why putting a pillow under your knees when you sleep helps with back pain


why putting a pillow under your knees when you sleep helps with back pain

In: 11

Sometimes one of the causes of back pain is tight muscles in the legs. If your muscles are tight and you lay your legs straight, it pulls on your hips, which in turn pulls on your back. By elevating the knees, it eases the tension on the system overall, reducing strain in the back.

When you lift your knees up, you are stretching your lower back muscles.

Keeping your lower back muscles stretched for a long period of time can help relieve back pain due to tight muscles/pinched nerves

Massage therapist here, and side sleeper.

Under knees when supine (laying on the spine) shortens any muscles pulling on the pelvic girdle and allows tight lower back muscles to lengthen.

For side lying, a pillow raising the upper knee will ease the hip flexors, glutes, and sciatic nerve entrapment sites.

Ease means less pain.

It depends on the person and what’s causing their back pain.

Normally when you’re lying on your back, your pelvis is tilted such that your lumbar spine is curved more as if you’re bending backwards (*anterior* tilt causing increased lordosis). If you have pain coming from a pinched nerve or arthritis in the joints at the back of the spine, the increase in curve is going to put more pressure on those further-back structures and cause pain. When you put a pillow under your knees, you’re shifting the tilt of the pelvis toward more *posterior* tilt, which decreases lordosis and puts less pressure on those further-back structures, and should feel more like when you bend forwards.


I know this is isn’t r/Askdocs, but If this is the case for you, you’d probably benefit from practicing posterior pelvic tilts, glute strengthening exercises, and hip flexor stretching.

At a high level, back pain is the result of nerves sending signals to your brain. Either the nerves are broken and sending wrong signals or something is actually “wrong” and your body is trying to tell you something is wrong via pain.

Given your description and since you are talking back pain, either your spine has something wrong (less likely) or your back muscles have something wrong (more likely.)

When it comes to muscles, the problem is often that some muscles are too strong and some muscles are too weak. Many muscles tug on other muscles near them when they are flexed and stop tugging as much when they are relaxed. When you move your joints into different positions, the muscles on one side of the bone are given more slack to relax and the muscles on the other side are pulled tighter. If the muscles are pulled tighter by body position, they may tug on other weaker muscles near them, causing pain.

So, sleeping with a pillow under your knees rotates your hip joint forward. That “gives slack” to certain muscles in your legs and “tenses” other muscles. The extra slack is relieving the pulling on your back muscles and reducing pain (possibly).

All this extra writing to say: you could likely permanently fix or reduce back pain by either strengthening your back muscles or certain leg muscles through exercise or lengthening certain muscles via stretching.

However, all this extra explanation also says there are many causes of back pain not just strong muscles bullying weak muscles and a physical therapist or doctor may have many helpful diagnoses and treatments/rehabs/exercises (not chiropractors! Many chiropractors do not have science based medical degrees.)