How Muscles Move Bones

About this printable How Muscles Move Bones science reading passage, NGSS-aligned (Grades 3-5)

This comprehensive 250-word reading passage introduces fourth-grade students to the fundamental concept of how muscles and bones work together to create movement in the human body, aligned with NGSS 4-LS1-1 standards. Students discover that muscles can only pull, not push, which is why they must work in pairs to move bones in different directions. Using the relatable example of bending and straightening an arm, the passage explains how the biceps muscle pulls the forearm up while the triceps muscle pulls it back down. The audio-integrated content helps students understand the structure and function of the muscular and skeletal systems working together. This passage builds foundational knowledge about body systems and prepares students for hands-on investigations and deeper discussions about human anatomy. The simplified differentiated version ensures all learners can access the same core science concepts through shorter sentences and familiar language. Spanish translations of both versions support English language learners. Accompanying activities include multiple-choice comprehension questions, writing prompts that encourage application of concepts, and graphic organizers that help students visualize the cause-and-effect relationships and structure-function connections in the musculoskeletal system.

Written by Workybooks TeamPublished by Workybooks

Sample passage and quiz from How Muscles Move Bones

Your body moves because muscles and bones work together as a team. Muscles are body parts that can tighten and relax to create movement. Bones are the hard structures that give your body shape and support. This partnership allows you to run, jump, write, and do everything you need to do each day.

Muscles have an important rule: they can only pull, not push. A muscle works by getting shorter and tighter, which pulls on the bone it is attached to. Because muscles cannot push, your body uses muscle pairs—two muscles that work together to move a bone in different directions.

Your arm is a perfect example of muscle pairs at work. When you bend your arm, the biceps muscle on the top of your upper arm tightens and pulls your forearm up toward your shoulder. When you want to straighten your arm again, the biceps relaxes. Then the triceps muscle on the bottom of your upper arm tightens and pulls your forearm back down. One muscle pulls the bone one way, and its partner muscle pulls it back the other way.

This pulling system works all over your body. Muscle pairs in your legs help you walk and kick. Muscle pairs in your jaw help you chew food. Without muscles working in pairs, you would not be able to move your bones back and forth.

Interesting Fact: You have over 600 muscles in your body, and it takes 17 different muscles working together just to smile!