Jared Padalecki was a skinny kid when he landed a role in Gilmore Girls. Now, at 25, he is the star of his own CW series, Supernatural, and has the body of a leading man. His transformation began after a 4-inch growth spurt, to his currently 6’4�.

“Suddenly I really needed to add muscle mass,” says Jared Padalecki. He packed on 35 pounds of muscle while staying lean.

He credits Scot Mendelson, a two-time world bench-press champion who guides Padalecki through short but intense workouts and encourages him to snack on 600-calorie protein shakes.

Scot Mendelson does not play around and goes old school on guys like Padalecki: Get strong to get big. “The heavier weights you use, the more muscle fibers you’ll activate, leading to greater growth,� he says.

You heard the man. Do it. Research shows that for experienced lifters, muscle fibers grow the most when you use weights that are 80 to 95 percent of the amount you can lift once. Beginners, go lighter: You will gain the most strength at 60 percent of your best effort. [source]