Howard Brody - The Physics and Technology Of Tennis & Swing Speed Vs. Racquet Mass
Shakes
http://www.amazon.com/dp/0972275908?tag=thetennisserver&link_code=as3&creativeASIN=0972275908&creative=373489&camp=211189
).
It's a really good book with a lot of exhaustive figures, stats, specs
et al about how strings, string tensions, swingweights, court surfaces
etc. affect the speed/bounce etc.
There is a lot of data and results that explain how much topspin is
too much, about how court surfaces affect the bounce and speed (like,
for example Deco II vs. Rebound Ace vs. grass vs. clay), the various
kinds of tennis balls, racquet frames, head-light, head-heavy, and
even balanced racquets etc.
Worth a read.
However, Brody admits not being able to do more study on what I
consider the most important study - Which is more important to impart
power/momentum to the ball - swing speed or racquet mass ?
He says:
QUOTE:
"So if we could measure the racquet head speed as a function of either
the swing weight or the mass of the racquet then we could figure out
whether a heavier racquet or a lighter racquet was optimum for a
player as far as ball speed was concerned. There has been an attempt
to do this with about 8 people; but that's not enough and that amount
of data isn't good enough. So what's needed is a study with hundreds
of people. That's a major area that needs investigation."
To me, this is a critical study because this is the fundamental
difference between how pro's used to hit the ball in the '90's, and
how they hit the ball now.
It's clear that pros today use lighter racquets that they swing harder
and faster, using open stance and SW/W grips. But does that impart
more weight/power to the shot than when you take a long, fast, full
cut at the ball with a significantly heavier racquet, using a more
traditional grip ?
Pelle Svanslös
> I was just reading Prof. Brody's excellent book (
> http://www.amazon.com/dp/0972275908?tag=thetennisserver&link_code=as3&creativeASIN=0972275908&creative=373489&camp=211189
> ).
>
> It's a really good book with a lot of exhaustive figures, stats, specs
> et al about how strings, string tensions, swingweights, court surfaces
> etc. affect the speed/bounce etc.
>
> There is a lot of data and results that explain how much topspin is
> too much, about how court surfaces affect the bounce and speed (like,
> for example Deco II vs. Rebound Ace vs. grass vs. clay), the various
> kinds of tennis balls, racquet frames, head-light, head-heavy, and
> even balanced racquets etc.
>
> Worth a read.
>
> However, Brody admits not being able to do more study on what I
> consider the most important study - Which is more important to impart
> power/momentum to the ball - swing speed or racquet mass ?
If you forget about the swing speed as a function of swing weight, and
only consider masses, speeds and collisions, the answer is swing speed.
> "So if we could measure the racquet head speed as a function of either
> the swing weight or the mass of the racquet then we could figure out
> whether a heavier racquet or a lighter racquet was optimum for a
> player as far as ball speed was concerned. There has been an attempt
> to do this with about 8 people; but that's not enough and that amount
> of data isn't good enough. So what's needed is a study with hundreds
> of people. That's a major area that needs investigation."
Hard to say what Brody is referring to with the 8 people study, whether
or not it's the basis for Cross in the following.
This is a scan from "Technical Tennis" by Cross & Lindsey. It's mostly
about rebound power (the same as ACOR in your book) but when discussing
whether rebound power is a good definition of racquet power, they touch
the above.
"It would seem that if you want to maximize power, all you would have to
do is choose the racquet with the greatest rebound power at the location
where you typically hit the ball for a certain kind of shot.
This is indeed true, but before we can make rebound power our official
definition of power, we first must slay a persistent objection to using
this power comparison criteria. That objection states that if the
easiest and most effective way to increase the rebound power of a
racquet is to increase the weight (or more correctly, the swingweight,
as we will see later), then the gain in rebound power will be more than
lost due to a decrease in racquet speed, and the exit speed will
actually end up being less. The answer to this objection is twofold:
first, the result of the tradeoff between more rebound power and less
racquet speed depends on the stroke, and second, the objection is
incorrect to begin with. Let's address each of these.
First, even assuming racquet speed does decline with increased weight,
the consequence of this depends on whether the ball is going faster than
the racquet or not. The faster the ball speed compared to the racquet
speed, the more the contribution of rebound speed compared to racquet
speed. So for volleys and slow swings, a heavier racquet with a higher
rebound power at the impact point will likely add to exit speed, even if
the racquet speed is less. For very fast swings and serves, any slowing
of the racquet due to extra weight will likely decrease the final ball
speed. Table 1.1 shows these relationships.
In general, the slower you swing compared to the incoming ball, the
proportionately more important is rebound power (and hence weight) to
your exit speed. Or, in other words, the slower your swing, the
more important to you is your racquet in the outcome of your shots. The
faster you swing, the proportionately more important is the racquet
speed. Or, in other words, the faster you swing, your racquet is less
important to the speed of your shots. It is also true for any given
player that he or she would probably do better with a heavier racquet
for volleys (ignoring maneuverability), a moderate weight racquet for
groundstrokes, and a lighter racquet for serves. Unfortunately you
can't change your racquet between shots.
The second part of the answer to the objection is the more important�the
racquet does not slow down enough to cancel gains in rebound power and
cause exit speed to decline. This is true for three reasons: (1) except
for a first serve, the player can almost always swing faster if he wants
to, (2) it has been experimentally shown that the actual decline in
racquet speed with a heavier racquet is quite small, and (3) the
increase in rebound speed and decline in racquet speed virtually
cancel each other. As a result, for any given effort, there is little or
no decline in exit speed for an increase in weight within the range of
racquet weights on the market. And if there is, the player can swing
with slightly greater effort anyway. The reason is that the main
constraint in swinging faster is the weight (swingweight) of the arm,
not of the racquet. The difference in (swingweight) weights between any
two racquets is relatively very small compared to the weight of the arm
and thus has very little influence on racquet speed. In fact,
experiments have shown that the racquet speed varies as
1/(swingweight)^0.27 for maximum effort swings. Consequently, if the
swingweight of a racquet is doubled (e.g., from 300 to 600 grams) then
the maximum swing speed decreases by only about 17 percent. A similar
effect occurs when throwing balls of different weight. If you can throw
a 57-gram tennis ball at 60 mph, then you can throw a 145-gram baseball
at about 55 mph, even though it is 2.5 times heavier than a tennis ball.
Your throw speed is limited mainly by the weight of your arm, which is a
lot heavier than a tennis ball or a baseball and therefore has a much
larger swingweight. (See Match Point Box 1.2 for more discussion on the
influence of weight on swing speed.)
We are now able to state what is meant by racquet power when you are
comparing one racquet to another.
RACQUET POWER DEFINED AS REBOUND POWER
Because, for most any given racquet, you can change your swing speed for
any given shot situation, and because you must change your swing speed
in different situations (i.e., serve, volley, groundstroke, etc.),
and because the actual effect on swing speed of a change in weight is
small, we will consider the properties of the racquet that increase the
rebound power as being most important in the racquet's contribution to
power in actual game situations. Except in an all-out first serve, those
properties that make the racquet easier or harder to swing tend to be
ignored or overridden by the player, and thus are not properties that
dictate certain power results without exception, as rebound power does.
The major benefit of using rebound power as the prime indicator of power
is that it is independent of effort, swing speed, and stroke situation.
It is independent of the ability, style, technique, and temperament
of the player. So, however fast you choose to swing your racquet, and
whatever effort it may take, the racquet with the greatest rebound power
will usually hit the ball fastest (except for a maximum effort serve, as
explained in Match Point Box 1.2). If you want to hit the ball even
faster, then simply swing faster, because there is nothing stopping you
from doing so, except the need to get the ball in the court. Rating
racquet power by rebound power is not perfect, but it is the most
practical and useful measurement considering the way most players
actually use and interact with their racquets. We are leaving swing
speed up to the player and considering the racquet mainly as a rebound
platform. Because most of the time the player has a "swing speed
override" option at his or her disposal, we will consider the racquet's
contribution to power in terms of its rebound power.
Rebound power is the "power" that is available due simply to the
racquet's existence and that is always available on every swing, shot,
and situation that the game of tennis can throw at you."
--
"Listen first! Hiss later!"
Shakes
> Shakes wrote:
> > I was just reading Prof. Brody's excellent book (
> > ).
>
> > It's a really good book with a lot of exhaustive figures, stats, specs
> > et al about how strings, string tensions, swingweights, court surfaces
> > etc. affect the speed/bounce etc.
>
> > There is a lot of data and results that explain how much topspin is
> > too much, about how court surfaces affect the bounce and speed (like,
> > for example Deco II vs. Rebound Ace vs. grass vs. clay), the various
> > kinds of tennis balls, racquet frames, head-light, head-heavy, and
> > even balanced racquets etc.
>
> > Worth a read.
>
> > However, Brody admits not being able to do more study on what I
> > consider the most important study - Which is more important to impart
> > power/momentum to the ball - swing speed or racquet mass ?
>
> If you forget about the swing speed as a function of swing weight, and
> only consider masses, speeds and collisions, the answer is swing speed.
>
But I think there is a place where the gain in racquet mass
compensates for the slight loss in swing speed. Don't you agree ? At
least, going by the quote you put up from "Technical Tennis", I think
that is so.
This is very true. The golden rule seems to be to add as much lead
tape as possible to the racquet head without sacrificing swing speed.
For Sampras, it turned out to be a total added weight of almost 30-33
gms. I think his stock St. Vincent Pro Staff 85 weighs about 360 gms.
His racquet weighed in at 393 gms ( I remember reading more than
once). Lendl's racquet weighed in close to 400 gms.
Thanks. That almost answers my question definitely that it is the
racquet mass that is more important than swing speed.
You are one of the more knowledgeable posters. You give very good
points. You should have posted more in the discussions we had - esp.
about players from the past (Sampras, Becker etc.) not cut out for
this era etc. :-) Also, I wish you were a Fed fan.
I had one more question that is a direct offshoot of the swing speed
vs. racquet mass.
Which type of shot do you think gets through to the opponent faster ?
The SW/W topspin FH of most players today, say, Nadal, for example or
the Eastern/more traditional FH of, say, Sampras, Lendl ?
I am curious because the SW/W FHs prevalent today are at higher swing
speeds - more wrist, open stance, more angular velocity. But the FHs
of Sampras, Lendl, Korda etc. were at a slightly lower swing speeds,
but with a significantly higher racquet mass (30-40 gms more), and
with a long, full swing based on timing.
Vari L. Cinicke
Depends on what you are trying to do with the ball.
If you are trying to volley or hit an approach shot, the heavier racket
is going to be better.
For passing shots, the racket head speed and severe top spin are the
ticket. The 2 shot passing shot has become almost routine now. Hit a
safe, hard hit non-passing but rapidly dipping shot and follow it up
with an easy passing shot.
> You are one of the more knowledgeable posters. You give very good
> points. You should have posted more in the discussions we had - esp.
> about players from the past (Sampras, Becker etc.) not cut out for
> this era etc. :-) Also, I wish you were a Fed fan.
>
> I had one more question that is a direct offshoot of the swing speed
> vs. racquet mass.
>
> Which type of shot do you think gets through to the opponent faster ?
> The SW/W topspin FH of most players today, say, Nadal, for example or
> the Eastern/more traditional FH of, say, Sampras, Lendl ?
>
Which shot do you think can land closer to the lines with more reliability?
If you were facing Nadal and approaching the net, would you prefer that
he hits with his current grip or would you request him to hit with an
Eastern grip?
> I am curious because the SW/W FHs prevalent today are at higher swing
> speeds - more wrist, open stance, more angular velocity. But the FHs
> of Sampras, Lendl, Korda etc. were at a slightly lower swing speeds,
> but with a significantly higher racquet mass (30-40 gms more), and
> with a long, full swing based on timing.
Sampras had a monster forehand. But his forehand, especially the running
one, was as liable to hit inside the court as hit 15 feet out. Watch
Nadal's running forehand if you want to see what the ball can be made to
do with the extreme grips and swings. His favorite hook shot would be
impossible without the extreme top spin. The top spin shot also takes
the opponent more out of position on a more regular basis than the
flatter shots could.
--
Cheers,
vc
Shakes
> On 2/12/2011 3:58 PM, Shakes wrote:
>
>
> > Thanks. That almost answers my question definitely that it is the
> > racquet mass that is more important than swing speed.
>
> Depends on what you are trying to do with the ball.
>
> If you are trying to volley or hit an approach shot, the heavier racket
> is going to be better.
>
> For passing shots, the racket head speed and severe top spin are the
> ticket. The 2 shot passing shot has become almost routine now. Hit a
> safe, hard hit non-passing but rapidly dipping shot and follow it up
> with an easy passing shot.
>
Agreed. Lendl seemed an exception though. He tried to pass mostly with
his flat groundies. Actually, tried to overpower with the pass is a
better way to describe him.
As an aside, that's why I insist that part of the reason why it has
become easier to pass the players is because the approach shot is hit
using the same way as a passing shot - rather than relying on a flat,
penetrating shot - it is hit with more topspin than advisable. Esp.
the inside-out FH.
>
> > I had one more question that is a direct offshoot of the swing speed
> > vs. racquet mass.
>
> > Which type of shot do you think gets through to the opponent faster ?
> > The SW/W topspin FH of most players today, say, Nadal, for example or
> > the Eastern/more traditional FH of, say, Sampras, Lendl ?
>
> Which shot do you think can land closer to the lines with more reliability?
The topspin FH is definitely more reliable. But the book which I am
reading has an interesting figure which shows that for a topspin shot
to land with the same depth as a flat shot, it has to be hit higher.
So, inspite of the increased swing speed and angular velocity, it is
still not the fastest path to the opponent.
>
> If you were facing Nadal and approaching the net, would you prefer that
> he hits with his current grip or would you request him to hit with an
> Eastern grip?
>
Both have it's advantages/disadvantages. If closing in fast to the net
is more important for you as a net rusher (in which case it means you
are more comfortable handling angles than pure pace), SW/W grip would
be preferable.
But if, as a net rusher, you are more comfortable handling pure pace
at the net, you would prefer Nadal to use an Eastern grip.
> > I am curious because the SW/W FHs prevalent today are at higher swing
> > speeds - more wrist, open stance, more angular velocity. But the FHs
> > of Sampras, Lendl, Korda etc. were at a slightly lower swing speeds,
> > but with a significantly higher racquet mass (30-40 gms more), and
> > with a long, full swing based on timing.
>
> Sampras had a monster forehand. But his forehand, especially the running
> one, was as liable to hit inside the court as hit 15 feet out. Watch
> Nadal's running forehand if you want to see what the ball can be made to
> do with the extreme grips and swings. His favorite hook shot would be
> impossible without the extreme top spin. The top spin shot also takes
> the opponent more out of position on a more regular basis than the
> flatter shots could.
>
> --
> Cheers,
>
> vc
Yes, no doubt that the top spin shot takes the opponent more out of
position. But from what I've read in the book, it also gives more time.
Manco
> ticket. The 2 shot passing shot has become almost routine now. Hit a
> safe, hard hit non-passing but rapidly dipping shot and follow it up
> with an easy passing shot.
>
This is a tactic that Nadal pioneered. I never saw it being done
before him. Now everyone does it. He's a true innovator of the game,
unlike Freddy who bashes mindlessly.
Vari L. Cinicke
> On Feb 12, 1:37 pm, "Vari L. Cinicke"<variesn...@gmail.com> wrote:
>> On 2/12/2011 3:58 PM, Shakes wrote:
>>
>
>>
>>> Thanks. That almost answers my question definitely that it is the
>>> racquet mass that is more important than swing speed.
>>
>> Depends on what you are trying to do with the ball.
>>
>> If you are trying to volley or hit an approach shot, the heavier racket
>> is going to be better.
>>
>> For passing shots, the racket head speed and severe top spin are the
>> ticket. The 2 shot passing shot has become almost routine now. Hit a
>> safe, hard hit non-passing but rapidly dipping shot and follow it up
>> with an easy passing shot.
>>
>
> Agreed. Lendl seemed an exception though. He tried to pass mostly with
> his flat groundies. Actually, tried to overpower with the pass is a
> better way to describe him.
>
> As an aside, that's why I insist that part of the reason why it has
> become easier to pass the players is because the approach shot is hit
> using the same way as a passing shot - rather than relying on a flat,
> penetrating shot - it is hit with more topspin than advisable. Esp.
> the inside-out FH.
>
I agree with that. The approach shot shouldn't be left hanging.
But I seem to recall reading that passing shots are measurably more
accurate these days. Vic Braden?
I think it is a combination of many factors. The 2 prime factors in my
opinion are 1) the reduced speed and increased reliability of bounce of
the courts and 2) the court coverage and accurate and heavy top spin
passing shots.
>>
>>> I had one more question that is a direct offshoot of the swing speed
>>> vs. racquet mass.
>>
>>> Which type of shot do you think gets through to the opponent faster ?
>>> The SW/W topspin FH of most players today, say, Nadal, for example or
>>> the Eastern/more traditional FH of, say, Sampras, Lendl ?
>>
>> Which shot do you think can land closer to the lines with more reliability?
>
> The topspin FH is definitely more reliable. But the book which I am
> reading has an interesting figure which shows that for a topspin shot
> to land with the same depth as a flat shot, it has to be hit higher.
> So, inspite of the increased swing speed and angular velocity, it is
> still not the fastest path to the opponent.
>
>>
>> If you were facing Nadal and approaching the net, would you prefer that
>> he hits with his current grip or would you request him to hit with an
>> Eastern grip?
>>
>
>
> Both have it's advantages/disadvantages. If closing in fast to the net
> is more important for you as a net rusher (in which case it means you
> are more comfortable handling angles than pure pace), SW/W grip would
> be preferable.
>
> But if, as a net rusher, you are more comfortable handling pure pace
> at the net, you would prefer Nadal to use an Eastern grip.
>
When facing someone who hits with a lot of topspin and pace, you have a
lot more ground to cover at the net. Remember that the heavy top spin
usually implies an excellent top spin lob. You close in too much to the
net at your peril. You hang too far back at your peril too.
All I know is that even Karlovic with his serve and reach doesn't dare
S/V on his 2nd serves except on the fastest surfaces.
>>> I am curious because the SW/W FHs prevalent today are at higher swing
>>> speeds - more wrist, open stance, more angular velocity. But the FHs
>>> of Sampras, Lendl, Korda etc. were at a slightly lower swing speeds,
>>> but with a significantly higher racquet mass (30-40 gms more), and
>>> with a long, full swing based on timing.
>>
>> Sampras had a monster forehand. But his forehand, especially the running
>> one, was as liable to hit inside the court as hit 15 feet out. Watch
>> Nadal's running forehand if you want to see what the ball can be made to
>> do with the extreme grips and swings. His favorite hook shot would be
>> impossible without the extreme top spin. The top spin shot also takes
>> the opponent more out of position on a more regular basis than the
>> flatter shots could.
>>
>
> Yes, no doubt that the top spin shot takes the opponent more out of
> position. But from what I've read in the book, it also gives more time.
It might give you more time to cover the first shot. Unless you hit a
great defensive shot back, by the 3rd shot of the series, you can't
cover both the open court and the shot hit behind you. And the extra
time the top spin shot allows your opponent to wait means that you will
have to choose between leaving the open court shot uncovered or the shot
behind you uncovered.
--
Cheers,
vc
Vari L. Cinicke
I think Manco of yesterday preemptively countered that really well. Sorry!
--
Cheers,
vc