30 Jan 2005 17:39:55
go raptors!
simple serve question???

i've tried alot of stuff on my serve and being here in canadian winter
haven't had that much practice.

but simple question,

on generally flat serve and then second (spin) serve, what would be
the general angle the racquet vs. the ground???............... i see
people saying if it faces down at all, the ball will go straight down,
but seems to me it could face down pretty well if you are getting
topspin...................... looking at roddick/safin etc, it seems
their racquet is facing down probably 20 degrees, but they put big
top-spin on it..... obviously, topspin and flat are two different
answers but curious in general.

very curious about it and can't see racquet facing up at all, or then
no topspin whatsoever.

thanks in advance.


01 Feb 2005 12:55:32
Lloyd
Re: simple serve question???


"go raptors!" <smchant22@yahoo.com > wrote in message

> on generally flat serve and then second (spin) serve, what would be
> the general angle the racquet vs. the ground???

Racquet-face should be vertical but to be honest, you don't think about
these things when you're serving. You try out a lot of things and then stick
with what works....
............... i see
> people saying if it faces down at all, the ball will go straight down,
> but seems to me it could face down pretty well if you are getting
> topspin...................... looking at roddick/safin etc, it seems
> their racquet is facing down probably 20 degrees, but they put big
> top-spin on it..... obviously, topspin and flat are two different
> answers but curious in general.

On the kick (topspin) serve the racquet comes over the ball from low to up;
it certainly doesn't hit the top of the ball.




31 Jan 2005 23:36:21
Top Spin
Re: simple serve question???

On 30 Jan 2005 17:39:55 -0800, smchant22@yahoo.com (go raptors!)
wrote:

>i've tried alot of stuff on my serve and being here in canadian winter
>haven't had that much practice.
>
>but simple question,
>
>on generally flat serve and then second (spin) serve, what would be
>the general angle the racquet vs. the ground???............... i see
>people saying if it faces down at all, the ball will go straight down,
>but seems to me it could face down pretty well if you are getting
>topspin...................... looking at roddick/safin etc, it seems
>their racquet is facing down probably 20 degrees, but they put big
>top-spin on it..... obviously, topspin and flat are two different
>answers but curious in general.
>
>very curious about it and can't see racquet facing up at all, or then
>no topspin whatsoever.
>
>thanks in advance.

Many, many years ago, I attended one of Vic Braden's Tennis Colleges.
Among the many very valuable things I learned is that there are only
four things that affect the flight of the ball:

1. The instantaneous trajectory of the ball at the moment of impact
with the racket strings. For the serve, this should be close to zero
and so not a factor.

2. The orientation of the racket face. This completely determines the
initial trajectory. For the serve where the ball is instantaneously
stationary, the ball will have an initial trajectory that is
perpenticular (in 2 dimensions) to the racket face. This is assuming
that the ball strikes the center of the racket. So it the racket face
is perfectly vertical, the ball will initially be travelling
horizontally. Nothing else has a significant effect on initial
trajectory.

3. The component of racket velocity parallel to the initial ball
trajectory. This is the sole determiner of initial velocity. If the
racket face in traveling 200 kph in the direction of the initial
trajectory, then the ball will have about that initial velocity.

4. The component of racket speed perpendicular to the initial
trajectory (both X and Y). This is the sole determiner of initial
spin. It has negligible effect on either initial; velocity or
trajectory.

Note that if you want the ball to start out at 200 kph and you intend
to strike it at a 45 degree angle to impart spin, the actual racket
speed will need to be 1.4 * 200 = 283 kph. That's why flat serves are
the fastest -- all of the racket speed is transferred to the ball.

Note also that spin has negligible effect on the initial trajectory.
Players who hit with heavy topspin do NOT lift the ball. They actually
cause the ball to drop faster.

A cool experiment would be to set up a belt, like on a wide belt
sander that could be run in either direction. Then fire tennis balls
at the center of the belt with the belt (a) stopped, (b) moving
vertically up, and (c) moving vertically down. A high speed camera
will show that the initial trajectory of the ball off of the belt will
be almost the same regardless of the speed or direction of the belt.

The belt speed will affect the trajectory later on because of the spin
imparted to the ball.

All that only determines the initial trajectory. Now gravity and air
resistance take over. Ignoring air resistance, the ball will follow a
parabolic curve toward the ground. The vertical velocity will increase
by the acceleration of gravity (g). Add wind resistance and total
velocity will slow by a complicated formula that is probably a
function of a variable power (between 2 and 3) of the velocity.

The bottom line: pay attention to the orientation of the racket face
first and foremost. Everything else is secondary. Once you understand
that, you can start adding spin.

--
Email: Usenet-20031220 at spamex.com
(11/09/04)


02 Feb 2005 12:48:31
Lloyd
Re: simple serve question???


"Top Spin" <ToppSpin@hotmail.com > wrote in message

> The bottom line: pay attention to the orientation of the racket face
> first and foremost. Everything else is secondary. Once you understand
> that, you can start adding spin.

This is from the standpoint of the scientist. Any actual player thinking
first and foremost about racket-face orientation is bound to screw up
badly........

Try it. Go out on court and concentrate exclusively on the angle of your
racket-face and report back on how you're doing.




01 Feb 2005 22:40:51
Top Spin
Re: simple serve question???

On Wed, 2 Feb 2005 12:48:31 +0800, "Lloyd" <watiyinna@"remove this to
reply" smartchat.net.au > wrote:

>
>"Top Spin" <ToppSpin@hotmail.com> wrote in message
>
>> The bottom line: pay attention to the orientation of the racket face
>> first and foremost. Everything else is secondary. Once you understand
>> that, you can start adding spin.
>
>This is from the standpoint of the scientist. Any actual player thinking
>first and foremost about racket-face orientation is bound to screw up
>badly........
>
>Try it. Go out on court and concentrate exclusively on the angle of your
>racket-face and report back on how you're doing.

I've been doing just that for 20+ years. For the prior 30, I played
under some wrong notions that I was taught as a kid by tennis coaches.
Since the Braden school, my game has improved from about 3.0-3.5 to a
solid 4.5 when I was played regularly.

Clearly, you cannot consciously think about racket orientation while
playing, but knowing the basic physics will enable you to practice
strokes that have some hope of working when you do practce and convert
that conscious knowledge into muscle memory.

You try it.


--
Email: Usenet-20031220 at spamex.com
(11/09/04)


02 Feb 2005 11:30:08
Wen Shang
Re: simple serve question???


"Top Spin" <ToppSpin@hotmail.com > wrote in message
news:k9t001pftsimmdj70keg7ttlrsmltbft6b@4ax.com...
> On Wed, 2 Feb 2005 12:48:31 +0800, "Lloyd" <watiyinna@"remove this to
> reply" smartchat.net.au> wrote:
>
> >
> >"Top Spin" <ToppSpin@hotmail.com> wrote in message
> >
> >> The bottom line: pay attention to the orientation of the racket face
> >> first and foremost. Everything else is secondary. Once you understand
> >> that, you can start adding spin.
> >
> >This is from the standpoint of the scientist. Any actual player thinking
> >first and foremost about racket-face orientation is bound to screw up
> >badly........
> >
> >Try it. Go out on court and concentrate exclusively on the angle of your
> >racket-face and report back on how you're doing.
>
> I've been doing just that for 20+ years. For the prior 30, I played
> under some wrong notions that I was taught as a kid by tennis coaches.
> Since the Braden school, my game has improved from about 3.0-3.5 to a
> solid 4.5 when I was played regularly.
>
> Clearly, you cannot consciously think about racket orientation while
> playing, but knowing the basic physics will enable you to practice
> strokes that have some hope of working when you do practce and convert
> that conscious knowledge into muscle memory.
>
> You try it.
>
>
> --
> Email: Usenet-20031220 at spamex.com
> (11/09/04)

Both of you are RIGHT! But you are talking about different stages of
developing your serves.

WS