In this topic, students will develop knowledge and understanding of the basic principles of movement and their effect on performance in physical activity and sport through the following content. The topic guide will be available here.
Levers
Levers are made of bones, joints and muscles. They make movement possible and are represented by the following:
The square represents the load. This is what the lever is moving.
The line represents the lever arm. This would be the bone present in the lever.
The triangle represents the fulcrum, this is where bones pivot around a joint.
The arrow represents the effort, this would present where the muscles are, as they contract to create movement.
Load and Effort Arm
The load arm is the distance from the load and the fulcrum. The effort arm is the distance from the effort and fulcrum in a lever. A lever with a further effort arm, will have a mechanical advantage. On the other hand, if the load arm is further, it will have a mechanical disadvantage. In a second class lever, the load arm and effort arm is as shown:
Load arm
Effort Arm
First Class Levers
In first class levers, the fulcrum is in the middle of the load and effort.
When talking about first class levers, think about a see-saw as the two people on either side represent the load and effort which are on either side of the pivot.
An example of this:
Neck joint when heading a ball in football
This can be presented as:
Third Class Levers
In third class levers, the effort is in the middle of the fulcrum and load.
Third class levers have a mechanical disadvantage because the load arm is longer than the effort arm. An everyday example of this type of lever is a pair of tweezers.
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An example of a third class lever in the body is the elbow joint when doing a bicep curl.
This can be presented as:
Second Class Levers
In second class levers, the load is in the middle of the fulcrum and effort.
An example of a second-class lever is a wheelbarrow. The wheel acts as a pivot and the load is carried in the middle whilst you push it at the opposite end of the wheel. They are thought to have high mechanical advantage because the effort arm is longer than the load arm.
A Practical example of this:
The ankle joint when running in any activity.
This can be presented as:
Planes and Axes
Planes and axes are used to locate specific movements. Planes are the way the body is divided. Axes are the turning points. There are three types of planes and axes you must know of:
The Sagittal Plane
The sagittal plane divides the body in left and right. Any movement that takes place forwards or backwards takes place in this plane. An example can be running forwards.
The Frontal Plane
The frontal plane divides the body in front and back. Any movement that takes place sideways will be in this plane. A cartwheel is an example of this.
The Transverse Plane
The transverse plane divides the body in top and bottom. Any movement that rotates around the midline without adduction or abduction.
The Frontal Axis
The frontal axis runs from the back to the front of the core. Example of movement here can be a cartwheel as it rotates sideways.
The Vertical Axis
The vertical axis runs through the middle of the body. Movement here would be rotational, whilst standing. An example is a 360° twist on the trampoline.
The Transverse Axis
The transverse axis goes horizontally through the hips. Movement in this axis would rotate front/backwards. An example is a somersault.
