Force, Torque and Levers Flashcards
What is torque?
Torque is the effect of force on the rotational movement of a joint.
When is force generated?
Force is generated at the point of muscle attachment to the bone when an active muscle becomes tense
What other forces outside the body can cause movement?
Gravity and the weight of an object or body segment
What is a moment of force?
The product of the force and its distance from the fulcrum (force x distance).
What is a lever?
Rigid bar or structure that rotates around the fulcrum
What is the fulcrum?
centre of rotation/axis of rotation
What is force?
the motion
What is resistance?
load against the motion
What is the moment arm?
the distance between the fulcrum and the force
What is the resistance arm?
distance between the fulcrum and resistance
What are the three types of lever?
1st class, 2nd class and 3rd class
What is a first class lever?
the fulcrum is located between the force and resistance
What is a second class lever?
Resistance between fulcrum and force
What is a third class lever?
force is between fulcrum and resistance
What is the most common lever in the body?
Third class levers
What is the least common lever in the body?
First class levers
What is an example of a first class lever?
see-saw - posterior neck muscles, head back and forward
What is an example of a second class lever?
push up - the calf when plantarflexing
What is an example of the third class lever?
Swinging a bat - bicep curls
How is the type of lever determined?
By location of force, resistance and the fulcrum
