Muscle stiffness is when your muscles feel tight and you find it more difficult to move than you usually do, especially after rest. You may also have muscle pains, cramping, and discomfort.

This is different from muscle rigidity and spasticity. With these two symptoms, your muscles stay stiff even when you’re not moving.

Muscle stiffness usually goes away on its own. You may find relief with regular exercise and stretching. In some cases, muscle stiffness can be a sign of something more serious, especially if there are other symptoms present.

Causes

There are a variety of things that can cause muscle stiffness, including:

A common cause of muscle stiffness is exercise or hard physical labor of some kind.

Often, stiffness can occur when someone starts a new exercise routine or program or has increased the intensity and duration of their routine.

When this happens, the muscles are required to work harder, and this causes microscopic damage to the muscle fibers, resulting in stiffness or soreness. This type of injury is sometimes referred to as delayed onset muscle soreness (DOMS).

Any movement can cause DOMS, but it is commonly caused by:

• Jogging or running downhill
• Using weights
• Doing squats
• Doing push-ups