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Levers - Coggle Diagram
Levers
Lever systems in sport
and physical activity
Second class levers
Second class lever systems have a mechanical
advantage.
Third class levers
Third class lever systems are the most frequently occurring in
the body
Third class lever systems operate at a mechanical
disadvantage.
First class levers
First class lever systems are arranged so that the fulcrum is between the effort and the load .
This is the arrangement of a first class lever system.
Mechanical advantage and disadvantage
Lever systems that let you lift a heavier load are said to provide a mechanical advantage.
The position of each part of the lever system relative to each other will determine whether the lever has a mechanical advantage and can be used to lift heavy loads or a disadvantage where greater effort is needed but the load can be moved a greater distance and with speed.
Lever systems in the body
The load is the object requiring moving, the effort is the muscular force we use to move the object, the fulcrum is the joint around which the movement occurs and the bones of the skeleton are the levers.
Imagine a road is blocked with a fallen tree. By placing one end of a long length of wood under the fallen tree and then pushing down on the other end of the wood, the fallen tree could be moved.
Planes and axes
of movement
Planes of motion
There are three major planes and axes in the body.
Plane – an imaginary line or flat surface that is used to divide the body
Axis – something that the body, or a body part, can rotate about Sagittal
Plane – line dividing the body vertically into left and right sides
Frontal plane – line dividing the body vertically into front and back
Transverse plane – line dividing the body horizontally from front to back
The major body axes
We know from Chapter 1 that in order for our bones to move, movement has to take place around a joint. In this example an axis passes through the elbow joint allowing movement around it.
