Well, no matter if you are training for size or strenght, your intensity needs to be as high as you can get it, and higher every session if possible. As far as calories required, I think generally eating to
gain muscle or eating to
gain strength is probably close to the same (although I'm not sure, but it would make sense). In both cases, you want your body to be supplied with just the right calories , optimally, this would be whatever your body burned for the day, plus maybe 100-200 more.
This is why it's not very efficient to put muscle on and get rid of fat. I think some people try to cut their calories on cardio days and on weightlifting days, eat so you do'nt have a deficit, but aren't adding much fat...excess of about 200 calories.
