travlerajm

07-23-2011, 12:01 PM

After some further analysis of pro racquet specs data, here is a new very interesting (and very statistically significant) result showing that ATP Pros with racquet MgR/I value in the apparent optimum range (20.6-21.2) tend to have better rankings.

http://s1.postimage.org/gx1qb684/Slide1.jpg (http://postimage.org/image/gx1qb684/)

Notes:

1. This dataset is for all of the Top-50 players with mass, balance, and swingweight data posted on Greg Raven's web site - 33 players are included in the analysis.

2. Only 2 players from Greg's site (Djokovic and Federer) were excluded from the analysis, due to large discrepancy between Greg Raven's data and TTW poster FabFed's apparently authentic measurements. If these players have swingweights within the the ranges of (352-366 for Djokovic) and (346-359 for Federer), they would be in the "optimized' group.

3. To adjust for wrist band use, a 0.2 'correction factor' has been added to the MgR/I value for all players found to be wearing wrist bands during matches in their peak years (or when the measurement was taken). The correction factor is needed to account for the extra mass of approximately 20g acting about 5cm beyond the wrist axis of rotation.

4. Kafelnikov's specs were assumed to be unstrung, and strung specs were estimated. Since he falls in the middle of the "optimized" group, error in the estimate of his stringbed weight will make no difference in the result of the analysis.

5. g was assumed to be equal to 980.5 cm/s^2

6. M = Racquet mass in kg

7. R = Distance from balance point to butt end in cm

8. I = Swingweight about butt end of racquet, converted from measured 10-cm axis swingweight (SW) using the parallel axis theorem, where I = SW + 20MR - 100M.

Players included:

<20.6 Group (n=14):

Chardy Clement Nadal Dent Arazi Gasquet Benneteau Tarango Moya Gicquel Murray Gambill Soderling Karlovic

20.6-21.2 ("Optimized" Group, n=12):

Pioline Ivanisevic Agassi Sampras Rafter Kafelnikov Davydenko Melzer Stepanek Kuerten Nalbandian Safin

>21.2 Group (n=7):

Krajicek Schalken Cahill Rusedski Ilie Lee Mirnyi

For 2 closely related threads, see:

http://tt.tennis-warehouse.com/showthread.php?t=387805

http://tt.tennis-warehouse.com/showthread.php?t=387620

http://s1.postimage.org/gx1qb684/Slide1.jpg (http://postimage.org/image/gx1qb684/)

Notes:

1. This dataset is for all of the Top-50 players with mass, balance, and swingweight data posted on Greg Raven's web site - 33 players are included in the analysis.

2. Only 2 players from Greg's site (Djokovic and Federer) were excluded from the analysis, due to large discrepancy between Greg Raven's data and TTW poster FabFed's apparently authentic measurements. If these players have swingweights within the the ranges of (352-366 for Djokovic) and (346-359 for Federer), they would be in the "optimized' group.

3. To adjust for wrist band use, a 0.2 'correction factor' has been added to the MgR/I value for all players found to be wearing wrist bands during matches in their peak years (or when the measurement was taken). The correction factor is needed to account for the extra mass of approximately 20g acting about 5cm beyond the wrist axis of rotation.

4. Kafelnikov's specs were assumed to be unstrung, and strung specs were estimated. Since he falls in the middle of the "optimized" group, error in the estimate of his stringbed weight will make no difference in the result of the analysis.

5. g was assumed to be equal to 980.5 cm/s^2

6. M = Racquet mass in kg

7. R = Distance from balance point to butt end in cm

8. I = Swingweight about butt end of racquet, converted from measured 10-cm axis swingweight (SW) using the parallel axis theorem, where I = SW + 20MR - 100M.

Players included:

<20.6 Group (n=14):

Chardy Clement Nadal Dent Arazi Gasquet Benneteau Tarango Moya Gicquel Murray Gambill Soderling Karlovic

20.6-21.2 ("Optimized" Group, n=12):

Pioline Ivanisevic Agassi Sampras Rafter Kafelnikov Davydenko Melzer Stepanek Kuerten Nalbandian Safin

>21.2 Group (n=7):

Krajicek Schalken Cahill Rusedski Ilie Lee Mirnyi

For 2 closely related threads, see:

http://tt.tennis-warehouse.com/showthread.php?t=387805

http://tt.tennis-warehouse.com/showthread.php?t=387620