Category Archives: Kinesiology

Know Your String!

Several years ago, when we were beginning to increase the use of Ashaway MonoGut ZX and ZX Pro, it was not unusual to get a call from a client saying, “my coach says I should not be using polyester!” We could not agree more, and you are not using polyester!

You are using PEEK polymer! This string material was, and still is, referred to as Zyex with polymer production capabilities of Victrex in England.

Given the appearance of MonoGut ZX, Babolat Origin, and a few other non-polyester monofilament strings, it is not easy to distinguish these from stiffer polyester material strings. So know your string!

Single strand (monofilament) strings will have a gleaming surface unless they have been through a “roughing” process. So will monofilament strings of different materials. It is hard to tell just by looking, and that is what can create some confusion on behalf of the coach and subsequently, the player. So know your string!

If your racquet technician does not put a label on the racquet that identifies the material (or string), then be sure to ask what material you are using. The material choices may be natural gut, Zyex (PEEK), Nylon, and Polyester. The string construction may be referred to as a monofilament, multi-filament, single wrap, etc. however, the material will probably be one of these four.

Know your string! If you are unsure, contact your racquet technician or “Ask John” on this site, and we will try to help.


Weight is Your Friend!

If you have been following the Racquet Quest Podcast you know how much we rely on weight to mitigate some poor shot execution or physical issues!

So, don’t be surprised if that position continues for a while!  It is majorly important now that we are beginning to play (openly) again!

It is not clear to me why some players object to even discussing weight let alone add it to their racquet!

The latest podcast episode, The String Holder – Part Two, focuses on three (3) players of about the same age and skill and looks at the differences in racquet setup including weight.

If weight is so scary why do most racquets have a bunch of it hidden away from us?

This is a Tecnifibre racquet however most performance racquets will have a similar setup.  Game Improvement (ultralight) racquets, typically, will not!

What you see in that groove is lead!  If you flip the racquet over you will find the same thing on the other side!  Lot’s of lead means lots of weight, relatively speaking!

If we wanted to reduce the weight of this racquet we could remove some or all of the weight without affecting the swing weight very much.  The static balance, however, would be very different.  That is why we don’t rely on “balance” as a performance metric.

In the case of this racquet, we are printing a grip pallet that will replace the original pallet but be heavier so we can remove some of the lead weight to make the new version the same weight if we wanted to.  We don’t want to!



Tale of the Tapes!

Probably the most common “customization” on tennis racquets is the addition of weight! In most cases, that is a good thing. Weight is your friend!

Weight, in this case, is confined to swing weight and of course, overall weight and the placement of that weight and the format being used. We will see two (2) options and try to decide which is the best format.

Option number one below is the most common format for adding weighted tape. You can see that the tape is narrow strips that are placed on either side of the string bed. Even though the length of the tape is different on each racquet, the swing weight is the same on all of them.

Common Weighted Tape Format

Common Weighted Tape Format

The advantage of this format is that the weighted tape can easily be removed or more added if desired without affecting the formatting.

Option number two is rarely requested, but it represents the best-looking result.

Not Easily Modified Tape Placement

Not Easily Modified Tape Placement

However, this format requires much more time and is not easily removed or modified.

This format requires the grommet set to be removed, which, in most cases, is not a problem. In some cases, it will be a big problem! So be sure this is what you want!

The tape must be carefully trimmed between strings and removed without damaging the strings if modification is required to reduce weight. Doing this is not hard but does require a little more time. Adding weight requires removing the string and grommet set if the format is to remain the same, i.e., no narrow strips laid on top of the current tape.

Whichever option you choose will provide the performance boost you want!

Let us know which option you would choose in the comments below!

Head Graphene 360+ Speed PWR

I suppose you have a pretty good idea what PWR means, right?  Well, you would be correct!  The Head Graphene 360+ Speed PWR is just that at a calculated power value of 2297.5!  Compare that to the calculated power value for the Head Graphene 360+ Speed Lite of 1838.3!  Twenty percent (20%) more powerful than the Lite!

This is what a 115 square inch head size can do for a racquet!  The strings are quite a bit longer and more widely spaced which contributes to power, and comfort.

This head size is normally referred to as a “game improvement” racquet and relegated to those players that were not too athletic and/or didn’t want to exert too much energy on each stroke.  In other words slow and short swings.

I am not sure that is the case with this racquet!  Sure it has a big head and a thick beam but it sure does feel good when picked up (first moment)!

If we were going to recommend this racquet I would suggest some weight added to the rear end.  The head does not need any additional weight.

Head Graphene 360+ Speed PWR

As I am working on this post I realize how much trouble it is to switch between racquet reviews for comparison so I am including a link to the Head Graphene 360+ Speed Series Comparison.

Racquet ModelHead Graphene 360+ Speed PWR
Reference Tension56 lbs - 25.4 kg
Victrex PEEK fiber Experimental 7718
Machine UsedTrue Tension Professional
ASPS, FlexFour59
Racquet Flex, RDC64 - After stringing
Racquet Flex, FlexFour59
Weight, Grams276
Weight, Ounces9.74
Balance, mm352
Balance, Inch13.86
Length, Cm69.4
Length, Inch27.32
Head Width10.50
Head Length13.81
Head Area, cm2734.8
Head Area, Sq. Inch113.9
Beam Width, mm, Shaft, Center, Tip26, 26, 28
In Plane Stiffness, Pounds/In550.5 Lbs/In.
In Plane Stiffness, Kg/cm 249.7 Kg/cm
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.640
Main String Grid8.56
Cross String Grid11.15
Density (% of head filled with string).759
Average Cross String Space.532
Average Main String Space.535
Dynamic Tension, Kp, ERT33
Dynamic Tension, Lbs/in184.57
First Moment, Nm.764
Polar Moment324
Torsional Stability18
Swing Weight, Kg/cm2306
Swing Weight, Ounces10.79
Swing Weight Calculated342.0
Power, RDC49
Control, RDC52
Manueverability, RDC83
Power, Calculated 2297.5
Head Points-1.57 (negative = head heavy)
Head Weight, %50.7%
Center of Percussion21.3
Dwell Time, ms, No Swing9.18
Efective Stiffness - lbs27.4
K, Lb/In (SBS) RDC153.85
Recoil Weight132.95
Twist Weight225.40
End Weight 92.6
Tip Weight 184.4
9 O'Clock91.1
3 O'Clock90.6
Butt Cap94.2


Head Graphene 360+ Prestige Mid

The Head Prestige Mid is, in my view, the quintessential Prestige! This Prestige is the tennis racquet you would buy even if you don’t play tennis! It would sit right next to your Porsche 550 that you don’t drive much, but both make you feel really good!

The latest edition of the Prestige Mid is the Graphene 360+ Prestige Mid, and it carries on the iconic tradition of all previous models and looks better doing it, in my opinion.

In left image, you can see the overall color scheme of all of the new Prestige series, but you can’t see the detail of the “cap system” that is different than the other three (3) Prestige models.

The lower image shows the transition location.  But why?

Mid Cap System Transition




I think it is just a matter of weight. The cap system on the Mid stops halfway down the head instead of all around as on other models.

This slight reduction in weight allows for more customization options and this is a very customizable racquet.
So, if you are interested in an “iconic” racquet to place next to your 550, this is the one!

What could be better than arriving at the courts in your 550 and pull out your Prestige Mid racquet!

Game, Set, Match!

Racquet ModelHead Graphene 360+ Prestige Mid
Reference Tension55 lbs - 24.9 kg
Victrex PEEK fiber Experimental 7718
Machine UsedTrue Tension Professional
ASPS, FlexFour72.0
Racquet Flex, RDC63 - After stringing
Racquet Flex, FlexFour36
Weight, Grams344
Weight, Ounces12.13
Balance, mm317
Balance, Inch12.48
Length, Cm68.5
Length, Inch26.97
Head Width9.25
Head Length12.67
Head Area, cm2593.4
Head Area, Sq. Inch92.0
Beam Width, mm, Shaft, Center, Tip20, 20, 20
In Plane Stiffness, Pounds/In428.6 Lbs/In.
In Plane Stiffness, Kg/cm 194.4 Kg/cm
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.615
Main String Grid6.87
Cross String Grid8.88
Density (% of head filled with string).663
Average Cross String Space.467
Average Main String Space.429
Dynamic Tension, Kp, ERT37
Dynamic Tension, Lbs/in206.9
First Moment, Nm.834
Polar Moment341
Torsional Stability15
Swing Weight, Kg/cm2326
Swing Weight, Ounces11.50
Swing Weight Calculated345.7
Power, RDC47
Control, RDC53
Manueverability, RDC69
Power, Calculated 1888.9
Head Points8.03 (negative = head heavy)
Head Weight, %46.3%
Center of Percussion21.1
Dwell Time, ms, No Swing8.43
Efective Stiffness - lbs29.9
K, Lb/In (SBS) RDC182.69
Recoil Weight166.4
Twist Weight221.8
End Weight 146.7
Tip Weight 197.3
9 O'Clock104.6
3 O'Clock102.8
Butt Cap134.6