Feasibility of an Eight-Week Dance-BasedExercise Program and Its Effects onLocomotor Ability of Persons withFunctional Class III Rheumatoid Arthritis

Helene Moffet, Luc Noreau, Eric Parent, and Melanie Drolet

Objectives. The main objectives of this experi-mental case series were to evaluate the feasibility ofa modified dance-based exercise program with lowground impacts in persons with rheumatoid arthritis(RA) functional class III and to describe its effects onlocomotor ability. The relationship between 3 loco-motor tests and their responsiveness also were ad-dressed.

Methods. Ten female subjects participated in an8-week exercise program. Locomotor ability wasmeasured before and after the program using the50-foot test of walking time, the 6-minute test ofwalking distance, and the locomotion biomechani-cal analysis.

Results. All subjects showed a high compliance(92.5% presence at sessions) over the 8 weeks ofexercise without any aggravation in disease status.They were able to train efficiently at moderate inten-

sity up to 25 minutes. Significant improvementswere found in locomotor ability, with a higher re-sponsiveness measured by the locomotion biome-chanical analysis, followed by the 6-minute gait testand the 50-foot gait test. Inconsistent relationshipsbetween tests suggested that different locomotorabilities are required during tests.

Conclusion. These results support the feasibilityof a modified dance-based exercise program for per-sons with severe RA. With high levels of responsive-ness, the detailed biomechanical analysis and the6-minute gait test are recommended for the assess-ment of locomotor ability.

Key words. Rheumatoid arthritis; Exercise; Loco-motor performance.

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflamma-tory disease characterized by systemic and jointmanifestations (1,2) that have deleterious conse-quences on the individual’s functional indepen-dence. Most persons with RA experience functionaldisability related to their joint limitation, muscleweakness, and low level of cardiorespiratory fitness(3,4). Until the end of the 1970s, conventional RAtreatment included rest combined with pharmaco-therapy and physiotherapy centered on the reduc-tion of specific motor disabilities. Rest did not bringas many benefits as expected, and it was found onlymarginally superior to activity in a large group of

Supported by the Rehabilitation Research Consortium of East-ern Quebec. Mr. Parent and Ms Drolet were the recipients of asummer studentship from the Medical Research Council of Can-ada and the Fonds de la Recherche en Sante du Quebec, respec-tively.

Helene Moffet, PhD, PT, Luc Noreau, PhD, EdPhys, Eric Parent,BSc, PT, Melanie Drolet, MSc, PT, Quebec Rehabilitation Instituteand Department of Rehabilitation, Faculty of Medicine, LavalUniversity, Quebec City, Quebec, Canada.

Address correspondence to Helene Moffet, PhD, PT, Depart-ment of Rehabilitation, Faculty of Medicine, Laval University,Quebec (Qc), G1K 7P4 Canada.

Submitted for publication December 17, 1999; accepted in re-vised form January 13, 2000.

© 2000 by the American College of Rheumatology.

100 0893-7524/00/$5.00

patients (5). Consequently, a growing interest beganto emerge in global intervention directed at func-tional recovery, including cardiorespiratory training,muscle strengthening, and joint mobility.

Several supervised training programs on bicycleergometers have been assessed in populations witharthritis. They led to improvements in performingdaily activities related to better locomotor and car-diorespiratory functions without inducing adverseeffects on the individuals’ joints and general health(6–10). Others have evaluated the feasibility andeffectiveness of aerobic programs including weight-bearing exercises such as tai-chi chuan exercises(11), walking, and aquatic jogging (12–14). In somecases, the gains obtained following the training weremaintained for at least 6 months following cessationof the program (6,7,12).

More recently, Perlman et al (15) analyzed, in per-sons with RA (functional class I–III), the effect of a16-week dance-based aerobic exercise program(EDUCIZE) combined with educational support.They reported improved general condition (reduc-tion of disease activity) and gait performance and areduction of the arthritis’ impact on the participants’quality of life with no harmful effects on joint con-dition. Members of our research team (16) evaluateda similar program (EDUCIZE modified) in personswith RA of functional classes I and II and describedits specific benefits in cardiorespiratory fitness andother parameters. A 13% improvement in aerobicpower (VO2 max) associated with positive changes ofthe psychological and mood states with no harmfuleffects on the systemic and joint condition levelswas found after 12 weeks of training.

In light of these previous studies, it seems thattraining programs have beneficial effects on the gen-eral condition and more specifically on the cardio-respiratory and locomotor functions of persons withRA. The effect of such a program, however, has notbeen investigated in persons with RA who have amore severe level of disability (functional class III).In addition, when evaluations of locomotor perfor-mance have been performed, they have been under-taken in an incomplete manner since only spatio-temporal parameters were studied (4,6–9,11–22).Other parameters ensuing from locomotion biome-chanical analysis (kinetic and kinematic parameters)are, however, essential to the comprehension of thecauses of change (23). Consequently, we designed aresearch study to: 1) evaluate the feasibility of the8-week modified dance-based exercise program withlow ground impacts in a group of RA patients withsevere levels of disability, and 2) describe its effectson cardiorespiratory and locomotor function, health

status, functional independence, and psychologicalstate.

The changes induced by the program in cardiore-spiratory function, general health status, functionalindependence, and psychological state were dis-cussed in a previous report (24). The results showedimprovements in cardiorespiratory fitness (VO2 max)between 10% and 20% in 4 out of the 10 personswith RA. Positive changes in depression, anxiety,fatigue, and tension were also observed after the8-week exercise program (24). In the present report,results related to detailed locomotor analyses, in-cluding performance in the 50-foot test of walkingtime, the 6-minute test of walking distance, and thelocomotion biomechanical analysis, are reported.The relationship between these 3 commonly usedassessment procedures and their responsiveness alsoare addressed.

PATIENTS AND METHODS

Subjects. A sample of 10 volunteer subjects wererecruited from the Quebec City metropolitan areawith the following criteria for inclusion: 1) a con-firmed diagnosis of RA functional class III (25), 2)not being in a flare-up period, 3) free of unstablecardiopulmonary disease and neurodegenerativedisease, 4) no lower limb surgery during the last 6months, and 5) ability to ambulate over short dis-tances with or without walking aids. According tothe revised criteria for global functional status in RA(25), functional class III includes persons able toperform usual self-care activities but who are limitedin vocational (work, school, homemaking) and avo-cational (recreational and/or leisure) activities. The3 other classes are as follows: class I 5 completelyable to perform usual activities of daily living (self-care, vocational, and avocational); class II 5 able toperform usual self-care and vocational activities, butlimited in avocational activities; and class IV 5 lim-ited in ability to perform usual self-care, vocational,and avocational activities. All participants signed aconsent form after a detailed explanation of theproject’s purposes and procedures as approved bythe ethics committee of the Quebec RehabilitationInstitute. The study did not include a control groupof persons with RA given the exploratory nature ofthe study (feasibility study) and the small numbersof persons with RA functional class III in the Quebecregion.

Experimental design. The experimental designconsisted of an “initial evaluation” (pre) followed by

Arthritis Care and Research Locomotor Changes After Dance-Based Exercise 101

the intervention and a “final evaluation” (post). Bothevaluations included two testing sessions for a du-ration of approximately two hours. They took placewithin the week that preceded the beginning of thetraining program and that immediately followed theprogram. The same test sequence was implementedduring the initial and final evaluations at the sametime of day. The dance-based exercise program wascarried out over 8 weeks, in a format of 1-hour train-ing sessions twice a week. Clinical data were col-lected before and after each training session to verifythe participants’ joint condition.

Evaluations. The first evaluation session wasmade up of the following stages: reading and signingthe consent form, a medical evaluation to verify thesubjects’ admissibility and to evaluate their generalcondition (associated conditions, contra-indicationto exercise, and medication), and joint condition(pain and swelling). The Ritchie articular index wasused to evaluate pain intensity (0 to 3 scale; 0 5 nopain and 3 5 extreme pain) of the 26 joints mostoften affected by RA (26). The swelling index, whichalso used a 3-level scale, quantified the swelling ofthe same target joints except for some where swell-ing cannot be assessed in a clinical evaluation (hips,cervical column, midtarsal, and subtalar joints).These indexes have demonstrated a very high in-trarater reliability (27). The participants subse-quently performed a graded exercise test on a tread-mill (24). During this test, a variation of the speedand/or slope at each minute allowed a constant riseof the physiologic demand (0.7 mets.min-1) until ex-haustion or appearance of exercise intolerance. Thismodification, compared with a regular protocol (stepof 2 or 3 minutes, and workload increase of about 2mets), was necessary to avoid the possibility that thetest be stopped because of muscle fatigue rather thancardiorespiratory exhaustion. All procedures re-spected the rules established by the American Col-lege of Sports Medicine for maximal graded exercisetesting (28). Then, after a rest period of at least 10minutes, the 50-foot test of walking time was per-formed. At the end of this session, blood samplingwas done to determine the hemoglobin rate and sed-imentation speed, which are indicators of diseasestate.

The second session of evaluation began with thelocomotion biomechanical analysis. The partici-pants filled out questionnaires assessing the physicalcomponent and the psychological state (24). The50-foot test of walking time was subsequently done asecond time. Finally, the distance covered over 6 min-

utes was measured (the 6-minute test of walking dis-tance). Over the course of the two evaluation sessions,rest periods were granted to those who wanted them.

Description of the locomotor tests. The 50-foottest of walking time. This test consisted of recordingthe time for an individual to cover a distance of 50feet by walking as quickly as possible. The test wascarried out in a long corridor. All participants re-ceived the same standardized instructions from anexperienced evaluator. After having given the depar-ture signal, the evaluator started the chronometer atthe first sign of the subject’s movement and stoppedwhen she crossed the finish line. No encouragementwas given to the subject during the test. Visual su-pervision, or closer if necessary, was offered to allsubjects. A high level of reliability for this test wasdescribed beforehand in the literature (27,29,30).This test has been used in many studies with personswith RA (4,8,11,12,15–17).

The 6-minute test of walking distance. This testconsisted of measuring the distance covered by aperson walking at natural cadence for a period of 6minutes. It was done in a long corridor marked every5 meters over a distance of 50 meters. Subjectswalked back and forth over this distance as manytimes as possible for a period of 6 minutes. Beforethe test, they all received the same standardizedinstructions. For the duration of the test, the evalu-ator remained in a location that allowed visual sur-veillance. At the end of the test, the evaluator notedprecisely the position of the person on the path.Psychometric properties of this test have been de-scribed (31,32). It has been used in populations withcardiac (32,33), respiratory (31,34), and arthriticproblems (20–22).

Locomotion biomechanical analysis. Spatiotem-poral, kinematic, and kinetic variables of walking atnatural cadence were measured on a 10-meter walk-way in a locomotion laboratory. Hip, knee, and anklemovements were measured using a 2-dimensionalvideo system (Neogenix Technologies, Sainte-Foy,Canada) and 14 circular reflective markers (4 cm indiameter) installed bilaterally on the following bodylandmarks: humeral head, greater trochanter and lat-eral epicondyle of the femur, mid-leg (mid distancebetween lateral epicondyle of the femur and lateralmalleolus), lateral malleolus, fifth metatarsophalan-geal joint, and heel (posterolateral part). Ground re-action forces were recorded with an AMTI forceplatform (Advanced Mechanical Technology Inc.,Newton, MA) placed at the halfway point of thewalkway. Spatiotemporal parameters were obtainedfrom footswitches taped under both shoes. Foot-

102 Moffet et al Vol. 13, No. 2, April 2000

switch signals were transmitted to the computer by atelemetric system. All signals were recorded simul-taneously (sampling frequency of 60 Hz) with thehelp of software developed for the acquisition andanalysis of these data.

Before the test, the subjects walked a short dis-tance to familiarize themselves with the evaluationprocedure. Then, they were asked to walk at theirnatural cadence along the 10-meter walkway. Theyperformed as many trials as necessary in order toobtain two valid gait cycles for each side of the body(two cycles containing adequate foot contacts on theforce platform). Rest periods were granted to thosewho wanted them.

Training program and clinical followup. Thedance-based exercise program was developed andled by a physical fitness instructor in collaborationwith an occupational and a physical therapist. Eachtraining session included 4 phases, all taking placeto musical arrangements: warm-up, aerobic exercise,recovery, and cool-down. The warm-up began in asitting position (5 minutes), then continued in astanding position (2 minutes) for an average durationof 7 minutes. Isolated and combined movements ofthe joints of the upper and lower extremities in pain-free ranges of motion were performed. In addition,stretching exercises for the ankle plantar flexors,knee extensors, and elbow extensors were included.The second phase, the aerobic period, lasted 10 min-utes for the first 2 weeks of the program. A fewminutes were added each week to reach a total of 25minutes by the end of the program. The dance-basedexercise period was made up of slow movementscreating a rhythmic pattern that involved all joints.Ground high impacts, abrupt movements, circum-duction, and cervical movements were avoided. Theexercises included in this phase were numerous.Examples are walking movements (forward, back-ward, and lateral) with simultaneous elbow andshoulder movements (flexion-extension, abduction-adduction). Subsequently, over the course of recov-ery, subjects continued moving around, walkingslowly and gently moving their upper arms in cardi-nal planes, for a period of 3 minutes. At the end ofeach session, the participants experimented withdifferent relaxation techniques for a period of 4 to 5minutes.

To control exercise intensity, the heart rate (HR) ofall the participants was monitored 4 times at eachmeeting (resting and following the warm-up, aero-bics, and cool-down). For the first 3 weeks of theprogram, the participants had to reach a target HRfrequency corresponding to 50% of their maximal

HR during aerobic exercise. However, according totheir performance in the effort test, some of themwere restrained to an intensity effort correspondingto 40% of maximal HR. Throughout the program,when predetermined frequency targets were reachedand maintained, a new objective was set in such away that, over the term of the program, a large pro-portion of the participants trained for a target fre-quency equivalent to 60% or 70% of their maximalHR. For the length of the program, the participantswho showed particularities during the exercise teston the treadmill (high blood pressure, elevated HR)were followed with Sport Tester PE 300 cardio-tachymeters (Polar Electro Inc., Washington, NY).

To document tolerance to the exercise and theimmediate effect of the training program, measuresdescribed as “clinical followups” were done regu-larly. Before and after each training session, the par-ticipants rated the intensity of their knee and shoul-der pain with the help of visual analog scales. Also,in order to keep following the evolution of the par-ticipants’ joint condition, active knee joint andshoulder amplitudes were measured once a week.These two target joints were chosen to documentclinical changes in the upper and lower limbs be-cause they were the most frequently impaired joints(shoulders and knees: 90% and 60% of the partici-pants, respectively) at the beginning of the trainingprogram.

Data and statistical analyses. The time perfor-mances of the 50-foot (mean of the two trials, inseconds) and the distance performance of the6-minute (in centimeters) gait tests were convertedto gait speed (centimeters per second) to facilitateintertest comparisons. Considering the short dura-tion of the 50-foot gait test and the variability inperformance we observed, two trials were carriedout, each on a separate day, to verify the stability ofthe performance. Because no intertrial differencewas found (Wilcoxon matched-pairs signed-ranktest; P . 0.05), the mean performance (n 5 2 trials)was used for further analysis. Biomechanical datacollected in the locomotion laboratory were ob-served cycle by cycle. Two representative gait cyclesof the locomotor performance for each individualwere chosen on both sides (right and left half of thebody). All subsequent analyses were done with theaverage of the two cycles recorded from the right halfof the body, since both sides presented no notabledifference. This choice was done in an arbitrary fash-ion. For each subject and both evaluations, spatio-temporal, kinematic, and kinetic variables were,

Arthritis Care and Research Locomotor Changes After Dance-Based Exercise 103

thereafter, calculated. The most relevant variablesare listed in Tables 1 and 2.

The selected kinematic variables were chosen torepresent the global mobility of the lower limb joints(total range of motion used during walking) and theprecise joint behavior in critical periods of walking

(initial contact, maximum amplitudes in specificallydemanding subphases of the activity). The kineticvariables retained were those indicative of the exten-sor lower limb mechanical demand during thestance phase of walking. Area under the hip andknee extensor moment of force bursts and the ankle

Table 1. Comparison of spatiotemporal variables between pre- and posttest*

Tests and variables Controls†

Persons with rheumatoid arthritis

Pretest Posttest Change‡ P value§

50-foot gait test¶

Speed (cm/sec) NA 131.9 6 31.3 143.0 6 22.1 9.5 6 15.9 0.110

6-minute gait test¶

Speed (cm/sec) 125.0 6 15.9 111.4 6 18.2 126.0 6 11.1 10.6 6 10.2 0.017#

Laboratory gait test¶

Speed (cm/sec) 126.5 6 15.9 90.7 6 21.3 105.7 6 18.5 14.7 6 8.0 0.008#Cycle duration (sec) 1.10 6 0.1 1.24 6 0.1 1.15 6 0.1 20.1 6 0.1 0.008#Cadence (step/min) 110.3 6 10.9 97.1 6 7.3 104.8 6 7.5 7.7 6 3.9 0.008#Stride length (cm) 136.2 6 9.8 110.4 6 21.8 119.9 6 20.7 9.0 6 8.7 0.021#

* Values represent mean 6 SD. NA 5 not available.† All normative spatiotemporal values were obtained from a group of 18 healthy persons except for the 6-minute test mean value that came from a differentgroup of 21 healthy persons.‡ Changes between pre- and posttest values.§ P value from Wilcoxon signed-rank test comparing mean values between pre- and posttest.¶ 9 persons with rheumatoid arthritis completed the 50-foot and laboratory gait tests, and 8 completed the 6-minute gait test.# Significant change.

Table 2. Comparison of kinematic and kinetic variables between pre- and posttest*

VariablesControls(n 5 18)

Persons with rheumatoid arthritis (n 5 9)

Pretest Posttest Change† P value‡

Kinematic (degrees)

Hip

Total range 37.0 6 3.5 34.2 6 4.6 36.4 6 4.8 2.3 6 2.5 0.038§Flexion at initial contact 20.0 6 4.6 15.3 6 4.3 18.2 6 2.3 2.9 6 3.6 0.051Maximum flexion during swing 21.2 6 4.9 18.2 6 6.5 21.2 6 4.5 2.9 6 2.8 0.021§

Knee

Total range 62.6 6 4.4 59.1 6 10.0 60.3 6 7.8 1.2 6 4.8 0.678Flexion at initial contact 0.3 6 3.9 20.3 6 3.6 0.7 6 3.4 1.0 6 2.4 0.260Maximum flexion during stance 16.8 6 5.3 10.2 6 3.6 14.3 6 3.6 4.0 6 2.8 0.011§Maximum flexion during swing 61.7 6 3.6 57.2 6 7.2 59.8 6 7.6 2.6 6 4.4 0.110

Ankle

Total range 26.2 6 4.0 26.2 6 4.0 25.4 6 4.4 20.8 6 2.7 0.594Flexion at initial contact 2.7 6 3.5 22.4 6 4.0 22.4 6 2.2 0.0 6 3.3 0.859Maximum dorsiflexion 16.4 6 2.7 15.0 6 3.2 15.1 6 3.3 0.1 6 2.2 0.859Maximum plantar flexion 29.5 6 5.2 29.9 6 6.8 29.2 6 4.7 0.6 6 4.0 0.767

Kinetic (N.m.s/kg)

Support moment area 32.3 6 6.4 25.3 6 7.5 31.3 6 3.6 6.0 6 6.6 0.051

* Values represent mean 6 SD.† Change between pre- and posttest values.‡ P value from Wilcoxon signed-rank test comparing mean values between pre- and posttest.§ Significant change.

104 Moffet et al Vol. 13, No. 2, April 2000

plantar flexor moment of force were first analyzed toobtain an indication of the extensor work at eachjoint. Then, the global lower limb extensor work wascalculated using the area under the support momentprofile. Changes in these kinematic and kinetic vari-ables help explain the changes observed in the spa-tiotemporal variables (23,35,36). The maximum kneeflexion during stance combined with the magnitudeof the knee extensor moment of force were used asindicators of the shock absorption capacity of theknee after initial contact.

Results of the biomechanical variables were com-pared with reference values obtained from a healthygroup of 18 subjects (mean age 60 6 8 years; 9women and 9 men). The 6-minute test performanceof the persons with RA was, otherwise, comparedwith a normative value that comes from anothergroup of 21 healthy subjects (mean age 67 6 8 years;10 women and 11 men). These reference values werecollected in the framework of earlier projects in thesame laboratory and with the same procedure(37,38). No reference value was available for the50-foot gait test.

The central tendency and dispersion measures(mean 6 standard deviation), and changes over thecourse of the training program (posttest minus pre-test performance) were calculated for all continuousvariables. Nonparametric statistics were used be-cause of the small number of subjects and large datavariability. The Wilcoxon matched-pairs signed-rank test was used for the pre- and posttraining com-parisons. To compare the 3 locomotor tests at thesame period (pre- or posttraining), Friedman’s ana-lysis of variance tests were done. Correlative analy-ses were done with the Spearman test between thewalking speed values measured by the 3 locomotortests before and after the training and between themagnitude of change in these 3 tests. For all statisti-cal analyses, the significance level was set at a 50.05. All analyses were done with the software Sys-tat (Systat Inc., Evanston, IL) on Macintosh and thesoftware GBSTAT (Dynamic Microsystems Inc., Sil-ver Spring, MD) on IBM. Finally, the responsivenessof each locomotor test was determined with the stan-dardized response mean, which is the ratio of themean change to the standard deviation of change (39).

RESULTS

Subject characteristics. Ten women (mean age54 6 10 years; duration of disease 14 6 9 years) wererecruited for this study. Nine of them were consid-

ered as part of RA functional class III and one class II(25). Joint deformities (skeletal malalignment) weremore prevalent in distal joints than in proximaljoints (feet and ankles 78%; knees 44%; hips 22%;hands and wrists 100%; elbows 44%; shoulders22%). The majority of the participants were takinganti-inflammatory drugs or remittive agents. Overthe course of the training program, only 3 partici-pants had to change their medication plan. One be-gan to use prednisone while another withdrew itfrom her medication regimen. The last individualbegan salazopirine for a 2-week duration, afterwhich the medication was interrupted because of theappearance of undesirable side effects (bleeding,nausea, vomiting). Finally, no change was observedin the occurrence of associated conditions over thecourse of the study followup.

Feasibility. Compliance. All participants com-pleted 8 weeks of the dance-based exercise program.The average rate of participation was very high(92.5% sessions), varying from 13 to 16 sessions outof a possible 16. In all participants except one (no. 4),the intensity of training was progressively increasedas expected. In the first (training sessions 1 to 5), thesecond (sessions 6 to 11), and the third (sessions 12to 16) periods, the percentage of the mean reserve HRreached was, respectively, 42 6 10%, 56 6 5%, and63 6 5%. Participant no. 4 had to restrain her train-ing to a mean intensity of 44% HR reserve because ofeffort hypertension.

Although 9 of the participants were evaluated be-forehand at the training for each of the tests, one ofthe participants was not able to do the 6-minute testof walking distance (pre and post) due to her level offatigue after the effort test. Also, this same partici-pant did not redo the effort test on the treadmill atthe end of the program since her hemoglobin rate (86g/l) was judged too low to do it within safe limits.This is possibly attributable to secondary effects(bleeding, nausea, vomiting) from the salazopirinetreatment that she began during the followup. Fi-nally, at the end of the program, another participantwas not able to do the effort test on the treadmill andthe locomotor tests due to the rupture of a Baker cystin the right lower limb. This rupture occurred duringthe weekend when the participant had to walk morethan usual for activities outside the program.

Disease status. Examination of the various param-eters of disease status indicated no aggravation to thegeneral or joint condition (Tables 3). Conversely, asignificant decrease in joint swelling was observedafter the training program.

Arthritis Care and Research Locomotor Changes After Dance-Based Exercise 105

Clinical followup measurements. No significantchange was observed in joint pain intensity and am-plitude of motion over the course of the first and lasttraining sessions (Table 4).

Locomotor performance. Pre–post training changes.Pre- and posttraining spatiotemporal variables forthe 3 locomotor tests are summarized in Table 1. Gaitspeed measured in the laboratory and during the6-minute test of walking distance increased signifi-cantly following the training program, whereas nosignificant change was observed in the 50-foot test ofwalking time. From the locomotion biomechanicalanalysis, a significant reduction in the duration ofthe gait cycle also was observed in conjunction withan increase in stride length. Observed changes in thepre- to posttraining period varied from 7% to 18% incomparison with baseline values. Most of thechanges in the laboratory gait test performance werenot sufficient to reach normal values, except for cy-cle duration. On the other hand, performance in the6-minute gait test was similar to healthy controls atthe posttest.

Significant kinematic changes were observed formaximum knee flexion during the stance phase and

for all hip variables except the flexion amplitude atinitial foot contact, which borders on the significantthreshold (P 5 0.051; Table 2). All these variablesincreased in value, drawing closer to the referencevalues, after the training program. No significantchange was observed in the ankle. The area underthe moment of support profile (kinetic variable) wasincreased toward reference value (P 5 0.051). Themagnitude of pre- and posttraining changes variedslightly, from 1 to 4 degrees, for the different kine-matic variables, while the support moment area in-creased in a large proportion (34%) in comparisonwith baseline value.

Intertest comparisons before and after the trainingprogram. Mean speed values measured by each ofthe 3 locomotor tests were significantly differentfrom each other before the training program (P 50.0008) and after it (P 5 0.0008). On the other hand,no significant difference was observed between themagnitude of the speed changes in these 3 tests overthe course of the training program (P 5 0.33).

Relationships between locomotor tests. For eachof the 3 tests, the speed measured at the initial eval-uation was positively correlated to the speed mea-sured at the final evaluation (r 5 0.71 to 0.90), aswell as negatively correlated to the changes occur-ring over the course of the exercise period (r 5 -0.76to -0.87) (Table 5). This indicates that individualswith greater gait speeds at the initial evaluation alsoshowed greater speeds at the final evaluation, buthad smaller changes over the course of the training.

Furthermore, only the speed measured in the 50-foot test was significantly correlated with those mea-sured in the two other tests at the initial evaluation.However, following the exercise program, the speedsin the 3 tests were not significantly correlated. Fi-nally, the magnitude of change measured by the50-foot test was significantly correlated with thatmeasured by the 6-minute test (r 5 0.74). No other

Table 3. Comparison of disease status between pre- andposttest*

Variables Pretest Posttest P value†

Ritchie index (range 0–78) 22.0 6 8.5 21.0 6 5.1 0.48Swelling index(range 0–57) 18.8 6 5.8 14.3 6 3.5 0.05‡

Hemoglobin rate (g/l) 123.9 6 15.2 121.9 6 20.2 0.48Erythrocyte sedimentation(mm/h) 26.9 6 12.4 29.7 6 19.8 0.72

* Values represent mean 6 SD (n 5 10).† P value for Wilcoxon signed-rank test comparing mean between pre- andposttest.‡ Significant change.

Table 4. Comparison of joint pain and mobility between the first two weeks and the last two weeks of the trainingprogram*

VariablesFirst 2 weeks oftraining program

Last 2 weeks oftraining program P value†

Shoulder flexion amplitude (degrees) 122 6 21/128 6 26 133 6 35/134 6 33 0.20/0.24Knee flexion amplitude (degrees) 131 6 6/128 6 11 129 6 5/127 6 10 0.15/0.44Knee extension amplitude (degrees) 21 6 4/21 6 4 21 6 3/21 6 3 0.45/0.62Intensity of shoulder pain (mm)‡ 22 6 19/23 6 26 23 6 16/19 6 18 0.96/0.58Intensity of knee pain (mm)‡ 23 6 24/22 6 29 22 6 18/16 6 18 0.80/0.24

* Values represent mean 6 SD (n 5 10) of the right and left sides (right/left).† P value for Wilcoxon signed-rank test.‡ Intensity of pain measured with visual analog scales (0 mm 5 no pain; 100 mm 5 excruciating pain).

106 Moffet et al Vol. 13, No. 2, April 2000

significant correlation was observed in the magni-tude of changes.

Responsiveness of the locomotor tests. The stan-dardized response mean indexes for the variable“speed” measured by the 50-foot, the 6-minute, andthe laboratory gait tests were, respectively, 0.60,1.04, and 1.84. The 50-foot test ranked as the leastresponsive, followed by the 6-minute test and thelaboratory gait test.

DISCUSSION

Results of this study supported, for the first time,the feasibility of a dance-based exercise programwith low impacts and controlled movements in asample of persons with RA functional class III. In-deed, our subjects were able to sustain an exerciseprogram at moderate intensity (about 55% of HRreserves) for a sufficient duration (25 minutes) toallow training benefits according to criteria estab-lished by the American College of Sports Medicine(40). Also, all participated with excellent attendance(92.5% presence) over the 8 weeks of exercise with-out showing any aggravation of their joint conditionor of disease status. Such a program was likely fea-sible in persons with RA with severe deformities inthe upper and lower limbs and significant functionallimitations because it was adapted to individual ca-pacities. A dance-based exercise program, withoutground high impacts, appears to be a safe method oftraining for people with arthritis, even with an ad-

vanced stage of the disease. In addition, the satisfac-tion expressed by the participants suggests that atraining program constitutes a pleasant, stimulating,and beneficial activity for persons with RA. Thisresult corroborates previous studies carried out in per-sons with arthritis and with less severe disabilities(functional classes I and II) (4,6–8,10–13,15,18,19,41).

The findings of this study also confirm the hypoth-esis that an exercise program significantly improveslocomotor abilities. For 2 of the 3 locomotor testsused, the 6-minute and the laboratory gait tests, im-provements in gait speed were observed. The extentof the gait speed improvement measured in the6-minute gait test (11.7%) corresponds to the onenoted earlier in persons with RA, and persons withosteoarthritis or cardiac or respiratory problems (20–22). In conjunction with results of a previous study(33), our results demonstrate that the 6-minute testpresents a sufficient responsiveness to observechanges linked to the effects of training programs aswell as laboratory gait tests.

The absence of significant changes in the 50-footgait test is somewhat surprising. This test has fre-quently been used as an outcome measure in drugtrials because it makes up part of the recommendedmeasures by organizations such as the Food andDrug Administration and the Traditional OutcomeWorkshop to document the effects of therapy onpersons with RA (27). However, less than 50% ofstudies measuring anti-inflammatory effects have ob-served significant changes in the locomotor perfor-mance with the help of this 50-foot gait test (42). One

Table 5. Intra- and intertest relationships for speed values and changes over the course of the training program*

Pretest Posttest Change†

50F 6M LAB 50F 6M LAB 50F 6M LAB

Pretest

50F 1 – – 0.90‡ – – 20.87‡ – –6M 0.95‡ 1 – – 0.71‡ – – 20.86‡ –LAB 0.65‡ 0.37 1 – – 0.85‡ – – 20.76‡

Posttest

50F – – – 1 – – – – –6M – – – 0.52 1 – – – –LAB – – – 0.17 0.26 1 – – –

Change

50F – – – – – – 1 – –6M – – – – – – 0.74‡ 1 –LAB – – – – – – 0.40 0.31 1

* Spearman correlation coefficient; intratest relationships are shown over the diagonal and intertest relationships under the diagonal. 50F 5 50-foot gait test;6M 5 6-minute gait test; LAB 5 laboratory gait test.† Change between pre- and posttest values.‡ Significant correlation (P , 0.05).

Arthritis Care and Research Locomotor Changes After Dance-Based Exercise 107

may question whether the test is responsive enoughto detect clinically important change, as suggestedby Anderson and colleagues (43). Consequently, inthe present study, it is possible that a test with aduration of 12 seconds is minimally responsive.Some of the variability in performance may be ex-plained by the inclusion of the acceleration phase atthe beginning of the test. As well, it can be difficultto understand and reproduce an effort when askingthe subjects to walk at a maximal speed. Conse-quently, one can understand that when following aprogram so short (8 weeks, 16 sessions) for a group ofsubjects with a large variability of impairments, theexpected size change is small (a few seconds) andvery variable. This makes it even more difficult todemonstrate significant changes, especially in a smallgroup of subjects. Results of this study confirm thepoor responsiveness of the 50-foot gait test and, there-fore, do not support its use as an outcome measure.

Generally, the laboratory gait speed of the subjectsin this study corresponds to that of other groupsevaluated in previous studies. Measured speed def-icits, as compared with healthy subjects of the sameage and sex, are within the limits described in theliterature (reduction of 23% to 78%) (36,44–49) atthe pretest (28%), while after training, they areslightly lower (16%). These differences have beenattributed to a reduction in cadence and step length(36,44–50). Thus, significant increases in the ca-dence and stride length, and reduction of the cycleduration are some positive effects of the exerciseprogram.

The improvement in kinetic and kinematic vari-ables after the training program also was confirmedby comparing the locomotor performance of the per-sons with RA with normative data. This analysisallowed us to identify significant improvements intotal range of motion at the hip, which was mainlydue to increased hip flexion, initial knee flexionduring the stance phase, and kinetic variables suchas the area under the support moment profile. Afterthe training period, the residual impairments inmovements and moment of forces can both be attrib-uted to the disease and to a slower gait. It is wellknown that a reduction in gait speed can result in anamplitude reduction of movements and forces whilewalking (23,36). Results of the present study must beinterpreted by taking into account these two factorswhose effects cannot be dissociated and that are, infact, interrelated.

At the kinetic level, an increase in area under thesupport moment represents an improvement in thesum of the extensor moment of force to the 3 lowerlimb joints during the stance phase. This change can

be explained by increases in the hip and knee exten-sor moments of force at the beginning of the gaitcycle (0 to 30% of the cycle). In the second part ofthe stance phase (30% to 60% of the cycle), changesin the support moment of force are smaller and arelargely attributable to a greater moment of force gen-erated by the ankle plantar flexor muscles. Thus,changes to the 3 joints contributed to increasing themagnitude of the support moment. This change ap-pears clinically important. It suggests that a weight-bearing exercise program allows improvement in theglobal function of lower limbs by contributing to theimprovement of the action of extensor antigravitymuscles in the 3 joints. Interestingly, the larger kneeextensor moment occurring concomitantly with anincreased amplitude in knee flexion in early stancesuggests that the extensor muscles had a better ca-pacity, after the training program, to control shockabsorption (23,51). This may be due to several fac-tors including improved muscle recruitment, in-creased strength, or decreased knee pain.

Although measures of the locomotor ability usedin this study represent a range of measures usedmostly in the framework of research focusing on RA,no study has analyzed the relationships existing be-tween the various locomotor tests. It is important toknow if these tests measure the same aspects of thelocomotor abilities and if they demonstrate the samemagnitude of change over time. At first, our hypoth-esis was that all 3 tests would be correlated, assum-ing that they for the most part require the sameabilities. Results of our study do not completelysupport this hypothesis. Indeed, a significant corre-lation between tests was only found in the initialevaluation between the 50-foot gait test and the twoothers. None of these correlations were found overthe term of the program, and the speeds of the6-minute gait test and the locomotion biomechanicalanalysis had never been correlated. Finally, the mag-nitude of changes observed by the 50-foot and6-minute gait tests are the only ones to have beencorrelated. Some elements can be considered in theintertest correlative analysis interpretation. Instruc-tions given to the subjects about gait speeds weredifferent from one test to the other, as were the pathlength and evaluation conditions. It is likely thatthese differences were sufficient to highlight differ-ent aspects of locomotor ability.

Gait speeds measured at the initial evaluation foreach of the locomotor tests were positively corre-lated with those obtained at the final evaluation, andnegatively with the percentages of change for thesame test. This means that data obtained at the initialevaluation can predict the final evaluation and

108 Moffet et al Vol. 13, No. 2, April 2000

change results. Thus, for each test, a subject havingobtained a high result before the training programhas a strong chance of obtaining a result among thehighest at the final evaluation. This same subjectwill, however, obtain a weak change in comparisonwith a subject obtaining weak results at the initialevaluation. This result is very interesting since itdemonstrates, on the one hand, the importance ofthe pre-exercise state as compared with the post-exercise one. On the other hand, it confirms that thecloser an individual is to his/her “optimal” perfor-mance, the greater is the likelihood that the changesobserved following the exercise will be small.

For the interpretation of results, some limitationshave to be considered. First, because the populationof subjects with RA functional class III in the Quebecregion is limited, it was not possible to proceed witha rigorous random sampling and to constitute a con-trol group. Subjects were included in the study on avoluntary basis, which suggests that the participantswere motivated by and had from the beginning of thestudy a positive attitude toward physical activityand the evaluated program. The small number ofparticipants and the significant variability in theircases, despite the fact that 9 of the 10 participantswere evaluated functional class III, have to be con-sidered in the interpretation of results.

The great tolerance to the training program and thepositive effects observed could also have been attrib-uted to other factors. The change of one subject’smedication is one of the most obvious. In this study,only one addition of prednisone would have beenable to decrease the swelling or to control the pain ofa participant. The summer season, social contacts,efforts provided to bring them to the rehabilitationcenter, as well as an attention bias (Hawthorne ef-fect) are all potential factors that could have inducedpositive changes in the state of the participants.Thus, in this study, we can only estimate the signif-icance of the intervention effects. To draw validconclusions about the effectiveness of a new inter-vention, a randomized study with a control groupwould have been necessary. Also, it would havebeen of interest to analyze the impact of lower limbjoint deformities on gait performance and responseto training. Unfortunately, no quantitative data onseverity of the deformities were gathered, renderingimpossible such an analysis. Future work may ad-dress this relevant question.

In conclusion, the feasibility of a dance-based ex-ercise program was supported by the results. Ab-sence of aggravation to the systemic and joint state isan argument favoring the practice of weight-bearingactivities by severely affected persons with RA.

Analysis of the changes that took place over thecourse of the program suggests a positive trainingeffect on locomotor ability as evaluated by the6-minute gait test and the laboratory analysis (kine-matic, kinetic, and spatiotemporal variables). Futurestudies including a larger number of subjects arenecessary in order to verify the effectiveness of sucha program. Furthermore, it would be interesting toinvestigate long-term effects of the program and itsimpact on behavioral changes regarding an activelifestyle and on benefits in everyday life activities.Finally, in the evaluation of locomotor ability, adetailed kinetic and kinematic variable analysis andthe 6-minute gait test appeared to be very useful.They were found to be responsive methods of mea-suring gait speed and are therefore recommended forthe framework of future studies. These tests should bepreferred to the much less responsive 50-foot gait test.

The authors thank Renee Fleury, Huguette Martineau, and Lu-cille Roy for their contribution to the dance-based exercise pro-gram. We are also grateful to Mireille Belzile, Renee Larouche,Danny McKinnon, and Gilles Pare for their collaboration in theevaluation sessions.

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