Muscles and movement

In a nutshell

Muscles are an essential part of your body and the muscles attached to your skeleton help you move. In this summary, you will learn how joints, tendons and muscles allow you to move.

Bones and muscles

ligament	A body part that connects bones together.
joint	The point where two bones meet.
tendon	A body part that connects muscle to bone.

Muscles and movement

Muscles are made of cells that contract (shorten) and produce movement. When a muscle contracts, it pulls on a tendon which causes the bone to move. This only happens if the bone is part of a joint connected by a ligament.

Science; Animals, including humans; KS2 Year 3; Muscles and movement — 1. Humerus bone, 2. Bicep muscle, 3. Tendon, 4. Radius bone, 5. Ulna bone, 6. Ligament, 7. Tricep muscle.

Muscle pairs

Muscles can only pull in one direction so they must work together. One muscle contracts pulling the bone whilst the other relaxes and lengthens. To reverse the action, the muscle that was relaxed then contracts to pull the bone in the other direction.

Note: The muscle pairs must be of the same type. So, the heart is a muscle that pumps blood around your body. But this muscle won't work in a pair with your biceps because it is made of a different type of muscle.

Example

Triceps (1.) and biceps (2.) are an example of two muscles that work as a pair.

Movement	Bicep movement	Tricep movement
*Lifting the forearm*	Contract	Relax
*Lowering* *the forearm*	Relax	Contract

Science; Animals, including humans; KS2 Year 3; Muscles and movement

Science; Animals, including humans; KS2 Year 3; Muscles and movement