PHYSICS OF TENNIS
The behaviour of racquets and balls is governed mainly by Newton’s three Laws of Tennis. These laws are fully explained in our book The Physics and Technology of Tennis. The following is a summary of a few topics of interest to give you a flavour of how physics relates to sport and to the real world of everyday objects.
1. The sweet spots of a racquet
A tennis racquet, like a baseball or cricket bat, has two sweet spots. If a ball impacts at either of these spots, the force transmitted to the hand is sufficiently small that the player is almost unaware that the impact has occured. If the ball impacts at a point well away from the sweet spots, the player will feel some jarring and vibration of the handle. One of the sweet spots is the vibration node, located near the centre of the strings. The other sweet spot is called the centre of percussion (COP). These and some other significant spots on a racquet are shown below.
Contrary to popular opinion, the two sweet spots do not coincide with the point at which the ball rebounds with maximum speed, nor do they define the spots where the force on the hand is zero. Forces on the hand arise from three independent motions of the handle, namely rotation, translation and vibration. The vibrational component is absent when a ball strikes the vibration node. The rotational component, arising from recoil of the racquet head, exerts a torque on the hand, causing it rotate about an axis through the wrist. As a result, a force is always exerted on the upper part of the hand, and a force in the opposite direction is always exerted on the lower part of the hand. The two forces are equal and opposite for an impact at the COP, with the result that there is then no net force on the hand or forearm. This means that there is no sudden jarring of the arm for an impact at the COP.
2. Vibration Nodes
The first two vibration modes of a freely suspended tennis racquet are shown below. A racquet behaves like a uniform beam in this respect, despite its round head, since the centre of mass of a racquet is near the centre of the racquet. The fundamental mode has a frequency of about 100 Hz for a relatively flexible frame or about 180 Hz for a stiff frame. One node is near the centre of the strings, and the other node is in the handle. It is easy to hear this vibration if you hold the handle lightly at the node in the handle, with the handle near your ear, then strike the frame or strings. The vibration node on the strings is easily located using this technique. If you hold the handle firmly, the frame vibrations (but not the string vibrations) are strongly damped.
The next mode, for a uniform beam, has a frequency 2.75 times the fundamental frequency. It is not excited with any significant amplitude since the impact duration, T, of the ball on the strings is about 5 ms. The frequency spectrum of this pulse, approximately a half sine waveform, peaks at zero frequency and is zero at f = 1.5/T = 300 Hz , close to the second mode frequency. The impact will still excite string vibrations at about 500 Hz since the strings are not as strongly damped as the frame.
A metal tube will vibrate nicely when struck with a metal rod, but it does not vibrate when struck with a tennis ball. How come? The impact duration, about 0.005 sec, is too long to excite any vibration with a period shorter than about 0.002 sec, especially if the tube is struck at the fundamental vibration node (its sweet spot).
SEE a racquet vibrate
The vibration of a racquet is usually too small to see by eye, but a cardboard racquet vibrates the same way and shows the vibration modes clearly (see photo below). The top end was vibrated back and forth by about 1 mm at a frequency of about 30 Hz. The nodes in the frame and in the two strings are easily seen. The photo on the left is with the vibration generator switched off.
HEAR a racquet vibrate
The vibration frequency of a racquet depends on the stiffness of the frame. This is one way of determining whether you are using a stiff or a flexible racquet. A stiff racquet vibrates at 180 Hz or more. A flexible racquet vibrates at 140 Hz or less. QuickTime sound files for a racquet held near the ear and tapped by finger or by a ball near the tip are attached for frequencies of 120, 140, 160, 180, 200 and 220 Hz. These sounds are too low in frequency to be heard properly using the internal speakers of a computer. You will hear only some metallic clicks when the racquet is struck. Internal speakers usually have almost no bass response. You will need to connect external speakers, with fresh batteries if they are battery operated.
FEEL a racquet vibrate
The best way to feel a racquet vibrate is to hit a ball on the tennis court. What is it that you “feel”? Does it feel good or bad? Why do different racquets feel different? Does a $400 racquet feel a lot better than a $100 racquet, and if so in what way does it feel better? These are not easy questions to answer. I have never heard a good explanation or description in terms of the physics of feel. Players say that some racquets feel more powerful than others, but how do they know unless they measure the ball speed, which they don’t?
Can you feel the difference between a 140 Hz vibration and a 160 Hz vibration? One way to test this is to put your hand on the speaker used to play the sound files. It will help to use an external speaker rather than the inbuilt speaker in your computer. You can feel a thump every time the racquet is hit but that’s because you can easily feel the change in amplitude (or size) of the vibration. I find that high frequencies tickle my hand more than low frequencies, especially if the soft part of the palm of my hand rests gently on the speaker.
3. Centre of Percussion
Consider a racquet that is freely suspended by a long length of string or balanced vertically on the end of its handle. If a ball impacts at the centre of mass (CM), the racquet will recoil at a speed V. All parts of the racquet will recoil at the same speed V. If the ball impacts at any other point on the strings, the racquet will recoil and it will also rotate about its CM. The whole racquet then moves away from the ball with a speed V1 due to the recoil , but the handle simultaneously moves towards the ball with speed V2 due to rotation of the racquet. If there is any point in the handle where V1 = V2, then that point will remain stationary and the rest of the racquet will rotate about that point as shown below.
The axis of rotation is called the conjugate point with respect to the impact point, and the impact point is called the centre of percussion (COP) for that particular axis of rotation. The axis and the COP form a pair of conjugate points. For an impact near the tip of the racquet, the axis of rotation is about half way between the end of the handle and the CM. For an impact near the throat of the racquet, the axis of rotation is beyond the end of the handle.
Now consider a racquet that is suspended by a rod passing through a hole drilled through the handle so that the racquet can rotate freely about this axis when a ball strikes the strings. When a ball impacts on the strings, the handle will exert a force on the axis unless the ball impacts at the COP. Consequently, the COP is regarded as a second sweet spot since the force on the hand should be zero for an impact at the COP. However, the hand extends over a reasonable length of the handle, and every point in the handle will have a different centre of percussion on the strings.
It seems that no matter where the ball strikes the strings, there may well be a point under the hand where the force is zero, but there will always be other points where the force is not zero. In fact, that is exactly what is measured. The impact causes the racquet head to recoil, so the whole racquet rotates in the hand, exerting a force on the upper part of the hand and a force in the opposite direction on the lower part of the hand. The torque causes the hand to rotate about an axis through the wrist. However, if the impact is at the COP for rotation about the end of the handle, then the force on the upper part of the hand is equal and opposite the force on the lower part of the hand, so there is no net force on the hand or the forearm. Therefore, the forearm will not receive a sudden jolt if the ball impacts at this COP.
The COP can be located approximately by holding the end of the handle between your finger and thumb and throwing a ball onto the strings. If the handle jumps out of your hand, then you missed the COP. It is usually located about 5 cm away from the centre of the strings. A more accurate measurement of the COP can be made with a piezo disk (extracted from a piezo buzzer) between the thumb and the handle to measure the force acting on the thumb.
4. The dead spot of a racquet
Clamp the end of the handle on a table, using your hand to press on the handle, so the rest of the racquet hangs over the edge of the table. Then drop a ball onto the strings at various points. The ball will bounce best near the throat. There is a spot near the tip where the ball doesn't bounce at all. That's the dead spot. At the dead spot, all of the energy of the ball is given to the racquet, and the racquet does not give any energy back to the ball. The reason is that the effective mass of the racquet at that point is equal to the mass of the ball. The effective mass is the ratio of the force at that point to the acceleration at that point (F = ma so m = F/a). If a ball of mass m collides head-on with another ball of mass m at rest, then the incident ball stops dead and gives all its energy to the other ball.
Similarly, if a moving racquet strikes a stationary ball at the dead spot, then all the rotational energy of the racquet is given to the ball. A good place to hit a ball when serving is near the dead spot. However, when returning a fast serve, the dead spot is the worst place to hit the ball. The best spot is nearer the throat of the racquet since that's where the ball bounces best.
5. Tennis balls
The rules of tennis specify that the ball must bounce to a height between 53 and 58 inches when dropped from a height of 100 inches onto a concrete slab. What happens in actual play is hard to predict, but a good test is to drop a ball onto the strings when the head is clamped (eg by placing the racquet on the floor and stepping on the handle near the head). When dropped from a height of say 1 metre, the ball will bounce to a height of about 0.70 metre. The ball loses about 45% of its energy when dropped on concrete, but it loses only 30% of its energy when dropped on the strings. That's because the strings absorb some of the impact energy and then give almost all of that back to the ball. The amount of energy lost by the ball depends on its compression. When dropped from 100 inches on concrete, it compresses by about 6 mm. When dropped on the strings, it compresses by about 3 mm. The bigger the compression, the more energy is lost when the ball expands back to its original shape. That means that at high impact speeds, where the ball compresses more, the energy loss is even greater. Furthermore, the fraction of the ball's energy that is lost also increases as the the ball's energy is increased or as the compression is increased.
6. Ball Spin
The modern game of tennis is dominated by the amount of spin that players can impart to the ball. The change from small 9 inch heads in wood racquets to large 10.5 inch heads in graphite racquets allowed players to hit with more topspin since the ball was less likely to clip the frame. This also allowed players to hit the ball harder since balls hit with topspin dive down more sharply onto the court after they clear the net. By hitting the ball harder, players generated even more topspin, which allowed them to hit the ball even harder. The modern game is played at a much faster pace than in the wood racquet era, not because modern racquets or players are more powerful but because racquet heads are now an inch or two wider, allowing players to hit the ball with much more topspin.
To extract as much topspin as possible from a stroke, players have learnt to swing up at the ball and to tilt the racquet head forward, That way, a ball coming off the court with topspin can be returned with topspin. The spin direction must be reversed to achieve this result. Two QuickTime movie files are attached showing how this is done, one by myself and one by Federer. The physics of each shot is the same, the only real difference being that Federer has a more elegant style. In my case, I filmed the shot at 25 frames/sec. The top half of the film is taken 10 ms before the bottom half so the magnitude and direction of spin could be measured more easily. The film of Federer was taken at about 1000 frames/sec judging by the fact that the ball sits on the strings for about 5ms and is seen for 4 or 5 frames on the strings.
7. PowerPoint Presentations and Movies
I often get requests from students wanting ideas for experiments or projects relating to the physics of tennis. I have prepared a few PowerPoint presentations on this subject, including some of the basic physics behind each experiment. They can be viewed directly on the web or downloaded as .ppt files. This page also contains some movies concerning various tennis experiments.
7. Further reading
Brody, H. (1979) Physics of the tennis racket. American Journal of Physics 47, 482-487.Brody, H. (1981) Physics of the tennis racket II: The sweet spot. American Journal of Physics, 49, 816-819.Brody, H. (1987) Tennis Science for Tennis Players, University of Pennsylvania Press.Brody, H. (1995) How would a physicist design a tennis racket?. Physics Today, 48, 26-31.
Howard Brody, Rod Cross and Crawford Lindsey, The Physics and Technology of Tennis (available from www.racquettech.com)
Rod Cross and Crawford Lindsey, Technical Tennis (also available from www.racquettech.com)
Rod Cross, Crawford Lindsey and Howard Brody at the TST2003 Tennis Conference organised by the International Tennis Federation in London.
Tuesday, June 17, 2008
Sunday, June 15, 2008
Selecting the Right Racquet
Selecting the Right Racquet
by Tennis Warehouse
If you’re like most Tennis Warehouse customers, you already have an idea of the type of racquet you’re seeking. You want to upgrade from your current racquet - maybe you’re seeking more power, more control, more comfort... or a little of all three. Whatever your reason(s) for purchasing a new racquet, you have some basis on which to make your decision.
Then again, you may not have a clue as to which racquet is best for you and are simply motivated by a review you read. Add to the confusion the shear amount of racquets available and choosing the right racquet becomes pretty daunting! To make this process a little easier, here’s a primer on racquet characteristics and how they affect performance. We also suggest you read our racquet reviews where you’ll find detailed information from real tennis players on how a specific racquet performs on-court. Our Racquet Technologies section includes explanations and illustrations of racquet technologies and materials, such as nCode, Hot Melt, Liquidmetal, and F.I.R.E., to name a few. Finally, our General Racquet & String Terms provide definitions of terms that are used throughout our website to describe racquet and string performance.
Today, there are 3 major racquet categories, with several subcategories.
They are:
Category 1: Power or Game Improvement Racquets
This is the term used by racquet manufacturers for power-oriented racquets. In most cases, these racquet models feature oversize to super-oversize heads (107-135 square inches), are lightweight (8-9.5 ounces), longer (27-29 inches) stiffer and are balanced head-heavy (or evenly balanced) to retain enough weight in the hitting zone. Designed for players with shorter, slower swings and who want more power from the racquet. Here are some of the top game improvement racquets:
Select Game Improvement Racquets
Babolat Drive Z 118 Racquets
A very comfortable and powerful racquet. The forgiving response makes this a great choice for beginning players looking for maximum pop on all their shots. Headsize: 118sq. inches. Strung weight: 9.9 ounces. Price: $229.00,
Dunlop Aerogel 9Hundred Racquets
Dunlop's most powerful Aerogel racquet. Provides a good combination of power and comfort in a 113 square inch head. 9.6 ounces. 27.5 inches long.Price: $189.00,
Customer Feedback,
Prince O3 Speedport Gold Racquets
Loaded with power and comfort features, this racquet is a solid choice for beginner to intermediate players seeking an emphasis on power and comfort. Headsize: 115sq. inches. Length: 27.5 inches.Price: $249.99,
Prince O3 Speedport Platinum Racquets
A powerful, comfortable racquet that also impresses with a maneuverable feel and easy access to spin. The very large sweetspot is ideal for beginners and those seeking lots of power. Headsize: 125sq. inches. Length: 27.5 inches.Price: $269.99,
Customer Feedback,
Prince O3 Speedport Silver Racquets
A powerful, comfortable, very maneuverable and spin friendly racquet. This one’s a must demo for 2.0-4.0 level players looking for some added zip. Length: 27.5. Headsize: 118sq. inches. String pattern: 16/19.Price: $239.99,
Customer Feedback,
Tecnifibre TFlash 270 OS Racquets
Tecnifibre now offers an oversize racquet to their TFlash line. A nice combination of forgiveness and playability. Strung weight: 10.3 ounces. Balance: 3 points head light.Price: $179.99, Customer Feedback,
Volkl DNX 1 Power Arm Racquets
Volkl's most powerful racquet - thanks to an all-new POWER ARM technology - offers a very comfortable response and is an ideal racquet for the beginner to 3.5 level player. Length 27.8 inches. Headsize: 115sq. inches. Strung weight: 9.1 ounces. Price: $299.99, Customer Feedback,
Wilson K Factor KOne Racquets
Offering unrivaled control in a power/game improvement stick, the KOne is a must demo. Impressive mobility, comfort and stability makes for an enjoyable hit for beginning to intermediate players. Headsize: 122sq. inches. Length: 27.5 inches.Price: $299.00, Customer Feedback,
Wilson K Factor KThree Racquets
Offering excellent comfort and mobility, this is a great choice for the 3.0+ level player. Impressive control and easy access to spin makes for fun hitting with the KThree. Head Size: 115 sq. inches. Length: 27.5 inches.Price: $269.00, Customer Feedback,
Wilson K Factor KZero Racquets
A great choice for beginners seeking a game improvement racquet. The KZero is the lightest racquet in the K Factor line. Impressive power and control. Super oversize head: 118 sq. in. Length: 27.5 inches. Price: $279.00, Customer Feedback,
Yonex RQS 55 Racquets
Powerful, light and easy to maneuver, this one is a great choice for players looking to add some zip to their shots. Racquet length: 27.5 inches. Headsize: 112 sq. inches.Price: $199.00, Customer Feedback,
Category 2:
‘Tweener Racquets
There are several models that offer a blend of features from game improvement and player’s racquets. They are often light-er (9.5-11 ounces), balanced anywhere from slightly head-light to slightly head-heavy, have midplus (95-102 square inches) heads and are usually extended length (27.5-28 inches). These racquet models offer low-medium to medium-high power and are most appealing to intermediate-advanced players, seeking enhanced maneuverability. Here are some of the top 'tweener racquets:
Select Tweener Racquets
Babolat Pure Drive Standard Cortex Racquets
Babolat's hugely popular Pure Drive gets updated with new Cortex technology. Offers the same great playability with more comfort and a solid feel.Price: $185.00, Review, Customer Feedback,
Becker Pro RacquetsA versatile racquet that offers impressive power and excellent access to spin for intermediate to advanced players. Maneuverable and comfortable, this racquet is ideal for today's topspin power hitting. Headsize: 100sq. inches. Standard length.Price: $185.00, Customer Feedback,
Becker V1 Oversize Racquets
This Oversize racquet offers some useful pop in a very mobile and spin friendly package. Headsize: 110sq. inches. Strung Weight: 10.8oz. Length: 27.6 inches.Price: $219.99, Customer Feedback,
Becker V1 Racquets
The Midplus offers some useful pop, mobility and spin for the intermediate player. Headsize: 102sq. inches. Strung Weight: 11 ounces. Length: 27 inches.Price: $219.99, Customer Feedback,
Dunlop Aerogel 5Hundred Racquets
This spin friendly racquet offers excellent access to spin, provides a crisp and clean response and plays with impressive comfort. Standard length. Headsize: 100sq. inches. String pattern: 16/18.Price: $159.00, Customer Feedback,
Head Metallix 4 Racquets
Light and maneuverable, this one also offers impressive stability and comfort. Offering good access to spin and some useful pop, this one is well suited to 3.5-4.5 level players. Headsize: 107sq. inches. Length: 27.3 inches. Strung Weight: 9.3 ounces.Price: $179.99, Customer Feedback,
Prince O3 Speedport Red Racquets
Very spin friendly, very maneuverable and very comfortable, this impressive racquet will appeal to a variety of player types from the 3.0 to 5.5 level. Length: 27.25. Headsize: 105sq. inches. String pattern: 16/19. Price: $199.99, Review, Customer Feedback,
Volkl DNX 8 Racquets
With some useful pop, easy access to spin, excellent maneuverability and a comfortable response, this racquet has broad appeal for players rated 3.5 and up. Headsize: 100 sq. in. Length: 27 inches. Strung Weight: 10.9 ounces. String Pattern: 16/18.Price: $169.99, Customer Feedback,
Wilson K Factor KFive 98 Mid+ Racquets
Impressive power and comfort are offered by this KFive MP. Headsize: 98 sq. in. Length: 27.25". Head heavy balance. Best suited to players at the 3.5+ level.Price: $219.00, Customer Feedback,
Wilson K Factor KFour 105 Mid+ Racquets
Wilson redefines the "4" with this impressive offering. A comfortable response is accompanied by easy access to spin and impressive maneuverability. Players at the 4.0+ level will find lots of performance here. Length: 27.25. Headsize: 105sq. inches. String pattern: 16/19.Price: $199.00, Customer Feedback,
Yonex RQS 11 Racquets
The RQS 11 offers a pleasing blend of power, control and maneuverability. A perfect choice for the 4.0+ shot maker who likes to mix pace, spin and placement. Headsize: 100 square inches. Length: 27.5 inches. Strung Weight: 10.4 ounces.Price: $179.00, Customer Feedback,
Category 3: Control or Player’s Racquets
Denotes racquets that would be used by professional and high-level club and college team players. These models are typically heavier in weight (11.5-13+ ounces), have smaller heads (85-98), thinner, more flexible beams and are balanced head light to retain maneuverability. The result is a low-power racquet, designed for players who provide their own power and prefer a racquet that offers more control. Can be standard or extended length. Here are some of top player's racquets:
Select Player's Racquets
Babolat Pure Storm Ltd. Racquets
A control oriented player's racquet that impresses with its feel and stability from all areas of the court. Best suited to 4.5+ level players who generate their own power. Standard length. Headsize: 95sq. inches.Price: $179.00,
Babolat Pure Storm Tour Racquets
A very solid and stable feeling player's racquet that comes loaded with feel and control. Replaces the Pure Control Team and is a solid, all court stick for 4.5+ level players. Headsize: 98sq. inches. Standard length.Price: $179.99, Review, Customer Feedback,
Becker 11 Racquets
Offering a very high level of feel and control for advanced players (4.5+), the Becker 11 provides a responsive feel akin to the classic Volkl player's racquets. Headsize: 98sq. inches. Strung Weight: 12 oz. String Pattern: 18/20.Price: $199.99, Review, Customer Feedback,
Dunlop Aerogel 1Hundred Racquets
A player's racquet that's loaded with feel and control. The open string pattern provides excellent spin potential, a lively feel and a healthy sweetspot. Headsize: 90sq. inches.Price: $149.00,
Dunlop Aerogel 2Hundred RacquetsAn excellent update to the 200 series, the Aerogel 2Hundred offers a high level of comfort, ball feel, stability and control to every shot. A solid choice for advanced level players. Headsize: 95sq. inches. Length: 27 inches. String pattern: 18/20. Weight: 12 oz.Price: $149.00, Review, Customer Feedback,
Fischer M Comp 95 Racquets
This stable and comfortable racquet offers the ultimate in control. Advanced players will find this one feels like an extension of their arm. One of Fischer's No Tolerance racquets, each unstrung racquet is built to an exact weight of 330 grams, guaranteed.Price: $199.99, Customer Feedback,
Head Flexpoint Prestige Midplus XL RacquetsThe Prestige offers an extended version in a midplus headsize. Plenty of classic Prestige heritage remains with some extra pop and stability. A must demo for Prestige fans and players seeking control, stability and the utmost racquet feedback.Price: $199.95, Review, Customer Feedback,
Head Flexpoint Prestige Racquets
The Prestige is available again in the midsize version. Plenty of classic Prestige heritage remains with some extra pop and stability. A must demo for Prestige fans and players seeking control, stability and the utmost racquet feedback.Price: $199.95, Review, Customer Feedback,
Kneissl Red Star Racquets
An impressive control oriented racquet that's well suited to all court players. Offers excellent feedback, a high level of control and excellent bite on slice shots. Length: 27.5 inches. Strung weight: 11.2 ounces. Swingweight: 327 (RDC).Price: $169.99, Customer Feedback,
Prince O3 Speedport Tour Racquets
Offering comfort and maneuverability in an advanced player's spec racquet, Prince allows you to fine tune the feel of this one with the Speedport Tuning System. Headsize: 97sq. inches. Strung weight: 11.7 ounces. Price: $199.99, Customer Feedback,
Tecnifibre TFight 335 (16x20) Racquets
This spin friendly version of the TFight 335 offers a livelier feel than its tighter string patterned brother and excellent comfort. Standard length. Headsize: 97 sq. inches. Strung weight: 12.4 ounces. Balance: 10 points head light.Price: $169.95, Customer Feedback,
Wilson K Factor KSix-One Tour 90 Racquets
Racquet choice of ATP #1 Roger Federer, the KSix-One Tour 90 is the most forgiving Tour 90 yet. Subtle updates to the frame design make this one a must hit for 5.0+ level players. Standard length. Strung weight: 12.5 ounces. Swingweight: 336 (RDC). Balance: 9pts head light.Price: $199.00, Review, Customer Feedback,
Yonex RDS 002 Tour RacquetsThis control oriented racquet offers great feel and stability. Maneuverability is enhanced via a head light balance and the stringbed offers excellent access to spin. Headsize: 98sq. inches. Strung weight: 12.1 ounces. Swingweight: 330 (RDC).Price: $179.00, Customer Feedback,
When making a racquet choice,you’ll need to consider the following features:
Head Size
Power is directly related to head size - a larger head will provide more power than a smaller head, all other things being equal. A larger head also offers a larger hitting area and sweetspot, providing more forgiveness on off-center hits. Today’s racquets are offered in head sizes ranging from 85 to 135 square inches, with the most common being 95-110. These head sizes offer a compromise between power and control for many players. Generally speaking, a smaller racquet head appeals to more accomplished players seeking more control, while larger racquets appeal to beginning and intermediate players seeking more power and a larger sweetspot.
Length
Racquets are available in lengths ranging from 27-29 inches, the legal limit for tournament play. Standard racquets are 27 inches long. A longer racquet provides more reach on groundstrokes, added leverage on serves and slightly more power overall than standard length racquets, all other things being equal. For most players, switching from a standard length racquet to one that is 1/2 -1 inch longer doesn’t normally present much of a problem. Most (but not all) longer racquets are lighter than their standard-length counterparts to keep them maneuverable. As racquet length increases, so does dynamic swingweight. Simply lengthening a 27 inch racquet without reducing weight would result in a very unwieldy “club”.
Weight & Balance
These two characteristics most influence how a racquet feels when you pick it up and when you swing it on the tennis court. Some basic concepts - a heavy racquet is more powerful, more stable and transmits less shock than a lighter racquet (all other things being equal). A lighter racquet is more maneuverable and thus, a player is able to swing it faster. If this is true, won’t a lighter racquet that is swung fast generate the same power as a heavier racquet that’s swung more slowly? This question has been hotly debated ever since Wilson introduced their Hammer racquets back in 1990. Until then, racquet weights averaged 12-13 ounces and were balanced head light (or handle heavy). Wilson’s Hammer “technology” reduced overall racquet weight (10-11 ounces) but distributed more mass in the head, resulting in a head-heavy balance. The idea was to improve maneuverability without sacrificing power by keeping weight in the racquet’s hitting zone. Since then, racquet weights have steadily dropped and now we have sub-10 ounce offerings from most manufacturers. Is lighter better? Not necessarily. Well then, which racquet weight is best for you? What about racquet balance? Is head-light, head-heavy or even balance best? In order to answer this question, you need a point of reference. How heavy is your current racquet? Is it head light or head-heavy? How much? If you don’t know, you can e-mail us at info@tennis-warehouse.com and we’ll send you the manufacturer’s specifications, if available.
Next, do you want a lighter, heavier or similarly weighted racquet? Head-light, head-heavy or evenly balanced? Chances are you don’t know what you want until you play with a racquet. If this isn’t feasible, here are some guidelines on the advantages and disadvantages of different weights and balances.
Heavier, head-light racquets- preferred by most professional players, these racquets are often referred to as being “traditionally weighted and balanced” racquets. They typically weigh 11-13 ounces and are balanced 1/2 to 1-1/2 inches head light in order to retain maneuverability. In most cases, these racquets are also referred to as “player’s” racquets because they are generally more control-oriented and designed for players who provide their own power.
Lightweight, head-heavy racquets - several years ago, Wilson discovered it was possible to make a racquet more maneuverable without reducing weight in the head. By removing weight in the handle, the racquet was lighter overall, while still retaining mass in the upper hoop, where ball contact occurs. This was the concept behind their Hammer and Sledge Hammer designs. Several other racquet manufacturers have subsequently introduced lightweight, head-heavy (and evenly balanced) racquets. The advantages of this racquet type are increased maneuverability without sacrificing power, especially on groundstrokes. The disadvantages are less clear - some “experts” argue that reducing weight increases the amount of shock transferred to the wrist, elbow and shoulder. Some players who have switched from traditionally weighted and balanced racquets to lightweight, head-heavy models claim the racquets don’t feel “solid”. Clearly, you can’t get something for nothing. Reducing racquet weight will alter its feel - for better or for worse. Keep in mind, you can always add weight to a racquet if it’s too light. Reducing racquet weight, however, is almost impossible.
Frame Stiffness
The amount a frame deflects during ball contact directly affects its power potential. A stiffer racquet bends less, thus depleting less energy from the ball. A flexible racquet bends more, resulting in more energy loss. A common myth among players is that a flexible racquet, that bends back more, returns more power to the ball due to a catapult-effect. The ball remains on the strings for 3-5 milliseconds, much shorter than it takes a frame to recover. Consequently, a racquet frame doesn’t “return” energy to the ball, it absorbs energy - either more or less, depending on stiffness. Stiffer racquets don’t deflect as much on impact, resulting in less power drain than a flexible racquet.
Frame stiffness doesn’t only affect power though. Control and comfort are also at stake. Generally speaking, a racquet that offers more power provides less control. However, this is largely dependent on player type and ability. An advanced player may prefer a flexible racquet because he or she has a long, fast swing and provides plenty of power. A stiff racquet might be too powerful for this player, resulting in too many balls landing long. A beginning or intermediate player though, may find a stiffer racquet that doesn’t deflect as much on impact, provides better control. This may also apply to a more advanced player with short, compact strokes. To a certain point, stiffer racquets are generally less comfortable than more flexible racquets. A very stiff frame will transmit more impact shock to the wrist, elbow and shoulder than a medium stiff frame. Comfort is difficult to measure - each player has a different perception of what feels comfortable. However, players with arm and/or shoulder problems will generally benefit more from a flexible to medium-stiff frame and should likely avoid stiff or very stiff frames. A lesser known effect of frame stiffness is the amount of spin that can be generated. Generally speaking, stiffer racquets provide less spin than flexible racquets because the ball leaves the stringbed more quickly.
String Pattern
Often overlooked by many recreational players, string pattern density influences many aspects of a racquet’s overall performance and feel. When we discuss string pattern density, we refer to open and dense (or closed).
An open string pattern will deflect more on impact than a denser pattern, providing greater ball rebound. Strung at the same tension (in similar racquets) an open string pattern won’t feel as “tight” as a dense string pattern. Open string patterns also allow for more spin potential, as the ball can embed itself into the strings more, due to their wider spacing. Players seeking more spin will benefit from a more open string pattern. The price one may pay for this, though, is reduced string durability. Open string patterns allow the strings to move more freely, increasing abrasion which causes string breakage.
A denser string pattern won’t deflect as much upon ball impact, resulting in less rebound energy. More closely spaced strings will also offer less spin potential but will last longer than a similar racquet featuring a more open string pattern. Players who don’t hit with much spin and are seeking enhanced control will generally prefer racquets with denser string patterns, as will hard-hitting topspin players seeking increased string durability.
Grip/Handle Systems
As racquets become lighter and lighter, manufacturers are seeking ways to improve comfort without significantly increasing weight. Incorporating a shock and vibration dampening system in the handle is the most common method currently being used. Dunlop’s ISIS, Head’s No SHOX, Prince’s Air and Volkl's’s Sensor handle systems offer varying degrees of effectiveness in reducing frame shock and vibration. Wilson and Yonex also offer comfort systems located in the racquet shaft such as Iso-Zorb and V-Con technologies.
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Toll Free in the U.S. 1-800-8-TENNIS U.S. Customer Email info@tennis-warehouse.comInternational Email twint@tennis-warehouse.com
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by Tennis Warehouse
If you’re like most Tennis Warehouse customers, you already have an idea of the type of racquet you’re seeking. You want to upgrade from your current racquet - maybe you’re seeking more power, more control, more comfort... or a little of all three. Whatever your reason(s) for purchasing a new racquet, you have some basis on which to make your decision.
Then again, you may not have a clue as to which racquet is best for you and are simply motivated by a review you read. Add to the confusion the shear amount of racquets available and choosing the right racquet becomes pretty daunting! To make this process a little easier, here’s a primer on racquet characteristics and how they affect performance. We also suggest you read our racquet reviews where you’ll find detailed information from real tennis players on how a specific racquet performs on-court. Our Racquet Technologies section includes explanations and illustrations of racquet technologies and materials, such as nCode, Hot Melt, Liquidmetal, and F.I.R.E., to name a few. Finally, our General Racquet & String Terms provide definitions of terms that are used throughout our website to describe racquet and string performance.
Today, there are 3 major racquet categories, with several subcategories.
They are:
Category 1: Power or Game Improvement Racquets
This is the term used by racquet manufacturers for power-oriented racquets. In most cases, these racquet models feature oversize to super-oversize heads (107-135 square inches), are lightweight (8-9.5 ounces), longer (27-29 inches) stiffer and are balanced head-heavy (or evenly balanced) to retain enough weight in the hitting zone. Designed for players with shorter, slower swings and who want more power from the racquet. Here are some of the top game improvement racquets:
Select Game Improvement Racquets
Babolat Drive Z 118 Racquets
A very comfortable and powerful racquet. The forgiving response makes this a great choice for beginning players looking for maximum pop on all their shots. Headsize: 118sq. inches. Strung weight: 9.9 ounces. Price: $229.00,
Dunlop Aerogel 9Hundred Racquets
Dunlop's most powerful Aerogel racquet. Provides a good combination of power and comfort in a 113 square inch head. 9.6 ounces. 27.5 inches long.Price: $189.00,
Customer Feedback,
Prince O3 Speedport Gold Racquets
Loaded with power and comfort features, this racquet is a solid choice for beginner to intermediate players seeking an emphasis on power and comfort. Headsize: 115sq. inches. Length: 27.5 inches.Price: $249.99,
Prince O3 Speedport Platinum Racquets
A powerful, comfortable racquet that also impresses with a maneuverable feel and easy access to spin. The very large sweetspot is ideal for beginners and those seeking lots of power. Headsize: 125sq. inches. Length: 27.5 inches.Price: $269.99,
Customer Feedback,
Prince O3 Speedport Silver Racquets
A powerful, comfortable, very maneuverable and spin friendly racquet. This one’s a must demo for 2.0-4.0 level players looking for some added zip. Length: 27.5. Headsize: 118sq. inches. String pattern: 16/19.Price: $239.99,
Customer Feedback,
Tecnifibre TFlash 270 OS Racquets
Tecnifibre now offers an oversize racquet to their TFlash line. A nice combination of forgiveness and playability. Strung weight: 10.3 ounces. Balance: 3 points head light.Price: $179.99, Customer Feedback,
Volkl DNX 1 Power Arm Racquets
Volkl's most powerful racquet - thanks to an all-new POWER ARM technology - offers a very comfortable response and is an ideal racquet for the beginner to 3.5 level player. Length 27.8 inches. Headsize: 115sq. inches. Strung weight: 9.1 ounces. Price: $299.99, Customer Feedback,
Wilson K Factor KOne Racquets
Offering unrivaled control in a power/game improvement stick, the KOne is a must demo. Impressive mobility, comfort and stability makes for an enjoyable hit for beginning to intermediate players. Headsize: 122sq. inches. Length: 27.5 inches.Price: $299.00, Customer Feedback,
Wilson K Factor KThree Racquets
Offering excellent comfort and mobility, this is a great choice for the 3.0+ level player. Impressive control and easy access to spin makes for fun hitting with the KThree. Head Size: 115 sq. inches. Length: 27.5 inches.Price: $269.00, Customer Feedback,
Wilson K Factor KZero Racquets
A great choice for beginners seeking a game improvement racquet. The KZero is the lightest racquet in the K Factor line. Impressive power and control. Super oversize head: 118 sq. in. Length: 27.5 inches. Price: $279.00, Customer Feedback,
Yonex RQS 55 Racquets
Powerful, light and easy to maneuver, this one is a great choice for players looking to add some zip to their shots. Racquet length: 27.5 inches. Headsize: 112 sq. inches.Price: $199.00, Customer Feedback,
Category 2:
‘Tweener Racquets
There are several models that offer a blend of features from game improvement and player’s racquets. They are often light-er (9.5-11 ounces), balanced anywhere from slightly head-light to slightly head-heavy, have midplus (95-102 square inches) heads and are usually extended length (27.5-28 inches). These racquet models offer low-medium to medium-high power and are most appealing to intermediate-advanced players, seeking enhanced maneuverability. Here are some of the top 'tweener racquets:
Select Tweener Racquets
Babolat Pure Drive Standard Cortex Racquets
Babolat's hugely popular Pure Drive gets updated with new Cortex technology. Offers the same great playability with more comfort and a solid feel.Price: $185.00, Review, Customer Feedback,
Becker Pro RacquetsA versatile racquet that offers impressive power and excellent access to spin for intermediate to advanced players. Maneuverable and comfortable, this racquet is ideal for today's topspin power hitting. Headsize: 100sq. inches. Standard length.Price: $185.00, Customer Feedback,
Becker V1 Oversize Racquets
This Oversize racquet offers some useful pop in a very mobile and spin friendly package. Headsize: 110sq. inches. Strung Weight: 10.8oz. Length: 27.6 inches.Price: $219.99, Customer Feedback,
Becker V1 Racquets
The Midplus offers some useful pop, mobility and spin for the intermediate player. Headsize: 102sq. inches. Strung Weight: 11 ounces. Length: 27 inches.Price: $219.99, Customer Feedback,
Dunlop Aerogel 5Hundred Racquets
This spin friendly racquet offers excellent access to spin, provides a crisp and clean response and plays with impressive comfort. Standard length. Headsize: 100sq. inches. String pattern: 16/18.Price: $159.00, Customer Feedback,
Head Metallix 4 Racquets
Light and maneuverable, this one also offers impressive stability and comfort. Offering good access to spin and some useful pop, this one is well suited to 3.5-4.5 level players. Headsize: 107sq. inches. Length: 27.3 inches. Strung Weight: 9.3 ounces.Price: $179.99, Customer Feedback,
Prince O3 Speedport Red Racquets
Very spin friendly, very maneuverable and very comfortable, this impressive racquet will appeal to a variety of player types from the 3.0 to 5.5 level. Length: 27.25. Headsize: 105sq. inches. String pattern: 16/19. Price: $199.99, Review, Customer Feedback,
Volkl DNX 8 Racquets
With some useful pop, easy access to spin, excellent maneuverability and a comfortable response, this racquet has broad appeal for players rated 3.5 and up. Headsize: 100 sq. in. Length: 27 inches. Strung Weight: 10.9 ounces. String Pattern: 16/18.Price: $169.99, Customer Feedback,
Wilson K Factor KFive 98 Mid+ Racquets
Impressive power and comfort are offered by this KFive MP. Headsize: 98 sq. in. Length: 27.25". Head heavy balance. Best suited to players at the 3.5+ level.Price: $219.00, Customer Feedback,
Wilson K Factor KFour 105 Mid+ Racquets
Wilson redefines the "4" with this impressive offering. A comfortable response is accompanied by easy access to spin and impressive maneuverability. Players at the 4.0+ level will find lots of performance here. Length: 27.25. Headsize: 105sq. inches. String pattern: 16/19.Price: $199.00, Customer Feedback,
Yonex RQS 11 Racquets
The RQS 11 offers a pleasing blend of power, control and maneuverability. A perfect choice for the 4.0+ shot maker who likes to mix pace, spin and placement. Headsize: 100 square inches. Length: 27.5 inches. Strung Weight: 10.4 ounces.Price: $179.00, Customer Feedback,
Category 3: Control or Player’s Racquets
Denotes racquets that would be used by professional and high-level club and college team players. These models are typically heavier in weight (11.5-13+ ounces), have smaller heads (85-98), thinner, more flexible beams and are balanced head light to retain maneuverability. The result is a low-power racquet, designed for players who provide their own power and prefer a racquet that offers more control. Can be standard or extended length. Here are some of top player's racquets:
Select Player's Racquets
Babolat Pure Storm Ltd. Racquets
A control oriented player's racquet that impresses with its feel and stability from all areas of the court. Best suited to 4.5+ level players who generate their own power. Standard length. Headsize: 95sq. inches.Price: $179.00,
Babolat Pure Storm Tour Racquets
A very solid and stable feeling player's racquet that comes loaded with feel and control. Replaces the Pure Control Team and is a solid, all court stick for 4.5+ level players. Headsize: 98sq. inches. Standard length.Price: $179.99, Review, Customer Feedback,
Becker 11 Racquets
Offering a very high level of feel and control for advanced players (4.5+), the Becker 11 provides a responsive feel akin to the classic Volkl player's racquets. Headsize: 98sq. inches. Strung Weight: 12 oz. String Pattern: 18/20.Price: $199.99, Review, Customer Feedback,
Dunlop Aerogel 1Hundred Racquets
A player's racquet that's loaded with feel and control. The open string pattern provides excellent spin potential, a lively feel and a healthy sweetspot. Headsize: 90sq. inches.Price: $149.00,
Dunlop Aerogel 2Hundred RacquetsAn excellent update to the 200 series, the Aerogel 2Hundred offers a high level of comfort, ball feel, stability and control to every shot. A solid choice for advanced level players. Headsize: 95sq. inches. Length: 27 inches. String pattern: 18/20. Weight: 12 oz.Price: $149.00, Review, Customer Feedback,
Fischer M Comp 95 Racquets
This stable and comfortable racquet offers the ultimate in control. Advanced players will find this one feels like an extension of their arm. One of Fischer's No Tolerance racquets, each unstrung racquet is built to an exact weight of 330 grams, guaranteed.Price: $199.99, Customer Feedback,
Head Flexpoint Prestige Midplus XL RacquetsThe Prestige offers an extended version in a midplus headsize. Plenty of classic Prestige heritage remains with some extra pop and stability. A must demo for Prestige fans and players seeking control, stability and the utmost racquet feedback.Price: $199.95, Review, Customer Feedback,
Head Flexpoint Prestige Racquets
The Prestige is available again in the midsize version. Plenty of classic Prestige heritage remains with some extra pop and stability. A must demo for Prestige fans and players seeking control, stability and the utmost racquet feedback.Price: $199.95, Review, Customer Feedback,
Kneissl Red Star Racquets
An impressive control oriented racquet that's well suited to all court players. Offers excellent feedback, a high level of control and excellent bite on slice shots. Length: 27.5 inches. Strung weight: 11.2 ounces. Swingweight: 327 (RDC).Price: $169.99, Customer Feedback,
Prince O3 Speedport Tour Racquets
Offering comfort and maneuverability in an advanced player's spec racquet, Prince allows you to fine tune the feel of this one with the Speedport Tuning System. Headsize: 97sq. inches. Strung weight: 11.7 ounces. Price: $199.99, Customer Feedback,
Tecnifibre TFight 335 (16x20) Racquets
This spin friendly version of the TFight 335 offers a livelier feel than its tighter string patterned brother and excellent comfort. Standard length. Headsize: 97 sq. inches. Strung weight: 12.4 ounces. Balance: 10 points head light.Price: $169.95, Customer Feedback,
Wilson K Factor KSix-One Tour 90 Racquets
Racquet choice of ATP #1 Roger Federer, the KSix-One Tour 90 is the most forgiving Tour 90 yet. Subtle updates to the frame design make this one a must hit for 5.0+ level players. Standard length. Strung weight: 12.5 ounces. Swingweight: 336 (RDC). Balance: 9pts head light.Price: $199.00, Review, Customer Feedback,
Yonex RDS 002 Tour RacquetsThis control oriented racquet offers great feel and stability. Maneuverability is enhanced via a head light balance and the stringbed offers excellent access to spin. Headsize: 98sq. inches. Strung weight: 12.1 ounces. Swingweight: 330 (RDC).Price: $179.00, Customer Feedback,
When making a racquet choice,you’ll need to consider the following features:
Head Size
Power is directly related to head size - a larger head will provide more power than a smaller head, all other things being equal. A larger head also offers a larger hitting area and sweetspot, providing more forgiveness on off-center hits. Today’s racquets are offered in head sizes ranging from 85 to 135 square inches, with the most common being 95-110. These head sizes offer a compromise between power and control for many players. Generally speaking, a smaller racquet head appeals to more accomplished players seeking more control, while larger racquets appeal to beginning and intermediate players seeking more power and a larger sweetspot.
Length
Racquets are available in lengths ranging from 27-29 inches, the legal limit for tournament play. Standard racquets are 27 inches long. A longer racquet provides more reach on groundstrokes, added leverage on serves and slightly more power overall than standard length racquets, all other things being equal. For most players, switching from a standard length racquet to one that is 1/2 -1 inch longer doesn’t normally present much of a problem. Most (but not all) longer racquets are lighter than their standard-length counterparts to keep them maneuverable. As racquet length increases, so does dynamic swingweight. Simply lengthening a 27 inch racquet without reducing weight would result in a very unwieldy “club”.
Weight & Balance
These two characteristics most influence how a racquet feels when you pick it up and when you swing it on the tennis court. Some basic concepts - a heavy racquet is more powerful, more stable and transmits less shock than a lighter racquet (all other things being equal). A lighter racquet is more maneuverable and thus, a player is able to swing it faster. If this is true, won’t a lighter racquet that is swung fast generate the same power as a heavier racquet that’s swung more slowly? This question has been hotly debated ever since Wilson introduced their Hammer racquets back in 1990. Until then, racquet weights averaged 12-13 ounces and were balanced head light (or handle heavy). Wilson’s Hammer “technology” reduced overall racquet weight (10-11 ounces) but distributed more mass in the head, resulting in a head-heavy balance. The idea was to improve maneuverability without sacrificing power by keeping weight in the racquet’s hitting zone. Since then, racquet weights have steadily dropped and now we have sub-10 ounce offerings from most manufacturers. Is lighter better? Not necessarily. Well then, which racquet weight is best for you? What about racquet balance? Is head-light, head-heavy or even balance best? In order to answer this question, you need a point of reference. How heavy is your current racquet? Is it head light or head-heavy? How much? If you don’t know, you can e-mail us at info@tennis-warehouse.com and we’ll send you the manufacturer’s specifications, if available.
Next, do you want a lighter, heavier or similarly weighted racquet? Head-light, head-heavy or evenly balanced? Chances are you don’t know what you want until you play with a racquet. If this isn’t feasible, here are some guidelines on the advantages and disadvantages of different weights and balances.
Heavier, head-light racquets- preferred by most professional players, these racquets are often referred to as being “traditionally weighted and balanced” racquets. They typically weigh 11-13 ounces and are balanced 1/2 to 1-1/2 inches head light in order to retain maneuverability. In most cases, these racquets are also referred to as “player’s” racquets because they are generally more control-oriented and designed for players who provide their own power.
Lightweight, head-heavy racquets - several years ago, Wilson discovered it was possible to make a racquet more maneuverable without reducing weight in the head. By removing weight in the handle, the racquet was lighter overall, while still retaining mass in the upper hoop, where ball contact occurs. This was the concept behind their Hammer and Sledge Hammer designs. Several other racquet manufacturers have subsequently introduced lightweight, head-heavy (and evenly balanced) racquets. The advantages of this racquet type are increased maneuverability without sacrificing power, especially on groundstrokes. The disadvantages are less clear - some “experts” argue that reducing weight increases the amount of shock transferred to the wrist, elbow and shoulder. Some players who have switched from traditionally weighted and balanced racquets to lightweight, head-heavy models claim the racquets don’t feel “solid”. Clearly, you can’t get something for nothing. Reducing racquet weight will alter its feel - for better or for worse. Keep in mind, you can always add weight to a racquet if it’s too light. Reducing racquet weight, however, is almost impossible.
Frame Stiffness
The amount a frame deflects during ball contact directly affects its power potential. A stiffer racquet bends less, thus depleting less energy from the ball. A flexible racquet bends more, resulting in more energy loss. A common myth among players is that a flexible racquet, that bends back more, returns more power to the ball due to a catapult-effect. The ball remains on the strings for 3-5 milliseconds, much shorter than it takes a frame to recover. Consequently, a racquet frame doesn’t “return” energy to the ball, it absorbs energy - either more or less, depending on stiffness. Stiffer racquets don’t deflect as much on impact, resulting in less power drain than a flexible racquet.
Frame stiffness doesn’t only affect power though. Control and comfort are also at stake. Generally speaking, a racquet that offers more power provides less control. However, this is largely dependent on player type and ability. An advanced player may prefer a flexible racquet because he or she has a long, fast swing and provides plenty of power. A stiff racquet might be too powerful for this player, resulting in too many balls landing long. A beginning or intermediate player though, may find a stiffer racquet that doesn’t deflect as much on impact, provides better control. This may also apply to a more advanced player with short, compact strokes. To a certain point, stiffer racquets are generally less comfortable than more flexible racquets. A very stiff frame will transmit more impact shock to the wrist, elbow and shoulder than a medium stiff frame. Comfort is difficult to measure - each player has a different perception of what feels comfortable. However, players with arm and/or shoulder problems will generally benefit more from a flexible to medium-stiff frame and should likely avoid stiff or very stiff frames. A lesser known effect of frame stiffness is the amount of spin that can be generated. Generally speaking, stiffer racquets provide less spin than flexible racquets because the ball leaves the stringbed more quickly.
String Pattern
Often overlooked by many recreational players, string pattern density influences many aspects of a racquet’s overall performance and feel. When we discuss string pattern density, we refer to open and dense (or closed).
An open string pattern will deflect more on impact than a denser pattern, providing greater ball rebound. Strung at the same tension (in similar racquets) an open string pattern won’t feel as “tight” as a dense string pattern. Open string patterns also allow for more spin potential, as the ball can embed itself into the strings more, due to their wider spacing. Players seeking more spin will benefit from a more open string pattern. The price one may pay for this, though, is reduced string durability. Open string patterns allow the strings to move more freely, increasing abrasion which causes string breakage.
A denser string pattern won’t deflect as much upon ball impact, resulting in less rebound energy. More closely spaced strings will also offer less spin potential but will last longer than a similar racquet featuring a more open string pattern. Players who don’t hit with much spin and are seeking enhanced control will generally prefer racquets with denser string patterns, as will hard-hitting topspin players seeking increased string durability.
Grip/Handle Systems
As racquets become lighter and lighter, manufacturers are seeking ways to improve comfort without significantly increasing weight. Incorporating a shock and vibration dampening system in the handle is the most common method currently being used. Dunlop’s ISIS, Head’s No SHOX, Prince’s Air and Volkl's’s Sensor handle systems offer varying degrees of effectiveness in reducing frame shock and vibration. Wilson and Yonex also offer comfort systems located in the racquet shaft such as Iso-Zorb and V-Con technologies.
returnto home
Toll Free in the U.S. 1-800-8-TENNIS U.S. Customer Email info@tennis-warehouse.comInternational Email twint@tennis-warehouse.com
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