Have a Question for Me?

[johnyandell]

I think we are agreed.

[stotty]

John did you ever get an update on Tiafoe's serve? I was just wondering if his coach ever managed to resolve that peculiar ball toss he had?

[johnyandell]

Haven't seen him since... I won't say what my guess is...

[seano]

Serve

John -
Lately I have been studying the works of Dr. Bruce Elliott and Dr. Mark Kovacs. Going through their different stages for the serve. From loading the back hip to different trunk axis etc. What are your thoughts on their work?
Sean

[johnyandell]

To be honest I haven't looked closely enough. There is biomechanical research and then their is practice.
I tend toward the later. For example when you look at the serve the "research" shows that the movement of the wrist on the way up contributes to racket speed--now that's interesting. But the question is how does that happen?
Do you have a link to Mark's work on this?

[seano]

Tennis ICoach

John -

I've been watching these seminars from Elliott & Kovacs on the ITF website Tennis ICoach, taken from ITF conferences around the world.

Sean

[johnyandell]

God those things are like slow death on the web...little better in person...

[seano]

Serve - Kovacs/Elliott - your opinion

John -

In the loading phase of the serve -

Dr. Kovacs stresses the rear hip twisting around and down, more than shoulder turn. This engages the rear leg more, so when you explode you go up and into the court. With knee bend only, you just explode straight up and will end up "open" at impact.

Dr. Elliott stresses separation angle of hips/shoulders, where the shoulders turns more than the hips. Then as you explode up, you accelerate the rear hip faster than the front, leading to hip over hip, shoulder over shoulder.

Thoughts? This is for my knowledge, not getting too technical with students.

Sean

[johnyandell]

Sean,

Well from observation I have always believed that the greater rotation had to be key: McEnroe, Sampras, Fed...

But you can educate me. How does what those guys say relate to this:

http://www.tennisplayer.net/members/avancedtennis/john_yandell/sampras_serve/sampras_serve_hip_and_shoulder_rotation/

I guess the one other point I need to clarify in my own thinking--how the position of the back hip relates to foot position in the stances--and how the platform versus pinpoint effects this.

[seano]

Serve - Kovacs/Elliott - your opinion con't

John -

As always i'm fascinated by the work you discuss on Tennisplayer. The serve, especially, is such a complex and confusing subject. My take on the works of Dr's Gordon, Elliott & Kovacs, as well as, the 2 articles by Chas Stumpfel is that they're all describing the same complex lead up to all important internal shoulder rotation, just in different ways.

The Pete Sampras article with Dr. Gordon's research is very confusing but after much thought, follows the basic outline that all of the experts are describing. Sampras definitely rotates his rear hip back and down like Kovacs describes. With his rear hip lower in the loading phase, he then can accelerates it faster than the front which leads to what Elliott describes. Then that leads to hip over hip, shoulder over shoulder (they all discuss this). I would say this is when Sampras has greater shoulder turn than hip.

The trunk twist is the next phase and would cause the shoulders to go back to less separation, like you talk about in the Sampras article. Leading to the lateral tilt and the completion of external shoulder rotation. At this point, the extent of internal shoulder rotation is all pre-determined as you go up to contact then deceleration.

Dr. Elliott's talk about the 3 Trunk Axis (1)Twist, 2) shoulder over shoulder, 3) forward tilt) turned a light bulb on for me and it hopefully, cleared some confusion. Dr. Kovacs rear leg engagment with the rear hip rotating around and down, makes sense to create more ground reaction force.

Rear foot placement varies between platform and pinpoint, but seems to be personal preference. As long as the rear hip stays coiled and doesn't open. Separating ball toss and racquet lag may lead more to pinpoint but the rear foot being parallel to the baseline (like Rick Macci wants) is critical for either style.

Just some thoughts, not sure if it make sense but i'm fascinated by the learning process. Keep up the great work.

Sean

[johnyandell]

Sean,
You are educating us!

[gzhpcu]

John, a question about racket shaft - arm alignment. As the arm rotates counterclockwise coming up from the drop towards the impact point, the racket is a bit like a propeller, rotating around the arm axis. If shortly prior to impact the racket shaft and the arm are aligned, the racket head speed is lower than if an angle exists. The angle also facilitates the hitting across the ball, left to right. Also you get more leverage. You lose more impact height though. So you impart more topspin.

What are your thoughts on the ideal angle between racket shaft and forearm at impact? For a flat serve, I would have thought you need more racket head speed. But it would seem not... as the angle is small for a flat serve, close to zero... So for spin serves the racket head moves faster than for flat serves, but much of speed goes into creating rotation and not only forward speed?



Thanks

[johnyandell]

I think the racket head speeds are about the same--like you saw in Stanley's book it's the path that is different. The contact for both first and second serves should be with the ball inside or to the left of the hand when viewed from the rear. How far determines (among other factors) the speed/spin balance.

The angle is not set in stone. 15-30 degrees very roughly for the first serve. 30 to 40 degrees for the second. That's what I see when I look at Fed or Sampras from the rear views.

[tennis_chiro]

Interactive Forum directiry

I just realized the Interactive Forum videos are not in the Stroke Archives or High Speed Archives. Have you considered an additional left column directory heading for those videos? It would be nice to be able to find those. Dimitrov, Sock and Muguruza have nothing in the archives, but you had some good clips on them in Interactive Forums. I'm pretty sure there are many more. Even though you don't have the full archive ready, it would be nice to be able to find those a little easier

don

[johnyandell]

Don,
Here is the list:

http://www.tennisplayer.net/members/forum/past_forum.html

You can also find it by clicking on "see all articles" by category link on the front page and then click on Forum.