In addition to what is already suggested, try moving your head around a little bit. I lean my head somewhat from side to side and lucking up for a bit and then down for a quick glans at the computer trying not to be in the same position for long. I also focus on being relaxed in the shoulders.
Dan Bigham touched on this recently. He’s kind of known in the UK as the no1 aero geek so there was consternation when he posted his new bike on IG with 15-20mm of (integrated) spacers. His response was along the lines of ‘this is optimal - weird how everyone wants to get slammed but not optimal’.
More generally, as this discussion went down the flexibility/strength line, it’s essentially asking a fundamental bike fit question: do you fit someone for what they have now, or what they could achieve? Clearly, most people aren’t going to do the miles and/or the off the bike work necessary (for most of us with desk jobs) to get into more aggressive positions, but more ‘serious’ riders may well put in that work.
The answer, according to the the bike fitter I use, is that any new bike you buy should fairly easily allow for at least +/- of 10mm adjustment of stack and reach from your ‘starting’ position. For example, he really likes to see you starting with 10-15mm of spacers, and a ‘normal’ stem angle (-6 to -8) and length (90-120mm). And limit cutting steerer tubes for at least 3 months.
Look at all the WT riders with HUGE stacks of spacers under their aerobars…start with Stefan Kung, who is one of the best TT’ers out there.
Kung could “slam” his aerbars and get a lot lower, but it clearly would not be optimal.
Or sometimes you just have to make what you can get work. I can’t get a bike that has race geometry and a tall enough head tube, so always at the limit of what I can achieve regarding handlebar drop. The body adapts.
This year I had to do a 25m time trial I had entered on a road bike, when my TT bike was ill. I did my best to hold a deep aero position with my hands on the hoods and forearms flat, (parallel to the road) all the way through. It was quite difficult and I found I was slightly better with my hands high up inside the drops, my forearms relatively (almost) horizontal and my back even lower. However it was hard work and my forearms, shoulders and neck ached considerable afterwards. That was for one hour eight mins.
The issue was that my forearms were basically holding up the weight of the top of my body. On my TT bike I am resting on my elbows and my forearms are relaxed.
It made me appreciate how much more comfortable my TT bike is (I have done a 12hr TT on that this year) and how much more aero it is (I am around 8-10 mins quicker over 25 miles on it).
Agree that optimal position is always the primary concern. But different factors are coming into play as to how you achieve that position on a TT vs a road bike (the Bigham quote above is referring to a road bike setup).
On TT bikes now you have a lot of flexibility with where your aerobars are positioned relative to the top of the head tube. Having a big gap between aero bars and base bar tests fast in the wind tunnel, therefore the trend (like Kung) is towards riding smaller frames and then elevating the aero bars. Secondary benefit may be having a more aero position on the pursuits. TTers still ride a slammed stem though.
On road bikes the adjustability of the bars is becoming more of a limiter. The trend is towards integrated one-piece bars which means you can’t easily adjust reach. At best you might be able to order integrated bars in different stem sizes, but it’s an expensive thing to be swapping around, and even for sponsored riders availability is likely to be limited, both in terms of the sizes a manufacturer offers and in terms of current supply chains. So in a lot of cases with a road bike, achieving your optimal position means choosing a frame-bar combo primarily based on reach, because stack is more adjustable. I think if you could achieve the same position on 2 different frame sizes, one with a slammed stem and one with spacers, then the slammed option is probably still better. But that may well not be possible with the frame and bar sizes available to you.
Bigham’s bike is a case in point. It’s the new Ribble Ultra SLR, which isn’t going to be delivered to paying customers until at least Q2 next year. They do offer 5 different stem lengths on their integrated bars on their website, but the narrowest bar option only comes with a 140cm stem length which is pretty long. That bar is 33cm wide across the tops, Bigham says he’s running 30cm width hood-to-hood (which is insanely narrow but that’s another conversation!), so I’m guessing he’s running that bar with hoods turned in a bit, unless he’s gone custom. So I suspect his desire to run narrow bars has led to running a long stem, which in turn has driven him to a smaller frame size to achieve the correct reach, which in turn is what has led to him having spacers to achieve the correct stack. Assume handling comes into it as well - with narrow bars you’d want a longer stem to avoid making the steering too twitchy, which is presumably what has informed Ribble’s bar options.
Long story short - Bigham and Kung are both riding their optimal positions, the difference being that Bigham can likely only achieve that position with one frame size and bar choice which necessitates having spacers, whereas Kung could likely achieve that position with at least 2-3 different frame sizes and has actively chosen to go with a smaller frame and more spacers for aero reasons.
Dangerously off topic but I’m pretty sure Dan wasn’t riding the Ribble SLR’s new handlebars during the Tour of Britain - they looked “normal” to me.
All your points above regarding him riding a small bike ring true though.
Are they the prototype wattshop bars that may or may not go into production depending on UCI rule changes?
Finding options for narrow bars is hard. I’m running 38s want to go 36 with narrower on the track but availability isn’t great. A few round ones about but nice aero profile ¯_(ツ)_/¯.