3dbiker

What is the purpose of measuring the height of the sternum from the ground?
And what does it mean to have a lower sternum height measurement than the standard one for the person's height?

Iride01 

It probably means something if you are using something that calculates something from that measurement. But if you are using other fit systems that don't use that measurement, then it means nothing.

There are all types of methods devised to fit a person to a bicycle. They don't all use the same measurements. And those that do may not even agree with each other where that puts you or what size of something you need.

Welcome to BF.

KLiNCK

Not trying to be "a goof" but....

That's kinda like asking : How long is a piece of string?

What type / style of bike??

What is the weather like in your area???

Do you ride year round????

How is the bike stored?

There is not ANYWHERE NEAR ENOUGH information for members to try and help you sort YOUR potential issue(s).

oldbobcat

The sternum is the bone in the center of the chest where the ribs and clavicle are joined. As you can see, it is quite long and has three sections.


Some fit systems use height to clavicle as a more accurate form of functional height measurement. I think it's splitting hairs

ThermionicScott 

Hmm, questions I have never thought to ask, and answers I will never care to know.

zandoval 

As I get older the distance from my sternum to the ground when ridding is increasing...

pakossa

Main reason for measuring this in some fit formulas, is to compare it to the length of your inseam, to determine if your torso is shorter or longer than average. If that shows your torso is much shorter or longer than average, then it's likely your reach to the handlebars will likely need to be shorter or longer than average (though flexibility/core strength can also affect the ideal reach).

oldbobcat

If your ape factor is greater than 1, your arms are long. Less than 1, they're short. If your legs are greater than 46 percent of your total height, they're long. Less than 45, they're short. Or something like that.

Kontact 

A fit system may use that measure to make up for things like a long neck, since the distance of the top of your head to your shoulders isn't actually pertinent to bike fitting.

However, the height of your shoulders would be just as important.


These systems that measure everything rarely produce good fit information, because they can't take into account how you bend.

Alan K

Yes, but these measurements are a good beginning. Of course, a person with pronounced kyphosis, will need to be specifically measured for his needs. This is why the best option is to consult a knowledgeable bike professional who has all the right equipment to do the job. Or consult a sports medicine person.

Kontact 

I don't think they are a good beginning. They produce very specific yet erroneous results.

You are better off getting a frame based on your height, setting saddle height via inseam and formula, use KOPS or an average saddle set back, measure the bars to your shoulders and try stems until you find the sweet spot.

That all takes less time then measuring your body, is less prone to measuring errors and the logic of the fit is obvious.

Alan K

Are those not “measurements” or are we talking about eye-balling here?

I have seen people buying used bikes without putting any effort in checking if it will fit them, merely because it seemed cheap. I have also observed an overzealous sales person pushing to sell a floor model to a guy for the the size was obviously too large - commenting that he can easily lower the seat and then it will be just fine! Trying a bicycle based on any useful measurements is better than buying some random bicycle because someone recommended it. But whatever works for you…

Kontact 

They are directly applied measurements used in sequence, not a download of numbers that produce a complete answer without meeting benchmarks along the way.

If those programs didn't often produce such crazy results I would have a different opinion.


But I also think "fitting" in general has created this misunderstanding that bicycle position is incredibly bespoke and difficult. The details are difficult, the basic position is pretty simple.

79pmooney

To the topic, "What is the height of the sternum from the ground?": Surely the maker placed a datum on the sternum in manufacture. Might take autopsies to locate them in general or surgery to find yours. I'm content to just know it's probably there and that it really doesn't matter all that much in my everyday life. (Sorry, couldn't resist.)

I have long limbs and short torso. I've read that I should be riding bikes with short reaches. All the bikes that have really worked for me have exceptionally long reaches, either with a long top tube or long to very long stem, often with deepish or longish reach handlebars. (I favor long brake hoods too set well down on the bend. I am not saying anyone should copy me. I just love to be able to ride as far as I need to comfortably with my back being close to horizontal. I learned many years ago I am not an upwind machine but I still find myself needing to go that from time to time.)

Alan K

With long limbs (legs as well as arms) and short torso, relatively longer reach, all else being equal, makes sense to me.

Kontact 

Looking into this, you aren't measuring to the ridge of bone known as the sternum, you are measuring to the "sternal notch", which is the top of that ridge, between the clavicles and at the base of the throat. That is a definite point.

https://www.clockworkbikes.com/measurements.php

Alan K

The obvious intended purpose of this measurement, to me it seems, is to provide a relatively accurate measure of where one’s arms/shoulders are likely to begin and combined with measurements of arms length, this information can be translated into individual’s reach.

As for human anatomical terms, I’m reasonably sure most people aren’t interested in getting into a pissing contest with you but if there is enough interest in learning about details of human anatomy, I’ll be happy to provide needed information - I’m sure it hasn’t changed in the last 5 decades! 😉

Kontact 

What is it we would be debating about anatomic terms? I was quoting a website that uses the diagram from the OP.

Alan K

Sorry, but it seems that there are some individuals on this forum (not you, I suppose) who engage in meaningless futile exchanges for reasons of their own.
Peace!

Kontact 

Okay... so what was it you had to say about "sternal notches"?

Alan K

You may have to go back and read that post.

Kontact 

Talk about "Meaningless and futile exchanges."

Say what you mean or leave me put of it.

Alan K

It wasn’t about you. It was brought up by someone else. Sorry about the confusion.