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Chenx15 03-02-2011 08:10 AM

physics/science behind pronation
 
I would like to understand the physics behind pronation. i am not sure how it makes the ball stay up and makes it spin to go down. i am doing it on my serves but for the life of me i can't understand the physics behind it. unlike ground strokes the science is pretty much straigh forward. if someone can please show me the physics behind the pronation on a serve it will be greatly appreciated. thank you.

dominikk1985 03-02-2011 08:43 AM

pronation does this:


Uploaded with ImageShack.us

Only works with a BH grip or conti grip though because it moves the rackethead around the hand and accelerates it. just try at home.

Chenx15 03-02-2011 08:51 AM

how does it make it spin up then down. when i am just observing is slowly and just rolling the ball on the racket i can't seem to understand it.

is there an illustration of the biomechanical movement of the forearm pronation with the racket and a tennis ball?

larry10s 03-02-2011 08:52 AM

what make the ball go up and spin down has to do with bernulli principle and magnus effect and gravity
pronation has to do with the anatomical movement of your forearm
as you approach contact.
if you serve with a continental grip or eastern bh grip you have to pronate some to hit the ball with the strings of the racquet
pronation also adds to racquet head speed which causes the ball to spin faster and allow the physics of ball spin to take over.
hope my abbreviated somewhat simplistic answer helped

toly 03-02-2011 08:53 AM

Quote:

Originally Posted by Chenx15 (Post 5459446)
I would like to understand the physics behind pronation. i am not sure how it makes the ball stay up and makes it spin to go down. i am doing it on my serves but for the life of me i can't understand the physics behind it. unlike ground strokes the science is pretty much straigh forward. if someone can please show me the physics behind the pronation on a serve it will be greatly appreciated. thank you.

About physics behind pronation on a serve you can read thread http://tt.tennis-warehouse.com/showthread.php?t=361610

larry10s 03-02-2011 08:55 AM

Quote:

Originally Posted by Chenx15 (Post 5459513)
how does it make it spin up then down. when i am just observing is slowly and just rolling the ball on the racket i can't seem to understand it.

is there an illustration of the biomechanical movement of the forearm pronation with the racket and a tennis ball?

brian gordon has a tremendous series of articles on the biomechanics of the serve which discusses this and more
www.tennisplayer.net
you will need to join for a month
when you log in you will see biomechanic on the left click on that and you will get to his articles

dominikk1985 03-02-2011 08:57 AM

Quote:

Originally Posted by Chenx15 (Post 5459513)
how does it make it spin up then down. when i am just observing is slowly and just rolling the ball on the racket i can't seem to understand it.

is there an illustration of the biomechanical movement of the forearm pronation with the racket and a tennis ball?

It's quite easy:

with a FH grip pronation moves the edge of the racket up this creating topspin on a WW forehand.

with a BH or conti grip on a serve it moves the face forward thus creating ball speed.

sureshs 03-02-2011 09:04 AM

Quote:

Originally Posted by Chenx15 (Post 5459446)
I would like to understand the physics behind pronation. i am not sure how it makes the ball stay up and makes it spin to go down. i am doing it on my serves but for the life of me i can't understand the physics behind it. unlike ground strokes the science is pretty much straigh forward. if someone can please show me the physics behind the pronation on a serve it will be greatly appreciated. thank you.

If you try to hit a ball with a conti grip and swing the racquet on edge, what should theoretically happen? You would hammer the ball with the frame. The fact that you don't is because of pronation.

Chenx15 03-02-2011 09:18 AM

Quote:

Originally Posted by sureshs (Post 5459537)
If you try to hit a ball with a conti grip and swing the racquet on edge, what should theoretically happen? You would hammer the ball with the frame. The fact that you don't is because of pronation.

I understand that, the ball should be moving sideways instead of up and down. because pronation is a horizontal brush instead of vertical

sureshs 03-02-2011 09:21 AM

Quote:

Originally Posted by Chenx15 (Post 5459568)
I understand that, the ball should be moving sideways instead of up and down. because pronation is a horizontal brush instead of vertical

Now imagine how you would hit a flat serve with a conti grip.

toly 03-02-2011 09:39 AM

Quote:

Originally Posted by Chenx15 (Post 5459568)
I understand that, the ball should be moving sideways instead of up and down. because pronation is a horizontal brush instead of vertical

If you use continental grip and keep the wrist in neutral position during impact, pronation cannot produce brushing motion at all. But, wrist ulnar deviation can create topspin, sidespin etc.

larry10s 03-02-2011 10:26 AM

Quote:

Originally Posted by Chenx15 (Post 5459568)
I understand that, the ball should be moving sideways instead of up and down. because pronation is a horizontal brush instead of vertical

no
pronation is happening
while the arm is moving in an arc
the brush is not (rarely)horizontal or vertical its a blend of the 2
if you have heard the serving "tip"
hit up and out
thats whats happening

LeeD 03-02-2011 10:32 AM

Pronation has nothing to do with spin. It only adds rackethead speed, which you could spin or hit flat.
Hold racket close to an L. Now pronate. See how much muscleLESS effort adds to rackethead speed?

sennoc 03-02-2011 10:45 AM

Quote:

Originally Posted by LeeD (Post 5459745)
Pronation (...) only adds rackethead speed

At serves? Urban legend.

LeeD 03-02-2011 10:49 AM

OP is talking about serves only. He's already figured out how pronation helps in groundies.
Hold conti grip and try serving. You gotta pronate to flatten out your shots.

sennoc 03-02-2011 01:15 PM

Pronation as a source of racquet's head speed at serves is NOT IMPORTANT. Dot.

Read some scientific papers, learn how to serve properly, do not write things which are straight way to injuries.

GetBetterer 03-02-2011 01:26 PM

I'm going with sureshs on this one. I'll post if I disagree with anything about what he says.

LeeD 03-02-2011 01:29 PM

Do any of you even hit a serve you can brag about?
Of course not, you don't pronate. Talking recent postings who say pronation doesn't add rackethead speed and those guys.
Does pronation need active muscles? NOPE!

sennoc 03-02-2011 01:39 PM

LeeD, you have no idea about biomechanics of serves.

Pronation just rotates surface of racquet's head. You have to do that intentionally, this is a result of muscles' action. But this action doesn't mean that the velocity of racquet's head is significantly larger! Physically, pronation is not important source of energy. It adds NOTHING to kick serves and no more than 10% at flat serves.

LeeD 03-02-2011 01:41 PM

Yes, you of the 85 mph first serve telling someone not to pronate because it's of minor importance.
If pronation wasn't important to adding speed, everyone would serve with and eastern forehand grip.


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