Article on Roddick Serve.... Supination

[gzhpcu]

John,
You mention in your article that when the racket drops down behind Roddick's back, he also supinates his forearm as something particular to his movement This contributes to racket speed since the range of pronation increases, but is this not to be expected if you are attempting to "scratch a friend's back"?

[johnyandell]

I would expect it! I've just never seen it to the extent Andy does it.

[gzhpcu]

Could it be that he is biomechanically more flexible in this area? More than others?

[johnyandell]

Good question. I don't know. It seems to require his abbreviated motion so I think that is a factor.

[gzhpcu]

Maybe his abbreviated motion which keeps his racket farther out to the right during the initial phase, and pointed forward, allows more of a whip-like swing combined with scratching a friends back? Similarity in whip-like motion to the modern forehand where the racket head points forward and starts the loop backwards quickly only when the ball bounces in front of the player?

[gzhpcu]

P.S., I like the supination comment you made John. I have tried it out and feel it really helps keeping the racket farther away from the back at the bottom of the loop.

[johnyandell]

Some players have been able to feel that and others not--the "nots" including one player I know who has been in the top hundred and who can serve 130mph (and get it in...) I think this is something quite advanced and physically possible only for certain players. But if you try it out and like it without destroying any other elements in the motion, then I don't see what's bad about that.

[vmiller]

Hey John,

Do you have any players in mind besides Roddick that do this more than what's typical? I have an idea and I want to see if it holds.

[johnyandell]

Not that I've noticed in our film to near the extent of Andy. What do you see?

[vmiller]

What do you see?

In my opinion, as different as Andy's and Pete's motions are, they have something in common during their drop that is not overly common. As you can see in the picture, there elbows remain close to a 90 degree angle, the racket basically comes straight down, and it's farther away from their body as a result.

Now look at Nalbandian. He severely closes his elbow causing the racquet to make a circular path behind his back and the racquet also stays closer to his body.

I've wondered if there's any meaning behind this for a long time. What I've come up with is that Andy and Pete's drop is more efficient in terms of transfer from torso rotation to internal shoulder rotation. As Bruce Elliot describes, the leg drive and torso rotation help to stretch the shoulder in the direction of external rotation during the drop, which is a big source of racquet speed. It seems that it would be a more efficient transfer if the racquet drops straight down like Andy and Pete rather than in a circular pattern like Nalbandian.

If you don't think I'm crazy yet, you're probably wondering what this has to do with Andy's supination. The Andy/Pete drop seems to be conducive to external rotation where the Nalbandian drop seems to work against it by bringing the elbow forward. External rotation and supination work together like internal rotation and pronation. So maybe there's more to Andy's unique racquet movement than just supination. Maybe it's the combination of the additional external rotation he gets from his style of drop and his supination during the drop that give him a larger range of motion for internal rotation.

I know it's a bit off this topic, but another problem I see with the Nalbandian like drop is that it can cause the elbow to come forward too early which I think weakens or breaks the link between the torso and shoulder that drives internal rotation. That's at least what I've found with my serve.

What do you think?

[johnyandell]

Vin you may or may not be crazy but that is an interesting observation. Nalbandian definitely bends his elbow more and this changes the racket path for sure. It's a little clearer from the rear so look at these two movies. The only question is what is the effect on the rest of the motion. David is definitely a lot more open a lot sooner and it could be related. BUT the pinpoint stance has something to do with this too. Why don't you see if you can find anymore examples of players with more elbow bend?

[vmiller]

I'm glad this caught your interest. I'll work on a list of players tonight when I'm able to look at some video. Off the top of my head, I know that Guga does the circle drop like Nalbandian, and most players are in between the extremes of Nalbandian and Roddick/Sampras.

The only question is what is the effect on the rest of the motion.

I think the circular loop does not facilitate external rotation during the drop as well as the Andy/Pete drop does. If this is true, less external rotation is obviously going to result in less internal rotation, which means less racket speed.

Here's what I think are a few convincing arguments that support the Andy/Pete drop.

1. More External Rotation - The hand and racket are further away from the humerus during the Andy/Pete drop. Gravity applied to the weight of the racket and hand during the drop is most of what externally rotates the humerus. Mathematically, this force being further from the humerus, which is the axis of rotation, will produce more torque. More torque on the humerus is more external rotation.

2. Better Transfer Across the Shoulder - The ~90 degree angle of the elbow in the Andy/Pete drop also results in the hand and racket being further away from the shoulder joint. Because of this, the transverse abduction (elbow pinned back) achieved during the backswing, or more importantly, the stretch across the front of the shoulder that it creates, is easier to maintain. The more intact this stretch remains, the more force that can be transfered from the torso to external rotation and it's rebound into internal rotation.

I'm not certain of the physiology behind this, but I think it's because the biceps must be somewhat contracted for the elbow to be closed. The biceps being contracted will reduce the range of motion of the shoulder making it more difficult to keep the shoulder stretched.

And here are some other supporting ideas.

3. Quicker Arm Extension - A more closed elbow angle means that it will take longer to fully extend the arm before contact. Maybe this complicates timing? Since the arm has to be fully extended for internal rotation to translate into forearm pronation, maybe the added timing challenge could have an effect on pronation. Obviously pronation can occur independently of internal rotation, but it will be stronger if it's driven by internal rotation.

4. Racket Trajectory - The closed elbow angle results in the racket being closer to the body during the drop. This can cause the racket path from drop to contact to be more vertical than if the racket were further away from the body at the bottom of the drop. I would think that as the vertical component increases, ball velocity decreases. And we can all see from Pete that you don't really need to drastically increase the vertical component for spin.

For what it's worth, I've been able to apply this drop concept to my serve with good results. It's even changed the way I think about producing spin.

Sorry for being so verbose.

[johnyandell]

Yeah there are a few words here...all that physiology frightens me and confuses me but is it true???? It might very well be.

I'm bailing out on this one and asking Brian Gordon what he thinks. Brian are you out there??

[vmiller]

all that physiology frightens me and confuses me
...
I'm bailing out on this one

I'm sorry. I didn't think it was that bad. I thought it would be helpful to have some objective arguments. I'd still like to hear your opinion, scientific or not, so hopefully you won't bail.

Here's the list you asked for. It's such a mixed list that I really don't know what to make of it. One thing that I noticed is that there seems to be more elbow closing among the women. There's also a lot of variation in wrist position which complicates the issue further.

Another thing thing that varies is the timing of the elbow close. The players that close earlier seem to have less of a loopy drop than those that close later.

Since you mentioned it, I included each players stance.

Closed Elbow Drop
Carlos Moya (pinpoint)
Tim Henman (platform)
Greg Rusedski (pinpoint)
Tommy Robredo (pinpoint)
Goran Ivanisevic (pinpoint)
Pat Rafter (pinpoint)
Gustavo Kuerten (pinpoint)

Martina Hingis (pinpoint)
Monica Seles (pinpoint)
Venus Williams (pinpoint)
Lindsay Davenport (pinpoint)
Jennifer Capriati (pinpoint)

Open Elbow Drop
Wayne Arthurs (pinpoint)
Mark Phillipousis (pinpoint)
Xavier Mallisse (pinpoint)
Marat Safin (pinpoint)
J.C. Ferrero (pinpoint)
Paradorn Srichaphan (pinpoint)

Amelie Mauresmo (platform)

[johnyandell]

Interesting lists! Don't get me wrong. All I am saying is that I want to get some input from someone who understands the physiology better than me--that's Brian.

Honestly I'm not sure what my opinion is. The open question is whether that difference in the angle of the elobw actually effects anything. Is it just style or something more fundamental. I'm not going to try to bs anyone even on my own site about stuff that I'm not certain about myself. But I will continue to think about it and hopefully we'll eventually hear from Brian.