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7 levers


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  • 1. Levers
  • 2. The Law of levers "The law of levers is the product of force and force arm is equal to the product of the resistance and resistance." The law of levers for swimming can be demonstrated in the arm stroke and the front crawl.
    Arm muscles provide the force and the shoulder is the pivot point. Water is the resistance, which comes from the arm during the strokes. The way to improve leverage is to use less force when swimming. For example, the front, crawl a swimmer can perform this by bending the elbow, this reduces the force when needed
  • 3. Levers are usually used to increase effort force so that loads can be moved more easily. In any lever system, you can identify three parts. They are the:
    Effort (the force being put into the lever system)
    Load (the object or resistance that the effort force is acting against) and
    Fulcrum (the pivot point that the lever turns around).
  • 4. A lever is known as a 1st, 2nd or 3rd class lever depending on which part-the effort, the load or the fulcrum-is in the middle of the system.
    When the fulcrum is in the middle, the lever is a 1st class lever. When the load is in the middle, the lever is a 2nd class lever. 3rd class levers have the effort force in the middle
    Classes of Levers
  • 5. Each lever class works in particular way to increase effort force or distance.
    First class levers that have uneven load and effort arms can either magnify force or magnify distance, depending on which arm is longer! They can also be used to change the direction of a force.
    Classes of Levers
  • 6. Second class levers can magnify force. The longer the lever arm, the greater the force magnification. Try pushing open a door at a point near the door knob, then try pushing it from near the hinge.
    Third class levers magnify movement. You use a third class lever when you sweep with a broom. The broom’s long handle gives you greater reach for your effort.
    Classes of Levers
  • 7. The only lever that applies to the front crawl is the third class lever. The deltoid, in the case of the upper body, is the fulcrum. The force is given from the deltoid and the resistance is the water. In the case of a third class lever, resistance and force move in the same direction.
    There is a loss in mechanical advantage because it takes a tremendous amount of energy to pull enough water to accelerate the body. The positive part of a third class lever is the gain in distance and speed of movement.
  • 8. Example:3-inch deltoid, 31-inch arm, pulls 11 pounds3 inches * F = 33 inches * 11 pounds3F = 363F = 121 pounds 121 pounds of force is put on the deltoid to move an 11 pound force. These are the laws that apply to swimming the front crawl. All these laws work together to make the body move as efficiently as possible through the water producing the fastest time possible in the pool. By understanding these laws it makes it much easier to understand and teach the front crawl to all levels of swimmers.
  • 9. Freestyle: How the Pros do it!
  • 10. Ian Thorpe - Freestyle
  • 11. Tips from an Aussie Champion: Ian Thorpe
  • 12. Body position in the water
    Almost horizontal to the water
    Full stretch with eyes forward for streamline
    If completely horizontal – you lose the power of your kick
    Tips from an Aussie Champion: Ian Thorpe
  • 13. 2. Breathing
    Never allow your head to submerge
    Breathe behind the bow wave that your head creates
    High head position for easy rotation for breathing
    Chin nearly touching shoulder of arm completing the push-back phase
    Exhale gradually after the recovery and entry phase of the arm stroke while head turns back passed center line of the body
    Bilateral vs unilateral breathing
    Tips from an Aussie Champion: Ian Thorpe
  • 14. 3. The arm stroke
    Always maintain a long arm-stroke
    Always keep elbows higher that hands
    Hands always relaxed
    Pull with the palm of your hands, forearm and shoulder
    Continue to extend hand and arm after they enter the water outstretched in front of head and in front of body
    Scoop water in front and down the center line of body
    Full extension of arm for strong push-back
    Tips from an Aussie Champion: Ian Thorpe
  • 15. 4. The Leg Kick
    Begin kick from the hips slightly rotating the body for more force
    Bend knees slightly
    Fully extend the foot
    Heavily engage hamstring during upward motion
    Maintain a loose and relaxed ankle
    Allow heels to just break the surface of the water
    Don’t kick any deeper that the width of the body
    Tips from an Aussie Champion: Ian Thorpe
  • 16. 5. Body Rotation
    Natural body rotation from side to side on long axis
    Caused by the rotating action of his arms
    Tips from an Aussie Champion: Ian Thorpe
  • 17. How did your freestyle stroke compare to that of Ian Thorpe’s?
    Compare and contrast your stroke with Ian’s
    How long do you think it would take for you to get to an elite level of freestyle swimming?
    How do you stack up?
  • 18. Theory: Sociocultural Issues
    Prac: Partners swimming analysis / cooperative games / drafts handed back
    Looking Forward to Next Lesson: