Movement Analysis

1. Movement Analysis Levers Levers are seen in everyday life as well as in sport and exercise. A level system is a rigid bar that moves around a fixed fulcrum with two forces applied to it. Levers can change the size or direction of the effort used to make a task more manageable.

2. Key Terms

3. The position of the fulcrum, resistance and effort will determine which class lever it is. • In the human body the muscluo-skeletal system creates levers around every joint. These allow us to move. The joint acts as the fulcrum, effort comes from contracting muscles and the resistances the body part being moved, plus any additional objects held or resistance met. • The body contains all classes of levers, but 3rd class levers are the most common. Three classes of lever

5. Key Terms

6. There are two main benefits of the lever system • Large loads can be moved with a relatively small amount of effort • The distance a resistance can be moved, or the speed with which it can be moved, can be increased without an increase in effort. The benefits of different levers

7. Working out the benefit of a particular lever, you need to look at the length of two arms. • The distance from the resistance to the fulcrum is known as the resistance arm while the distance from the effort to the fulcrum is known as the effort arm.

8. When a levers effort arm is longer than its resistance arm it is said to have mechanical advantage. • Levers with mechanical advantage can move large loads with a relatively small amount of effort. They have a high resistance force to effort ratio. • Second class levers always have mechanical advantage. Mechanical advantage

9. A levers mechanical advantage or disadvantage all depends on the length of the force arm and the resistance arm. • The force arm is the name given to the shortest perpendicular distance between the fulcrum and the application of force (effort). The resistance arm is the shortest perpendicular distance between the fulcrum and the resistance. • Perpendicular distance is simply the length of the line between either where the fulcrum and the resistance is labelled or the fulcrum and effort is labelled. • If we consider a long jumper taking off, we see how the second class lever, where the foot contacts the ground, has a high mechanical advantage because the effort arm is longer than the resistance arm. • The result of this, for the long jumper, is that the force produced by the muscles, which is relatively small, is able to drive the full weight of the athlete off the ground.

10. First Class Levers: mechanical advantage and disadvantage

11. Mechanical disadvantage is when the resistance arm is greater than the force arm. • This means that the lever system cannot move as heavy a resistance but can do it faster. • It also has a larger range of movement. Mechanical disadvantage

12. Mechanical disadvantage Break down

13. Mechanical disadvantage Break down

14. Mechanical disadvantage Break down

15. Second Class Lever First Class Lever Third Class Lever Sports examples of levers