Before diving into specific workouts, let's look at a few ways you might be inadvertently holding back your overall deltoid growth. Typically, you'll experience a training plateau for three reasons, all of which need to be addressed to get back to building max muscle. Weak shoulders don't just look funny in the mirror; your shoulders are involved in chest, triceps, and even back training, and there's no way you want your delts to be a limiting factor.