I have mild scoliosis on my upper (thoracic) spine that looks like a C (opening to the right).

I also happen to like crossing my legs. Crossing the legs obviously introduce some asymmetry to the posture, which can be done two ways: left leg over right | right leg over left

I am convinced that one of these will be preferable depending on the kind of scoliosis you have. Is there any literature on this that would help me decide?

  • General health questions unrelated to fitness are off-topic on Fitness.SE. We do have a few other questions on scoliosis but I'm not sure if this one hits the "exercise requirement" enough. I'm going to leave it open for the moment and see what the community thinks but check out the on-topic section.
    – C. Lange
    Sep 23 at 11:57
  • Posture will be person-dependent--I'd just take pictures of both and see if either produces counter-curvature after allowing some settling-in time. For example, I tend to lean towards the side of the leg-on-top, but it depends on the chair. It might matter if no other targeted exercises/stretches are being done. Sep 23 at 12:22
  • Which side felt more comfortable for you?
    – Jun
    Sep 24 at 17:40

First I must say that we do not give medical advice on this SO, I am not a doctor and am not providing advice of any kind. You should consult a doctor for any action you take.

There is a 2016 study where the subjects were instructed to sit on a chair, the height of which was adjustable, so that their knee and hip joints were bent at 90°.

In this study, the right leg-crossed sitting posture led to a decline in the right trunk length with time and, in terms of pelvic torsion, increased the posterior rotation of the right pelvis when compared with the left pelvis. In terms of the state of the spinal alignment, this posture generated concavity on the right side and convexity on the left side. In addition, it was analyzed that spinal deformities were caused by the posterior rotation of the right pelvis.


In individuals with a limited range of hip joint motion, this will increase the pelvic rotation. Therefore, the findings of this study suggest that crossing a leg while sitting can cause scoliosis and spinal deformities.

It referenced a 2005 study:

One previous study that had 20 healthy adult men perform a one-leg-crossed sitting posture reported statistically significant differences in the muscle activity of the musculus rectus abdominis, internal oblique, and external oblique muscles after the intervention. This resulted from the one-leg-crossed posture, causing asymmetry of the trunk muscles.

And another 1975 study:

In most cases, however, people cross a leg while sitting because this posture feels comfortable or has become a habit. This causes left-right asymmetry in the body and increases the rotation of the lumbar spine by rotating the pelvis, following the bending of the hip joint

And take note of the limitations they give at the end:

This study has some limitations regarding the generalization of its results. First, it did not observe the subjects in the one-leg-crossed sitting posture for long hours, and it involved a relatively small number of subjects. Second, it could not identify the effects of the one-leg-crossed sitting posture on trunk stabilizers. Therefore, future studies should be conducted to identify the correlation between unstable postures commonly adopted in daily life and musculoskeletal diseases.

It seems there are effects on your spine from crossing your legs while you sit, enough to potentially cause both scoliosis and asymmetry in your trunk muscles. Favoring one side could end up in more harm than good by messing up your scoliosis even worse, or it could potentially help. Again, what you should take away from this is that you should ask a doctor and evaluate from there.

  • My whole family are doctors, and none of them know a physical therapist capable of answering this question with confidence. I might actually get myself scanned in both postures and see wha the impact is. now im just intellectually curious. Sep 23 at 7:55
  • It should be noted that these studies were merely assessments of postures that were seen during crossed-leg sitting. They provide absolutely no evidence that such sitting will have any effect on the body that will persist after you stand up, and the conclusions of the 2016 study (that such sitting could cause scoliosis and spinal deformities) are, frankly, insane. Sep 23 at 11:34
  • @DavidScarlett After looking into this a bit more, you are correct that there doesn't seem to be concrete evidence that favoring one side while sitting cross legged can cause scoliosis. Something to keep in mind is that 85% are idiopathic. Naturally there will be a lot of theories that people are trying to prove, but trying to set up long term studies for something that only affects 2-3% of the population where the majority of people only experience mild symptoms can be difficult. There still does seem to be a lot of interest in the idea that muscle imbalances can cause scoliosis though. Sep 23 at 17:13

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