Serve Question for Doug

[tennis_chiro]

Right on point in your thread above

Another Factor:

The foot back style is also associated with a different pattern of torso rotation. Federer, and in the more extreme case, Sampras turn away from the ball when the weight is dropped roughly evenly at the deepest point. The turn back into the shot also results in a closed torso angle to the baseline at contact. This is associated with a left ball position inside the racket hand.

Compare that to the women who are often wide open at contact with the ball position further right.

Jim Fawcette's picture in #1274 above is right on point

http://www.tennisplayer.net/bulletin/showthread.php?p=20934#post20934

The actual right shoulder extension vs the line of the shoulders is minimal.

don

[bman]

I know you put a lot of effort into that response and thanks for being thorough, but when I look at the Isner's first serve in that tennis resources video you linked to, he is not pushing up with the back leg. He does push down, but when its time to go up the back leg is already off the ground and the left leg is doing the entire upward thrust.

[julian1]

Your response NOT clear

I know you put a lot of effort into that response and thanks for being thorough, but when I look at the Isner's first serve in that tennis resources video you linked to, he is not pushing up with the back leg. He does push down, but when its time to go up the back leg is already off the ground and the left leg is doing the entire upward thrust.

Are you replying to Doug Eng or tennis_chiro?

[tennis_chiro]

It's Doug's post #10 in this thread

Are you replying to Doug Eng or tennis_chiro?

See post #10 in this thread from Doug.

don

[don_budge]

Both Legs...?

P.S. Here was the view from the nose bleed seats

[IMG]
Roger Federer Quarters BNP13 ©jfawcette 49 by james.fawcette, on Flickr[/IMG]

Beautiful picture! It looks as if he is going to use both of his legs...

[DougEng]

I know you put a lot of effort into that response and thanks for being thorough, but when I look at the Isner's first serve in that tennis resources video you linked to, he is not pushing up with the back leg. He does push down, but when its time to go up the back leg is already off the ground and the left leg is doing the entire upward thrust.

Good points.

The push-down is the primary initiating force. Much like the forehand groundstroke in the unit turn and loading. The back foot provides the starting forces. It's kinetic chain principles. Even if the player steps in on the forehand groundstroke.

Again, I would want to point out this isn't a debate whether the front leg is involved but what is given by the top of the field in serving biomechanics from efficiency and injury position. The use of the back leg is considered essential and often deficient in foot-up serves. Being deficient does not necessarily make the serve not a weapon.

Case in point, as there are technical weaknesses in Venus Williams serve, it's still a big serve in most part as her arm motion is excellent and she's 6'1". The leg deficiency leads to some weaknesses in the core and shoulders, hence as John Yandell points out, she opens up.

John Isner is sufficient in the back leg but he probably could use it more. Which is probably why biomechanists don't consider his serve ideal to copy (consider what if he was only 6'0"...how effective might his serve be? I think he may top out at 130 or 5-8 mph less than optimal...I would consider 135-140 in the range of optimal serves for 6'0 or 6'1"). In his case, his height provides an unusual advantage where he doesn't need the same upwards force as most other players. This doesn't mean the front leg is not doing work.
The same for his groundstrokes, massive due to his natural leverage but do we consider it ideal? Compare his motion to a major league baseball pitcher. Tim Lincecum: http://www.youtube.com/watch?v=lGDlwhITEp8

Although a baseball pitcher isn't throwing upwards as in the tennis serve, the mechanics can be quite similar in terms of leg drive. In this case, Lincecum drops the hand low during the back leg drive (seen best maybe at 2:26) which keeps the weight on the back leg and rotates away from the direction of the pitch.

And the case of Federer is the same, utilizing both legs. But from a biomechanic stand point, the use of the back leg is considered an initiator of forces, which does not eliminate the use of the front leg. In fact, Ellenbecker and Kovacs suggested the front leg is involved in greater knee flexion which is what we are seeing.

However, try standing on the front leg and see if the cartwheel effect is greater or lesser, standing on that leg. Compare to using both legs. Or compare to using back to front leg (as in the Kovacs video exercise). You will find either of the last two are more effective, than using the front leg only.

In the case of serves that stress the shoulders and back, the front leg becomes the primary or sole initiator. It's hard to say since I don't know of any
force plate studies that isolated legs. however, may guess is if 80% of force is from the front leg, there is a high chance of improper mechanics. If 60/40% front/back, that may be typical good mechanics of foot-up. But initial forces are still from the back leg (backswing, loading phase) even if primary forces are front-leg (upwards swing). That is, early in the serve, back leg takes 80-100% of loading and then during mid-loading (both knees flex 60/40, etc.

Forces developed are subtle. We often don't see that. We do notice racquet head speed and physical flexion, extension, and other mechanical movements. But take the case of walking up and down stairs. Subtly we know that it takes more energy to walk upstairs but the forces involved are actually less. Going downstairs is easier (less work) but the forces involved are greater. Going upstairs requires 3.5x body weight forces whereas going downstairs exerts 5x body weight forces. We might see this second action as passive but it's still forces (eccentric muscular contractions).

The greatest forces in the serve? It is actually landing on the front leg. Which we often don't think about. Jump may result in forces up to 12x your body weight. In the case of the serve, the forces are somewhat less, perhaps 5-9x (maybe same as going downstairs and light jumps) body weight on the front foot. But keep in mind, it's one leg which is tremendous force.

In summary, forces developed going upwards are considered most effective being developed off the back leg. And again, this does not eliminate use of the front leg. If the front leg is used out of proportion, e.g, 90% of the force off the front, we often see stress developed in the back and shoulders.

Some insufficient use of the back leg can be seen with Melanie Oudin, back in :

http://www.youtube.com/watch?v=05bOIb57AIg

Compared to:

http://www.youtube.com/watch?v=hr5GHk0nTBs

In the latter video, she is actually closer to ideal. However, she tried the former at a later stage (perhaps not happy with results in the latter video).

Despite the leg drive, there is very little core rotation away (in the loading or early cocking phase). Unfortunately she corrected the serve by changing the stance rather than rotating her core/hips/shoulders. The former video serve at 0:07 shows use of back extension and flexion to provide force instead of from the ground. So technical, her serve may potentially lead to some injuries (core and shoulder).

[stotty]

This is a bummer for me because I have been for years teaching the platform wherever feasible and always gotten players to drive off the front leg...teaching the back leg is a post...a means of being able to transfer weight backwards then forwards to the drive off with the front leg.

When watching pro's, the back leg seems to get dragged up into the air so early in the process...the drive up seems like it must come off the front leg if the ball toss is in front of the body...the back leg looks like it's simply going "along for the ride".

When I try it, I cannot seem to be able to drive off the back leg or anything close. I am really struggling to understand the concept.

On another subject, has anyone got any thoughts about how much the arm should break at the elbow around the trophy position?

Ferrero has very little

http://www.tennisplayer.net/members/strokearchive/pro_men/jcferrero/jcferrero_serve/jcf_1st_serve/jcf_1st_serve.html?JCFerrero1stSDeuceCourtLevelSide1.mov

Lendl breaks a lot

http://www.tennisplayer.net/members/strokearchive/modern_legends/ivanlendl/lendl_serve/lendl_serve.html?LendlServeAdBodyRotationSide.mov

I see Murray is roughly equal to Ferrero but breaks much more as the racket starts to descend in to the racket drop, which would be better seen from an ariel view. But you can still see this quite clearly if you toggle through Murray's clip from the trophy position onwards. Toggle through Ferrero's clip through from the trophy to the racket drop and you will see the angle of his break doesn't change.

http://www.tennisplayer.net/members/strokearchive/pro_men/andy_murray/am_serve/am_arm_action/am_arm_action.html?AM1stSDeuceArmActionSide1.mov

Which leads to the question, is the angle of the break around the trophy position significant in terms of power and spin? Or are some players (Murray) compensating later in the process, by breaking more as they start to descend in to the racket drop?

[johnyandell]

Doug,

Interesting as usual but here is the big unanswered question. Players are usually intuitive in feeling what works. Yet virtually no top women use the platform.

Any thoughts about that? A few years ago at the request of the USTA I worked with a top female college player and changed her from an extreme foot wrap around to the right pinpoint to a moderate platform with less offset than Fed.

It looked great, worked great, she could kick the ball for the first time. USTA coaches were pleased...

Later that year I decided to go check out the fruits of this labor at one of her matches. You can probably guess what I saw. Right back to the old stance.

I asked her afterwards why she had changed back. It was almost as if she didn't realize it had happened but she also said that it simply felt natural the way she served...

Of course you could say it was just her, but she is in the overwhelming majority of elite women players.

[DougEng]

Doug,

Interesting as usual but here is the big unanswered question. Players are usually intuitive in feeling what works. Yet virtually no top women use the platform.

Any thoughts about that? A few years ago at the request of the USTA I worked with a top female college player and changed her from an extreme foot wrap around to the right pinpoint to a moderate platform with less offset than Fed.

It looked great, worked great, she could kick the ball for the first time. USTA coaches were pleased...

Later that year I decided to go check out the fruits of this labor at one of her matches. You can probably guess what I saw. Right back to the old stance.

I asked her afterwards why she had changed back. It was almost as if she didn't realize it had happened but she also said that it simply felt natural the way she served...

Of course you could say it was just her, but she is in the overwhelming majority of elite women players.

Great mystery, isn't it? I don't know exact numbers but it's worth looking into it. Ben Kibler has all the numbers for maybe 250 WTA and 150 ATP players. I think it maybe 80% of women are foot-up and 50-60% of men. But the question is improper foot-up or proper foot-up. So of that 80% women, 80+% may be improper. Of the men, maybe 50+%. So overall, something like 60% of WTA are deficient in use of the legs and overstressing back/shoulders. Whereas maybe 25% of men have those problems.

As you mentioned, there is also whether the foot-up is sideways or forward. The sideways can be done properly. The forward is often accompanied by stress on the back and shoulders. In addition, regardless of foot-up or foot-back, the shoulders sometimes get misaligned where players try to pull the elbow back hoping to coil or arch the back. But this is done improperly and hence, fair risk of shoulder injury.

I can find out the numbers since Sport Science Committee meets in 2 weeks but I can't be there. I'm sure Ben can send me his powerpoint notes.

Personally, I think it is related to jumping power. Many women can swing very hard, almost as much as men. But serving (and overheads) presents a different problem due to height and jumping disadvantages. The women's game tends to be flatter. If a WTA player can produce 85% of the power of a ATP player, she'll want to proportionally use it more for pace rather than spin. Therefore, rather than hitting spin serves 90 mph and spinny groundies at 70 mph, she prefers to hit 100 mph serves flatter and groundies flatter at 85 mph. Given the height disadvantage, this seems almost an oxymoron.

Take the case of junior players. Girls will almost always hit a little mini-tennis and then move back quickly and hit hard. Boys will tend to stay longer at the net and play around with silly shots and heavy spin (under/top). The same for college players. Girls have a harder time adjusting to slower pace mini-tennis. Women too...men seem to like playing around more and work on feel/spin.

Translated to serving, this means guys may go for more variety on serves.
In addition, heavy spin on the groundstrokes requires more arial footwork. We see more spin moves from the ATP players but more on-ground pivots from the women who hit flatter.

Track and field world records run parallel. Sprint records show women are at 90% of the men. But jumping records are 85% of the men. Given perhaps the 5% may be the height difference. But compare NBA and WNBA players at 6'1" - 6'4". All the men can dunk but rarely can the woman dunk. Women have more jumping issues, with 6-8 times more frequent ACL injuries. Therefore, women have more problems with vertical displacement than men.

I also used to coach squash and this is quite widespread in a different manner. Many women have difficult getting down low to the ball whereas men, who are taller, have little problem with the low balls. One could argue it is core, knee and glute strength. But I am not so sure. Women tend to be more monotonous with stroke variations. They tend to play more similarly, less volleys, etc. It is quite similar to tennis. This may actually be a reflection of how a woman thinks in sports...perhaps related to an ability to focus differently. Maybe also why women are better students. I do find women tend to stick at one theme better than men. She may also transfer this ability to sports. I am a bit guessing here since there is nothing in research that I have seen. Rather some indicate women are better multi-taskers...which I'm not sure. I do find them more focused and often better in attention to details. From an attention focus, therefore women may have better narrow focus. Men may be more broad in focus.

This could be reflected in ADHD. 13% of boys have ADHD and 5% of girls. Girls tend to be more cooperative and subdued. Boys tend to be hyperactive. This actually may be more a reflection of attention focus whether ability to be narrow or distracted. Hence mini-tennis with lots of variety, trash-talking and wavering attention is the norm for most junior boy or college male players hitting. Girls may focus more on one type of hitting...and if it doesn't work, she takes her narrow external focus and turns it inwards (hence, an emotional reaction that she is letting down teammates, etc). We've all seen the girls who cry when they can't play well. Boys do it too, but rarer...and tend to blame externally instead (e.g, John McEnroe).

Getting fairly deep here...but it may be an important difference, maybe biological rather than cultural (as many believe).

Best,
Doug

[johnyandell]

Interesting. Very Interesting. Especially about the spin and speed trade offs. And the use of the arm speed verus use of legs. And I happen to agree.

So the next question would be to what extent can women be trained to use the platform--or at least a less extreme pinpoint. And how much of that training would be not technical but strength related??

[DougEng]

Interesting. Very Interesting. Especially about the spin and speed trade offs. And the use of the arm speed verus use of legs. And I happen to agree.

So the next question would be to what extent can women be trained to use the platform--or at least a less extreme pinpoint. And how much of that training would be not technical but strength related??

Definitely! Trainers/PT work with female athletes in jumping to reduce valgus knee stress. Usually they do basketball, volleyball, soccer players. But why not tennis? Most trainers are not involved in tennis and are not aware of technical differences/problems. Some coaches are aware but are not sure how to tackle issue. Ben Kibler's study (supported by WTA/ATP) is expected to be disseminated...but I expect a physical training protocol to follow maybe in 2 years...I hope. Mark Kovacs (and Todd Ellenbecker) already has some training routines for the serve. But it's not platform specific. However, it works on eccentric strengthening, back leg loading, etc. Some of it was posted in this thread I think.

But it would be a great talk. And article
But if I were to create such a program, I'd probably want medical community backing...but I can speak to some there...

At least my juniors girls I coach learn to use pinpoint properly or platform! In fact, sometimes I find the narrow platform to be useful. I think Justine Henin was using that at some point late in her career.

[johnyandell]

Doug,

If we can work with those guys to develop and make that type of insight and training visible and accessible and give it a platform, that would be a GREAT contribution. Looking forward to doing the articles with Ben. If you are amenable I would love you to interface about the training aspect and see what is desired/possible.

John

[stroke]

Here is a link to a old tennis video that may be of interest, and possibly tie in to the discussion here regarding ground force on the serve. It features Roscoe Tanner, who Doug Eng referenced earlier in a post in this discussion.

http://www.youtube.com/watch?v=42STJgl2K4E&sns=em

[jasonfrausto]

Interesting info Doug, which ties heavily into what many believe and have seen with their own students. Almost all of my female students serve platform, but they are the exception compared to many of their peers. Madison Keys seems to be hitting bombs on her serve from a platform stance, but she is clearly the exception at this point rather than the rule.

This difference biologically is also part of my thought process as to the effectiveness of the SSC (stretch shorten cycle) on the forehand for women. As Rick states in his video, the stroke starts from the ground up. When I see women getting the same ball speed/spin rates as men I'll be a firm believer that the ATP technique is the best way for the women to hit their forehands. Or until the WTA top 10 is filled with ATP type forehands I'm a firm believer that there is room for both techniques and that the classic WTA style forehand isn't going away anytime soon.

I've read through all of your posts here Doug and really enjoy all the technical/data posts. Very helpful.

[DougEng]

Here is a link to a old tennis video that may be of interest, and possibly tie in to the discussion here regarding ground force on the serve. It features Roscoe Tanner, who Doug Eng referenced earlier in a post in this discussion.

http://www.youtube.com/watch?v=42STJgl2K4E&sns=em

Very cool. Everyone knows Vic but Gideon Ariel was a ledge, too!