The muscular system gives humans their shape and helps them move their body. This inside guide to our muscles uses relatable examples, discussion questions, sidebars, and fact boxes to dive in to what makes the muscular system work. Age-appropriate language is used in conjunction with detailed photographs and diagrams to explain key concepts such as main muscles in the body, and ways muscles can be strengthened or weakened. Your readers will gain a deeper understanding of the primary functions of the muscular system, including maintaining posture, strength, and movement.