How Your Muscles Are Affected in MS

When your nerves go awry, your muscles are affected

muscular pain
 People Images/istock

Think of your muscles as puppets on a string. The puppet (your muscle) cannot move without the strings (your nerves) guiding it. The hand that is controlling the puppet is your central nervous system (your brain and your spinal cord).

In multiple sclerosis (MS), damage to nerve fibers in the central nervous system impairs the signaling that occurs between your nerves and muscles. In other words, the strings of the puppet aren't working well enough to properly move the puppet. As a result, muscle weakness, spasticity, and a loss of coordination may occur.

Let's explore these muscle symptoms in a bit more detail, including how you (or your loved one) can best cope with them.

Weakness in MS

Muscle weakness in MS is more than simply having a lack of energy or not having the strength to lift a heavy dumbbell; rather, it's a true difficulty moving your muscles, almost like they are too wobbly or tired to work.

While muscle weakness can occur anywhere within the body, it's most noticiable in the limbs.  Weakness in the arms and legs can be quite disabling, too, as it can lead to problems walking, showering, dressing, and completing other basic activities of daily living.

One common example of a complication of muscle weakness in MS is foot drop, which means you cannot lift the front part of your foot. Foot drop occurs as a result of poor nerve signaling to the muscles used to flex your foot. To compensate for this symptom, a person may drag their toes or adopt a certain walking pattern, like swinging their leg out.


Coping with muscle weakness first entails teasing out the source—whether it's coming from the disease itself (from demyelination of nerves in the brain and/or spinal cord) or from a lack of use. If your muscle weakness stems from MS, then muscle strengthening with weights (called resistance training) will not be helpful; in fact, they may worsen your weakness.

The best thing you can do is find a physical therapist who has experience working with patients with MS. A physical therapist can help you figure out which muscles have impaired nerve signaling and which ones have healthy signaling. This way you can learn to strengthen and maintain the tone of the muscles that are receiving proper nerve signals.

A physical therapist can also recommend assistive devices. For example, an ankle-foot orthotic is often used to treat foot drop in MS. It's also a good idea to obtain a referral from your doctor for an occupational therapist—someone who can help you devise a home and/or work environment that is safe and optimizes muscle energy conservation.

Lastly, if your muscle weakness does stem from disuse (perhaps you have disabling fatigue or are in a wheelchair), then strengthening your muscles through a weight-training and exercise program can be helpful.

Likewise, it's important to treat the cause behind your muscle disuse, if possible. For instance, if fatigue is the culprit than you may consider better sleep habits, energy conservation strategies, or even taking a prescription medication like Provigil (modafinil) or Ritalon (methylphenidate). Exercise can help fatigue, as well—a double bonus (you get to strengthen your muscles and feel better at the same time).

Spasticity in MS

In MS, increased muscle tone or muscle tightness (called spasticity) occurs as a result of demyelination (loss of myelin sheath) in the pathways that carry motor (movement) signals from the brain. Due to these damaged pathways, nerve signaling to the muscles is slowed, which can cause a person's muscles to harden and clench up on their own.

As a result of spasticity, the muscles may spasm and/or become rigid and stiff—and this can be quite painful. Over time, a person may stop using certain muscles due to spasticity, and this can lead to muscle atrophy (when a muscle wastes away, appearing smaller).

Likewise, with severe stiffness, a person can develop contractures—when a joint becomes frozen in place, due to shortening of the muscle.

Contractures can then lead to the formation of pressure sores, also called bed sores, from being confined to a sitting or lying position. Pressure sores are very serious and may become life-threatening if they become infected.


Unlike muscle weakness, there are medications that can ease spasms and stiffness, and they work by relaxing the muscles. Some of these medications include:

  • Muscle relaxants like baclofen and Zanaflex (tizanidine)
  • Benzodiazepines like Valium (diazepam)

The downside of these medications is that they may cause tiredness or muscle weakness.

Other medical options include the anticonvulsant Neurontin (gabapentin), Botox injections (which go directly into the muscle), or a baclofen pump (located in a person's abdomen).

In combination with, or in lieu of medication, rehabilitation with a physical and occupational therapist is a key component to managing spasticity in MS. A rehabilitation therapist can teach you (or your loved one) specific stretching exercises, as well as how to prevent contractures.

In addition to rehabilitation therapy, alternative therapies are often used to cope with spasticity. Some of these alternative therapies include marijuana, yoga, massage, and biofeedback.

Lastly, avoiding (or minimizing) triggers of spasticity is important—common ones being excessive heat, a rise in your body's internal temperature (for example, fever), a full bladder, and irritating or tight clothes. Treating infections promptly (like a urinary tract infection) and pain can also help prevent muscle spasms and stiffness.

Loss of Coordination in MS

A loss of coordination, or balance, in MS stems in large part from muscle problems, especially muscle weakness and spasticity. Other MS-related factors that contribute to a loss of coordination are blurry vision, vertigo, and sensory problems, like numbness in the legs.

One of the biggest concerns with a loss of coordination is falling. This is because with balance problems, a person may adopt a swaying, clumsy walking pattern (called ataxia).

According to a large analysis, in Multiple Sclerosis, of people with MS (across a broad age range and disease severity), the average fall rate is approximately one fall per month, which seems pretty high and worrisome.

Other research has shown that about 50 percent of middle to older aged people with MS experience at least one fall over a six month period.


Treating balance problems in MS involves a thorough examination by your doctor to decipher the primary cause. For example, if muscle weakness is the likely culprit behind your loss of coordination,  then an assistive device like a cane or walker may be useful, as well as performing exercises that strengthen certain muscles in your legs and trunk.

Even more, an exercise program will not only improve your muscle strength, but research shows it can also improve other symptoms of MS like fatigue, depression, and cognitive problems.

An occupational therapist can also work with you to ensure your home is safe and fall friendly, as a result of your balance issues. Ideas may include getting rid of loose rugs, ensuring lighting is adequate, and installing handrails.

A Word From Verywell

While multiple sclerosis is a nervous system disorder, there is a downstream effect on your muscles, which can lead to debilitating, even painful symptoms. But the good news is that with rehabilitation (and sometimes medication), you can get relief.

In the end, even if you are experiencing only mild muscle symptoms, it's reasonable to talk with your doctor about seeing a physical therapist. You may be surprised how soothing and effective just a few strategies and exercises geared towards your unique muscle symptoms can be.


Was this page helpful?
Article Sources
  • Birnbaum, M.D. George. 2013. Multiple Sclerosis: Clinician’s Guide to Diagnosis and Treatment, 2nd Edition. New York, New York. Oxford University Press.
  • Correia de Sa J et al. Symptomatic therapy in multiple sclerosis: a review for a multimodal approach in clinical practice. Ther Adv Neurol Disord. 2011 May;4(3):139-68.
  • Moradi M et al. Effects of eight-week resistance training program in men with multiple sclerosis. Asian J Sports Med. 2015 Jun;6(2):e22838.
  • National MS Society. Weakness. Spasticity and MS: Management Strategies.
  • Nilsagard Y et al. Falls in people with MS—an individual data meta-analysis from studies from Australia, Sweden, United Kingdom and the United States. Mult Scler. 2015 Jan;21(1):92-100.