Category Archives: Kinesiology
When we do the testing and “number taking” for our demo racquets, we try to think as the consumer may think and include comments that may help the consumer make the best decision.
We do not want to make these posts so dull that you go to sleep, but data is essential, so we are going to include it…so stay awake!
Data is particularly relevant to the Prestige Series from Head.
This review is for the Prestige Tour, and it points to the differences between Prestige racquets that may go unnoticed or misunderstood.
The Prestige Tour is a 99 (645 cm²)square inch racquet with an 18 x 19 string pattern. If you have read the post on the Prestige MP, you may wonder, what’s the difference?
You may notice that the Prestige Tour has one (1) fewer cross string. Not a big deal. You may see that the Prestige Tour has one (1) square inch larger head size. Also, not a big deal. What you may not notice is the Prestige Tour has an in-plane stiffness of 400, and the Prestige MP has an in-plane stiffness of 359. That is a big deal! Even with a bigger head and fewer strings, the Prestige Tour has a higher string bed stiffness than the Prestige MP. The higher the in-plane stiffness, the less the racquet will “bend” during impact.
The Prestige Tour is more stiff overall (62 v 58) than the Prestige MP, and the 21.5mm beam contributes to that stiffness.
So, take a look at the numbers for this racquet to see if you can find other exciting differences!
Racquet Model Head Graphene 360+ Prestige Tour
Reference Tension 55 lbs - 24.9 kg
Victrex PEEK fiber Experimental 7718
Machine Used True Tension Professional
ASPS, RDC 55
ASPS, FlexFour 71
Racquet Flex, RDC 62 - After stringing
Racquet Flex, FlexFour 49
Weight, Grams 325
Weight, Ounces 11.46
Balance, mm 327
Balance, Inch 12.87
Length, Cm 68.6
Length, Inch 27.008
Head Width 9.56
Head Length 13.12
Head Area, cm2 635.3
Head Area, Sq. Inch 98.5
Beam Width, mm, Shaft, Center, Tip 21.5, 21.5, 21.5
In Plane Stiffness, Pounds/In 400.0 Lbs/In.
In Plane Stiffness, Kg/cm 181.4 Kg/cm
Number of Main Strings 18
Number of Cross Strings 19
Ratio Cross/Mains .690
Main String Grid 7.81
Cross String Grid 10.00
Density (% of head filled with string) .724
Average Cross String Space .526
Average Main String Space .396
Dynamic Tension, Kp, ERT 35
Dynamic Tension, Lbs/in 195.7
First Moment, Nm .819
Polar Moment 334
Torsional Stability 18
Swing Weight, Kg/cm2 316
Swing Weight, Ounces 11.15
Swing Weight Calculated 347.5
Power, RDC 46
Control, RDC 55
Manueverability, RDC 76
Power, Calculated 1929.2
Head Points 4.88 (negative = head heavy)
Head Weight, % 47.7%
Center of Percussion 20.8
Dwell Time, ms, No Swing 8.58
Efective Stiffness - lbs 29.1
K, Lb/In (SBS) RDC 176.3
Recoil Weight 150.9
Twist Weight 222.7
End Weight 131.7
Tip Weight 195.3
9 O'Clock 100.7
3 O'Clock 101.4
Butt Cap 124.0
2019 came and went in a blur! In a few days it will 2020 and with it will come some exciting new tennis stuff, for sure!
I am not so good at predicting things but I do it anyway! Here are a few predictions I will make for 2020:
- Tennis racquets will become more expensive, but only slightly.
- On-line sales of tennis racquets will increase. See this previous post.
- Customer satisfaction with on-line sales will decrease.
- Small specialty tennis shops will be the source of information, then #2, and then #3.
- Players will stick with a racquet longer, making customizations as needed.
- String and stringing will become a more important component of a racquet purchase. See below!
- Tennis related injuries will continue to be a problem for the sport going forward.
Thank you for thinking about the “long term” for all tennis players!
There are no bad strings just bad applications!
The right equipment is crucial to the long term enjoyment, and winning, of tennis!
The local representatives I deal with are committed to our “well being” even though some may feel like they are facing “extinction”!
An excellent example of what we are talking about just walked in! Two (2) new racquets so poorly strung it is shocking!
The customer is having serious arm issues with an excellent racquet, with a terrible string setup! But the string setup is probably considered by many to be the ultimate combination, that is RPM Blast in the main and VS Touch in the cross! That combination is coming out in a few minutes! No more polyester!
The quality of the stringing is what is so wrong! Had you or I received this racquet, we would have returned it at once! Why? Because it exemplifies the attitude of so many stringers that is “who cares”!
Happy New Year!
The essential function of string in your tennis racquet is to return energy to the ball as it collides with the racquet. It is evident that if there is no string or a broken one, the racquet can not do what it is intended to do, and your shot is going nowhere or worse, everywhere!
There are about thirty (30) string brands, and each brand has about ten (10) different models, and maybe three (3) different colors, so there are nine hundred (900) possible selections! Nine hundred is way too many strings!
You and we need to consolidate string data so we can make the right decision for you, your playing style, and your physical capabilities.
We test every string for elongation, creep, (stability), with a little bit of elasticity data observed. This testing returns our exclusive Power Potential© for each string, and that is the basis of our decision-making process. Naturally, the higher the elongation, the more power the string will return to the ball, and conversely, the lower the power potential, the less power that “can” be generated. You can observe this fundamental by dropping a tennis ball on a concrete floor and then on a strung tennis racquet from the same drop height and see which one bounces the highest.
I use “can” because power, to a great extent, comes from how hard you swing the racquet, which, of course, brings the prospect of overdoing it and subsequent injury! A low power string demands a more powerful swing that involves the entire arm, hips, and legs.
Low power, in the form of a stiff string, has been associated with control, therefore, the increased use of stiff strings. However, with stiffness comes another downside, and that is stability. Stiff strings typically lose tension quickly and need to be changed frequently. So here is the real problem; the string may not be broken, but it is not playing well at all. There is a difference between durability and performance! If your goal is long term performance, a stiff string is not the answer.
What, then, is the answer?
Choose a string with an elongation of 10% or higher! Oh, great! You say. How am I going to know that!
Well, beginning January 1, 2020, I will be posting the power potential of every string we have tested over the years! There are over 500 items on the current list sorted by brand. The color coding is RED if 5% or less, GREEN if 10% or higher, and BLUE for everything else. Note, however, that natural gut is included in this data and will probably not reach the 10% Power Potential© threshold, but is still the best performance string available. This is due to the dynamic properties of the natural fibers, so, until there is a separate classification gut will be included as is.
A previous post, “What is Soft?” goes into graphical detail.
As new strings are added, some older ones may be deleted because they are no longer manufactured. However, some very old ones may remain due to their “legacy” status. This chart is a preliminary format but will get us map toward the right decision!
It should be no surprise that this model is the heaviest of the VCore Pro Series! However, I can’t stress enough the need to demo this racquet and feel what the weight will do for your game!
Of course not everyone will want a racquet of this weight but just trying it will give you some idea of what weight can do for you. Maybe not 330 (unstrung) but a little added weight nonetheless.
That makes the 310 (unstrung) version of this racquet a “standout”, and you can see the review here.
About this racquet, Yonex says “for intermediate to advanced players looking to play aggressively with control and feel”.
To achieve this combination Yonex has incorporated a “lock booster” grommet system that promotes string contact for effecient energy transfer”.
Namd™ graphite fibers are incorporated into the throat area allowing the racquet to flex even under the heaviest of hits!
To top it off Yonex has added a vibration damping mesh in the grip pallet area to filter out unwanted vibrations.
All said, this thin beam (20.0mm) racquet with a 16×19 string pattern is a players dream! So, don’t dream about it…demo it and decide for yourself!
|Racquet Model||Yonex VCore Pro 97|
|Reference Tension||55 lbs - 24.9 kg|
|String||Pro Evaluation String 1.20mm|
|Machine Used||True Tension Professional|
|Racquet Flex, RDC||62 - After stringing|
|Racquet Flex, FlexFour||48|
|Racquet - In Plane Stiffness||373.2 lbs/Inch|
|Head Area, cm2||611.3|
|Head Area, Sq. Inch||97|
|Number of Main Strings||16|
|Number of Cross Strings||19|
|Main String Grid||7.00|
|Cross String Grid||9.62
|Density (% of head filled with string)||.709|
|Average Cross String Space||.505|
|Average Main String Space||.438|
|Dynamic Tension, Kp, ERT||34|
|Dynamic Tension, Lbs/in||190.16|
|First Moment, Nm||.847|
|Swing Weight, Kg/cm2||327|
|Swing Weight, Ounces||11.53|
|Swing Weight Calculated||354|
|Head Points||6.93 (negative = head heavy)|
|Head Weight, %||46.8%|
|Center of Percussion||20.9|
|Dwell Time, ms||8.74|
|Efective Stiffness - lbs||28.6|
If you read our recent post about “How to Demo a Racquet,” you may be incentivized to do it!
So while you are at it try one of our performance racquets setup with MonoGut ZX or ZX Pro (thinner) to get the maximum performance from the racquet.
Ashaway MonoGut ZX and ZX Pro have been one of our most popular strings for well over five (5) years!
Top players have been using it, but now the word is spreading that is not just for “the good player” but for everyone! We are very sensitive to injuries and injury prevention, so that is why we recommend MonoGut ZX to almost all players. The durability and feel of this string are unique, and, MonoGut ZX and ZX Pro is a monofilament but is PEEK and no polyester.
As with any string, some will not want to change, but if you are looking for a new racquet, why not demo a racquet setup with MonoGut ZX or ZX Pro?
Ashaway MonoGut ZX and ZX Pro come in Black and Natural and 16 (1.27mm) and 17 (1.24mm) gauge.