Kinovea Analysis of an Unknown Serving Technique

[Chas Tennis]

There is the Waiter's Tray Serve used by the majority of active tennis players and the high level serve used by the ATP & WTA? and some other hardly known DIY techniques. What other technique is there?

One of the other techniques that I found while analyzing forum serves was a serve that used ISR for significant racket head speed but was not an ATP technique or a Waiter's Tray, although sometimes the racket face faced the sky (a test for likely Waiter's Tray). It was difficult to identify what was going on and took me a year. ? I finally used a display method where the video was played Forth & Back, Forth & Back..... It seemed to help noticing serve positions and also remembering what you had seen (from the repetitions?) You could also shift from one sub-motion to the next.

Here is a side-by-side Kinovea comparison of a forum poster and an ATP server, with millisecond count down timer to impact and another to show time after impact. The comparison was not ideal - flat to slice serve, different camera angles, and other things that could be selected for more accurate future comparisons. The single frame advance skips sometime but we can count on the millisecond timers. Time 0 is closest to impacts. Example, - 4 is 4 milliseconds before impact. +5 is 5 milliseconds after impact. If you put a millisecond time line on a serve video all sub-motions could easily be timed.

Kinovea video analysis to created this comparison.

You need these instructions when looking at the video-
Forth & Back - start video and stop it_ drag white time indicator Forth & Back, Forth & Back....... Vary the speed, and the range of frames viewed. This is not so tough, you can do it!

After you get the hang of Forth & Back, go full screen. Observe and look for differences between the two serves. Isolate sub-motions.

OR_ best for 1 & 2 below _ to single frame on Vimeo, hold down the SHIFT KEY and use the ARROW KEYS.

1) Find the orange lines at impacts that show the long axis of the upper arm. What differences can you notice about those lines for each server (not perfect)?
2) Examine the racket faces going up to impact. What differences can you notice there for each server ?

Careful now, you are analyzing the heart of the tennis serve, its fastest motions and a second unknown technique that is so difficult that some tennis experts could not observe it without these secret instructions?

Have you observed any differences after half an hour?

I can answer a few questions, but all you need to do is observe differences - in a few frames of video.

I'll post some analysis of the serves later.

 

[Kevo]

The toss is farther to the right allowing the shoulder tilt to be less aggressive, but in order to get the strings to face the target the grip had to be shifted off continental slightly. Nothing to worrisome from my point of view, and depending on the goals of this particular player and their physical abilities I would not be inclined to "correct" the technique if it's working for them in match play. I would like to see how well they manage second serves though. That might change my opinion on whether technique changes might be warranted.

Also...

Toss is the BOSS!!!

( Had to do it. )

 

[Chas Tennis]

The toss is farther to the right allowing the shoulder tilt to be less aggressive, but in order to get the strings to face the target the grip had to be shifted off continental slightly. Nothing to worrisome from my point of view, and depending on the goals of this particular player and their physical abilities I would not be inclined to "correct" the technique if it's working for them in match play. I would like to see how well they manage second serves though. That might change my opinion on whether technique changes might be warranted.

Also...

Toss is the BOSS!!!

( Had to do it. )

Did the instructions work well for Forth & Back?

There were 2 questions about the orange lines and the racket faces.

See the latest edited version.

 

[Kevo]

I thought the line difference was obvious. One is more vertical, hence my comment about shoulder tilt, which is forced by that toss location. As for the racquet faces, there are more nuances involved as these are two different serves with different intentions. The forum server has their racquet face opening up during the swing, but that also is being forced by the toss location. Of course I'm not sure which came first, the "poor" grip choice or the toss location, but he can't "fix" that problem if he's consistently tossing the ball that far to the right for a flat serve. I'd be really curious to see that forum poster's slice and kick serves if he has them.

If I'm not answering your questions correctly feel free to give me low marks.