Biomechanics Flashcards
Force exerted on a system or on some of its components by a source outside of the system
External forces
Stretching force (tension) pulling at both ends of a component or structure along its length
Tensile force
Pushing force whose direction and point of application would tend to shorten or squeeze an object along the dimension coinciding with the line of action of the force.
Compressive force
Force between two objects (or an object and a surface) that are in contact with each other
Contact force
Force acting on body when not in motion, but when force is acting on it.
Frictional force
Muscle whose torque prevents movement at a joint
Stabilizer
Role of a muscle whose torque cancels or eliminates the undesired effect of the torque produced by another muscle at the joint to allow a desired movement only
Neutralizer
Muscle the causes an action
Prime mover
A single sided or unbalanced load or weight distribution
Asymmetrical load
Capacity to do work
Energy
Transfer of energy by a force acting to displace the body
Work
Energy possessed by a body because of its motion
Kinetic energy
Energy stored by an object by virtue of its position
Potential energy
The rate of doing work
Power
A unit of power equal to one joule per second
Watt
Turning effect created by a force about an axis
Torque
Force whose line of action passes through the center of gravity of an object
Centric force
Force whose line of action does not pass through the center of gravity of an object
Eccentric force
Distance between the fulcrum and the resistance point
Resistance arm
Torque created by a pair of oppositely directed forces about an axis
Force couples
Relation of a muscles pull to the joint
Line of action
Point of where the mass of object is equally balanced. Also called center of mass
Center of gravity
Group of body segments that are connected by joints and operate together to provide a wide range of motion for a limb
Kinetic chain
As a rotating body spins about an external or internal axis (fixed or unfixed) it opposes any change in the body’s speed of rotation that may be caused by the torque
Rotational inertia
Product of momentum of rotating body and its distance from the axis of rotation. Amount of rotation of the body
Angular momentum
Role of a muscle whose torque opposes the action referred to or muscle referred to
Antagonist
Role of a muscle whose torque aids the action referred to as the prime mover
Agonist
The force production relationship between an agonist and antagonist muscle or group of muscles
Strength balance
Stable state characterised by cancellation of all forces by equal opposing forces
Balance
Sum of all external forces acting on the body equal zero; determines the ability to balance
Static equilibrium
Kinetic transferred into potential energy and back into kinetic energy for increased force output
Strength shortening cycle
Components of stability are (4)
Mass of object
Height of center of gravity
Line of gravitational pull
Base of support
Force exerted by one part of a system on another part within the same system
Internal force
