Ok I'm 5'10, 175lbs and 15 y/o. I play middle line backer formy footbal team, and next year am goin into seniors. My coach has set up a cross fit training program for us and expects us all to do it. I want to put on about 10 more pounds by nxt year. I'm afraid if i do the cross fit.. i'll gain lots of stamina but get skinier. Also i don't want to just get really big and not be able to play a lot nxt ear becuz of conditioning.. what should i rather do weight lifting, cross- fit, or a mixture of both?