Racquet Acceleration

[JCo872]

Originally Posted by NamRanger

After watching a whole lot of groundstrokes and serves, it seems that pros really don't swing too fast before contact, but they seem to accelerate alot faster when they make contact. Anyone else notice this trend? It's like they are "finding" the ball first before they accelerate through it.



Roddick isn't the best example, but pretty much all pros that I've watched so far have this in common.



http://www.youtube.com/watch?v=V-D32RwsD_w


As you watch Roddick from his backswing to moving the racquet foward, you'll notice the racquet really doesn't take off till slightly before it makes contact with the ball, when the racquet DOES make contact, then it really starts to accelerate, much faster then the racquet's initial foward acceleration into the ball.



Here's a video of Tommy Haas practicing

http://www.youtube.com/watch?v=tDiNR...elated&search=


Notice how you can easily track when the racquet is moving foward initially, but when Haas makes contact, the racquet sort of blurs out as he starts accelerating through the ball.

Great observations!

Here is my take on this. So much power comes from contacting the ball well in front of the body with your body and hand properly positioned behind the ball. It's what pro strokes all have in common. I think this can be explained by the physics of spring.

When we watch high speed clips of pro strokes, we see the ball compress deep into the string bed and spring away. This spring event is maximized when the racket is in front of the body (leverage) and the hand and body are properly positioned behind the racket for support.

If you accelerate your arm and racket early, the arm and racket start to come across the body right away. You don't get the clean contact point in front of the body. Instead you get a swiping action. This is what I see on most tennis courts. Circular, fast swings around the body.

If you want to see a perfect contact point, pause the Federer clip on my homepage on contact. Watch how his arm is straight and the shoulder and hand are properly positioned behind the ball. He is getting maximum leverage and maximum support behind the racket for the ball to compress and spring away.

Try taking your arm and racket back and "swing fast" at the ball. Your arm and racket will never get into the position Federer is in. Instead you have to use upper body rotation and a lifting motion from the arm to achieve this kind of contact point.

If you watch Federer come into contact in that video, you will see his entire arm lift upwards, like he is bowling a bowling ball. This lifting motion, as opposed to a swinging motion, is what lets him get such a perfect contact point in front of his body. What you see today is lifting motions and pulling motions and rotating motions to acheive solid contact points in front of the body. You don't see "swings".

For another example, check out my clip of Verdasco:
http://www.hi-techtennis.com/video_s....swf&size=wide

Watch how he achieves such an amazing contact point with a straight arm and the strings flat on the ball. He doesn't do it by "swinging fast" into contact. All he does is rotate his upper body and lift his hitting arm to achieve a pro level contact point.

If you really want to spring in action, with leverage and body/support at work, check this out. Watch how the player almost "pushes" through the ball rather than "swings fast" at it:
http://www.hi-techtennis.com/forehand/flash/spring.swf

Jeff

[tlm]

the gorilla,
whatever you say gorilla, i did not agree with the first points john posted.But the last post made great sense, i thought he was right on the money.So you can say whatever, but when someone makes a good point i will recognize it.On top of that i did experience exactly what he was saying.

I have had some heated debates with john in the past and one thing about him is he would still answer questions from me, even though we had are differences.Maybe you should check out some past posts+ see how much i was sucking up to him gorilla.

[chess9]

I suspect that in the vast majority of impacts between racquet and ball, even at the pro level, the racquet starts decelerating upon impact. This is simple physics. To overcome the force of the ball (M x A), the acceleration at the point of impact would have to be greater than the sum of the racquet/arm force (M x A) + the force of the ball (M x A). Again, this strikes me as simple physics.

I'm sure someone has done these measurements and calculations.

-Robert