Right now, I'm pretty good all around on the PRT.  However, I can never seem to get as many push-ups as I want.  I'm tall and lean, more built for running, and so the running is always easy for me.  However, I can't ever seem to max out the push-ups on the PRT.  I try to work on my push-ups daily, but I can't seem to increase my max.  Does anybody have any suggestions on what I should be doing better?  I've tried just maxing out time after time, pyramids, and just lots of sets of smaller numbers, but because I'm so lean, I can't seem to put on much more muscle mass or boost my numbers significantly.  Thanks for any help.