Interactive Forum: Hand and Forearm Motion

[gzhpcu]

what I still find baffling is that the ball is on the strings for only a couple of milliseconds, yet look at all the biomechanical pre- and post-contact elements which are in play! All of this to just determine the racket angle and direction for a very brief impact point!

[josef]

The problem is that some have posted here and MANY have posted before, slo-mo film. That film seems to show a bent elbow, a laid back wrist and flat raquet face at impact (ie facing the net and parallel to the baseline), and a racquet that appears to have traveled through contact (long enough for ball to leave strings) evenly across the court and not sufficiently low to high to impart top spin. The pronation, wrist flexion, elbow fold, pectoral pull, shoulder rotation continuation all appear to happen long after the ball has left the strings.

Maybe these guys are all "locked-up" and have more ab/hip/leg strength than we think, and all the stuff that happens after contact is just for balance and recovery for the next shot.

Also, if we had super, super slo mo, we may see just enough pronation, wrist flexion, and low to high path to cause what is clearly evident: a forehand traveling 50+ mph (sometimes close to 90 mph !!!!), high net clearance, lands usually closer to service line than baseline (another teaching myth for club players) and a ball that bites and explodes when it lands.

Pronation and Flexion as process
I believe you have to think of pronation and flexion as a process. It is not enough to look at the contact point. The arm may still be in a neutral or even supinated position and wrist may be in a laid back position but the important thing to noticed is that the arm /wirst was even more supinated/laid back and the process to get there is pronation/flexion.

The rising of the whole body as topspin component
Furthermore the arm pronation and wrist flexion is not the only topspin component but the rising of the whole body is also a factor. Thats old news but its is still true and very visible with federer how is rising beautiful on every shot.

It is about topspin not speed
In general i think that the vertical component (spin) is far more important than the horizontal.(wrist flexion is more about direction than power) Nadal and Federer are two different combinations of the swing path of the hand and the additional spin component of this arm wrist action. (BTW the term windshild wiper was used to describe this motion but is now rarley used or is there a difference ?)
Nadal adds alot of spin to a already spin oriented swing path of his hand.
In contrast Federer combines a very straight swing path of the hand with alot of arm rotation. The results are high velocity balls and ample spin rates with a unheard margin of error over the net.

Federer nets very few forehands
A interesting category to look at is the number of unforced forehand errors that Federer hits into the net. I believe this category to be very small (around the numbers of his double faults). Only ball i can think of is the short cross any other forhand ball Federer has the luxury to stay at least two to three feets and often alot more away from the net. Its totaly different with his backhand topspin which he nets alot.

[andersedstrom]

federer turns it. nadal arms it.

the reason federer has a more effective forehand than nadal is that he keeps turning his shoulders through the shot.
nadal turns his shoulders up to the contact point but then he somewhat arms the rest of it.

take a look at the non raquet arm:
federer's left arm is closer to the other arm. therefore he is able to keep turning his shoulders.
nadal's non raquet arm goes too far ahead. therefore it stops once he gets to the contact point and forces him to push with the rquet arm the last bit through. his shoulder can't turn any more.

they both hit big forehands but i think federer uses less energy. nadal has huge arms but he doesn't hit harder or safer.

[lukman41985]

There is still widespread emphasis and belief in the closed or partially closed face--which occurs no doubt, but the relation to the hitting arm position is less well understood.

Yes and here is more evidence of the crucial hitting arm position from 10 of the biggest forehands in tennis: Nadal, Blake, Federer, Safin, Davydenko, Tursunov, Gonzalez, Roddick, Berdych, and Gasquet.

[lukman41985]

Continued...

[lukman41985]

Check out this sequence of Federer.

Looking at the sequence, cyberhound really gave a great description of what happens.

if you look from above the flex is not moving the racquet right to left which would destroy all control. It is moving it up and down. The plane of the racquet stays perpendicular to the flight path and the combination of arm pronation,flex and radial deviation moves the racquet head upward. This adds a lot of spin while allowing the swing plane to be through the ball.

Oh, and by the way, this sequence should also satisfy Eric.

This "stretch and release to contact" that happens for whatever physiologic reason (I wonder if an SSC plays a part) is a motion I've observed over and over again among elite forehands (In addition to the pronation part).

To prove this with more certainty, video would have to be taken from above

Check out the complementarity between frame 6 of this picture sequence and the frame that is 3 frames after contact in the above video.

[EricMatuszewski]

Thanks for posting that beautifull sequence. How did you get that?

[John Yandell]

You guys know that's a mishit right?

[alechorton]

Federer and Nadal from the right side

Perhaps if we get the correct perspective it will be easier to see.

Any comments?
Hope this helps,

Alec

http://www.tennisplayer.net/bulletin/attachment.php?attachmentid=134&stc=1

http://www.tennisplayer.net/bulletin/attachment.php?attachmentid=135&stc=1

[alechorton]

hand/forearm motion

It looks to be similar but the grip for nadal exagerates the Buggy-whip effect.
Also the perspective on the videos are a little different even if Nadal is now a righty!

Alec

[EricMatuszewski]

You guys know that's a mishit right?

Yes, frame 4 obviously shows a mishit. Fed has alot of mishits. It was shocking how many mishits I saw the first time I watched him up close in 2003. Yet his mishits frequently go in. He doesn't seem very bothered by them.

Also the above sequence shows Fed trying to run around a backhand and getting there later than he would've liked (he's still moving back and to the left after contact, and is slightly jammed).

It appears that he hit an inside out.

Nevertheless, it is a good view of the stretch of the flexors (frame 1) to acheive a less than 90deg angle between the racquet throat and the forearm, and the "rebound" effect to the aprox 135 degree angle at contact in (frame 2 to 3).

Another interesting quality of the sequence is the timecode above the stills. From "full stretch" to contact takes about 32 milliseconds in this example. My guess is that the racquet tip travels farther per unit of time in this stage of the stroke.

The distance moved by the racquet tip between frames 3 and 4 is much less, probably because the collision just happened, and the racket lost much of its kinetic energy.

As for the clips posted by alec, I had download problems and could not view them.

[lukman41985]

You guys know that's a mishit right?

Irrelevant. There is still a clear use of what Eric describes as "stretch and release"; the wrist goes from laid back to released from frames 3 to 5 in 0.034 seconds.

[cyberhound]

Nadal buggy whip

It looks to be similar but the grip for nadal exagerates the Buggy-whip effect.
Also the perspective on the videos are a little different even if Nadal is now a righty!

Alec

IMHO The Nadal buggy whip results from his hitting off the back foot off balance and on the run. Sampras and Federer do this as well in similar situations.

I think when Nadal is balanced and set before he swings, he ends with the finish by the elbow or hip.

[cyberhound]

Stretch and Release

Irrelevant. There is still a clear use of what Eric describes as "stretch and release"; the wrist goes from laid back to released from frames 3 to 5 in 0.034 seconds.

I agree. It's the SSC (Stretch Shortening Cycle) at work. If you tried to do this by conciously working the muscles instead of letting the reflex work, it wouldn't be nearly as fast and you would probably develop serious tennis elbow.

regards,

[cyberhound]

Mishits

You guys know that's a mishit right?

That's the one thing I can do as well as Federer, since I started hittiing my forehand this way. Spectacular mishits into the upper deck.