Isn't that muscle tone, I believe it's high rep low weight for muscle mass
I really wanna gain weight
Get a good 20 to 30 sets in your workout routine, high weight low reps, get to gnc and get some mass building protein shakes, amino acids and fish oil, great supplements! In 4 months I've put on 17 lean pounds! No joke, and ask them boys at gnc for advice, they know what to do.
Get urself anabolic protein. Use heavy weights with low reps. Different days different muscle groups