Mark Rippetoe

At the Iron Horse Pub here in Beautiful Downtown Wichita Falls. Our band, the Anarene Transit Authority, will start at 8:30 on Wednesday night December 17, and play two sets. You are invited if you can make the trip.

Jason Donaldson

Any chance of a recording or a live stream for those of us who cannot make the trip?

Mark Rippetoe

Probably beyond our technical ability.

5pointer

What instrument do you play Rip?

Mark Rippetoe

Trumpet and drums. Not well.

Subby

Back Pain and Back Strength

This article is all I could find from a cursory search, but it references the point that I don't quite understand:

"So here we are, upright with a vertical spine that still wants to be horizontal, with all the problems that come along with it, and a very good reason to solve these problems."

I've seen/heard this quote mentioned many times, whilst the article touches on it a little bit, I don't think I've ever heard or read an explanation on what the problems with the human spine are in a bipedal human, compared to a quadruped human.

What exactly are the mechanical flaws that cause back pain that would not do so if we walked on all fours. I've thought about it and the spine, like all structures in the body has evolved to fulfill multiple tasks: It has to weight-bear the entire organism and provide structure whilst allowing mobility, hence the articulated vertebrae design not a single shaft of bone, it has to provide various attachment points for muscles, it has to allow for ligaments to run alongside to maintain positioning on vertebrae on top of each other, it has to protect the spinal cord as well as providing allowances for nerves to enter/leave the spinal cord. And these have various requirements at differing parts of the body, hence the need for 3 separate types of vertebrae.

The only flaw in the design that I can see is that the intervertebral discs compress over time, there doesn't appear to be a mechanism to maintain the clearance of bone on bone contact between vertebral segments. There's definitely body structures that are designed worse. All in all it's pretty good and I doubt I could design something similar.

Mark I was hoping you could point to where you've already discussed on what the flaws are in an upright spine compared to a horizontal spine, or elaborate on them here please?

Mark Rippetoe

The only flaw in the design that I can see is that the intervertebral discs compress over time, there doesn't appear to be a mechanism to maintain the clearance of bone on bone contact between vertebral segments.

This is the main problem. As the disc degenerates and the intervertebral spacing degrades, the articular faces of the vertebral bodies respond by generating osteophytes in an attempt to re-space the anatomy, causing unpleasant problems for the nerves and associated structures.

Stop thinking of it as a design, and start thinking of it as the accumulated changes that have occurred over millions of years. This just happens to be where we are right now. Which is fine if nobody gets to be 35.