Interactive Forum: Dec 2007 Federer Serve Upward Swing

[bottle]

To ruymendes 1

'superior manner' is right. That's where he went wrong.

[bottle]

Yes, all those things!

And as for you not getting the point of spaghetti arm
vs. muscular arm vs. accelerated-decelerated arm, look for Brian Gordon's
article in the next issue and GET OLDER.

Tour Technician Ben Ford thinks younger players don't know anything about tennis technique-- Billie Jean felt that way about the best players. Be that as it may, if anyone else wants to spat with me before I get out of here (the posts are raining about my head), I'll put a curse on em, and then they'll have a loose piece of bone in THEIR knee!

[stroke]

If you study the video of the top players, some of them have the big serves regularly and some are a notch or two off that pace.
What I've seen is that Pete, Andy, and the other consistent big servers delay the extension of the forearm from a very low wrist and high elbow till they are almost off the ground with their leg drive.

On the other side you can see the servers who are generally a notch or so off the top speeds and how they start to prematurely extend the elbow, lifting the wrist and racket. Agassi is a good one to look at for this. I have great respect for his serve, but on avg, we all know he is about 10-15% off the pace of faster servers. Guys like Agassi have already gotten thru 1/3 to 1/2 of that movement, at a point that the faster servers have not even started the extension. Roger usually falls somewhere in between these two groups with his serve. He delays the elbow extension longer than Agassi, but not as long as Andy, and with less leg drive as well.

One way to analyze this is to see that the racket for the big servers has about 1-2 feet farther to travel (at the top of the leg extension), in the same amount of time. That translates to more racket speed!

I don't see any great variation in their wrist except that as slower servers movement of the wrist starts sooner with the elbow extension as well.

This is a very interesting thread. To follow up on airforce1's thoughts, I think the best servers make a significant backwards action(to the right for a righthander) as the arm is lifted out of the drop to increase tension(supination) as the body in moving up and into the strike of the ball. This may tie in to airforce's thoughts on the delayed arm extension. This is kind of similar to the so-called stretch shortening cycle on the top forehands. Someone like Agassi does not really employ this on the serve. John mentioned this movement I believe in his articles on the Roddick serve and how Andy does this.

[airforce1]

This may tie in to airforce's thoughts on the delayed arm extension. This is kind of similar to the so-called stretch shortening cycle on the top forehands.

I really like the association you have made here.
thanks,

[bottle]

To anyone who still may feel miffed

Do you know how many articles by Brian Gordon already exist under "biomechanics"? Do you know that the moving graphic near the top of "The Serve and Tennis Science" shows an absolutely still elbow during the arm extension phase-- close to what Federer does in these two videos under discussion?

Do you know that:

. Gordon's research attributes 29 per cent of racket head speed at halfway point in elbow extension to elbow extension itself?

. Gordon's similar attribution for elbow extension measured just prior to contact is 35 per cent?

. That both of these figures reflect a contribution that is larger than other individual factors even including shoulder movement (also big) and hips and shoulders twist, wrist deviation sideways, wrist flexion (big), upper arm twist (less than Bruce Elliott thought?), forearm pronation (much, much less than almost anybody thought)?

Therefore, the how of elbow extension is a very important subject, and there are several distinct possibilities available for this with one very possibly being much better than the others.

[BrianGordon]

As for your question about the arm, that doesn't make sense to me. A bent arm can only straighten upward from the tricep muscle. It's a simple tricep extension, isn't it?

No - the dynamics are complex and intriguing - but during the most extensive part of the elbow extension the muscles crossing the elbow joint actually deter elbow extension - details coming - Brian

[jeffreycounts]

No - the dynamics are complex and intriguing - but during the most extensive part of the elbow extension the muscles crossing the elbow joint actually deter elbow extension - details coming - Brian

Interesting! Looking forward to the next article...

[mntlblok]

"Motion-dependent torque" comes to mind. . .

Kevin
Savannah

>>>>>>>>
As for your question about the arm, that doesn't make sense to me. A bent arm can only straighten upward from the tricep muscle. It's a simple tricep extension, isn't it?

[tennis_chiro]

What about the importance of hitting up

This is a great thread. A lot of deep thought backed up by some good evidence in high

speed video right here and in the shots that John forst got a couple of years ago of that

extreme supination on Roddick's serve. I was at the USPTA meeting in La Quinta when John

first unveiled that video and he was talking about guys getting additional mph with that

extreme (and a little scary) motion.

But Bottle has a good point. How do you do it? All the anatomical and biomechanical

analysis does not necessarily translate to helping the local hacker or anyone challenged to

get a great snap to achieve that goal.

It's good to analyze someone's motion and see that certain things might be missing and have

to be added, but technical terms don't translate to performance on the court.

So,...
a serve is like the snap of a towel when you make it "pop";
a serve is like the last person on the end of the "Whip" in a string of ice skaters;
a serve is like the last part of a golf swing when the club explodes into the ball at the

last minute.

That towel pops because the last little bit of the towel is going so fast trying to catch

up. All that energy gets to the end of the towel and has nowhere to go.

That person at the end of the "Whip" on the ice is going very fast even though the person

in the middle is hardly moving at all.

In a lot of slow motion video that you can see of golf pros, the last second snap of the

wrists is almost incomprehensible to most of us mere mortals. The position is almost

painful, but clearly they are doing something different and a lot of it is that last minute

snap right before and through impact.

A lot of it is related to the physics of tangential forces generated by

centripetal/centrifugal forces (I don't remember). Something like the tangential force is

proportional to the velocity squared (Brian, help me out here). You are trying to generate

a force upward through your arm all the way from your toes and redirect it perpendicular to

the direction you are actually throwing the racket (straight up). Since you are holding on

to the racket it can't go up and instead the force gets directed on the tangent off the

face of the racket into the ball. When you catch the ball cleanly on the right spot, it

really pops. It's one of the toughest things to get students (and I mean nationally ranked

juniors as well) to do consistently, is to hit that ball cleanly and not slide under or

around it (and I don't mean only flat serves).

If you are trying to reproduce this motion, recognize that the racket shaft is moving

toward the ball in a plane that includes the contact point and the target. That's

necessary to get an efficient transfer of momentum and power to the ball. But even as the

shaft is staying in that plane, the racket face is turning as shown here to a position

perpendicular to that plane.

I line my students up next to a fence with a windscreen (need a 10' fence). They take a

position about 18" from the fence to the front foot or shoulder. There isn't room to take

the initial position so I have them take the backswing first and stop with the racket in

the backscratch (a non-existent position in reality) with the elbow pointed straight back

in line with their shoulders and the racket pointing down to the ground behind their back.

They start with their weight back and then toss the ball as they bring their weight

forward. Remember this is a drill regardless of whether the person starts with their

weight forward (Smith, Stich) or back (Sampras). And the forward weight transfer is the

lynchpin that holds the rhythm of the service toss together. I have the student reach up

on the windscreen (stay away from the poles) to the contact point for the serve. They

shoudl be reaching up and they should see the back of their hand (eyes up). The racket

face is, of course, parallel to the fence, perpendicular to the intended path of the ball.

From here they first move ONLY the wrist as they cock the wrist back, keeping the shaft of

the racket in that plane I talked about. Next they bend the elbow to drop the racket down,

but with the shaft still in that plane. Then they turn the shoulder back to the

backscratch. It's 3 steps backward and then reverse 3 steps upward to get the sense of

what the racket will do. Next place the racket back in that backscratch position. Don't

try to do the whole serve from the beginning of your service motion. You must toss the

ball straight up next to the fence and then swing up and trap the ball on the windscreen.

If you do it right and swing the racket up to the ball, you can swing up without hurting

your fingers or hand. When you get the hang of it, you can actually bang up pretty hard at

the windscreen (some clubs get touchy, but you won't hurt the fence or the

windscreen...it's just a little loud)

Swinging the racket head up to the ball is a critical part of what is going on here.

Bottle, the windscreen will be a lot more forgiving than that pane of glass. Don't get so

wrapped up with the angle. Brian is giving you some great information, but your body

doesn't really understand the difference between 55 and 45 degrees. Find something you can

feel and go from there. When you can make that fence "pop", you'll have a good start

toward a service snap which obviously requires your wrist to move through the ball. But if

you don't understand hitting up, you haven't got a chance!

Curious to hear what you guys think
don

[airforce1]

position

I think it's clear that to maximize the racket head speed, you need to first be in position to do it. From there it's up to potential and training to get the most out of that position. So to answer Bottle's question of how to do, the answer is to get in the best position to let the body do what it can and have to have the right explosive idea in mind during the action. I'm going to start a new thread for those who might be interested discussing this positioning.
thanks,

[julian]

new thread?

I think it's clear that to maximize the racket head speed, you need to first be in position to do it. From there it's up to potential and training to get the most out of that position. So to answer Bottle's question of how to do, the answer is to get in the best position to let the body do what it can and have to have the right explosive idea in mind during the action. I'm going to start a new thread for those who might be interested discussing this positioning.
thanks,

Where is the new thread?

[julian]

a relation between the video and your drill ??

This is a great thread. A lot of deep thought backed up by some good evidence in high

speed video right here and in the shots that John forst got a couple of years ago of that

extreme supination on Roddick's serve. I was at the USPTA meeting in La Quinta when John

first unveiled that video and he was talking about guys getting additional mph with that

extreme (and a little scary) motion.

But Bottle has a good point. How do you do it? All the anatomical and biomechanical

analysis does not necessarily translate to helping the local hacker or anyone challenged to

get a great snap to achieve that goal.

It's good to analyze someone's motion and see that certain things might be missing and have

to be added, but technical terms don't translate to performance on the court.

So,...
a serve is like the snap of a towel when you make it "pop";
a serve is like the last person on the end of the "Whip" in a string of ice skaters;
a serve is like the last part of a golf swing when the club explodes into the ball at the

last minute.

That towel pops because the last little bit of the towel is going so fast trying to catch

up. All that energy gets to the end of the towel and has nowhere to go.

That person at the end of the "Whip" on the ice is going very fast even though the person

in the middle is hardly moving at all.

In a lot of slow motion video that you can see of golf pros, the last second snap of the

wrists is almost incomprehensible to most of us mere mortals. The position is almost

painful, but clearly they are doing something different and a lot of it is that last minute

snap right before and through impact.

A lot of it is related to the physics of tangential forces generated by

centripetal/centrifugal forces (I don't remember). Something like the tangential force is

proportional to the velocity squared (Brian, help me out here). You are trying to generate

a force upward through your arm all the way from your toes and redirect it perpendicular to

the direction you are actually throwing the racket (straight up). Since you are holding on

to the racket it can't go up and instead the force gets directed on the tangent off the

face of the racket into the ball. When you catch the ball cleanly on the right spot, it

really pops. It's one of the toughest things to get students (and I mean nationally ranked

juniors as well) to do consistently, is to hit that ball cleanly and not slide under or

around it (and I don't mean only flat serves).

If you are trying to reproduce this motion, recognize that the racket shaft is moving

toward the ball in a plane that includes the contact point and the target. That's

necessary to get an efficient transfer of momentum and power to the ball. But even as the

shaft is staying in that plane, the racket face is turning as shown here to a position

perpendicular to that plane.

I line my students up next to a fence with a windscreen (need a 10' fence). They take a

position about 18" from the fence to the front foot or shoulder. There isn't room to take

the initial position so I have them take the backswing first and stop with the racket in

the backscratch (a non-existent position in reality) with the elbow pointed straight back

in line with their shoulders and the racket pointing down to the ground behind their back.

They start with their weight back and then toss the ball as they bring their weight

forward. Remember this is a drill regardless of whether the person starts with their

weight forward (Smith, Stich) or back (Sampras). And the forward weight transfer is the

lynchpin that holds the rhythm of the service toss together. I have the student reach up

on the windscreen (stay away from the poles) to the contact point for the serve. They

shoudl be reaching up and they should see the back of their hand (eyes up). The racket

face is, of course, parallel to the fence, perpendicular to the intended path of the ball.

From here they first move ONLY the wrist as they cock the wrist back, keeping the shaft of

the racket in that plane I talked about. Next they bend the elbow to drop the racket down,

but with the shaft still in that plane. Then they turn the shoulder back to the

backscratch. It's 3 steps backward and then reverse 3 steps upward to get the sense of

what the racket will do. Next place the racket back in that backscratch position. Don't

try to do the whole serve from the beginning of your service motion. You must toss the

ball straight up next to the fence and then swing up and trap the ball on the windscreen.

If you do it right and swing the racket up to the ball, you can swing up without hurting

your fingers or hand. When you get the hang of it, you can actually bang up pretty hard at

the windscreen (some clubs get touchy, but you won't hurt the fence or the

windscreen...it's just a little loud)

Swinging the racket head up to the ball is a critical part of what is going on here.

Bottle, the windscreen will be a lot more forgiving than that pane of glass. Don't get so

wrapped up with the angle. Brian is giving you some great information, but your body

doesn't really understand the difference between 55 and 45 degrees. Find something you can

feel and go from there. When you can make that fence "pop", you'll have a good start

toward a service snap which obviously requires your wrist to move through the ball. But if

you don't understand hitting up, you haven't got a chance!

Curious to hear what you guys think
don

Which part of the video your drill would reproduce?

[bottle]

In Words, the two Moving Images

I see the delayed elbow along with pre-loaded upper arm finally rising, forcibly, from behind the body, which was 30 degrees back and now is 30 degrees to the side, to ahead of and above it, with forearm winding (cocking) an extra amount at the same time.

I see the elbow stopping, thus shooting the passive arm until it is almost straight.

I see the triceps violently firing the arm straight at which point the wrist violently straightens reinforced by simultaneous, violent shoulder rotors release, which has delayed and built itself all the way to this high time and place-- all of the foregoing done with a light arm.

Finally, almost after contact though that's a physical impossibility, the forearm twists for position (the high five) and both it and the whole arm continue their joint twist into the still high downward pointing immediate followthrough.

Allen Fox in "Think to Win," 1993, writes: "The final element in generating power on the serve is the wrist snap. This occurs after the racket has been flung out from behind the neck by the shoulders, legs, and torso. The wrist is the final accelerator and simply adds its velocity to those already provided by the other sources."

Um, there is a need for great humility in all such courageous, attempted verbalizations-- Don's, Allen Fox's, Presidential Airplane's, mine, anyone's--
also for great, though critical, restraint and sympathy in judging them.

"You're either wrong or partially right." -- Craig Mello, Nobel Laureate in Medicine talking about science.

But what will Brian Gordon say in next month's article? To hold the mayo, I mean the violent triceps extension and violently fire the rotors right then instead?--I didn't even think of that. Who knows? For sure, mystery is nice and absolutely necessary for consistently transcendent serves.

NOTE: I got the adverb "violently" to describe final wrist motion from Allen Fox's book, where he also shrinks the usual importance ascribed to "pronation." Pronation is there-- photographically, Fox demonstrates it as coming after the wrist snap and mostly after contact. Fox's emphasis reminds me of Mark Papas at the "Revolutionary Tennis" website urging people to serve with "cojones."

P.S. Since elbow lift, elbow straightening, and wrist straightening are THE MORE MAJOR CONTRIBUTORS (See Brian Gordon) but also form a rippling kind of sequence, I see the server on a given day living by verbal cue as THINKING EXCLUSIVELY ABOUT THEM.

[airforce1]

julian,
did you see the other thread on the "upward serve positioning" motion which also contains videos that illustrate the point about uncoiling prematurely?

[julian]

your thread

julian,
did you see the other thread on the "upward serve positioning" motion which also contains videos that illustrate the point about uncoiling prematurely?

I cannot find it-maybe u can send the content
to juliantennis@comcast.net