Biomechanics - Levers Flashcards
A lever is a rigid bar which can rotate around a _______ point when a force is applied to overcome resistance.
FIXED
The fixed point which a lever rotates around is known as the fulcrum, and also what?
AXIS (A)
In the body, the (F) force being applied is usually __________, and the (R) __________ is the part of the body being moved.
FORCE = MUSCULAR
+
RESISTANCE = PART OF BODY BEING MOVED
Name the term for the distance between the force being applied and the axis?
FORCE ARM (FA)
Name the term for the distance between the resistance and the axis?
RESISTANCE ARM (RA)
What determines the type of lever?
ARRANGEMENT OF THE AXIS IN RELATION TO THE FORCE AND RESISTANCE
Explain “Stay FAR from dogs (ARF) because you’re AFRaid.”?
Remembering trick* FAR - 1st class ARF - 2nd class AFR - 3rd class
Which lever is the most common type in the body?
3RD CLASS
In the example of biceps brachii flexing the elbow, the weight of the forearm (resistance), is moved by biceps brachii contracting (_________), as it rotates around the elbow (_________)
(FORCE)
+
(AXIS)
If the force arm (FA) is longer than the resistance arm (RA), then we perform an action with _______ effort.
What is this called?
LESS
+
MECHANICAL ADVANTAGE
What changes the direction of movement without changing the magnitude of the applied force?
PULLEYS
example, lister’s tubercle, also lateral malleolus for peroneals
In an example of mechanical advantage, what happens when the (RA) resistance arm is longer than the (FA) force arm?
ALLOWS US TO MOVE OBJECT FASTER THROUGH RANGE OF MOTION
When applying resistance to a client’s movement, make the (FA) as ________ as you can.
LONG
Where is the axis located in a first class lever?
FAR or RAF
IN BETWEEN FORCE AND RESISTANCE
Name the lever best designed for balance?
1ST CLASS LEVER
The head sitting on the neck is an example of which type of lever?
1ST CLASS LEVER
A wheelbarrow or a bottle opener are examples of which class of lever?
2ND CLASS
What is the arrangement of a 2nd class lever?
ARF
AXIS - RESISTANCE - FORCE
Name the lever best designed for power?
2ND CLASS LEVER
Brachioradialis is an example of which type of lever?
2ND CLASS LEVER
When the axis is at one end, the force is in the middle, and the resistance is at the other end, which class of lever is it?
3RD CLASS LEVER
What is the arrangement of a 3rd class lever?
AFR
AXIS - FORCE - RESISTANCE
