Isolation training, where you focus on a single muscle, is nearly pointless for athletes. If your goal is to develop size, you need to perform complex lifts that recruit several muscle groups at the same time. So ditch moves like arm curls in favor of full-body movements like Chin-Ups. You’ll cause more muscle stimulation throughout your body, leading to more muscle growth. The following eight exercises are essential to anyone looking to pack on muscle mass fast.