2 Reasons the Back of Your Knees Are So Tight, and the Stretches That'll Help

In cases of persistent tightness behind the knees, the blame often falls on one of two culprits: the muscles that flex the knee or the joint itself.

If you're like me — who's been working from the couch for months now — you're probably experiencing muscle tightness in your hamstrings (which connects to the knee joint!) after sitting for long periods.

"When sitting, the lower portion of the [hamstring] muscles that cross the knee is shortened. The muscle gets used to this position and feels tight when you stand up." Alicia Filley, PT, MS, and the founder of The Healthy Hiker, says.

Flex your ankle and straighten your knees for a moment. Are you feeling any tightness in your calves? If so, Filley notes that this is sign of a tight gastrocnemius (a muscle that crosses the back of your knee), too.

If that explanation doesn't resonate with you, knee-joint swelling is the suspect behind door number two.

Right below the muscles in your knee is a thick layer of fascia that covers and protects the back of your joint — and according to Filley, it can be pretty unforgiving.

"When you sit for a while, the joint fluid can't move around as well and may start to accumulate at the back of the knee. This will also give you a tight feeling when you stand up," she adds.

Occasionally the fascia weakens and the joint fluid leaks, forming what Filley calls a Baker's cyst — she says you can sometimes feel it when the knee is flexed, but generally, it just adds to your tightness.

Honestly, I can only handle so much of this fluid talk, so let's get to the promising news: this two-fold problem has a two-fold solution.

"The best way to relieve tightness behind the knee is through frequent movement," Filley says.

Per her instructions, extend your legs under your desk and flex your ankles back and forth every 30 minutes. Every hour, get up and walk around for a few minutes, or switch to a standing desk.

You can thank Filley later for the boost in circulation that gets the joint fluid flowing.

Those breaks are a great time to perform Filley's curated stretches for muscle tightness, too — with your doctor's permission, of course! She recommends adding them to your self-care routine several times a week to feel good.