Morphology and physiology are individual which is why emulating other's positions isn't an efficient way to get aero.
Essentially Tom can put out lots of power in the above (likely quite aero) position and you can't, so find another position.

He's also very tall and limited by the UCI rules for reach. He's obviously adapted pretty damn well to it but his position may look different if he was a triathlete.

Yup. He'd be able to put a decent dent in his CdA if he was allowed to stretch.

Understood, but...the last sentence of my post is saying I understand that while I might not be able to learn the position (every body is different, same as you're saying), I still want to understand the position for my own edification. Learning why, how and what is important in learning about body positioning, testing, making improvement and correction (if/when a change creates problems in testing), adapting ultimately to what works for each person's body and abilities. Not everyone has access to a physiology lab and wind tunnel, so studying high performing examples, experimenting, monitoring power, HR, pace, comfort factors, and tuning position based on what works best for each person seems a sensible way to go.

In previous sports, I learned from others who were much more experienced than I was, experimented with what I learned about form, technique and position, adapted to what worked for me specifically and the results were very helpful. It didn't mean I would try to force adoption of someone else's form or position exactly, it meant there were incremental important elements learned which ultimately contributed to optimizing. Everyone can learn from high performing examples, and adapt and tune to what works for the individual. Further, as a previous coach in other sports, I took it upon myself to analyze body mechanics and share with athletes so they could understand these concepts along with technique, so they could always be learning and understanding from others and from their own experimentation, always learning, always growing as a student of their sport.

I'd be willing to bet that he doesn't need any special techniques to achieve his position, he just does it. When you test a lot you get to know what will and won't work pretty quickly.

Why do you think he is engaging his core to shape the lower back? It isn't an unusual posture. His lower back is where most of the bend occurs rather than pivoting at the hips. It tends to make the hip-thigh angle less acute at the top of the stroke.

As someone mentioned, UCI rules penalize anyone who isn't short. Stretching out isn't an option, even if it would be faster.

Not that I'm the same caliber as Dumoulin, but you can see my photo in the other thread and note that my hips don't rotate forward either. I don't intend to do this, it just happens. I've never felt like it restricted my breathing or my power. Tony Martin is another who has a very curved back in his TT position.

---

Coach at TriForce Triathlon Team: https://www.triforceteam.com

That's right, no way to know if he engages the core. I was interpreting what I saw, and correlating that to what I'd heard about that type of lower back/ab position, but it's bad on my part to assume (everyone is different). I thought there might be some method behind it.

Holy deja vu Barman!

(just came here straight after timetriallingforum..!)

I can copy and paste too. :D

Looks to me that he's rotating his hips back to open angle instead of forward, which is what's causing the lower back shape.

Different community, different experiences and things to learn sometimes.

I don't know. After reading for years about the horrors of UCI rules, I was preparing for the worst when I had to get my TT bike UCI legal for a race. I'm 6'4" and have what I consider a moderately stretched position. I was surprised that it was no big deal at all. I did have to take the morphological exemption at the bars to avoid having to make any changes, but I didn't even need the entire exemption.

That said, 6'4" is kind of a sweet spot. It's guys just under 190cm who would like have the biggest problem (other than guys waaaay over 190cm).

I'm 6'0", don't have a long torso or arms. My normal saddle is 8cm behind the BB, and the end of my shifters are 83cm in front of the BB (3cm illegal). 14cm saddle to pad drop. And I'm not close to the 120deg angle they use to disqualify people for superman reach. Tall riders can meet the rules, and maybe you like that position, but the rules are very restrictive for tall riders who'd like to stretch out a bit.

BTW, didn't they previously measure to the shifter pivot? When did they change to the end of the shifter?

A) Seats too high
B) Needs shorter cranks

Jk

- They don't measure the 120° any longer (you technically don't have to be present with your bike nowadays)
- I believe it was the 2012 revision (or thereabouts) that they changed it. The idea was that some people were throwing on longer shift levers (like old downtube levers) to cheat the system. David Millar for example. (also the hacked "Cobb Aero Brake" and bodged together top mounted Mistral bars is an interesting part of that photo.)

---

My Blog - http://leegoocrap.blogspot.com

I'm 188m. If I were another 2cm taller, I'd get an extra 5cm to play with... But my saddle is at -5cm from the BB and the shifters 88cm in front of the saddle, so even with the exemption I'm out of luck. Ah well, who needs UCI-legal TTing anyway?

---

ZONE3 - We Last Longer

You're in good company...most of the best pro male TT'ers in history posteriorly rotate their pelvis.

---

Jim Manton / ERO Sports

Whether you need the extension depends on the geometry of your body as much as it does your height. You probably have long legs and a short torso, so you don't need it. I'm 6'0" (so just under 185cm) with a long torso and 6'6" arms. People like me get screwed.