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Exercise Science Portfolio
Levers

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Levers of the body

A lever can be defined as a structure that is hinged where a force is applied at one point and resistance applies its own force at another point.  Our bodies are made up of many different series of levers.  For a body part to be able to move properly it requires a series of levers to move muscles and bones.  A lever is made up of three different things: 1.) Fulcrum-  This is the point that allows the lever to rotate. 2.) Load-  This is the weight or resistance of the lever.  It is the force applied to the lever system that opposes movement. 3.) Force-  This is the force being applied against the lever system.  It is applied by the user of the lever system.

1lever.jpg

First Class Lever

2lever.jpg

Second Class Lever
 

3lever.jpg

Third Class Lever

Levers can be classified into three different sections.
 
First Class Lever
 
For this type of lever the fulcrum is between the force and the load. An example of this would be a see saw.
 
Second Class Lever
 
For the second class lever the weight is between the fulcrum and the force.
Ex. Wheelbarrow, Ankle joint.
 
Third Class lever
 
The force is located between the fulcrum and weight. An example of this would be a fishing pole or shovelling snow, and a bicep curl.
The body is made up mostly of third class levers.  Our movements are more adapted for speed and range rather than strength.