The first one of these is An example of how important your sleep positioning can be. In that I cover the similarities between a lateral pelvic tilt and how one sleeps. Next up, the similarities between sleep positioning and a swayback posture.
First up, going over a swayback posture. I’ll use some pictures from Kendall’s book, many of which are found online.
The most pressing aspects of this posture are:
The hips are extended:
The lower back is being pushed forward:
Often to the point it’s in extension:
The thoracic spine may be flexed, and head in forward head posture:
Note how far the head is in front of the shoulders
From the side, we could simply say the body’s center of mass is being pushed forward:
With that, it’s very common for the feet to be turned out and or the knees to be turned in. (This isn’t so much part of being a “swayback” as it is common postural / movement issues.)
And the neck may be tilted,
These are very, very common issues.
–
Connection to sleep positioning
Let’s look at someone sleeping on their stomach:
Right away, there’s some obvious connection. The lower back is extended:
The hips may or may not be extended.
This can depend on the mattress’ hardness. Here’s a good picture from a mattress company:
Specifically looking at stomach sleeping:
Notice in the “Soft” category the hips are extended:
Because the body’s center of mass is located around the hips, this is where the body is most likely to sink into the mattress.
Even if you’re on a hard mattress, negative things can happen at the hips. Because gravity is still acting on the hips, gravity can still push the head of the femoral head downwards:
I’ve written about this hip ailment before here, here, and here. In summary, it’s not a good thing.
A less obvious connection is at the feet. When sleeping on the stomach it’s very likely the feet are going to turn out:
Finally, the neck. It’s typical to favor having the head turned one direction more than the other. I haven’t really examined this, but it seems most people favor turning their head to the left. Even a quick google image search of “Stomach Sleeping” seems to agree:
Of the people on their stomach, notice how many have their head to the left.
This coincides with what you often see at the neck in stance: Tilting to the left.
–
A full comparison
Our two positions:
Outlining:
Rotating:
The other way:
Get off your stomach.
–
You can get my manual on sleep positions here: 
Or find more about it here.
–
Deon Bentley
April 9, 2016
I have a sway back, and my tummy is boating
reddyb
April 10, 2016
nate22
July 21, 2016
what kind of mattress is best for lordosis? Every mattress I’ve had sags in the middle and I think that might be the cause of mine, personally. I grew up on a mattress like this. I bet a firm mattress to the point of being almost the floor is best, but that’s just a guess. For a while I did sleep on a very flat futon and my back actually probably wasn’t any better. But, it’s hard to remember that period as I was a drunken fool just out of college.
reddyb
July 22, 2016
Harder surfaces do tend to work better, but you can be on a hardwood floor and still have the back arch on you. This is when you need to help the legs out with support. I go over this a good deal in the sleep manual- https://b-reddy.org/2012/08/06/sleep-with-less-pain-tonight/