1. 2.1 Lever systems, examples of their use in activity and the mechanical advantage they provide in movement.

2. **DISCUSS your answers with a partner then feedback to the group**
Thinking of every day situations, how many examples of levers can you think of?
**DISCUSS your answers with a partner then feedback to the group**
Task 1

3. How does the body use levers to bring about movement?

4. You will need to identify and describe…
…the difference between:
FIRST CLASS
SECOND CLASS
THIRD CLASS levers
Explain the MECHANICAL ADVANTAGE of levers
Explain the DISADVANTAGE of lever systems
Analyse the use of lever systems in a physical activity.

5. Levers Levers consist of four components:
LOAD- this is the object requiring moving
EFFORT- this is the muscular force we use to move the object
FULCRUM-this is the joint around which the movement occurs
LEVER- the bones of the skeleton are the levers
Photo by: © deshow.net

6. Levers
The joints of our skeleton not only allow movement, they also act as LEVERS.
Photo by: © LOCOG
The function of levers are to increase the speed at which a body can move.

7. Levers
The human body is a system of levers and pulleys which enables us to move.
The joint itself is the fulcrum (Pivot).
This fulcrum 'takes the strain' of pulling one near, or away from another bone.
Photo by: © LOCOG

8. Levers
The levers rotate around a series of joints. The force is provided by the muscles attached to the bone (think of the muscles acting as pulleys).
The resistance comes from body weight and any implement used for sport (e.g. a bat or racquet).
Photo by: © deshow.net

9. Levers can be classified as: First class Second class Third class
Class of lever
Levers can be classified as:
First class
Second class
Third class
Photo by: © deshow.net

10. Class of lever – First Class
This is a lever where the Fulcrum (pivot) occurs between the effort and load.
Effort
Load
Lever Arm
TASK 2:
Replace the labels on this diagram to replicate what is happening when we nod our head.
Photo by: © deshow.net
Fulcrum

11. Muscles in neck contracting
Class of lever – First Class
The head is a good example of the action of a first-order lever in the body when the head and neck are being flexed and extended, as in nodding.
Muscles in neck contracting
Weight of head
Neck joint
Photo by: © deshow.net
First class levers can increase both effects of effort and the speed of a body.

12. As many as you can in 1 minute!
Think of as many sporting examples as you can where a ‘flick’ or nodding of the head is important…
As many as you can in 1 minute!
* Discuss answers as a group to add more to your own list! *

13. Class of lever – Second Class
This lever occurs when the load is between the effort and the fulcrum.
Load
Lever Arm
Photo by: © deshow.net
Effort
Fulcrum

14. Class of lever – Second Class
When you raise up on to your toes you are using a second order lever.
Weight of body and gravity
Muscle working
Ankle joint
The foot is the lever bar.
Photo by: © deshow.net
Second class levers tend to increase the effect of the effort force.

15. As many as you can in 3 minutes!
Think of as many sporting examples as you can where a second class lever is used. Work with the person next to you to ‘think, pair, share’ your ideas.
As many as you can in 3 minutes!
* Discuss answers as a group to add more to your own list! *

16. Class of lever – Third Class
This lever occurs when the effort lies between the fulcrum and load. This is very common in human movement
Load
Lever Arm
Photo by: © deshow.net
Effort
Fulcrum

17. Class of lever – Third Class
In terms of applying force this is a very inefficient lever, but it allows speed and range of movement.
An example within the body is a bicep curl during flexion.
The weight
Arm
Bicep muscle
Elbow
Third class levers can be used to increase the speed of a body.

18. Draw the following examples as a lever system in your books:
Hitting a forehand hit with a tennis racquet
Performing a free hit in hockey
The action at the hip when we walk
The action at the knee when we kick a football

19. How do I remember all of the levers??
1.2.3= F.L.E!
1st class lever= Fulcrum is in the middle
2nd class lever= Load is in the middle
3rd class lever= Effort is in the middle

20. Mechanical Advantage
The body’s levers can be made even more effective by using rackets, oars, paddles, sticks and bats.
Photos by: © deshow.net

21. Mechanical Advantage
These pieces of equipment increase the length of the resistance arm of the lever. This in turn increases the speed at the end of the lever.
Photos by: © deshow.net

22. Mechanical Disadvantage
Most levers in the body are third class levers where the resistance arm is always greater than the effort arm (mechanical disadvantage).
The longer the resistance arm of the lever, the greater the speed at the end of it.
So when bowling or passing a ball the performers arm should be fully extended to generate the most force and with the greatest speed.
Photo by: © deshow.net

23. Mechanical Disadvantage
RECAP
Lever systems can be used to:
Move a heavier load
Move a load further and faster
Mechanical Advantage
Lever systems allow you to lift a heavier load and are said to provide a MECHANICAL ADVANTAGE.
An example of this is a car jack that will only lift a car (the load) a small distance, but requires relatively little effort.
Mechanical Disadvantage
Lever systems where a greater force needs to be applied than the load to move provides a MECHANICAL DISADVANTAGE.
An example of this is a drive in badminton, or a forehand hit in tennis- think of the speed and force generated on the shuttle cock and the power required to generate that.

24. Looking back…
Take a look back in your notes and see which lever system is said to have a mechanical advantage as opposed to a mechanical disadvantage.
The lever system that has the EFFORT further than the LOAD from the FULCRUM had an advantage.
The lever system that has the EFFORT nearer than the LOAD to the FULCRUM has a disadvantage.

25. Apply it! Label the following levers components.
What has stuck with you?
Label the following levers components.
Describe the 3 levers in the body (use diagrams to help illustrate your answer)
Explain the term ‘mechanical advantage’
Which class of lever always has a mechanical disadvantage?
Levers and mechanical advantage
Photos by: LOCOG

26. Practice it! Exam questions
Which one of the following describes a second class lever system? (1)
A The load is at the right-hand end of the lever
B The fulcrum is in the middle of the lever
C The load is in the middle of the lever
D The load and the fulcrum are at the same point on the lever
2. Label the lever system below (4)
Lever class = _______________________
Photo by: © deshow.net
___________
___________
___________

27. Practice it!
Exam questions
3. Which one of these shows how to calculate the mechanical advantage of a lever? (1)
A Effort arm x weight (resistance) arm
B Effort arm ÷ weight (resistance) arm
C Effort arm + weight (resistance) arm
D Effort arm - weight (resistance) arm

28. Practice it! Exam questions
4. Analyse how the following parts of the lever system allow the weight trainer in Figure 5 to lift the weight.
Photo by: © deshow.net
Fulcrum (2)
(ii) Effort (2)

29. Practice it! Exam questions
5. Figure 4 shows a basketball player jumping to execute a shot. Draw the lever system which operates at the ankle joint in the space below. Label the fulcrum, effort and load. (1)

30. Practice it! Marks Scheme: C i) Third class lever B
Load
Marks Scheme: C
i) Third class lever B
One mark for linking bone or muscle to component of lever system and one mark for linking this to its use in the biceps curl to lift the weight. For example: Fulcrum – elbow is the fulcrum (1) which allows the arm to bend/flex (1) Effort – biceps muscle provide the effort (1) which allows the weight lifter to lift the weight (1)
Effort
Fulcrum
Photo by: © deshow.net

31. Practice it! Marks Scheme:
5. Award one mark for labelling the effort, load / resistance and fulcrum in the correct order.