matterer

Rookie
I finally figured out how to do internal shoulder rotation now I just need to know to do knee adduction and internal hip rotation in order to jump. Am I supposed to suppinate my ankle or do I pronate? Please help I am stuck on the ground.
 

Digital Atheist

Hall of Fame
I finally figured out how to do internal shoulder rotation now I just need to know to do knee adduction and internal hip rotation in order to jump. Am I supposed to suppinate my ankle or do I pronate? Please help I am stuck on the ground.
Some might say one troll post deserves another :p
Show some video of this serve and we can help you "take off"! And with the state of smartphones these days, there is really no excuse (who needs 240fps!). I am skeptical.
 

Chas Tennis

G.O.A.T.
Here's a Toly serve video with a Toly composite picture at 1:05 and a research publication. The ball trajectory, hand path and racket path are shown. Click to expand.

Clearly video evidence shows that things are more complicated than 'on edge' can describe because you are not considering video evidence.

Here is a Toly composite video. Be sure to see Toly's composite frame at the end around 1:05.
To view single frame on Youtube, stop video and use the period & comma keys.

This video agrees with the serve biomechanics that was confirmed by research in a 1995 publication by Bruce Elliott, Robert Marshall and Guillermo Noffal
 
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Chas Tennis

G.O.A.T.
What do we know is true about the earliest confirmed use of internal shoulder rotation, ISR.

Meet Gerald Paterson in 1919.
Meet Gerald Paterson

The first server is Gerald Paterson, quality slow motion included.

This is one of the clearest dislplays of internal shoulder rotation, and from 1919!. The toss does not look very high. ?

Gerald, an Aussie, was known as the "Human Catapult" because of his serve. He overcame a backhand weakness to win Wimbledon singles and doubles titles.

I am searching for Rosco Tanner in slow motion who has one of the lowest tosses. The unusual low toss is about the only technical thing he mentions in his autobiography, Double Fault.

I don't know if this is the earliest proof of the serving technique based on ISR. But until other information comes to light, this shows ISR by the shadows at Gerald's elbow in 1919. Gerald has the record in my book.

The high speed film camera has a very fast shutter speed, resulting in small motion blur. I don't know when high speed film camera technology reached this quality. ?

In 1919, I believe the tennis rules required that one foot remain on the ground. That rule was changed in about 1963, after which players could jump off the ground.

Another Gerald Paterson video. Gerald was not looking at impact in this video. Type serve, unknown.
To single frame on Youtube, stop video, go full screen and press the period & comma keys.

In the 1970's, over 50 years after Gerald Paterson serve videos like these, I was studying tennis books and Tennis for the Future by Vic Braden..... I missed ISR entirely due to ignorance. It would take me another 41 years to learn about Internal Shoulder Rotation and the tennis serve on this forum (2011).

Internal Shoulder Rotation for the tennis serve was known to badminton researchers by at least 1985. ISR was confirmed in tennis finally and published by Elliott, Marshall and Noefell(?) in 1995. ISR was used by many pro tennis players and who knows who else. Too bad that some one person who lived through this can't tell the story. It would be interesting and especially good regarding True & False.

Where are we now?
 
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Valle2020

New User
I'm genuinely interested in feedback on my serve. During practice the other day, I threw away a few flat first serves, Tried to alternate wide/t placement but didn't end up perfect with placement. I started playing 4-5 years ago but has been since put in quite an effort to develop and therefore, obviously a lot more hours compared to the average rec. player. I consider myself somewhere around 4.5. During matchplay, max speed on first serves is around 100 mph and average usually around 82-83mph. To much flat serving kind of kills my arm so more often then not I play spin serves rather then bombs. Avg on second usually around 80-81 so not much of a difference.

All speeds measured in kmh and converted to mph with playsight, see example from yesterday below

What i'm looking for is "easy" tips on technique that actually can be adapted at a rec level to further improve.

Video

Stats
 

Digital Atheist

Hall of Fame
As per the discussion in @Curious's Obsession thread, I went and videoed a couple of different angles to see if some were better than others for viewing ISR. Here are four serves from different perspectives (one is from some of the stills above) and the first one was hit today.


Here are the relevant frames from what I consider to be the best angle. The serve below is not full-bore, and it seems like I get slightly less turning out of the racquet strings compared to when I try and blast, but I think the shoulder rotation is still easily discernable (to some degree anyway). I'll let @Chas Tennis offer his opinion on that, since it's not something I'm that familiar with.
AL9nZEX9mQw3qnhfEdrNlSbcxMI6eehtnJS429ajqRrt1ojMY1P_nAiPVPFMiLNHXyLVJcLdo8mknB4aG0QDRn5OueGvFQ_UKS2W0AtzR1zQ01fs3L2HzekKlYwwiotAaV7MHnZnHz89DhW0jSlK8WOyp7gE=w1300-h524-no


Feel free to comment on anything except my left hand (which looks like it's oddly deformed).
 
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Digital Atheist

Hall of Fame
I'm genuinely interested in feedback on my serve. During practice the other day, I threw away a few flat first serves, Tried to alternate wide/t placement but didn't end up perfect with placement. I started playing 4-5 years ago but has been since put in quite an effort to develop and therefore, obviously a lot more hours compared to the average rec. player. I consider myself somewhere around 4.5. During matchplay, max speed on first serves is around 100 mph and average usually around 82-83mph. To much flat serving kind of kills my arm so more often then not I play spin serves rather then bombs. Avg on second usually around 80-81 so not much of a difference.

All speeds measured in kmh and converted to mph with playsight, see example from yesterday below

What i'm looking for is "easy" tips on technique that actually can be adapted at a rec level to further improve.

Video

Stats
Nice serve but you should definitely start a new thread and re-post that video, since not everyone that offers advice is following this thread and your serve deserves it! I guarantee you will get some good feedback.

It looks like you did your best to get the entire serve into frame so well done on that, but it is much better to video in landscape with the phone anywhere from 4 to 7 feet off the ground. I understand that might be tricky if you don't have an attachment, but maybe you can get someone to hold the camera from behind while you hit a few? Just a suggestion since the quality will be vastly improved (and please don't link YT Shorts for analysis since they can't be frame advanced, and not everyone knows how to find the full version from the Shorts URL).

From what I saw it looks excellent but I will give the rest of my opinion once you start your own thread.
 
The serve is more like a shot put than a throwing motion - Meike Babel is on board with that analogy and she could play a bit. But is it true? Dr. Mark Kovacs - a well renowned sports scientist and excellent tennis player - is one of the pioneers of this concept if I'm not mistaken, so I guess there is some basis.

I just don't see it or feel it when I'm serving, and don't know how it could even be useful. That's just me, and I might be in the minority.

Imo this is the action you want, demonstrated by Patrick M where at 16 seconds and he says "the elbow comes in front as the hand goes down".

I feel like the shot put cue for a lot of rec players could result in going straight up from the trophy position (as Meike demonstrates) skipping that vital component, and they will have NO ESR and a terrible racquet drop, among other things. What is so wrong with learning to throw UP, for height and not distance?


The term Dr Kovacs uses is long axis rotation, where it all happens as part of one larger movement (including the shoulder). Now that I can understand.
I rag on Patty M constantly but actually that elbow tip was quite helpful.
 

Chas Tennis

G.O.A.T.
Whoops!

I have to revise my views on the term 'wrist snap' during the tennis serve. Click expand to see correction.

You are lucky if you are interested in the wrist joint. Check it out, it's mostly bone, it's about twice as wide as it is thick. An object like that cannot hide what it is doing from a video camera.

To see what the wrist is doing, watch a high speed video.

Avoid using easy to remember undefined tennis terms to characterize tennis strokes unless you see the strokes for yourself. Search for 'wrist snap' in videos and post it if you ever find 'wrist snap'. (Define 'wrist snap' first.)

CORRECTION- The wrist joint goes from very extended to less extended at impact, that is flexion. It is fast flexion, reasonable to call it wrist snap. Always look at videos for what is true. Define 'wrist snap' first. The time corresponds to the time of ISR start to impact, is roughly 25 milliseconds. The upper arm rotates roughly 90 degrees from ISR start to impact for this serve.

Click "V" & go full screen. This video shows the wrist on a serve of unknown type. It also shows, particularly clearly, the racket head motion from the Big L Position to impact.
To single frame on Vimeo, hold down the SHIFT KEY and use the ARROW KEYS.



I don't agree with this article in its use of the definition of flexion - there are two definitions of wrist flexion in use and that is often a confusing point.
FedererSnap.png

Flexion can be defined and used in two different ways:
1) as an angular position OR
2) as a direction of motion.
From a position of large angle wrist extension to a position smaller angle wrist extension is also called flexion. In the picture, Federer flexes his wrist in the example shown from larger extension angle (left) to smaller extension angle at impact (middle). Should that be called 'wrist snap'?

I estimate wrist extension by the angle between the back of the hand and the adjacent forearm surface.

I don't use the term 'wrist snap' but I have criticized the undefined use of it. I can see rapid flexion occurring in the Federer serve and also in this serve from the quoted post.

Click "V" & go full screen. This video shows the wrist on a serve of unknown type. It also shows, particularly clearly, the racket head motion from the Big L Position to impact.
To single frame on Vimeo, hold down the SHIFT KEY and use the ARROW KEYS.

I see the wrist rapidly flexing as the racket goes from horizontal to impact - large wrist extension angle to smaller wrist extension angle. That is rapid flexion. It could reasonably be called 'wrist snap'?
 
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Whoops!

I have to revise my views on the term 'wrist snap' during the tennis serve. Click expand to see correction.



Will edit more detail tomorrow.
It would make sense this is an element because wrist action is in the pro golf swing and baseball pitching motion too. One of the most common tips you'll see for people really struggling conceptually with their driver is to think of it as throwing the clubhead through impact. Swinging my own clubs now (gently of course) I can tell that wrist action when I think of throwing it through is also primarily dominant hand flexion.
 
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TennisCJC

Legend
I'm genuinely interested in feedback on my serve. During practice the other day, I threw away a few flat first serves, Tried to alternate wide/t placement but didn't end up perfect with placement. I started playing 4-5 years ago but has been since put in quite an effort to develop and therefore, obviously a lot more hours compared to the average rec. player. I consider myself somewhere around 4.5. During matchplay, max speed on first serves is around 100 mph and average usually around 82-83mph. To much flat serving kind of kills my arm so more often then not I play spin serves rather then bombs. Avg on second usually around 80-81 so not much of a difference.

All speeds measured in kmh and converted to mph with playsight, see example from yesterday below

What i'm looking for is "easy" tips on technique that actually can be adapted at a rec level to further improve.

Your serve is very good for playing 5 years. Only tip I have is you are bringing your back foot around a bit far when you slide up into the pinpoint stance. Most coaches will teach to keep the back foot behind the front foot instead of going so far to the right. You compensate for this by getting your shoulders back to create a stretch between your hips and shoulders which is good. Keeping the foot back gives you a better angle to contact for slice and kick serves. You should also get a bit more power too on 1st serves as the distance to contact will be greater. You should find a good coach and work with them for a few serve lessons.

Another thought is you talk about "flat serves". I am a big believer in hitting spin on all serves. Sampras and Federer hit between 2,000 and 2,500 rpm on their first serves on average and a lot more on their 2nd serve. I've watched Isner court side a few times and even Isner hits mostly spin 1st serves. I watched Roddick at USOpen and he consistently hit 120 mph serves that had enormous spin. You could easily see the ball bend in the air even though he was hitting 120 mph.
 

Chas Tennis

G.O.A.T.
The serve is more like a shot put than a throwing motion - Meike Babel is on board with that analogy and she could play a bit. But is it true? Dr. Mark Kovacs - a well renowned sports scientist and excellent tennis player - is one of the pioneers of this concept if I'm not mistaken, so I guess there is some basis.

..........................................................................................................................


The term Dr Kovacs uses is long axis rotation, where it all happens as part of one larger movement (including the shoulder). Now that I can understand.

I don't agree with information in this video.

One issue -

In particular, the shot put drill raises the upper arm higher than Todd Ellenbecker recommends in his video for the tennis serve "Rotator Cuff Injury". ATP servers limit how high the angle of the upper arm goes, as can be seen in high speed videos. Their ATP techniques appears to follow the Ellenbecker recommendation. I've posted on this issue many times. "Rotator Cuff Injury" video is available on Tennis Resources.

Many of the demos discussing the serve show the upper arm at too high an angle to the shoulder joint.

The shot put drill motion raises the upper arm at a higher angle than is safe for the serve. Does the shot put itself or its drill involve significant internal shoulder rotation?

WARNING - Internal Shoulder Rotation during the tennis serve - with the upper arm at that high an angle - is not recommended in the Ellenbecker video "Rotator Cuff Injury". Shot put?

This issue points out why the defined joint motions of internal shoulder rotation and pronation should be correctly used.
 
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Chas Tennis

G.O.A.T.
I don't agree with this. Since this is not correct, I hope that it will be removed from Youtube.

Pronation in simple terms: EXPLAINED
CC indicates closed captions on Youtube.
 
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dennis

Semi-Pro
This came up in my feed

I just had a look at a couple of recent Sabalenka serves. It looks like she does the post-release tossing arm twist as emphasised as so important in this video. It looks a lot more extreme than other players. Novak and Fed do it to a much lesser extent, Zverev hardly at all.
 

PKorda

Professional
I just had a look at a couple of recent Sabalenka serves. It looks like she does the post-release tossing arm twist as emphasised as so important in this video. It looks a lot more extreme than other players. Novak and Fed do it to a much lesser extent, Zverev hardly at all.
that was pretty interesting, gonna definitely look for this now when watching pro players and give it a try

btw, this is at the 19 min mark if anyone is interested and doesn't want to watch the whole video
 
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jmnk

Hall of Fame
I don't agree with this.

Pronation in simple terms: EXPLAINED
CC indicates closed captions on Youtube.
this is exactly why some may be good coaches, and can demonstrate things - but they can't explain it properly in words. He talks about 'wrist movement' and his demonstration clearly shows _no wrist movement_ whatsoever.
 

Chas Tennis

G.O.A.T.
More on

Sabalenka’s Technique Coach Gavin MacMillan​

This video is an earlier Youtube than the one in post #216.

CC brings up captions. My display had small print. I put the cursor on the captions and used the "+" key to enlarge the print.

Reference book that Gavin showed at the end of the earlier video in post #216.
Youtube here by the author, Serge Grocovetsky. A specialist in movements of the spine.
 
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tennis3

Hall of Fame
This serve video completely misses the significant part played by internal shoulder rotation (ISR) during the serve, as do most other serve instructional videos. Why is that?
In your opinion, HOW does a server get the shoulder to internally rotate? This is meant to be a practical question, meaning:
  • How do you get ISR?
  • Not in a general way
  • But in a way that creates the type of serve you want
  • Especially at high speeds

Do you have some ideas on what a server should be concentrating on to do this?

  • Should he be focusing on his shoulder and just trying to rotate it as fast as possible?
  • Should he be focusing on his wrist? His forearm? His elbow? His chest? His hip? Trying to rotate those as fast as possible?
  • And maybe by rotating one of these, there is some "kinetic chain" effect that creates (highly efficient) ISR?
  • Should he be rotating in an upwards / downwards / left / right / forwards direction?
  • Is there more than one force happening at the same time? Or is it just a single force? Moving in a single direction?
  • Is it a pushing motion? A pulling motion? What is being pushed or pulled? And how?

You post A LOT on WHAT HAPPENS. But I never see you post on HOW IT HAPPENS. Do you have some ideas?
 
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tennis3

Hall of Fame
this is exactly why some may be good coaches, and can demonstrate things - but they can't explain it properly in words. He talks about 'wrist movement' and his demonstration clearly shows _no wrist movement_ whatsoever.
Just because you don't see something "move" doesn't mean force isn't being applied either by the wrist or to the wrist. I often "aim the power" at the wrist (which is not the same as "swinging with the wrist").

What do you think is "really happening" in the mouratoglou video? You can easily see that the "racquet pronates" (I'm making this sound funny intentionally). You can easily see the speed and power. He's a very high level coach (so maybe don't dismiss him too fast?). So maybe he's on to something? But what exactly? Any desire to explain what you are seeing in the video? Or is it just "nonsense"?
 
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Chas Tennis

G.O.A.T.
In your opinion, HOW does a server get the shoulder to internally rotate? This is meant to be a practical question, meaning:
  • How do you get ISR?
  • Not in a general way
  • But in a way that creates the type of serve you want
  • Especially at high speeds

Do you have some ideas on what a server should be concentrating on to do this?

  • Should he be focusing on his shoulder and just trying to rotate it as fast as possible?
  • Should he be focusing on his wrist? His forearm? His elbow? His chest? His hip? Trying to rotate those as fast as possible?
  • And maybe by rotating one of these, there is some "kinetic chain" effect that creates (highly efficient) ISR?
  • Should he be rotating in an upwards / downwards / left / right / forwards direction?
  • Is there more than one force happening at the same time? Or is it just a single force? Moving in a single direction?
  • Is it a pushing motion? A pulling motion? What is being pushed or pulled? And how?

You post A LOT on WHAT HAPPENS. But I never see you post on HOW IT HAPPENS. Do you have some ideas?
"You post A LOT on WHAT HAPPENS. But I never see you post on HOW IT HAPPENS. Do you have some ideas?"

You are right about A LOT on WHAT HAPPENS. And I do say a lot about HOW IT HAPPENS and often mention muscles that are involved or may be involved.
Where I don't say much it's because I don't know anything worth contributing. That includes what you should think, feel, focus on. There are many ATP athletes that might be qualified to do that.

In 2011, on this forum I was shocked to learn about Internal Shoulder Rotation (ISR) and the serve. It had been missed in tennis research until 1995! I had been completely ignorant of ISR since the 1970s when I read books to learn about the serve.

In 2011, I became very interested in tennis stroke biomechanics. After being fooled for about 36 years, I decided that high speed video was a necessary ingredient for for determining what is true. In the last few years, I decided that sub-motions were clear and present in ATP strokes and that I was going to identify sub-motions in high speed videos. I found quite a few.

I'm not an instructor or a high level player. I'm old. I'm a tennis stroke analysist that studies high speed video of pro players.

My posts emphasize certain strokes and sub-motions. Many of my best posts were in the past when I studied & posted them. I can't rewrite them again and I search them myself all the time especially for their links and especially for the videos.

1) I went into detail with certain sub-motions of the serve about 2015 more or less. I start with the racket lowered and went to impact. Listed sub-motions observed in high speed videos.
2) Last 3-4 years, I added a thread on Thoracic Extension and the serve. Other stoke subjects have been posted.
3) I have a thread on the 1HBH that identifies many sub-motions.
4) I have threads & posts on the forehand that go through separation in detail.
5) Thread on Biomechanics.
6) Other threads on tennis topics and biomechanics.

I usually emphasize video frames as the source for communicating. Your post asks many general questions about many subjects. I have posted on many of those subjects mostly based on video observations of sub-motions. Too much time for me to rewrite and or search my posts & threads.


Forum search
Internal Shoulder Rotation Serve
Member: Chas Tennis

Google: (any tennis stroke subject) tennis Chas

Be glad to answer questions that you have once you have searched and found one of my posts or threads.

Please start a new thread or reply to the old thread.

Another approach that I suggest is to spend as long as it takes - hours - to look at one high speed video stroke video and understand each thing that I describe in the video. Read the text in posts. If you do not understand a term, Google it or ask a question.
 
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tennis3

Hall of Fame
Be glad to answer questions that you have once you have searched and found one of my posts or threads.
It's just not practical for me or anyone to search and research your old threads and try to tie all of your thoughts together. Have you ever tried to do it yourself?

Maybe a good idea for a new thread from you?

  • Here's what you want to do
  • Here's how you do it
  • Video analysis provided for both pieces
 
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dennis

Semi-Pro
More on

Sabalenka’s Technique Coach Gavin MacMillan​

This video is an earlier Youtube than the one in post #216.

CC brings up captions. My display had small print. I put the cursor on the captions and used the "+" key to enlarge the print.

Reference book that Gavin showed at the end of the earlier video in post #216.
Youtube here by the author, Serge Grocovetsky. A specialist in movements of the spine.
Do you have an opinion on tossing arm inversion and the "left scapula rolling over the shoulder and extending" as mentioned in that podcast?
 

Chas Tennis

G.O.A.T.
Do you have an opinion on tossing arm inversion and the "left scapula rolling over the shoulder and extending" as mentioned in that podcast?
Never heard of it for the tossing arm. My information was that the tossing arm should be brought down with force/acceleration and pulled in with timing to increase body bending with momentum from the arm. I thought I was seeing that in videos. I have not been clear on what is going on with that or Gavin's new point on how the tossing arm is oriented. Gavin's comments are interesting and I will listen to them carefully.

The video I posted (post #221) has some pictures of the arm inversion and more detailed discussion. (The closed captions blocked the lower hand position on the first video posted by @ratherlosethanpush. I tried to find that video without captions, no luck.)

When I get a chance, I'll do quick stats - look at ten good ATP servers and see how many do what Gavin describes. First, I need to understand what he said in terms of what I might see in the videos - and its limitations. High speed videos show the surface of the body and its positions, but the 2D video is limited in locating the body in 3D space. This limitation causes uncertainty that is tricky and maybe too uncertain for locating certain things such as the scapula on the body. Locating arms, legs, racket and ball works much better with good camera angles, but the inner body bones are harder to see in videos than arms and legs. Tennis clothes bouncing around also makes the scapula and deltoid area hard to locate.

A lot of Gavin's comments need interpretation. I hope the captions are correct.

The Scapula is one half of the shoulder joint. The Scapula moves around significantly on the body, so the shoulder joint does also. My old thought - that the shoulder is simply on the 'corner' of the body - is long gone.

The last hitting Scapular motion follows Thoracic Extension & other motions and their function in the serve. This final time of the serve before impact is the most complicated part of the serve. If anyone finds biomechanical analysis of these last milliseconds of the serve, please post them. Gavin had something to say about that too, see the medical video by Serge.

This video shows Thoracic Extension and Flexion plus other motions bringing the hitting Scapula into position for impact at 0 ms. If a picture is worth a thousand words, a video is worth a million. This video has a countdown timer where 0 milliseconds is nearest to the impact frame. Kinovea video analysis was used. Kinovea is free and open source and has many capabilities such as the countdown timer.
To single frame on Youtube, stop video, go full screen and use the period & comma keys.

It looks as if Benneteau is re-orienting his tossing arm and hand.........

SEARCHGAVIN
 
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dennis

Semi-Pro
Never heard of it for the tossing arm. My information was that the tossing arm should be brought down with force/acceleration and pulled in with timing to increase body bending with momentum from the arm. I thought I was seeing that in videos. I have not been clear on what is going on with that or Gavin's new point on how the tossing arm is oriented. Gavin's comments are interesting and I will listen to them carefully.

The video I posted (post #221) has some pictures of the arm inversion and more detailed discussion. (The closed captions blocked the lower hand position on the first video posted by @ratherlosethanpush. I tried to find that video without captions, no luck.)

When I get a chance, I'll do quick stats - look at ten good ATP servers and see how many do what Gavin describes. First, I need to understand what he said in terms of what I might see in the videos - and its limitations. High speed videos show the surface of the body and its positions, but the 2D video is limited in locating the body in 3D space. This limitation causes uncertainty that is tricky and maybe too uncertain for locating certain things such as the scapula on the body. Locating arms, legs, racket and ball works much better with good camera angles, but the inner body bones are harder to see in videos than arms and legs. Tennis clothes bouncing around also makes the scapula and deltoid area hard to locate.

A lot of Gavin's comments need interpretation. I hope the captions are correct.

The Scapula is one half of the shoulder joint. The Scapula moves around significantly on the body, so the shoulder joint does also. My old thought - that the shoulder is simply on the 'corner' of the body - is long gone.

The last hitting Scapular motion follows Thoracic Extension & other motions and their function in the serve. This final time of the serve before impact is the most complicated part of the serve. If anyone finds biomechanical analysis of these last milliseconds of the serve, please post them. Gavin had something to say about that too, see the medical video by Serge.

This video shows Thoracic Extension and Flexion plus other motions bringing the hitting Scapula into position for impact at 0 ms. If a picture is worth a thousand words, a video is worth a million. This video has a countdown timer where 0 milliseconds is nearest to the impact frame. Kinovea video analysis was used. Kinovea is free and open source and has many capabilities such as the countdown timer.
To single frame on Youtube, stop video, go full screen and use the period & comma keys.

It looks as if Benneteau is re-orienting his tossing arm and hand.........

SEARCHGAVIN
The video shows the 'tossing hand inversion' movement. Here you can see a pronounced turn in Rublev's serve:

Sabalenka 2024:

Sabalenka 2022 serve (later hand turn due to it being before the technique change, or simply a higher toss?).
 
I've never been taught to serve in tennis and could serve from day 1. I came to tennis when injury forced me out of other sports. I don't mind playing tennis badly, I object to playing the sports I used to play badly.

I did some serves today, so I paid attention and my arm inverts. You throw this way, you bowl this way, you pitch this way.

I think he's right tennis serving is essentially an overhead throw with an inclined plane, its not complicated. The continental grip with the racket affects how you need to aim and this puts the serving shoulder behind at impact. With a waiters tray serve the serving shoulder is not behind.
 

Chas Tennis

G.O.A.T.
I see the wrist/hand turn and the arm straight. It is important to determine both the ISR and the Pronation of that hand turn.

But when the arm is straight both Internal Shoulder Rotation (ISR) and Pronation cause the hand to rotate in the same way. (real defined Pronation not ignorant tennis PronaTion) Remember Pronation and ISR add for hand turning when the elbow is straight or near straight.

Find very sharp videos that show some shadows (bone & tendon) at the elbow. The shadows turn with the humerus and indicate ISR. But the shadows don't turn with the Pronation. It is still hard to separate the Pronation.

Is it Pronation, ISR or a combination of both?

Gavin was stating some consequences of not doing this tossing arm motion correctly. (I do not get that yet.)
 
I see the wrist/hand turn and the arm straight. It is important to determine both the ISR and the Pronation of that hand turn.

But when the arm is straight both Internal Shoulder Rotation (ISR) and Pronation cause the hand to rotate in the same way. (real defined Pronation not ignorant tennis PronaTion) Remember Pronation and ISR add for hand turning when the elbow is straight or near straight.

Find very sharp videos that show some shadows (bone & tendon) at the elbow. The shadows turn with the humerus and indicate ISR. But the shadows don't turn with the Pronation. It is still hard to separate the Pronation.

Is it Pronation, ISR or a combination of both?

Gavin was stating some consequences of not doing this tossing arm motion correctly. (I do not get that yet.)
You can't tell, digitising 3d images won't work.

The motion can be caused by both.

If you want to know if the muscle is active, you need to measure the electrical impulse.

At least it was that way however many decades ago it was since I studied sports science.

Not many elite athletes like you shoving needles in to check that, plus the needles themselves may arguably change motion.
 

Dragy

Legend
You can't tell, digitising 3d images won't work.

The motion can be caused by both.

If you want to know if the muscle is active, you need to measure the electrical impulse.

At least it was that way however many decades ago it was since I studied sports science.

Not many elite athletes like you shoving needles in to check that, plus the needles themselves may arguably change motion.
There are some general ideas which are very unlikely to be broken in efficient athletic motions. Namely, with straight arm ISR and pronation work in same direction. Which means accelerated ISR puts load on forearm twisting. Consequently, if you tried to pronate during ISR accelerated phase, you would need to overcome the torque from ISR and add something on top of that. Not good idea when trying to max out on the speed.

What is obviously most efficient is to let forearm stay stretched into full supination and only do pronation when ISR is starting to slow down.

Why is it practically important? Because you want to feel forearm as relaxed, while tight forearm will indicate inefficiency and power leak.
 

Digital Atheist

Hall of Fame
Gavin was stating some consequences of not doing this tossing arm motion correctly. (I do not get that yet.)
It would appear to me that, while this is probably good advice, it is somewhat stylistic since not all top level servers execute this move; there appears to be variations, ranging from no turn to very little to quite pronounced.



You could argue Sampras turns his hand slightly (since he starts with the palm under the ball), but barely. Hurkacz, one of the best servers on tour at the moment, doesn't do this either:

Korda:

Whereas Kyrgios and Medvedev (in addition to the others mentioned) both have reasonably pronounced hand turns. So I don't really know.
 

Chas Tennis

G.O.A.T.
The video shows the 'tossing hand inversion' movement. Here you can see a pronounced turn in Rublev's serve:

Sabalenka 2024:

Sabalenka 2022 serve (later hand turn due to it being before the technique change, or simply a higher toss?).

Those show it.

If you find serves that don't, let's get an idea of the percentages.

Great find!
 
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Chas Tennis

G.O.A.T.
We should look at what precedes this tossing hand turn and what follows it.

If I take my hand up with the tossing release orientation and a straight arm, I feel tightness develop. ? Turn wrist and less tightness?
 
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Chas Tennis

G.O.A.T.
You can't tell, digitising 3d images won't work.

The motion can be caused by both.

If you want to know if the muscle is active, you need to measure the electrical impulse.

At least it was that way however many decades ago it was since I studied sports science.

Not many elite athletes like you shoving needles in to check that, plus the needles themselves may arguably change motion.
Since ISR turns the entire forearm, when the arm is near straight -

Observed hand turn = ISR + Pronation

Observed hand turn - wrist watch or other non-slip wrist band could indicate with calibration procedure after serve. Probably accurate.

The elbow shadows indicate ISR - Accuracy finding videos on the internet using sun shadows, not good. Can't calibrate. Accuracy potential with a cooperating server and calibration procedures. ?

(One should keep in mind that the original measurements of ISR on the serve were questioned because the 3D Motion Capture System techniques used had an error source due to reflective balls on arm surface that lagged behind the Humerus bone ISR. I am not familiar with the best available accuracy for ISR measurements now.)
 
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Chas Tennis

G.O.A.T.

To check what Gavin really said - This link has a transcript of what was said in the video.

Click on "Youtube" then "more" and find "Show Transcript"

I have found that also playing the captions when Youtube plays is pretty good. To enlarge captions on Youtube, click on caption and use cntrl and the "+" key.

Maybe playing Youtube - with sound off - so that the captions are slow is the best way to read what he said about what the 'inversion' is doing would be good.

Please post times of the comments in all videos to help us find them.
 
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Chas Tennis

G.O.A.T.
It would appear to me that, while this is probably good advice, it is somewhat stylistic since not all top level servers execute this move; there appears to be variations, ranging from no turn to very little to quite pronounced.



You could argue Sampras turns his hand slightly (since he starts with the palm under the ball), but barely. Hurkacz, one of the best servers on tour at the moment, doesn't do this either:

Korda:

Whereas Kyrgios and Medvedev (in addition to the others mentioned) both have reasonably pronounced hand turns. So I don't really know.
I see Sampras turns his tossing hand, 25-30 sec, and Hurcacz turn his hand,15-21 sec.
 
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Chas Tennis

G.O.A.T.
It would appear to me that, while this is probably good advice, it is somewhat stylistic since not all top level servers execute this move; there appears to be variations, ranging from no turn to very little to quite pronounced.
...........................
To single frame on Youtube, stop video, go full screen, use the period & comma keys.

This Sampras video has some very good camera angles for the tossing arm. It also shows the uses of the tossing arm to accelerate rapidly downward from its raised position and then be pulled in. This precedes the shoulder-over-shoulder motion where the hitting shoulder starts low and the tossing shoulder starts high. Motion blur can be used as an indication of speed, blurry objects are moving faster. The arm gets blurry when pulled down. The hand becomes sharp again at some point.

See the hand turn, the arm accelerate down and then the elbow bend and pull in. ?

For example, click Full Video. See 25 sec. Interesting high camera angle that I don't recall seeing before at 3:05.

Does this motion assist the shoulder-over-shoulder serve motion when the arm is pulled in? And the hand turn makes that work better, somehow.? The upper body is turning ......very busy part of the serve in hardly any time.

Time to study what Gavin had to say.....

Thanks for finding and posting @Digital Atheist
 
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enishi1357

Semi-Pro
I explored this. I came to one technique that made the biggest difference. What makes this so good is it works with momentum gravity. It's also so simple it's like duh why didn't I thought of it.
 

Digital Atheist

Hall of Fame
To single frame on Youtube use the period & comma keys.

This Sampras video has some very good camera angles for the tossing arm. It also shows the uses of the tossing arm to accelerate rapidly downward from its raised position and then be pulled in. This precedes the shoulder-over-shoulder motion where the hitting shoulder starts low and the tossing shoulder starts high. Motion blur can be used as an indication of speed, blurry objects are moving faster. The arm gets blurry when pulled down. The hand becomes sharp again at some point.

See the hand turn, the arm accelerate down and then the elbow bend and pull in. ?

For example, click Full Video. See 25 sec. Interesting high camera angle that I don't recall seeing before at 3:05.

Does this motion assist the shoulder-over-shoulder serve motion when the arm is pulled in? And the hand turn makes that work better somehow.? The upper body is turning ......very busy part of the serve in hardly any time.

Time to study what Gavin had to say.....

Thanks for finding and posting @Digital Atheist
You're right about Hurkacz. Here is one showing quite a pronounced turn.
 

dennis

Semi-Pro
Time to study what Gavin had to say.....
He mentions three technical changes:

1. Tossing arm 'on the wrong side of the head'. I believe this means too far to the left for right handed players.
2. Tossing hand inversion.*
3. Tossing arm stretching out towards the net as it comes down. I assume he means doing this for too long before bending and tucking into the body.

* Sabalenka now has the most extreme and early version of this on tour? As much as Gavin dismisses the psychological side, I wouldn't be surprised if the focus on turning the hand helps her mentally. It could be like a reassuring checkpoint.
 
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Chas Tennis

G.O.A.T.
He mentions three technical changes:

1. Tossing arm 'on the wrong side of the head'. I believe this means too far to the left for right handed players.
2. Tossing hand inversion.*
3. Tossing arm stretching out towards the net as it comes down. I assume he means doing this for too long before bending and tucking into the body.

* Sabalenka now has the most extreme and early version of this on tour? As much as Gavin dismisses the psychological side, I wouldn't be surprised if the focus on turning the hand helps her mentally. It could be like a reassuring checkpoint.

We should look at the alignment of the tossing arm, the line between the two shoulders (shoulder girdle) and the hitting shoulder and its humerus, as this is being done. From above cameras, if they appear in line, that may be important. ?

This starts first playback at 3:02 on a rare high camera angle for just this one video clip. I don't recall ever seeing this camera angle before.
To single frame on Youtube, stop video, go full screen and use the period & comma keys.

Note motion blur of tossing arm and hand. When the tossing hand becomes free of motion blur, it has slowed down or stopped relative to the camera.

This video clip shows the tossing arm - in addition to going down - is also going back relative to Sampras's body. That backward component of tossing arm momentum might aid the turning of the uppermost body when stopped. The arm is sped up with momentum directed down & back. Later it is pulled in and stopped. If the tossing arm's momentum is transferred to the uppermost body it might add to shoulder-over-shoulder and uppermost body turn. Needs work and more observations....

Gavin discusses in Podcast #82 video the tossing arm at 3:32 and shows a Roddick serve with his use of the tossing arm. 5:41 Captions on are helpful. This video was a year earlier than the recent video posted by @ratherlosethanpush, #216.

An above camera view would best display the backward component of the tossing arm's velocity.
 
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Chas Tennis

G.O.A.T.
Good angle of Thiem's serve here.
Nice find. Some elbow shadows show ISR is being used.

Speculating, this ISR might be to orient the elbow so that it can flex at the right time and place. ? See pull-in of tossing arm. In principle, this pull-in is similar to how an ice skater pulls in her arms and leg to transfer momentum for her spin up.

Maybe an above camera view would show this more completely?

Frank Salazar, Fuzzy Yellow Balls overhead video.

Slice serve. See tossing arm motions.
To single frame on Youtube, stop video, go full screen, and use the period & comma keys.

Flat serve.

______________________________________________________________________________________________________
For the three main types of serves.

Kick Serve. Stop on the frame of impact and look at the ball and head positions.
Note - 'For the kick serve - toss the ball over your head.' IS NOT TRUE

For the kick serve - toss the ball and move your head forward to impact the ball over your new head position. IS TRUE

Set all 3 type serves on impacts and note the positions of the ball, head, angle of the hitting arm and racket at impacts, angle of the chest.


Too bad there are not more overhead camera views in college tennis training.
 
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Chas Tennis

G.O.A.T.
To understand the serve and Internal Shoulder Rotation in videos from start to impact, you need to observe
BDE03643A2A04DE588FB7EE49E554F3F.jpg


F1B3645CA0B443EDBF4C4EF8529B76CE.jpg


360133EA760942C9AECB7086E10EC153.jpg


B0412C400FA24351BE85DB8D5CE4D993.jpg


968B284E561847409B6EF37604C10C3D.jpg

For a slice serve at impact - when viewed by a camera from behind- the arm tilts right and the racket tilts left.


F65CB827E69442A7B56DAF71B8A25E56.jpg


Frames from 240 fps video recording.
 
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Chas Tennis

G.O.A.T.
This earlier forum post by @Digital Atheist has a very nice display of ISR from start to impact, by Kyrgios. See especially the changing forearm-to-racket-shaft angle at the wrist. Without that angle ISR (or pronation) does not result in racket head speed, the racket head just spins.
I have a question on this to do with what is often called "full" pronation, when the racquet is turned out completely and the hitting side of the strings face to the side (as in the Karlovic thumbnail above). I understand that term is technically incorrect, but it is often referenced as such (TTT for example).

But just how important is this position to a big serve? Nick from intuitive tennis says it is overrated and shouldn't be a major focus. I see Nick Kyrgios has very little turning out of the racquet, on first serves in particular, and the dude hits bombs that are still smoking when they come off the back wall. Obviously he is still getting plenty of ISR for that kind of power generation, but he doesn't seem to allow his forearm to turn naturally with the shoulder. Here is a slowmo of one serve, which can be frame advanced to see what I mean.


Taken from: youtube.com/watch?v=Z_LU2q1CROA

And there are plenty more there. Thoughts?
You can stop the video and hold down the period & comma keys with the index finger to go back and forth over just the ISR phase of the serve. This is one of the clearer displays of the speed of ISR. Ask yourself what body part in the video is moving fastest for impact? You can also see why this twitch-like motion might have been missed by early tennis researchers for decades, until 1995!

Fully pronated is in the follow through and servers do not have to do it because they can slow down in a variety of ways. If you look at high speed videos you will find some high level serves that do not get to 'fully pronated'. In other words, nothing specific after impact - like 'fully pronated' - is necessary to impact the ball effectively. Still, many ATP servers do get to 'fully pronated'.
 
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