Wrist movement

[mntlblok]

It looks like five files is the maximum for uploading attachments, so I'll try to remember to post the photos for "extension" and "flexion" in another post.

Actually, I think I'll just do it now and add the comments to that post - cause I'm getting old and tend to forget such things.

Kevin

[mntlblok]

More photos

See the previous post for the other photos. . .

I'm new to the forum, but I'm like a pig in slop. I've read tons of great stuff here the past couple of days and just love it. As a practicing anal retentive, it doesn't get any better than this. :-)

The following refers to the right arm, and the photos are of an Eastern forehand grip as "neutral", with the long axis of the racquet parallel to the floor and the butt of the racquet grip facing the wall behind.

It does strike me that some additional clarity might be possible if some of the terminology were standardized. In the area of wrist movement, I believe there are three basic planes that the wrist moves in. I guess you could find some more dimensions with string theory (I use 15 gauge), but I'll never understand that stuff.

In reading some of John's posts on ground strokes, when he is referring to "rotation", I believe that is called "pronation". Pronation just means "palm down". In the palm down position, the ulna bone of the forearm is to the right (looking down at your own forearm) and the radius bone of the forearm is to the left. Supination is just the opposite. Both place the racquet in a horizontal plane, parallel to the floor.

In the neutral position, the radius is on top. The radius is on the "thumb" side of the wrist.

Thus, "radial deviation" means that the racquet is pointed upwards from the neutral position towards the thumb. The top and bottom of the racquet frame remain in the vertical plane. "Ulnar deviation" is the opposite.

Finally, "extension", I believe, is what John refers to as having the wrist "laid back". This occurs when one turns the racquet face to the right from the neutral position. "Flexion" is just the opposite. These moves leave the racquet frame in a vertical plane.

I'm hopeful that these terms will help with discussion clarity rather than obfuscate. If I have any of this stuff wrong, please straighten me out. I *really* look forward to discussions involving these terms. :-)

Kevin

[lukman41985]

mntlblok,
Thank you so much for posting the pictures. I think they definitely will form the basis of our arguments here about what's going on in during the stroke.

[mntlblok]

Other joints

As I continue to study what's going on during the strokes with these cool videos and realize how complicated it is, it strikes me that it probably makes sense to point out that the racquet face can move in all three of those ways by just having movement in the shoulder, and (I think) move in two of those planes just by movement in the elbow joint (no pronation or supination via the elbow). Again, correct me if I'm wrong.

Throw in the ability to have movement about the axes of the spine, waist, knees, ankle, and toes, and what is causing the change in racquet face orientation gets very complicated. Looking forward to the 3-D studies.

Kevin

[GregRyan]

Anatomical terminology

I think Kevin said it best when he stated that human movement is complicated. I also agree that this language must be consistent so that we all know what we are discussing. I feel the only way to do this is to use the anatomically correct terminology. Tennisplayer will address these questions in detail in a future article.

The movement of the wrist:

The wrist is a ellipsoidal bi-axial joint. This means it can only move in two planes; Flexion/Extension in the sagittal plane and unlar/radial deviation in the frontal plane. The action of pronation and supination occurs at the radial-ulnar joint which rotates the forearm.

A lot of confusion arises when this terminology is used for both action/movements and positions. It is possible for the movement of the forearm to be pronation and be in a supinated position at the same moment.


To the reference of John's articles:

A laid back wrist is a wrist that is in a extended POSITION.

I think (only John can answer this) when John discussed arm "rotations" he is referring to long axis rotations of the forearm and shoulder joints. In the Nadal forehand it is impossible to see what movement (forearm pronation, shoulder internal rotation or both) is causing the racquet face to close when the elbow is fully extended (straight arm). Only a 3D analysis can determine the mechanics of this movement.

I look foreword to hopefully conducting this study in the future.

Let’s keep up the dialogue

Greg Ryan

[mntlblok]

Radial-ulnar joint

Thanks for that explanation, Greg. Where is the radial-ulnar joint - near the elbow or near the wrist? A quick Google image search turned up a "distal" radial-ulnar joint, suggesting that maybe there is also a "proximal" radial-ulnar joint up around the elbow. My anatomy course ended at the antecubital fossa on the upper extremity. :-)

The primary picture that made me start to re-think what is going on with pronation was that of Roddick hitting a topspin forehand.

I picked something up last summer watching the super slow motion replays on TV during Grand Slam events, and was pretty sure that I had figured out *the* answer to hitting topspin forehands. I noticed that on each of the few forehands that I had seen in those replays that the players had all, just as (or before) starting the forward swing, suddenly and very quickly, sent the butt of the racquet to the right - some almost all the way to the right sideline (all righties).

I have since, on this web site, had the mind boggling experience of witnessing the same move by the lefty Nadal. The rapidity with which he goes from having the butt of the racquet facing the opponent's backhand corner to the left sideline, and then back to the right sideline at impact is just amazing to me. Of the forehands that I looked at so far, only Roddick has anything comparable.

Federer seems to have a distinctive move in that direction, too. His doesn't strike me as being as "violent" as Nadal's or Roddick's. As a matter of fact, it seems to be a very controlled, yet, to me, an intentional move.

Even Agassi, he of the "no wrist" strokes, seems to have a bit of that same move (I think more so on the backhand). My theory was that this move was what allowed the professionals to hit their forehands so consistently and why they could generate such fabulous racquet head speed and why I couldn't.

Then, I looked at that same area of Hewitt's and Blake's forehands. Hmmm. Both seem to only barely get the butt of their racquets beyond pointing at the net before starting to square it up at impact. And Blake, to me, has one of the hardest forehands around. I remember being amazed by it a couple of summers ago against Agassi (Washington, maybe?).

The other aspect of my theory was that these sudden moves were made by a sudden "ulnar deviation", and that in the forward swing, the unleashing of this move was what led to the massive topspin and racquet head speed that they could generate.

Reading this dern web site (which I've done a ridiculous amount of since joining last week) has forced me to re-evaluate. One of the reasons that I was sure that ulnar deviation was going on was that the plane of the racquet face didn't seem to change as the racquet came forward towards impact. My first reading of the "wind shield wiper" *after* impact being a "rolling over" (or maybe "turning over") made me think that John was confusing the "radial deviation" move (in my mind) with pronation.

The other thing that made me conclude that it wasn't ulnar deviation was the fact that the face of the racquet would not remain parallel with (or to) that move unless the player had an Eastern grip. The guys who seemed to do it to the most extreme seemed to be the guys with the more extreme grips. Ulnar deviation with a Western grip - well, it's hard to even think about. :-)

But, as I looked over and over at Roddick's follow through (and, I believe, the forward swing leading up to impact) I concluded that it was, indeed, a pronation going on. But, I kept stumbling over the fact that the plane of the racquet face wasn't changing (relative to the ground) - which I felt must happen if the wrist (forearm) was turning over in pronation. [Now, I find out that it's not the wrist that pronates, (at least as I had tried to show in the photos), but the radial-ulnar joint that allows pronation]. No big deal, as the result would still be the same - the racquet face angle would have to change relative to the ground if the radial-ulnar joint was turning over in a counterclockwise manner - looking out towards your hand. :-)

What I think I now see is that this pronation is happening from the shoulder joint. Since then, I think I have picked up the same thing in one of Agassi's forehands on the site. In particular, it was on a "high" ball - as was the Roddick foreand that I had been studying. Both of them had the racquet head well below the hand at the end of the backswing, but the racquet head was well *above* the hand at impact - and I think they got there from a "shoulder" joint move. I'll have to leave it to Greg to describe what combinations of planes that that might be happening in - sagittal, transverse, etc. :-)

I hope I'm not boring you folks to death with this, but I also think I may be picking up some "flexion" of the wrist in some of the topspin forehand forward swings before impact. I was convinced, even before finding this site, that none of the professionals ever did this. And, I would have guessed that Agassi would have been the last to suspect of this. I'm still holding out hope that I'm wrong on this one. But, in one of the super slow-mo's on the site, on the frame just after impact, his wrist is *more* laid back, or in further extension than in the last frame just *before* impact. *If* he is going into some flexion prior to impact, but the force of the impact of the ball on the racquet temporarily lays his wrist back further into extension, then it would *look like* he hadn't made any move toward flexion prior to impact for some number of slow-mo frames after impact. I would note that in one of the network slow mo's, I swear I saw a racquet face stop and go backwards for a frame or two after impact before starting forward again. I believe they say that that does happen in "The Physics and Technology of Tennis".

I wouldn't have even looked for this sort of thing except for what I think I saw in one of the frame by frame looks at Maria Sharapova. I *think* I saw it in one of the "Your Stroke" entries. If she doesn't move a *bunch* from wrist extension to wrist flexion before impact on her forehand, I'll eat my hat. (I just saw Sandra Bullock make the same move (pitifully) in "Two Weeks Notice"). :-)

However, it has only taken me a few days to become absolutely convinced that arm joints aren't where my problems lie with my topspin forehand. You don't have to look at the lineup of all those players at the end of their backswings in their unit turn position with their left arms pointing to the right, looking at the oncoming ball from over their left shoulders for very long to realize that maybe that is something one might ought to be doing, as well. I had been meaning to get around to that aspect of my stroke some day - as soon as I got the wrist figured out. :-)

I'll be sending in a video of my pitiful stroke as soon as my new miniDV video camera gets here. I now see that you can get a TroubleShooter 250 that will do up to 1000 frames per second for only $5900. It's looking like it may take more nagging than I'm capable of to convince my wife that we have to have one. :-) Anybody know of a tennis camp in the southeast that uses high speed video? Maybe I can talk my club into buying one.

I truly hope that I haven't driven too many people nuts with this stuff. I know how it turns most people off when I try to do all this analyzing, but I'm hoping that that sort of thing is what this site is all about. I see there's a caution sign that I can tag this with. :-)

But, don't get me started on my recent observations about topspin backhands, slice shots, and volleys. :-) I gotta go work on my new kinetic image for my forehand. . .

Kevin Bryant
Savannah
Merry Christmas

[johnyandell]

What you should do is attach a URL of a stroke and count the frames when what you are talking about occurs.

To be honest, I can't follow what you ahve written on the verbal explanation--and there is no need for it to be soley verbal. Just past the URL into the thread.

I think that there is one ver important question to consider when you try to understand what happens inch by inch in any stroke.

Am I seeing a "cause" or an "effect"? It's similar to the issue with the wrap if you check out that article in Myth part of Advanced Tennis.

I have seen players cause themselves tremendous difficulty trying to manually replicate certain moves or positions that occur naturally as a result of other moves and positions...

This is where the terminology problem can actually add more confusion.

Making a huge jump in your forehand does not require discovering the holy grail of complete quantitative and descriptive analysis.

[mntlblok]

URL's

[QUOTE=johnyandell]What you should do is attach a URL of a stroke and count the frames when what you are talking about occurs.

To be honest, I can't follow what you ahve written on the verbal explanation--and there is no need for it to be soley verbal. Just past the URL into the thread.]

I never thought of pasting the URL. I didn't realize that would work. I'll give it a try. I wonder if "screen captures" will work? Maybe I'll experiment with that. I'll see if I can do it with Sharapova's forehand.

I was primarily just trying to get my thoughts down in writing in that post. I know that it will take a lot of further clarification, even with photos, to make myself understood. I think it is just the nature of the beast that something this complicated is difficult to make clear - regardless of the terminology used.

My office computer doesn't play very nice with Quicktime, and I'll be out of town for a few days after today, so it will be a bit before I can start doing all that I would like with the videos.

I've gone through the "Your Strokes" again, and it doesn't look like any of the videos that I mentioned were in those. I'm now thinking that they must have mostly come from the "High Speed Archives". Yes, I find Sharapova's forehand there.

I "uploaded" a couple of "gifs" that I made from screen captures of Sharapova's forehand, but as I "preview" the post, it looks like they're not making it into the post. Maybe they just don't show up in the preview. I'll post and see. The first is when her foreward swing starts and it appears that the angle between her forearm and racquet is 90 degrees or less and the second is just before impact with the ball and that angle seems to be much greater than 90 degrees.

As to the "holy grail", I agree with you completely. I was attempting to make fun of myself for looking for the answers in the wrong places. I'm convinced that if I learn the "unit turn" and the "hitting arm position" at impact that my forehand problems will become greatly simplified.

That doesn't mean that I don't find it extremely fascinating to magically see what is happening in super slow motion and try to see if some conclusions can be drawn from the analysis of it. Seeing, for example, what you were able to divine from videos about the changes in McEnroe's service motion is one of the coolest things I've ever seen.

Kevin

[mntlblok]

Sharapova Myth of Wrist Exception?

Went home for lunch, tried that computer, and found that if I reduce the size of the GIF enough that it looks like it will allow the attachment. Couldn't get the URL to upload via the "browse" window, but here it is:

http://www.tennisplayer.net/members/strokearchive/high_speed/High_Speed.html?MariaSharapovaForehand.mov

It also looks (to me) like Sharapova has less of a low-to-high move with her racquet head.

While it still sorta looks (to me) like Andre may be doing a little bit of the same thing, it's not clear enough from that view angle in the High Speed Archives to draw any conclusions. It sure looks like Maria is "flexing" her wrist well before contact, though.

Kevin

[GregRyan]

Radial-ulnar joint

Great observations Kevin, I appreciate the passion for analysis.

There is a proximal radial-ulnar joint close to the elbow and a distal radial-ulnar joint close to the wrist. They are both pivot joints with one degree of freedom (movement in one plane:transverse). Both of the joints articulate at the same time during movement.

I think many of your observations are correct. The difficulty in the analysis is when the movements are happening, in what sequence and through how much range of motion. I always come back to the complex nature of movement. Tennis is an extremely dynamic sport. It is an open skill where the environment (ball) is moving under many different conditions (speed, spin, depth, height, and trajectory). The player adjusts to these conditions and also has a goal in mind in terms of the shot they are hitting (offensive, defensive, or neutralizing). In performing the shot they manipulate the speed, spin and trajectory of the ball. When you consider all of these variables there can not be one solution to the movement pattern. This is why we see a variety of movement patterns in each individual player (the 27 variations of Federer’s forehand). During the swing of the forehand there is some combination of horizontal flex/ext at the shoulder, int/ext rotation at the shoulder, abd/add at the shoulder, flex/ext at the elbow, pronation/supination, unlar-radial deviation, and flex/ext at the wrist. Players are using all of their available degrees of freedom in some capacity. I will refer to John’s “holly grail” in trying to figure out the speed, range of motion, and sequence of the movement for the type of shot being hit. There is a famous Russian neuroscientist, Nicolai Bernstein who has published groundbreaking articles on motor control. You might be interested in reading his translated works; he was way ahead of his time.

I agree with the wrist analysis in the Sharapova clip, but the camera angle makes it very difficult to see the relationship between the wrist and the forearm. It looks like she is hitting a hard flat shot of off a high ball (the ball is coming off with a high sidespin component). Does the wrist movement have something to do with that or does the movement occur on all of her forehands?

Can’t wait for the next post

Greg

[johnyandell]

My suggestion is that you go to the Advanced Tennis section and read the article on commonalities across the grip styles, especially page 3.

Also the Myth of the Wrist Forehand in the same section.

I'm not sure Maria Sharapova is the example we would pick to try to generalize about wrist movement.

The wrist is the last link in the chain and what happens there is the consequence, in part, of a long sequence of events. Before you talk about that element, what about the positions that precede it?

If anything you might say that Sharapova, great as she is, doesn't extend nearly as well on her forehand as other top players, men or women. I know a little about this because I filmed her at age 11 working with Robert Lansdorp.

As I know my fellow editor Greg Ryan agrees, the wrist release is a natural consequence of the swing. In the Common Elements article you will see Hewitt's wrist actually move back after contact--infrequent but you do see it.

The wrist is more or less along for the ride--but for most top players most of the time it stays laid back until well after the hit.

It's like the questions Vin Miller used to mail me about wrist on the serve. When we saw the video of his motion we discovered some other fundamental issues that were the key to him making real improvement.

[mntlblok]

Service return

http://www.tennisplayer.net/members/famouscoach/brett_hobden/what_is_the_modern_forehand/what_is_the_modern_forehand.html

Brett Hobden's above article on "What is the Modern Forehand" under "Type of Ball Received" shows Agassi's and Federer's forehand strokes on returns of fast serves. I've often heard that one must "shorten" his stroke on service returns, but this is my first good look at what might be involved in that action.

I've attached a frame of Agassi with the butt of his racquet somewhat out to the his right just before starting forward in a full swing. It's interesting to note that neither he nor Roger reach this "butt to the right" position in those service return segments, but both do it to some degree in their full swings. I find that it doesn't show up all that well in freeze frame shots from the High Speed Video Archive as it does in viewing it in slow motion.

I've also attached frames of Roddick's forehand from the High Speed Video Archive, which I believe illustrates my "butt pointing" concept pretty well. The first shot is when the butt of his racket is still pointing to his left, and the second is 19 frames later, just as he starts forward with the butt of his racquet well out to the right. It ain't long from that point before his racquet has moved almost 180 degrees to make contact with the ball 8 frames later.

Kevin

[GregRyan]

What does the butt tell us?

I am not sure what the point is about the movement of the butt of the racquet?

Take a backswing until the shoulders are perpendicular to the net and the butt of the racquet is pointing to the net. Then just rotate your shoulders about 75 degrees without moving ANY other joint. The butt ends up pointing to the left with the racquet parallel to the net. This does not happen, but it is possible. The point is that the butt of the racquet tells us nothing about the movements of the body. It only tells us about the movement of the racquet.

GR



Kevin,

Here is an article explaining Bernstein's concepts on the complexity of human movement.

http://www-anw.cs.umass.edu/~mtr/papers/VanEmmerikR04.pdf#search='bernstein%20russian%20sc ientist%20motor%20control'

[mntlblok]

Butt

I'm off for a long weekend, but would just say that I'm generally in agreement with you guys.

My point about the butt of the racquet is that the more rotation of the racquet in those last few ms's, the faster the racquet head is going to be moving - and while I've heard of pointing the butt of the racquet towards the net in the backswing, I'd never heard of anyone pointing it to the total opposite direction that it would point a few microseconds later at ball contact (or heard anyone recommend it as a means for more racquet head speed). BTW, I find it a painful position to get to and stay at for long - especially if you forgot your unit turn. :-)

I guess I'm just wondering if that is something to shoot for when you want to really crank one up - or whether mortals should even try it. I suspect not. But, I'm still gonna play with it when my new camera gets here. :-)

And, yes, I can definitely see that that move could be solely the *result* of things that have previously happened in the swing - but what all do Roger and Andre do to keep it from happening at all on those service returns>

Happy Holidays.

Kevin

[johnyandell]

Kevin,

Again you are focusing on one tree that didn't produce the forrest. I see that you want to understand all the details of the strokes. But controlling where the butt of the racket points for a few milliseconds is not going to be a productive strategy--in fact definitely the opposite.

I'm not going to reproduce several years of work in one Forum post to try to convince you of the relative nature of some of these details. If you read the suggested articles carefully, then you will be more up to speed to discuss this--what you'll see is that if the players make certain common positions that's the key--not necessarily the complex and dynamic (to use Greg's terms) micro movements of the frame by frame patterns.

John