My 18-year-old cousin is moving to my area this Summer and I am going to start training with him. He's new to training. Currently he is 5' 6" and 145-pounds at 9-percent bodyfat (measured during a university course that had access to the testing facilities).
Given his leanness and lack of previous training, would you say that he would be able to add a fair amount of lean mass for a relatively extended period of time with consistently solid nutrition and training habits? He has expressed a desire to be serious about this and to do what it takes to have success. I'd like to help him make as much progress as possible without shortchanging himself by being the type who doesn't devote long enough to muscle-growth phases or seems to start cutting way before truly needed.
If he keeps nutrition in check, would he be able to train for size over the course of at least 2 years before needing to trim down at all? I was thinking of setting a cap around 13-percent or so and then having him gain as much as possible while no higher than that cap, cut back down to 10 percent or so, and then repeat the process until he achieves his end goal weight and bodyfat percentage.
His ultimate goal is to retain as much muscle as is within his genetic potential and eventually carry that at around 8-9 percent bodyfat.