They're also great ways to relieve stress, which can cause muscles to tense up and trigger low back pain.

They might also cause muscles to contract or relax, depending on the dose and the muscle involved.

An electric shock stimulates this system, and causes muscles to contract.

Testosterone causes the deeper voice, bigger muscles, body hair, and other primarily male features.

This can sometimes cause other nearby muscles to compensate, which in turn can create new wrinkles.

He had the progressive nerve disease, which causes tremors and rigid muscles.

This can cause muscle wasting and decreased blood flow, which can lead to more neck pain.

Fibromyalgia is a common condition that causes painful muscles.

This causes tissues to die and muscle to waste away, and the patient loses weight.

It directly causes arterial smooth muscle to contract, leading to vasoconstriction and increased blood pressure.