Bulking Athletes

Hey everyone,
During a bulk, how long do you feel the body has to adapt to the new weight increases each week or month? The reason I am asking is that I have noticed that my endurance has gone down slightly but my explosiveness has increased. I gain roughly a pound a week as well. I play drums and even though this might not be considered athletic by purists, I feel training and nutrition does play a role in speed and endurance (especially in death metal/extreme metal). I posted in another thread (sort of a hi jack) but I wanted to try to get a more thorough opinion/response by some experienced athletes who have gone through a similar transition. Thanks, appreciate any help.