Section A: Applied Anatomy and Physiology

5. Functions of muscles

Syllabus

• Function of muscles as agonists, antagonists, fixators and synergists

Function of Muscle

• The transformation of chemical energy into mechanical energy to:

– Generate force – Perform work – Produce movement

– Other functions include: stabilisation and generation of heat

Properties of Muscular Tissue

• Electrical excitability

• Contractility – Generates tension while pulling on its attachment points

• Extensibility– Ability to stretch without being damaged

• Elasticity – Ability to return to its original length and shape

Agonist

• The muscle that is directly responsible for the movement at a joint

• Also known as the prime mover

Antagonist

• A muscle that has an action opposite to that of an agonist (prime mover) and helps in the production of a co-ordinated movement

Synergist

• A muscle which contracts to enhance the efficiency of the prime mover by preventing any undesired movement

• It forms part of the co-operation or antagonist effect of the muscles which work together to ensure co-ordinated movement

• Also known as neutalisers