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Old 01-03-2012, 11:23 AM   #18
toly
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Quote:
Originally Posted by ho View Post
1/Leg and core rotation provide the major power in rotational movement
It’s true that leg and core rotation provide the major power, but with very low efficiency, from ball/racquet speed point of view. Most of this energy is wasted for rotation of 200 pounds and just a little bit is going to the ball.

Quote:
Originally Posted by ho View Post
2/Arm whip around shoulder provide the most racket speed in linear movement.
If arm is passive and moves like the whip, it cannot produce decent linear racquet speed.

Quote:
Originally Posted by ho View Post
(1) provide speed if you hit with body and arm as one unit.
It cannot provide a lot of speed because body and arm as one unit has very big mass. Thus, this unit would be relatively slow, compare with elbow or wrist motions.

Quote:
Originally Posted by ho View Post
Not the racket speed that give you the ball speed, but the compression of the ball against a solid object self create the ball speed.
The ball speed approximately is

Vballspeed = Vracquetspeed x (1 +K), (1)

Where K is coefficient of restitution.

If the racket has speed 80 mph, K is around 0.3. So, the compression of the ball cannot be the main factor. According to formula (1), the racquet speed is the main factor of the ball speed.


Quote:
Originally Posted by ho View Post
(2) provide racket speed but their is only the arm weight behind the racket, law of physic on colliding will indicate that ball speed will not always as much as (1) particular when ball coming in great speed.
See please my posts: http://tt.tennis-warehouse.com/showt...60#post5892760, http://tt.tennis-warehouse.com/showt...80#post5895380
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Last edited by toly : 01-03-2012 at 05:25 PM.
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