Have a Question for Me?

[airforce1]

John, I hear a tennis pro friend of mine say the reason why Fed hits so big on the forehand is because he's moving into the forehand (towards the net) when he hits it. However, it also appears that he hits some huge inside-out forehands moving literally sideways along the baseline towards the alley. He is certainly not moving "foreward" towards the net in these cases, yet still hits huge. What is creating the huge shot in those cases? Is it the rotational force? Any thoughts?

It's just so close to a full on slap shot that stepping would just create too much power to control.

[oliensis]

In the optimal scenario like in this archived stroke, Federer does manage to get his weight moving into the shot:

http://www.tennisplayer.net/members/strokearchive/pro_men/rogerfederer/rogerfederer_forehand/rogerfederer_fh_inside_out/rogerfederer_fh_inside_out.html?FedererFHInsideOutFront3.mov

However, when the incoming shot is more forcing, then he doesn't always manage to get his weight moving forward. But what he does do is manage to convert angular momentum (from the unit turn and the take-back of the racket) into linear momentum, and transfers it to the ball via the speed of the racket head. Like in this one: http://www.tennisplayer.net/members/...eOutFront2.mov

I think the former is preferable when possible, but it's not always possible. The ability to play offensively from a sub-optimal position is partially a function of being able to hit out when optimal weight transfer is not possible...but when only angular momentum is converted to linear momentum.

[airforce1]

is it accepted in tennis to use the term angular momentum anytime there is curve in the racket path?

My understanding of the science definition of angular Mo is that it must be working in a circle as from a radius sweeping extended from a fixed center (like a tire swing). Also that otherwise, the momentum would be a form of linear momentum, even though the path may not be straight.

My point here is that if my understanding of these terms is near correct, then we never have true angular momentum in a swing of the stick. It would all be a form of linear momentum, although on some type of curved path. So at what point in "tennis terms" do we decide to refer to it as angular momentum?

Maybe Julian can help with the definitions from each perspective, given his tennis and scientific backgrounds?

[johnyandell]

Not my area of knowledge! I could make something up but it would be just something I made up.

[airforce1]

Your frankness is always refreshing. Guess this should have been in another thread, but thought this could be something I missed at the last world conference or something. LoL.

[oliensis]

From dictionary.com:
angular momentum 

–noun Physics. the product of the moment of inertia of a body about an axis and its angular velocity with respect to the same axis.

Also called moment of momentum.


--------------------------------------------------------------------------------

Origin:
1865–70

My point was that there's power generated from torque and there's power generated from weight transfer forward into the line of the oncoming ball. And the former is more like pure angular momentum than it is like forward weight transfer. (E.g. Jack Kramer's forehand has more forward weight transfer and the 2nd Federer link in the post above has more torque (angular momentum) operating.) While there's rarely anything perfect in the real world, there are methods of abstracting these 2 different ideas in a tennis stroke and analyzing how power can be generated even when falling away from the line of he oncoming ball.

[julian]

Momentum

is it accepted in tennis to use the term angular momentum anytime there is curve in the racket path?

My understanding of the science definition of angular Mo is that it must be working in a circle as from a radius sweeping extended from a fixed center (like a tire swing). Also that otherwise, the momentum would be a form of linear momentum, even though the path may not be straight.

My point here is that if my understanding of these terms is near correct, then we never have true angular momentum in a swing of the stick. It would all be a form of linear momentum, although on some type of curved path. So at what point in "tennis terms" do we decide to refer to it as angular momentum?

Maybe Julian can help with the definitions from each perspective, given his tennis and scientific backgrounds?

Generally speaking we apply a notion of angular momentum in tennis
to a body of a player PLUS a racket,
NOT to a racket itself.

If we agree on this one :
for open stance an angular momentum is MORE important
for neutral stance a linear momentum is MORE important

[airforce1]

I thank each of you for your comments on this, but seems to me that our definitions of angular Mo and linear Mo are very loose, which seems fine for discussing tennis swings, till we get down to talking about this or that swing having more of something. When we get to measurements I expect we will find that we will measure a different aspect or term, rendering our discussions moot or needing to transpose words to make sense of them.
Does that make sense?
I'm working on it if anyone cares, and will get back with what I can find. Mentioning here is part of my search for info.

[uspta146749877]

Angular momentum and Scotch

I thank each of you for your comments on this, but seems to me that our definitions of angular Mo and linear Mo are very loose, which seems fine for discussing tennis swings, till we get down to talking about this or that swing having more of something. When we get to measurements I expect we will find that we will measure a different aspect or term, rendering our discussions moot or needing to transpose words to make sense of them.
Does that make sense?
I'm working on it if anyone cares, and will get back with what I can find. Mentioning here is part of my search for info.

Please go to

http://www.tennisplayer.net/bulletin/showthread.php?t=2&page=29

and read posts by emeralda and me.
I have to look for some Scotch.
Maybe some posts by julian as well

[normand_trempe]

ever seen a FH slicer ?

Hello John! I wanted to tell you that i love the site in general, it's incredible. I really like the oldies videos and the famous coaches section. Also the Bill tilden excerpts are excellent. If i would had something would be some clips of Olivier Rochus, Michael Chang, Arnaud Clément. There are not enough references for small players like me, to see what his possible for small players on the pro tour and what secrets they have to be able to compete against giants. They'r movement has to be different, they'r mental attitude also and they'r tactics. Now my question for you. Have you ever seen a player who has a one handed slice he uses regurlarly to upset the rythm of another player ? And do you think it could be useful at the pro level ? Thanks a lot.
Also, i was just curious if you taught tennis for a living or if you do this website full time or what exactly you do :-) ? Tovarich

[johnyandell]

Thanks for the comments. Doubt though you'd see any categorical technical differences in the players you mention.

We know that slice thing can work at most levels. You see a crazy person like Santoro use it in the pros (two handed usually), but if it was really effective I think you would see more players use it. The one possible question I have is what if Roger hit that hard low cc slice to nadal's forehand more?

Tennisplayer is (more than) full time...but I also work with Advanced Tennis, the foundation that does the high speed filming. I do some technical consulting for players. Spend way too much time on it, but also coach girls' high school tennis in San Francisco--lot of fun and free entertainment. In fact I'll be putting up our team video in December--captures I think the fun we should all have with tennis.

[10splayer]

Dear John,

First of all, love the site, and recommend it to all my students. Just wondering if Kerry Mitchell is still writing for you, haven't seen any of his work of late. I always thought his "true alignment" and "what is open stance" articles were priceless.

Thanks,

Chico9166

[johnyandell]

Yeah those were great articles!

Kerry taught and coached with me for 15 years in San Francisco. He and his partner moved to Canada (and Mexico--what a life style) a couple of years ago and that has slowed things down.

I'll tell him though that there are requests for more....

[10splayer]

Yeah those were great articles!

Kerry taught and coached with me for 15 years in San Francisco. He and his partner moved to Canada (and Mexico--what a life style) a couple of years ago and that has slowed things down.

I'll tell him though that there are requests for more....

Thanks for your time, best of wishes in this holiday season.

[normand_trempe]

Thanks! and another question!

Thanks for the comments. Doubt though you'd see any categorical technical differences in the players you mention.

We know that slice thing can work at most levels. You see a crazy person like Santoro use it in the pros (two handed usually), but if it was really effective I think you would see more players use it. The one possible question I have is what if Roger hit that hard low cc slice to nadal's forehand more?

Tennisplayer is (more than) full time...but I also work with Advanced Tennis, the foundation that does the high speed filming. I do some technical consulting for players. Spend way too much time on it, but also coach girls' high school tennis in San Francisco--lot of fun and free entertainment. In fact I'll be putting up our team video in December--captures I think the fun we should all have with tennis.

Thanks for your time. I agree that Fed should hit it there more, even come up to the net behind thos short ones when nadal is way far behind. I've been interested in the fh slice and will try to study it more, since there really isn't a technical prototype to teach it. The way the body is made, i think it has to be really different from the one h bh slice technique.
I thought It'd be fun to teach if there is a new style of player like a modern Santoro coming up at the club hehe. I'll be interested in seeing your video of highschool coaching since i just started coaching a college team in my hometown.
On another note, i think it would be great as a teaching tool to have montages of pro players doing different patterns of play. I say that because i realise that the visual element is so important in the learning of strokes and a lot of recreational players, even good ones, don't watch any tennis on tv and so don't have a model to imitate. It can take so long to get a feeling through to them but i think if they would just watch an image they often could learn so much quicker. Have you ever made one yourself ?
Last question, do you have any full matches where the camera angle is behind a player about at court height ? I feel watching tennis from the high angles doesnt really relate the speed of the game at wich it is played, the athleticism of the players and height they hit the balls over the net. I would love to get my hands on matches like that to show to my students.

I would love to have your job with this website and all! Thanks!Tovarich