Sitting on the knees is a sitting style where your knees are bent and your legs are folded under you. The soles of your feet are faced upward, with your buttocks on top.

The sitting position is used by many people, including children at school or playtime. It’s also practiced in some cultures, like the “seiza” position, a traditional sitting posture in Japan.

Although sitting on the knees is common, it may have negative health effects if you do it often. This is especially likely if you already have existing knee conditions.

In general, it’s not harmful to occasionally sit on your knees. But if you sit in this position frequently, it may cause some health problems.

Sitting with your legs folded underneath can:

  • Add stress on your knees. Deeply bending your knees can irritate the cartilage in your kneecaps. This is especially likely if you’re sitting on a hard surface.
  • Put stress on your ankles. The weight of your upper body also places pressure on your ankle joints.
  • Decrease blood circulation. The load of your upper body compresses your lower legs, which blocks blood circulation. The muscles in your lower legs won’t be able to get enough oxygen.
  • Worsen existing joint problems. If you have knee or ankle issues, sitting on your knees could worsen your symptoms.

If you’re unable to sit on your knees, it may be due to several possible reasons, including:

Muscle tightness

Your hip flexors (front of hips) and quadriceps muscles (front of thighs) stabilize your knee joint. They also work to extend your leg.

However, if these muscles are too tight, your leg can overextend. This reduces your knee’s ability to bend, causing pressure in your knees when your sit on your legs. As a result, you may have knee pain and discomfort.

Patellofemoral syndrome

Patellofemoral syndrome is when you have pain in the patella or kneecap. It may be caused by:

  • overuse
  • misalignment of your legs
  • muscular imbalances
  • weak quadriceps muscles

These conditions cause pain by irritating the tendons and ligaments attached to your kneecap, as well as the cartilage underneath. Sitting with your legs folded under can cause even more irritation.

Osteoarthritis

Osteoarthritis, or chronic joint inflammation, is another cause of knee pain. You’re more likely to develop osteoarthritis if you frequently kneel or bend your knees.

If you have osteoarthritis, your joints may feel:

  • stiff
  • swollen
  • painful

These symptoms can affect any joint, but they often affect the knees. You may also experience knee symptoms if you have osteoarthritis in the ankles.

Knee bursitis

A bursa is a fluid-filled sac that acts as a cushion between tissues. There are more than 150 bursae in your body, including several in your knee.

If a knee bursa becomes inflamed, it’s called knee bursitis. This causes:

  • pain
  • swelling
  • tenderness

Often, knee bursitis is due to frequent kneeling on hard surfaces. This adds friction on the bursa, resulting in inflammation and pain.

Patellar tendonitis

Patellar tendonitis is inflammation of the tendon that attaches your kneecap and shinbone. It causes knee pain during daily movements like kneeling or walking up the stairs.

The condition is commonly due to overuse. Tight hamstrings and quadriceps can also increase your risk.

Quadriceps tendonitis

Similarly, the tendon that attaches your kneecap and thigh muscles can become inflamed. This condition is called quadriceps tendonitis and is also caused by overuse.

If you have quadriceps tendonitis, you may experience knee pain after sitting on your legs.

Instead of sitting of your knees, consider the following postures. These positions are easier on the knees.

But regardless of how you sit, try to maintain a neutral spine. It’s also important to change positions frequently, which will help minimize knee pain and posture problems.

The following sitting positions are better for knees:

With legs crossed

If you need to sit on the floor, crossing your legs can reduce the pressure on your knees. You can also take the weight off your hips by placing them on a folded towel.

With knees bent and feet on the ground

This position is also less stressful for your knees and ankles.

Keep your legs wider than hip-width apart, which will stabilize your body and prevent your back from hunching over.

With knees bent to the side

While you’re in the above position, rotate your legs to one side and place your knees on the floor. Aim to keep both hips on the floor. This will help you maintain a neutral spine.

With legs straight ahead

You can also reduce pressure on your knees by extending your legs in front of you.

Again, placing on your hips on a folded towel can help reduce pressure on your hips.

Seiza is a traditional sitting position widely used in Japanese culture. It’s considered proper etiquette during cultural activities, such as flower arrangement and Judo, a type of martial art. Seiza is also used in daily activities like eating.

In seiza, your knees are bent and your legs are folded underneath your body. The tops of your feet are on the floor. Customarily, men place their knees slightly apart and women place their knees together.

Sitting on your knees won’t cause a medical emergency. But if you frequently sit in this position, it can strain your knees and ankles. The posture also reduces blood circulation in your lower limbs.

If you must sit on your knees, change positions regularly and keep your spine neutral and relax your shoulders. This will protect your joints and posture.