I rolled out the TT bike for the first time this year. I would like to ride a 12 hour in the summer. I have been working on my position to try and tuck my head in better - so called tirtoising - and shrugging my shoulders to enable this.
This part worked great but it was clear pretty early that my neck wouldn’t hold out. After 3 hours I could barely hold me head up. Clearly I need to dial back my position to be less aggressive.
Are there any exercises or activities which can strengthen the neck specifically for the kind of loading?
These might help but are ones I do for my shoulder/neck from my physio and osteopath.
Isometric Cervical Side Bending
Row with a band keeping shoulders down.
I’d look at postural exercises as well as sitting working at computers, looking down at phones etc all lead to weakness in the neck and shoulders leading to us been more hunched over.
So Prayer Stretch, Posterior capsule Stretch to reduce the tension. As you say the position is properly too aggressive for your level of flexibility and ability to hold the position. Something my bike fitter constantly brings up when talking about getting aero. You can be put in the most aero position but if you can only hold it for a matter of minutes the net result is you loose.