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Smart Tennis Strings
Background on the Tennis Strings Contributions to the Tennis Stroke:
- Tennis stroke: consists of 1) the human contribution, and 2) the tennis racket contribution.
- Human contribution: consists of the coordination of vision with; 1) feet, leg, hip and back body movement, 2) shoulder, elbow and arm movement, 3) wrist movement, and 4) hand and finger movement, 3) it essentially requires using all the parts of the body working in coordination to effectively play the tennis game.
- Tennis racket contribution: consists of 1) the racket size and shape which may vary but the overall maximum size is specified and limited by the Tennis Association Specification, 2) the material racket is made of, 3) the size (diameter and length) of the grip and the material of the grip wrap, 4) the tennis strings.
- Tennis strings contribution: consists of 1) material and diameter (16 gauge or 1.29 mm diameter is the general standard but it varies) of the tennis strings, 2) the tension that the tennis strings are strung too (typically between 45 and 80 lbs but between 55 and 75 lbs is more common), 3) the roughness or smoothness of the surface on the tennis string, and 3) the skill of the racket stringer and the resulting quality of the racket stringing (a human contribution) of the tennis strings; 4) thus, tennis strings are only one factor in having a good tennis stroke but is an important factor.
- Coefficient of friction and angle when ball bounces from tennis strings of racket: 1) when the ball impacts on the tennis strings of the racket, the rebound ball angle depends on, a) the angle difference between the ball incoming direction and the combined tilt of the forward moving racket direction plus the tilt of the tennis strings of the racket (if any), b) whether the ball is hit in the sweet spot of the tennis strings, and c) the coefficient of friction between the ball and the tennis strings, 2) if the tennis strings have a high degree of surface roughness the coefficient of friction will be higher and the rebound angle and resulting ball spin will be higher, 3) thus rough surface tennis strings can produce better ball spin, if that is desirable, compared to smooth surface tennis strings.
- The sweet spot of the racket and tennis strings: 1) the sweet spot of the racket and tennis strings is that part of the tennis strings where the smallest uniform tennis string squares are located, 2) the center of the sweet spot is located at the center of the axis along the grip in one dimension and typically approximately 1/4th to 1/3rd down from the top of the string portion of the racket in the axis of the top-to-bottom dimension, 3) the sweet spot is typically about 3 inches wide centered on the grip axis and 4 inches high centered on center sweet spot of the long portion of the racket, 4) a tennis player should always try to hit the tennis ball within the sweet spot area, 5) hitting the ball outside of the sweet spot area but even still having a parallel racket swing and approach to the ball , causes more string tension on the long side of a string than the short side and causes the tennis ball to come off of the tennis strings at an angle; this is further accentuated for tennis strings with a high coefficient of friction.
- Energy loss in a tennis string on stroke impact – a non-factor: The energy loss on stroke impact for any of the commonly available tennis strings is too small to make any significant difference between the different tennis string types even after many impacts, and is not a factor in choosing a tennis string type.
Details on Tennis Strings:
- Materials for tennis strings: Almost all tennis strings are made from one of the 4 materials of; 1) gut, 2) nylon, 3) polyester or 4) kevlar.
- General properties of the 4 tennis string materials:
- Gut: 1) is a highly elastic material, and 2) generally maintains better tension over time than the other tennis string materials, 3) it is the worst of the 4 tennis string materials in dynamic stiffness.
- Nylon: 1) it is the most common type of tennis string on the market, 2) it in general is almost as good as gut in maintaining tension over time, 3) its is available in many forms namely; a) it can be constructed from a solid core, or b) it can contains many small diameter filaments, or c) it can contain other composite materials or resins, or d) it can have a coating over the tennis string, 4) it is second worst of 4 in dynamic stiffness, and 5) however, the different forms of construction for nylon account for only a small difference in performance and overall it’s performance is distinctively different than the other 3 materials.
- Polyester: 1) is a relatively stiff tennis string compared to gut and nylon and some players prefer it since the impact duration is shorter and hence there is better ball control, 3) a large percentage of professional tennis players prefer and use polyester tennis strings, 4) however, it losses tension relatively quickly over time and must be restrung much more often than gut or nylon in order to maintain performance, 5) it is the best along with kevlar of the 4 in dynamic stiffness.
- Kevlar: 1) like polyester, it is also a relatively stiff string compared to gut and nylon and hence there is better ball control, 2) however, like polyester, it losses tension relatively quickly over time and must be restrung more often than gut or nylon in order to maintain performance, 3) it is the best along with polyester of the 4 in dynamic stiffness.
- Number of tennis strings on the market: 1) there are several hundred tennis strings available on the market, 2) unfortunately there are no standard tests or rules standards set up by a Tennis Association Governing Body on the properties of tennis strings, 3) as a result tennis strings can be as; a) thick or thin, b) rough or smooth, c) stiff or elastic, and d) made of whatever material that a manufacturer wishes to make them.
- Validity of tennis string manufacturers claims; 1) nearly all manufacturers rate their tennis strings with playability and performance ratings of essentially 10 out of 10 in capability, 2) however, there are no approved standards for testing tennis strings and as a result such manufacturer’s claims are not scientifically measurable or measured and are essentially worthless in trying to pick a best tennis string for one’s self.
- Measurable properties of tennis strings include: 1) elongation as a function of tennis string tension, 2) dynamic stiffness of tennis string, 3) loss in tension as a function of time and as a result of repeated impacts on the tennis string, 4) energy loss during an impact, and 5) the coefficient of friction between the tennis string and the outside cloth of the tennis ball.
- Major tennis strings manufacturers; include in alphabetical order, 1) Alpha, 2) Ashaway, 3) Babolat, 4) Bow Brand, 5) Forten, 6) Gamma, 7) Gosen, 8) Head, 9) Klip, 10) Prince, 11) Tecnifibre, 12) Velociti, 13) Wilson, and 14) Yonex.
- Environmental exposure of racket and tennis strings: 1) temperature, humidity, shock, vibration, bending forces and chemical exposure are examples of environment exposures to the racket and tennis strings, 2) such environmentally extreme exposures can either ruin or accelerate the degradation of the performance of the racket and tennis strings and cause the necessity for the early replacement and restringing of the tennis strings, and even an earlier than normal replacement of the tennis racket itself.
- Some means to prevent or reduce extreme environmental exposure of the racket and tennis strings: 1) when on or near the tennis court and not playing, take you racket out of the exposure to direct sun light, 2) never hit your racket on the ground or anything else, or throw it, as some people do in anger while playing tennis, 3) don’t keep your racket in your car except while driving to and from playing tennis and at such times keep it out of the exposure to direct sun light, 4) store racket when not playing tennis in a place that would be temperature comfortable to human beings and out of the sun light, such as a closet in the house, 5) never pile anything on top of the tennis racket or lean anything against it, 6) never expose the racket and tennis strings to chemicals such as even ant spray, cleaning fluids or the like, 6) periodically and when needed wipe your racket and tennis strings clean and wash with water if needed.
Picking the Best Tennis Strings and Tennis String Settings for Yourself:
- There are 3 things to pick with the tennis strings:
- Tennis strings material and the particular manufacturer and string.
- The tension that the tennis strings are strung to.
- The particular person or organization that will string your racket.
- There is no one best tennis string or tennis settings applicable to everyone and to everyone’s tennis game.
- Observations on tennis playing professionals: 1) they almost always own and keep with them many tennis rackets and deal with the same tennis stings stringer all the time; the cost to them in doing so is usually only a very minor consideration, 2) they usually have their rackets re-strung after each tennis tournament they play in and certainly before a major tournament, 3) thus, they have the luxury and can afford to experiment with using different tennis strings and/or tension settings on multiple rackets of the same racket type and at the same time, in order to determine which tennis string and which tension of the tennis strings best works for them, and this is a necessity to keep their tennis game at the top of its possible level, since it could be the difference in winning or losing a tournament, 4) thus also, they can consider polyester and kevlar tennis strings materials since their rackets are virtually always restrung within the relatively fast noticeable tension decline of these types of tennis strings (typically in a 1 to 3 month period if not significantly exposed to extreme environmental conditions or otherwise a shorter period).
- Observations on week end and amateur tennis players: 1) both the cost and the inconvenience of having a tennis racket restrung is almost always of major consideration 2) thus, polyester and kevlar are almost always not considered for the tennis strings because of the necessity to restring often because of their relatively rapid loss in tennis strings tension, 3) and thus, gut and nylon are the overwhelming choice for week end and amateur players and nylon significantly over gut, primarily because of the greater variations in the tennis strings and thus, in general a better possible adjustment to a persons tennis game, 4) gut and nylon have tennis strings replacement periods of typically one year and more, before the tension on the tennis strings becomes significantly reduced and of course only if the racket and tennis strings have not been exposed to extreme environmental conditions which will lesson this time.
- So, what should the week end and amateur tennis player do for the 3 actions in selecting tennis strings: 1) talk to your tennis playing friends and particularly those that have a similar power stroke, and ask them what kind of strings they have and the tension strung at - if they know, 2) talk to one but preferable more stringers of tennis strings, tell them about your game and ask them for their advice for your tennis strings, 3) pick a stringer and know the price for stringing but check out the tennis stringing equipment being used and be sure that it is not too old or worn out (you may want to check the price with other stringers just to be sure that you are not being ripped off), 4) as a result of this and also based on your experience with the strings that you are replacing, pick a tennis strings material and type; and if top spin is important to your game, pick a tennis string with a rough outside circumference, 5) pick a tennis strings stringing tension – typically in the low 70 lb range for strong stroke players, the high 50 or low 60 lb range for weaker stroke players and in between for in between stroke players, or if you were happy with what you had and know the tension level, just keep that or perhaps tweak what you had a little bit, 6) you are done and good luck in your tennis game with your new tennis strings.
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