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elk
09-20-2007, 11:35 PM
How long are the ischial tubers, fore to aft?

I wonder if I'm actually sitting on the sit knobs or could I be sitting on my femurs? I can rock back and feel the definate knobs, but I can also rock forward a little and still sit on bones (not pubic bone)..

puzzled.

KnottedYet
09-21-2007, 05:17 AM
The rami connect the ish tubs to the pubes (the whole half of the pelvis is actually all one bone by the time you are an adult, so the names are more like for regions than separate bones).

So, yup, you can be sitting on the rami. Probably not a really good idea to make a habit of it, but everyone rolls around on the ish tub neighborhood when scootching on the saddle or shifting to change power output and such.

You can also be sitting on the femurs if you push your hips back so they aren't on the saddle (but you'd probably have to put your thighs close to eachother such that you can't pedal well) I've done that to rest my poor lil' butt when I've been on a bad-fitting-for-me saddle.

elk
09-21-2007, 08:27 AM
So it's ligament then?
I'm trying to adjust the Brooks B67....if I am finding it easy to sit on the rami then would you suggest sliding the saddle forward a bit? I'm at the far end of the rails ... can only go forward.

I'm OK, but getting wrist pain..

thanks Knotty

Torrilin
09-21-2007, 05:17 PM
Nope, it's a bone. Ligaments are flexible.

Basically, your pelvis is made up of a bunch of smaller bones that grew together. So there's bits that poke out, and bits with weird shapes, and doctors give them names so they can talk about something besides "that pointy bit". Most of those bits were separate bones when you were a baby, and are all part of the pelvis now. The default advice is you "should" be sitting on your sit bones. But we've all got different bodies. If your butt is happy on some other bit of the pelvis, it is probably not wise to adjust things just to sit on your sit bones.

Wrist pain can come from a lot of different sources, so there's no one size fits all answer. For the new and interesting pain that kicks in for me on some 20 mile rides, the right solution is going to involve bar ends or different handlebars. The flat handlebar on my bike doesn't let me have a neutral wrist. My hands *really* don't like that, and will screech at me if I am foolish enough to knit with bent wrists, spin with bent wrists, type with bent wrists... So it's no shock that biking with bent wrists is bad too. I had some hand and wrist pain while I was getting my saddle situated early on... and that got fixed by a better saddle for me, and pushing my saddle further *back*. Bodies are *weird*.

KnottedYet
09-21-2007, 07:34 PM
Oops, yeah, sorry! Rami are boney bits!

Ish tubs are gigantic critters, and you can be sitting all kinds of ways on them. They blend into the rami. (they really are one piece) If you are on the rami themselves, just make sure you aren't hurting the soft tissue between the rami and the saddle. (it's not as tough as the stuff closer to the ish tubs).

I need to find a good skeleton picture... <knot goes off to google>

Edit: Ok, here's a fairly decent pic http://en.wikipedia.org/wiki/Image:Gray241.png Mind you, this is a male pelvis. Female pelvises tend to have more vague ishial tuberosity-becoming-rami zones. (our tubs are bigger, if ya wanna look at it that way!)

See the bits at the bottom that look like donuts with their front edges glued together?

The ish tubs are the bottom halves or so of those donuts. Nice and thick and good for sitting on. And kind of round, so you can roll a good bit on them fore and aft and still be ON them, like rocking chair rockers. (I sit fairly square on my ish tub rockers, you may naturally sit more toward the front of your rockers.)

The rami are the donut-bits that are closer to where the two donuts stick together (pubic symphysis). In the Gray's Anatomy picture the rami are kind of where the words "pubic arch" are printed. You can feel the rami to either side of your labia. (feel upward from the ish tub and follow the bone all the way up to the pubic bone) The skin over the rami area is thinner and soft tissues in that neighborhood are generally a lot more tender. :eek:
If it is truly the *rami* you are weightbearing on all the time, monitor your comfort level. If you feel ok, don't worry. The pic I posted is a male pelvis, the woman's has more wiggle room in the ish tub zone. Your donuts might be more ish tub-y farther forward into what might be more rami-y for someone else.

If it don't hurt, don't worry too much.

boy in a kilt
09-21-2007, 07:36 PM
I'm not even sure I have one of those.

KnottedYet
09-21-2007, 07:39 PM
Mr. KiltTiger! GIR!!!!!!!!!!!

I have a Doom Song t-shirt.

GIR is my co-pilot. :D

boy in a kilt
09-21-2007, 07:39 PM
Now I'm going to sing the Doom Song.

Doom Doom Doom Doom...

elk
09-21-2007, 08:25 PM
Actually, because i am a "fuss er" I moved the seat forward a bit on the rails
and that feels better; also puts me more squarely on the isch.

And yes I think the straight handlebars are bugging me.

I want to sit up a little straighter, or at least have more choice to either lean forward or back...maybe I should put cruiser or moustache handlebars on...

Torrilin
09-22-2007, 04:02 AM
I can lean forward on mine pretty easily. Just do a push up! I can get some sit up straighter by shifting to light contact with the bar. And on 20 mile rides where I do that, my wrists don't complain. Problems kick in when I'm nervous about navigating, or I'm nervous about the terrain.

Probably what I should do is go test ride some other bikes with different bars to get a clearer idea of what works for me.

ChickWithBrains
09-23-2007, 10:05 AM
Definitely NOT sitting on your femurs. It's just not an anatomic possibility unless you have congenital deformities resulting in trochanters that are wildly torsed. Or a really, really interesting seat (or riding position)!

Sounds like you could use a good bike fit. Consider having a pro help you out at your local bike shop or search online for some good pointers on how to fit yourself -- you'll need a friend, a measureing tape (or device to accurately hang a plumb line) to both make sure your seat position positions your knee correctly over your pedal and ball of your foot as well as creating the right angle at the top and bottom of your pedal stroke (i.e., the fore/aft position of your seat and its height). Unfortunately, if you're at the end of the rails and struggle with fit, you might have the wrong frame size -- as I did!

elk
09-23-2007, 02:15 PM
I think I got it figured out...I have spent the last 2 days in relentless pursuit of fit info....and by george...i'm Ok!!!
thank you.

e