How can flexible racquets be powerful?

[Ashley D]

Originally Posted by LeeD

As per usual, you see only one way, black or white.
But what is more powerful?
Are you isolating the racket characteristics from the PLAYER's kinetics?
CAN they be judged separately, or does one actually become linked with the other?
Say a baseball batter look for pure power for hitting home runs. Can he just look for a heavier bat? For more power? Or can he use a lighter bat, choke up on it, and still get the power?
What do you think? I know BarryBonds uses the lightest bat of all the homerun hitters, and get's his power from bat speed, not bat kinetic energy.
So there may be more than one way to look at the power equation.

And what would be the best way, in your opinion? I don't see any problems with Jacks information. He's talking about keeping extraneous variables (such as your "PLAYER'S kinetics", lol) consistent, and then measuring the impact of flexibility when these are kept equal. This is, after all, what I was asking.

[marosmith]

So then what would be the advantage of a stiff racket?

[Ashley D]

Originally Posted by marosmith

So then what would be the advantage of a stiff racket?

I guess it's just a difference in whatever feel you prefer?

[ChicagoJack]

Originally Posted by marosmith

So then what would be the advantage of a stiff racket?

Hi marosmith -

I will admit to a huge personal bias here. Not a big fan of stiff racquets. My brief stint with the 2012 PD last summer left me with my first ever case of TE after 30+ years on the court. But I will do my best to answer the question squarely. If you want to generate more ball velocity, you have two choices. You can swing faster, and a lighter racquet will help you do this, or you can swing a heavier racquet the same speed. (velocity = mass times acceleration)

Light Racquet, Fast Swing: Swinging the racquet faster has an added bennie in that you will gain additional spin out of the bargain. However, if you are swinging so fast that you pop out of your comfort zone and start making errors because you are swinging wildly that is not good. The other problem is that when making a racquet very light, it becomes unstable. One way to counter this instability in the lower swingweights is to make it a bit stiffer. Take a popular low sw frame like the 2012 PD for example. I can't think of any frame that is more stable at such a low SW of 308. If you compare the PD to something like the Donnay Gold 99, which has a super thin 16/18/18 mm beam, it will give you a bit more juice at very the top of the hoop for 10 less sw units. It's kind of a wash everywhere else. You could look at this like "free power" since the PD is easier to swing at 308 vs 318. However, if you compare a 2012 PD to a really thoughtfully engineered frame like the Becker Delta Core London, or the 105 Red, You'll find that those racquets have similar power everywhere except for the very tip, for the price of just 3 more SW digits. So the question becomes, is that little bit of "free power", a good trade for reduced arm comfort? For me, not in a million years. For somebody else, maybe yes. Is the PD worthy of the "Rocket Launcher" moniker? Nope, not in the slightest. It's complete myth. Not a "Rocket Launcher" by any measurable, comparable means. Some free power, but not much.

Heavier Racquet, More Flex, Same Swing: you wont need to swing quite as fast, which means that you might be able to control the racquet a bit more and reduce unforced errors. Your big bennie out of the bargain will be added stability on off center hits, which you will experience as a bigger sweet spot, and additional arm comfort. A reduced swing speed will not do any favors to spin production, but high sw also implies more dwell time which is spin friendly.

My last image showed four very different flexes and swingweights. The one below hints at the incremental advantage gained with a stiff racquet, when the SW are very similar.

-Jack

[ChicagoJack]

Originally Posted by Ashley D

And what would be the best way, in your opinion? I don't see any problems with Jacks information. He's talking about keeping extraneous variables (such as your "PLAYER'S kinetics", lol) consistent, and then measuring the impact of flexibility when these are kept equal. This is, after all, what I was asking.

H Ashley -

Yes, well said. When a player is talking about racquet power, what he usually has in mind is the inherent power of one racquet compared to another, which is completely separate and distinct from whatever skill level or technique the player brings to it. It's not that players don't matter. Skill matters a great deal. It's just that to understand racquet power, you have got to understand the fundamental building blocks of ball to racquet impacts first.

-Jack

[Cengusiento]

Amazing posts ChicagoJack, very instructive, and also suits my personal experience.

I'm currently using a 2012 PD. The feel is that is one of the most powerful rackets I've ever used, but the fact is that when I want to hit a baseline winner it's easier with my flexy volkl powerbridge 10mid than with the 2012PD.

[dman72]

Originally Posted by ChicagoJack

Hi marosmith -

I will admit to a huge personal bias here. Not a big fan of stiff racquets. My brief stint with the 2012 PD last summer left me with my first ever case of TE after 30+ years on the court. But I will do my best to answer the question squarely. If you want to generate more ball velocity, you have two choices. You can swing faster, and a lighter racquet will help you do this, or you can swing a heavier racquet the same speed. (velocity = mass times acceleration)

Light Racquet, Fast Swing: Swinging the racquet faster has an added bennie in that you will gain additional spin out of the bargain. However, if you are swinging so fast that you pop out of your comfort zone and start making errors because you are swinging wildly that is not good. The other problem is that when making a racquet very light, it becomes unstable. One way to counter this instability in the lower swingweights is to make it a bit stiffer. Take a popular low sw frame like the 2012 PD for example. I can't think of any frame that is more stable at such a low SW of 308. If you compare the PD to something like the Donnay Gold 99, which has a super thin 16/18/18 mm beam, it will give you a bit more juice at very the top of the hoop for 10 less sw units. It's kind of a wash everywhere else. You could look at this like "free power" since the PD is easier to swing at 308 vs 318. However, if you compare a 2012 PD to a really thoughtfully engineered frame like the Becker Delta Core London, or the 105 Red, You'll find that those racquets have similar power everywhere except for the very tip, for the price of just 3 more SW digits. So the question becomes, is that little bit of "free power", a good trade for reduced arm comfort? For me, not in a million years. For somebody else, maybe yes. Is the PD worthy of the "Rocket Launcher" moniker? Nope, not in the slightest. It's complete myth. Not a "Rocket Launcher" by any measurable, comparable means. Some free power, but not much.

Heavier Racquet, More Flex, Same Swing: you wont need to swing quite as fast, which means that you might be able to control the racquet a bit more and reduce unforced errors. Your big bennie out of the bargain will be added stability on off center hits, which you will experience as a bigger sweet spot, and additional arm comfort. A reduced swing speed will not do any favors to spin production, but high sw also implies more dwell time which is spin friendly.

My last image showed four very different flexes and swingweights. The one below hints at the incremental advantage gained with a stiff racquet, when the SW are very similar.

-Jack

This is good stuff. It looks like the stiff racquet gives a slight boost at the top and bottom of the frame and that's pretty much it in terms of really significant differences.

You can also see how much more forgiving the oversize Prince is near the frame at 3 & 9, not really that much, but it gives you more than the stiffer frame.

[mongting]

Originally Posted by ChicagoJack

5. However, when we started firing real balls at real racquets and measuring rebound velocity, the results were shocking, and the old estimate formulas were thrown out the window pretty quickly. Here is a quote from Rod Cross speaking directly of that moment of astonishment I'm describing: Quote: " Figure 2 shows RP (Rebound Power) vs. swingweight for all racquets. The result is simply amazing. Instead of having the 268 dots scattered all over the place, the dots line up perfectly along four different curved lines. The four curves correspond to different racquet lengths. All racquets of the same length lie on the same curve, with short racquets having a bigger RP than long racquets. The result in Figure 2 shows that any two racquets of the same length and the same swingweight will have exactly the same RP, regardless of their weights and regardless of their balance points. The inbuilt power of a racquet in the middle of the strings therefore depends only on the length and swingweight of the racquet, and on nothing else." -- Rod Cross, Raw Racquet Power, Link [2]
Jack

So, from the link, the advantage of plus(longer) racket is only for the serve when you hit it near the tip . You get less rebound power than shorter racket. Is this a right statement?

[anubis]

Hey ChicagoJack, question for you:

Say I have a Head IG Radical MP and a Babo APD side by side. For a play test, I swing both racquets at the exact same swing speeds. Why would more shots stay in with the APD than with the Rad MP? If I swing the Rad MP slower, more shots stay in with it. But I have to consciously swing it more slowly. With the APD, i don't have to worry, if I swing fast or slow, the shots stay in.

I'm sure your answer is somewhere in your responses, but for some reason it's just not "coming together" in my mind. Can you help me a bit? Thank you

[dman72]

Originally Posted by anubis

Hey ChicagoJack, question for you:

Say I have a Head IG Radical MP and a Babo APD side by side. For a play test, I swing both racquets at the exact same swing speeds. Why would more shots stay in with the APD than with the Rad MP? If I swing the Rad MP slower, more shots stay in with it. But I have to consciously swing it more slowly. With the APD, i don't have to worry, if I swing fast or slow, the shots stay in.

I'm sure your answer is somewhere in your responses, but for some reason it's just not "coming together" in my mind. Can you help me a bit? Thank you

Completely different string patterns, so it could just be the topspin of the APD keeps the shots in.

[mongting]

Originally Posted by dman72

Completely different string patterns, so it could just be the topspin of the APD keeps the shots in.

I thought the same way.

[anubis]

Thanks. So if i was using an IG Rad Pro in place of the MP, then perhaps I could swing just as fast and still keep it in play?

[LeeD]

And here, we come right back to the PLAYER preference and his specific needs for his physiology, no matter what you would like to think otherwise.
My best illustration. PREDATOR. Do you think any of the other guys besides Jesse and Arnold could have carried a minigun?
Would Jessie be happy toting a MP-5 in 9mm?
Wouldn't the Indian guy be better served with a bow and a spear?
Back to specific tennis, whilch is easier for you to understand....
Say....BIG SHOW. What racket would you give him? A 10oz fly swatter or maybe a 14 oz real man's racket?\
How about ...,PeeWeeHerman? Would you arm him with a 14 oz flexi flyer, or would you give him a 9.6 oz stiff modern racket?
YOU CANNOT isolate the specifics of the player out of this equation!!!

[ChicagoJack]

Originally Posted by mongting

So, from the link, the advantage of plus(longer) racket is only for the serve when you hit it near the tip . You get less rebound power than shorter racket. Is this a right statement?

Hi Mongting -

Yeah, that's kind of confusing. I had to re-read that section 3 times the first time I read it for it to sink in properly. Here is the key quote about racquet length and rebound power.

Quote: "There is a simple reason that long racquets have a smaller RP. In order for a long racquet to have the same swingweight as a short racquet, weight has to move out of the head and relocated closer to the handle. Since RP is determined mainly by weight in the head, a long racquet must therefore have a smaller RP than a short racquet (at any given swingweight)."

Link [2] Raw Racquet Power, By Rod Cross
http://www.racquetsportsindustry.com...uet_power.html

Here is my translation of that quote.

If...

Racquet A: has a sw of 320, and is 27 inches.
Racquet B: has a sw of 320, and is 28 inches.

Then Racquet B must have less mass in the head of the frame.

Remember that sw is measured by clamping the racquet into the the RDC machine at 10 cm (about 4 inches up on the grip) and is rotated around that axis. So a 28 inch frame gets a boost in sw not from more mass in the head, but from the length of the frame. If you took a 27 inch frame with a 320 sw, and added another inch to it by sliding the buttcap down, you'd increase the swingweight dramatically (about 10 units for every 1/4 inch or so) with the end result of a racquet in the 360 range. So to get that back down to 320, you'd have to shift a bunch of mass out of the head, and back into the handle. That's why it's not uncommon to see extended length frames with balances of -16 points.

Now, let's put that into proper context. In the testing procedure, the racquets are not moving, balls are fired at the string beds of freely suspended frames. That's why longer frames with less mass in the head will show less inherent Rebound Power / ACOR. Out on the court, however, the racquet is moving. Swingweight is a terrible proxy for a real tennis swing, (because in a real swing the racquet is rotating around numerous axis points in the hips, shoulder, wrist and elbow, and undergoing several changes in elevation), but it's fairy easy to intuit that the extra SW you get from the extra length factors right back in once the racquet is moving. Once it factors back in, you are left with the same old conundrum... higher sw is harder to swing fast, but will assert more authority on the ball during the impact.

-Jack

[LeeD]

Tie that one to how good a racket feels on certain shots when you choke up an inch.

[yonexRx32]

Originally Posted by luvforty

excellent excellent point, and one that is almost always neglected, due to the lack of knowledge.

the resonance is important for both power and control..... if the shaft and the stringbed go out of wack, you can have hot/cold periods in the impact zone, giving unexpected results.

Please, educate us. Elaborate on that. Write down the equations. Where did you get your knowledge from?

[Ashley D]

Originally Posted by LeeD

My best illustration. PREDATOR. Do you think any of the other guys besides Jesse and Arnold could have carried a minigun?
Would Jessie be happy toting a MP-5 in 9mm?

And just like that all logic, reason and science flies out the window. I hate to be the one to tell you this LeeD......Predator is pretend.

[LeeD]

Another lesson gone over your head........
In 1970, I enlisted in the Army, for an 8 year enlistement. This one is true.
I was 5'10", about 125 lbs. The Army thought I was the PERFECT size for their needs in what I enlisted for. NOT to carry a SAW, not to be the grenadier, NOT to hump the ammo, but perfect for grunt and pointman.
One of my buds was 5'9" and 225lbs. They didn't plan on him at point or carry a M-16, they envisioned a humper, carrying the SAW or mortar, or even the radio.
Different jobs for different body builds.

[ChicagoJack]

Hi LeeD,

I was wondering if you might like to take a stab at answering Anubis's question. To somebody even mildy curious about the basic building blocks of ball-racquet collisions and racquet power (entirely separate from player skill) It wouldn't be hard to piece together. The clues are right there in my posts for anybody to see. For somebody who understands the fundamentals of racquet power intimately, a plausible answer is apparent immediately. All of your comments seem to indicate you find little value in separating the player from the racquet for 11 seconds to contemplate inherent racquet power. I think these concepts I've been discussing can be useful for figuring out on court scenarios such as the one Anubis is currently pondering.

-Jack

[LeeD]

Anubis's question could have many valid answers.
From preference, to grip size, to string tension and kind, balls used, air temps, style of swing, and a host of other factors.
We suspect Babs is barely stiffer, bigger beamed, so the ball should impart the strings quicker.
But does that equate to more topspin? And that is not always a set answer.
Some players prefer a stiffer racket. Some prefer a softer racket. We know this.
Have we seen Anubis hit? And can a vid really show something that a COACH might need several lessons to figure out? And we never claimed to be coach's.