Upperbody Orientation on the Serve Types - Flat and Slice vs Kick

Chas Tennis

G.O.A.T.
I have looked carefully at tennis videos of strokes for years and missed things in front of my face. Once these things are noticed, I always notice them after that.

Over the last year, I've been paying more attention to the orientation of the chest on the kick serve and noticed that the upperbody orientation was very different. I recently posted one of Toly's videos comparing a kick serve to a flat serve. It showed the difference of, say, the chest orientations and body tilt especially clearly. These images must have been seen many times before in separate videos and pictures but has it ever been noticed or discussed?

Of course, the issue of the variations of the upperbody orientations have to be studied for additional servers.

The thumbnail for this video shows the differences between the kick and flat serves. The frame at impact is a good time for comparisons of the chest and upperbody orientations and other angles.

Stosur's kick serve for comparison to Federer's. Note Stosur's head on side, the tilt of the arm, upper body tilt and chest orientation, racket shaft/face tilt at impact. Compare thumbnails to Federer's kick for similarity.

Some players like Stosur use the head on side technique and others like Federer do not.

There are not many pictures and videos from the side view so that the racket face is caught like these, one racket edge behind the other. That shows the racket tilt just before impact for the kick serve.

IIlustration of the racket closed tilt for the kick serve. Toly processed videos.

The racket is caught so that one edge is behind the other edge and the kick serve closed tilt is clear. This, however, is when the ball is squished in the strings, so a before touch position would be better. (Just take a few extra 240 fps videos to catch the ball near touching the strings.)

This Federer serve was identified as a kick serve. The bounce to the right was not verified by a second camera.

Notice that both Federer's and Stosur's arm, racket shaft and racket face are all observed at a tilted angle from this special side camera view where one racket edge blocks the other.
The point of this thread is to bring attention to the body orientation and other angles of the kick serve in comparison to the flat or slice serves. These angles show well from a certain camera side viewing angle.

How is the chest/ upper body of the kick serve orientated vs the flat and slice serves?
 
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SystemicAnomaly

Talk Tennis Guru
Hardly a revelation or novel idea. Any decent, or even half-decent, coach will tell you that kick serves, topspin serves or topslice serves will be hit significantly more "side on" than flat serves.

For the flat serve, the torso/body is uncoiled toward the net at contact. For kick serves or any topspin variations, the torso / body does not uncoil toward the net as much at contact. Instead the chest & and hitting shoulder uncoil upward (toward the sky) moreso than it does for flat serves. On these serves, the body will turn toward the net a bit after contact.
 
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Chas Tennis

G.O.A.T.
Hardly a revelation or novel idea. Any decent, or even half-decent, coach will tell you that kick serves, topspin serves or topslice serves will be hit significantly more "side on" than flat serves.

For the flat serve, the torso/body is uncoiled toward the net at contact. For kick serves or any topspin variations, the torso / body does not uncoil toward the net as much in contact. Instead the chest & and hitting shoulder uncoil upward (toward the sky) moreso than it does for flat serves. On these serves, the body will turn toward the net a bit after contact.
It is challenging to describe Stosur's and Federer's chest orientation in words. It has been done in the forum for 16 years, but has it worked? Maybe it does not communicate to the readers on the kick serve?

I see Stosur's and Federer's chest as more sideways and in addition much more tilted. Tilted refers to the direction of the rotation axis for torso/body coiling. The direction is clear in images but usually not communicated in words. A coach may make that clear while teaching.

There may be other chest orientations in use for the kick serve. ?

As a coach with your experience, the Federer and Stosur pictures may be what you expected to see, but for many readers the side-by-side comparison of Gulbis and Federer might be surprising, as it was for me.

Both Federer and Stosur look 'sideways' but the camera does not show and shrinks the locations of chest or back points toward and away from the camera - the 2D image of 3D space problem. See demo. That makes estimating angles very inaccurate. An above camera view is better to estimate the chest angle to the ad or deuce sidelines. We do have the overhead Salazar kick serve that shows his chest at about 45 degrees to the sideline at impact. But I don't think that Salazar's chest was tilted as horizontally as Stosur's. ?

Assuming that the rotation axis of Stosur's uppermost body is about aligned with the neck axis, I estimate with a protractor that the angle of that neck axis to the horizontal is 30 degrees, closer to horizontal than to vertical. How typical is Stosur's kick serve? It's close to Federer's in the above two videos.


( Demo. For those that did not follow the above, here is a demo. Take a paper clip and straighten it. Put a 135 degree bend in it. Hold one end vertically and rotate the paper clip. Estimate the angle that you see at arm's length. It appears to go from 180 degrees to 135 degrees - that's the 2D image of 3D space problem for estimating angles. The location of points toward or away from your eye is shrunken or hidden. Always remember this when you make estimates from images. )
 
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Dragy

Legend
Torso orientation and arm position on any good serve is mostly this approaching contact:

The difference is determined by “throw” direction:
- Higher than a pitch for all tennis serves, varying from like 60 deg up for power slice serves to closer to 80 for kick serves;
- Diagonal to intended target for the ball, varying from barely across for flat serve to 45 (?) deg for kick or spinny slice.

There are minor adjustments applied for different serves, but other from that it’s basically a throw-like orientation according to swing direction.
 

Dragy

Legend
Does that pitcher have the Gulbis or Federer orientation?
If you ask - none of them. His throw is more or less horizontal. Gulbis and Federer “throws” are both upward, though at different angles/directions. Their torso orientation is corresponding their “throw” direction. Try to wrap your mind around this.
 

Chas Tennis

G.O.A.T.
My opinion is that it’s not that useful to worry about what angle my torso is in. I just try to make the racquet move in the path I want, and the torso usually does what it needs to (at least it used to until my back started to get stiffer).
How do you know "the path I want"?

It is useful for those that want feedback on what they are doing. Once an established technique is in use the pro players will usually all go to similar positions vs time with interesting variations to be discovered. I only intend to observe ATP and WTA players with stronger strokes. I'm still seeing new stuff as in this thread.

When forum posters ask to have stroke videos analyzed, there is almost always a list of differences between their positions vs time and the pros. They can consider the list and decide what to do. A few posters look close to the pro techniques and need better videos and direct comparisons to try and see more detailed differences.

When I see fundamental problems such as not turning the uppermost body back and then forward enough with separation on ground strokes, that needs a rework of the basic technique and I only list that. If they can fix that then maybe other differences would be gone or could be changed next.

Does the path you want on the kick serve end with the racket tilted closed about 15 degrees just before impact? If we knew that the chest was always tilted a certain way for the pros, and you thought that was feasible for you, you could decide what to do.
 

travlerajm

G.O.A.T.
How do you know "the path I want"?

It is useful for those that want feedback on what they are doing. Once an established technique is in use the pro players will usually all go to similar positions vs time with interesting variations to be discovered. I only intend to observe ATP and WTA players with stronger strokes. I'm still seeing new stuff as in this thread.

When forum posters ask to have stroke videos analyzed, there is almost always a list of differences between their positions vs time and the pros. They can consider the list and decide what to do. A few posters look close to the pro techniques and need better videos and direct comparisons to try and see more detailed differences.

When I see fundamental problems such as not turning the uppermost body back and then forward enough with separation on ground strokes, that needs a rework of the basic technique and I only list that. If they can fix that then maybe other differences would be gone or could be changed next.

Does the path you want on the kick serve end with the racket tilted closed about 15 degrees just before impact? If we knew that the chest was always tilted a certain way for the pros, and you thought that was feasible for you, you could decide what to do.
I confess that there are times when I think I am arching my back like Pete, but then I see myself on video and realize that my back didn’t do what I told it to.
 
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