Kinesiology Biomechanics

Agonist

The muscle primarily responsible for a movement

Antagonist

The muscle that opposes the movement of the agonist

Reciprocal contraction

The simultaneous activation of the agonist and inactivation of the antagonist (e.g. jumping)

Co-contraction

Simultaneous activation of the agonist and antagonist (e.g. bicpes brachii, triceps brachii)

Biomechanics

The study of the effects and control of forces that act on and are produced by living things

Force

An action or influence that moves the body or influences the movement of the body
Units = Newtons (N)

Internal forces

Created primarily by skeletal muscles

External forces

Created by the ground, external loads, other individuals (e.g. forces created by an opponent playing sports), and passive forces (e.g. wind resistance)

Moment (M)

A force which tends to change the rotational motion of an object
Units = Newton Metres (Nm)

Centre of mass (COM)

The point in an object where the mass is evenly distributed in ALL directions

Moment arm

The perpendicular distance from the force at application to the point of rotation (unit = m)

Measurements of Kinematics

- Visual observation
- Goniometer
- Inertial sensors
- Optical or magnetic motion capture

Gold standard/best current technique of measuring kinematics

Optical motion capture

Measurements of Kinetics

- Manual assessment
- Dynamometer
- Force plates

Hand held Dynamometer

Records/measures force produced during isometric contraction

Isokinetic Dynamometer

Measures force during isokinetic contraction

Force plates

Measures forces in every direction