Major skeletal muscles and their actions

Overview

The functions and structure of skeletal muscle, and the actions of the pectoralis major, deltoid, erector spinae, latissimus dorsi, trapezius, biceps, triceps, abdominals, gluteus maximus, quadriceps, hamstrings, tibialis anterior, gastrocnemius and soleus.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What are the main functions of skeletal muscle?

   Model answer

   Skeletal muscle contracts to pull on bones and produce movement. Skeletal muscle also maintains posture and stabilises joints. Muscle contraction generates heat as well.

2. 2

   Describe the structure of a skeletal muscle.

   Model answer

   A skeletal muscle is made of bundles of long fibres wrapped in connective tissue. Tendons attach the muscle to a fixed origin and a moving insertion.

3. 3

   Where is the pectoralis major, and what does it do?

   Model answer

   The pectoralis major covers the front of the chest and horizontally adducts the shoulder. A netball player uses it to drive the arms forward in a chest pass.

4. 4

   What is the role of the deltoid in sport?

   Model answer

   The deltoid caps the shoulder and abducts the arm. A volleyball player uses it to raise the arms for a block.

5. 5

   What is the role of the erector spinae?

   Model answer

   The erector spinae run either side of the spine and extend the back. A rower uses them to straighten the back in the drive.

6. 6

   What is the role of the latissimus dorsi?

   Model answer

   The latissimus dorsi is a broad back muscle that extends and adducts the shoulder. A swimmer uses it to pull the arm through the water.

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