Biomechanics: Levers Flashcards
What is the purpose of a lever?
Levers allow us to create movement that is greater than the force applied. The skeleton forms a system that allows us to move.
What 3 components are levers made up of?
Effort
Fulcrum
Resistance
In relation to levers, what does effort mean?
The location where a force is applied
In relation to levers, what does fulcrum mean?
The point at which a lever rotates
In relation to levers, what does resistance mean?
The location of the weight that is being moved
When drawing a lever diagram, how is effort represented?
An arrow
When drawing a lever diagram, how is fulcrum represented?
A triangle
When drawing a lever diagram, how is resistance represented?
A square or arrow
What rhyme do we need to remember to help us with levers?
FRE
123
Where is the body do we see a 1st class lever system?
Extension of the elbow
Movement of the neck
Which lever system is represented in the picture?
1st class lever system
Where in the body would we see a 2nd class lever system?
Plantar flexion at the ankle
Which lever system is represented in the picture?
2nd class
Where is the body do we see a 3rd class lever system?
Everywhere except elbow extension, the neck and plantar flexion at the ankle
Which lever system is represented in the picture?
3rd class
In lever systems, how is the force arm calculated?
The length of the line between where the fulcrum and effort are labelled
In lever systems, how is the resistance arm calculated?
The length of the line between where the fulcrum and resistance are labelled
Explain the mechanical advantages of the second class lever system
Can generate much larger forces
Has to lift the whole body weight
Explain the mechanical disadvantages of the second class lever system
Slow, limited range of movement
Explain the mechanical advantage of the 3rd class lever system
Large range of movement
Resistance can be moved quickly
Explain the mechanical disadvantage of the 3rd class lever system
Cannot apply much force to move an object
