This is one of the hardest bad habits to break, and perhaps never is a bit strong, but the less time you can spend sat with your legs crossed, the better.
There are lots of reasons why you shouldn’t cross your legs, and not all of them are to do with your joints.
Did you know, for instance, that crossing your legs places a direct pressure on the veins that allow blood to return from your legs to your heart? And that this pressure can impede the flow of blood through these veins, increasing the chances of deep venous thrombosis (DVT).
Placing pressure on veins in this way may also cause degradation of the valves within. If these valves are damaged it can predispose to varicose veins.
Interestingly, nearly twice as many people cross right leg over left than the other way around. And there are multiple ways to cross your legs; at the ankles, knee over knee, or ankle over knee. The effect of each is slightly different.
If you are to do one, this chiropractor's opinion is that ankles over ankles is the least problematic. It can be argued that this position can cause over-extension of the leg on top, which over time may stretch the cruciate ligaments of the knee and slightly speed up the wear and tear process, but that's about as bad as it gets.
As well as the potential vascular problems outlined above, crossing knee over knee shortens the muscles around the hip of the leg on top. Unequal muscle length around your hips can cause a wide variety of knock on effects on the mechanics of your hips, pelvis and spine and is a significant cause of back pain.
This position also causes rotation of one side of the pelvis, which is a causative factor in sacroiliac joint problems. Since sacroiliac joints are one of the most common origins of back pain, avoiding sitting in a position that causes strain on them sounds like a good idea!
Finally, crossing your ankle from one leg over the knee of the other, while not putting much pressure on any vascular structures, places a shear stress across the top knee. This stretches the medial collateral ligaments of the knee, which significantly predisposes to osteoarthritis of the knee.
Sitting in this position also strains a ring of cartilage that holds together the hip joint of the top leg. This ring of cartilage is called a labrum, and if it is repetitively strained it can tear. Labral tears can cause pain, catching, clicking and lead to more wear and tear.
So if crossing our legs is so bad for us, why does it feel so comfortable?
Obviously there are social reasons – that is to say crossing our legs may just be habit and something we are used to.
But one factor that isn’t talked about enough is hip flexor length. Hip flexors are muscles at the front of the hip which shorten to lift the leg in front.
Unfortunately, being sat for extended periods of time causes these muscles to shorten more than we would like. Most of us have some degree of hip flexor tightness.
This pulls our pelvis forward and places strain on the lower back, which is made better by bending our hips more. So sitting down, we can make ourselves more comfortable by lifting a leg, and the best way to do this is to place one on top of the other.
So if you find yourself always wanting to cross your legs, try this stretch for 30 seconds, three times per day. After 2-3 weeks you should find the habit is nearly broken.
Hip Flexor Stretch.