90/90 inversion for spinal traction?

[wk105]

Rip,

Do you think this would be better than hanging from belts/ab straps in a rack?



Apparently the 90/90 position is supposed to flatten the lumbar curve for greater traction, and there's no pressure on the ankles/knees.

Thanks.

[Mark Rippetoe]

Why would hanging in an abnormal anatomical position be better?

[wk105]

I can't think of a good reason why. The design is supposed to allow for greater separation of the vertebrae, but achieving that at the expense of an anatomically normal lordotic curve doesn't seem wise. In fact, even that slight degree of lumbar flexion can worsen already aggravated backs.

[Mark Rippetoe]

Think about what lumbar flexion does to the geometry of the disc, anterior to posterior. Now consider the application of tension to this distorted geometry. It might not kill you, but this is a less-than-satisfactory attempt to build a better mousetrap.