Jason,
In your recent article in Triathlete, about aerodynamics and positioning, you mention** ‘sternum’ angle**. specifically you said that it was best between 5 and 15 deg (if I recall). How are you measuring this angle?
Also, it appears that you have Bjorn with much drop than he has had in the past. Is this correct?
Jason,
In your recent article in Triathlete, about aerodynamics and positioning, you mention** ‘sternum’ angle**. specifically you said that it was best between 5 and 15 deg (if I recall). How are you measuring this angle?
Also, it appears that you have Bjorn with much drop than he has had in the past. Is this correct?
just saw that article in triathlete and he does not look very aerodymnac or comfy in that position. he is looking very stretched out maybe he is very flexible and this is not bothering him though?
just saw that article in triathlete and he does not look very aerodymnac or comfy in that position. he is looking very stretched out maybe he is very flexible and this is not bothering him though?
Comfy I don’t know, but to me he, the layman, looks very aerodynamic.
You’d be suprised how uncomfortable some positions look, yet they are actually pretty comfortable. People always tell me my position is brutal, and must hurt to ride but i have no problems with it.
Grant
Can someone scan a post the picture?
Grant
I know what a goniometer is. I don’t know what angle is being measured here–the tilt of the sternum (this would then be different with people with pectus carinatum compareed to pectus excavatum and those in between, even with the same position of the torso), the angle of the vector of the hip to sternoclavilcular joint as it relates to the horizontal…other???
I did not know what it was until I looked it up and figured other people might not either. (Although I can guess it’s a standard tool for fitters).
Anyway, with the clarification of your question, I guess it’s easier for Jason to answer it.
We have a special goniometer that measures sternum angle that is made by HED. it looks like T square that has angle adjustability. Ill take photos when i get home from the weekend.
Bjorn also has a lot less drop than he has had in the past. the position is very comfortable for him, and considerably more aerodynamic than what he went into the tunnel with (which was a slowly over the years refined position of his super low position).
The entire take away from the article is three fold.
(1) what people “think” is aero isnt always the most aero and best position
(2) frontal profile is more important than what your side profile looks like (three photos below A,B and C are examples of good narrow fast positions, photo D is a good example of a not so good and wide position) Notice how narrow they are and how low their heads are, then compare that to picture D, how wide he is and high his head is.
A 
B 
C
(3) and this one is the MOST important, the best time trialers and triathletes in the world all work very hard to make the unnatural natural. Almost everyone who attempts to set up their position differently than what they usually ride will come back after the first few rides uncomfortable. Be patient as it takes time to first train using these techniques and learning to pedal, steer, corner, drink and feed while being comfortable and powerful using these techniques. When it does become tolerable and eventually comfortable, the results will be in faster bike splits at significantly less efforts.
Bjorn’s new position is actually very comfortable for him.
Bjorn has been training with the new position specifically over the past month as well to make it more effecient. It is also considerably more aerodynamic than what he went into the tunnel with (which was a slowly over the years refined position of his super low position). The numbers (both in the lab, wind tunnel and field testing) do not lie and it is very impressive.
Before
After
Here are some old pics of a workshop I did with HED and QR in which Steve first discussed and taught me the measuring of the sternum for positioning. You can see the special tool in some of the pics.
Before
After
Interesting changes in Bjorn.
I agree with you regarding the time that a TTist has to invest to make the “unnatural natural”. It is a slow process, and I guess it helps if you are still growing when you go through that process .
That was one very important change in Bjorn’s seat height. Looking at the seat post of what it is apparently the same bike, the difference is at least 20 mm - maybe more. The change is also evident looking at his foot.
I wish the best to Bjorn in 2009.
Sergio
Seat height is actually the same. The top “before” pic is a 54cm P3c and the bottom “after” pic is a 56cm P3c.
Seat height is actually the same. The top “before” pic is a 54cm P3c and the bottom “after” pic is a 56cm P3c.
That explains perfectly the more exposed seat post, but still it does seems like there is a difference in height from the two photos. Maybe it is the angle of the photo.
Best wishes,
Sergio
After
Hehe…I recognize that arm angle 
Interesting…
After
Hehe…I recognize that arm angle Interesting…
Perhaps the only difference is that he won’t have to discuss anything with a UCI commissaire before or at the end of the race
Sergio
Perhaps the only difference is that he won’t have to discuss anything with a UCI commissaire before or at the end of the race
Sergio
Seeing as how I don’t see myself doing any races in the near future that require UCI compliance for my position…neither will I 
Besides, I’m not using those bars anymore…and I haven’t tested out yet what “arm angle” is best for me now
.
(2) frontal profile is more important than what your side profile looks like (three photos below A,B and C are examples of good narrow fast positions, photo D is a good example of a not so good and wide position) Notice how narrow they are and how low their heads are, then compare that to picture D, how wide he is and high his head is.
what do you know that these guys don’t? It seems that the Brits have fairly wide arms.
http://i40.tinypic.com/vzyq9i.jpg
http://i44.tinypic.com/2uh4aox.jpg
http://i41.tinypic.com/avsxog.jpg
Thanks very much, Jason. I liked the article, and found it very informative.
BTW, does that sternal angle device, just press against the sternum and measure the angle compared to the vertical (actually, horizontal)? Tha’s what it appears from the frontal views. I have Scheuermann’s kyphosis, which makes me have a pretty significant sternal protrusion, at any position. (This ain’t so great for swimming either, as you can imagine.) So, I guess that if I keep the angle to the horizontal 15deg or less, it probably is acceptable.???
"does that sternal angle device, just press against the sternum and measure the angle compared to the vertical (actually, horizontal)? "
Exactly.
Also, with your Scheuermann’s kyphosis, you actually have a benefit over people that have to “artificially” curve their back. HED has found in the wind tunnel that people with a natural curve in their back tend to have smooth airflow over their aero helmet as it integrates into their back and aero tuck lowering their drag. Saul Raisin has Scheuermann’s kyphosis as well. We call his curvature his “speed hump”.