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Understanding spasms and stiffness

Muscle stiffness and spasms are common MS symptoms, and are often described as 'spasticity'.

What are spasms and stiffness?


Spasticity means there is an increase in 'muscle tone' (resistance or tension in the muscle).

In other words, when the muscle is moved, there is more resistance to this movement than there normally would be. Muscles feel more rigid.

Health professionals sometimes talk about 'spasticity' when describing the muscle stiffness.


Increased tone (resistance in the muscle) can mean muscles are slow to relax, and this can cause stiffness.

Depending on the muscles affected, this stiffness can make it difficult to perform delicate movements with the hands and fingers, or make larger movements difficult, which can affect walking, for example.


When affected muscles stretch, spasticity may also cause them to twitch or jerk in an uncontrolled way – a spasm. If muscles twitch or jerk repeatedly, this is known as 'clonus', for example when a foot taps repetitively on the floor.

Some people with MS experience other spasms - sudden involuntary movements that can make the arms or legs move in different ways.

These can occur even without the muscle being stretched.

Causes and triggers

Muscles are involved in every movement you make. They get longer and shorter to move and hold the body.

If MS causes nerve damage that affects muscle movements, they can cause a range of problems.

Recognising trigger factors

Investigating potential trigger factors that cause or make your spasms or stiffness worse is a vital step in finding solutions. If you know what is causing the problem, then this can help you deal with it.

For example, something as simple as loosening tight clothing might provide some relief.

The following are some of the more common trigger factors that you and your doctor or MS nurse might consider:

  • an increase in your body temperature (perhaps because of a fever or too much exercise)
  • infections (for example, bladder or chest infections)
  • if you are experiencing a relapse
  • skin irritation (including pressure sores)
  • a full bladder
  • constipation, causing a full bowel
  • overly tight strapping or clothes
  • pain
  • a fractured bone (perhaps caused by a fall)
  • problems with posture
  • emotional stress

The effects of spasms and stiffness

Spasms and stiffness can range from a minor annoyance to problems that make daily life and activities uncomfortable, painful and difficult.

Extremely strong spasms can jerk the body quite dramatically, causing limbs to move with considerable force, or be held in uncomfortable positions.

Night-time muscle twitching

Spasms sometimes cause particular problems at night. The 'jerking' they can cause to the body – often the legs – might wake you or your partner several times a night.

Not getting a good night's sleep can make living with MS more difficult, possibly making other symptoms worse, such as fatigue and weakness.


Both muscle spasms and stiffness can be painful, though they are not always. You might feel the dull ache of stiff muscles, or a sharper pain if they spasm.

Muscle problems can also interfere with good posture, causing back pain, for example. If pain is an issue for you, let your doctor or MS nurse know.

Find out more about managing pain

Stiffness having a positive effect

If your leg muscles are weak, for example, a certain amount of stiffness can help keep the legs rigid and stable for walking and standing. If this is the case, it may be better to monitor the situation to prevent further complications, rather than try and remove the stiffness completely.