Upcoming SlideShare
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Standard text messaging rates apply

# 7 levers

4,330

Published on

Published in: Education
0 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

• Be the first to like this

Views
Total Views
4,330
On Slideshare
0
From Embeds
0
Number of Embeds
4
Actions
Shares
0
47
0
Likes
0
Embeds 0
No embeds

No notes for slide

### Transcript

• 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
Levers
http://www.customessaymeister.com/customessays/Term%20Papers/1619.htm
• 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).
Levers
http://imaginationfactory.questacon.edu.au/assets/im_levers.pdf
• 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
http://imaginationfactory.questacon.edu.au/assets/im_levers.pdf
• 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
http://imaginationfactory.questacon.edu.au/assets/im_levers.pdf
• 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
http://imaginationfactory.questacon.edu.au/assets/im_levers.pdf
• 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.
Levers
http://members.fortunecity.com/magnusdr/coaching/freestyle.html
• 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.
Levers
http://members.fortunecity.com/magnusdr/coaching/freestyle.html
• 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
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: