Ah, sone some searching on the web and found this article.Can you provide any reference for this? I'd be interested to know the process as I'd assumed they would be a fibre and epoxy matrix.All day is fine. If you were shooting an all day competition you'd leave it up. The same bow at a flight competition, I'd let it down after 6 arrows. Horses for courses. I have seen a top end foam core limb from a very big manufacturer that's had it's butt take a set. But you'd not know unless you compared it to an unaffected pair.
Compound limbs are not made from fibres, but powder, so are unidirectional. Completely different behaviour.