) 30.4 17.6 23.0 17.7 P = .56

* Chi-Square test. Unpaired t test. Mann-Whitney U test.

The clinic treatment protocol was provided in anindividualized manner by 1 of 2 experienced physio-therapists trained in the treatment protocol andblinded to the results of testing. The standardized,progressive treatment protocol addressed targetedmuscle activation strategies throughout a variety ofmovement patterns involving hip extension. Thesubject was required to consciously recruit specificmusclesthe deep anterolateral abdominals (withc oactivatio n o f the pelvic f lo or and lum barmultifidus), followed by activation of the gluteusmaximus muscles. Static postures were initiallytrained (Figure 2), followed by training a variety ofmovement patterns to stress the lumbar-pelvic regionand involving hip extension (Figure 3). The training

was progressed on the Pilates Reformer (Figure 4)over the 4-week period as tolerated. Initially move-ments were practiced using weight-bearing patterns insupine, with the lumbar spine in the neutral position.Gradually more upright postures and controlledmovement of the lumbar-pelvic region out of neutralposture were incorporated. Prescribed movements

were performed slowly, smoothly, and without pain.Individualized facilitation strategies were provided bythe physiotherapist to correct technique, controlspeed, assist appropriate muscle activation, or modifythe exercise or the progression to suit the subjectsneeds. Facilitation strategies included mental and

visual imagery, manual or verbal cueing, and demon-stration.

The home treatment protocol consisted of 2 parts:(1) floor exercises to specifically activate the deepanterolateral abdominals and local stability syner-gists31 and the gluteus maximus muscle by movingthe leg in a manner similar to that utilized on the

apparatus (Figures 2 and 3) and (2) skill drills inwhich difficult tasks were broken down into move-ment components and practiced in isolation incorpo-rating correct abdominal and gluteal control.Compliance with the home exercise program wasencouraged and was self-monitored on a log sheet.The treating physiotherapist kept clinical notes docu-menting details of the treatment program and thesubjects progress.

Outcome Measure Testing

Data collection monitored both pain intensity andfunctional status and included 2 self-report question-naires administered by the research assistant, anindependent physiotherapist investigator blinded togroup assignment. In part 1 all subjects were testedon baseline measures at entry to the study (pretest-ing). Retesting of both groups was done at the end ofthe 4-week treatment intervention period (posttest-ing). In part 2, disability measures for retention oftreatment effect were collected from the SETG using

a questionnaire mailed to the subjects over a 12-month follow-up period.

Pain Intensity Outcome The NRS-101, a 101-pointnumerical rating scale, was used to measure subjec-tive pain intensity.16 The subject rated his or herperceived pain level between 0 and 100, with 0representing no pain and 100 representing pain asbad as it could be. The test protocol asked subjects to

verbally state the number that best described theaverage amount of pain they had experienced in thepast week. The number noted by the subject wasrecorded on the subjects record card and used fordata analysis.



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Figure 2. The subject was required to consciously recruit specificmuscles: the deep anterolateral abdominals (with coactivation of thepelvic floor and lumbar multifidus), followed by activation of thegluteus muscle to control a static posture.

Functional Disability Outcome Functional disability wasevaluated with the RMQ32,33 and the RMDQ-HK.11

This tool is a self-administered questionnaire listingactivities that can be compromised by LBP. The RMQ(English version)/RMDQ-HK (Chinese version vali-dated in a Hong Kong Chinese population) is aself-administered questionnaire consisting of 24 itemsto measure disability secondary to LBP. The scores

range from 0 to 24, with 0 representing no disabilityand a score of 24 indicating severe disability.

Statistical Analysis

Statistical analysis was performed using SPSS soft-ware. Results were considered statistically significant ifthe P value was less than .05

Part 1 Subject characteristics, such as height andbody mass, were compared between groups prior tothe treatment intervention using unpaired t tests.Gender distribution, nature of condition, area ofsymptoms, previous physiotherapy treatment, and theinclusion exercise therapy were compared with anonparametric statistics. Duration of symptoms(years), however, was analyzed with a nonparametrictest, considering the positively skewed nature of thedata. Outcome measures following the 4-week treat-

ment intervention period were compared betweenthe 2 groups using an analysis of covariance accord-ing to the general linear model, with group (2 levels:CG and SETG) as main factor, prestest measurementsas a covariate, and posttest measurements as depen-dent variable.

Part 2 RMQ/RMDQ-HK data were collected for theSETG immediately after and at 3, 6, and 12 monthsfollowing the treatment intervention period. Asfollow-up information was not available for someparticipants, a sensitivity analysis with 4 intention-to-treat analyses was conducted to evaluate the retentionof treatment effect. First, missing data of all random-ized subjects were handled with the last observation

carried forward (LOCF) imputation method andanalyzed with a repeated-measures ANOVA on thedifferent periods that data were collected, followed bypost hoc analyses using Fishers least significantdifference test. To verify the robustness of the conclu-sions of the analysis, 3 intention-to-treat analyses wereconducted with 3 alternative approaches. The

ANOVAs were carried out for the subjects with acomplete data set only, and then the worst-case value

was imputed to the missing data, and finally thebest-case value. Post hoc analyses were once againconducted using the Fisher least significant differencetest.

RESULTS

Subjects

Subjects were recruited over a 4-month period. Thetreatment intervention took place over a 4-weekperiod from the time of randomization. Analysisindicated no significant difference between thegroups regarding baseline characteristics (Table 1).The study sample represented a population oflongstanding LBP conditions with the median dura-tion of symptoms in the CG (n = 18) and SETG (n =


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Figure 3. Static posture training was followed by training the controlof a variety of movement patterns involving hip extension.

21) at 9 years (range, 1-20 years) and 5.5 years(range, 0.5-27 years), respectively. Twenty percent ofthe entire subject group described their LBP condi-tion to be one of a recurring nature and 80% of thesubjects described their condition to be of a chronic,persistent nature. Ninety percent of all subjects hadreceived previous physiotherapy intervention and74% of those interventions had included exercisetherapy.

All subjects in the main study completed the4-week treatment intervention according to the study

protocol and questionnaire data were collected foranalysis from all subjects in the main study. Responserate to posttreatment intervention questionnaires inpart 2 was 86% at 3 months, 57% at 6 months, and62% at 12 months (Figure 1).

Treatment Efficacy (Part 1)

After adjusting for measurements at pretest, therewas a significant reduction in average pain intensity(P = .002) and in functional disability (P = .023) inthe SETG following the treatment intervention pe-riod (Table 2). No significant interactions betweenpretreatment and group were detected for either test.The means and adjusted means and standard errorsof the mean for the SETG and CG pretreatment andposttreatment intervention period are depicted

graphically in Figures 5 and 6. The posttest adjustedmean in the SETG was 2.0 (95% CI, 1.3 to 2.7)RMQ/RMDQ-HK points compared to a posttest ad-

justed mean in the CG of 3.2 (95% CI, 2.5 to 4.0)RMQ/RMDQ-HK points. The posttest adjusted meanin pain intensity in the SETG was 18.3 (95% CI, 11.8to 24.8) NRS points, as compared to 33.9 (95% CI,26.9 to 41.0) NRS points in the control group.

Retention of Treatment Effect (Part 2)

Retention of treatment effects was examined in theSETG for RMQ/ RMDQ-HK data collected at 3, 6,

and 12 months following the completion of the mainstudy (Table 3).

The first intention-to-treat analysis, using LOCF,revealed significant improvements in RMQ/RMDQ-HK scores over the 12-month period (P.01)(Figure 7). Post hoc analysis showed a significantdifference between pretreatment and posttreatment,and pretreatment and the 3 follow-up periods. Datafor the posttreatment differed from the 3- and6-month periods, but not from the 12-month period.However, no differences were found among the 3follow-up periods. The analysis suggests that treat-ment effects were not only retained over time but

that the functional disability score decreased furtherfollowing the completion of the treatment interven-tion up until 3 months. From 3 months to 12months, the effects seem to be maintained, althoughthese results should be considered with caution,knowing the lack of significant difference betweenposttreatment results and the 12-month follow-up.

The other 3 intention-to-treat analyses supported,for the most part, the results found. Significantimprovements were found for the group of subjects

with a complete data set (P.01) and for the data setwith best-case value imputed to the missing data(P.01). Post hoc tests also showed similar results,



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Figure 4. Training progressed on the Pilates Reformer initially involving weight-bearing movements in a lumbar-pelvic neutral position. Iftolerated, more nonweight-bearing movements and control of postures out of neutral were introduced.

with the exception that the best-case method did notfind a difference between the posttreatment and the12-month period. When the worst-case value wasimputed to the missing data, the results from theanalysis did not show a difference between theperiods (P = .12).

DISCUSSION

The main finding of this study was that a programo f s pe cific e xe rc is e dir ec te d at r etrain in gneuromuscular control, provided by a physiotherapist,and based on the Pilates method was more effica-


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TABLE 2. Pretest means (SEM) and adjusted posttest means for functional disability and pain intensity for the specific-exercise-traininggroup and the control group.

Control Group (n = 18)Specific-Exercise-Training

group (n = 21)

Outcome Measures Pretreatment Posttreatment Pretreatment Posttreatment P Value*

Functional disability 4.2 (0.8) 3.2 (0.4) 3.1 (0.6) 2.0 (0.3) .023Pain intensity score 30.4 (4.2) 33.9 (3.5) 23.0 (3.9) 18.3 (3.2) .002

* Comparison of posttest scores using pretest scores as covariate.

cious in reducing pain intensity and functional dis-ability levels when compared to usual care. In thisstudy there were significant improvements in meanaverage pain intensity and in functional disabilitylevels in the SETG following treatment that were notapparent in the CG. Both groups completed thestudy and compliance was high, with 100% atten-

dance at scheduled clinic appointments. Althoughcompliance with the home protocol was not mea-sured, it was monitored on a log, and a verbal reportfrom the treating physiotherapist reported good com-pliance in general. The ability to exercise withoutpain, the opportunity to practice at home, and thequick changes in pain and carryover to functionrelative to previous chronic condition were reportedas important motivating factors for compliance.

The results of this study are in agreement with theconclusion of a systematic review of the literature45

and the findings by OSullivan et al25 and Lindgrenet al.20 These investigators found that a trainingapproach that followed the principles of segmentalstabilization and neuromuscular control was effectivein reducing pain20,25 and disability25 in a group ofindividuals with chronic LBP related specifically toradiological instability. The current study demon-strates that an exercise training approach similarlyaddressing neuromuscular control mechanisms is ef-fective in decreasing pain and improving function inan identified group with nonspecific chronic LBP

when compared to a control group. The subjects inthe OSullivan et al25 study were trained in stabiliza-tion exercises designed to enhance local muscularstability of the intervertebral segment. Although thetheoretical rationale of training muscle activation and

control was similar in both studies, the trainingapproach in the current study necessarily differedand addressed dif ferent components of neuromuscular dysfunction. The subjects in the cur-rent study did not demonstrate a primary segmentalinstability but clinically appeared to display problemsin control of the muscles thought to stabilize thelumbar-pelvis region during hip extension and load-ing.14,38,46 Therefore, in both the home and theclinic protocol, both local and global stabilizationstrategies were employed. The transversely orientedabdominal muscles, the lumbar multifidi, the dia-phragm, and the muscles of the pelvic floor have all

been shown to be important for local stabiliza-tion.7,8,10,12 Specific activation of the gluteal muscles

was emphasized in this study to assist with globalstability of the lumbar-pelvis-hip region during move-ment. The Pilates Reformer was used to train a

variety of functional movement patterns involving hipextension.

In the current study it is not known whether thetreatment effect found was due to training the localstability system or from training more general stabili-zation strategies. Similarly, it is impossible to disassoci-ate the effect of the clinic intervention from theeffects of the home intervention.

The subjects in the study reflected a chronic LBPpopulation with a mean duration of symptoms of 8.2

years. Despite chronic symptoms, this group was ableto participate in some form of physical activity at afrequency of 3 times per week. Mean initial RMQ/RMDQ-HK scores for both groups fell within thelowest strata (0-9) identified by Stratford et al,40

suggesting a relatively low level of reported disability.Despite the apparently low disability and moderateactivity levels, all subjects continued to report func-tional restrictions not resolved with previous interven-tions. It is speculated that this functional limitation

was the motivation to continue to seek treatment. Allsubjects had received treatment in the past and 90%had received previous physiotherapy treatment(s),74% of which had included exercise therapy. Most ofthe subjects had seen more than 1 medical specialistover the years and were continuing to seek treatment.There were no differences between the 2 groups inany of these characteristics. This population mayrepresent a significant subgroup of patients with

chronic LBP who seek ongoing treatment in theclinic setting and it may be argued that the needs ofthis group are not adequately met by traditionalinterventions, identifying a gap in physical medicineservice delivery.

It may be argued that a more useful indicator ofoutcome may be the clinical significance of changesin disability that are identified in a population withlow initial RMQ/RMDQ-HK scores. The minimalclinically important difference (MCID) represents thechange in function that is important to an individualpatient,4 and it is a function of the initial RMQscores. Stratford and colleagues40 have determined



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Figure 5. Average pain intensity scores for specific-exercise-traininggroup (SETG) (n = 21) and control group (CG) (n = 18) previous to(pre) and immediately following (post) the treatment interventionperiod. Values are means (pre) and adjusted means (post) andstandard error of the means. *Significant difference of post scores,using pre scores as covariate.

Figure 6. Functional disability scores for specific-exercise-traininggroup (SETG) (n = 21) and control group (CG) (n = 18) previous to(pre) and immediately following (post) the treatment interventionperiod. Values are means (pre) and adjusted means (post) andstandard error of the means. *Significant difference of post scores,using pre scores as covariate.

that a change of 1 to 2 RMQ points is reflective ofclinically important changes in subjects whose initial

RMQ scores fall within the lowest strata. These resultsmay reflect clinically important changes in functionaldisability in the group who received specific exercisetraining in contrast to the group who did not. Thislends further support that treatment with specificPilates-based exercise was more effective than usualcare in attaining clinically meaningful changes infunctional capacity in our group of subjects. Further-more, although the changes in functional disabilityare small when examining a group whose pretreat-ment and posttreatment scores fall within the loweststrata, it may also be important that no subjectsreported an increase in disability throughout thestudy period.

The subjects in this study fall under the broadclassification of nonspecific LBP, although the inclu-sion criteria were strictly controlled. Classification

into more homogenous groups of LBP diagnosis withan intervention tailored according to the needs ofthe particular group is thought likely to enhancetreatment efficacy.19 Roland and Morris32,33 suggestthat if an intervention is applied indiscriminately toall patients with LBP, it is unlikely that any majoreffect from treatment will be discerned. Due to thenatural history of LBP it was felt necessary to controlfor some of its variability and the tight inclusioncriteria attempted to facilitate homogeneity. All sub-

jects reported unresolved chronic LBP, were physi-cally active, and showed evidence on clinicaltests13,18,38 of altered performance in the musclesabout the lumbar-pelvic region, including the gluteus

maximus muscle. It was felt that subjects meeting thecriteria would be more likely to respond to thistreatment approach. Therefore it follows that a limita-tion of this study may be that results cannot beextrapolated with confidence to chronic LBP condi-tions outside of the selection criteria for this study,and especially individuals with acute or more dis-abling LBP. The high percentage of subjects receivingrecent care from a health professional, the extent ofpast physical treatments, and the prior level ofexposure to physiotherapy and exercise interventionssuggest a response to the intervention itself as op-posed to a placebo effect. Additionally, given the

chronic nature of the subjects conditions, it is notlikely that the results in the SETG are due to thepassage of time.

Similarly, the results in the SETG cannot simply beexplained by the introduction of physical training, asonly physically active subjects were selected for thestudy. Subjects in both groups continued with generalphysical training or advice as prescribed by theindependent evaluator and their attending practi-tioner throughout the duration of the study.

Finally, all of the subjects in the CG were instructedthat they would have the opportunity to receivetreatment after a 4-week period.

0

10

20

30

40

50

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AveragePainIntensity(0to100NRSpoin

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(0=nopain,100=severepain)

CGSETG

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1

2

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8

9

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FunctionalDisability(0

to24RMQ/RMDQ-HK

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TABLE 3. Retention of treatment effects for functional disability for the specific-exercise-training group previous to (prettreatment), im-mediately following (posttreatment), 3, 6, and 12 months after the treatment intervention for the data collected and with the last obser-vation carried forward intention-to-treat analysis. Values are in means (SEM).

Pretreatment Posttreatment 3 Months 6 Months 12 Months

Data collected 3.1 (0.6) 1.7 (0.4) 0.9 (0.4) 0. 4 (0.2) 0.9 (0.6)n 21 21 18 12 13

Last observation carried forward 3.1 (0.6) 1.7 (0.4) 1.0 (0.4) 1.0 (0.4) 1.1 (0.4)n 21 21 21 21 21

Figure 7. Functional disability scores for specific-exercise-training group (SETG) previous to (pre) and immediately following (post) thetreatment intervention and at 3-, 6-, and 12-month follow-up, using the last observation carried forward intention-to-treat analysis. Valuesare means and standard error of the means (n = 21).

To measure for retention of treatment effect,disability measures were collected from the SETG by

questionnaire over a 12-month period followingcompletion of the treatment. Due to the noncompli-ance of some subjects, the data were analyzed using asensitivity analysis contrasting 4 intention-to-treatanalyses. First the missing data were replaced by theLOCF value. Analysis of these data indicated lowermean functional disability levels were relatively wellmaintained over the 12-month follow-up period. Thebiggest changes occurred from the pretreatment tothe 3-month follow-up. The disability levels in thetreatment group were negligible by the 6-monthperiod and any further changes may not have been ofclinical importance.

To evaluate the robustness of these results, theanalysis was conducted again but with 3 different

methods of handling the missing data. Results werethe same with the sample of subjects with a completedata set as well as with the best-case value as imputingmethod. Results did not show a significant difference,however, when using the worst-case value. Consider-ing this last analysis and the substantial loss of data,the conclusions drawn from the results should beconsidered with caution.

The lower response rates of 57% for the 6-monthand 62% for the 12-month follow-ups may confoundthe strength of any findings beyond the 3-monthfollow-up, depending on the reason for dropout fromthis part of the study. Three subjects were lost



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following posttesting and 1 subject was lost at the12-month follow-up. Some of the subjects who didnot respond at 6 months did at 12 months and vice

versa. An analysis of the group of subjects who didnot respond to either or both of the 6- and 12-monthfollow-ups were shown to have responded similarly tothe program on all outcomes compared to the group

who provided all follow-up data. These findingswould suggest that factors other than a difference instatus or treatment response acted to influence par-ticipation throughout the follow-up period in thisgroup.

Ability and concomitant disability are relative toindividual expectations of function. Also important

were unsolicited comments on the questionnairesreturned from subjects whose RMQ/RMDQ-HKscores throughout the follow-up period were 0 out of24. These subjects described a progressive ability to

return to activities that had been previously stoppedsecondary to low back problems that could not bereflected in the RMQ/RMDQ-HK scores. The RMQ/RMDQ-HK may not be sensitive enough to pick upthese changes in ability despite the significance fornormal function in this population. An alternative,more sensitive measure for this population that hassimilar measurement properties to the RMQ/RMDQ-HK is not currently available. Such a measuremay be useful in demonstrating change in thissubgroup of patients with chronic LBP who continueto seek care in physiotherapy.

Clinical Implications

This group of patients may represent individualsseen in physiotherapy clinics and who seek ongoingtreatment from healthcare practitioners after subse-quent return to normal daily activities despitechronic LBP. The return to normal activities is often

with some restrictions and limitations and accompa-nied with longstanding or recurrent pain. It is thislack of full recovery and ongoing pain that appearsto prompt this clientele to seek ongoing treatment. It

would appear that a treatm ent to re-educateneuromuscular control strategies with a structured

approach in the clinic environment and comple-mented with incorporation into a subject-specificfunctional task is beneficial in the restoration offunctional ability levels acceptable to the patient. Thisspecialized exercise approach can be adjunctive to, ormay follow other treatment at some point in thecontinuum of rehabilitation interventions.

In summary, an exercise approach that targetsselective muscle recruitment and neuromuscular re-training of stabilization strategies may have a signifi-cant effect on pain and disability in a population ofactive subjects with chronic LBP, with long-lastingeffects. A modification of the Pilates method may

provide a useful and cost effective treatment modalityin the management of such conditions and meritsfurther study.

CONCLUSIONSThe results of the study support the hypothesis that

an exercise therapy approach based on the Pilatesmethod and directed at neuromuscular controlmechanisms was efficacious in the treatment of agroup of individuals with nonspecific chronic LBP. A4-week treatment intervention was more efficaciousthan usual care in reducing average pain intensityand functional disability levels, changes were main-tained over a 12-month period.

ACKNOWLEDGMENTSThe authors would like to thank Professor Lo Sing

Kai, Deakin University and Karine Charpentier,Queens University, for statistical advice.

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