Causes for different topspin bounces on the forehand

FiReFTW

Legend
Just wondering if anyone ever thought about this or maybe has some theories or something.

But what are the differences that make a topspin groundstroke ball behave differently from different players?

For example a junior (player A) from my group sessions has a ton of spin in his strokes, but its completely different than for example another junior (player B) spin.

Player A really swings furiously upward and the ball has the highest arc, but its not that fast more loopy arc and not penetrating, then as the ball bounces it flies into you like the ball picks up alot of speed instantly due to the spin, but it doesnt bounce super high just very towards you.

Player B has medium arc so less than player A, and his ball jumps towards u but slightly less fast but the bounce is quite higher, so even tho the arc is not as high the ball bounces way higher but not as fast towards you more upward.

And then my shot apparently when talking to some from the group, according to them my shot has the lowest arc usually but is more penetrating and yet it bounces much higher than player A who has a very high arc.

So what are the differences between these different spins?

The most odd one is from player A as I dont get how come he has such a high arc and as the ball bounces it picks up like 5x speed into you (jusr appears so obviously it doesnt work like that) from alot of spin, but yet the bounce is not particulary high, its very odd and I dont know what to make of that.

So simplified:

Shot A

High arc over net
Medium bounce
Ball shoots towards you after bounce

Shot B

Medium arc over net
High bounce
Ball shots more up into you

Shot C

Lowest arc over net
High bounce
Ball shots more up into you
 
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Curious

Legend
Oh this one is easy! A combination of factors: rhs, racket face angle at contact, racket swingpath angle. Missed anything? No, that’s about it. Next please!:p
 

FiReFTW

Legend
Thats alot of things.

But anyway im still puzzled by A type, how can it be such a big arc like 3 net levels but bounce maybe a bit above waist height yet it jumps into you so it has to have a ton of spin but somehow it doesnt jump high.
 

FiReFTW

Legend
And yeah @Curious those things all affect the ball, but im more interested in what is different in these balls so they behave so different.
 

FiReFTW

Legend
Already said, some of those on my list make the difference. How would I know which one(s)?
Yes but some of those reasons might cause a different ball, im not looking what might cause it, im wondering what the difference is in those different balls to make such different effects.
 

Traffic

Hall of Fame
Probably 2 factors; spin, angle the ball hits the ground.
Player A's ball can be thought of as coming to the ground at near vertical angle, the spin wants to accelerate the ball toward the curtain.
Player B's ball is coming in at a shallower angle, the spin wants to accelerate the ball in similar manner as A, but because of the shallower angle, the ball doesn't bounce as high.
Player C's ball is coming in the shallowest angle, the slow spin actually decelerates the ball and has it deflect at smaller angle than either player A or B.

At least it sounds good...
 

FiReFTW

Legend
Probably 2 factors; spin, angle the ball hits the ground.
Player A's ball can be thought of as coming to the ground at near vertical angle, the spin wants to accelerate the ball toward the curtain.
Player B's ball is coming in at a shallower angle, the spin wants to accelerate the ball in similar manner as A, but because of the shallower angle, the ball doesn't bounce as high.
Player C's ball is coming in the shallowest angle, the slow spin actually decelerates the ball and has it deflect at smaller angle than either player A or B.

At least it sounds good...
Now im even more confused, are the player A B C in order with my shots A B C, because u said things that are not in line with it, like B bounce lower than A
 

Keendog

Semi-Pro
Are these players all the same height? That can affect bounce height.

This reminds me of playing around with the topspin dial on a ball machine. With speed high and spin only low it comes to you quick but post bounce slows down and bounces up. You can compensate for flat balls a bit by increasing the topspin. With the speed maxed out and the topspin dial maxed it will actually lift the ball higher over net, make it bounce much shorter, and give that heavy spin player A has.

So I would say it is a combination of ball speed and amount of topspin. A given player with a set amount of RHS might trade power for spin but with two different players, of different height as well, could conceivably hit a lot more spin with same amount of power as another player, ie no trade off. I think Player A hits hardest with most spin, the arc gives you the impression it is not hard, Player C hits second hardest with less spin, and Player B hits a similar amount of spin as Player C but with less power.

Remember if there is a larger arc, the ball is travelling further, so with the same ball speed it will take longer to get to you, but the speed is the still the same. On clay courts penetrating shots are less effective than heavy topspin so clay courters will prefer to hit like Player A, grass courters prefer pentrating shots as they skid through more than bounce up and will be clean winners ala Player C. Hard courters will balance the two out, perhaps like Player B

You would need a speed gun to test the theory out.
 

Keendog

Semi-Pro
Thats alot of things.

But anyway im still puzzled by A type, how can it be such a big arc like 3 net levels but bounce maybe a bit above waist height yet it jumps into you so it has to have a ton of spin but somehow it doesnt jump high.
I think there is a level of spin so high the ball doesn't lose speed post bounce as would normally happen, but will accelerate after bouncing. Especially on a grippy surface like a hard court
 

FiReFTW

Legend
@Keendog

Very cool post! Thats what I was looking for, very nice theory that we can discuss from.

Tho one thing worth mentioning is that player B and C also get alot of post bounce explosion from the spin, its not like it just bounces higher than player A, it also explodes just like A, but more higher like shoulder level, while A is more waist or a bit over level.

Btw height is similar but A is 3-4cm shorter (minor difference)
 

Traffic

Hall of Fame
Now im even more confused, are the player A B C in order with my shots A B C, because u said things that are not in line with it, like B bounce lower than A
Ah, sorry. A,B, C was supposed to correlate with your initial descriptions.
 

Fintft

Legend
Ever seen:

Shot D

Low arc over net
Low bounce
Ball skids even if it doesn't touch a line

That's what partners tell me my balls do (even on clay, but more so on hard courts).
 

FiReFTW

Legend
Ever seen:

Shot D

Low arc over net
Low bounce
Ball skids even if it doesn't touch a line

That's what partners tell me my balls do (even on clay, but more so on hard courts).
Yes usually shots from girl players do that, alot of penetration but little spin.
 

Fintft

Legend
Yes usually shots from girl players do that, alot of penetration but little spin.
Are you saying that I hit like a girl? :D

And here I was thinking that the skidding might have been due to full bed natural gut or the side spin, sigh.

Truth be told, both you and me have girl coaches (I got a second Romanian one in Europe now, besides the one in Canada)...
 

rogerroger917

Hall of Fame
Are you saying that I hit like a girl? :D

And here I was thinking that the skidding might have been due to full bed natural gut or the side spin, sigh.

Truth be told, both you and me have girl coaches (I got a second Romanian one in Europe now, besides the one in Canada)...
This is the dreaded WTA fh.
 

FiReFTW

Legend
Are you saying that I hit like a girl? :D

And here I was thinking that the skidding might have been due to full bed natural gut or the side spin, sigh.

Truth be told, both you and me have girl coaches (I got a second Romanian one in Europe now, besides the one in Canada)...
Well ATP men also sometimes hit extremely penetrating and lower spin, so not really, I just noticed that in general girls in majority seem to hit like this pretty much all the time more or less, very rare do you find a girl who has good amount of spin.

But men usually hit alot of spin but sometimes hit more flat, depending.
 

navigator

Hall of Fame
Unless you're an open-level player (or headed in that direction) - which hardly anyone here is - none of this spin business really matters much. Forget about the spin (and the velocity, for that matter) - it's a red herring - just try to put the ball in the right spot. The biggest obstacle to 98% of players here on TT - that is, the rec crowd - isn't a lack of topspin, insufficient pace, sub-standard technique, etc... it's a properly-installed net. Until that point is acknowledged, material improvement will remain elusive.
 

FiReFTW

Legend
Unless you're an open-level player (or headed in that direction) - which hardly anyone here is - none of this spin business really matters much. Forget about the spin (and the velocity, for that matter) - it's a red herring - just try to put the ball in the right spot. The biggest obstacle to 98% of players here on TT - that is, the rec crowd - isn't a lack of topspin, insufficient pace, sub-standard technique, etc... it's a properly-installed net. Until that point is acknowledged, material improvement will remain elusive.
Its more of a curiosity thing than anything else.
 

JohnYandell

Hall of Fame
Some facts. The ball loses about a third of its speed at the bounce due to the friction of the court--and slows down considerably more after. Most balls are half or less of initial velocity when they reach the opponent's racket. If that were not true it would be impossible to play tennis. The ball does not accelerate after the bounce although it can feel that way.
Second, we found in our study of Sampras's serve anyway that more topspin conserves an increment of speed. Third, the angle of the ball when it hits the court is a big factor in bounce height. If the arc is more downward prior to bounce the bounce is higher. But slower speed coming into bounce also affects height.
To answer the op's questions would take a shot spot to accurately break out all these factors.
 

Kevo

Legend
Unless you're an open-level player (or headed in that direction) - which hardly anyone here is - none of this spin business really matters much.
Anyone who plays 4.0 rec tennis or higher can certainly be helped by having a reasonable command of their topspin. Even at the 3.5 level you'll see players who are going to advance eventually that can vary spin and trajectory on their shots.

I think it's a really good idea for players to experiment with spins and clearance so they know what kind of choice they have for different scenarios. Once you get good at varying spin and trajectory it can open up all sorts of options. I use it all the time in doubles especially. Almost every shot I hit from the back court in doubles is a decision about how high to clear the net and how much spin versus pace I want.
 

Kevo

Legend
The ball does not accelerate after the bounce although it can feel that way.
I think that's a good way to put it. Our perceptions acclimate to what we see most often. This is why a knuckle ball is so effective in baseball. To hit the fastball you have to swing so quickly after the pitcher releases the ball, that a well timed knuckleball is almost impossible to hit because the batter has been conditioned to swing early.

If you always face a 50mph forehand with 1000rpm and then face a 50mph forehand with 3000rpm of spin you're going to feel like the ball is jumping at you even though the speed of the shot was the same.
 

sureshs

Bionic Poster
Oh this one is easy! A combination of factors: rhs, racket face angle at contact, racket swingpath angle. Missed anything? No, that’s about it. Next please!:p
The racket face angle is due to the last part of the racket swingpath angle for the same grip, so they are not independent. Rather, two of (grip, racket face angle, racket swingpath) are the two independent variables.
 

Kevo

Legend
The racket face angle is due to the last part of the racket swingpath angle, so they are not independent.
So if I swing my racquet in a straight line you're saying I can do that with only one face angle?

Is this the face angle? :unsure:
 

SystemicAnomaly

Talk Tennis Guru
Musings. Some factors to consider:

- initial launch angle/trajectory
- initial ball speed & spin
- spin/speed ratio
- ball type used (model, amt of felt, internal ball pressure, etc)
- atmospheric conditions (temp, altitude/barometric pressure, humidity, wind)
- court surface characteristics
- presence of other spin types (side spin, spiral spin)

Air drag on the ball is affected by atmospheric conditions. This will have an effect on trajectory and, ultimately, ball bounce behavior. Spiral spin will not have an effect on pre-bounce trajectory but can have a pronounced effect on bounce direction. Sidespin can have a pronounced effect on pre-bounce trajectory but has no effect on ball bounce direction.
.
 

FiReFTW

Legend
I don't think A exists.

Unless it's a ball made of lead, tennis ball doesn't go up X height and bounce off 1/4 or less of the X.
Just an ilustration.

Its exaggerated.

Its more like

A shot = 6-7 feet net clearance, bounce 4-5 feet
B shot = 5-6 feet net clearance, bounce 5-6feet
C shot = 4-5 feet net clearance, bounce 5-6feet high
 

FiReFTW

Legend
Some facts. The ball loses about a third of its speed at the bounce due to the friction of the court--and slows down considerably more after. Most balls are half or less of initial velocity when they reach the opponent's racket. If that were not true it would be impossible to play tennis. The ball does not accelerate after the bounce although it can feel that way.
Second, we found in our study of Sampras's serve anyway that more topspin conserves an increment of speed. Third, the angle of the ball when it hits the court is a big factor in bounce height. If the arc is more downward prior to bounce the bounce is higher. But slower speed coming into bounce also affects height.
To answer the op's questions would take a shot spot to accurately break out all these factors.
Really cool post.

Also @SystemicAnomaly also a great analysis

Anyway it was all hit on the same court, same balls... so all this is the same.

But like i said

Shots are like


A shot = 6-7 feet net clearance, bounce 4-5 feet
B shot = 5-6 feet net clearance, bounce 5-6feet
C shot = 4-5 feet net clearance, bounce 5-6feet

Also in terms of speed

A shot seems slowest and more loopy while B has more penetration and pace and C has the most pace

All shots jump into you but B and C jump high into you while A jumps more low into you.

I know its hard to guestimate but if you were guessing, what would you say are the differences between the 3?
 

user92626

Legend
Just an ilustration.

Its exaggerated.

Its more like

A shot = 6-7 feet net clearance, bounce 4-5 feet
B shot = 5-6 feet net clearance, bounce 5-6feet
C shot = 4-5 feet net clearance, bounce 5-6feet high
I see.

Well, those numbers are all possible, in the realm of reality.

The variation of thrust and topspin certainly can overwhelm the tennis ball mass enough to create such bounces.
 

FiReFTW

Legend
I see.

Well, those numbers are all possible, in the realm of reality.

The variation of thrust and topspin certainly can overwhelm the tennis ball mass enough to create such bounces.
Yes has to be some different combinations of pace, spin which also creates different angles how the ball hits the court.
 

FiReFTW

Legend
Heres a theory, is this possible?

Since shot A is the most odd of the 3

Shot A has much less pace and penetration its more loopy and slow

Could it be that shot A has alot of spin but not alot of pace, so the spin overwhelms the pace so much that upon bounce the ball forward spin grips the surface more and gets pushed more forward and lower.

Similar if you brushed the back of the ball completely up and add ton of spin but no forward pace, so ball would spin and go straight up then as it bounces the spin would make it shot forward.

Meanwhile shot B and C have more penetration and forward velocity and the spin then dips it down and that combo makes the ball shot higher and into you?
 

SystemicAnomaly

Talk Tennis Guru
Really cool post.

Also @SystemicAnomaly also a great analysis

Anyway it was all hit on the same court, same balls... so all this is the same.

But like i said

Shots are like


A shot = 6-7 feet net clearance, bounce 4-5 feet
B shot = 5-6 feet net clearance, bounce 5-6feet
C shot = 4-5 feet net clearance, bounce 5-6feet

Also in terms of speed

A shot seems slowest and more loopy while B has more penetration and pace and C has the most pace

All shots jump into you but B and C jump high into you while A jumps more low into you.

I know its hard to guestimate but if you were guessing, what would you say are the differences between the 3?
I had figured that you were probably talking about the same ball (type), same court & same conditions. We can ignore other spin types if we are considering pure topspin. Still, launch angle/trajectory, ball speed, topspin RPMs, and spin/speed ratio will all account for differences in net clearance and bounce height. These variations will result in difference in the steepness of the angle the ball has coming into the bounce -- and the post-bounce angle as well.

As for the point that John Y brought up, I recall some (approximate) numbers for a 120 mph Sampras serve. It would be interesting to see some number on RPMs as well

Initial serve speed: 120 mph
Pre-bounce speed: ~90 mph
Post-bounce speed: < 70 mph
Speed at other end: ~54 mph
 
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FiReFTW

Legend
Btw @JohnYandell

I dont completely agree with what you said that the ball doesnt jump and increase speed into you after the bounce when it has alot of spin, thats exactly what it does.

But remember we have to talk about horizontal speed here, because thats the speed with which an object moves towards you at.

We cant look at pure ball speed.

Like @SystemicAnomaly said with that Sampras stats, the ball constantly loses its speed, specially after the bounce.

However the ball also changes the angle at which it travels.

The more spin the more ball dips down into the court and the more speed it retains after the bounce.

The less speed the more gradual it drops and the less speed it retains after the bounce.

So we have to consider this aswell.

A ball hit at 75mph with little spin might have 40mph left after bounce while a ball with heavy spin might have 50mph left after bounce.

But more importantly, the little spin ball drops down gradual due to gravity while heavy ball gets pulled down more and thus its trajectory just before bounce is very vertical and traveling down.

So even if the ball itself has more speed prior to bounce than it has after, its traveling down into the court so the horizontal speed (with which its coming at you) at that moment is very low since all the speed is going down into the court, but after it bounces it starts traveling much more horizontal again towards you so the speed at which it travels towards you (not pure ball speed) gets increased by alot.

Thats why a heavy spin ball shoots towards you and picks up alot of speed.

Not pure ball speed, but speed at which its traveling towards you on a horizontal plane.
 

user92626

Legend
Fire

Power creates speed (velocity). After leaving the racket (the source of power), there's no other source of power to add to the ball, how's it going to increase its speed? On contrary there are only "against" forces to reduce its power, ie air, the ground. So, the ball doesn't increase speed after it leaves the racket, unless there's another source of power to aid it.

But, 'jumping' is different. The ball can store up a ton of energy and release it by counteracting with the ground and the result is a higher bounce. An example of this is anyone can smash a ball to the ground and have it bounce up a lot higher.

Same thing with spin. The ball can store up a lot of energy and then release it unevenly and create more spin. Think car accidents. A car can move straight and collide against another (bigger) mass unevenly and begin to spin.
 

FiReFTW

Legend
Fire

Power creates speed (velocity). After leaving the racket (the source of power), there's no other source of power to add to the ball, how's it going to increase its speed? On contrary there are only "against" forces to reduce its power, ie air, the ground. So, the ball doesn't increase speed after it leaves the racket, unless there's another source of power to aid it.

But, 'jumping' is different. The ball can store up a ton of energy and release it by counteracting with the ground and the result is a higher bounce. An example of this is anyone can smash a ball to the ground and have it bounce up a lot higher.

Same thing with spin. The ball can store up a lot of energy and then release it unevenly and create more spin. Think car accidents. A car can move straight and collide against another (bigger) mass unevenly and begin to spin.
I dont think you read my post well enough.

The ball itself keeps losing speed constantly after it leaves the racquet.

But the speed at which the ball travels TOWARDS YOU is not only based on ball speed but also the path and angle at which it travels.

A heavy spin ball might have

80mph speed at start
65mph prior to bounce
50mph after

But prior to bounce it dips into the court, so while it may have 65mph at that point, the ball is dipping down at a sharp ange, and is traveling more DOWN than FORWARD,so its FORWARD speed or how fast it travels TOWARDS YOU is a very small fraction of that.

Then as it bounces it starts traveling up and then towards you , so while it may have only 50mph now compared to 65mph prior to bouncing its traveling towards you now compared to down into the court, hence the speed its moving towards you is actually much greater.

Thats why it "picks up speed"
Or jumps into you

Ball speed itself is lower than prior to bounce, but its traveling faster at you than prior to bounce.

I hope its understandable what I mean now
 
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FiReFTW

Legend
Only shot spot could answer this debate. But have to doubt horizontial speed increases--whatever that means...
If the ball travels completely vertical it can have infinite speed and its going to travel at zero speed towards you.

Well a heavy topspin shot dips down into the court and at that point its speed towards you is small since it travels down at that split second, then as the ball bounces it bounces forward again.

And thats why it appears that the ball picks up alot of speed after bounce.



At the point where red arrow is ball dips down into the court, so alot of its speed is going down into the ground and very little is going forward towards you.
 

FiReFTW

Legend
Its like if you spin the ball to 3000rpm somehow and drop it down on the ground in a straight downward line, it would be moving straight down and all its speed would be vertical while horizontal speed would be 0.

But as it bounces the spin would grip the surface and ball would mova forward towards you hence moving towards you at a greater speed than when u dropped it down, even tho the speed of the ball would be surely slower after bounce than bafore, but it would he moving faster towards you tham before.

Same concept here just that obviously the ball is not dipping so much that its traveling completely downward on groundstrokes, but some heavy spin shots can still dip down at an extremely downward angle, thats why the heavier the spin the more it appears that the ball jumps into you after bounce.
 

SystemicAnomaly

Talk Tennis Guru
@FiReFTW @Hmgraphite1 @Kevo
I think there is a level of spin so high the ball doesn't lose speed post bounce as would normally happen, but will accelerate after bouncing. Especially on a grippy surface like a hard court
The physics tells us that there is a very high rate of spin where a tennis ball, theoretically, can have a greater horizontal speed (horizontal component of velocity) after the bounce than prior to the bounce. However, I don't believe that these conditions have ever been met in the real world on the tennis court. According to the calculations, for a given set of conditions in the Scientific American article below, a topspin ball would need to exceed 7200 RPM (120 revs/second) in order to see an increase in horizontal speed. The fastest spin rates observed in tennis -- Nadal (topspin Fh), Sampras (2nd serve), Federer (Bh slice) -- have been around 5200 RPM, possibly 5400 RPM. I believe that @JohnYandell can confirm this observed spin rate.

I don't believe that there are any conditions where the total speed of the ball after a bounce will equal or exceed its speed prior to the bounce.

https://www.scientificamerican.com/article/experts-tennis-topspin-ball/
 
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FiReFTW

Legend
@FiReFTW @Hmgraphite1 @Kevo


The physics tells us that there is a very high rate of spin where a tennis ball, theoretically, can have a greater horizontal speed (horizontal component of velocity) after the bounce than prior to the bounce. However, I don't believe that these conditions have ever been met in the real world on the tennis court. According to the calculations, for a given set of conditions in the Scientific American article below, a topspin ball would need to exceed 7200 RPM (120 revs/second) in order to see an increase in horizontal speed. The fastest spin rates observed in tennis -- Nadal (topspin Fh), Sampras (2nd serve), Federer (Bh slice) -- have been around 5200 RPM, possibly 5400 RPM. I believe that @JohnYandell can confirm this observed spin rate.

I don't believe that there are any conditions where the total speed of the ball after a bounce will equal or exceed its speed prior to the bounce.

https://www.scientificamerican.com/article/experts-tennis-topspin-ball/
Thats true but the ball will still move towards you faster after bounce than just before, since just before bounce the ball is traveling down into the court so its movement towards you will drastically decrease for that moment where it gets pulled down.

Agree?
 

SystemicAnomaly

Talk Tennis Guru
@FiReFTW @JohnYandell

It is normal for a topspin ball to have a greater spin rate post-bounce than pre-bounce -- it occurs in most situations, I believe. And most balls with backspin will reverse its spin after the bounce to become topspin. Backspin balls that bounce backward actually have topspin in a reverse direction (but to the ball striker it still "appears" to be backspin).

The vertical component of velocity (vertical speed) of the ball will decrease and increase during its flight because of gravity. As the ball rises, its vertical speed diminishes until it is ZERO at the peak of its bounce. It then increases again as it falls. It achieves a relative maximum as the ball contacts the ground. However, the post-bounce vertical speed will be less than its pre-bounce vertical speed. The vertical speed loss, on the bounce, will be less for a superball than for a tennis ball. But there will still be some amount of loss. I'm not aware of any spin conditions that will alter this.

As mentioned in post #45, the horizontal speed of the ball is always less post-bounce than pre-bounce in actual tennis play. Sometimes, it seem to be going faster, but that is an illusion. It only appears or feels that it is going faster, at times, because the horizontal speed has not decreased as much as it does on most other shots.

http://www.tennisindustrymag.com/articles/2004/04/follow_the_bouncing_ball.html
.
 

SystemicAnomaly

Talk Tennis Guru
Thats true but the ball will still move towards you faster after bounce than just before, since just before bounce the ball is traveling down into the court so its movement towards you will drastically decrease for that moment where it gets pulled down.

Agree?
No, I don't believe that what the links in post #45 and #47 are saying at all. For a ball that is dropping nearly vertical, the vertical speed is much greater than the horizontal speed. But I think that the horizontal (forward) speed after the bounce does not increase (IRW) if I'm reading these articles correctly. Perhaps you can point to where they say otherwise.

"Therefore, if the topspin is large enough so that 2πRF is greater than Vcm, the horizontal component of the ball's velocity will increase after the bounce. How fast must the ball be spinning for 2πRF to be greater than Vcm? For a typical ground stroke with a horizontal velocity of 25 meters per second, a ball of radius 0.033 meter will have to be spinning at greater than 120 revolutions per second."
 
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Keendog

Semi-Pro
@FiReFTW @Hmgraphite1 @Kevo


The physics tells us that there is a very high rate of spin where a tennis ball, theoretically, can have a greater horizontal speed (horizontal component of velocity) after the bounce than prior to the bounce. However, I don't believe that these conditions have ever been met in the real world on the tennis court. According to the calculations, for a given set of conditions in the Scientific American article below, a topspin ball would need to exceed 7200 RPM (120 revs/second) in order to see an increase in horizontal speed. The fastest spin rates observed in tennis -- Nadal (topspin Fh), Sampras (2nd serve), Federer (Bh slice) -- have been around 5200 RPM, possibly 5400 RPM. I believe that @JohnYandell can confirm this observed spin rate.

I don't believe that there are any conditions where the total speed of the ball after a bounce will equal or exceed its speed prior to the bounce.

https://www.scientificamerican.com/article/experts-tennis-topspin-ball/
How very Chas of you.

If you're expecting a large loss of speed after bounce and it doesn't it will give the appearance of speeding up whether literally does or doesnt. It's the feeling of being rushed in your stroke we are talking about
 
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