7 levers

Levers

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

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

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


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


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


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

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

Freestyle: How the Pros do it!

http://www.youtube.com/watch?v=vtfpfTUVWw0



Ian Thorpe - Freestyle

http://www.youtube.com/watch?v=-8qUpeDb8kI

http://www.youtube.com/watch?v=-8qUpeDb8kI

Tips from an Aussie Champion: Ian Thorpe

http://www.youtube.com/watch?v=5QrF2JkUdig



1. 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


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


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


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


5. Body Rotation Natural body rotation from side to side on long

axis Caused by the rotating action of his arms


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?

Theory: Sociocultural Issues Prac: Partners swimming analysis /

cooperative games / drafts handed back

Looking Forward to Next Lesson:

7 levers

Education

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