How exactly does pronation help for a top spin serve?
- Thread starter yescomeon
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Chas Tennis
G.O.A.T.
This stuff is a little preliminary and needs some more videos of serves of known type.
The racket is near its highest point and it goes to the side, hardly rising. The spin axis could be closer to vertical. See the text in reply #55. Look at impact with the ball squished. Then look at the racket in the frame after impact. Reference the location of the top of the racket to the baseline in the background - it hardly rises.
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arche3
Banned
This stuff is a little preliminary and needs some more videos of serves of known type.
The racket is near its highest point and it goes to the side, hardly rising. The spin axis could be closer to vertical. See the text in reply #55. Look at impact with the ball squished. Then look at the racket in the frame after impact. Reference the location of the top of the racket to the baseline in the background - it hardly rises.
So it is definitely the leftward momentum at impact which makes the ball turn left after the bounce, while for the kick, the rightward momentum does the opposite. And the spin direction being the same for both cases, they both move left in the air. Very good.
tennis_ocd
Hall of Fame
That's my take. From server's pov, right to left like a tilted banana. Ideally, TS causes the ball to vertically dive to court and bounce high (higher than a linear, flat ball.) Side spin component will cause bounce to jump to right (server pov.)
Do it like Isner and (returner pov) the ball your mind is tracking to right-side fh, waist high is suddenly up at your left ear and rising.
tennis_ocd
Hall of Fame
hmmm. Assuming basics (conti grip; pronation being the outward turning of the racket from edge to face to opposite edge) how does the racket face get aligned to the ball? All serves start edge on. If there was no pronation prior to impact we'd be hitting with the frame edge.
Only if the edge was exactly right on to the ball. If not, you would not need to move it.
tennis_ocd
Hall of Fame
To me, Stosur clearly comes up to the ball edge on and begins to pronate prior to strike.
Yes she does. I think most pros do.
Chas Tennis
G.O.A.T.
Pronation is a joint motion that rotates the forearm/wrist.
Internal shoulder rotation is a shoulder joint motion that rotates the upper arm, and, therefore, the entire arm.
You can Google these terms for joint motions.
When the arm is straight both pronation or internal shoulder rotation produce the identical rotation of the forearm and wrist.
Demo - Bend your elbow at 90 d. Rotate the forearm/wrist in each direction to see pronation and supination.
Now hold your arm straight out from the shoulder with your arm straight. Rotate from the shoulder. That's internal shoulder rotation Try doing pronation and internal shoulder rotation separately. It might help to hold the elbow still with your free hand when you try to do pronation. Put a racket in your hand and examine how rotating the entire arm causes it to go edge-on to face-on orientations.
Upper arm bone rotates it's internal shoulder rotation.
If only the elbow down rotates it's pronation.
In years past, tennis players did not make the distinction and, by mistake, started calling the joint motion on the serve "pronation". Since this is very important for understanding how the racket is accelerated to the ball, it's now become important to use the correct terms.
Large muscles are attached to the upper arm bone for internal shoulder rotation. Small muscles are in the forearm for pronation.
Use TW Search box with "Show Posts" above: internal shoulder rotation Chas Tennis
Finds more discussions and many illustrations.
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tennis_ocd
Hall of Fame
Interesting. This somewhat refines my definition of pronation. If one breaks down identical wrist/racket face motion into subcategories of pronation vs. ISR or a mixture of both it... well, might change something.
So Stosur may open the racket face by ISR prior to impact.
I don't recall the term ISR being used by any of the youtube or literature experts on the serve (most do mention pronation) but anatomically speaking, you appear to be correct.
Here's to this new found knowledge - pronation, ISR... whale and elephants, getting me into the all-inclusive ttw 125 mph serve club.
Chas Tennis
G.O.A.T.
As best I can determine this entered tennis about in 1995 with publications by B. Elliott et al. I was stunned to learn it here in 2011. I had looked up pronation and practiced it in the 1980s before anybody understood this issue. Pronation can do edge-on to face-on, it's just not what the high level servers are doing.........
Here is a more recent summary, Biomechanics and Tennis
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2577481/
spacediver
Hall of Fame
Chas, have you seen Brian Gordon's fantastic four part serve biomechanic series on tennisplayer.net?
I don't think teaching pros really distinguish between ISR and Pronation.. Since your shoulder internally rotates as a trigger to the pronation - its really not such an important distinction..
http://www.feeltennis.net/serve-pronation/
I suppose you could argue these are mostly internal rotation drills and not pronation drills. If you could some how lock your elbow in place and not internally rotate you shoulder - you wouldn't get much power..but so what..
Learning how to use this 'rotational' force in your serve adds lots more power.. That's the key takeaway..
http://www.feeltennis.net/serve-pronation/
I suppose you could argue these are mostly internal rotation drills and not pronation drills. If you could some how lock your elbow in place and not internally rotate you shoulder - you wouldn't get much power..but so what..
Learning how to use this 'rotational' force in your serve adds lots more power.. That's the key takeaway..
Chas Tennis
G.O.A.T.
As a matter of fact, I just started reading some of that Brian Gordon information. Did you have something specific in mind?
spacediver
Hall of Fame
I remember going through the entire four part series, with the interactive applet. One of the best biomechanical breakdowns of the serve, imo.
These are the ones in particular:
The Serve Backswing: Part 1
3D Tennis: The Serve Backswing: Part 2
The Serve in 3D: The Upward Swing Part 1
The Serve in 3D: The Upward Swing Part 2
In fact, it's the main reason I renewed my membership there, although I haven't done so for the last few years, since $99 is steep just for access to that particular series
Anyway, just thought you'd appreciate the level of analysis.
These are the ones in particular:
The Serve Backswing: Part 1
3D Tennis: The Serve Backswing: Part 2
The Serve in 3D: The Upward Swing Part 1
The Serve in 3D: The Upward Swing Part 2
In fact, it's the main reason I renewed my membership there, although I haven't done so for the last few years, since $99 is steep just for access to that particular series
Anyway, just thought you'd appreciate the level of analysis.
spacediver
Hall of Fame
I made a thread a few years ago illustrating with 3d models what the difference between internal shoulder rotation and pronation is, and how leverage plays a role in generating racquet head speed. I think it's worth a look 3 years later.
http://tt.tennis-warehouse.com/showthread.php?t=370826
http://tt.tennis-warehouse.com/showthread.php?t=370826
VamosBamos987
Hall of Fame
Hey Legit question why did his serve at 0:20 fly long. I often have the same problem when attempting a topspin serve.
It was late winter, probably 3rd tennis day of the YEAR. Like, 4 months, THREE tennis days.
VamosBamos987
Hall of Fame
I'm asking the mechanical reason. It's ok man, relax and chill with the ego.
