Walcott should work mainly on his upper body strength as he is too easily brushed aside still. He has already put on quite a bit of muscle mass, but mainly to his lower body as I can tell.
Flob, I said that it is silliness to suggest that increased muscle mass will impact negatively on speed and acceleration. I stand by that, and you just have to look at pretty much every top sprinter to know that it's true. However, as Klaus points out football sets very different demands on the body than sprinting does. There is obviously a break-off point where the added weight will impact your stamina negatively over 90 minutes, and the added muscle mass may impact your agility negatively. In Walcott's case there is nothing to suggest he couldn't put on quite a bit of muscle mass without it impacting his game negatively. All in my opinion of course.
And yes, I do know quite a bit about this since it has been a part of my education. 🙂
