doi: 10.1111/joim.12481 Physical exercise as a treatment for adult and juvenile myositis H. Alexanderson 1,2 From the 1 Department of Neurobiology, Care Science and Society, Division of Physiotherapy, Karolinska Institutet, SE-14183, Huddinge; and 2 Physiotherapy Clinic, Karolinska University Hospital, Karolinska University Hospital, SE-17176, Stockholm, Sweden Abstract. Alexanderson H (Karolinska Institutet, Huddinge, Stockholm; and Karolinska University Hospital, Solna, Stockholm, Sweden). Physical exercise as a treatment for adult and juvenile myositis (Review). J Intern Med 2016; doi: 10.1111/ joim.12481. There is growing evidence to support the safety and efficacy of exercise in patients with adult and juvenile idiopathic inflammatory myopathies. Five randomized controlled trials including adult patients with polymyositis and dermatomyositis (DM) and additional open studies have demon- strated reduced impairment and activity limita- tion as well as improved quality of life. In addition, recent studies have shown reduced disease activity assessed by consensus disease activity measures and reduced expression of genes regulating inflammation and fibrosis. Furthermore, exercise could improve muscle aerobic capacity as shown by increased mito- chondrial enzyme activity. These data suggest that intensive aerobic exercise and resistance training could reduce disease activity and inflam- mation and improve muscle metabolism. Encour- aging results have been reported from available open studies including patients with inclusion body myositis (IBM) and juvenile DM, indicating reduced impairment, activity limitation and improved quality of life also in these patients. Larger studies are needed to increase under- standing of the effects of exercise in patients with active, recent-onset polymyositis and DM as well as in patients with IBM and juvenile DM. Keywords: aerobic exercise, disease activity, impairment, inflammation, inflammatory myopa- thies, resistance training. Introduction The idiopathic inflammatory myopathies (IIM) are a heterogeneous group of rare diseases that primarily affect skeletal muscles. In adults, IIMs are divided into polymyositis (PM), dermatomyosi- tis (DM) and inclusion body myositis (IBM) [1], while children are mostly affected by juvenile dermatomyositis (JDM) although some are diag- nosed with overlap juvenile idiopathic inflamma- tory myopathy [2]. The common feature of all patients with IIMs is impaired muscle function, however each subgroup presents with character- istic muscle pathology and clinical symptoms such as interstitial lung disease, fatigue and dysphagia. Patients with IBM often have a history of frequent falls [1]. Standard medical treatment for patients with PM, DM or JDM consists of oral corticos- teroids in combination with immunosuppressive treatment, although the role of biological agents is growing [3]. The World Health Organization has published the International Classification of Functioning Disabil- ity and Health (ICF) as a unified nomenclature and framework to describe health and health-related conditions as well as the impact of a health-related condition on the affected individual [4] (Figure S1). In this review, exercise effects will be described based on the ICF. Herein, structure relates to the structure of all organs in the human body, for example skeletal muscle, whereas body function relates only to the function of muscles. The term impairment will be used to describe pathological processes and reduced function of skeletal muscles. Impairment can often lead to reduced ability to perform daily activities of choice (activity limitation) and to participate in society (participation restric- tion). The ICF also comprises personal and external factors. Personal factors relate to an individual’s thoughts and beliefs or, for example, level of motivation. Environmental factors relate to family and friends as well as the living and working ª 2016 The Association for the Publication of the Journal of Internal Medicine 1 Review
Transcript
doi: 10.1111/joim.12481
Physical exercise as a treatment for adult and juvenilemyositisH. Alexanderson1,2
From the 1Department of Neurobiology, Care Science and Society, Division of Physiotherapy, Karolinska Institutet, SE-14183, Huddinge; and2Physiotherapy Clinic, Karolinska University Hospital, Karolinska University Hospital, SE-17176, Stockholm, Sweden
Abstract. Alexanderson H (Karolinska Institutet,Huddinge, Stockholm; and Karolinska UniversityHospital, Solna, Stockholm, Sweden). Physicalexercise as a treatment for adult and juvenilemyositis (Review). J Intern Med 2016; doi: 10.1111/joim.12481.
There is growing evidence to support the safetyand efficacy of exercise in patients with adult andjuvenile idiopathic inflammatory myopathies. Fiverandomized controlled trials including adultpatients with polymyositis and dermatomyositis(DM) and additional open studies have demon-strated reduced impairment and activity limita-tion as well as improved quality of life. Inaddition, recent studies have shown reduceddisease activity assessed by consensus diseaseactivity measures and reduced expression ofgenes regulating inflammation and fibrosis.
Furthermore, exercise could improve muscleaerobic capacity as shown by increased mito-chondrial enzyme activity. These data suggestthat intensive aerobic exercise and resistancetraining could reduce disease activity and inflam-mation and improve muscle metabolism. Encour-aging results have been reported from availableopen studies including patients with inclusionbody myositis (IBM) and juvenile DM, indicatingreduced impairment, activity limitation andimproved quality of life also in these patients.Larger studies are needed to increase under-standing of the effects of exercise in patients withactive, recent-onset polymyositis and DM as wellas in patients with IBM and juvenile DM.
The idiopathic inflammatory myopathies (IIM) are aheterogeneous group of rare diseases thatprimarily affect skeletal muscles. In adults, IIMsare divided into polymyositis (PM), dermatomyosi-tis (DM) and inclusion body myositis (IBM) [1],while children are mostly affected by juveniledermatomyositis (JDM) although some are diag-nosed with overlap juvenile idiopathic inflamma-tory myopathy [2]. The common feature of allpatients with IIMs is impaired muscle function,however each subgroup presents with character-istic muscle pathology and clinical symptoms suchas interstitial lung disease, fatigue and dysphagia.Patients with IBM often have a history of frequentfalls [1]. Standard medical treatment for patientswith PM, DM or JDM consists of oral corticos-teroids in combination with immunosuppressivetreatment, although the role of biological agents isgrowing [3].
The World Health Organization has published theInternational Classification of Functioning Disabil-ity and Health (ICF) as a unified nomenclature andframework to describe health and health-relatedconditions as well as the impact of a health-relatedcondition on the affected individual [4] (Figure S1).In this review, exercise effects will be describedbased on the ICF. Herein, structure relates to thestructure of all organs in the human body, forexample skeletal muscle, whereas body functionrelates only to the function of muscles. The termimpairment will be used to describe pathologicalprocesses and reduced function of skeletalmuscles.Impairment can often lead to reduced ability toperform daily activities of choice (activity limitation)and to participate in society (participation restric-tion). The ICF also comprises personal and externalfactors. Personal factors relate to an individual’sthoughts and beliefs or, for example, level ofmotivation. Environmental factors relate to familyand friends as well as the living and working
ª 2016 The Association for the Publication of the Journal of Internal Medicine 1
environment [4]. Quality of life is a multifacetedconcept that is covered by ICF domains to a limitedextent.
A large body of evidence supports the notion thatexercise is a safe and beneficial treatment forrheumatoid arthritis (i.e. another inflammatoryrheumatic disease) [5]. A Cochrane review in2013 of five randomized controlled trials (RCTs) ofexercise in muscle disease, including one studywith patients with PM or DM, demonstrated thatthe evidence for positive effects of exercise isinsufficient due to the small number of trialsincluded and their risk of bias [6]. However, sincethen the results of three additional RCTs includingadult patients with PM or DM have been published;these studies will be further discussed below [7–9].Habers and Takken concluded that although mostexercise studies are small and often without con-trol groups, they all suggest that exercise is safeand probably effective for improving muscleimpairment in all subsets of myositis patients[10]. In addition, exercise has emerged as animportant part of the treatment for patients withIIMs [9, 10]. During the last 15 years, intensiveresearch activity has resulted in the accumulationof evidence to support the benefit of exercise inpatients with both established and newlydiagnosed inflammatory active disease.
The aim of this review was to outline the effects ofexercise with regard to structure (disease activity,inflammation, metabolic milieu and muscle struc-ture) as well as impairment, activity limitation,participation restriction and quality of life inpatients with adult and juvenile IIMs, accordingto the ICF.
Exercise studies in patients with IIMs
Since the two-first case reports on the effects ofexercise in patients with myositis were published in1993, a total of 32studies evaluating exercise effectsondifferent aspects of healthhavebeenpublished inadults and children with IIMs; in all these studiesoutcome variables were considered according to theICF. A majority of studies included patients withadult PM and DM (n = 22) [7–9, 11–29], while a fewfocused on IBM (n = 6) [30–35] and JDM (n = 3) [36–38]. A small number of studies have also evaluatedthe feasibility of a single exercise test or exercisebout inpatientswithJDM[39–42]. The vastmajorityof studies have evaluated exercise in patients withnoninflammatory active established disease [7, 8,
11, 13–15,17–23, 25, 27–38],whereaspatientswithrecent-onset, inflammatory active disease wereincluded in only six studies [9, 12, 16, 18, 24, 26].All studies have investigated exercise durations of4–12 weeks except one in which exercise effects upto 6 months were studied [14]. Two studies haveincluded an open extension follow-up of between 1and 2 years [7, 9]. All studies evaluating exercisedurations >3 weeks included creatine phosphoki-nase (CK) levels as a proxy measure of diseaseactivity, all demonstrating unchanged or reducedlevels of CK following exercise. Sixteen studies alsoinvestigated the effects of exercise on diseaseactivity and muscle inflammation, metabolism andcharacteristics [7–9, 15, 16, 20–23, 25, 28, 30–32,35, 42] (Table 1).
Exercise programmes
A variety of exercise programmes have been eval-uated in patients with myositis, including resis-tance training (ranging from easy to intensive), acombination of resistance training and aerobicexercise, and exclusively aerobic exercise (Table 2).Home exercise alone or in combination with exer-cise in a hospital setting has been used in severalstudies and some have used supervised hospital-based exercise. Below, some of the exercise pro-grammes, all of which were well-tolerated, arepresented more in detail; they are referred to hereinwith programme numbers (P1–10). All exerciseprogrammes are summarized in Table 2, with thedegree of tolerability shown in Table 3.
Exercise programmes evaluated for adult patients with recent-onsetor refractory disease
One resistive home exercise programme performed5 days a week for 12 weeks (P1) is the onlyprogramme that has been extensively evaluatedfor safety analysing CK levels, magnetic resonanceimaging and inflammatory infiltrates in musclebiopsy in patients with recent-onset, active PM andDM [9, 16] (Figure S2). The absolute loads were notregistered, but patients performed about 10–15repetitions of each exercise. In an RCT [9], theprogramme was combined with outdoor aerobicwalking for 20 min, 5 days a week, at 50–70% ofestimated maximal heart rate (i.e. 220 – age).
Mattar et al. [26] were the first to evaluate exercisein refractory PM and DM using an in-hospitalresistance training and aerobic exerciseprogramme that was well-defined with regard to
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
2 ª 2016 The Association for the Publication of the Journal of Internal Medicine
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
12 ª 2016 The Association for the Publication of the Journal of Internal Medicine
Journal of Internal Medicine
Table3
Summary
ofexerciseprogra
mmes,thediagnosis
forwhichtheywere
evaluated,andtheir
tolera
bility
Exerciseprogra
mme
Diagnosis
Tolera
bility
Homeexercise,resistancetrainingand
aerobic
walkingat50–7
0%
ofestimated
maxim
alheart
rate,5daysaweekfor
12weeks(P1)[9]
Recent-onsetPM
andDM
Well-tolera
tedbyallparticipants.Theprogra
mme
neededto
bedividedbetw
eenmorn
ingandaftern
oon
sessionsduringth
efirstweeksofexercise,dueto
muscle
weaknessandfatigue,fortw
opatients
Resistancetraining(8–1
2VRM)andhigh-
intensityaerobic
exercise(P2)[26]
Refractory
PM
andDM
Well-tolera
tedbyallparticipants
Resistancetrainingat10VRM,3daysa
week,for12weeks(P3)[20]
EstablishedPM
andDM
Onepatientwitharthritisin
fingerandwristjoints
did
notquitereachgoalintensityforupperextremitytasks
Resistancetrainingat30%
of1VRM
during
vascularocclusion,tw
iceaweekfor
12weeks(P4)[25]
EstablishedPM
andDM
Well-tolera
ted
Homeexercise,resistancetraining,tw
icea
dayfor16weeks(P5)[33]
IBM
Well-tolera
tedbyallparticipants
Resistancetrainingat3–1
5VRM,
3daysweek
�1for12weeks(P6)[30]
IBM
Well-tolera
tedbyallparticipants
Aerobic
exerciseat70%
ofVO
2maxand
resistancetrainingat30–4
0%
ofVRM,
3daysweek
�1for12weeks(P7)[7]
EstablishedPM
andDM
Well-tolera
tedbyallparticipants
Home-b
asedhandexercise,3daysweek
�1
for12weeks(P8)[27]
EstablishedPM
andDM
Well-tolera
tedbyallparticipants
Resistancetrainingat8–1
2VRM
and
aerobic
exerciseat70%
ofVO
2peakfor
12weeks(P9)[37]
EstablishedJDM
Well-tolera
tedbyallparticipants
Home-b
asedaerobic
exerciseat65%
of
VO
2max,every
oth
erdayfor12weeks
(P10)[38]
EstablishedJDM
Well-tolera
tedbyallparticipants
PM,polymyositis;DM,derm
atomyositis;IB
M,inclusionbodymyositis;JDM,juvenilederm
atomyositis;VRM,voluntary
repetitionmaxim
um;VO
2max,
maxim
aloxygenuptake;VO
2peak,peakoxygenuptake.P1–1
0,specificexerciseprogra
msdescribedin
this
paper.
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
ª 2016 The Association for the Publication of the Journal of Internal Medicine 13
Journal of Internal Medicine
load and intensity. Patients exercised twice a weekfor 12 weeks (P2). Following a 5-min warm up,strength training was performed for 40 min at anintensity of 8–12 repetition maximum [(RM) i.e. theweight that can be lifted a maximum of 8–12 times)in three sets with a 1-min rest between sets. Bothupper and lower limbs were exercised, using sta-tionary training equipment, including horizontalleg presses, vertical bench presses, latissimusdorsi pull-downs, leg extensions, seated rowing,squats and abdominal crunches. Then patientsperformed high-intensity aerobic treadmill walkingfor 40 min, followed by stretching.
Exercise programmes used in patients with established, low diseaseactivity
An intensive resistance training programme wasemployed in patients with established, low-diseaseactivity PM and DM (P3) and consisted of a 10-minwarm-up on a stationary bike or a treadmill at 50%of individually estimated maximal heart rate (220 –age) followed by 45 min of resistance training at 10voluntary repetition maximum (VRM) in three setsseparated by a 90-s rest (Figure S3) [20]. Patientsexercised three times a week on nonconsecutivedays for 7 weeks and new sets of 10 VRM weretested every other week and loads were adaptedaccording to progress. Loads were initiated atabout 50% of individual 10 VRM and slowlyincreased during the first 3 weeks of exercise.
In one very recent study, a supervised submaximaltwice weekly exercise programme during blood flowrestriction for 12 weeks was evaluated in 15patients with established PM or DM (P4) [25]. Anair cuff was placed in the inguinal fold of boththighs and blood flow was restricted by 50% whileperforming leg-presses and knee extensions at 30%of 1 RM for 15 repetitions in five sets separated by a1-min rest. Exercise was introduced at lowerintensity with four sets at 20% of 1 RM duringthe first week and four sets at 30% of 1 RM duringthe following 4 weeks. New sets at 1 RM wereassessed every 4th week and exercise loads wereadjusted accordingly. This programme was welltolerated. The same research group used a similarprotocol in an earlier case study of a 65-year-oldman with IBM [35] in whom this exercise protocolalso seemed to be well tolerated.
Another home exercise programme was evaluatedin patients with IBM (P5) [33]. The programmeconsisted of whole-body rising from sitting to stand-
ing, biceps and deltoid curls, wrist flexor exercises,seated rowing, heel and toe lifts, stretching of thecalf muscles, seated dynamic knee-extensor exer-cise and isometric thigh-adductor contractions. Theprogramme was performed twice from the begin-ning, but participants were told not to exercise onany given day if experiencing fatigue or pain fromthe previous days during the first 2 weeks. Follow-ing this, participants were instructed to exercisetwice daily for the remaining 14 weeks. One of thefirst exercise studies in IBM evaluated a resistancetraining programme at loads between 3 and 15VRMin a small group of patients (P6) [30].
One RCT evaluated an aerobic exercise programmein adult patients with PM or DM including station-ary cycling at 70% of maximal oxygen uptake(VO2max) for 30 min, in combination with quadri-ceps endurance training at 30–40 VRM, performedon three nonconsecutive days a week for 12 weeks(P7) [7]. Patients initiated the exercise at about 50%of VO2max and increased intensity during the first2 weeks. Patients also performed endurance resis-tance training in the deltoids and trunk muscles atabout 30 VRM.
The first hand-exercise programme to be evaluatedin patients with PM and DM comprised exercisesfor pinch gripping, thumb opposition, fingerabduction and adduction as well as finger flexion,extension and opposition. Exercise resistance wasadapted individually with putties using standard-ized doughs (P8). During the study, the resistanceas well as the number of repetitions could beincreased (up to 30 repetitions). Patients consid-ered that the exercise programme was too long andsuggested omitting the finger abduction andadduction exercises and performing only 10–20repetitions 2–4 days a week [27]. Further evalua-tion of this programme is needed.
Exercise programmes in JDM
Two well-defined exercise programmes have beenevaluated in two small open studies in patientswith JDM. The first programme (P9) included awarm-up of treadmill walking for 5 min followed by20 min of resistance training at 8–12 VRM in threesets combined with aerobic treadmill exercise at70% of peak oxygen consumption (VO2peak) for30 min and finally stretching. The exercise wasinitiated with two sets of 15–20 VRM [37]. In thesecond study, an aerobic home exerciseprogramme was evaluated with stationary cycling
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
14 ª 2016 The Association for the Publication of the Journal of Internal Medicine
Journal of Internal Medicine
at 65% of VO2max every other day for 12 weeks(P10) [38]. Pulse rate data were collected through-out the study.
Effects of exercise in adults and children with IIM
Exercise effects on body structure: inflammation, disease activity andmuscle metabolism
The results of all published exercise studies havedemonstrated that exercise is safe in terms oftolerance and feasibility as well as inflammationand disease activity in adults and children withactive, recent-onset or refractory disease and inthose with established disease with low diseaseactivity (Table 1).
Many of the earlier studies used only assessmentsof serum CK levels as a proxy for disease activityand inflammation before and after exercise. How-ever, the introduction of the six-item core set forassessment of disease activity proposed by IMACS[43], as a tool to evaluate the effects of exercise onclinical disease activity, has led to a more clinicallyrelevant assessment of disease activity in patientswith IIMs. Criteria in this core set for minimalclinical improvement were defined as improvementby ≥20% in three of the six measures with worsen-ing by >25% in no more than two measures [notincluding the manual muscle test (MMT)] [44]. Asignificantly larger number of participants in theexercise group, seven of 11 patients in the exercisegroup who performed an intensive aerobic andmuscle endurance programme (P7) for 12 weekswere responders with reduced disease activityaccording to the IMACS criteria, compared to nopatients in the control group [7]. Two patientsresponded with reduced disease activity accordingto these criteria after 7 weeks of intensive resis-tance training (P3), and disease activity assessedby the myositis intention to treat index wasreduced in the entire group after 7 weeks of exer-cise compared to baseline [20]. After these twoexercise programmes (P3 and P7) as well as an easyto moderate 12-week home exercise programme(P1), analysis of CD3+ T cell infiltrates indicated nosigns of increased inflammation compared to acontrol group with established [8] and active dis-ease [9, 16]. Furthermore, levels of inflammatoryinfiltrates were unchanged following exercise inpatients with IBM [30, 31].
Physicians’ and patients’ global assessments ofdisease activity were significantly reduced after12 weeks of resistance training during vascular
occlusion (P4) compared to baseline in patientswith established PM and DM [25]. The intensiveexercise programme tested in three patients withrefractory PM and DM (P2) was well-tolerated by allthree patients and one showed a 33% reduction inCK levels after 12 weeks compared to baseline [26].These findings of reduced disease activity andinflammation are supported by an analysis of geneexpression using microarray analysis in repeatmuscle biopsies. A large number of genes regulat-ing inflammation and fibrosis were downregulatedafter 7 weeks of intensive resistance training (P3)[23], supporting the hypothesis that intensiveexercise could be used as an anti-inflammatorytreatment; however, these changes also need to beevaluated at the protein level. One study in JDMpatients demonstrated reduced disease activitymeasured by the Disease Activity 28 score afterexercise compared to baseline [37].
Intracellular matrix lactate levels were evaluatedby microdialysis in patients and healthy controlsubjects matched for age, gender and physicalactivity levels. The same experimental procedurewas used in patients with PM or DM at baselineand after 12 weeks of aerobic exercise and endur-ance resistance training in an RCT including anexercise group and a control group (P7) [8]. Themicrodialysis membrane was inserted in the vastuslateralis muscle and samples were collected beforeand after a stationary cycling session at 70% ofVO2max until exhaustion. There was no differencein lactate levels between healthy subjects andpatients, although cycling time until exhaustionwas significantly shorter in patients. After12 weeks, the exercise group demonstrated analmost two-fold increase in cycling time untilexhaustion with significantly lower lactate levelscompared to baseline, while there were no changesin the control group. In addition, analysis ofmuscle biopsies showed increased mitochondrialenzyme activity (citrate synthase and b-hydroxya-cayl-CoA dehydrogenase) [8]. In biopsies from asmaller subset of patients, analysis revealed anincreased number of capillaries at 12 weeks in theexercise group compared to baseline [8]. In anotherstudy, lactate levels were evaluated in blood before,during and after a submaximal treadmill walkingsession [32]. Twenty patients with established PMor DM and 15 healthy control subjects wereincluded. It was found that patients had signifi-cantly higher lactate levels and reduced walkingtime compared to the control subjects. Fourpatients started a 12-week aerobic exercise
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
ª 2016 The Association for the Publication of the Journal of Internal Medicine 15
Journal of Internal Medicine
programme at an intensity of 70% of VO2max.Results indicated significantly lower lactate levelscompared to baseline [32]. These data suggest thatpatients with established PM and DM respond toexercise with improved muscle aerobic capacityand capillarization. Phosphocreatine nucleosidetriphosphate (PCr NTP) and inorganic phosphatelevels were assessed by magnetic resonancespectroscopy after 3 and 5 months of creatinesupplements in combination with home exercise(P1) in an RCT [22]. PCr NTP levels were increasedsignificantly in the creatine supplement groupcompared to the control group [22].
A significant increase in cross-sectional area ofthe thigh muscles was recorded after resistancetraining during vascular occlusion (P4) in patientswith established PM or DM [25]. Furthermore, acase study indicated a 4.7% increased cross-sectional area in a man with IBM after a similarexercise regimen as well as increased mRNAexpression of mechanogrowth factor associatedwith muscle hypertrophy [35]. Arnardottis et al.[31] analysed muscle biopsies from seven patientswith IBM following a 12-week home exerciseprogramme and reported no change in capillarydiameter, but a significant decrease in capillarydensity; the authors speculated that this could bedue to a trend towards increased cross-sectionalarea. Habers et al. [42] studied the change inbalance between oxygen delivery and oxygenconsumption as well as blood volume usingnear-infrared spectroscopy in the vastus medialisand lateralis in children with JDM or juvenileidiopathic arthritis (JIA) and in healthy controlsubjects before and after an incremental all-outcycle ergometer test [42]. Children with JDM hadsignificantly reduced blood volume in the vastusmedialis compared to control subjects, but notcompared to children with JIA, while there was nodifference in the oxygen delivery/consumptionbalance between groups [42]. The authors con-cluded that these results could indicate thatchildren with JDM had impaired blood volumethat increased during moderate and strenuousexercise compared to healthy subjects, and thattreatment for JDM should focus on improvingoxygenation. However, these results need to beconfirmed using other imaging techniques. Agroup of adult patients with established PM andDM were found to have a reduced number oftype-1 oxygen-dependent muscle fibres comparedto healthy control subjects. Easy-to-moderatehome exercise (P1) for 12 weeks resulted in a
significant increase in the proportion of type Ifibres [21].
Based on these results it seems that resistive andaerobic exercise is not only safe but also canreduce disease activity and inflammation inpatients with myositis and that exercise couldrestore the damaged metabolic milieu in skeletalmuscle.
Effects of exercise on body functions: muscle strength and endurance,aerobic capacity, fatigue and pain
All studies conducted in patients with adult PMand DM as well as JDM have indicated reducedmuscle impairment whereas the results of studiesin IBM patients have been inconclusive (Table 2).In adults with PM and DM, aerobic/enduranceexercise had positive effects not only on muscleendurance but also on muscle strength. Wiesingeret al. [13] reported improved aerobic capacity andisometric peak torque following a 1-h exerciseprogramme of stationary cycling and step-up exer-cises in a group of seven patients compared to thecontrol group. The authors of a more recent RCTcame to the same conclusion, reporting improvedaerobic capacity and muscle endurance after30 min of intensive stationary cycling and quadri-ceps endurance training (P7) as well as improvedquadriceps strength assessed by five VRM com-pared to a nonexercising control group. It alsoseems that low-intensity resistance training duringvascular occlusion (P4) could improve musclestrength in adults with PM/DM and IBM [25, 35].
Intensive resistance training at 10 VRM in threesets (P3) resulted in marked improvements inmuscle strength in a small group of patients withestablished PM and DM, with some improvementsin muscle endurance assessed by the FunctionalIndex-2 [20].
The feasibility of a home hand-exercise programme(P8) was recently evaluated [27]. At the group level,three-jaw pinch grip improved significantly in theleft hand after 12 weeks whereas all othermeasures of strength and activity limitations wereunchanged. Several patients demonstrated aclinically relevant improvement in grip strengthlimitations defined as >15% improvementaccording to the IMACS criteria [45].
A few studies have investigated the effects of exer-cise on impairments in patients with recent-onset
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
16 ª 2016 The Association for the Publication of the Journal of Internal Medicine
Journal of Internal Medicine
or refractory adult PM and DM [9, 12, 16, 18, 26].In the only RCT, 10 patients were randomlyassigned to a resistive home exercise programme(P1) and nine patients to a range of motionprogramme about 4 weeks after diagnosis andintroduction of high-dose corticosteroids andimmunosuppression [9]. After 12 weeks there wereno significant differences in muscle endurance oraerobic capacity between the exercise and controlgroups, implying that early easy-to-moderateintensity exercise does not add any extra value toimprove function in the short-term. After the12 weeks of resistive home exercise, the exercisegroup was encouraged to start gym training twice aweek for the rest of the study duration of 2 years.The results from this programme further supportedthe safety of exercise in inflammatory, active,recent-onset myositis, but conclusions could notbe drawn about the effectiveness of frequent homeexercise. A case study including three patients withrefractory active PM and DM demonstrated thesafety of intensive resistance and aerobic training(P2). Clinically relevant improvements (>20% com-pared to baseline) in both muscle strength andaerobic capacity were observed [26].
Encouraging results were reported from an openstudy including seven patients with IBM perform-ing a resistive home exercise programme twicedaily [33]. After 16 weeks of home exercise (P5) asignificant improvement was observed in all mus-cle groups, including the knee extensors and fingerflexors, assessed by a handheld myometer. Thepatients also improved in terms of time required towalk 30 m and to climb a flight of stairs. The sameresearch group also investigated aerobic exerciseat 80% of maximal heart rate 3 days a week for12 weeks in combination with the home exerciseprogramme (P5) performed once a day for 4 days aweek. Aerobic capacity improved significantly, butmuscle strength and other functional measuresremained unchanged [34]. The results of an earlyopen exercise study indicated improved musclestrength following intensive resistance training (P6)assessed by three VRM of between 25% and 120%with the largest improvements in the least affectedmuscle groups [30]. However, there were nochanges in muscle strength assessed by the MMTor in fatigue.
Intensive resistance and aerobic exercise (P9 andP10) led to significantly improved aerobic capacityin children with JDM [37, 38]. The combination ofresistance and aerobic exercise improved muscle
function as assessed by RM and the ChildhoodMyositis Assessment Scale; however, there were noimprovements as assessed by the MMT [37], as thegroup had already achieved the maximum MMTscore at baseline.
Supplementation and exercise
Creatine supplements can further improve theeffects of exercise in patients with established PMand DM. One of the largest RCTs in the field ofexercise in myositis showed that creatine supple-ments in combination with resistive moderate-intensity home exercise (P1) 5 days a week for5 months resulted in significantly improved phys-ical capacity (aggregate functional performancetime measure including 50-foot walking time,Timed-up and Go and stair ascent–descend test),muscle function assessed by the MMT and Func-tional Index compared to the control group (exer-cise with placebo supplements) [22].
Effects of exercise on activity limitation, participation restriction andquality of life
The majority of studies have evaluated the effectsof exercise on activity and participation and/orquality of life using objective performance scores aswell as self-reported instruments after both resis-tance training and aerobic exercise or the twocombined (Table 2).
Most studies demonstrated improvements in objec-tively assessed activity limitation, such as walkingability and the ability to rise from a chair, inpatients with active and established PM/DM aswell as in those with IBM and JDM. Alemo Munterset al. [7] used a patient-preference instrument, theMcMaster Toronto Arthritis Patient Preference Dis-ability Questionnaire [46, 47], to assess activitylimitations and reported a within-exercise groupimprovement with no change in the control groupfollowing intensive aerobic and resistance exercise(P7). Further, they also showed that the exercisegroup improved significantly in the disease-specificMyositis Activities Profile [48] subscale MovingAround compared to the control group with addi-tional within-exercise group improvements in sub-scales/single items Household, Social and Leisureactivities [7]. A smaller RCT to evaluate a similarintensive aerobic exercise programme was alsoable to demonstrate significantly improved activitylimitation in the exercise group compared to thecontrol group [13, 14]. Mattar et al. reported a
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
ª 2016 The Association for the Publication of the Journal of Internal Medicine 17
Journal of Internal Medicine
significantly improved Health AssessmentQuestionnaire score [49] after training duringvascular occlusion (P4) [25], but not after a shorter3-week rehabilitation programme [17]. Earlier openstudies indicated that resistive home exercise (P1)could improve SF-36 [50] domains Physical Func-tion in patients with established PM/DM [15] andPhysical Function, Bodily Pain and Vitality inpatients with active, recent-onset disease [16].
Increased quality of life assessed by patients’ andparents’ Pediatric Quality of Life Inventory scales[51] was reported after intensive resistance andaerobic exercise in JDM patients (P10) [37]. Noother study has evaluated the effects of exercise onactivity and participation level or quality of life inpatients with JDM.
Long-term effects of exercise
Based on the finding of AlemoMunters et al. [7] thatonly muscle strength assessed by five VRM wasimproved at the 1-year follow-up compared to base-line, we assumed that regular exercise over longperiods of time are necessary to sustain as well as toachieve further improvements. This is supported bythe results of a study in patients with active PM/DMin which the exercise and control groups wereencouraged tocontinue toexerciseandbephysicallyactive during a 2-year follow-up period. Improve-ments in muscle endurance and aerobic capacitywere sustained up to the 1-year follow-up in bothgroups and up to the 2-year follow-up (intenstion-to-treat analysis) in the exercise group [9].
Discussion
Recent data suggest that intensive aerobic exerciseand resistance training can reduce disease activityand inflammation in patients with established PMand DM [7, 16, 23]. Exercise could be an effectiveanti-inflammatory treatment in patients with rheu-matic diseases, however the underlying mecha-nisms are not fully understood. Strength trainingor intensive aerobic exercise and resistance trainingmay reduce inflammation by increasing musclemass/decreasing fat mass, improving cardiovascu-lar and autonomic function and/or reducing levelsof pro-inflammatory and increasing levels of anti-inflammatory cytokines [52]. In fact, the notion thatexercise could increase inflammation has not beensupported by any published evidence. As demon-strated by Mattar et al. [26], three patients withrefractory PMandDMreceiving relatively highdoses
of glucocorticoids toleratedmoderate-to-high inten-sity resistance training and aerobic exercise, whichsupports the possibility that patients with recent-onset high disease activity could also exercise usinga similar exercise programme. However, it is impor-tant to adapt the exercise intensity to an individual’sdisease activity, oral glucocorticoid dose, fatigueand pain. Furthermore, it is important to initiateexercise at a low load/intensity and adapt activitiesto each individual patient with myositis, and thenslowly increase intensity. It is also recommendedthat exercise should be started under the supervi-sion of a physical therapist, and patients should befollowed up regularly to enable them to exercise atthe optimal level.
In several of the studies of exercise in myositis,patients improvedwith aerobic exercise/endurancetraining not only in terms of muscle endurance andaerobic capacity but also with regard to isometric ordynamic muscle strength [7, 13, 20]. An exerciseload of 40–50% of maximal strength is sufficient toimprove muscle strength in healthy sedentary indi-viduals, whereas further high-intensity strengthtraining is required to achieve the same result inmore physically active and well-trained individuals[53]. Patients with PMandDMhave reduced aerobiccapacity and muscle function compared to age-,gender- and physical activity-matched healthy con-trol subjects [7, 54] which probably explains thepositive nonspecific exercise response.
Exercise during vascular occlusion is a newapproach for patients with myositis. The rationalefor this type of exercise is a greater muscle fibrerecruitment resulting in a similar degree of hyper-trophy following low-intensity exercise duringpartial blood restriction as would be expectedfollowing high-intensity resistance training [55].Mattar et al. considered that patients with myositismight not be able to perform high-intensity resis-tance training due to poor muscle function. Thesame group described the feasibility of resistancetraining during vascular occlusion in a man withIBM showing improved muscle strength and qual-ity of life [35], and this type of exercise is now beingstudied in an RCT in Denmark. It would also beinteresting to test this type of exercise in patientswith recent-onset disease and receiving highglucocorticoid doses who might not tolerate high-intensity resistance training.
Results from the case study of exercise duringvascular occlusion [35], the resistance training
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
18 ª 2016 The Association for the Publication of the Journal of Internal Medicine
Journal of Internal Medicine
programme reported by Spector et al. [30] and the16-week home exercise programme performedtwice a day [33] are encouraging as there is noeffective medical treatment available for patientswith IBM. It seems that the most affected musclegroups such as the knee extensors and the fingerflexors have the least potential to improve, whichsupports the hypothesis that exercise should beinitiated as soon as possible following a diagnosisof IBM. However, as Johnson et al. [33] reported,improvements in strength and function even inpatients with severe muscle weakness support thenotion that all patients should exercise regularly. Itis not known whether the high frequency of twicedaily exercise is the effective component of thishome exercise programme. Clinical experiencefrom Karolinska University Hospital indicates thatpatients who can sustain twice daily home exerciseshow improvements in the most important activi-ties such as walking and the ability to rise from achair. This and other exercise programmes in IBMpatients need to be evaluated in larger controlledtrials.
Recent studies also increase understanding of theeffects of exercise in patients with JDM. Not only ismaximal aerobic capacity testing safe and feasible,but children with low disease activity tolerate long-term resistance and aerobic exercise. The results ofone study even suggested that disease activity wasreduced following exercise [37]. Habers et al. [42]reported that children with JDM have a reducedability to increase blood flow during a high-intensity exercise bout, indicating that treatmentshould be focused on improving circulation at restand during exercise. Endurance and aerobic exer-cise over months could provide such a treatment.Further studies are needed to evaluate the safetyand feasibility of exercise in patients with activeJDM and also to establish the effects of exercise in
all patients with JDM. There is also an urgent needto further investigate the effects of hand exercise inall patients with myositis. Patients with estab-lished PM and DM have significantly reduced gripstrength compared to normal values [27]. Thisfinding highlights the importance of assessing gripstrength and hand function to further reduceimpairments and activity limitations. In addition,there have been no studies to explore the effects ofhand exercise in patients with IBM.
At present, there is not enough evidence tosupport specific guidelines for exercise for adultswith PM or DM, and even less evidence forpatients with IBM and JDM. However, based onthe available data, it seems that recommendationsfor patients with myositis do not differ consider-ably from those for healthy adults (Table 4).Higher levels of muscle and cardiorespiratoryfitness are strongly associated with better healthoutcome. Furthermore, exercise according to rec-ommendations can reduce the risk of cardiovas-cular and metabolic diseases and osteoporosis inhealthy populations [56].
Summary
Current evidence supports the safety and efficacyof exercise to reduce impairments and activitylimitations and to improve quality of life in patientswith IIMs; indeed, intensive exercise could even beconsidered an anti-inflammatory treatment inadult patients with PM and DM. Recent studieshave demonstrated encouraging results for exer-cise, showing safety and improved function andquality of life also in patients with IBM and JDM.Exercise should be introduced for all patients withIIM individually adapted to disease activity, gluco-corticoid dose and the level of pain and fatigue.Exercise should be introduced at low loads and
Table 4 Recommendations for health-enhancing physical activity and exercise for healthy individuals
Duration of
exercise bouts,
min
Intensity,
percentage
of VRM
Intensity, percentage
of age predicted
maximal heart rate Frequency, times week �1
Increase muscle strength 2–3 – 60–80 –
Increase muscle endurance 2–3 – 30–40 –
Increase aerobic capacity 3 30–60 60–85
Improve/maintain health 4–7 30 – 50–70
VRM, voluntary repetition maximum. Ewing Garber et al. [56].
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
ª 2016 The Association for the Publication of the Journal of Internal Medicine 19
Journal of Internal Medicine
intensity under the supervision of a trained phys-ical therapist, and effects should be monitored byvalidated objective and patient-reported outcomemeasures. Further studies are needed to establishthe optimal type of exercise regimen in differentdisease phases and different subgroups of IIMswith respect to both clinical outcome measures andinflammation. The optimal physical activity level inpatients with myositis is another area that needs tobe studied.
Conflict of interest statement
No conflicts of interest were declared.
References
1 Gazeley DJ, Cronin ME. Diagnosis and treatment of the
Additional Supporting Information may be found inthe online version of this article:
Figure S1. Domains of the international classifi-cations of functioning, disability and health [4].
Figure S2. Easy to moderate home exercise pro-gram for patients with recent onset, active PM andDM. Numbers of repetitions and extra loads needto be adapted to individual muscle performance.The programme can be combined with 15-20minute walk on 50–70% of predicted maximalheart rate (220-age).
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
ª 2016 The Association for the Publication of the Journal of Internal Medicine 21
Journal of Internal Medicine
Figure S3. 10 VRM resistance training that can beemployed in patients with established PM and DM.A) Biceps and Latissimus dorsii, B) lower extremi-ties, C) Deltoids, D) Quadriceps. Perform each
exercise in 3 sets with a 90-sec rest in-between.Initiate the exercise on lower loads and progressslowly to goal intensity.
H. Alexanderson Review: Physical exercise as a treatment for adult and juvenile myositis
22 ª 2016 The Association for the Publication of the Journal of Internal Medicine
