Optimum Racquet Balance for Performance - New Racquet Spec Data for ATP Pros

[travlerajm]

These results suggest that the optimum MR^2 value for a (strung) racquet is about 385 kg-cm^2.

http://postimage.org/image/1oaun2gdg/


The data are based on the specs posted by Jura for the 81 ATP players who used the French Open tournament stringing service in 2005.

Jura's unstrung specs have been converted to estimated strung specs, adjusting for string type, tension, string gauge, and string pattern.
http://tt.tennis-warehouse.com/showthread.php?t=48880

Six years have passed since 2005, so nearly every player has peaked by now, meaning the results are unlikely to change much more over time.

Enjoy.

Also, for two closely related threads, see:
http://tt.tennis-warehouse.com/showthread.php?t=387805

http://tt.tennis-warehouse.com/showthread.php?t=390065

[travlerajm]

Reserved for info on how data was processed

[travlerajm]

Reserved for analysis of results:

Player MR^2 values:

Moya 447
Mantilla 400
Knowle 400

Kiefer 399
Kuerten 397
Patience 395
Benneteau 392
Soderling 392

Grosjean 384
Agassi 384
Koubek 384
Robredo 383
Sluiter 383
Ferrer 382
Ventura 382
Gaudio 381

Canas 378
Sanchez 377
Sargsian 377
Ginepri 377
Sanginetti 376
Mathieu 375
Wawrinka 375
Saretta 372
Karlovic 372
Andreev 371
Nadal 370
Luczak 370

Massu 369
Monaco 369
Serra 368
Volandri 366
Bhupathi 366
Woodbridge 366
Garcia-Lopez 366
Blake 365
Vliegen 365
Saulnier 364
Bjorkman 364
Rusedski 363
Burgsmuller 362
Mirnyi 362
Nieminen 361
Schuettler 361
Nestor 360

Squillari 360
Carlsen 360
Haehnel 359
Roger-Vasselin 359
Mahut 358
Martin 358
Davydenko 356
Ancic 353
Horna 353
Acasuso 353
Beck 351
Rochus 350

Gonzalez 350
Wessels 350
Johannson 350
Devilder 350
Stepanek 349
Brian, B 349
Tipsarevic 347
Tursunov 347
Ullyett 347
Llodra 347
Tsonga 347
Djokovic 345
Brian, M 345
Spadea 345
Arthurs 344
Malisse 343
Clement 342
Srichaphan 342
Zimonjic 342
Di Pasquale 341
Melzer 338
Behrend 334
Black 333
Schalken 322

[Bartelby]

So on that basis if you know the value for all the up and coming players, then you could use that for predictive purposes?

[travlerajm]

Originally Posted by Bartelby

So on that basis if you know the value for all the up and coming players, then you could use that for predictive purposes?

Yes, but there are always exceptions.

I've been using this formula for 5 years.

For example, I was expecting Tsonga to struggle more than he has, since his MR^2 value is low. Djokovic too.

I think these 2 players defied the rule because (A) they have higher swingweights than their MR^2 values would suggest, and (B) they are exceptionally athletic.

I think the formula is most accurate for predicting success of players who are not especially gifted physically -- those that rely on consistency and accuracy rather than exceptional athleticism or dominating serve. I successfully predicted that Ferrer and Robredo would have nice careers, since they have MR^2 values in the apparent optimal range. Soderling is a another who I was expecting to perform well.

[TennisMaverick]

Originally Posted by travlerajm

Yes, but there are always exceptions.

I've been using this formula for 5 years.

For example, I was expecting Tsonga to struggle more than he has, since his MR^2 value is low. Djokovic too.

I think these 2 players defied the rule because (A) they have higher swingweights than their MR^2 values would suggest, and (B) they are exceptionally athletic.

I think the formula is most accurate for predicting success of players who are not especially gifted physically -- those that rely on consistency and accuracy rather than exceptional athleticism or dominating serve. I successfully predicted that Ferrer and Robredo would have nice careers, since they have MR^2 values in the apparent optimal range. Soderling is a another who I was expecting to perform well.

Can you tell us where to find these Jura specs?

[TheLambsheadrep]

strange

my head ti. carbons (12oz, 5 pts headlight) had (.340194278 kilograms)(32.7025 centimeters)^2 = 363.817

and my head twin tube tour radical OS's (12.6oz, 9 pts headlight) had (.357203991 kilograms)(31.4325 centimeters)^2 = 352.858

so my ti. carbons, a racket sold in Target (even though it is a 102 sq in Ti. Radical) are closer to greatness than one of the regarded best, if not the best, OS racket of all time?

[Hidious]

travlerajm, you must get criticized non-stop about the claims you make but i have to say, i love reading about your findings even though i have no idea if it's genius work or complete non-sense. For now, it's entertainment

[travlerajm]

Originally Posted by TennisMaverick

Can you tell us where to find these Jura specs?

Link added to OP.
http://tt.tennis-warehouse.com/showthread.php?t=48880

[SFrazeur]

Can anyone translate this discussion into layman's English?

-SF

[travlerajm]

Originally Posted by SFrazeur

Can anyone translate this discussion into layman's English?

-SF

Multiply the mass (M) of the racquet (in kg) times the square of the distance (R) from the from the butt to the balance point (in cm). This gives you the MR^2 value.

The dip in the graph at MR^2 = 385 shows that ATP players whose racquets have MR^2 value of about 385 tend to have much better rankings than ATP players whose racquets are outside the apparent optimum.

For example, players with MR^2 between 380 and 390 have average career best ranking of 15, while players with MR^2 of <350 have average career bests ranking of about 50.

[TheLambsheadrep]

travlerajm, what do you think about the results I posted above?


And I've also been trying to get you to help me with my situation.

I have 3 1998 Twin Tube Tour OS Radicals and 3 Ti. Carbon rackets. I have measured the weights and balances of all rackets, and for the TT Tours I have two at 12.6oz and around 9 points headlight, and the other one at 12oz and 6-7 pts hl. For the Ti's, I have two at 12oz and about 5 points headlight, and the other one at 11.8oz and 1-2 pts hl. I have protection tape on all of the bumpers and tournagrip on all the base grips (gamma contours).

-are these differences in weight and balance normal?

-should I try to get all 6 frames to have the same weight and balance, or just to have each group of 3 have their own same specs?


I've read "A polarized racquet is done by adding weight at 12 and the same weight under the butt cap. It provides poor stability and poor control on volley, less power, increased spin." ---> I want at least the 2 groups of rackets to have the same balance and weight. along with that, I would really like to add lead in a way to increase spin production and/or decrease power. so is the polarized set up the way to go? will it actually bring down my volleying and return-of-serve abilities?

Also, xFullCourtTenniSx said in regards to a polarized racket, "Because a majority of the added weight is placed towards the poles of the racket (at 12 o'clock with counterbalancing in the buttcap), the SW2 range is reached more quickly, resulting in a low static weight racket. However, as a result of the lower static weight (less power from mass) and increased spin production, lower tensions are usually required to make up for the overall lack of depth and power (which further assists in spin generation)." is he saying polarized=low powered because of generally lower racket weights? are my rackets at 12oz or 12.6oz already to heavy to have the low powered affects of a polarized set up?

[travlerajm]

Originally Posted by TheLambsheadrep

travlerajm, what do you think about the results I posted above?


And I've also been trying to get you to help me with my situation.

I have 3 1998 Twin Tube Tour OS Radicals and 3 Ti. Carbon rackets. I have measured the weights and balances of all rackets, and for the TT Tours I have two at 12.6oz and around 9 points headlight, and the other one at 12oz and 6-7 pts hl. For the Ti's, I have two at 12oz and about 5 points headlight, and the other one at 11.8oz and 1-2 pts hl. I have protection tape on all of the bumpers and tournagrip on all the base grips (gamma contours).

-are these differences in weight and balance normal?

-should I try to get all 6 frames to have the same weight and balance, or just to have each group of 3 have their own same specs?


I've read "A polarized racquet is done by adding weight at 12 and the same weight under the butt cap. It provides poor stability and poor control on volley, less power, increased spin." ---> I want at least the 2 groups of rackets to have the same balance and weight. along with that, I would really like to add lead in a way to increase spin production and/or decrease power. so is the polarized set up the way to go? will it actually bring down my volleying and return-of-serve abilities?

Also, xFullCourtTenniSx said in regards to a polarized racket, "Because a majority of the added weight is placed towards the poles of the racket (at 12 o'clock with counterbalancing in the buttcap), the SW2 range is reached more quickly, resulting in a low static weight racket. However, as a result of the lower static weight (less power from mass) and increased spin production, lower tensions are usually required to make up for the overall lack of depth and power (which further assists in spin generation)." is he saying polarized=low powered because of generally lower racket weights? are my rackets at 12oz or 12.6oz already to heavy to have the low powered affects of a polarized set up?

I would recommend experimenting on one racquet until you find specs that you like, and only then go through the trouble of matching all of your frames to that spec.

For info on how to tune your racquet with lead tape, do a search for MgR/I to find my posts on the subject.

[TennisMaverick]

Originally Posted by travlerajm

Link added to OP.
http://tt.tennis-warehouse.com/showthread.php?t=48880

Thanks....great thread.....make sure to ignore the haters when they come-out to criticize your results....the mods ignore the attackers and tend to focus more on the counter-attackers.

[shadowshifter]

Interesting thread! Any reason why you've posted about optimizing MR^2 instead of MgR/I? (Presumably since the data you linked doesn't have swingweight?) Or would you say both should be optimized?

[travlerajm]

Players with corresponding MR^2 values added in post 3.

[travlerajm]

Originally Posted by shadowshifter

Interesting thread! Any reason why you've posted about optimizing MR^2 instead of MgR/I? (Presumably since the data you linked doesn't have swingweight?) Or would you say both should be optimized?

I believe that the MR^2 value is loosely related to both the swingweight and the MgR/I value. If you optimize SW at about 360 (which tends to give maximum ball velocity on the serve) and optimize MgR/I for the forehand at about 20.8 (which I believe is optimum for a 6'2"-tall player with an eastern or semi-western forehand), and use a frame in the 12.5-13 oz weight range, you end up with MR^2 of about 385.

Also, I plan to add data with ATP Pro MgR/I values to this thread soon.

[shadowshifter]

Originally Posted by travlerajm

I believe that the MR^2 value is loosely related to both the swingweight and the MgR/I value. If you optimize SW at about 360 (which tends to give maximum ball velocity on the serve) and optimize MgR/I for the forehand at about 20.8 (which I believe is optimum for a 6'2"-tall player with an eastern or semi-western forehand), and use a frame in the 12.5-13 oz weight range, you end up with MR^2 of about 385.

Also, I plan to add data with ATP Pro MgR/I values to this thread soon.

Hmm, interesting. Quick question about how to calculate MgR/I: why does I = SW + 20MR - 100M? And how would you adjust it for a two handed backhand? Thanks!

[travlerajm]

Originally Posted by shadowshifter

Hmm, interesting. Quick question about how to calculate MgR/I: why does I = SW + 20MR - 100M? And how would you adjust it for a two handed backhand? Thanks!

The SW is measured from an axis 10cm from the butt end. Since the axis of rotation for the wrist is approximately even with the butt end of the racquet, you need to use the parallel axis theorem to convert the moment of inertia about the 10-cm axis (i.e., the SW) to the moment of inertia about the butt end (i.e., I).

Using the Parallel Axis Theorem and simplifying terms gives the equation above.

To use MgR/I for the 2hb, you can use the 10-cm axis because the left wrist (the top hand) is where the rotation is.

So substitute the SW for I, and substitute R - 10cm for R.

So Mg(R-10)/(SW).

For my 2hb, I find Mg(R-10)/(SW) is optimized when it equals about 22.5, or sometimes 22.6.

Since I know that my MgR/I for my forehand is optimized at about 21.0, it turns out that my 2hb will always have the optimized value (22.5) when R = about 31.75cm (or 32.0cm for Mg(R-10)/(SW) = 22.6.)

Once you tune MgR/I for your forehand, you can try tuning your 2hb by tacking weight to the end of the butt, which will reduce your backhand MgR/I without affecting your forehand much.

[shadowshifter]

Nice, thanks!