Where EXACTLY are the sit bones?
09-11-08 | 09:12 AM
#1
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From: Hammerland
Where EXACTLY are the sit bones?
Responses to my thread "Hypothesis: Sit bone span equal to finger span"
(www.bikeforums.net/showthread.php?t=464117 )
indicate a huge variation in not only the width of what riders call their "sit bones" but,apparently, where they are measuring. References to "having us put our hands up our butts" make it sound like some riders are measuring way far back.
Various sources describe how to measure the gap in the ischial tuberosity. However, this bony structure is V-shaped (?) and the portion that is used in riding depends on the individual's position, yes?
In my case, I run a pretty significant saddle-to-bar drop (15 cm.) and am rotated pretty far forward, so most of my weight rests on the small, forward part of the V. Someone in a more upright position would put their weight further back. So, isn't it true that what constitute your true "sit bones" is dependent on the activity we are talking about?
(www.bikeforums.net/showthread.php?t=464117 )
indicate a huge variation in not only the width of what riders call their "sit bones" but,apparently, where they are measuring. References to "having us put our hands up our butts" make it sound like some riders are measuring way far back.
Various sources describe how to measure the gap in the ischial tuberosity. However, this bony structure is V-shaped (?) and the portion that is used in riding depends on the individual's position, yes?
In my case, I run a pretty significant saddle-to-bar drop (15 cm.) and am rotated pretty far forward, so most of my weight rests on the small, forward part of the V. Someone in a more upright position would put their weight further back. So, isn't it true that what constitute your true "sit bones" is dependent on the activity we are talking about?
09-11-08 | 10:37 AM
#2
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From: A Coffin Called Earth. or Toronto, ON
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get measured out by specialized's butt-o-meter...
or just sit in a hunched forward position on carbon-copy paper.
or just sit in a hunched forward position on carbon-copy paper.
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Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
09-11-08 | 11:08 AM
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From: Hammerland
Yeah, yeah. The point is those things are not the part of the pelvis that bears the weight in a typical road-bike position. So what's the point in measuring them********************************************************************************??
It looks (from your diagram0 that the bones that bear most of the weight in road biking are the "inferior pubic ramus".
Inferior Pubic Ramus: new name for Pcad.
.
It looks (from your diagram0 that the bones that bear most of the weight in road biking are the "inferior pubic ramus".
Inferior Pubic Ramus: new name for Pcad.
.
Last edited by CharlieWoo; 09-11-08 at 11:12 AM.
09-11-08 | 12:09 PM
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Find a crappy saddle and ride a century on it. You'll know exactly where your sit bones are by the end 
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09-11-08 | 12:09 PM
#10
I have similar socks...she looks much better in them.
09-11-08 | 12:22 PM
#11
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I agree that for me the sit bones are irrelevant for either my road bike or my touring bike. That is not the part that bears most of the weight when I ride. The whole "sit bone thing" always confused me.
Anytime I bring this up people seem to think I am from Mars. Maybe you and I are just both weird?
Anytime I bring this up people seem to think I am from Mars. Maybe you and I are just both weird?
09-11-08 | 12:31 PM
#12
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From: Hammerland
I agree that for me the sit bones are irrelevant for either my road bike or my touring bike. That is not the part that bears most of the weight when I ride. The whole "sit bone thing" always confused me.
Anytime I bring this up people seem to think I am from Mars. Maybe you and I are just both weird?
Anytime I bring this up people seem to think I am from Mars. Maybe you and I are just both weird?
09-11-08 | 12:35 PM
#13
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Yeah, yeah. The point is those things are not the part of the pelvis that bears the weight in a typical road-bike position. So what's the point in measuring them********************************************************************************??
It looks (from your diagram0 that the bones that bear most of the weight in road biking are the "inferior pubic ramus".
Inferior Pubic Ramus: new name for Pcad.
.
It looks (from your diagram0 that the bones that bear most of the weight in road biking are the "inferior pubic ramus".
Inferior Pubic Ramus: new name for Pcad.
.
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09-11-08 | 12:37 PM
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From: Hammerland
09-11-08 | 02:04 PM
#15
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Bikes: 2006 Giant TCR Comp2, 2003 Giant Iguana, Formerly a 1982(?) Allegro Ninja, now known as "the 'Coon", 1999 Cannondale R600
DrPete is absolutely right. You should be weight bearing predominantly through your ischial tuberosities/sit bones, with some light pressure on your pubic ramus, and slightly more in an aero position. If you are sitting further back, you are sitting on your sacrum or coccyx (which a lot of people do). This can cause injuries from sacrotuberous sprain to muscle straings to nerve root impingement, and so on.
If you're riding further forward, your pelvis is tilted likely more anteriorly or forward, and you are sitting on your perineum, and resting on the ischiopubic rami, and the internal portion of genitalia. NOT a place which was designed to bear weight. This area is surrounded by nerves and arteries.
If I ride that far forward, it just squishes my girl parts... which kust sucks. If you're a man and you're bearing weight in this area, you're also squishing erectile tissue and your urethra.
tata
If you're riding further forward, your pelvis is tilted likely more anteriorly or forward, and you are sitting on your perineum, and resting on the ischiopubic rami, and the internal portion of genitalia. NOT a place which was designed to bear weight. This area is surrounded by nerves and arteries.
If I ride that far forward, it just squishes my girl parts... which kust sucks. If you're a man and you're bearing weight in this area, you're also squishing erectile tissue and your urethra.
tata
09-11-08 | 02:06 PM
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DrPete is absolutely right. You should be weight bearing predominantly through your ischial tuberosities/sit bones, with some light pressure on your pubic ramus, and slightly more in an aero position. If you are sitting further back, you are sitting on your sacrum or coccyx (which a lot of people do). This can cause injuries from sacrotuberous sprain to muscle straings to nerve root impingement, and so on.
If you're riding further forward, your pelvis is tilted likely more anteriorly or forward, and you are sitting on your perineum, and resting on the ischiopubic rami, and the internal portion of genitalia. NOT a place which was designed to bear weight. This area is surrounded by nerves and arteries.
If I ride that far forward, it just squishes my girl parts... which kust sucks. If you're a man and you're bearing weight in this area, you're also squishing erectile tissue and your urethra.
tata
If you're riding further forward, your pelvis is tilted likely more anteriorly or forward, and you are sitting on your perineum, and resting on the ischiopubic rami, and the internal portion of genitalia. NOT a place which was designed to bear weight. This area is surrounded by nerves and arteries.
If I ride that far forward, it just squishes my girl parts... which kust sucks. If you're a man and you're bearing weight in this area, you're also squishing erectile tissue and your urethra.
tata
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09-11-08 | 02:07 PM
#17
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From: Hammerland
DrPete is absolutely right. You should be weight bearing predominantly through your ischial tuberosities/sit bones, with some light pressure on your pubic ramus, and slightly more in an aero position. If you are sitting further back, you are sitting on your sacrum or coccyx (which a lot of people do). This can cause injuries from sacrotuberous sprain to muscle straings to nerve root impingement, and so on.
If you're riding further forward, your pelvis is tilted likely more anteriorly or forward, and you are sitting on your perineum, and resting on the ischiopubic rami, and the internal portion of genitalia. NOT a place which was designed to bear weight. This area is surrounded by nerves and arteries.
If I ride that far forward, it just squishes my girl parts... which kust sucks. If you're a man and you're bearing weight in this area, you're also squishing erectile tissue and your urethra.
tata
If you're riding further forward, your pelvis is tilted likely more anteriorly or forward, and you are sitting on your perineum, and resting on the ischiopubic rami, and the internal portion of genitalia. NOT a place which was designed to bear weight. This area is surrounded by nerves and arteries.
If I ride that far forward, it just squishes my girl parts... which kust sucks. If you're a man and you're bearing weight in this area, you're also squishing erectile tissue and your urethra.
tata
09-11-08 | 02:11 PM
#19
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From: Vancouver, BC
Bikes: 2006 Giant TCR Comp2, 2003 Giant Iguana, Formerly a 1982(?) Allegro Ninja, now known as "the 'Coon", 1999 Cannondale R600
I can't make any guarantees, but if I had to put money one way or the other-- YES. you are going to die... sooner or later.
09-11-08 | 02:14 PM
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From: The West Side (Of Rochester, NY).
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09-11-08 | 02:15 PM
#21
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not yet...but I can't same the same about this line.
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"Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey
09-11-08 | 04:17 PM
#22
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From: La La Land (We love it!)
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I will leave that one to the more "axademic" dudes.
09-11-08 | 05:47 PM
#25
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From: Rocket City, No'ala
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No.
Luckily, there is a solution.
HTFU and pedal harder. That'll put more weight on your feet and less on your sit bones.
I see way too many riders with the saddle too low. This not only means the pedalling is inefficient but also too much weight is being borne by the sit bones.
Luckily, there is a solution.
HTFU and pedal harder. That'll put more weight on your feet and less on your sit bones.
I see way too many riders with the saddle too low. This not only means the pedalling is inefficient but also too much weight is being borne by the sit bones.