Knee pain and sitting are usually associated with:

  • sitting for long periods of time
  • moving from a sitting position to a standing position
  • knee discomfort that doesn’t go away when seated

This knee pain can be the result of:

  • the length of time you’re sitting
  • the position you’re sitting in
  • the furniture you’re sitting on
  • a health condition that causes knee pain

Keep reading to learn about why sitting can cause knee pain, and how to treat and prevent this kind of knee pain.

When you’re inactive for an extended period, you may experience knee pain. Sitting for a certain length of time can cause your muscles and tendons to stiffen, and this can cause discomfort.

Many people find themselves sitting for a long time at:

  • work
  • events, such as a movie or show
  • meals
  • home watching TV or using a computer

What’s considered a long time to sit?

Harvard Medical School suggests that sitting for more than 6 to 8 hours a day is potentially bad for you.

They suggest that you avoid prolonged sitting, but if you must be seated for long periods, move around and stretch every 30 to 60 minutes.

Sitting in a wrong or awkward position, such as with your legs crossed or bent underneath you, can put pressure on your kneecaps and result in discomfort.

If you know you’re going to be sitting for extended periods, learn about and adopt ergonomic positions that won’t put undue pressure on your knees.

The discomfort you feel in your knees when sitting could indicate underlying causes, such as arthritis or patellofemoral pain (PFP).

Arthritis

When you haven’t moved your knees for a while and start to feel stiffness and pain, it might be osteoarthritis, according to Harvard Medical School. Osteoarthritis may also cause knee discomfort when you stand up from a sitting position.

A chronic joint inflammation, osteoarthritis typically affects people over age 50, but it can also appear in younger people. According to the Centers for Disease Control and Prevention (CDC), about 23 percent of American adults have arthritis.

Treatment of osteoarthritis in your knees may include:

  • physical and occupational therapy
  • acetaminophen (Tylenol)
  • nonsteroidal anti-inflammatory drugs, like ibuprofen (Advil, Motrin, Aleve)
  • cortisone injections
  • joint replacement

Patellofemoral pain (PFP)

According to a 2016 study, about 50 percent of people with PFP have problems with prolonged sitting with bent knees. People with PFP, also known as runner’s knee, also commonly experience knee discomfort when squatting and walking up and down stairs.

PFP is associated with:

  • knee joint overuse
  • knee and hip muscle imbalance
  • kneecap injury

Treatment of PFP may include:

  • rehab exercises
  • supportive braces or taping
  • icing after exercise
  • pain medication, like acetaminophen (Tylenol) or ibuprofen (Advil)
  • surgery

The ergonomic design of the chair that you’re sitting in can have an impact on knee pain.

For example, if you sit for long periods of time at the office, your chair should be properly designed and positioned correctly with the other furniture you are using, such as your desk.

If your workspace is not positioned at the correct distance and height, you could be holding yourself in an awkward position that, over time, can result in knee pain.

Knee pain at a workstation is often intensified by the chair being too low or positioned so you keep your knees bent for too long.

Workspace ergonomics: Best practices

According to Mayo Clinic, if you work at a desk or counter, you can take these steps to ease knee and other joint pain:

  • Select an ergonomic chair that properly supports your spinal curves.
  • Set the height of your chair so when your feet are resting flat on the floor, your thighs are parallel to the floor.
  • Consider a footrest if you can’t adjust chair height properly, or if the height of your desk requires you to raise your chair beyond where you can rest your feet flat on the floor.
  • Adjust the chair’s armrests so your arms can comfortably rest on them with your shoulders relaxed.
  • Your desk should allow clearance for your knees, thighs, and feet.
  • If you work at a computer, put the monitor directly in front of you with the top of the screen at eye level (or slightly below). It should be about an arm’s length away when you’re sitting up straight in your chair.
  • Your keyboard should be directly in front of your monitor.

If you have knee pain while sitting, you might also consider a standing desk.

If you have knee pain when sitting, a number of reasons could cause it, including:

  • sitting with your knees bent for too long
  • poor furniture ergonomics
  • arthritis
  • patellofemoral pain

If you must sit for prolonged periods (more than 6 to 8 hours a day), consider getting up to stretch and move every 30 to 60 minutes.