Interactive Forum: Racket Head Speed

[johnyandell]

This month’s topic in the Interactive Forum is “racket head speed.” It’s the newest magic mantra in tennis. The pros have it and everyone wants it.


But what is racket head speed anyway? When is the racket going how fast at what point in the swing?


Can racket head speed be isolated and analyzed apart from an overall discussion of the stroke? Some coaches argue that the loop backswing is the key to “building” racket head speed over “distance.” The larger the loop the faster the racket. Others say the way to create racket head speed is with the over the finish “wrap.”


Another theory is that it’s the lower across the body swings that players like Federer and Blake use on a regular basis. Is that the secret?


These are great questions that await detailed answers. There is a limited amount of quantitative data from pioneering 3-dimensional studies, but very little information on the top players. It’s one of the new frontiers in tennis research, and we need to put more time, energy and especially, money into taking our analysis to this level. Truthfully I don’t see it happening for at least the next five years.


Which brings us to these two gorgeous high speed clips from Wimbledon. Shot with a high frame rate, but without a fast shutter, they are like moving impressionist paintings—and a window into the mysteries of how the racket moves for the top players. They may not give you any hard data, but they paint a very interesting picture. I want to know what you think that picture shows.


Study the racket path of Sharapova and Federer in these two clips. Look at the shapes of the swings. Watch the hand and racket move and how far and in what intervals. See what the shutter speed--or lack there of--reveals about when the acceleration really occurs and how long it lasts.


Now share what you think and we’ll talk about it over the next month!

[gzhpcu]

What I noticed, is that at the bottom of the swing, Federer supinates his forearm, which I think could cause more speed when coming forward (accentuates the pronation: stretch/contract)...

[kurtvanhook]

elasticity

The following words from John Early ("strokes that win") seem to key in on the aspects of sharapova's and federer's motions that might be central to generating racket speed....here he is walking the reader through a simple exercise:

".....swing the racket a few more times, but instead of simply allowing the racket to lag momentarily, actually move the racket back slightly as you begin to rotate the shoulders forward. In other words, instead of starting the racket movement in stationary position, complete your backswing a split second after the hip and shoulder rotation begins. With the arm and racket turning on one direction, and the shoulders turning in the opposite direction, you should feel a slight stretch followed by a quick burst of racket speed"

While this lag motion is admittedly only a single element of many that comprise the 'kinetic chain' of a well struck backhand....it seems interestng that there is a "stand out" aspect to this element in the vidoes shown above : you can clearly see this 'elastic lag' in the federer and sharapova clips. Also racket head acceralation at point of contact is acheived very soon after this elastic lag motion.

At any rate, perhaps this is one of the many "keys" towards creating greater racket head speed...???

as an aside- and at the risk of sounding pendantic:
Acceleration is defined technically as "the rate of change of velocity of an object with respect to time" and the instantaneous acceleration of an objection is given by the equation


where

a is the acceleration vector (as acceleration is a vector, it must be described with both a direction and a magnitude).
v is the velocity
t is time
d is Leibniz's notation for differentiation

a = dv/dt


Max acceleration, with is acheived when the ball is struck in the super-efficient world of Roger Federer, occurs, not coincidentally I think, very soon after the elastic wrist lag happens.

Kurt VH

[gzhpcu]

I think it could be this elastic lag. Plus supinating at the right moment accentuates it...

[jkfisch1]

With Sharopova she swing as fast as she likes because her swing is sraight forward only a little down in her swing. Rogers swing go's down. His take back is normal but a split second before contact he almost cocks the racket and then fires. After contact his swing is very fast then slows down. both Rogers and Sharapovas tack backs seem normal but in sharapova she has more time to swing forward. In Rogers he has that time but does not use it. Like I said he cockes his racket and fires. That's my opinion.

[vmiller]

The "elastic lag" is typically referred to as the "stretch-shorten cycle" by most biomechanists and I think many of them would agree that it's a big part of creating racket speed.

Fed and Sharipova are hitting two entirely different balls, but it appears to me that Sharipova's swing path is much more linear and through the ball. I guess that's to be expected though.

[shootermcmarc0]

I don't think he purposely supinates his forearm. I think what you see there is the result of the forward swing and the weight of the racquet in his hand, nothing special to it.

[sticks]

It's basically a serve in a different plane.

*racquet head drop
*shoulder load (probably key for women that don't have forearm/bicep strength, clearly seen in Sharapova video)
*external/internal arm rotation
*hand/racquet turns over
*chest stretch
*sometimes knee bend and body snap
*sometimes rt leg kick back
*left hand stretches toward contact zone then pulls around and in to stop rotation
*various exertions/counter-exertions creating whiplash
* and so on ...

Gotta have the correct shoulder load and arm motion in the serve though before you can transfer the feeling to the forehand.

Key is the "loaded" or taut shoulder connecting the arm to the body. Loose wrist, oily wrist advice can lead to a spaghetti arm, or "arming the ball". Basically the shoulder dis-connects. Typical in the club-level 4.0 to 5.0 serve and forehand. False sense of racquet head speed.

[stroke]

I have never thought Maria's forehand is very pretty shot, she does not start her swing with her hand behind the line of the ball, she has what may be too large a backswing and it appears to take a lot of effort to produce the shot. It looks like a lot of arm action to me. Roger's FH is, of course, beautiful to watch. A very short backswing, hand directly behind the line of the ball, and he seems to throw the racquet face into the ball, almost like a kind of short sidearm kind of throwing motion. I would think his racquet head speed is about as good as it gets, and of course, it seems effortless.

[JanWaechli]

racket head speed

i totally agree with the elastic lag comments, but do not forget the legs in the chain. (fedi uses them even in this low ball) i would also say, that fedi probably has to hit a lot of spin in this ballcontact-court-position, hince more rist action, and maybe even leg upward movement.

[gzhpcu]

The clip also shows very nicely how long Federer keeps his head watching the contact point after impact...

[jhm36]

You're right, Jan. I've got the match taped. Federer is hitting the ball just inside the baseline, passing Ancic who has hit a shoestring backhand volley. Fed's ball lands a foot or two behind the service line, so it doesn't travel very far in the air. He's getting much more topspin, I imagine, on that low ball than Maria does with that higher drive she's going for. My bet is that she's trying to drive the ball flat and deep, while Fed was trying to get the ball down on, and by, Ancic.

I like Federer's smaller, more compact backswing, something to learn from.

And how about his closed his racquet face is compared to Maria's?

I happen to have been experimenting with a greater stretch back towards the fence on my backswing and have been getting positive results from it. Feels to me like the swing is faster and I'm no doubt getting more topspin on the ball even though the motion doesn't feel like it's going more low-to-high than normal. Balls that use to land a little long are now coming down in front of the baseline. Good feeling.

Also working on more chest-stretch while serving, but that's really thrown off my motion. That's going to take longer to see positive results from. Feels like it's the thing to do, though. Like that way leads to a better serve. I'm going to be sticking with it. I'm not in any leagues where I have to worry about breaking down and lossing matches that count.

Good topic. I like the compare and contrast format of the thread.

[lannonk]

Wrist Relaxation

What I see is a major difference in the timing of the wrist relaxation/stretch. Both Maria and Roger seem to take the racquet back with a 45 degree wrist bend. Both seem to contact the ball with about a 45 degree wrist bend. The difference seems to be that Maria relaxes her wrist to 90 degrees at the very begining of her forward motion, and achieves her 45 degree contact bend well before striking the ball. Feds starts the drive forward with the butt cap with the wrist still at the 45 degree angle, relaxes/stretches to the 90 degree angle shortly before contact, and achieves the new 45 degree angle on contact. I believe that this last instant change from 90 to 45 degrees results in additional racquet head speed without a wrist snap or slap.
Now, how do I learn to do this?

[gzhpcu]

How to do it? IMHO: supinate your forearm at the bottom of swing just as you move your hip forward - slingshot effect...

[ozzytennis]

Racquet speed

Federer has more racquet speed due to the prestretch. His swing is more efficient and effective as a result.It all do with the position of the wrist in the preparation and keeping a loose grip. That simple.