Muscles That Move Us: Free KS2 Science Worksheet

What this worksheet teaches

This worksheet helps children understand that movement happens when muscles contract and pull on bones. It focuses on the upper arm as a clear, familiar example: when you bend your elbow to lift something, the biceps muscle on the front of the upper arm contracts and shortens, pulling the lower arm up. The short questions encourage children to notice what happens to their own arm as they bend and straighten it, linking the diagram to their own body. By colouring the flexing-arm picture, children also begin to picture muscles as soft tissues wrapped around the bones rather than abstract labels in a textbook.

Why muscles work in pairs

A key idea at Year 3 level is that muscles can only pull, never push. Because of this, muscles are arranged in pairs that work in opposite directions, often called antagonistic pairs. In the upper arm, the biceps bends (flexes) the elbow and the triceps on the back of the arm straightens (extends) it. When one muscle in the pair contracts, the other relaxes and is gently stretched. This worksheet keeps the vocabulary simple and age-appropriate, but the underlying concept is accurate and prepares children for more detailed work on the muscular system later in Key Stage 2 and beyond.

How to use this sheet at home or in class

Before children write anything, invite them to flex their own arm and feel the muscle on the front harden as the elbow bends. Then ask them to straighten the arm and notice how the back of the arm tightens instead. A common idea is that the bulge appears because the muscle grows or fills with air. Explain that the biceps is getting shorter and fatter as it pulls, and that it goes back to its usual shape when it relaxes. The colouring activity works well as a calm follow-up: encourage neat colouring of the bulging muscle and the fist, and use the picture as a talking point about other movements, such as kicking a ball or nodding the head, that also rely on muscle pairs.

Linking to skeletons, support and protection

Muscles do not work alone. The Year 3 curriculum also asks children to learn that skeletons provide support and protection as well as movement. You can extend this worksheet by discussing how bones give the body its shape and protect organs, such as the skull protecting the brain and the ribs protecting the heart and lungs, while muscles attached to those bones make movement possible. Drawing this connection helps children see the skeleton and muscles as one working system rather than two separate topics.

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