Many people make this mistake, they jump into heavy bicep work forgetting that their lower arms and wrist are nowhere near ready for it. Remember, heavy bicep curls can be just as dangerous as heavy bench
press's when your wrists can't support the weight, go too heavy and you'll break your wrists...it's true, it happens. Build up to the heavy weight slowly and do some wrist exercises and forearms exercises. A good one is, take a bucket of wet sand, put your hand deep down in it, and open and close your fingers into a fist shape and back out....the resistence of the sand does wonders for you, believe me.