Category Archives: Learning
Racquet & Tournament Management
Management is not just for adults! Juniors that play tournaments need to have some management skills! During this coronavirus slow down it is a good time to learn some of these management skills.
We see many different management slip-ups such as no racquets for the tournament tomorrow! All racquets have broken string and are at the bottom of a bag nobody wants to stick their hand into!
Juniors Management Tip #1:
Every Monday takes every racquet out of the bag. If one or more are broken leave them out of the bag.
Juniors Management Tip #2
To get some idea of how much longer the string may last simply try to move the 5th or 6th cross string by pulling up toward the top of the racquet. If you can not pull the cross string up it is time for stringing. If you are able to pull a cross string up pay attention to the “snap” it makes as you push it back into location. A serious “snap” indicates a deep notch.
Monofilament strings typically fail by notching which makes it difficult to move the cross strings. If your string is a multi-filament and looks like the picture on the left it is time to string!
Abrasion Fail Visual Test
Notching Visual Fail Test
What if neither of these conditions exists?
Every racquet in your bag should have a tag indicating when the racquet was last strung and if it has been more than one month it is time to string, period!
Just for fun you can go to our SFC function and get a good ideas as to how many times per year yu need to have your racquet strung.
I Get It! Maybe… or Maybe Not!
When we do a racquet review we try to deal with numbers! Static and dynamic numbers to be precise. We do this so each racquet can be referred to by properties and not just by subjective comments. Make no mistake, subjective comments are good and can be used in fact to generate numbers!
Here is an explanation of the numbers and what they can mean to you.
It is well known that 5 players will have 5, or more, different “comments”, so having numbers provide a database, or history, of what works for what player style. With that information, a new client can be playing with their “perfect” racquet is a very short time instead of trying a zillion different models.
This is important because players may not be using the best racquet for them because they rely on assumptions instead of numbers! The very worst assumption is “I need a light racquet because I am just getting back in the game”. The second worst assumption is “I need a big head with a big sweet spot because I am not very good”. The third worst assumption is “I don’t need very good string because I am not very good”.
Bogus assumptions, every one of them!
As we look over our client data some things are clear and should become performance metrics;
- Total weight should be not less than 10.5 ounces (300 grams).
- Swing weight should not be less than 10.5 ounces (300 grams).
- Torsional stability should not be less than 15 units (typically grams).
With these metrics, you are off to a great start with a new racquet, or if you are beginning a new racquet search these numbers will be helpful.
By The Numbers
Here we go with this numbers thing, again!
Our Racquet reviews are a bunch of numbers, but what do these numbers mean to you?
We have put together this table with a brief explanation of how each number can be used by you to understand how that property can be helpful.
If you see terms such as typical or normal, ignore them! With tennis players, there is no such thing as “typical and normal”!
If you need to be convinced, take a look at a previous post!
Please let us know if there is a number that needs more clarification or a number we are missing!
| Manufacturer | Yonex | What it Means |
|---|---|---|
| Racquet Model | Yonex VCore Pro 97 HD | Racquet being reviewed. |
| Reference Tension | 55 lbs - 24.9 kg | Stringing machine tension setting. Not, necessarily, the string bed stiffness. |
| String | Ashaway MonoGut ZX Pro | String brand name and gauge (Pro being 17Gauge) |
| Machine Used | True Tension Professional | Stringing machine used. |
| ASPS, RDC | 56 | The stiffness of all the strings as a unit. Normally between 30 and 65. |
| ASPS, FlexFour | 64.5 | The stiffness of the string bed as tested on this device. |
| Racquet Flex, RDC | 57 - After stringing | 50 is low (flexible) and 70 is high (very stiff). Clash 100 is 52 on this device. As is a Head Speed model. |
| Racquet Flex, FlexFour | 50 | 35 is low (flexible) 70 is high (very stiff). Clash 100 is 26 on this device. |
| Racquet - In Plane Stiffness | 353.8 lbs/Inch | This is how stiff the racquet head is across the middle. 300 is soft and 500 is very stiff. This affects the string bed stiffness. |
| Weight, Grams | 336 | 285 is light and 360 is heavy. 315 is minimum target weight for performance. |
| Weight, Ounces | 11.85 | The racquet weight in ounces, typically used in US. |
| Balance, mm | 322 | This is the center of gravity from the butt cap. If you put the racquet on a round rod this would be how much is hanging toward the butt cap. |
| Balance, Inch | 12.68 | This is the CG in ounces for US. Points head heavy or head light is part of this. |
| Length, Cm | 68.5 | This is the total length of the racquet and is the typical standard adult length. |
| Length, Inch | 26.968 | This is length in inches for the US. |
| Head Width, Inches | 9.57 | The inside width of the hitting area. |
| Head Length, Inches | 12.54 | The inside length of the hitting area. |
| Head Area, cm2 | 625.8 | The advertised hitting area in centimeters squared. |
| Head Area, Sq. Inch | 97.0 | The advertised hitting area in inches squared. |
| Number of Main Strings | 18 | The main strings are the vertical strings when looking at a standing racquet. Typically the longest strings. |
| Number of Cross Strings | 20 | The cross strings are the horizontal strings when looking at a standing racquet. Typically shorter. |
| Ratio Cross/Mains | .687 | The natural ratio of the string pattern (calculated). |
| Main String Grid | 7.25 | The total distance between right and left main string. |
| Cross String Grid | 10.18 | The total distance between the first cross string and the last cross string. |
| Density (% of head filled with string) | .783 | |
| Average Cross String Space | .509 | The higher this number the more the string will move. This number is used to help select the best string setup. |
| Average Main String Space | .403 | The higher this number the more the string will move. This number is used to help select the best string setup. |
| Properties of a moving racquet. | ||
| Dynamic Tension, Kp, ERT | 37 | This is the stiffness of a string bed in kilograms per centimeter based on a frequency. |
| Dynamic Tension, Lbs/in | 206.94 | This is the above converted to pounds per inch. |
| First Moment, Nm | .831 | This is how heavy the racquet feels in the hand. The higher the number the heavier the racquet will feel. |
| Polar Moment | 340 | This is the resistance to rotating about the center of the racquet on, say a mimes-hit. The higher the better. |
| Torsional Stability | 16 | This is the derived stability number. The higher the better within reason. Anything below 14 would need some help. |
| Swing Weight, Kg/cm2 | 324 | This is the "inertia" of the racquet and probably the most important number in the review! The higher the number the more momentum through the ball but less manueverability. |
| Swing Weight, Ounces | 11.43 | |
| Swing Weight Calculated | 348.4 | This number will be larger than the previous swing weight because it is calculated from the very end of the racquet as if there is no one holding it. A very important number. |
| Power, RDC | 42 | Calculated by the RDC. High is 100 |
| Control, RDC | 59 | Calculated by the RDC. High is 100 |
| Manueverability, RDC | 71 | Calculated by the RDC. High is 100 |
| Power, Calculated | 1740.5 | This number is calculated based on a bunch racquet properties, Including length. |
| Head Points | 6.46 (negative = head heavy) | This number is how positive or negative the balance is. A "point" is ⅛ of an inch so this racquet is a little over ¾ of an inch head light. |
| Head Weight, % | 47.0% | Calculated based on weight distribution and length. |
| Center of Percussion | 21.0 | This is the spot on the string bed that returns a "solid" hit. |
| Dwell Time, ms | 8.50 | This is how long the ball and string are in contact with no swing. A big swing will reduce this number by about half. |
| Efective Stiffness - lbs | 28.2 | This number is calculated from the string bed stiffness and the racquet stiffness. Anything under 30 will be "soft" feeling and over 35 will be "harsh". |
| K, Lb/In | 179.5 | This is how many pounds it takes to deflect the string bed one (1) inch. |
| Recoil Weight | 160.8 | This number is the racquets resistance to rotating backward. The higher the number the better for volleys. |
| Twist Weight | 230.8 | This is the racquets resistance to twisting in your hand. The higher the better. |
| End Weight | 139.8 | This weight is used to calculate the precise balance of the racquet. |
| Tip Weight | 196.2 | This weight is used to calculate the precise balance of the racquet. |
| 9 O'Clock | 100.4 | This is the weight of that position on the racquet head and is used for precise customization. |
| 3 O'Clock | 99.6 | This is the weight of that position on the racquet head and is used for precise customization. |
| Butt Cap | 135.6 | This is the weight of that position on the racquet and is used for precise customization. |
The Racquet Quest Podcast…update!
Thank you for listening to the Racquet Quest Podcast!
I am posting here to make an addition and a correction to a previous podcast, and this is quicker than waiting for a week or so for a new episode.
The “Stringing and Racquet Data” podcast was cut short, so I will finish it here.
We were talking about the three (3) scale system we use to determine the torsional balance. The racquet is weighed at the midpoint of the head at the “top” and “down,” and the butt cap is resting on the third scale, and that is called the “butt.”
I don’t recall the podcast numbers right off, so I will use numbers from another racquet to explain. The racquet is a Wilson Ultra 100. The “top” weight is 95.3 grams, the “down” weight is 96.0 grams, and the “butt” is 119.9 grams for a total of 311.2 grams (10.97 oz.). So you can see the difference between the “top” and “down” number is only .7 grams, which is about a quarter of the weight of a vibration damper!
However, if this number was over 5 grams, we may want to “match” the numbers a little more closely! But, what if we wanted to increase the “top” weight by a lot to have the head heavier on one side than the other side? Why? Maybe a “training” aid to remind the player to keep the head lower, for example. Our experience shows that a difference between the “top” and “down” of 6 grams is noticeable.
On the Yonex VCore Pro 97 – Racquet Review, I noticed after the fact that I had indicated the Ereca System calculated the balance (CG) to within one-tenth of a centimeter! That would be pretty good, but in fact, the Ereca System calculates to within a tenth of a millimeter! Very precise! As of now, the Ereca System does not calculate swing weight as I tried to correct on the podcast but wanted to confirm that point.
Thank you for visiting the Racquet Quest website and listening to the Racquet Quest Podcast! Please let me know if you have any questions and suggestions for exciting topics!
Racquet Quest, LLC
