1 / 13

LEVERS

LEVERS. PE Workbook Pages 73 - 74. Levers. A lever is basically a rigid structure, hinged at some point and to which forces are applied at two other points. 1. Levers consist of 3 basic parts: Load or Resistance Fulcrum or Pivot Force or Effort. Levers.

norris
Download Presentation

LEVERS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LEVERS PE Workbook Pages 73 - 74

  2. Levers • A lever is basically a rigid structure, hinged at some point and to which forces are applied at two other points. 1. Levers consist of 3 basic parts: • Load or Resistance • Fulcrum or Pivot • Force or Effort

  3. Levers • Load or Resistance = the load or resistance that is needing to be moved. • Fulcrum or Pivot = the point around which the movement happens (in the body these are our joints). • Force or Effort = the point of force that drives the movement (in the body these are our muscles).

  4. Levers – page 73 2. Levers have two main functions. These are: • Move a resistance with a small input of force (eg: a crowbar) • Generate high velocities at one end that can be passed on to another object (move loads at a greater speed) eg golf club

  5. Levers – page 73 • Much of what we use in sport relates to the second point. • Longer levers (within reason) generate the greatest velocity at the end. • Consider the person swinging a golf club. 3. Does this mean that a golf club that was slightly longer than normal would give greater head speed? Try question 4……..

  6. 3. Yes it would. It assumes that the musculature of the player can generate and cope with the forces required. 4. So we strike with as long a lever as possible that is moved through as wide a range of motion as possible. Hand/ racquet will have more velocity.

  7. Classes of Levers • There are 3 classes of lever: • First class • Second class • Third class • Definition of First class lever (page 74) • The fulcrum lies between the load and the effort. • Eg. See saw. Lifting your head • Using this as your guide, try the definitions for Second and Third class……

  8. Classes of Levers • What did you come up with?? • You should have: • Second class = the load lies between the fulcrum and the effort. Eg opening a door, diving board, press ups, Standing on tip toes • Third class = The effort lies between the fulcrum and the load. Bicep curl. Softball bat • Answer questions 6a, b, c

  9. 6a. First class • 6b. To move a resistance with an input of force • 6c. If an oar is slightly longer, more force can be generated by the blade in the water meaning a greater resistance can be moved faster.

  10. Maximising lever length to improve performance • Shortening the lever arm (by bending the joint) allows the lever arm to generate force and to be rotated with more speed. • Then the lever arm can be lengthened (by straightening the joint) to maximise speed at the end of the lever. This can then be used to strike and propel objects more effectively. • The resistance arm of the body’s internal third class levers can be further lengthened by using implements, eg golf clubs, tennis rackets, softball bat.

  11. Maximising lever length to improve performance • If the body part is extended by a softball bat; the bat strikes the ball with more speed than your hand would. (external lever) • If your arm is fully extended when performing an overhand throw in softball it will generate more speed than if it was at a 90 degree angle. (internal lever)

  12. Lever Activity • Take class outside with a range of sports equipment such as patter tennis bat, tennis racket, softball bat. • Use tennis balls so that you can also try just ‘hitting’ the ball using the students’ hands. • Allow students time to have a turn with each of the sports equipment pieces then feedback about differences in distance, speed etc as a result of each different lever.

  13. Check this out!!!! Shogun Rua’s force http://espn.go.com/video/clip?id=6227046

More Related