Hypertrophy (hy-PER-tra-fee) is the term used to describe the heavy breakdown of muscular fiber specifically for the purpose of growing the muscle bigger and stronger. This action is best achieved by lifting at 85% of your max weight for a particular exercise and only about three days per week, so the muscles have ample time to repair and grow. Big weights+big rest+big food=BIG MUSCLES! (Hypertrophy training should be cycled in three-to-four-week runs to avoid injury and plateau.) See segment on strength and endurance.