levers Flashcards
what are the three components of levers
fulcrum - the joint
resistance - the load
effort - the insertion point of the muscle which is contracting
what do you write next to a lever question
FRE
123
what is in the middle of a fist class lever
fulcrum
where can first cless levers be found
extention at the elbow
flexion and extension in the neck
what is in the middle of a second class lever
the resistance
where can second class levers be found
plantarflexion at the ankle
(standing on your tip toes)
what is in the middle of a third cless lever
the effort
where can third cless lever be found
in all joints of the body
(apart from the same ones at first and second)
advantages of first class levers
can produce quick movements large range of movement
disadvantages of first class levers
not able to lift heavy loads
advantages of second class levers
able to lift heavy loads
disadvantages of second class levers
no able to produce quick movements
small range of movement
advantages of third class levers
can produce quick movements
large range of movement
disadvantages of third class levers
not able to lift heavy loads
what is the effort arm
the shortest perpendicular distance between the fulcrum and the effort
what is the resistance arm
the shortest perpendicular distance between the fulcrum and the resistance
what are the mechanical advantages and disadvantages of level arms
when the effort arm is loger than the resistance arm, this is a mechanical advantage
-can lift a large load with little effort, but moves slowly (only found in second class lever)
when the resistance arm is longer than the effort arm, this is a mechanical disadvantage
-cannot lift a large load, but can move small load quickly
