Another pronation question

#1
I've spent some time looking at various slice serve vids and it seems clear that many either don't pronate or do so after the ball has left strings. The no pronation group talks about the "dirty diaper" serve and in this video she clearly doesn't pronate and finishes with racket face pointing up. My question is do you pronate on slice and if so when?
 
#3
I've spent some time looking at various slice serve vids and it seems clear that many either don't pronate or do so after the ball has left strings. The no pronation group talks about the "dirty diaper" serve and in this video she clearly doesn't pronate and finishes with racket face pointing up. My question is do you pronate on slice and if so when?
Only internal shoulder rotation and pronation until impact matter for the ball.

Advance the video until the frame where the ball has been hit and motion blur to the left is shown in the frame. Use the "." and "," keys to move one frame on Youtube. Use the "," to move back from where the ball first shows for sure that impact has occurred. Joint motions involve bone movements. The hand and racket are probably the best indication of the bones in this video. The racket is held in the palm of the hand. Try it with a racket, the racket shaft moves with the palm. Watch the shaft of the racket as it moves back from the frame of impact. We can see this rotation of the knuckles and racket shaft. We can't see how much of this motion is internal shoulder rotation or pronation. But the hand and shaft of the racket are rotating as they should for ISR and pronation. It does not look like much ISR and pronation.

It's hard to get a rough measurement of how many degrees of ISR + pronation preceded impact from videos. However, it could be done if the server cooperates after the shot and the rotation is videoed with the same camera position, shoulder and arm positions and lighting. The hand and racket could be videoed near an angle scale. ISR is shown by the arm bone between the elbow and shoulder joint. Pronation is show by the amount of rotation between the elbow and wrist. I find it very difficult to observe pronation leading to impact. An early measurement by Elliott said that 40% of racket head speed at the instant of impact was ISR and 5% was from pronation.

In degrees, how much internal shoulder rotation occurred before impact? Hard to tell but in your video it does not look like much ISR plus pronation from the hand & racket. Some.

You want to study representative serves. If one serve looks as if there was not much ISR + Pronation and the pace is low, maybe that serve was just not good. What is the pace for Serena's typical serve, fastest serves and that serve? That's a lot of work..........

Kick serves sometime may appear to have little ISR. And I think that they actually have less ISR because the racket impacts the ball before the racket reaches its peak height. I just looked at the "second" Rafter serve (FYB) and his elbow is straightening quite a bit, late I guess, while the ISR is occurring. ?
 
Last edited:
#4
Slice serve.
For stop action single frame on Vimeo, click Vimeo, full screen, hold down the SHIFT KEY and use the ARROW KEYS.

Look at the elbow and its shadows. The ISR lasts only about 1/4 second as this is played back (240 fps recorded, 30 fps played back). The ball curves to the left and goes wide. The spin can be seen by the ball print. The racket impacts the ball near the racket's highest position reached. I often can't tell the difference between a slice and flat serve because the highest racket height is similar. But the distinct kick serve will always show the racket go higher in the frame after impact (at 240 fps) (but cameras looking up at impact may not show this).
 
#5
I've spent some time looking at various slice serve vids and it seems clear that many either don't pronate or do so after the ball has left strings. The no pronation group talks about the "dirty diaper" serve and in this video she clearly doesn't pronate and finishes with racket face pointing up. My question is do you pronate on slice and if so when?
Sorry but definitely pronating. How do you think a racket moving on edge will hit the ball if it doesn't open at some stage and what opens it except pronation? Slow it down even further by playing at 0.25 speed when the racket starts going up towards the ball and go frame by frame by using the arrow keys. You will see it.
 
Last edited:
#6
Well let me say I feel it is pronation up to contact but that is where she seems to stop. The racket never continues to have strings face right. I feel i'm getting a better understanding that even if they finish pronating it is well after ball has left strings
 
#7
Sorry but definitely pronating. How do you think a racket moving on edge will hit the ball if it doesn't open at some stage and what opens it except pronation? Slow it down even further by playing at 0.25 speed when the racket starts going up towards the ball and go frame by frame by using the arrow keys. You will see it.
Matter of direction and ball position at impact. Ie. Where you toss and where do you hit it from. If you look at where the racket head is moving at impact and where the ball starts. There’s the answer.

You can cut thru the ball with constant angle of the face. But you don’t hit with the edge, but cosine of the string bed.


——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
 
#8
Well let me say I feel it is pronation up to contact but that is where she seems to stop. The racket never continues to have strings face right. I feel i'm getting a better understanding that even if they finish pronating it is well after ball has left strings
The racket seems to face right at 20 seconds.

What happens leading to impact has to happen for a high level serve. I believe that what happens after impact depends on ball location on the racket at impact, how servers choose to stop their high speed arm and racket - their muscle use and various angles, for example, the forearm to racket shaft at impact.

There is a frequent position of the racket often called 'fully pronated'. I believe that if you look for that it will not be on all high level serves but is is on a lot of high level serves, a good sign. I have not made a study of the statistics.

I have seen variations well before impact and well after impact, but much fewer variations the last 30 milliseconds before impact. If you want to understand this issue look at several serves of one type from different servers, randomly selected, and see how many reach the 'fully pronated' position with racket face facing the side. That could settle the issue. I believe 'fully pronated' is a positive sign but it is not a necessary or sufficient condition for calling a serve a high level serve.

Far more interesting and important are the details in the last 30 ms before impact. For example the timing of the arm becoming near straight relative to ISR and the amount of ISR in degrees to impact.
 
#10
Well let me say I feel it is pronation up to contact but that is where she seems to stop. The racket never continues to have strings face right. I feel i'm getting a better understanding that even if they finish pronating it is well after ball has left strings
From racquet moving edge on to contact is pronation the rest is follow thru. Some players end up with racquet head facing right some don’t but that doesn’t mean they didn’t pronate. Going off track a little bit. I struggled with the edge on and contact for a long time. I read in a book that you delay the from edge on to contact, until the very last second. I found that very hard to do so I just make contact without thinking about it. It was bad advice. It doesn’t matter as long as you come in with racquet edge on.
 
Last edited:
#11
Maybe i'm explaining myself wrong but I guess i'm trying to talk myself out of what worked yesterday on the court. Yes I pronated to contact but finished similar to what Jeff Salzenstein shows on his kick dirty diaper serve. Both times I got extreme slice and finished point on volley. One of the vids I watched indicated this can work at rec level but inhibits progress to upper levels. I'm not going to be a pro and so are most on this forum so maybe try it.
 
#12
To my understanding the chimera of not pronating is related to the terminology; pronation is used in tennis different from physiology

The move Ian shows by his laptop is a combined move, where both ISR and pronation happens simultaniously, and looks to be more of internal shoulder rotation than pronation. Were it only pronation, his upper arm would not twist along the move.

Pronation in fact is only the forearm move, that twist the palm inwards and should be observed by the elbow orientation in relation to his elbow, not the chest.

If you look carefully Serena Williams’ elbow is not towards the net/target she is serving, but the side post or even slightly more towards the side fence just before impact. And palm is pointing very close to the same direction in relation to her elbow at impact as it was right before the hit being pretty neutral.

However, internal shoulder rotation has opened the hand and racket face to ”pronated position” and the racket releases right and down around over her wrist, which moves into ulnar deviation as the racket head drops.

If you reach the big-L position before the racket stretches up above the hand on the edge a slice is possible to hit without pronating at all (forearm move), but by internal shoulder rotation, which seems to be mostly the culprit opening the face in Ms Williams’ slice.

The tell-tail would be the wrist hinging towards the pinky side past impact (ulnar deviation). Had she pronated the forearm, the racket would be facing down and wrist would flex, instead of releasing on the edge to ulnar deviation.


——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
 
Last edited:
#14
This pronation still is probably the most confusing and bipolar topic in tennis.

How much pronation is enough to get max out of your serve I wonder.

There are a ton of high level players who pronate till contact and even slightly after contact, but they do not continue to pronate till the absolute end so that their strings face the right side or even upwards in some cases.

Then there are high level players who pronate till contact and after contact and even after that till the racquet is pointed completely right or upwards.

The question is how much if any do these effects affect the serve.

Both pronate till contact and after contact, but some stop the internal rotation and pronation earlier and some let it stop when it reaches the end of the joint motion.

Maybe could be related to the toss and swingpath and everything.

But certainly a vast majority of WTA players, some ATP players and a vast majority of D1 college players pronate till slightly after the ball leaves the racquet and then pull the racquet down, instead of leting it pronate so the racquet faces the right side.


If you look in slow motion a few serves from start from both guys you can see most of their serves have these qualities, here and there a serve might have that full motion pronation.


Thiem, sometimes have that full motion pronation and sometimes just slightly after contact


Djokovic here no full pronation but sometimes does fully pronate



I think this topic is quite complex and interesting and very bipolar

But from video evidence its clear we have high level players at D1 college levels, Futures, WTA and ATP who either:

1.Pronate up till contact and then let the wrist snap forward instead of continuing to pronate (The racquet face rotates till contact and then stops rotating even slightly before and instead starts snaping down via wrist)
2.Pronate up till contact and slightly after contact but then stop pronating as they pull the arm down earlier (The racquet face rotates till contact and after contact continues to rotate but then stops at some point, sooner or later and faces slightly sideways)
3.Pronate up till contact and let the racquet pronate till the end of the joint motion (The racquet face rotates till contact and after contact continues to rotate and continues so till the end of the joint natural motion and faces very sideways or even upwards)
4.Depending on the serve do variations of 2. and 3. or sometimes even 1.
 
#15
For visual:





1.Pronate till contact and then wrist starts to bend forward
2.Pronate till contact and after contact but stop a bit after (this can vary alot sometimes more sometimes less)
3.Pronate till contact and after contact till the end of joint motion completely
 
#16
@FiReFTW, I think they do not pull the racket down. The kinetic energy is directed by the pivot point at the shoulder and is enhanced by the gravity.

The speed bringing the racket down is more or less just a result of the effort put in throwing the racket up. The arm long axis acceleration thru the shot, will determine the amount of isr in the end and weather the face is pointing down or on the outside. Ofcourse the range of motion in the shoulder is restricted by the players moveability. Same effort will therefore give different results from player to another.


——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
 
#17
From racquet moving edge on to contact is pronation the rest is follow thru. Some players end up with racquet head facing right some don’t but that doesn’t mean they didn’t pronate.
Exactly, you got it !

Pronating is a very simple and natural movement, nothing forced. People seems to make pronation complicated but it us just a part of a natural throwing movement.

If You dont belive me, then just do a little experiment, film (slow motion) your self throwing a tennis ball, throw natural and loose and I will guarante that you will see that you pronate, it is a natural movement, not complicated at all.

Cheers, Toby
 
#18
@FiReFTW, I think they do not pull the racket down. The kinetic energy is directed by the pivot point at the shoulder and is enhanced by the gravity.

The speed bringing the racket down is more or less just a result of the effort put in throwing the racket up. The arm long axis acceleration thru the shot, will determine the amount of isr in the end and weather the face is pointing down or on the outside. Ofcourse the range of motion in the shoulder is restricted by the players moveability. Same effort will therefore give different results from player to another.


——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
@FiReFTW, I think they do not pull the racket down. The kinetic energy is directed by the pivot point at the shoulder and is enhanced by the gravity.

The speed bringing the racket down is more or less just a result of the effort put in throwing the racket up. The arm long axis acceleration thru the shot, will determine the amount of isr in the end and weather the face is pointing down or on the outside. Ofcourse the range of motion in the shoulder is restricted by the players moveability. Same effort will therefore give different results from player to another.
Yeah but if you watch 1 player they might have very different amount of pronations from serve to serve, but like you said, alot of things are the result of that and can affect it, effort, swingpath, ball toss.. serve type
 
#19
Now that I think of it, it is the racket drop supination (forearm move) at racket drop, which makes the biggest difference.

If there is no supination at the rh lowest point, there is not much range to be accelerating the racket in the upward motion and the racket will be open early.

The hardest servers have their forearm really close to neutral on flat serves, which brings us to the significance of the combination of ISR and pronation and timing them properly relative to one another.

If you have strong ISR prior to impact, you are not going to pronate much, because that would turn the racket face towards the side fence prior to impact.

If you start pronating (forearm) early, or have no supination at the racket drop, there is no room for ISR either, so, you end up hitting waiters tray by only extending the elbow and throwing the arm forward.




——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
 
Last edited:

jga111

Hall of Fame
#20
I've been making a concerted effort recently to pronate AFTER contact. I was never doing that before and always stopping at contact. It does make a difference in spin and sometimes power - I hit the back fence more often put it that way. (All dependent on my timing - my serve is still a work in progress).

My point is, I think players DO need to do more when it comes to pronating after contact but because it is becomes part of their muscle memory they don't even think about. Sometimes the amount of pronation will vary but I think this is because the player is not thinking about pronation per se, but the general trajectory and spin on the serve that the player wants to achieve. The pronation part after contact does need explicit attention..in the beginning, but obviously not when part of the muscle memory.
 
#21
I've been making a concerted effort recently to pronate AFTER contact. I was never doing that before and always stopping at contact. It does make a difference in spin and sometimes power - I hit the back fence more often put it that way. (All dependent on my timing - my serve is still a work in progress).

My point is, I think players DO need to do more when it comes to pronating after contact but because it is becomes part of their muscle memory they don't even think about. Sometimes the amount of pronation will vary but I think this is because the player is not thinking about pronation per se, but the general trajectory and spin on the serve that the player wants to achieve. The pronation part after contact does need explicit attention..in the beginning, but obviously not when part of the muscle memory.
People are complicating and overthinking pronation. Pronation comes natural in a throwing motion, and after contact it is simply follow thru. Be loose, dont force it, and it will happen, magic :)
 

jga111

Hall of Fame
#22
People are complicating and overthinking pronation. Pronation comes natural in a throwing motion, and after contact it is simply follow thru. Be loose, dont force it, and it will happen, magic :)
I think you're right. But I think I'm right too, in that for some players, like me, they have tightness in certain muscles which means unless they do the relevant conditioning exercises (I don't but should do), then they'll only ever be able to do so much.

For example, if you have tight shoulders, you'll need to hit a whole swathe of serves before you connect loosely. In the same way, if you have tight arm muscles, there is only so much you'll be able to pronate...

What do you think?
 
#23
I think you're right. But I think I'm right too, in that for some players, like me, they have tightness in certain muscles which means unless they do the relevant conditioning exercises (I don't but should do), then they'll only ever be able to do so much.

For example, if you have tight shoulders, you'll need to hit a whole swathe of serves before you connect loosely. In the same way, if you have tight arm muscles, there is only so much you'll be able to pronate...

What do you think?
Yes I do agree. For serve, being flexible is more important than being strong IMO. Being loose (think of your arm as a whip) is very important, you cant serve well if you are tight.

People focus too much and spend too much time thinking about complicated stuff like ISR, supination, pronotion etc. Internet is flooded with videos, but there are much more important issues with the serve.

Try like I posted in #17 to film youself throwing a tennis ball, you will be surpriced to see that you are doing pronation correct without even thinking about it.

Cheers, Toby
 
Last edited:
#25
We could also discuss the importance of the left arm (tossing arm), does it just fall down passive, or do players actively drive and pull it down to create more speed and power, just like with the forehand the left arm can be used to create rotation and is very important to the serve.

I am working with my coach to actively pull my left arm down to my stomach, to create momentum and more RHS, in his opinion this action gives more power to the serve than pronation :) but I hardly see this discuss here. People are too focused on the hitting arm. In a throwing motion the left arm is very important to create speed and rotation. In a serve all parts should be working together.

Cheers, Toby
 
#26
We could also discuss the importance of the left arm (throwing arm), does it just fall down passive, or does players actively drive og pull it down to create more speed and power, just like with the forehand the left arm can be used to create rotation and is very important to the serve.

I am working with my coach to actively pull my left arm down to my stomach, to create momentum and more RHS, in his opinion this action gives more power to the serve than pronation :) but I hardly see this discuss here. People are too focused on the hitting arm. In a throwing motion the left arm is very important to create speed and rotation. In a serve all parts should be working together.

Cheers, Toby
If you think of a karateka, what is he doing, when punching. It is the same human body executing different sports, so...


——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
 
#28
We could also discuss the importance of the left arm (tossing arm), does it just fall down passive, or do players actively drive and pull it down to create more speed and power, just like with the forehand the left arm can be used to create rotation and is very important to the serve.

I am working with my coach to actively pull my left arm down to my stomach, to create momentum and more RHS, in his opinion this action gives more power to the serve than pronation :) but I hardly see this discuss here. People are too focused on the hitting arm. In a throwing motion the left arm is very important to create speed and rotation. In a serve all parts should be working together.

Cheers, Toby
"do players actively drive and pull it down to create more speed" yes, ........

The function of the off arm on the serve has been discussed here. Search: off arm pull in serve Chas and similar terms.

"this action gives more power to the serve than pronation" no, but nobody knows how to measure 'power' in tennis usage. What units are used to measure tennis 'power'? Only Bahamonde around 2000 measured details of power that I know of. Kibler did some power also. Anybody have a single measurement? In tennis usage power is another undefined term. Of course, if your coach actually meant real pronation instead ot tennis usage 'pronation' (ISR) he could be right because 5% seems about right for each. Power is one of those safe words to use since nobody knows how much power is in any tennis motion?

Search -bahamonde tennis researchgate power

Joint Power Production During the Flat and Slice Tennis Serves
Conference Paper (PDF Available) · January 1997 with 157 Reads
Conference: Proceedings of the XIII International Symposium on Biomechanics in Sports

Ralph Bahamonde
Indiana State University
 
Last edited:
#30
People are complicating and overthinking pronation. Pronation comes natural in a throwing motion, and after contact it is simply follow thru. Be loose, dont force it, and it will happen, magic :)
Lot of people can, but allmost as many cannot throw properly. For them the natural would be somewhere between a proper and restricted throwing motion.

Given that both, my cousin and one fella here by his video footage, can throw. Their trophy position being too wide, neither of them cannot and will not let the racket loop down enough and on the play hand side of their body. Because of that all the racket loop stays above their shoulder line, which really restrickts proper on the edge upward motion of the racket and result more of a waiters tray -type of serve with quite slow acceleration and low ball speed in their serves.

One other thing, that restricts proper throwing motion is the early uncoiling of the shoulders. All that put together result a bent arm hit with racket head opened or perpendicular to the target really early in the serve.


——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
 
#31
People are complicating and overthinking pronation. Pronation comes natural in a throwing motion, and after contact it is simply follow thru. Be loose, dont force it, and it will happen, magic :)
People say this a lot, and it's definitely true for some people. However, for a lot of people it's not true. Some people can throw reasonably well, but when they try to serve overhead it completely falls apart. I think if you learned to throw as a kid then it's probably a lot more natural feeling. Kids experiment a lot and many can learn a lot of things through experimentation and repetition without any coaching or teaching.

Even then, there are still a lot of kids that will only progress so far. When I was in little league in grade school, maybe 4th or 5th grade there was only 2 kids on the team that would play catch with me. The other kids complained that I threw the ball too hard. I just kept trying to tell them to catch the ball in the pocket and it wouldn't matter, but they didn't like my solution. So I ended up playing catch and warming up for pitching with the same two kids all year.

I think people obsess over serve mechanics because the serve is so important, and the technique is completely non-obvious. I had no clue about the racquet turning into the ball when I first started learning to serve. It's not something you really see when you watch a high level server as it happens so fast and you don't really know what to look for when you are first learning. So then when you actually do know what's happening it's quite a challenge to make that work in your own motion which is almost certainly already trained incorrectly. That makes it a struggle.

Anyway, it's worth spending some time on to learn it because when you do it opens up a whole new realm of possibilities for your tennis game.
 
#32
People say this a lot, and it's definitely true for some people. However, for a lot of people it's not true. Some people can throw reasonably well, but when they try to serve overhead it completely falls apart. I think if you learned to throw as a kid then it's probably a lot more natural feeling. Kids experiment a lot and many can learn a lot of things through experimentation and repetition without any coaching or teaching.

Even then, there are still a lot of kids that will only progress so far. When I was in little league in grade school, maybe 4th or 5th grade there was only 2 kids on the team that would play catch with me. The other kids complained that I threw the ball too hard. I just kept trying to tell them to catch the ball in the pocket and it wouldn't matter, but they didn't like my solution. So I ended up playing catch and warming up for pitching with the same two kids all year.

I think people obsess over serve mechanics because the serve is so important, and the technique is completely non-obvious. I had no clue about the racquet turning into the ball when I first started learning to serve. It's not something you really see when you watch a high level server as it happens so fast and you don't really know what to look for when you are first learning. So then when you actually do know what's happening it's quite a challenge to make that work in your own motion which is almost certainly already trained incorrectly. That makes it a struggle.

Anyway, it's worth spending some time on to learn it because when you do it opens up a whole new realm of possibilities for your tennis game.
I played handball (very big sport in many countries in Europe) as a kid, and there you learn to have all kind of shots (different throwing motions), so I guess I am a bit bias toward throwing motions, and perhaps thinking everyone can throw a natural ball.

Later I became a pro athlete in volleyball, and there spiking and serving are kind of like a tennis pancake serve.

I had a hard time, and sometimes still have (muscle memories) with overhead and serve, here I tend to face the net too much and also sometines (unconsciously) change serve grip (continental to eastern forehand) in the middle of my motion (my coach made me aware of that), so my challenges could be very different from other players. I now tend to hold a strong continental grip (more towards the eastern backhand grip), so I guess my pronation also comes more natural.

Great input that made me think that perhaps not all players have a natural throwing motion.

Cheers, Toby
 
#33
People say this a lot, and it's definitely true for some people. However, for a lot of people it's not true. Some people can throw reasonably well, but when they try to serve overhead it completely falls apart. I think if you learned to throw as a kid then it's probably a lot more natural feeling. Kids experiment a lot and many can learn a lot of things through experimentation and repetition without any coaching or teaching.

Even then, there are still a lot of kids that will only progress so far. When I was in little league in grade school, maybe 4th or 5th grade there was only 2 kids on the team that would play catch with me. The other kids complained that I threw the ball too hard. I just kept trying to tell them to catch the ball in the pocket and it wouldn't matter, but they didn't like my solution. So I ended up playing catch and warming up for pitching with the same two kids all year.

I think people obsess over serve mechanics because the serve is so important, and the technique is completely non-obvious. I had no clue about the racquet turning into the ball when I first started learning to serve. It's not something you really see when you watch a high level server as it happens so fast and you don't really know what to look for when you are first learning. So then when you actually do know what's happening it's quite a challenge to make that work in your own motion which is almost certainly already trained incorrectly. That makes it a struggle.

Anyway, it's worth spending some time on to learn it because when you do it opens up a whole new realm of possibilities for your tennis game.
I had a tennis course as a 7- or 6-yo. The guy teaching us was maybe a 5.0 or 5.5 player at the time.

He showd us the positions to reach and the full motion. After the course, I practiced for 6 to 8 hrs a day two summer holidays from school and mastered the motion.

I have said this before, but I will repeat it time and time again.

The problem with tennis instruction and other sports too is, that they have sports spesific translations for common or physiological terms describing single joint moves and speak different language from what people know.

Any sport is doable, but the sport coaches have their own vocabulary and explanations for common terms, like pronation, which in the upper limb movements would only translate to forearm movement, not the ”tennis pronation”, which include the internal shoulder rotation to go with.

Trouble is, that if you only pronate (twist your palm inwards by forearm only), the serve is crap.


——————————
No more on pain meds - all contributed matter and anti-matter are still subject to disclaimer
 
#34
The problem with tennis instruction and other sports too is, that they have sports spesific translations for common or physiological terms describing single joint moves and speak different language from what people know.

Any sport is doable, but the sport coaches have their own vocabulary and explanations for common terms, like pronation, which in the upper limb movements would only translate to forearm movement, not the ”tennis pronation”, which include the internal shoulder rotation to go with.
This is quite true, and not just of sport. It's true in any area of specialized knowledge. In fact it's so true in some areas that apparently even "experts" in the field can't pick out truth from fiction. https://www.chronicle.com/article/What-the-Grievance/244753

In any event, when it comes to learning from paid instruction, if your coach/instructor can't demonstrate techniques and can only rely on descriptive language, you should probably find a different instructor.
 
Top