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

Discussion in 'Racquets' started by travlerajm, Jul 4, 2011.

  1. travlerajm

    travlerajm Hall of Fame

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

    http://postimage.org/image/1oaun2gdg/
    [​IMG]

    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
     
    Last edited: Feb 29, 2012
    #1
  2. travlerajm

    travlerajm Hall of Fame

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    Details of data

    Reserved for info on how data was processed
     
    #2
  3. travlerajm

    travlerajm Hall of Fame

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    Analysis of data

    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
     
    Last edited: Jul 4, 2011
    #3
  4. Bartelby

    Bartelby G.O.A.T.

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    So on that basis if you know the value for all the up and coming players, then you could use that for predictive purposes?
     
    #4
  5. travlerajm

    travlerajm Hall of Fame

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    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.
     
    Last edited: Jul 4, 2011
    #5
  6. TennisMaverick

    TennisMaverick Banned

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    Can you tell us where to find these Jura specs?
     
    #6
  7. TheLambsheadrep

    TheLambsheadrep Professional

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    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?
     
    #7
  8. Hidious

    Hidious Professional

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    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 :)
     
    #8
  9. travlerajm

    travlerajm Hall of Fame

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    #9
  10. SFrazeur

    SFrazeur Legend

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    Can anyone translate this discussion into layman's English?

    -SF
     
    #10
  11. travlerajm

    travlerajm Hall of Fame

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    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.
     
    Last edited: Jul 4, 2011
    #11
  12. TheLambsheadrep

    TheLambsheadrep Professional

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    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?
     
    Last edited: Jul 4, 2011
    #12
  13. travlerajm

    travlerajm Hall of Fame

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    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.
     
    Last edited: Jul 4, 2011
    #13
  14. TennisMaverick

    TennisMaverick Banned

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    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.
     
    #14
  15. shadowshifter

    shadowshifter New User

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    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?
     
    #15
  16. travlerajm

    travlerajm Hall of Fame

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    Players with corresponding MR^2 values added in post 3.
     
    Last edited: Jul 4, 2011
    #16
  17. travlerajm

    travlerajm Hall of Fame

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    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.
     
    Last edited: Jul 4, 2011
    #17
  18. shadowshifter

    shadowshifter New User

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    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!
     
    #18
  19. travlerajm

    travlerajm Hall of Fame

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    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.
     
    Last edited: Jul 5, 2011
    #19
  20. shadowshifter

    shadowshifter New User

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    Nice, thanks!
     
    #20
  21. pudelko

    pudelko Rookie

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    How would you calculate the 10cm swingweight? Does the TW warehouse method with the swinging racquet and stopwatch do this? Or does it measure the swingweight at the buttcap?
     
    #21
  22. ben123

    ben123 Professional

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    uhm just btw tsongas mr^2 is not so low. maybe in juras specs, but some1 here on the forum posted (a few weeks ago) tsongas aero pro racket and specs and his mr^2 would be smth like 379-380

    and about djokovic i dunno^^

    also i agree with the post that this here is genius work or complete non sense haha :). hope its not bc my racket would be 382 :twisted:
     
    Last edited: Jul 5, 2011
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  23. TheLambsheadrep

    TheLambsheadrep Professional

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    so even though the 2 sets of rackets have different head sizes, you recommend matching them all?

    and i looked at your MgR/I posts, very interesting, I just don't know what you want me to look for/get out of it exactly

    when looking at a racket set up, is it swingweight or general weight that that causes the "low powered" attribute? Because a polarized setup allows someone to add less weight overall but increase swingweight more, while a depolarized setup does the opposite...
     
    Last edited: Jul 5, 2011
    #23
  24. SlowButSure

    SlowButSure New User

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    Big sample size problem here.

    Just from eyeballing, I'd venture the SD on the larger bins is a lot bigger than the smaller ones. Just happened there were no qualifiers playing with a racquet in the 380 range. Add one guy who's top rank is 150 to that group and the 'dip' completely disappears.
     
    #24
  25. Fuji

    Fuji Legend

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    I just tried MR^2 on my PSC6.1 and I got 353.3867.... How odd! I really like this system! I will try all my other sticks when I get the chance!

    -Fuji
     
    Last edited: Jul 5, 2011
    #25
  26. movdqa

    movdqa Legend

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    My previous racquet is 404 and my current is 350; talk about extremes. I do mean to make the current frames heavier but I'm just getting used to them stock first.

    Personally, I think that being anywhere close to anyone on that entire list would be great with me.
     
    #26
  27. whomad15

    whomad15 Semi-Pro

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    polarized makes your racquet more unsteady? I added weight at 10/2 and about the same in the handle and my racquet is the most stable thing I've ever played with. Plowthrough is great, but I lost some spin because, well, it's heavier than what I'm used to so I can't generate as much headspeed as before.
     
    #27
  28. TimothyO

    TimothyO Hall of Fame

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    To achieve a rating of 385 a 27" 10 point HL racquet would need to weigh 397.67g or about 14oz. Yikes! :)

    And a 345g racquet would need to be roughly 3pts HL to arrive at 385.
     
    Last edited: Jul 5, 2011
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  29. travlerajm

    travlerajm Hall of Fame

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    Trust, me. I have manipulated the data in many ways. The general trend is statistically significant, even when I filter out players outside the top 100, or top 200. Note that even if the mini-dip for the 380-390 bin disappears, there is still a statistically robust dip for the wider bin of players between 370-400.

    Note that all 81 players had rankings within the top 250. The real driving reason for the trend is the relative percentages of players in each bin that have top 10 rankings.

    I will present wider-binned results with error bars soon. Interestingly, the statistically significant trend (i.e., that having MR^2 > 375 correlates with better performance) is present in the WTA player data also, which I will present soon too.

    Showing log-mean or geometric mean rankings rather than arithmetic mean would probably be more appropriate (because that desensitizes the result to poorly ranked outliers), but I wanted to make the result less confusing to the layperson. The result looks similar either way.
     
    Last edited: Jul 5, 2011
    #29
  30. movdqa

    movdqa Legend

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    Could you also post the average weights and swingweights along with the bins?
     
    #30
  31. travlerajm

    travlerajm Hall of Fame

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    Interesting that Greg Raven's 2009 specs for Djokovic have his balance about the same, but the mass about 20g heavier (giving him MR^2 of 368 ).

    Either he made a huge change to his specs between 2005 and 2009, or the raw data has an error. I think a 20g change seems huge for someone who was rapidly scaling the world rankings to #3 in the world during that span. My guess is that Jura's spec is in error.

    I'll have to think about how I should handle this type of discrepancy -- it might make sense to adjust the dataset, since I trust Greg's measurements, and whether or not Djokovic changed his specs between 2005 and 2009 not, he achieved his career best ranking with the more recent specs.

    If Tsonga has been actually using MR^2 of ~380, it makes more sense to me why my prediction that I posted 5 years ago based on his apparent sub-optimal racquet specs was in error for him too.
     
    Last edited: Jul 5, 2011
    #31
  32. TimothyO

    TimothyO Hall of Fame

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    A value ranging from 370 to 400 means a limited universe of potential weight and balance combinations for racquets likely to competitive at the pro level. For example, you probaly won't find very many light frames.

    Weight and balance are closely related physical capabilities. Has anyone gathered data such as player height and weight/BMI and compared it to these values?
     
    #32
  33. TennisMaverick

    TennisMaverick Banned

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    The game has changed tremendously since '05. If you had data from Oz, rather than Roland Garros or Wimbledon where players adjust their frames more, your formula should produce much different data.
     
    Last edited: Jul 5, 2011
    #33
  34. TheLambsheadrep

    TheLambsheadrep Professional

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    It is odd, and so are my results:

    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 i guess 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?
     
    #34
  35. Fuji

    Fuji Legend

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    Weird!

    My PSC6.1 is 13.4oz and 32.5cm balance point I believe. (I'm too lazy to convert that to HL points.) I think it's one of the best sticks I've ever even played with, and alas, it's no where near greatness. :( LOL!!!

    -Fuji
     
    #35
  36. TheLambsheadrep

    TheLambsheadrep Professional

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    if its 27 in, its between 5 and 6 pts headlight
    i like the paint job, like its on fire!
     
    Last edited: Jul 5, 2011
    #36
  37. Fuji

    Fuji Legend

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    Sorry! it's actually 31.0cm. It'd help if I could read a tape measure properly LOL!

    -Fuji

    EDIT: This almost makes my new number 365! :)
     
    Last edited: Jul 5, 2011
    #37
  38. TheLambsheadrep

    TheLambsheadrep Professional

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    ya, and 10-11 pts headlight

    interesting that my racket and your racket have a similar final number when yours is much heavier and headlight
     
    #38
  39. Hidious

    Hidious Professional

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    I've also transferred jura's list to an excel sheet and the averages are 338.64g and 31.18 balance. That's unstrung. Add about 16g and 1cm for strings
     
    #39
  40. Hidious

    Hidious Professional

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    I remember some posts here about Djokovic "going back" to his old serve motion with the old, heavier setup. Some pictures show significantly long lead tape strips on each side of Djovokic's Speed PJ, i'm not sure if he always had those and never really could find out if those claims were correct.
     
    #40
  41. Fuji

    Fuji Legend

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    Agreed! It's quite interesting that even though our rackets are greatly different, they are quite similar in numbers!

    -Fuji
     
    #41
  42. travlerajm

    travlerajm Hall of Fame

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    #42
  43. TheLambsheadrep

    TheLambsheadrep Professional

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    #43
  44. DEH

    DEH Rookie

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    Do you have the WTA data yet?
     
    #44
  45. Recon

    Recon Semi-Pro

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    Travelajm I would like for you to help me out. I'm too confused by the math but I have a microgel prestige mid and would like to put it in mr.safins range. How much leadtape and wear would I put it. It was reported that he actually switched to the microgel version so I know its possible. If you help thanks a ton. If not, I respect that too.
     
    #45
  46. movdqa

    movdqa Legend

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    TW has an online customizing tool (TW University link) that can show you where to place the lead given static weight, swingweight and balance of the two frames.

    I think that most of the Head pros use Pro Stock frames though. You could certainly match your MGPM to Mr. Safin's weight, balance and swingweight but your frames could have other differences in construction.
     
    #46
  47. DannyJK

    DannyJK New User

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    I just want to say thanks to Travlerajm for making such a cool formula, trying to get close to the optimal Mr2 value has made my racquet feel much better I think. although it is really heavy now and kinda tires me a little, the pro's are that it seems more stable and has more plowthru. Im definately going to keep experimenting via this formula and I may check out some other ones too.

    but for now I say Cheers to Travlerajm for his theory which I believe seems to show a good account in practical application!!
     
    #47
  48. TheLambsheadrep

    TheLambsheadrep Professional

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    just looking back through my data and found something interesting: if I take the weight that I use now (12.7oz, closer to the TT Tour Radical at that time but what I use on everything now), and the balance of the ti carbons at the earlier time (5 pts headlight), i get (.360038944 kilograms)x(32.7025 centimeters)^2 = 385.0449. I have the balance on all my rackets at 8-9 pts headlight (maybe just slightly into 10) to make them more whippy. So what would changing them from 9pts hl to 5pts hl do to the feel/whippiness?

    also, is achieving MR^2 to = 385, or MgR/I to = 20.7-21.1 better?
     
    Last edited: Feb 15, 2012
    #48
  49. TheLambsheadrep

    TheLambsheadrep Professional

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    Also (and I hope travlerajm will comment on this), I'm finding that the balance of the racquet affects the MR^2 more than mass does. I have an actual chart, but based on my calculations, head lightness goes down around .4pts for a .1oz decrease in mass (ex. @13oz, to get an MR^2 of 380, a racquet needs to be 6.8598 points headlight. if you go from 13 to 12.9oz, the balance needs to go from 6.8598 points headlight to 6.4724 points headlight to keep MR^2 at 380). I thought more pros would have a more head light balance, i mean at 13oz to get an MR^2 of 390 the racquet is only about 5.5pts head light. But where is the boarder between a neutral balance and head light on the point scale?

    And again, I have the balance on all my rackets at 8-9 pts headlight (maybe just slightly into 10) to make them more whippy. So what would changing them from 9pts hl to 5pts hl do to the feel of the swing/whippiness of the swing?

    also, is achieving MR^2 to be = 385, or MgR/I to be = 20.7-21.1 more desirable?
     
    #49
  50. akamc

    akamc New User

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    Travlerajm, how does MR^2 conceptually differ from SW and where one would one matter more than the other ? I know how the formulas differ and the 10 cm difference between the assumed axis of rotation... but could you maybe verbalize the difference in ways that we traditionally describe how a racquet feels?

    Also, what is the direction of causality in this correlation ? Does using a MR^2 of near 385 really optimize any player's results ? Or is it that only elite players have the requisite power/technique/timing so that they can properly use a MR^2 of 385 ?

    As somebody else pointed out, it would be interesting to see the equivalent research applied to the WTA data, since that would probably be a more realistic comparison for the majority of players on this board :) . Any plans to do that ?
     
    #50

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