Spasticity is when your muscles become stiff, making it hard to move. It can happen to any part of your body, but it most commonly affects your legs. It can range from having a little stiffness to a total inability to stand or walk.

A minor case of spasticity might involve a feeling of tightness or tension. But severe spasticity can be painful and incapacitating.

Sometimes spasticity involves muscle spasms. A spasm is a sudden, involuntary jerk, muscle contraction, or muscle tightening. Changing positions or making sudden movements can bring on a spasm. So can extreme temperatures or tight clothing.

Spasticity affects about 60 to 84 percent of people with multiple sclerosis (MS). For some, it’s an infrequent symptom that passes quickly. For others, it can be unpredictable and painful.

These are the two most common types of spasticity in MS:

  • Flexor spasticity. This type affects the muscles on the back of your upper legs (hamstrings) or the top of your upper thighs (hip flexors). It’s an involuntary bending of the knees and hips toward your chest.
  • Extensor spasticity. This type involves the muscles on the front (quadriceps) and inside (adductors) of your upper legs. It keeps your knees and hips straight but pressed together — or even crossed — at your ankles.

You can have one or both types. They’re treated the same way. You can also experience spasticity in your arms, but it’s not as common in people with MS.

If spasticity is becoming a problem, you’ll need to work with your doctor to create a treatment plan.

The goal is to relieve symptoms like muscle contractions and pain. Easing symptoms should help improve motor skills and your ability to move freely.

Your doctor will probably start out by suggesting simple stretching and other supportive activities, which may include:

  • yoga
  • progressive muscle relaxation
  • meditation and other relaxation techniques
  • massage

Certain things can trigger symptoms or make them worse. Part of your treatment plan should include identifying triggers to help you be better able to avoid them. Some common triggers are:

  • cold temperatures
  • humid conditions
  • tight clothing or shoes
  • poor posture
  • bacterial or viral infections like a cold, bladder infection, skin sores, or the flu
  • constipation

Your doctor may refer you to other healthcare professionals like physical or occupational therapists.

Depending on the severity of your symptoms, you may also consider:

  • medications to reduce muscle stiffness
  • orthotic devices, like braces and splints, to help with positioning
  • surgery to sever tendons or nerve roots

Medications can be used to treat MS-related spasticity. The goal of medication is to lessen muscle stiffness without weakening muscles to the point where you can’t use them.

Whatever medication your doctor prescribes, they’ll probably initially start you off with a low dose. If needed, they can gradually increase the dose until you find the one that works well.

Two antispasticity drugs used to treat MS are:

  • Baclofen (Lioresal). This oral muscle relaxant targets nerves in the spinal cord. Side effects may include drowsiness and muscle weakness. For more severe spasticity, it can be administered using a pump implanted in your back (intrathecal baclofen).
  • Tizanidine (Zanaflex). This oral medication can relax your muscles. Side effects may include dry mouth, muscle weakness, sleepiness, and lower blood pressure.

If neither of these medications works, there are some other options. They can be effective, but some side effects can be serious:

  • Diazepam (Valium). This treatment option is not preferred because it can be habit-forming and sedating.
  • Dantrolene (Ryanodex). It can cause liver damage and blood abnormalities.
  • Phenol. This nerve blocker can cause burning, tingling, or swelling. In rare cases, it can cause motor weakness and sensory loss.
  • Botulinum toxin (Botox). This is administered via intramuscular injection. Side effects may include injection site soreness and temporary weakening of the muscle.

There is ongoing research and interest in the use of medical cannabis to treat spasticity.

In a 2014 review, the American Academy of Neurology found strong evidence to support the use of cannabinoids to reduce pain in people with MS-related spasticity. Other, more recent research have supported this finding.

Speak with your doctor about which medication option is right for you.

Regardless of whether you use medication, it’s important to include movement in your treatment plan.

Even if you plan to exercise on your own, it might still be a good idea to work with a physical therapist first. They can assess your strengths and weaknesses to help determine which exercises are most likely to help. Then they can show you how to do these exercises properly.

If you have trouble performing routine tasks like dressing, you might want to consider working with an occupational therapist. They can teach you how to use assistive devices and make home modifications to make doing tasks easier.

Assistive devices, also called orthotic devices, can help keep your legs in the proper position so it’s easier to move around. Talk with your doctor or physical therapist before purchasing an orthotic device. If it doesn’t fit well or isn’t well made, it can make spasticity worse and lead to pressure sores.

Some assistive devices that can help manage spasticity include:

  • splints
  • braces
  • canes
  • walkers
  • wheelchairs
  • orthotic insoles

These devices can help you maintain balance, support your weight, and minimize fatigue by making walking and other everyday activities less taxing.

Because surgery always carries some risk, it’s usually a last resort. Surgery for spasticity involves cutting tendons or nerve roots to relax stiff muscles. This is generally effective in treating spasticity, but it’s irreversible.

If you’re experiencing spasticity or occasional muscle spasms, you should mention it to your doctor or neurologist at your next visit, even if it’s not a big problem.

If spasticity is painful or interferes with certain movements, consult with your doctor now.

Without treatment, severe spasticity can lead to:

  • prolonged muscle tightness and pain
  • pressure sores
  • frozen and disabled joints

Early treatment can help you prevent these complications.

In some cases, a small degree of spasticity may be useful. For example, if your leg muscles are so weak that it’s hard to walk, a little spasticity can help you. But severe spasticity can interfere with your quality of life.

As with other symptoms of MS, spasticity can vary in degree and frequency. With treatment, it increases the likelihood of relieving pain and stiffness and improving function.

You can work with your doctor to create the right treatment plan and adjust it as your needs change.