Why Do Muscles Become Weak in Rheumatoid Arthritis, and Can EMS Stop This Process? Japanese & Swedish Scientists Studied This

person Savannah Martin
calendar_today Jan 19, 2026
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Welcome to another post from the ORIEMS FIT Research Digest, where we break down real scientific studies into simple, clear language.

Our mission is simple:
share interesting research, spark curiosity, and help you explore science yourself.

At the end of every post, you’ll always find the original study link.
If you love collecting research papers or checking facts, you can go straight to the source.

Who Did This Research and When?

This study was published in 2017 in PLOS ONE, one of the world’s most respected peer-reviewed scientific journals.

Researchers came from:

Sapporo Medical University – Japan
Hiroshima University – Japan
Okayama Prefectural University – Japan
Karolinska Institutet – Sweden (one of the world’s top medical universities)

These institutions are well-known for muscle, physiology, and medical research.

Who funded the study?

Japan Society for the Promotion of Science
Swedish Research Council
Arthritis and rheumatology research foundations

This tells us the study was independent, peer-reviewed, and publicly funded.

What Is This Research About?

People with arthritis often suffer from muscle weakness, not just joint pain.

This study asked a simple question:

Can neuromuscular electrical stimulation (NMES) protect muscles from weakening during arthritis?

Who Was Studied?

This was a controlled laboratory study using rats with arthritis-like inflammation.

Why rats?
Because their muscle structure and muscle chemistry are very similar to humans, especially in early research.

Which Method Was Used?

Arthritis was induced in the knee joints
Muscles became weak and inflamed
One group received neuromuscular electrical stimulation (NMES)
NMES was applied every second day for 3 weeks
Stimulation targeted leg muscles using surface electrodes

What Did the Researchers Find?

1. Arthritis caused major muscle weakness

Muscle force dropped sharply
Even when muscle size stayed the same
This showed muscle quality was damaged, not just size

2. NMES prevented muscle strength loss

is only related to Muscles receiving NMES kept their strength
At high stimulation levels, muscle force returned close to normal
This happened without making arthritis worse

3. NMES protected muscle proteins

Arthritis caused muscle proteins to:

Clump together
Lose structure
Stop working properly

NMES stopped this damage.

Specifically:

Actin protein aggregation was reduced by over 50%
Desmin protein damage was prevented
Muscle structure stayed more organized

4. NMES reduced harmful oxidative stress

Arthritis increased enzymes that create damaging molecules.

NMES:

Reduced NOX2 and nNOS enzymes
Lowered oxidative stress inside muscles
Helped muscles function normally again

5. NMES restored the muscle clean-up system

Arthritis disrupted autophagy (the muscle’s internal recycling system).

NMES:

Reduced toxic protein buildup
Restored normal protein turnover
Helped muscles stay healthier

Why Could EMS Be Helpful?

This research suggests EMS may:

Support muscles during inflammation
Help muscles stay active when movement is difficult
Protect muscle quality, not just size
Support muscle recovery without heavy exercise

How Might This Help EMS Users?

For people who:

Can’t exercise normally
Have joint pain
Experience muscle weakness
Sit for long hours
Are recovering or resting

EMS may help keep muscles engaged and responsive, even with limited movement.

Research Paper Details

Original Research Name:
Neuromuscular electrical stimulation prevents skeletal muscle dysfunction in adjuvant-induced arthritis rat

Simplified Name:
Can Electrical Muscle Stimulation Protect Muscles During Arthritis?

Published In:
PLOS ONE (Peer-Reviewed Open-Access Journal)

Original Study Link:
https://doi.org/10.1371/journal.pone.0179925

PLOS ONE is a globally trusted scientific publisher with strict peer-review standards.

Quick Study Summary Table

Topic	Key Finding
Muscle strength	Preserved with NMES
Protein damage	Reduced by over 50%
Oxidative stress	Lowered with NMES
Muscle structure	Protected
Arthritis severity	Not worsened
Study duration	3 weeks

Let’s Talk

Did you expect muscle weakness to come from protein damage, not muscle size?
Leave a comment and share what surprised you most.

Mandatory Disclaimer

This blog post is for informational and recreational purposes only and does not constitute medical advice.
Always consult with a healthcare professional before starting any new treatment.

Full disclaimer:
https://oriems.fit/blogs/research-digest/disclaimer