History



Please find below a brief history of the changes that have been made to the rules and regulations regarding ball specifications.

1965 - 1966 - 1967 - 1969 - 1972 - 1974 - 1978 - 1981 - 1989 - 1996 - 1997 - 1998 - 1999 - 2000 - 2001 - 2002 - 2003 - 2004 - 2006 - 2008 - 2009 - 2010


1965 - Wording of the Rule

The ball shall have a uniform outer surface. If there are any seams they shall be stitchless. The ball shall be more than two and a half inches and less than two and five-eighths inches in diameter, and more than two ounces and less than two and one-sixteenth ounces in weight. The ball shall have a bound of more than 53 inches and less than 58 inches when dropped 100 inches upon a concrete base, and a deformation of more than .265 of an inch and less than .290 of an inch when subjected to a pressure of 18 lb. Applied to each end of any diameter. All tests for bound, size and deformation shall be made in accordance with the Regulations in the Appendix hereto.

APPENDIX: REGULATIONS FOR MAKING TESTS SPECIFIED IN RULE 3.

(i) Unless otherwise specified all tests shall be made at a temperature of approximately 68° Fahrenheit and any ball tested shall be at that temperature throughout when the test is commenced.

(ii) Unless otherwise specified the limits are for a test conducted in an atmospheric pressure resulting in a barometric reading of approximately 29.95 inches.

(iii) Other climatic standards may be fixed for localities where the average temperature and/or average barometric pressure at which the game is being played differ materially from 68° Fahrenheit and 29.95 inches respectively.

Applications for such adjusted standards may be made by any National Association to the International Lawn Tennis Federation and if approved shall be adopted for such localities. A table of such adjusted standards shall be added to the Appendix from time to time as they may be adopted.

(iv) In all tests for diameter a ring gauge shall be used, consisting of a metal plate, preferably non-corrosive, of a uniform thickness of one-eighth of an inch, in which there are two circular openings 2.575 inches and 2.675 inches in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of one-sixteenth of an inch. The ball shall not drop through the smaller opening by its own weight and shall drop through the larger opening by its own weight.

(v) In all tests for deformation conducted under Rule 3, the machine designed by Percy Herbert Stevens and patented in Great Britain under Patent No 230250, together with the subsequent additions and improvements thereto, shall be employed or such other machine which is approved by a National Association and gives equivalent readings to the Stevens machine.

(vi) Immediately before any ball is tested, it shall be dropped four times from a height of one hundred inches on to a concrete base.

(vii) To ascertain the deformation of any ball, three readings shall be taken, one each of three diameters at right angles to one another, so chosen that initially neither platen of the machine shall be in contact with any part of the cover seam. The average of these three readings shall be the deformation reading.

(viii) After the ball has been placed in position, the contact weight applied, the beam brought to the pointer level, the pointers set at zero, and the test weight placed on the beam, the pressure shall then be applied to the ball by turning the hand wheel at a uniform speed, and exactly five seconds shall elapse from the instant the beam leaves its seat until it is brought to the pointer level, whereupon the turning shall cease and the reading shall be taken.

APPENDIX B

For experimental purposes until 6th July, 1966, the following version of Rule 3 may be used:

Rule 3 (experimental).-The ball shall have a uniform outer surface. If there are any seams they shall be stitchless. The ball shall be more than two and a half inches and less than two and five-eighths inches in diameter, and more than two ounces and less than two and one-sixteenth ounces in weight. The ball shall have a bound of more than 53 inches and less than 58 inches when dropped 100 inches upon a concrete base, and a recovery deformation of more than .365 of an inch and less than .425 of an inch at 18lb. load. All tests for bound, size and deformation shall be made in accordance with the Regulations in the Appendix hereto.

Appendix (experimental) Sections (i) to (vi) as on previous page.

(vii) To ascertain the recovery deformation of any ball, three readings shall be taken, one each of three diameters at right angles to one another, so chosen that initially neither platen of the machine shall be in contact with any part of the cover seam. Every reading should be within the limits laid down.

(viii) Recovery deformation: After the ball has been placed in position and the beam brought to the pointer level the pointers are set at zero and the ball is deformed by one inch by turning the hand wheel at a uniform speed until 10 is reached on the wheel scale. After applying the weight equivalent to an 18lb. load the pressure is then released until the beam pointers are once again at zero, and the reading of the machine is taken after not less than 20 seconds.

Justification for the amendment

The Committee support the proposal that the period for experiment be extended for a further year. They understand that these proposals for amendment of the Rules are put forward mainly with the view to making the tests more comprehensive.

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1966 - Wording of the Rule 

Appendix B & Appendix (Experimental) amended

APPENDIX B

For experimental purposes from 6th July, 1966, until further notice, the following version of Rule 3 may be used:Rule 3 (experimental). The ball shall have a uniform outer surface and shall be white in colour. If there are any seams they shall be stitchless. The ball shall be more than two and a half inches (6.350 cm) and less than two and five-eighths inches (6.668 cm) in diameter, and more than two ounces (56.70 grams) and less than two and one-sixteenth ounces (58.47 grams) in weight. The ball shall have a bound of more than 53 inches (134.6 cm) and less than 58 inches (147.3 cm) when dropped 100 inches (254.0 cm) upon a concrete base. The ball shall have a forward deformation of more than .230 of an inch (.584 cm) and less than .290 of an inch (.737 cm) and a return deformation of more than .355 of an inch (.902 cm) and less than .425 of an inch (1.080 cm) at 18lb. (8.165kg) load. The two deformation figures shall be the averages of the three individual readings along three axes of the ball and no two individual readings shall differ by more than .030 of an inch (.076 cm) in each case. All tests for bound, size and deformation shall be made in accordance with the Regulations in the Appendix hereto. APPENDIX (EXPERIMENTAL) REGULATIONS FOR MAKING TESTS SPECIFIED IN RULE 3 (EXPERIMENTAL)

(i) Unless otherwise specified all tests shall be made at a temperature of approximately 68° Fahrenheit (20° Centigrade) and a relative humidity of approximately 60%. All balls should be removed from their container and kept at the recognised temperature and humidity for 24 hours prior to testing and shall be at that temperature and humidity when the test is commenced.

(ii) Unless otherwise specified the limits are for a test conducted in an atmospheric pressure resulting in a barometric reading of approximately 30 inches (76.2 cm).

(iii) Other standards may be fixed for localities where the average temperature, humidity or average barometric pressure at which the game is being played differ materially from 68° Fahrenheit (20° Centigrade), 60% and 30 inches (76.2 cm) respectively. Applications for such adjusted standards may be made by any National Association to the International Lawn Tennis Federation and if approved shall be adopted for such localities.

(iv) In all tests for diameter a ring gauge shall be used, consisting of a metal plate, preferably non-corrosive, of a uniform thickness of one-eighth of an inch (.318 cm), in which there are two circular openings 2.575 inches (6.541 cm) and 2.700 inches (6.858 cm) in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of one-sixteenth of an inch (.159 cm). The ball shall not drop through the smaller opening by its own weight and shall drop through the larger opening by its own weight.

(v) In all tests for deformation conducted under Rule 3, the machine designed by Percy Herbert Stevens and patented in Great Britain under Patent No. 230250, together with the subsequent additions and improvements thereto, including the modifications required to take return deformations shall be employed or such other machine which is approved by a National Association and gives equivalent readings to the Stevens machine.

(vi) Procedure for carrying out tests: (a) Pre-compression. Before any ball is tested it shall be steadily compressed by approximately one inch (2.54 cm), on each of three diameters at right angles to one another in succession; this process to be carried out three times (nine compressions in all). All tests to be completed within two hours of pre-compression. (b) Bound test (as in Rule 3). Measurements are to be taken from the concrete base to the bottom of the ball. (c) Size test (as in paragraph (iv) above). (d) Weight test (as in Rule 3). (e) Deformation test. The ball is placed in position on the modified Stevens machine so that neither platen of the machine is in contact with the cover seam. The contact weight is applied, the pointer and the mark brought level, and the dials set to zero. The test weight equivalent to 18lbs. (8.165kg) is placed on the beam and pressure applied by turning the wheel at a uniform speed so that five seconds elapse from the instant the beam leaves its seat until the pointer is brought level with the mark. When turning ceases the reading is recorded (forward deformation). The wheel is turned again until figure ten is reached on the wheel scale (one inch (2.54 cm) deformation). The wheel is then rotated in the opposite direction at a uniform speed (thus releasing pressure) until the beam pointer again coincides with the mark. After waiting ten seconds the pointer is adjusted to the mark if necessary. The reading is then recorded (return deformation). This procedure is repeated on each ball across the two diameters at right angles to the initial position and to each other.

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1967 - Wording of the Rule

Deformation rule amended & metric units added throughout Rule 3. Appendix amended

3. –The ball shall have a uniform outer surface and shall be white in colour. If there are any seams they shall be stitchless. The ball shall be more than two and a half inches (6.350 cm) and less than two and five-eighths inches (6.668 cm) in diameter, and more than two ounces (56.70 grams) and less than two and one-sixteenth ounces (58.47 grams) in weight. The ball shall have a bound of more than 53 inches (134.6 cm) and less than 58 inches (147.3 cm) when dropped 100 inches (254.0 cm) upon a concrete base. The ball shall have a forward deformation of more than .230 of an inch (.584 cm) and less than .290 of an inch (.737 cm) and a return deformation of more than .355 of an inch (.902 cm) and less than .425 of an inch (1.080 cm) at 18lb. (8.165kg) load. The two deformation figures shall be the averages of three individual readings along three axes of the ball and no two individual readings shall differ by more than .030 of an inch (.076 cm) in each case. All tests for bound, size and deformation shall be made in accordance with the Regulations in the Appendix hereto.

NOTE - At the Annual General Meeting of the I.L.T.F. held on 12th July, 1967, it was agreed that for the time being non-pressurised balls and low-pressure balls may not be used in the International Lawn Tennis Championship (Davis Cup), unless mutually agreed by the two nations taking part in any particular event.

APPENDIXFormally as 1966 “Appendix (Experimental)” (i) to (vi) - see above. Appendix B deleted.

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1969 - Wording of the Rule

Metric decimal units rounded up. Footnote to Rule 3 deleted

3. –The ball shall have a uniform outer surface and shall be white in colour. If there are any seams they shall be stitchless. The ball shall be more than two and a half inches (6.35 cm) and less than two and five-eighths inches (6.67 cm) in diameter, and more than two ounces (56.7 grams) and less than two and one-sixteenth ounces (58.5 grams) in weight. The ball shall have a bound of more than 53 inches (135 cm) and less than 58 inches (147 cm) when dropped 100 inches (254 cm) upon a concrete base. The ball shall have a forward deformation of more than .230 of an inch (.58 cm) and less than .290 of an inch (.74 cm) and a return deformation of more than .355 of an inch (.90 cm) and less than .425 of an inch (1.08 cm) at 18lb. (8.165kg) load. The two deformation figures shall be the averages of three individual readings along three axes of the ball and no two individual readings shall differ by more than .030 of an inch (.08 cm) in each case. All tests for bound, size and deformation shall be made in accordance with the Regulations in the Appendix hereto.

APPENDIX

(ii) Unless otherwise specified the limits are for a test conducted in an atmospheric pressure resulting in a barometric reading of approximately 30 inches (76 cm).

(iii) Other standards may be fixed for localities where the average temperature, humidity or average barometric pressure at which the game is being played differ materially from 68° Fahrenheit (20° Centigrade), 60% and 30 inches (76 cm) respectively. Applications for such adjusted standards may be made by any National Association to the International Lawn Tennis Federation and if approved shall be adopted for such localities.

(iv) In all tests for diameter a ring gauge shall be used, consisting of a metal plate, preferably non-corrosive, of a uniform thickness of one-eighth of an inch (.32 cm), in which there are two circular openings 2.575 inches (6.54 cm) and 2.700 inches (6.86 cm) in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of one-sixteenth of an inch (.16 cm). The ball shall not drop through the smaller opening by its own weight and shall drop through the larger opening by its own weight.

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1972 - Wording of the Rule

Colour of ball amended Specifications for forward and return deformation widened

3. The ball shall have a uniform outer surface and shall be white or yellow in colour.… The ball shall have a forward deformation of more than .220 of an inch (.56 cm) and less than .290 of an inch (.74 cm) and a return deformation of more than .350 of an inch (.89 cm) and less than .425 of an inch (1.08 cm) at 18lb. (8.165kg) load….

Rule 3 – Colour – Very few reports have been received from the National Associations. However, from reports which have been studied it appears that yellow balls should be allowed for tournament play.

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1974

APPENDIX becomes APPENDIX A (content remains the same)

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1978 - Wording of the Rule

Small amendment to end of Rule 3

3. -…All tests for bound, size and deformation shall be made in accordance with the Regulations in Appendix A hereto.

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1981 - Wording of the Rule

Reversion of 1978 amendment

3 …All tests for bound, size and deformation shall be made in accordance with the Regulations in the Appendix hereto. APPENDIX A becomes APPENDIX (content remains the same)

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1989 - Wording of the Rule 

Addition of specifications for high altitude balls at the end of Rule 3

….For play above 4.000 feet (1219m) in altitude above sea level, two additional types of ball may be used. The first type is identical to those described above except that the bound shall be more than 48 inches (121.92 cm) and less than 53 inches (135 cm) and shall have an internal pressure that is greater than the external pressure. This type of tennis ball is commonly known as a pressurised ball. The second type is identical to those described above except that they shall have a bound of more than 53 inches (135 cm) and less than 58 inches (147 cm) and shall have an internal pressure that is approximately equal to the external pressure and have been acclimatised for 60 days or more at the altitude of the specific tournament. This type of tennis ball is commonly known as a zero-pressure or non-pressurised ball.All tests for bound, size and deformation shall be made in accordance with the regulations in Appendix I. APPENDIX becomes APPENDIX I.

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1996 - Wording of the Rule

Return deformation spec amended

…The ball shall have a forward deformation of more than .220 of an inch (.56 cm) and less than .290 of an inch (.74 cm) and a return deformation of more than .315 of an inch (.80 cm) and less than .425 of an inch (1.08 cm) at 18lb. (8.165kg) load….

Justification for the amendment

After lengthy discussions with tennis ball manufacturers over the past eighteen months, they requested a revision to lower the return deformation specification to enable them to produce a ball more suitable for the “market place” and for use on slower courts.

During this period, manufacturers have been permitted to have balls approved providing they were within the trial limit (.80cm).

The Committee considered this lower limit to be acceptable and the revised specification will enable manufacturers to produce balls for different surfaces without contravening the new limits.

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1997 - Wording of the Rule

1969 amendment partly reverted – increasing decimal places shown in Rule 3 and Appendix I (iv) First sentence amended to include fabric cover. New paragraph added at end – introduction of ITF Approval

The Ball - The ball shall have a uniform outer surface consisting of a fabric cover and shall be white or yellow in colour. If there are any seams they shall be stitchless. The ball shall be more than two and a half inches (6.350 cm) and less than two and five-eighths inches (6.668 cm) in diameter, and more than two ounces (56.7 grams) and less than two and one-sixteenth ounces (58.5 grams) in weight. The ball shall have a bound of more than 53 inches (134.62 cm) and less than 58 inches (147.32 cm) when dropped 100 inches (254.00 cm) upon a concrete base. The ball shall have a forward deformation of more than .220 of an inch (.559 cm) and less than .290 of an inch (.737 cm) and a return deformation of more than .315 of an inch (.800 cm) and less than .425 of an inch (1.080 cm) at 18lb. (8.165kg) load. The two deformation figures shall be the averages of three individual readings along three axes of the ball and no two individual readings shall differ by more than .030 of an inch (.076 cm) in each case.

For play above 4.000 feet (1219m) in altitude above sea level, two additional types of ball may be used. The first type is identical to those described above except that the bound shall be more than 48 inches (121.92 cm) and less than 53 inches (134.62 cm) and shall have an internal pressure that is greater than the external pressure. This type of tennis ball is commonly known as a pressurised ball. The second type is identical to those described above except that they shall have a bound of more than 53 inches (134.62 cm) and less than 58 inches (147.32 cm) and shall have an internal pressure that is approximately equal to the external pressure and have been acclimatised for 60 days or more at the altitude of the specific tournament. This type of tennis ball is commonly known as a zero-pressure or non-pressurised ball. All tests for bound, size and deformation shall be made in accordance with the regulations in Appendix I. The International Tennis Federation shall rule on the question of whether any ball or prototype complies with the above specifications or is otherwise approved, for play. Such ruling may be taken on its own initiative, or upon application by any party with a bona fide interest therein, including any player, equipment manufacturer or National Association or members thereof. Such rulings and applications shall be made in accordance with the applicable review and hearing procedures of the International Tennis Federation, copies of which may be obtained from the Federation.

APPENDIX I

(iv) In all tests for diameter a ring gauge shall be used consisting of a metal plate, preferably non-corrosive, of a uniform thickness of one-eighth of an inch (.318 cm) in which there are two circular openings 2.575 inches (6.541 cm) and 2.700 inches (6.858 cm) in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of one-sixteenth of an inch (.159 cm). The ball shall not drop through the smaller opening by its own weight and shall drop through the larger opening by its own weight.

Justification for the amendment

The Committee considers that it is necessary to further define the construction of the tennis ball to include reference to a ball with a fabric cover. This is to prevent the possible introduction of a new ball which may fulfil the current requirements of Rule 3 but could be a rubber or plastic moulded core with no cover and may therefore exhibit aerodynamic properties which could affect the nature of the game.

It also considers that, for testing purposes, it is necessary to amend the existing Rule 3 to ensure that figures given as metric equivalents to the standard imperial units are more accurately represented. To achieve this it is the recommendation of the Committee that the metric figures are calculated to three decimal places instead of two as per the current Rule.

The Committee also recommends that Rule 3 be amended to include a statement advising that the ITF shall rule on the question of whether a ball complies with the regulations. This statement is similar to that already included in Rule 4 – The Racket, and is considered to be necessary in the event that any ball be submitted for approval which, whilst fulfilling the requirements of Rule 3, may feature unexpected characteristics which would affect the nature of the game.

The Committee recommends that Appendix 1 be amended to ensure that the figures shown as metric equivalents to the standard imperial units are more accurately represented for the purposes of testing. To achieve this it is recommended that the metric figures are calculated to three decimal places instead of two as per the current regulation.

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1998 - Wording of the Rule

Amendment to comment re size in Rule 3. Footnote to Rule 3 – re Official listing: ITF Approved balls

….If there are any seams they shall be stitchless.The ball shall conform to the requirements specified in Appendix I (Regulations for making tests specified in Rule 3) Section iv for size and be more than two ounces (56.7 grams) and less than two and one-sixteenth ounces (58.5 grams) in weight….

Note: Any ball to be used in a tournament which is played under the Rules of Tennis, must be named on the official ITF list of approved balls issued by the International Tennis Federation.

Justification for the amendment

The Committee considers it necessary to amend Rule 3 to clarify the long standing confusion resulting from the current disparity between Rule 3 and Appendix 1 of the Rules of Tennis with regards to the figures given for the size of a tennis ball. The figures specified in Rule 3 are considered to be meaningless without reference being made to an appropriate test method and the ball manufacturing industry has, for many years, used the Appendix as the definitive specification. The amendment does not in any way amend the traditional dimension of the ball but only seeks to correct sources of confusion within the Rules of Tennis.

The Committee believes it is necessary to add this Note to Rule 3 to encourage all ball manufacturers and National Associations to submit balls to the ITF for testing and approval on an annual basis. This would help ensure that balls are not developed which do not conform to the Rules of Tennis and should ensure that the specification given in the Rules of Tennis becomes globally accepted as the definitive standard. The Committee recommends acceptance of the above proposal.

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1999 - Wording of the Rule

Reference to Appendix II at end of Rule 3. Appendix I (v) amended

…Such rulings and applications shall be made in accordance with the applicable Review and Hearing Procedures of the International Tennis Federation (see Appendix II).

APPENDIX I

(v) In all tests for deformation conducted under Rule 3, the machine designed by Percy Herbert Stevens and patented in Great Britain under Patent No. 230250, together with the subsequent additions and improvements thereto, including the modifications required to take return deformations shall be employed. Other machines may be specified which give equivalent readings to the Stevens machine and these may be used for testing ball deformation where such machines have been given approval by the International Tennis Federation.

Justification for the amendment

The Board, through its Technical Committee, has recently carried out exhaustive studies on more modern and appropriate methods of measuring tennis ball compression than the Stevens machine and is now confident that such methods can be developed which simultaneously provide more data and eliminate the operator dependency inherent in the design of the Stevens machine. Such equipment is, by definition, more complex than the traditional Stevens machine but will allow easier and more accurate international standardisation of ball properties to be achieved. It is also considered that in the interests of standardisation, the Appendix should be amended to state that only the International Tennis Federation has authority to approve such equipment for testing required for balls to obtain ITF Approval. The Board recommends acceptance of this proposal.

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2000 - Wording of the Rule

New introductory sentence to Rule 3. Mass spec. changed. Note 2 added Appendix I: (iv) amended (vii) added

3. THE BALL

Balls that are approved for play under the Rules of Tennis must comply with the following specifications:

a. The ball shall have a uniform outer surface consisting of a fabric cover and shall be white or yellow in colour. If there are any seams they shall be stitchless.

b. The ball shall be more than two and a half inches (6.350 cm) and less than two and five-eighths inches (6.668 cm) in diameter, and more than two ounces (56.0 grams) and less than two and one-sixteenth ounces (59.4 grams) in weight.

c. The ball shall have a bound of more than 53 inches (134.62 cm) and less than 58 inches (147.32 cm) when dropped 100 inches (254.00 cm) upon a concrete base. The ball shall have a forward deformation of more than .220 of an inch (.559 cm) and less than .290 of an inch (.737 cm) and a return deformation of more than .315 of an inch (.800 cm) and less than .425 of an inch (1.080 cm) at 18lb. (8.165kg) load. The two deformation figures shall be the averages of three individual readings along three axes of the ball and no two individual readings shall differ by more than .030 of an inch (.076 cm) in each case.d. For play above 4.000 feet (1219m) in altitude above sea level, two additional types of ball may be used. The first type is identical to those described above except that the bound shall be more than 48 inches (121.92 cm) and less than 53 inches (134.62 cm) and shall have an internal pressure that is greater than the external pressure. This type of tennis ball is commonly known as a pressurised ball. The second type is identical to those described above except that they shall have a bound of more than 53 inches (134.62 cm) and less than 58 inches (147.32 cm) and shall have an internal pressure that is approximately equal to the external pressure and have been acclimatised for 60 days or more at the altitude of the specific tournament. This type of tennis ball is commonly known as a zero-pressure or non-pressurised ball.

e. All tests for bound, size and deformation shall be made in accordance with the regulations in Appendix I.

f. The International Tennis Federation shall rule on the question of whether any ball or prototype complies with the above specifications or is otherwise approved, for play. Such ruling may be taken on its own initiative, or upon application by any party with a bona fide interest therein, including any player, equipment manufacturer or National Association or members thereof. Such rulings and applications shall be made in accordance with the applicable Review and Hearing Procedures of the International Tennis Federation (see Appendix II).

Note 2: From 1st January 2000 until 31st December 2001 two further types of tennis ball may be used on an experimental basis.

The first type is identical to those described in paragraphs a. to c. above except that the ball shall have a forward deformation of more than .195 inches (.495 cm) and less than .235 inches (.597 cm) and return deformation of more than .295 inches (.749 cm) and less than .380 inches (.965 cm). This type of ball shall be described as ball Type 1 and may be used in either a pressurised or non-pressurised form.

Another type is identical to those described in paragraphs a. to c. above except that the size shall be more than 2.750 inches (6.985 cm) and less than 2.875 inches (7.302 cm) in diameter as determined by ring gauges and detailed in Appendix I section (iv). This type of ball shall be described as ball Type 3 and may be used in either a pressurised or non-pressurised form.

All other types of ball defined by Rule 3 shall be described as ball Type 2. For the purposes of tournaments played under this experiment:1. Ball Type 1 (fast) should only be used for play on court surface types which have been classified as Category 1 (slow pace) (see Appendix I).2. Ball Type 2 (medium) should only be used for play on court surface types which have been classified as Category 2 (medium/medium-fast pace) (see Appendix I).3. Ball Type 3 (slow) should only be used for play on court surface types which have been classified as Category 3 (fast pace) (see Appendix I).

For non-professional play any ball type may be used on any surface type.


APPENDIX I

(iv) In all tests for diameter a ring gauge shall be used consisting of a metal plate, preferably non-corrosive, of a uniform thickness of one-eighth of an inch (.318 cm). In the case of Type 1 (fast) and Type 2 (medium) balls there shall be two circular openings in the plate measuring 2.575 inches (6.541 cm) and 2.700 inches (6.858 cm) in diameter respectively. In the case of Type 3 (slow) balls there shall be two circular openings in the plate measuring 2.750 inches (6.985 cm) and 2.875inches (7.302 cm) in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of one-sixteenth of an inch (.159 cm). The ball shall not drop through the smaller opening by its own weight and shall drop through the larger opening by its own weight.

(vii) CLASSIFICATION OF COURT SURFACE PACE - The test method to be used for determining the pace of a court surface is test method ITF CS 01/01 (ITF Surface Pace Rating) as described in the ITF publication entitled “An initial ITF study on performance standards for tennis court surfaces”.

Court surfaces which are found to have an ITF Surface Pace Rating of between 0 and 35 shall be classified as being Category 1 (slow pace). Examples of court surface types which conform to this classification will include most clay courts and other types of unbound mineral surface.

Court surfaces which are found to have an ITF Surface Pace Rating of between 30 and 45 shall be classified as being Category 2 (medium/medium-fast pace). Examples of court surface types which conform to this classification will include most hardcourts with various acrylic type coatings plus some textile surfaces.

Court surfaces which are found to have an ITF Surface Pace Rating of over 40 shall be classified as being Category 3 (fast pace). Examples of court surface types which conform to this classification will include most natural grass, artificial turf and some textile surfaces.

N.B. The proposed overlap in ITF Surface Pace Rating values for the above categories is to allow some initial latitude in ball selection for the period of the experiment.

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2001 - Wording of the Rule

Reference to Appendix II at end of Rule 3 changes to Appendix III.

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2002 - Wording of the Rule

Type 1 and Type 3 balls formally included in Rules. Amendment to Rule 3 c. & d. Note 2 deleted. Case 1 added. Appendix I: (iv) amended (vii) 2 minor amendments

3. THE BALL c. More than one type of ball is specified. Each ball shall have a bound of more than 53 inches (134.62 cm) and less than 58 inches (147.32 cm) when dropped 100 inches (254.00 cm) upon a flat, rigid surface e.g. concrete. Ball Type 1 (fast speed) shall have a forward deformation of more than .195 inches (.495 cm) and less than .235 inches (.597 cm) and return deformation of more than .295 inches (.749 cm) and less than .380 inches (.965 cm) at 18 lb. (8.165kg) load. Ball Types 2 (medium speed) and 3 (slow speed) shall have a forward deformation of more than .220 inches (.559 cm) and less than .290 inches (.737 cm) and return deformation of more than .315 inches (.800 cm) and less than .425 inches (1.080 cm) at 18 lb. (8.165kg) load. The two deformation figures shall be the averages of three individual readings along three axes of the ball and no two individual readings shall differ by more than .030 inches (.076 cm) in each case.

d. For play above 4,000 feet (1219m) in altitude above sea level, two additional types of ball may be used.(i). The first type is identical to Ball Type 2 (medium speed) as defined above except that the ball shall have a bound of more than 48 inches (121.92 cm) and less than 53 inches (134.62 cm) and shall have an internal pressure that is greater than the external pressure. This type of tennis ball is commonly known as a pressurised ball.

(ii).The second type is identical to Ball Type 2 (medium speed) as defined above except that the ball shall have a bound of more than 53 inches (134.62 cm) and less than 58 inches (147.32 cm) and shall have an internal pressure that is approximately equal to the external pressure and have been acclimatised for 60 days or more at the altitude of the specific tournament. This type of tennis ball is commonly known as a zero-pressure or non-pressurised ball. The third type of ball which is recommended for use for play on any court surface type above 4,000 feet (1219m) in altitude is the Ball Type 3 (slow speed), as defined above.

Case 1: Which ball type should be used on which court surface?

Decision. 3 different types of ball are approved for play under the Rules of Tennis, however:a. Ball Type 1 (fast speed) is intended for play on slow pace court surfaces (see Appendix I).b. Ball Type 2 (medium speed) is intended for play on medium/ medium-fast pace court surfaces (see Appendix I).c. Ball Type 3 (slow speed) is intended for play on fast pace court surfaces (see Appendix I).

APPENDIX I

iv. In all tests for diameter a ring gauge shall be used consisting of a metal plate, preferably non-corrosive, of a uniform thickness of on-eighth of an inch (.318 cm). In the case of Ball Type 1 (fast speed) and Ball Type 2 (medium speed) balls there shall be two circular openings in the plate measuring 2.575 inches (6.541 cm) and 2.700 inches (6.858 cm) in diameter respectively. In the case of Ball Type 3 (slow speed) balls there hall be two circular openings in the plate measuring 2.750 inches 6.985 cm) and 2.875 inches (7.302 cm) in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of one-sixteenth of an inch (.159 cm). The ball shall not drop through the maller opening by its own weight and shall drop through the larger pening by its own weight.

vii. The ITF test method used for determining the pace of a court surface…

N.B. The proposed overlap in ITF Surface Pace Rating values for the above categories is to allow some latitude in ball selection.

Justification for the amendment

The Rules of Tennis Committee and the Technical Commission have recommended that Rule 3 – The Ball and Appendix 1 paragraphs iv and vii be amended, and a new Case 1 be inserted, to ratify the introduction of two new types of tennis ball. Following a two-year period of experimentation and detailed study, the Technical Commission has concluded that the objectives of the experiment have been successfully achieved and that the amendment will be of significant benefit in the development of tennis. Specifically the experiment has confirmed the following:

1. The Type 3 oversize ball is slower in pace and therefore allows recreational players more time to formulate their return stroke. This can be shown to lead to longer rallies of up to 25%. It can therefore be concluded that the Type 3 ball on any surface will make the learning of tennis easier and more fun for the majority of players.

2. Although not its primary purpose, the Type 3 oversize ball if used on faster surfaces can also help curb where necessary the dominance of the serve and corresponding lack of rallies in the professional game.

N.B. It should also be noted that the Technical Commission has proposed an amendment to the regulation defining high altitude balls. The current regulation defines two types of high altitude ball which are widely accepted to be not entirely satisfactory for such purposes. The ideal high altitude ball is currently considered to be one which accounts for the lower air density above 4000ft. and the difference in atmospheric pressure between high altitude and sea level. The current Type 3 oversize ball satisfies the former requirement and can therefore be recommended for play above 4000ft. on any type of surface.

It should be stressed that the Rules of Tennis Committee and the Technical Commission believe that the proposed terminology linking ball type with court surface type provides the appropriate guidance whilst being non-mandatory. The Board of Directors recommends acceptance of this proposal.

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2003 - Wording of the Rule

Amendment to Ball Type 1 return deformation in Rule 3

Ball Type 1 (fast speed) shall have a forward deformation of more than .195 inches (.495cm) and less than .235 inches (.597cm) and return deformation of more than .265 inches (.673cm) and less than .360 inches (.914cm) at 18lb. (8.165kg) load.

Justification for the amendment

The deformation characteristics for the Type 1 ball were based on those of a ball that was already being manufactured by a particular company, and which lay outside the specification for the Type 2 ball. Subsequently, however, it was discovered that other companies – whose materials and manufacturing processes were slightly different – experienced difficulty in making balls that consistently lay within these boundaries. As a result, only one brand of Type 1 ball has been ITF Approved.

Following a request to ball manufacturers, two suggestions for an amendment to the current specification were made. Based on a consideration of all available information, and following consultation with ball manufacturers. The ITF Technical Commission subsequently agreed the proposal described above, the aim of which is to provide an attainable specification for return deformation and, therefore, encourage production of the Type 1 ball. The Board of Directors recommends acceptance of the above amendment.

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2004 - Wording of the Rule - all new text

The format and presentation of the rules has been revised into a more modern language and easier to follow sequence. This has resulted in a reduction in the number of rules, and for reference purposes the old rule number is shown in brackets.

3. THE BALL (OLD 3, 13, 27 & 32) Balls, which are approved for play under the Rules of Tennis, must comply with the specifications in Appendix I.

The International Tennis Federation shall rule on the question of whether any ball or prototype complies with Appendix I or is otherwise approved, or not approved, for play. Such ruling may be taken on its own initiative, or upon application by any party with a bona fide interest therein, including any player, equipment manufacturer or National Association or members thereof. Such rulings and applications shall be made in accordance with the applicable Review and Hearing Procedures of the International Tennis Federation (see Appendix VI).

The event organisers must announce in advance of the event: a. The number of balls for play (2, 3, 4 or 6).b. The ball change policy, if any.

Ball changes, if any, can be made either:

i. After an agreed odd number of games, in which case, the first ball change in the match shall take place two games earlier than for the rest of the match, to make allowance for the warm-up. A tie-break game counts as one game for the ball change. A ball change shall not take place at the beginning of a tie-break game. In this case, the ball change shall be delayed until the beginning of the second game of the next set; or

ii. At the beginning of a set If a ball gets broken during play, the point shall be replayed.

Case 1: If a ball is soft at the end of a point, should the point be replayed?Decision: If the ball is soft, not broken, the point shall not be replayed.

Note: Any ball to be used in a tournament which is played under the Rules of Tennis, must be named on the official ITF list of approved balls issued by theInternational Tennis Federation.

APPENDIX I

a. The ball shall have a uniform outer surface consisting of a fabric cover and shall be white or yellow in colour. If there are any seams they shall be stitchless.

b. The ball shall conform to these requirements and have a weight (mass) of more than 1.975 ounces (56.0 grams) and less than 2.095 ounces (59.4 grams).

c. More than one type of ball is specified. Each ball shall have a bound of morethan 53 inches (134.62 cm) and less than 58 inches (147.32 cm) when dropped 100 inches (254.00 cm) upon a flat, rigid surface e.g. concrete. Ball Type 1 (fast speed) shall have a forward deformation of more than .195 inches (.495 cm) and less than .235 inches (.597 cm) and return deformation of more than .265 inches (.673 cm) and less than .360 inches (.914 cm) at 18 lb (8.165 kg) load. Ball Types 2 (medium speed) and 3 (slow speed) shall have a forward deformation of more than .220 inches (.559 cm) and less than .290 inches (.737 cm) and return deformation of more than .315 inches (.800 cm) and less than .425 inches (1.080 cm) at 18 lb (8.165 kg) load. The two deformation figures shall be the averages of three individual readings along three axes of the ball and no two individual readings shall differ by more than .030 inches (.076 cm) in each case.

d. For play above 4,000 feet (1219 m) in altitude above sea level, two additional types of ball may be used.

i. The first type is identical to Ball Type 2 (medium speed) as defined above except that the ball shall have a bound of more than 48 inches (121.92 cm) and less than 53 inches (134.62 cm) and shall have an internal pressure that isgreater than the external pressure. This type of tennis ball is commonly known as a pressurised ball.

ii. The second type is identical to Ball Type 2 (medium speed) as defined above except that the ball shall have an internal pressure that is approximately equal to the external pressure and have been acclimatised for 60 days or more at the altitude of the specific tournament. This type of tennis ball is commonly known as a zero-pressure or non-pressurised ball.

The third type of ball which is recommended for use for play on any court surface type above 4,000 feet (1219 m) in altitude is the Ball Type 3 (slow speed), as defined above.

e. All tests for bound, size and deformation shall be made in accordance with the regulations below.

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2006 - Wording of the Rule - all new text

APPENDIX I - THE BALL

a. The ball shall have a uniform outer surface consisting of a fabric cover and shall be white or yellow in colour. If there are any seams they shall be stitchless.

b. More than one type of ball is specified. The ball shall conform to the requirements shown in the table below.

Ball Specifications - Appendix 1 Table

Notes:
1. This ball may be pressurised or pressureless. The pressureless ball shall have an internal pressure that is no greater than 1 psi (7 kPa) and may be used for high altitude play above 4,000 feet (1,219 m) above sea level and shall have been acclimatised for 60 days or more at the altitude of the specific tournament.
2.This ball is also recommended for high altitude play on any court surface type above 4,000 feet (1,219 m) above sea level.
3.This ball is pressurised and is an additional ball specified for high altitude play above 4,000 feet (1,219 m) above sea level only.
4.The deformation shall be the average of a single reading along each of three perpendicular axes. No two individual readings shall differ by more than .030 inches (.076 cm).

c. All tests for rebound, size and deformation shall be made in accordance with the regulations below.

REGULATIONS FOR MAKING TESTS

i. Unless otherwise specified all tests shall be made at a temperature of approximately 68º Fahrenheit (20º Celsius), a relative humidity of approximately 60% and, unless otherwise specified, an atmospheric pressure of approximately 30 inches Hg (102 kPa). All balls shall be removed from their container and kept at the recognised temperature and humidity for 24 hours prior to testing, and shall be at that temperature and humidity when the test is commenced.

ii. Other standards may be fixed for localities where the average temperature, humidity or average barometric pressure at which the game is being played differ materially from 68º Fahrenheit (20º Celsius), 60% relative humidity and 30 inches Hg (102 kPa) respectively. Applications for such adjusted standards may be made by any National Association to the International Tennis Federation and, if approved, shall be adopted for such localities.

iii. In all tests for diameter, a ring gauge shall be used consisting of a metal plate, preferably non-corrosive, of a uniform thickness of one-eighth of an inch (0.318 cm). In the case of Ball Type 1 (fast speed) and Ball Type 2 (medium speed) balls there shall be two circular openings in the plate measuring 2.575 inches (6.541 cm) and 2.700 inches (6.858 cm) in diameter respectively. In the case of Ball Type 3 (slow speed) balls there shall be two circular openings in the plate measuring 2.750 inches (6.985 cm) and 2.875 inches (7.303 cm) in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of one-sixteenth of an inch (0.159 cm). The ball shall not drop through the smaller opening by its own weight in any orientation and shall drop through the larger opening by its own weight in all orientations.

iv. In all tests for deformation conducted under Rule 3, the machine designed by Percy Herbert Stevens and patented in Great Britain under Patent No. 230250, together with the subsequent additions and improvements thereto, including the modifications required to take return deformations, shall be employed. Other machines may be specified which give equivalent readings to the Stevens machine and these may be used for testing ball deformation where such machines have been given approval by the International Tennis Federation.

v. The procedure for carrying out tests is as follows and should take place in the order specified:

a. Pre-compression – before any ball is tested it shall be steadily compressed by approximately one inch (2.54 cm) on each of three diameters at right angles to one another in succession; this process to be carried out three times (nine compressions in all). All tests are to be completed within two hours of pre-compression.

b. Weight (mass) test.

c. Size test (as in paragraph iii. above).

d. Deformation test – the ball is placed in position on the modified Stevens machine so that neither platen of the machine is in contact with the cover seam. The contact weight is applied, the pointer and the mark brought level, and the dials set to zero. The test weight is placed on the beam in a position that is equivalent to a load of 18 lb (8.2 kg) on the ball, after which the wheel is turned at a uniform speed such that five seconds elapse from the instant the beam leaves its seat until the pointer is brought level with the mark. When turning ceases the reading is recorded (forward deformation). The wheel is turned again until figure ten is reached on the scale (one inch {2.54 cm} deformation). The wheel is then rotated in the opposite direction at a uniform speed (thus releasing pressure) until the beam pointer again coincides with the mark. After waiting ten seconds, the pointer is adjusted to the mark if necessary. The reading is then recorded (return deformation). This procedure is repeated on each ball across the two diameters at right angles to the initial position and to each other.

e. Rebound test (as above) – the ball is dropped from 100 inches (254 cm) onto a smooth rigid and horizontal surface. Measurements of both drop height and rebound height are to be taken from the surface to the bottom of the ball.

CLASSIFICATION OF COURT SURFACE PACE

The ITF test method used for determining the pace of a court surface is test method ITF CS 01/01 (ITF Surface Pace Rating) as described in the ITF publication entitled “An initial ITF study on performance standards for tennis court surfaces”.

Court surfaces which are found to have an ITF Surface Pace Rating of between 0 and 35 shall be classified as being Category 1 (slow pace). Examples of court surface types which conform to this classification will include most clay courts and other types of unbound mineral surface.

Court surfaces which are found to have an ITF Surface Pace Rating of between 30 and 45 shall be classified as being Category 2 (medium/medium-fast pace). Examples of court surface types which conform to this classification will include most hardcourts with various acrylic type coatings plus some textile surfaces.

Court surfaces which are found to have an ITF Surface Pace Rating of over 40 shall be classified as being Category 3 (fast pace). Examples of court surface types which conform to this classification will include most natural grass, artificial turf and some textile surfaces.

Note: The proposed overlap in ITF Surface Pace Rating values for the above categories is to allow some latitude in ball selection.

Case 1: Which ball type should be used on which court surface?

Decision: 3 different types of balls are approved for play under the Rules of Tennis, however:
a. Ball Type 1 (fast speed) is intended for play on slow pace court surfaces
b. Ball Type 2 (medium speed) is intended for play on medium/medium-fast pace court surfaces
c. Ball Type 3 (slow speed) is intended for play on fast pace court surfaces

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2008 - Wording of the Rule - all new text

CLASSIFICATION OF COURT PACE

The ITF test method used for determining the pace of a court surface is ITF CS 01/02 (ITF Court Pace Rating) as described in the ITF publication entitled “ITF guide to test methods for tennis court surfaces”.

Court surfaces which have an ITF Court Pace Rating of 0 to 29 shall be classified as being Category 1 (slow pace). Examples of court surface types which conform to this classification will include most clay courts and other types of unbound mineral surface.

Court surfaces which have an ITF Court Pace Rating of 30 to 34 shall be classified as being Category 2 (medium-slow pace), while court surfaces with an ITF Court Pace Rating of 35 to 39 shall be classified as being Category 3 (medium pace). Examples of court surface types which conform to this classification will include most acrylic coated surfaces plus some carpet surfaces.

Court surfaces with an ITF Court Pace Rating of 40 to 44 shall be classified as being Category 4 (medium-fast pace), while court surfaces which have an ITF Court Pace Rating of 45 or more shall be classified as being Category 5 (fast pace). Examples of court surface types which conform to this classification will include most natural grass, artificial grass and some carpet surfaces.

Case 1: Which ball type should be used on which court surface?

Decision: 3 different types of balls are approved for play under the Rules of Tennis, however:

a.    Ball Type 1 (fast speed) is intended for play on slow pace court surfaces

b.    Ball Type 2 (medium speed) is intended for play on medium-slow, medium and medium-fast pace court surfaces

c.    Ball Type 3 (slow speed) is intended for play on fast pace court surfaces

Justification for the amendment

The final section of Appendix 1 has been revised to change the ‘Classification of Surface Pace’ section to reflect the new ‘Court Pace’ Classification programme and the move from 3 to 5 categories of classification. This change will come into force at the same time as the 2008 Davis Cup and Fed Cup regulations to impose limits on pace for courts used at World Group and Group 1 ties.

It also includes a reference to the new ITF GUIDE TO TEST METHODS FOR TENNIS COURT SURFACES, which is now contained in the ITF Technical annual publication entitled:  ITF Approved Tennis Balls, Classified Surfaces & Recognised Courts – A guide to products & test methods.

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2009 - Wording of the Rule

 APPENDIX I - THE BALL

a.    The ball shall have a uniform outer surface consisting of a fabric cover and shall be white or yellow in colour. If there are any seams they shall be stitchless.

b.    More than one type of ball is specified. The ball shall conform to the requirements shown in the table below.

 

  TYPE 1
 (FAST)
TYPE 2
 (MEDIUM)
1 
TYPE 3
(SLOW)
2
HIGH ALTITUDE3
MASS (WEIGHT) 56.0-59.4 grams (1.975-2.095 ounces) 56.0-59.4 grams(1.975-2.095 ounces) 56.0-59.4 grams(1.975-2.095 ounces)  56.0-59.4 grams(1.975-2.095 ounces)
SIZE 6.54-6.86 cm(2.57-2.70 inches) 6.54-6.86 cm(2.57-2.70 inches) 7.00-7.30 cm(2.76-2.87 inches) 6.54-6.86 cm(2.57-2.70 inches)
REBOUND 135-147 cm(53-58 inches) 135-147 cm(53-58 inches) 135-147 cm(53-58 inches) 122-135 cm(48-53 inches)
FORWARD DEFORMATION4  0.495-0.600 cm(0.195-0.236 inches) 0.560-0.740 cm(0.220-0.291 inches) 0.560-0.740 cm(0.220-0.291 inches) 0.560-0.740 cm(0.220-0.291 inches)
RETURN DEFORMATION4 0.670-0.915 cm(0.264-0.360 inches) 0.800-1.080 cm(0.315-0.425 inches) 0.800-1.080 cm(0.315-0.425 inches) 0.800-1.080 cm(0.315-0.425 inches)

Notes:

1 This ball may be pressurised or pressureless. The pressureless ball shall have an internal pressure that is no greater than 7 kPa (1 psi) and may be used for high altitude play above 1,219 m (4,000 feet) above sea level and shall have been acclimatised for 60 days or more at the altitude of the specific tournament.

2 This ball is also recommended for high altitude play on any court surface type above 1,219 m (4,000 feet) above sea level.

3 This ball is pressurised and is an additional ball specified for high altitude play above 1,219 m (4,000 feet) above sea level only.

4 The deformation shall be the average of a single reading along each of three perpendicular axes. No two individual readings shall differ by more than .075 cm (.030 inches).

c.     All tests for rebound, size and deformation shall be made in accordance with the Regulations for making tests below.

REGULATIONS FOR MAKING TESTS

 i.  Unless otherwise specified all tests shall be made at a temperature of approximately 20º Celsius (68º Fahrenheit), a relative humidity of approximately 60% and, unless otherwise specified, an atmospheric pressure of approximately 102 kPa (30 inches Hg). All balls shall be removed from their container and kept at the recognised temperature and humidity for 24 hours prior to testing, and shall be at that temperature and humidity when the test is commenced.

ii.   Other standards may be fixed for localities where the average temperature, humidity or average barometric pressure at which the game is being played differ materially from 20º Celsius (68º Fahrenheit), 60% relative humidity and 102 kPa (30 inches Hg) respectively.

Applications for such adjusted standards may be made by any National Association to the International Tennis Federation and, if approved, shall be adopted for such localities.

iii.   In all tests for diameter, a ring gauge shall be used consisting of a metal plate, preferably non-corrosive, of a uniform thickness of 0.318 cm (0.125 inches). In the case of Ball Type 1 (fast speed) and Ball Type 2 (medium speed) balls there shall be two circular openings in the plate measuring 6.54 cm (2.57 inches) and 6.86 cm (2.70 inches) in diameter respectively. In the case of Ball Type 3 (slow speed) balls there shall be two circular openings in the plate measuring 7.00 cm (2.76 inches) and 7.30 cm (2.87 inches) in diameter respectively. The inner surface of the gauge shall have a convex profile with a radius of 0.160 cm (0.063 inches). The ball shall not drop through the smaller opening by its own weight in any orientation and shall drop through the larger opening by its own weight in all orientations.

iv.  In all tests for deformation conducted under Rule 3, the machine designed by Percy Herbert Stevens and patented in Great Britain under Patent No. 230250, together with the subsequent additions and improvements thereto, including the modifications required to take return deformations, shall be employed. Other machines may be specified which give equivalent readings to the Stevens machine and these may be used for testing ball deformation where such machines have been given approval by the International Tennis Federation.

v.  The procedure for carrying out tests is as follows and should take place in the order specified:

a.  Pre-compression – before any ball is tested it shall be steadily compressed by approximately 2.54 cm (1 inch) on each of three diameters at right angles to one another in succession; this process to be carried out three times (nine compressions in all). All tests are to be completed within two hours of pre-compression.

b.  Weight (mass) test.

c.  Size test (as in paragraph iii. above).

d.  Deformation test – the ball is placed in position on the modified Stevens machine so that neither platen of the machine is in contact with the cover seam. The contact weight is applied, the pointer and the mark brought level, and the dials set to zero. The test weight is placed on the beam in a position that is equivalent to a load of 8.2 kg (18 lb) on the ball, after which the wheel is turned at a uniform speed such that five seconds elapse from the instant the beam leaves its seat until the pointer is brought level with the mark. When turning ceases the reading is recorded (forward deformation). The wheel is turned again until figure ten is reached on the scale (2.54 cm {1 inch} deformation). The wheel is then rotated in the opposite direction at a uniform speed (thus releasing pressure) until the beam pointer again coincides with the mark. After waiting ten seconds, the pointer is adjusted to the mark if necessary. The reading is then recorded (return deformation). This procedure is repeated on each ball across the two diameters at right angles to the initial position and to each other.

e.  Rebound test (as above) – the ball is dropped from 254 cm (100 inches) onto a smooth rigid and horizontal surface. Measurements of both drop height and rebound height are to be taken from the surface to the bottom of the ball.

Justification for the amendment

The specifications in Appendix 1 (The Ball) and Appendix II (The Racket) were amended to follow current scientific convention, and use SI as the primary unit, and Imperial as the secondary unit, thereby standardising the unit of measurement to that used by the tennis industry.  The SI units were rounded, where such rounding (a) has no material effect on the specification, and (b) better reflects the accuracy of the device commonly used to measure the relevant specification.

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2010 - Wording of the Rule

 APPENDIX I - THE BALL

For all measurements in Appendix I, SI units shall take precedence.

a.    The ball shall have a uniform outer surface consisting of a fabric cover and shall be white or yellow in colour. If there are any seams they shall be stitchless.

b.    More than one type of ball is specified. The ball shall conform to the requirements shown in the table below.

  TYPE 1
 (FAST)
TYPE 2
 (MEDIUM)
1 
TYPE 3
(SLOW)
2
HIGH ALTITUDE3
MASS (WEIGHT) 56.0-59.4 grams(1.975-2.095 ounces) 56.0-59.4 grams(1.975-2.095 ounces) 56.0-59.4 grams(1.975-2.095 ounces)  56.0-59.4 grams(1.975-2.095 ounces)
SIZE 6.54-6.86 cm(2.57-2.70 inches) 6.54-6.86 cm(2.57-2.70 inches) 7.00-7.30 cm(2.76-2.87 inches) 6.54-6.86 cm(2.57-2.70 inches)
REBOUND 135-147 cm(53-58 inches) 135-147 cm(53-58 inches) 135-147 cm(53-58 inches) 122-135 cm(48-53 inches)
FORWARD DEFORMATION4  0.50-0.60 cm(0.197-0.236 inches) 0.56-0.74 cm(0.220-0.291 inches) 0.56-0.74 cm(0.220-0.291 inches) 0.56-0.74 cm(0.220-0.291 inches)
RETURN DEFORMATION4 0.67-0.91 cm(0.264-0.358 inches) 0.80-1.08 cm(0.315-0.425 inches) 0.80-1.08 cm(0.315-0.425 inches) 0.80-1.08 cm(0.315-0.425 inches)

Notes:

1 This ball may be pressurised or pressureless. The pressureless ball shall have an internal pressure that is no greater than 7 kPa (1 psi) and may be used for high altitude play above 1,219 m (4,000 feet) above sea level and shall have been acclimatised for 60 days or more at the altitude of the specific tournament.

2 This ball is also recommended for high altitude play on any court surface type above 1,219 m (4,000 feet) above sea level.

3 This ball is pressurised and is an additional ball specified for high altitude play above 1,219 m (4,000 feet) above sea level only.

4 The deformation shall be the average of a single reading along each of three perpendicular axes. No two individual readings shall differ by more than 0.08 cm (0.031 inches).

c.    In addition, the ball shall conform to the requirements for durability as shown in the following table:

  MASS (WEIGHT) REBOUND FORWARD DEFORMATION  RETURN DEFORMATION 
MAXIMUM CHANGE1 
0.4 grams(0.014 ounces) 4.0 cm(1.6 inches) 0.08 cm(0.031 inches) 0.10 cm(0.039 inches)
Notes:

1 The largest permissible change in the specified properties resulting from the durability test described in the current edition of ITF Approved Tennis Balls & Classified Court Surfaces. The durability test uses laboratory equipment to simulate the effects of nine games of play.

d.      All tests for rebound, mass, size, deformation and durability shall be made in accordance with the Regulations described in the current edition of ITF Approved Tennis Balls & Classified Court Surfaces.

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SPECIFIC EQUIPMENT RULES

Follow the links below to find the latest rules and specifications for tennis balls, rackets, courts and player analysis technology:

Balls

Rackets

Courts

Player Analysis Technology

MORE RULES ABOUT BALLS

Follow the links below to find out more about the rules regarding balls including developments to rules over time, Appendix I, and Appendix VI:

Overview

History

Appendix I: The Ball

Appendix VII: 10 and under Tennis Competition