Levers Flashcards
What is the definition of lever systems?
The coordination of our bones and muscles to create movement
What is the definition of a fulcrum?
Axis of rotation
What 2 forces are applied at the 2 points in a lever?
Load and effort
What are the 4 parts of a lever system?
Lever
Fulcrum
Effort
Load/resistance
What are levers in the body?
Bones
What are fulcrums in the body?
The joint
What causes the effort force in the body?
The agonist muscle
What is the load/resistance in the body?
The body part or resistance to be moved
What are the 2 main functions of levers?
Generates muscular effort and overcome a load
Increase the speed of a given movement
What is the lever in the upwards phase of the biceps curl?
Radius and ulna
What is the fulcrum in the upwards phase of the biceps curl?
Elbow joint
What is the effort in the upwards phase of the biceps curl?
Biceps brachii (internal force - agonist)
What is the load in the upwards phase of the biceps curl?
Weight of forearm and free weight held
What is in the middle in a first class lever?
Fulcrum
What is in the middle in a second class lever?
Load
What is in the middle in a third class lever?
Effort
Definition of a load arm?
Distance from the fulcrum to the load
Definition of an effort arm?
Distance from the fulcrum to the effort
What type of lever system is extension of the elbow in an overarm throw?
First class Elbow joint in between load of ball/forearm and the effort of triceps brachii
What type of lever system is the ball of the foot when pointing toes?
Second
Load of leg/body is in between fulcrum of metatarsals/phalanges joint and the effort of gastrocnemius/soleus
How do you work out mechanical advantage using resistance force and effort force
RF/EF
How do you work out mechanical advantage using resistance arm and effort arm
EA/RA
How do you work out mechanical advantage using resistance distance and effort distance
ED/RD
What do the best levers have in terms of effort arm and load arm?
Long effort arm
Short load arm
What do the best levers have in terms of effort distance and load distance?
Long effort distance
Short load distance
Why are 2nd class levers always an advantage?
Effort arm always shorter than load arm so small effort can move large load
What is the disadvantage of second class levers?
Only over a small distance and at the expense of velocity.
Why is a third class lever never an advantage?
Load arm longer than effort arm
Large effort needed to move a small load
What is an advantage of third class levers?
Although can’t be an advantage, does allow greater range of motion and generates more momentum and move load at a higher velocity.
