a big test, you probably have had muscle knots before.

These knots -- otherwise known as myofascial trigger points -- are pretty much what they

sound like: painful spots in your muscles.

They're different from the kind of muscle soreness that shows up a day or two after

you exercise.

But biologists still aren't entirely sure what these trigger points are -- or how to

fix them.

On the one hand, the physical sensation of a muscle knot seems to be real and measurable,

and it's sometimes linked to severe, ongoing pain.

The evidence for this comes mostly from magnetic resonance elastography imaging, a form of

MRI that allows researchers to examine soft tissues -- like muscles.

The images sometimes show V-shaped patterns in muscles that correspond to the little nodules

you can feel at the trigger points.

So it's possible that they come from overactive nerves, which send too much of the chemical

signal that causes muscles to contract -- which shows up as those patterns on scans.

Those extra tense muscles would prevent normal blood flow through the muscle tissue, which

would explain why they hurt.

If that's the case, treatments like massage, physical therapy, and anesthetics might help

by relaxing the tissue, restoring normal blood flow, and reducing pain.

But some studies have shown that they don't help, which could mean that our understanding

is flawed.

For example, in most patients, when researchers injected trigger points with meds that should've

stopped the muscles from over-contracting, it didn't affect pain levels.

And in some studies, many of the other recommended treatments barely helped more than a placebo.

It's just hard to know for sure, because these muscle knots aren't well understood.

The diagnostic criteria aren't clear, which means that studies aren't all that consistent

-- what one group of researchers considers a muscle knot might not count for a second

group.

So it's hard to compare results.

But there is at least one thing that scientists can agree on: understanding these trigger

points is probably important for understanding chronic pain disorders, like fibromyalgia,

or chronic, widespread muscle pain.

Because in order to properly treat pain, especially chronic pain, doctors need to figure out what's

actually causing it.

And maybe, along the way, they will learn more about where those hard, uncomfortable

knots come from -- and how to get rid of them.

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