Levers Flashcards
What are levers?
A means of applying force at a distance from the source of the force
They can help us to…
- Maintain balance
- Give greater speed to an object
- Overcome a heavy resistance with little effort
- Give a wider range of movement
3 components to every lever system:
- Effort point (E) - point at which the force supplied by a contracting muscle is applied
- Fulcrum (F) the joint itself
- Resistance (R) - the weight of what is being moved
First class lever is…
Fulcrum in the middle
At the tricep/elbow during an overhead throw
Function of 1st class lever is?
To increase the speed of an object
Second class lever is…
Resistance in the middle
At the ankle, using gastrocnemius during jumping, kicking & squatting
Function of 2nd class lever is?
To overcome heavy loads
Third class lever is…
Effort in the middle
At other joints (knee/bicep) during upward phase of bicep curl, kicking at the knee, jumping at the knee
Function of third class lever is?
Increases in speed/distance rather than overcoming heavy loads
Force arm is:
Shortest perpendicular distance between the fulcrum and the application of force
Resistance arm is:
shortest perpendicular distance between the fulcrum and the resistance
Mechanical disadvantage:
When resistance arm is greater than the force arm (able to move quickly rather than moving heavy loads)
Mechanical advantage:
A longer force arm (allows for more force to be developed and a large load can be moved over a short distance)
Increasing the length of resistance arm….
Increases the speed at the end of it
Allows more force to be exerted
Fulcrum is…
Where the bones meet - the joint
