Strength in myositis: what training can and cannot give you back

In stable, treated inflammatory muscle disease, exercise is safe and builds real strength. Inclusion body myositis needs a more honest set of expectations.

Week of July 10, 2026 — Angelo Papachristos PT, ACPAC

Maria is 52, two years into dermatomyositis, stable on methotrexate with a low dose of prednisone. She came in with a folded flyer for a strength class tucked into her file and her latest bloodwork sitting on top of it, and she wanted one answer: if she started lifting weights, would she wake the disease back up? Someone had told her early on to rest and protect her muscles, and she had been quietly afraid of exercise ever since.

The advice to rest has done real harm

For a long time, people with inflammatory myopathy, the family of diseases that includes dermatomyositis (a myositis with skin involvement), polymyositis, and immune-mediated necrotizing myopathy, were told to avoid exertion. The logic sounded reasonable. The muscle is already inflamed, so why add load to it. And exercise can nudge up creatine kinase, or CK, the muscle enzyme in the blood that clinicians watch as a rough marker of muscle damage.

That advice backfired, and I will say it plainly. Rest layered deconditioning on top of the disease. Deconditioning weakness is easy to mistake for the myositis itself, so patients ended up weaker than the disease alone would ever have made them, and then that extra weakness got blamed on the illness. Maria had spent two years avoiding the one thing that would have helped.

What actually happens when people with myositis train

The turnaround came largely from a group at the Karolinska Institute led by physiotherapist Helene Alexanderson, who spent two decades testing whether exercise is safe here rather than assuming it was not. In one of the more convincing studies, Nader, Alexanderson and colleagues (Molecular Medicine, 2010) put patients through a resistance program and took muscle biopsies before and after. Loading the muscle did not increase inflammation. The gene activity in the muscle shifted toward building tissue and away from inflammatory signalling.

Endurance work holds up too. Alemo Munters and colleagues (Arthritis Care & Research, 2013) ran a multicentre trial of aerobic exercise in people with established polymyositis and dermatomyositis and found improved aerobic capacity and better muscle metabolism, with no worsening of disease activity. Across this body of work, summarized in Alexanderson's reviews, the consistent finding is that in stable, treated disease, genuine gains in strength and stamina are achievable.

About that CK number Maria kept looking at. Exercise can bump CK up temporarily in anyone, and a modest rise after starting a program is not, by itself, a flare. Your team reads CK alongside how you feel and how you test, never in isolation.

One honest limit on all this: the green light is for controlled disease. If you are newly diagnosed with active, uncontrolled inflammation, the early work is usually gentle range of motion with a physiotherapist while the medication takes hold, and heavier loading waits until things settle. The safety evidence is about stable disease, not an active severe flare.

Inclusion body myositis is a different conversation

Inclusion body myositis, or IBM, sits apart from the rest. It is a slowly progressive muscle disease that, unlike the others, does not respond to immunosuppression, and it has a signature pattern, striking the thigh muscles that straighten the knee and the muscles that bend the fingers.

Honesty matters most here. Exercise in IBM is safe, and studies including Johnson and colleagues (Journal of Clinical Neuromuscular Disease, 2009) and Alexanderson's home-based programs show people can improve aerobic fitness and hold onto function. What exercise will not do in IBM is reverse the disease or rebuild what has already gone. The goal is to slow the loss and protect the function you still have. That is a goal worth pursuing. Stopping tends to speed the decline, so "it won't cure it" is the wrong reason to walk away from a program.

How to tell it is working

This is where I steered Maria away from her bloodwork. CK is not the scoreboard for progress. Function is. Ask your team for a baseline set of measures you can repeat over time: manual muscle testing, where a clinician grades specific muscle groups, plus timed functional tests such as how many times you can rise from a chair in 30 seconds, how long a short walk takes, or how far you get in a six-minute walk. Then you track against your own baseline, not against anyone else's.

Two practical points. Progress is slow, measured over months, so a simple written log of chair-stands or walking distance will show you change that a single session never will. And strength and endurance do not rise together, so a good program builds both and measures both. Someone can regain leg strength while their stamina lags behind, or the reverse. There is even early biological support for starting sooner once disease is controlled: research on myostatin, the body's own brake on muscle growth, suggests its regulation is most disturbed around disease onset (Arthritis Research & Therapy, 2026), which fits the case for loading muscle early rather than waiting.

What to do, and the conversation to have

Bring the exercise question to your rheumatologist and ask for a referral to a physiotherapist who knows inflammatory muscle disease, ideally to set a baseline of functional tests and a graded plan. Start supervised if you can, begin lighter than you think you need to, and add load gradually.

If your disease is controlled, the plan should include both resistance and aerobic work, and it should be progressed over time rather than left static for months. If you have IBM, keep going with realistic goals: maintaining function is a win.

Questions for your care team

Is my disease stable enough right now to add resistance training, and at what starting intensity?

Can we record a baseline of functional measures, like a 30-second sit-to-stand and a walk test, so we can track real change?

Do I have inclusion body myositis or a treatment-responsive type, and how should that change what I expect from exercise?

What size of CK change would actually concern you, versus what you would expect after I start exercising?

Between visits, track a simple weekly log of one repeatable function test (chair stands or walking), your fatigue level, and any new or spreading weakness, and bring it to each appointment.

What this does not mean

Exercise is an add-on to your medication, not a substitute for it, and none of this is a reason to lower or stop immunosuppression on your own. A true flare with new or spreading weakness is a reason to call your team, not to push through the next session.

References

Nader & Alexanderson 2010 - resistance exercise, muscle biopsy and mRNA in myositis. Nader GA, Dastmalchi M, Alexanderson H, et al. A longitudinal, integrated, clinical, histological and mRNA profiling study of resistance exercise in myositis. Molecular Medicine, 2010.

Alemo Munters 2013 - endurance exercise in established PM/DM. Alemo Munters L, Dastmalchi M, Andgren V, et al. Improvement in health and possible reduction in disease activity using endurance exercise in patients with established polymyositis and dermatomyositis. Arthritis Care & Research (Hoboken), 2013.

Alexanderson - review of exercise in inflammatory myopathies including IBM. Alexanderson H. Exercise in inflammatory myopathies, including inclusion body myositis. Current Rheumatology Reports, 2012.
https://pubmed.ncbi.nlm.nih.gov/22467380/

Johnson 2009 - aerobic exercise in sporadic inclusion body myositis. Johnson LG, Collier KE, Edwards DJ, et al. Improvement in aerobic capacity after an exercise program in sporadic inclusion body myositis. Journal of Clinical Neuromuscular Disease, 2009.

Myostatin regulation at IIM onset and muscle outcomes 2026. Alterations in systemic and skeletal muscle myostatin regulation are most prominent at disease onset and associate with muscle-related outcomes in idiopathic inflammatory myopathies. Arthritis Research & Therapy, 2026.

This article is for education only and is not medical advice. It cannot account for your individual diagnosis, disease activity, or other conditions. Decisions about exercise and medication in myositis should be made with your own rheumatology and physiotherapy team.

Angelo Papachristos PT, ACPAC — Advanced Practice Physiotherapist— Co-Founder, RheumAcademy — Co-Founder, Arthros Inc.

Strenght and Myositis