Major Muscles of the Body

This lesson covers the 11 major muscles required by the OCR GCSE PE specification (J587). You need to be able to identify each muscle, know its location, understand the movement it produces, and apply this knowledge to sporting actions.

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The 11 Required Muscles

The OCR specification requires you to know the following muscles:

Muscle	Location	Primary Action
Deltoid	Shoulder (covering the shoulder joint)	Abduction, flexion, and extension of the arm at the shoulder
Trapezius	Upper back and neck	Moves and stabilises the scapula; extends and rotates the neck
Latissimus dorsi	Lower and mid back (large, flat muscle)	Adduction, extension, and rotation of the arm at the shoulder
Pectorals	Chest (front)	Adduction, flexion, and rotation of the arm at the shoulder
Biceps	Front of the upper arm	Flexion at the elbow
Triceps	Back of the upper arm	Extension at the elbow
Abdominals	Front of the trunk / stomach area	Flexion of the trunk (bending forward), rotation of the trunk
Quadriceps	Front of the thigh	Extension at the knee
Hamstrings	Back of the thigh	Flexion at the knee, extension at the hip
Gluteals	Buttocks	Extension, abduction, and rotation at the hip
Gastrocnemius	Back of the lower leg (calf)	Flexion at the knee, pointing the foot (raising the heel)

Exam Tip: The OCR specification requires 11 muscles including the trapezius. Make sure you can locate all 11 on a diagram. Practise labelling a blank body outline from memory — this is a common exam question format.

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Detailed Muscle Guide

Upper Body Muscles

Deltoid

The deltoid is a thick, triangular muscle that covers the shoulder joint, giving the shoulder its rounded shape.

• Location: Covers the top and outer edge of the shoulder.
• Origin: Clavicle and scapula.
• Insertion: Humerus.
• Actions: Abduction (raising the arm sideways), flexion (raising the arm forward), extension (moving the arm backward) at the shoulder.
• Sporting examples: Raising the arms overhead in a basketball shot; lateral raise in the gym; swimming front crawl (arm recovery phase); throwing a javelin.

Trapezius

The trapezius is a large, diamond-shaped muscle that covers the upper back and the back of the neck. It is one of the largest muscles in the back.

• Location: Upper back, extending from the base of the skull down to the mid-back, and across to the shoulders.
• Actions: Elevates (shrugs), retracts (pulls back), and depresses the scapula. It also extends and rotates the neck.
• Sporting examples: Shrugging the shoulders when lifting weights; stabilising the shoulders during a rugby tackle; holding the head up during cycling; pulling the scapulae together during a rowing stroke.

Exam Tip: The trapezius is an OCR-specific muscle that you must know. Its key role is in moving and stabilising the scapula. Think of it as the muscle that controls your shoulder blades.

Latissimus Dorsi

The latissimus dorsi (often called "lats") is a broad, flat muscle covering the lower and mid back.

• Location: Lower and mid back, extending from the lower spine and pelvis to the humerus.
• Actions: Adduction, extension, and internal rotation of the arm at the shoulder. It pulls the arm downward and backward.
• Sporting examples: Swimming front crawl (pull phase — pulling the arm through the water); performing a pull-up; rowing (pulling the oar through the water); rock climbing (pulling the body upward).

Pectorals

The pectorals (pectoralis major) are the large chest muscles.

• Location: Front of the chest, from the sternum and clavicle to the humerus.
• Actions: Adduction, flexion, and internal rotation of the arm at the shoulder. The pectorals pull the arm across the body.
• Sporting examples: A chest pass in basketball; a forehand in tennis (pulling the arm across the body); a bench press in the gym; a push-up.

Biceps

The biceps (biceps brachii) is the muscle on the front of the upper arm.

• Location: Front of the upper arm, between the shoulder and the elbow.
• Actions: Flexion at the elbow (bending the arm).
• Sporting examples: A bicep curl; pulling back the string of a bow in archery; performing an upward rowing motion; bringing food to the mouth.

Triceps

The triceps (triceps brachii) is the muscle on the back of the upper arm.