Quote Originally Posted by suckysucky
If I had to take a guese bro. I would say your forearms are lacking. As i stated before in my earlier posts IMO the key to biceps are forearms. If you do not have strong enough forearms, even though your bicep wants to and can curl more weight your forearms are not allowing it. Therefor, your bicpes are not getting a good workout because its not that heavy for your biceps.
think he's got it here. i know when i do shrugs, my traps are so strong compared to my forearms that unless i use wrist wraps, my forearms fail first. though i feel it in my traps even without the wraps and near the end will still feel as if my traps can't lift it anymore, i can do far more with the wraps, indicating that it actually is my forearms failing and indeed not my traps.

try adding some direct forearm work into your routine and see if it helps.