AU2005316194B2 - Method and apparatus for assisting the user of a sports ball to use spin - Google Patents

Description

WO 2006/063391 PCT/AU2005/001879 1 METHOD AND APPARATUS FOR ASSISTING THE USER OF A SPORTS BALL TO USE SPIN This invention relates to an apparatus to assist the user of a sports ball to 5 apply spin or to detect the unintended application of spin to a sports ball. In particular, the invention relates to a ball like structure having a shape that in use provides a useful tool for instruction and feedback to a user of the sports ball. 10 BACKGROUND In many sports, it is beneficial to impart spin on the ball in order to: . curve the ball in the air and/or . deviate the ball off the ground so as to deceive the receiver (or batter) as to the true path of the ball. 15 In other sports, spin is imparted to enable the ball to travel greater distances. There have been prior attempts to make it easier to view the direction of the spin provided to a sports ball. One attempt involves coating the normal 20 playing sports ball with bold contrasting colours, one on each half of the sports ball or other appropriate colour distribution schemes. However, given the speed at which the ball travels and spins in normal play or during practice, it has always been difficult to clearly observe the sometimes-subtle nuances of spin and the resultant flight of the ball. 25 An example of a ball arranged to have an increased rate of spin is that disclosed in U.S. Pat. No. 3,874,663 issued to Kahle. The toy ball of Kahle discloses a hollow ball containing a diametrically extending tube. Two weights are slidably mounted within the tube. Springs urge the weights WO 2006/063391 PCT/AU2005/001879 2 toward the centre of the ball, while cords attached to the weights keep them apart when the user holds the ball and controls the cords. When the ball is thrown and the cords are released, the springs force the weights toward the centre of the ball, thus concentrating the mass distribution of the ball near its 5 centre. The spin velocity of the ball increases in order to conserve angular momentum, and the curve of the ball is enhanced. The Kahle device merely enhances the natural rotational force imparted to the ball by the thrower and does not assist in identification of how it spins to the thrower. 10 A game or practice ball is disclosed in U.S. Pat. No. 5,072,938 issued to Shin, having a rotation produced by an internal weight distribution mechanism to cause the ball to curve dramatically when thrown. The ball has a substantially spherical shell. An axle is located diametrically within, and is connected to the shell. An inertial reference mass in the form of a sphere is located within the 15 shell and is rotatably mounted on the axle. A user released drive means is coupled to the inner sphere and outer shell for rotating the outer shell relative to the inner sphere and portions of the drive so as to impart spin to the shell when the ball is thrown. 20 The invention described herein is in contrast to the described prior attempts to assist users of a sports ball to improve the control they have over the spin they impart to the sports ball or to mechanically assist the user. The aim of this invention is to provide a sports ball of a shape and configuration that allows for the user and an instructor to readily determine visually whether 25 the user of the sports ball is able to control the sports ball when imparting spin. The user of the sports training ball is then able to use the acquired skills on a normal sports ball during play.

WO 2006/063391 PCT/AU2005/001879 3 BRIEF DESCRIPTION OF THE INVENTION In one preferred aspect of the invention a sports training ball for a predetermined sport that uses a sports ball shape that is substantially spherical characterised in that the outer shape of the training sports ball is 5 disc shaped having substantially parallel side surfaces and a spherical circumferential surface. In an aspect of the invention a method of forming a training sports ball for a predetermined sport that uses a sports ball shape that is substantially 10 spherical consists of the following steps: removing two opposed portions of a substantially spherical sports ball used in the predetermined sport to form the outer shape into a disc having substantially parallel side surfaces and a spherical circumferential surface. 15 In another aspect of the invention a further method of forming a training sports ball for a predetermined sport that uses a sports ball shape that is substantially spherical consists of the following steps: joining two parts to form a disc having two substantially parallel 20 outer side surfaces with a spherical circumferential surface. In another aspect of the invention said disc is formed of two substantially symmetrical parts joined together along a common plane. 25 In yet another aspect of the invention the disc is formed of two joined non symmetrical parts. In another aspect of the invention of the training sports ball for a predetermined sport that uses a sports ball shape that is substantially WO 2006/063391 PCT/AU2005/001879 4 spherical includes a seam shape on the substantially spherical outermost surface. A further aspect of the invention is a method of training a sports player 5 using a sports training ball according to one or more of the abovementioned aspects of the invention including the steps of: providing instructions to a user of the sports training ball to deliver the ball in accord with the rules of a predetermined sport; and providing instructions to the user to spin the sports ball in a 10 predetermined manner during the action of the delivery of the sports training ball. Throughout this specification unless the context requires otherwise, the words 'comprise' and 'include' and variations such as 'comprising' and 15 'including' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Specific embodiments of the invention will now be described in some 20 further detail with reference to and as illustrated in the accompanying figures. These embodiments are illustrative, and not meant to be restrictive of the scope of the invention. Suggestions and descriptions of other embodiments may be included within the scope of the invention but they may not be illustrated in the accompanying figures or alternatively features 25 of the invention may be shown in the figures but not described in the specification.

WO 2006/063391 PCT/AU2005/001879 5 The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge. 5 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a traditional cricket ball; Figure 2 depicts an over spin imparted on a ball; Figure 3 depicts a side spin imparted on a ball; Figure 4 depicts how drift is imparted on a ball; 10 Figure 5 depicts how off spin is imparted on a ball; Figure 6 depicts how leg spin is imparted on a ball; Figure 7 depicts a swing batting technique on a ball; Figure 8 depicts an embodiment of a practice sports ball; Figure 9 depicts the embodiment of Figure 8 being used to practice swing 15 bowling; Figure 10 depicts the embodiment of Figure 8 being used to practice spin bowling; Figure 11 depicts the grip used to put into effect a leg spin bowling action; Figure 12 depicts the grip used to put into effect a leg spin bowling action 20 from a different perspective to Figure 11; Figure 13 depicts the anticipated movement of the ball, resulting from a leg spin bowling action; Figure 14 depicts the grip on the ball to put into effect a leg spin bowling rotation on the ball; and 25 Figure 15 depicts the off side and on side of a batsman.

WO 2006/063391 PCT/AU2005/001879 6 DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION The embodiments of the invention described herein are but a few variations of the basic principle of using a disc shaped sports training ball, 5 where the term ball is used in its widest sense. That is, although a sports ball would typically refer to a spherical object used in a sporting activity, the ball of this invention is not the typical spherical shape but disc-like in shape. 10 When a disc-like shape is imparted with a spinning force about its circumference, the sports training ball of the invention will travel through the air and react to being put into contact with a substantially flat sports playing surface in a manner characteristic of a similarly sized diameter spherical ball of the particular sport being trained for, but there will be 15 differences that are not as great as to negate the action and reaction applied to the sports training ball by a person wishing to achieve the same action and reaction to a normal sports ball. Furthermore, the action and reaction of the sports training ball will be more readily apparent to the person being trained or using the sports training ball than if they had used a normal 20 sports ball. The helpful result is, that if spin is imparted correctly, it will be readily apparent because the disc shape will be visible or not visible as required according to the type of spin attempted to be imparted. The result of the 25 spinning effect will be more readily apparent to the trainer and user during the flight of the sports training ball.

WO 2006/063391 PCT/AU2005/001879 7 If however, spin is imparted incorrectly for the particular sport being trained for, the disc shape will be harder to distinguish or visible as required during the flight of the sports training ball. 5 Furthermore the reaction of the sports training ball to impact with the sporting surface will be, in the case of a correctly delivered ball, readily apparent and most likely in a way that is intended and expected and which will also be more readily apparent to the trainer and user. 10 However, if the spin imparted by the user is incorrect for the intended reaction once it impacts with the sports playing surface, then that will also be readily apparent. In most cases of the later circumstance, the substantially parallel sides of the sports training ball or the sharp corner of the junction of the side walls with the substantially spherical 15 circumferential surface will make the sports training ball veer wildly off its intended track. Thus, the primary purpose of the sports training ball is to provide visible feedback while training for a sport where it can be important to implement 20 spin on the ball for the purpose of either movement in the air and/or off the ground (as for example in the game of cricket). For example only, as the principles of the invention will have application to other sports balls, the sport of cricket is discussed in detail herein. Also 25 in this description the term batsman is used and is a term that applies to any person using a bat in the game of cricket. A cricket ball is a hard, solid ball typically having an interior of cork and may also be latex rubber or wool twine or combinations thereof and a WO 2006/063391 PCT/AU2005/001879 8 leather casing having a slightly raised sewn seam to join the two halves of the leather case about a circumference of the ball. For the game of cricket according to regulation set by the governing body, the ball must weigh between 5.5 and 5.75 ounces (155.9 and 163 grams) and measure between 5 8.8125 and 9 inches (224 and 229 millimetres) in circumference. Figure 1 depicts a standard cricket ball. Smaller weights and dimensions will apply to ladies and junior versions of a cricket ball. The following definitions are provided to merely assist the reader 10 unfamiliar with the game of cricket and are not meant to usurp the meaning of the defined term as would be understood by one skilled in the art. Definitions: 15 Seam: The seam 10 of the ball is where it appears that two half spheres are joined together via stitching, refer to Figure 1. The seam is created by stitching to join two concave hemispherical halves of the outer leather casing of the ball. Typically 60-80 stiches in each row are prominent along an equatorial join of the two half spheres. 20 Spin: Spin refers to the rotation imparted on the ball around an axis. Spin bowling: Sometimes known as slow bowling, is a technique used for bowling in the sport of cricket. Practitioners are known as spin bowlers. 25 Over spin: Over spin can be considered 'topspin' as that it refers to the spin that is imparted up the back and over the top of the ball (as depicted in Figure 2). The ball then loops in the air and drops faster than would be WO 2006/063391 PCT/AU2005/001879 9 the case of a ball with no imparted spin and then bounces high after contact with the playing surface. Side spin: Side spin refers to the spin that is imparted on the side of the ball 5 (either clockwise or anti-clockwise as depicted in Figure 3). When the ball hits the ground, it makes the ball turn (refer following) off the wicket. Turn: Turn refers to the deviation of the ball off the wicket when a bowler imparts spin on the ball. 10 Drift: Drift refers to the sideways movement of the ball in the air based on the amount and direction of spin imparted on the ball. Drift is a term used for spin bowling only. Drift, when achieved correctly, preferably occurs very late in its path of travel when the ball is close to the batsman. 15 Swing: Swing refers to the sideways movement of the ball in the air based on the angle of the seam and differences in air pressure produced by opposing sides of the ball. Swing is a term used for non-spin bowlers only. 20 On and off side: These terms are often used to describe the side of a batsman on which a particular action or result of an action takes place. Figure 15 illustrates the off and on side (also referred to as the leg side) as defined with respect to the batsman. 25 The main aim of spin bowling is to deceive the batsman, both in the air (by making the ball drift and drop quicker than would normally be the case) and off the wicket (by making the ball turn and bounce higher than would normally be expected).

WO 2006/063391 PCT/AU2005/001879 10 This is largely achieved by making the ball: . spin very quickly (i.e. high level of revolutions per minute) . have the axis of rotation horizontal . have a uniform direction of spin along the seam of the ball 5 . have a combination of 'over spin' and 'side spin'. Depending on wind conditions and wicket conditions, a good rule-of-thumb is to have an angle of spin, relative to its direction of travel of 450*. The speed the ball travels is not critical, and is significantly lower than for 10 fast bowling. A typical spin delivery has a speed in the range 70-90 km/h (45-55 m/h). Spin bowling is divided into four different categories, depending on the particular physical technique used. There is no overlap between the basic 15 categories of wrist spin and finger spin. . Off spin - Right-handed with finger spin technique. Off spin is a type of spin bowling in the sport of cricket which is bowled by an off spinner and refers to a right-handed spin bowler who uses their 20 fingers to spin the ball from a right-handed batsman's off side towards the on/leg side (that is in towards the right-handed batsman or away from a left-handed batsman). This contrasts with leg spin, in which the ball spins from on/leg to off and which is bowled with a very different action. 25 Off spinners rely to a great extent on varying the speed, pitch and flight of the cricket ball. * Leg spin - Right-handed with wrist spin technique.

WO 2006/063391 PCT/AU2005/001879 11 Leg spin is a type of spin bowling used in cricket. A leg spin bowler attempts to flick the ball with their wrist in the act of delivery so as to cause the ball to spin anti-clockwise. When the ball bounces, the spin causes the ball to deviate sharply from right to left (as seen by the bowler). 5 The description applies exclusively to right-handed bowlers spinning the ball in this manner - other forms of spin bowling are known as off spin, left-arm orthodox spin, and the very rare left-arm unorthodox spin where left-handed bowlers use an action that mirrors a leg spinner. The required rotation for leg-spin is depicted in Figure 6. 10 Leg spinners bowl the ball far slower than fast bowlers (70-90 kilometres per hour rather than the 140-odd kilometres per hour of good quality pace bowlers), and typically use variations of flight by sometimes looping the ball in the air somewhat, allowing the effects of any cross-breeze and the 15 aerodynamic effects of the spinning ball to cause the ball to dip and drift before bouncing and spinning (usually called "turning") sharply. While very difficult to bowl accurately, it is the most, effective form of spin bowling against right-handed batters as the spin takes the ball away from the batter rather than in towards them, which is much more difficult to 20 deal with. Good leg spin bowlers are also able to bowl deliveries that behave unexpectedly, including the googly, which turns the opposite way to a normal leg break, and the topspinner, which doesn't deviate significantly. 25 A few exceptional leg spinners also mastered the flipper, a delivery that like a topspinner goes straight on landing but travels quickly and barely bounces on landing, often dismissing batters leg before wicket or bowled. . Left-arm orthodox spin - Left-handed with finger spin technique.

WO 2006/063391 PCT/AU2005/001879 12 In the sport of cricket, left-arm orthodox spin is the equivalent of off spin bowling, but bowled with the left hand. As a result, the ball spins away from a right-handed batsman, like leg spin. It is usually considered to be harder for a right-handed batsman to play against than off spin, but easier 5 to bat against than leg spin due to the (generally) smaller repertoire of delivery types. Depending on technique, a spin bowler uses their wrist or finger motion to impart spin to the ball around a horizontal axis that is at an oblique angle 10 to the length of the pitch. This sort of spin means it is also possible for the Magnus effect to cause the ball to deviate sideways through the air, before it bounces. Such deviation is called drift. The combination of drift and spin can make the ball's trajectory complex, and with a change of direction at the bounce can make it difficult for the batsman to deal with. 15 The variety of trajectories achievable by a spin bowler can be difficult for inexperienced or poor batsmen to deal with, and most players consider them to be the most difficult style of bowler to bat against. 20 Spin bowlers are generally given the task of bowling with an old, worn cricket ball. A new cricket ball better suits the techniques of fast bowling than spin bowling, while a worn one grips the pitch better and achieves greater spin. Spin bowlers are also more effective later in a game, as the pitch dries up and begins to crack and crumble. This again provides more 25 purchase for the spinning ball and produces greater deviation. Seam bowling Seam bowling is also a technique used for bowling in the sport of cricket. Practitioners are known as seam bowlers. Seam bowling is generally classed WO 2006/063391 PCT/AU2005/001879 13 as a subtype of fast bowling, although the bowling speeds at which seam bowling can be a used medium-pace bowling. When considering the physics of seam bowling it is useful to recognise that 5 a cricket ball is not a perfect sphere. The seam joining the pieces of leather is circumferential and the stitching is noticeably raised. If the ball is bowled such that the seam hits the pitch when it bounces, this irregularity can cause the ball to deviate sideways in its path. 10 In order to achieve this effect, a seam bowler delivers the ball with the seam held upright, with rotation about a horizontal axis. This keeps the seam aligned vertically as it travels towards the batsman, making it likely that the ball will bounce with the seam on the pitch. 15 The direction and degree of deviation from a straight path are dependent on the small-scale alignment of the seam and any irregularities in the pitch surface. This means that deviation caused by seam is chaotic and unpredictable. 20 Often the deviation caused by the seam is not large enough to cause a batsman significant problems with playing the ball. Occasionally, however, the ball can deviate far enough to hit the edge of the cricket bat instead of the middle, producing a catch for nearby fielders. 25 Swing bowling Swing bowling is a further skill of bowlers. The essence of swing bowling is to get the cricket ball to deviate sideways as it moves through the air towards the batsman. This is largely achieved by: WO 2006/063391 PCT/AU2005/001879 14 . the raised seam of the cricket ball . imparting a small amount of spin down the back of the ball . have the axis of rotation horizontal . have a uniform direction of spin along the seam of the ball 5 - have the angle of the seam relative to its direction of travel of approximately 20 degrees . asymmetry in the ball caused by uneven wear of its surface. The asymmetry of the ball is encouraged by the constant polishing of one 10 side of the ball by members of the fielding team, while allowing the opposite side to deteriorate through wear and tear. Over time, this produces a marked difference in the aerodynamic properties of the two sides. 15 As a fast ball is bowled with the seam held vertically and rotation about a horizontal axis, there are two possible factors that can cause the ball to move through the air: . If the seam is aligned to point slightly to one side or the other, the slipstream of air moving over the raised seam causes an aerofoil 20 effect, pushing the ball to one side. . The flow of air over the two different sides of the ball causes differential pressure based on the surface qualities of the sides. This causes the ball to curve through the air towards the rougher side. 25 In combination, these two effects can produce considerable sideways movement of the ball through the air, known as swing.

WO 2006/063391 PCT/AU2005/001879 15 Note that swing of a cricket ball is not caused by the Magnus effect, which gives rise to a force perpendicular to the axis of rotation (in this case up or down). The swing of a cricket ball is parallel to the axis of its rotation. 5 Normal swing Typically, a swing bowler aligns the seam and the sides of the ball to reinforce the swing effect. This can be done in two ways: . Outswinger: By aligning the seam to the left and placing the roughened side of the ball on the left, the ball will swing to the left. 10 To a right-handed batsman, this results in the ball moving away to the off side while in flight, usually outwards from his body. . Inswinger: By aligning the seam to the right and placing the roughened side of the ball on the right, the ball will swing to the right. To a right-handed batsman, this results in the ball moving into 15 the on/leg side while in flight, usually inwards towards his body. The curvature of swing deliveries can make them difficult for a batsman to hit with their bat. Reverse swing 20 Normal swing occurs mostly when the ball is fairly new. As it wears more, the aerodynamics of the asymmetry change and it is more difficult to extract a large amount of swing. When the ball becomes very old - around 70 or more overs old - it can 25 begin to swing towards the polished side rather than the rough side. This is known as reverse swing. Reverse swing tends to be stronger than normal swing, and to occur late in the ball's trajectory. This gives it a very different character to normal WO 2006/063391 PCT/AU2005/001879 16 swing, and because batsmen experience it less often they generally find it much more difficult to defend against. The following discussion regarding the sports training ball uses the specific 5 example of such a ball for the purpose of assisting the training of a bowler in the game of cricket. A sports training ball according to the invention will preferably have the following characteristics. 10 It is a disc shaped device of the same diameter and circumference as a standard cricket ball for the class of player being trained. Thus, in the case of junior cricket, it would be the same size as a junior ball (refer to details provided earlier). 15 Its outer spherical circumferential surface material should preferably be leather with a slightly raised sewn seam. This however doesn't restrict its manufacture only to only using leather as the outer material. As with current cricket balls, imitation balls or composite balls are often produced 20 to reduce cost and increase longevity compared with the cost and durability of a leather cricket ball. Alternative materials for the manufacture of a sports training ball include rubber and plastic and combinations of those materials and others. The plastic version of the sports training ball could be injection moulded or even spin moulded. The 25 types of plastics that may suit are any of a class of plastics based on acrylonitrile-butadiene-styrene copolymers ABS and others as deemed suitable.

WO 2006/063391 PCT/AU2005/001879 17 The width of the circumferential surface should be at least, in a practical sense two if not three fingers width. However, in view of the uncertainty and lack of standards when it comes to what is a width of a finger, it is preferable only, that the width of the sports training ball be at least two 5 fifths of the diameter of the substantially spherical circumferential surface of the sports training ball. Clearly it is preferable for the bowler to be able to use all the required grips on the ball which in some cases requires the use of two or three fingers side by side positioned over or about the seam. Such a configuration of the sports training ball is necessary to allow the full 10 range of bowling grips to be used, otherwise the practice variations and types of bowlers that could use the sports training ball is restricted. The opposing side surfaces of the sports training ball can be of material or shaped surface (curved, undulating, roughened, etc) that causes 15 differential air pressures (when bowled) based on the surface properties of the sides. In normal use, the sides of the sports training ball should not regularly come into contact with the ground, thus, it would be hard to produce surfaces with different properties through use alone in a practice environment. It is for this reason that the manufacture of a sports training 20 ball can provide these differences in material and surface on one or both (each side may be different) opposed side surfaces and therefore reduce or eliminate the need for practitioners to artificially create those conditions on a sports training ball that does not have them. The provision of such features is not obligatory and is merely an option. 25 The weight of the sports training ball should be similar to that of the normal ball, inclusive of whether it is a junior or senior ball. Also preferably, along with the weight the distribution of the weight should be such that it does not adversely affect the spinning properties of the ball.

WO 2006/063391 PCT/AU2005/001879 18 That is, the density of the ball may need to be made consistent throughout or distributed in a manner that provides the closest match to a match ball's characteristics when being bowled. 5 In some circumstances, it may be beneficial to produce the sports training ball with slightly different characteristics from those listed above. Features such as the seam of the ball, the rigidness of the ball, the dimensions of the ball and the texture of the ball may all differ according to different circumstances. These circumstances may include different climates in 10 which the ball will be used, level of standard of the user, cost, age of participants, etc this being a non-exhaustive list. An embodiment of the sports training ball is depicted in Figure 8. The seam 81 is depicted pictorially on Figure 8 and also shown pictorially on 15 other figures, and may on the sports training ball include a raised area or multiple projections arranged to mimic the shape and configuration of a cricket ball seam. Variations of the seam configuration will be used to suit the particular sport being practiced. The outermost circumferential region is spherical and in the cricket ball embodiment the size of the spherical 20 shape conforms to that of an appropriate regulation cricket ball although in Figures 8a and 8b this region is shown as being cylindrical for clarity of illustration only. The sides 83 and 84 are substantially planar but this means that they may be slightly convex or concave and may have on at least one side roughening surface features such as projections (not shown). 25 The practice sports ball is able to assist in identifying whether all the correct attributes of 'swing' bowling and 'spin' bowling are achieved as it provides significantly increased visible feedback to both users and coaches in comparison to the use of a 'normal' cricket ball.

WO 2006/063391 PCT/AU2005/001879 19 The usage of the sports training ball should closely mimic that of the 'normal' cricket ball including grip and method of delivery. 5 Figure 9 depicts a pictorial representation of the sports training ball being used to practice swing bowling. Figure 10 depicts the sports training ball being used to practice spin bowling in all its variations as described herein and as may be developed 10 by training and instructional persons. Leg Spin Grip: The orthodox grip is two fingers up and two down, with the split between the second and third fingers, which are spread across the seam. The top 15 joints of the index and second fingers lie across the seam, the third finger is bent and along the seam. The thumb rests on the ball and does not contribute to the action imparted to the ball. Refer to Figures 11 and 12 for depictions of the grip used to effect a leg spin 20 bowling action and 13 for a depiction of the anticipated movement of the ball through the air and off the cricket pitch. Although the picture illustrates a conventional cricket ball, the same grip can be used on a sports training ball as described herein. 25 Off Spin Grip: The orthodox grip for the off spinner is a two finger grip, with the first joints of the index and middle fingers spread widely on the seam. Ideally the thumb should not apply any pressure onto the ball. Spin is imparted primarily through the index finger.

WO 2006/063391 PCT/AU2005/001879 20 Rotations are imparted by a turn of the wrist. The grip on the ball is depicted in Figure 14. Although the picture illustrates a conventional cricket ball, the same grip can be used on a sports training ball as described 5 herein. Visible Feedback When bowling the sports training ball, if spin is imparted on the ball correctly, due to its physical shape, the disc shape will be clearly visible 10 throughout its path in the air. Also clearly visible will be the disc's angle of trajectory, rotation, direction of spin and axis of rotation. In contrast, the flight path and look of the sports training ball by an incorrect application of spin will be clearly discernible by the trainer and the bowler because the disc like shape will not be clear as the sides of the sports training ball 15 wobble and gyrate in an unexpected manner. The sports training ball can be used in both skillpractising drills and in full, game-like practising situations. Some skill practising drills would include kneeling on the ground and spinning the ball with an underarm action in 20 order to see the direction and stability of the spin. This can also be done with a partner by using an underarm action while in the kneeling position. One could also underarm the ball to another participant while standing, in order to practice the correct wrist action. 25 In one example, the bowler grips the disc, and draws their bowling hand past their hips, keeping their palm facing a partner located opposite them. As their arm swings forward, they straighten their fingers and flick their WO 2006/063391 PCT/AU2005/001879 21 wrist so that their palm finishes facing down. Spin is imparted primarily through their third finger. In the case of Orthodox Spinners, it can also be thrown to a partner while 5 using the correct wrist action to produce the spin. Other Sports: For other sports (including golf), the weight, surface texture and circumference of the sports training ball should be a true or a close 10 representation of the sport ball it is relevant to. The sports training ball should also have similar flight and bounce characteristics to the sport ball it is representing. When that involves sports for different ages and levels, possibly different substances and sizes can be used in order to achieve this requirement. 15 Golf example In golf training for example, the user of the practice ball will place the disc of the sports training ball with a vertical orientation on the golf tee, wherein the substantially parallel sides have a vertical orientation with 20 respect to the ground and the plane of each side points in the direction the user wishes to hit the sports training ball. Once the sports training ball is struck the flight characteristics will show in what direction the line of force was when the club face imparted energy to 25 the sports training ball. For example if the ball travels in a straight line and the orientation of the sports training ball remains the same, the appropriate force was imparted to the sports training ball.

WO 2006/063391 PCT/AU2005/001879 22 When the user "slices" across the disc (or hooks), the disc will not travel in the desired direction as the direction of force imparted to the ball by the club face is not in line with the desired direction of the ball, therefore 5 providing immediate feedback to the golfer. Having the disc pointing in the direction they wish to hit before it is struck provides a very visual cue (or instruction) as to the direction the club face needs to travel when it impacts against the ball. 10 The golfing and cricket applications of the sports training ball are merely examples. It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular applications described. Neither is the 15 present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications within its scope.

Claims (16)

1. A sports training ball for a predetermined sport that uses a ball that is substantially spherical, the sports training ball characterised by having 5 an outer shape that has two substantially parallel side surfaces and a spherical circumferential surface.

2. A sports training ball according to claim 1 having the same weight as a predetermined sports ball. 10

3. A sports training ball according to claim 1 having planar side surfaces.

4. A sports training ball according to claim 1 having concave or convex 15 side surfaces or a combination thereof.

5. A sports training ball according to any preceding claim having a seam on the spherical circumferential surface. 20

6. A sports training ball according to any preceding claim wherein the density of the sports training ball varies from one part of the ball to another.

7. A sports training ball according to any preceding claim wherein the 25 sports training ball is rough on one side.

8. A sports training ball according to any preceding claim wherein the sports training ball is smooth on one side. WO 2006/063391 PCT/AU2005/001879 24

9. A sports training ball according to any preceding claim wherein the width of the sports training ball is at least two fifths of the diameter of the substantially spherical circumferential surface. 5

10. A method of forming a sports training ball for a predetermined sport that uses a sports ball shape that is substantially spherical consists of the following steps: removing two opposed portions of a substantially spherical sports ball used in the predetermined sport to form the outer shape of the sports 10 training ball into a disc having substantially parallel side surfaces and a spherical circumferential surface.

11. A method of forming a sports training ball according to claim 10 wherein the removal of opposed portions is from an inner form of a sports 15 ball and then the modified inner is covered by an outer material.

12. A method of forming sports training ball according to claim 11 wherein the outer material is leather. 20

13. A method of forming a sports training ball for a predetermined sport that uses a sports ball shape that is substantially spherical consists of the following steps: joining two parts to form a disc having two substantially parallel outer side surfaces with a spherical circumferential surface. 25

14. A method of forming a sports training ball according to claim 13 wherein said disc is formed of two substantially symmetrical parts joined together along a common plane. WO 2006/063391 PCT/AU2005/001879 25

15. A method of forming a sports training ball according to claim 13 wherein said disc is formed of two joined non-symmetrical parts.

16. A method of training a sports player using a sports training ball 5 according to one or more of the previous claims including the steps of: providing instructions to a user of the sports training ball to deliver the ball in accord with the rules of a predetermined sport; and providing instructions to the user to spin the sports ball in a predetermined manner during the action of the delivery of the sports 10 training ball.