Exercise improves strength and fitness in dermatomyositis and polymyositis, creatine kinase holds still throughout, and the gains need keeping up afterward.
Quick answerExercise improves muscle strength and fitness in dermatomyositis and polymyositis. Across nineteen studies the pooled effects were 0.61 and 0.82, and creatine phosphokinase held still, which is the outcome doctors worry about most. Hard weight training has now been tested directly, and it improved quality of life.
Two limits deserve your attention before you read this as settled. The pooled analysis rated its own certainty as low, because the studies were small and other differences between them weren't evenly spread. So the pooled numbers are the best available rather than the final word. Then there's the one-year follow-up of the hard training trial, where only muscle endurance still separated the groups, and the gains in strength and quality of life were no longer clearly different from controls. Read that as a reason to keep training, not as a sixteen-week course. Both trials took people whose disease was settled, so neither answers the question during a flare.
What the research found.
One analysis pooled nineteen separate studies of exercise in dermatomyositis or polymyositis, covering 298 patients between them. Exercise improved muscle strength at a standardized mean difference of 0.61, and it improved fitness at 0.82. No flares of the disease were reported anywhere across the nineteen studies pooled.
In that analysis, creatine phosphokinase showed no difference at all between the two groups. The standardized mean difference was minus 0.23, and the study puts the true value between minus 0.50 and 0.03. That interval just touches zero, which is why the finding reads as no difference.
da Silva and colleagues, Clinical Rheumatology, 2022
One trial ran sixteen weeks of hard weight training in thirty-two patients with settled myositis. The physical score on the SF-36, a general patient-reported quality-of-life questionnaire, improved by 5.33 points against controls. The study puts the true gain between 0.61 and 10.05, which is a wide interval around a real improvement.
At one year, muscle endurance still favored the training group, measured on the Functional Index 3. The difference was 10.7 points, on a true difference between 2.2 and 19.1. The gains in strength and in quality of life were no longer clearly different from controls by then, though they had improved inside the training group.
The movements, and the dose each one was tested at.
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Resistance training in myositis was avoided for years, and the reasoning behind that caution sounded sensible enough. This disease destroys muscle, creatine kinase marks the destruction, and loading a damaged muscle ought in theory to make it worse. Every trial that tested it went the other way instead.
One randomized controlled trial put thirty-two people with settled myositis through sixteen weeks of hard weight training against usual care. The SF-36 physical score improved by 5.33 points against controls, on a true gain the study puts between 0.61 and 10.05. Creatine kinase held still throughout, which is the outcome doctors worry about most.
This tier is bodyweight only, and it comes before the trial's own starting point rather than inside it. The trial enrolled people with established, settled disease and reasonably good baseline function. If a recent flare has left you weaker than that, build the patterns here first, and know that this tier is extrapolated rather than tested.
Sit back and down as if reaching for a chair behind you
Keep the chest lifted and the eyes forward
Knees track over the toes rather than collapsing inward
Push through the whole foot to stand
Myositis weakens the muscles closest to the trunk first, so standing from a chair is often the first thing to get hard. Use a higher seat and shorten the range if that is where you are. The pattern is what gets loaded in the weeks below, so it is worth owning before any weight goes on it.
Stand tall, then step one foot backward onto the ball of the foot
Lower the back knee toward the floor, both knees near ninety degrees
The front knee stays stacked over the ankle
Push through the front heel to return to standing
Balance is affected by weakness close to the trunk rather than by anything wrong in the feet. Hold a wall or a counter with one hand until it feels reliable. That is a sensible adjustment rather than a concession, and most people need it for the first few weeks.
Arms in a goalpost position, elbows at shoulder height
Press the hands straight overhead until the arms are extended
Lower back to the goalpost over two seconds
Keep the ribs down and the core braced
1:00
This is the trial's own starting intensity, at 70 percent of a one-rep maximum, trained twice weekly and supervised throughout. Retest your one-rep maximum every four weeks, as the protocol did. The safety result worth having, creatine kinase holding still, was produced under supervision during this part of the protocol.
Hold a dumbbell or kettlebell at the chest with the elbows tucked
The same squat pattern, controlled on the way down
Drive up with intent rather than grinding
Supervision is not a formality at this step, and the trial's clean safety record was produced with it. Weakness close to the trunk is compensated for in ways that are genuinely hard to feel from the inside. Somebody watching you squat notices what a program you run alone never will.
Pull the handle to the lower ribs with the elbows close in
Control the return rather than letting it snap back
1:30
Neither the exercises nor the structure changes at this step, and the load is the only thing that moves. It rises to 75 percent of a one-rep maximum, which is the middle of the three steps the trial ran. If your form breaks before the last repetition, the weight is too heavy.
Brace the core to protect the lower back as the load rises
1:30
This is the intensity the trial tested for its final eight weeks, at 80 percent of a one-rep maximum. It produced the gains, and creatine kinase did not rise. The protocol was tested in dermatomyositis, immune-mediated necrotizing myopathy and antisynthetase syndrome, and not in inclusion body myositis.
By week sixteen this is the working weight behind the trial's gains
Inclusion body myositis was not in the trial population, and this loading schedule has not been studied for it. If that is your diagnosis, the schedule above is not evidence about you. Take it to your rheumatologist and build something individual instead.
1:30
Aerobic work appears across the nineteen studies pooled into one analysis, and the direction was consistent across all of them. The pooled effects came out at 0.61 and 0.82. Those authors graded their own certainty as low, because myositis is rare and every study feeding the pool is small.
Nothing here is a reason to skip the cardiovascular side of this. The evidence is thinner than the resistance evidence, and it points in one direction. What no trial has done is test high-intensity intervals in myositis, so that tier says so rather than borrowing a protocol.
This one hasn't been filmed yet.
Walking, stationary cycling or swimming, whichever the joints tolerate
You should be able to hold a conversation but not sing
Start at fifteen minutes if deconditioned and build over four to six weeks
Interstitial lung disease changes this question rather than answering it, and it is common in antisynthetase syndrome. Get the cardiac and pulmonary side cleared first if that applies to you. Swimming and cycling ask less of the joints than running does, which is the reason they lead the list.
Where the evidence doesn't exist
No trial has tested high-intensity intervals in myositis, which is an absence rather than thin data. Rheumatoid arthritis has a dedicated trial for this and myositis does not. So nothing on this tier is a myositis protocol, and anything you do here is a cautious reading of general exercise physiology.
This one hasn't been filmed yet.
Consider it only once resistance training is established and disease is settled
Get cardiac and pulmonary clearance first if there is any lung involvement
This is a bridge rather than a prescription
No exercise snack trial has been run in myositis, so this tab borrows its reasoning from the wider autoimmune literature. Sedentary time raises cardiovascular risk on its own. That transfers without myositis-specific proof, and it is worth knowing which of the two you are being given here.
This one hasn't been filmed yet.
Stand fully and sit back down ten times from your chair
Contracting muscle pulls glucose from the blood without needing insulin
1:00
This one hasn't been filmed yet.
Walk briskly across the room and back, three times
Restoring blood flow supports the lining of the vessels
1:30
This one hasn't been filmed yet.
The same patterns as the foundation tier, done as a short break
1:00
What the trials found
Exercise in inflammatory myositis was avoided for a long time, and the fear behind that avoidance sounded perfectly reasonable. This disease destroys muscle, creatine kinase marks that destruction, and so loading a muscle ought in theory to make things worse. The trials went the other way instead, and that fear now has a clear answer.
One 2022 analysis pooled nineteen studies covering 298 patients with dermatomyositis or polymyositis. Muscle strength improved at a standardized mean difference of 0.61 and fitness improved at 0.82. Creatine phosphokinase showed no difference between the groups, coming in at minus 0.23, with the study putting the true value between minus 0.50 and 0.03. No flares of the disease were reported anywhere in those nineteen studies.
How firmly to hold those numbers
The review authors graded their own certainty as low, and they were right to do that. Myositis is rare, so the individual studies feeding that pooled figure are all small ones. The analysis also flagged why it downgraded them, which is that other differences between the studies weren't evenly spread across the groups being compared. Pooling small studies gives you a number that inherits every weakness of what went into it.
What survives that caution is the direction of the effect, and the safety finding underneath it. Several small studies pointed in one direction on strength and on fitness, not one of them showed a creatine kinase signal, and not one reported a flare. That's a consistent picture even with the size of the effect still uncertain. It's enough to have changed the default advice from rest to supervised activity, which is what has happened in practice.
Testing hard training directly
The next question is the obvious one, which is how hard people with myositis can train. One randomized controlled trial went straight at that question. Thirty-two patients with settled myositis were split into two groups, one doing sixteen weeks of hard weight training and the other continuing usual care. The main outcome was the physical score on the SF-36, a general patient-reported quality-of-life questionnaire, which improved by 5.33 points against controls, on a true gain the study puts between 0.61 and 10.05.
Muscle endurance improved too, measured on the Functional Index 3, where it rose by 11.49 points against controls. Muscle testing rose by 1.30 points on the same comparison. Disease activity didn't rise and creatine kinase didn't spike anywhere in the sixteen weeks. What that amounts to is one trial of thirty-two people with settled disease, and it's also the most direct evidence anybody has on training intensity in this condition.
The one-year follow-up, which changes the reading
Those investigators followed the patients for a year afterward, and the results are more instructive than the trial itself. Muscle endurance still favored the training group by 10.7 points on the Functional Index 3. The study puts the true difference somewhere between 2.2 and 19.1 points on that scale, which is a wide interval around a real difference. Inside the training group, both quality of life and muscle testing had improved over the year.
At a year those gains were no longer clearly different from the control group at all. That's the part most summaries of this trial leave out, and it's also the part with practical consequences for anybody deciding what to do next. Endurance held on and the rest of it faded away. That points at training as something you keep doing rather than a sixteen-week course you finish.
Practical points
Supervision turns up in most myositis exercise programs, and the reason for that is worth understanding. This disease weakens muscle groups unevenly, and it usually hits the muscles closest to your trunk hardest of all. The ways people compensate for that are genuinely hard to see from the inside, because compensating is what a body does without asking you first. A physiotherapist watching you squat or step up will notice things that a program you run yourself never will.
The trials on this page took people whose disease was settled, so they don't tell you what to do while it's active. Swallowing and breathing muscles are a separate worry, and no exercise trial here looked at either one. Your rheumatologist has your creatine kinase trend and your current examination in front of them, and those are the inputs a decision about flares really needs.
Questions patients ask.
Will exercise damage my muscles or raise my CK?
The pooled evidence on this says no to that worry. Creatine phosphokinase showed no difference between the exercising and control groups, at a standardized mean difference of minus 0.23 on an interval crossing zero. That's the exact fear behind decades of advice to rest in myositis, and it hasn't held up. Do mention a real change in weakness or swallowing to your team, because training soreness feels different and the two are easy to confuse.
How much does exercise improve strength?
The pooled effect on strength across nineteen studies was 0.61, which counts as a moderate effect. Fitness improved by 0.82 across that pooled set of studies. The review authors graded their own certainty as low, because the studies were small and other differences between them weren't evenly spread, so the direction is consistent while the size is less firm than the numbers look.
Is hard training safe in myositis?
It has now been tested directly, in one trial. That trial took thirty-two people with settled disease and ran for sixteen weeks, where quality of life improved against controls, and so did muscle endurance and muscle testing. Disease activity didn't rise and creatine kinase didn't spike. That's one trial in a small group with settled disease, which is the group it speaks for, and it doesn't answer the question during a flare.
Do the improvements last?
Partly, and the honest answer here is worth having. A year after that trial, muscle endurance still favored the training group by 10.7 points on the Functional Index 3. The gains in strength and quality of life were no longer clearly different from controls by then, so these gains need continued training to hold, which is true of exercise in general.
Should I exercise during a myositis flare?
Both trials on this page took people whose disease was settled, so neither tells you what to do while it's active. That's a real hole in the evidence rather than a reason to assume either answer. Your rheumatologist knows your creatine kinase trend, your current strength, and whether your swallowing or breathing muscles are involved, so ask before training through a flare.
What kind of exercise should I be doing?
Resistance work and aerobic training both have evidence behind them here. The trial with the most direct evidence used supervised resistance work, and supervision turns up in most of these programs for good reason. Myositis weakens some muscle groups more than others, and a physiotherapist can see that. If supervision is hard to get, tell your team so they can adapt it rather than dropping the idea.
References.
da Silva BISL; Dos Santos BRJ; Carneiro JA et al. Physical exercise for dermatomyositis and polymyositis: a systematic review and meta-analysis. Clinical rheumatology. 2022;41:2635-2646. 10.1007/s10067-022-06281-1SR + MA
Jensen KY; Aagaard P; Suetta C et al. High-intensity resistance training improves quality of life, muscle endurance and strength in patients with myositis: a randomised controlled trial. Rheumatology international. 2024;44:1909-1921. 10.1007/s00296-024-05698-yRCT
Jensen KY; Aagaard P; Suetta C et al. High-intensity resistance training in patients with myositis - 1-year follow-up on a randomised controlled trial. Rheumatology international. 2025;45:104. 10.1007/s00296-025-05858-8RCT follow-up
This page gathers the published research on this subject into one place. The studies behind
it were published between 1989 and 2026, and every figure
links to the paper it came from. Those studies were peer reviewed. This summary of them was
not. Dr. Sarah Luebker is reviewing these pages one at a time and has not reached this one yet,
so it carries no medical review date and nothing here is her opinion or her advice to you. Each
page gets updated as she reaches it. It is here in the meantime because the science is worth
having in one organized place that is easy to find and easy to read.
Talk to your own clinician before acting on any of it.
