Biomechanics

1. Biomechanics Vocabulary

2. Agonist Antagonist Axis of rotation Concentric action Eccentric action Force Fulcrum Isometric Law of acceleration Law of impact and reaction Law of inertia Lever motion Motive force Protraction Resistive force Retraction Supine Synergist Torque Tuberosity

3. Agonist – a muscle that is directly engaged in contraction. • Antagonist – the muscle that acts in opposition to the action produced by an agonist muscle. • Axis of rotation – imaginary line or point about which the lever rotates. • Concentric action – the muscle acts as the motive force, it shortens as it creates muscle tension. • Eccentric action – contraction in which a muscle exerts force, lengthens and is overcome by a resistance. • Force: something that causes motion, push or pull • Fulcrum – a fixed point.

4. Isometric – a contraction in which a muscle exerts force but does not change in length. • Law of acceleration – F=MA. • Law of impact and reaction – Newton’s third Law; equal and opposite reaction. • Law of inertia – objects remain at rest or if moving continue moving. • Lever – a bar that rotates around a fixed fulcrum in response to an applied force. • Motion: change in an object’s position in relation to another object • Motive force – the force that starts or causes a movement. • Protraction – movement of the scapula away from the spine.

5. Resistive force- a force that resists the motion of another external force. • Retraction – movement of the scapula towards the spine. • Supine – position of the body when lying face upward. • Synergist – a muscle that assists another muscle in its function. • Torque – a force causing rotation about a fixed axis of rotation. • Tuberosity – a projection or protuberance on a bone usually serving for the attachment of muscles or ligaments.