Category Archives: Kinesiology

The Elephant in the Room!

I suspect we all have heard that expression!

It means there is something that everyone tries to ignore, but it is too large to do so!

I recently read an article in Racquet Sports Industries authored by Georgetta L. Morque. The title is “Tackling Tennis Elbow.” Tennis elbow is an important topic and deserves much attention. Georgetta is writing about ways to mitigate tennis elbow after the fact.

So, here is the elephant in the room; STIFF string!

 

Let’s try to prevent tennis elbow, so it does not need to be treated!

When we say stiff, it means a string with less than 4% elongation at 60 pounds which is our testing parameter. Most strings, and for this discussion, strings exhibiting that property will be monofilament PET-based (polyester).

Fully understanding this required a lot of testing, both lab and play, for many playing styles and racquets. To make a long story short, as a racquet technologies business, we decided not to promote polyester strings for most players. That sounds silly, but why take a chance when you don’t have to!

Our success is based on helping you, the player, perform the best you can, so it does not make sense to promote something contrary to that philosophy. Probably 75% of our clients have come to us for something different, so we have a “head start.” 

So why do so many players use it or want to use it? 

We believe it is because they have not been exposed to alternative string materials. Some outstanding players at the pro level use it, so it must be good, and it is for about 10-11 games. Of coursemanufacturers and marketers of polyester string stand to make a nice profit! It is in their best interest to promote products by adding some terminology and material to make the string less stiff.

A polyester string is deficient in power and needs to be walloped, and the harder it is hit, the stiffer it becomes, which is the problem. Developing bodies can’t tolerate that level of impact for long.

Please let us know your experience with strings of any type!

 

Head Boom Team L 2022

Like the Head Boom Team 2022, the Head Team L 2022 has been much anticipated!

Finally, a 107 square inch head without the ridiculous thick beam and ultra-lightweight, a legitimate “tweener”!

The Boom Team L has the highest power level assigned to recent Head racquets coming in at “900”, compared to the Boom Team at 800 and the Boom Pro at 400. If a power racquet is what you are looking for, this may be a good choice!

The Boom Team L is a slightly longer racquet at 27.35 inches. This increase in length increases the swing weight without adding weight. You can think of swing weight as “leverage.”

The Boom Team L incorporates all the newest materials and design chops of the viral Boom Pro and Boom MP.

The specifications will give you a better idea of where this racquet may fit your game.

ManufacturerHead
Racquet ModelHead Boom Team L 2022
Reference Tension56 lbs - 25.4 kg
String
Head Reflex MLT 17
Machine UsedTrue Tension Professional
Static
ASPS, RDC45.0
ASPS, FlexFour55.0
Racquet Flex, RDC63 - After stringing
Racquet Flex, FlexFour46.0
Racquet - In Plane Stiffness339.8 lbs/Inch
Weight, Grams290
Weight, Ounces10.23
Balance, mm353
Balance, Inch13.90
Length, Cm69.5
Length, Inch27.362
Head Width10.15
Head Length13.25
Head Area, cm2679.5
Head Area, Sq. Inch105.6
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.643
Main String Grid7.90
Cross String Grid10.56
Density (% of head filled with string).792
Average Cross String Space.556
Average Main String Space.494
Dynamic
Dynamic Tension, Kp, ERT31
Dynamic Tension, Lbs/in173.39
First Moment, Nm.805
Polar Moment331
Torsional Stability18
Swing Weight, Kg/cm2313
Swing Weight, Ounces11.04
Swing Weight Calculated361.4
Power, RDC53
Control, RDC48
Manueverability, RDC78
Power, Calculated 2139.2
Head Points-1.73
Head Weight, %50.8%
Center of Percussion20.7
Dwell Time, ms9.48
Efective Stiffness - lbs26.3
K, Lb/In144.23
Recoil Weight129.71
Twist Weight221.11
End Weight 97.7
Tip Weight 192.3
9 O'Clock93.0
3 O'Clock92.8
Butt Cap103.8

Head Boom Team 2022…BOOM!

It is here, and I bet you heard another big BOOM recently!

The Head Boom Team 2022 has arrived and is ready for you to try! The Boom Team is a valuable addition to the Head lineup.

For years players have been asking for a 102 square inch racquet that has the “player” characteristics they wanted.

Player characteristics can mean different things to different players, but here is what the Head Boom Team 2022 has:
A fairly thin beam
A thin head cross-section
A modified box beam shaft cross-section

This racquet continues with Graphene and fresh Auxetic material that has been popular in the Boom Pro and Boom MP!

All specifications are in the chart below but suffice to say; this is a significant step in the right direction!

Looking at the inside of the shaft, you will notice the transitional shape from a thin box beam into a slightly thicker trapezoidal beam.

The head shape also continues with the broader upper section like the Boom Pro and Boom MP. Most “aggressive” shots are hitting the string bed in this area, so giving it more energy makes sense!

The density of the string in that area should contribute to good string life.

The first thing you notice upon pickup (first moment) is the weight distribution. While this is still a “headlight” model (see the specs below), the weight is toward the tip of the racquet.

We have had great results with the Boom Pro and Boom MP in both “retail” and full custom racquets, so, If you are considering a racquet upgrade, this one should be on your list!

ManufacturerHead
Racquet ModelHead Boom Team 2022
Reference Tension55 lbs - 24.9 kg
String
Head Reflex MLT 17
Machine UsedTrue Tension Professional
Static
ASPS, RDC48.0
ASPS, FlexFour64
Racquet Flex, RDC61 - After stringing
Racquet Flex, FlexFour45.0
Racquet - In Plane Stiffness389.6 lbs/Inch
Weight, Grams300
Weight, Ounces10.58
Balance, mm337
Balance, Inch13.27
Length, Cm68.6
Length, Inch27.008
Head Width9.97
Head Length13.065
Head Area, cm2659.7
Head Area, Sq. Inch102.3
Number of Main Strings16
Number of Cross Strings19
Ratio Cross/Mains.642
Main String Grid7.80
Cross String Grid10.80
Density (% of head filled with string).845
Average Cross String Space.568
Average Main String Space.500
Dynamic
Dynamic Tension, Kp, ERT33
Dynamic Tension, Lbs/in184.57
First Moment, Nm.786
Polar Moment320
Torsional Stability15
Swing Weight, Kg/cm2305
Swing Weight, Ounces10.76
Swing Weight Calculated340.7
Power, RDC46
Control, RDC54
Manueverability, RDC83
Power, Calculated 1921.4
Head Points1.89
Head Weight, %49.1%
Center of Percussion20.8
Dwell Time, ms9.18
Efective Stiffness - lbs26.9
K, Lb/In153.85
Recoil Weight138.76
Twist Weight222.21
End Weight 114.3
Tip Weight 187.8
9 O'Clock91.5
3 O'Clock93.6
Butt Cap114.8

SBS…what is it and why should we care?

We have made several posts regarding SBS, which is “String Bed Stiffness” and this is another one!

If you read this post we really need your comment(s), really!

String bed stiffness is the “feeling” when the ball hits the string on a tennis racquet.  Due to the various string materials there will be “soft” and “hard” feelings.  But wait, there’s more!

The string bed is made up of several strings, some longer called the Main string (M)and some shorter called the Cross string(X).  Using “reference” tension each of the sets of string will be pulled at the same machine setting!  It the machine is set at 50 pounds the tension head will stop pulling when it feels 50 pounds of resistance, regardless of what he tension inside the racquet head may be.

SBS is the most effective data for comparing tennis racquet stringing!

Let’s say you come into the world headquarters and we ask you what SBS you would like to have?  Would you know?  Probably not and not many would!  We have grown up using the term “reference tension”, not SBS.

Reference tension is “number” you would ask your racquet technician to set the stringing machine tension system on.  That number will probably be between 30 and 60 pounds (≈13 to 26 Kilo).

So, depending on many other variables, such as string material, string pattern, stringing machine, stringer technique, etc., you can end up with may different versions of the same “reference tension”.

A better way, and one we have been using for over thirty (30) years, is SBS but not everyone has bought into the concept, even though a qualified racquet technician will have a way to measure SBS!  Maybe because it is too much trouble to figure out what your desired SBS from machine X would be from machine A!  It is not!

There have been several really good SBS data collection devices but they have been difficult to use, and pricy!  Not to mention gigantic!

A call to action!
So here is where you come in,

Would you purchase a SBS data collection device?

How much would you pay for such a device?

Would you prefer a mechanical device or an electronic device?

The device must be portable, that is easily carried in a racquet bag or backpack

    Yes or It doesn’t matter

It must be easy to use.

If you use an SBS device would you use a racquet technician that did not know what SBS is or how to measure it?

Thank you for adding your comments to this discussion!  It is important stuff!

 

Head Lynx Touch! Two for One?

Several weeks ago we received the first sets of Head Lynx Touch 17 gauge strings.  Yesterday we received the Lynx Touch 16 gauge version and want to share the differences…numerically!

Quickly, this string is composed of two (2) separate but “combined” filaments.  So, is this a monofilament or a multifilament?  The numbers indicate it reacts like a monofilament as we have become familiar with it.

Head Lynx Touch

Visually the string components are obvious.

The inner filament is black and the outer covering is translucent.

 

Let’s start with the 17 gauge version:

  Lynx Touch 17

The area under the heavy red lines is the “stress/strain” curve and we see that this string takes 23.5mm to reach the 50-pound mark.  This is just a number unless it is compared to other strings so it is neither good nor bad, right now!

You can see that the string will hold up to 149.8 pounds before it breaks.  This is tensile strength and may be important when considering the amount of “notching” that can occur.  The “knot” strength of this version is 132.4 pounds.

Now let’s look at the 16 gauge version:

Lynx Touch 16

The difference is subtle.  The 16 gauge version is a little stiffer (expected) and a little stronger in tension  (also expected).  The “knot” strength of this version is 133.6 pounds.

What is interesting is the “grouping” of the stress/strain cycles on both strings.  They indicate a good elasticity.  The closer to the “zero” point on unloading the better!

In our opinion, both versions of the string would be considered “stiff” and suitable for the player looking for a stiff but stable string as our creep test confirmed.

If you currently use stiff strings and would like better consistency this would definitely be a candidate ./