Patent Publication Number: US-2013237347-A1

Title: Sports Training Apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Australian Provisional Patent Application Serial No. 2012900945 filed on Mar. 9, 2012. 
     FIELD OF THE INVENTION 
     The invention relates to a sports training apparatus. The invention also provides a sports training kit. 
     BACKGROUND TO THE INVENTION 
     Many types of sports training apparatus, including those for racquet sports such as tennis training apparatus, are directed towards providing repetitive action to permit a user repeatedly to perform certain strokes or movements. 
     It is desirable that a user or player not have to collect a ball after each strike. This has been achieved to some degree with various ball launchers that launch multiple balls. However, such launchers suffer from a number of disadvantages. 
     Launchers can be bulky and heavy, making transport and set up difficult. They usually require a power supply, which can be inconvenient where the training area is remote. The use of a launcher also requires that a large number of balls be supplied. Also, once all the balls have been launched, it is necessary to refill the launcher. This can be tedious and time confusing. 
     In addition to the above disadvantages, launchers tend to launch balls in a predictable pattern, which is different to the random nature of a game. As a result, a user can easily anticipate the flight of the ball. 
     SUMMARY OF THE INVENTION 
     The invention provides a sports training apparatus, which includes: a base for mounting onto a support; a rod that is attached to the base in a manner in which at least part of the rod can extend beyond the base so that when the base is mounted on the support, the rod extends above the support; an elastic cord that is attached to the rod at one end; and a ball that is attached to another end of the cord, the rod being positioned so that when the cord extends as a result of movement of the ball away from the support in one direction, the rod and the cord can cooperate to facilitate the return of the ball over the support in an opposite direction when the cord contracts. 
     The rod may be resilient so that it can bend in the direction of movement of the ball away from the support as the cord extends to help return the ball when the cord contracts and the rod straightens so that a user can strike the ball repeatedly. 
     It will be appreciated that the height of the rod above the support also helps to return the ball over the support. 
     The rod may be elongated and formed from a material that allows the rod to bend or flex when the cord is extended by the ball being struck and travelling over the support away from the rod 
     The rod may be pivotal or hinged relative to the base to pivot or swing between an operative position in which the rod extends above the support when the base is mounted on the support and an inoperative position in which the rod extends below the support to avoid obstructing the ball as it returns over the support. 
     The sports training apparatus may include a hinge or joint for attaching the rod to the base to provide pivotal or hinged movement of the rod between the operative and inoperative positions. 
     The joint may permit the rod to pivot or swing under gravity from the operative position to the inoperative position. Also, one of the joint and the base can incorporate or include a stop so that the rod stops at the operative position once it has moved away from the inoperative position under action of the ball being struck and subsequently moving over the support. Return of the ball and subsequent slackening of the cord causes the rod to swing back down, under gravity, to the inoperative position to facilitate movement of the ball back over the support without obstruction by the rod. 
     The rod may be attached to the joint in a manner in which detachment is facilitated. In one embodiment, the joint may include a tubular portion defining a passage for receiving the rod, and a grub screw, clamping device, or other securing mechanism for securing the rod in the passage in a manner which allows release and removal or adjustment of a length or height of the rod above the support. 
     The joint may be configured to provide two degrees of freedom of movement. Thus, the joint can be a universal joint, or can be a complete joint with two hinge zones or locations. It follows that the rod can also tilt from side-to-side to facilitate variance in the manner in which the ball travels. 
     The base may include a board. The board may have a mounting, clipping or fastening device for mounting the board onto the support. The device may permit removal and replacement of the board. 
     The stop may be a stopper that is interposed between the joint and an end of the board. The clipping or fastening device may be oriented so that when the board is mounted on the support, the joint and the stopper are positioned with the stopper above the joint. Thus, the stopper is in a position for stopping the rod when the rod pivots towards the operative position. The stopper may be formed from a resilient shock absorbing material such as rubber. 
     The stopper can be in the form of a number of different shapes. For example, the stopper can be cylindrical to present a circular stopping face. Where the joint is universal or complex, the stopper can extend across the board to accommodate pivotal and angular movement of the rod. 
     The board may be generally rectangular in shape and may define opposing laterally inwardly projecting recesses for winding the cord onto the board. It follows that the cord can be wound about the board to facilitate stowing of the apparatus. 
     The board may also define an aperture that is shaped and sized for receiving the ball in a friction fit to facilitate stowing of the apparatus. 
     The board may include a strap that is attached to the board for strapping an operatively lower end of the board to the support to stabilise the board, in use. 
     The cord may be of latex or rubber or of a material with similar properties to latex or rubber. The latex may be natural or synthetic. The cord may solid with a diameter of between 2 mm and 4 mm, for example, 3 mm. Instead, the cord may be tubular so that the cord has less mass than a solid cord of similar dimensions with similar elastic properties. In one example, an outer diameter of the cord may be between approximately 3 mm and 5 mm while an inner diameter of the cord may be between approximately 2 mm and 4 mm. Also, the cord may be between 3 m and 15 m in length. However, it will be appreciated that this length can vary depending on the application. 
     The cord may be attached to the rod with a swivel connector mounted on an end of the rod. This permits the cord to swivel with respect to the rod to avoid winding up and subsequent entanglement of the cord. 
     The cord may be attached to the rod in a releasable manner so that the cord can be replaced if necessary. For example, the cord can be tied to the swivel connector in a releasable manner. 
     The rod may be between about 40 cm and 70 cm long. For example, the rod may be between about 55 cm and 65 cm and in one embodiment about 58 cm. The rod may have a base diameter of between about 5 mm and 9 mm and a tip diameter of between about 1 mm and 5 mm. For example, the rod may have a base diameter of between about 6 mm and 8 mm, in one embodiment about 7 mm, and a tip diameter of between about 2 mm and 4 mm, in one embodiment about 3 mm. 
     Instead of being a fixed length, the rod may be telescopic so that the length can be adjusted, if necessary. 
     In addition, the rod and the hinge or joint may be configured so that the rod can also spin freely relative to the hinge or joint while being retained against linear movement. This can enhance movement of the cord over the net and can further inhibit entanglement. 
     The ball may be a tennis ball, in which case the clip may be configured for clipping onto an upper edge portion of a tennis net. The strap may include hook-and-loop formations, such as Velcro™, for securing the lower end of the board to the net. 
     The board may define an aperture to form a carry handle, and the strap may pass through the handle, in use, for securing the board to the net. 
     The invention extends to a sports training apparatus, which comprises a base for mounting onto a support; and a rod that is attached to the base in a manner in which at least part of the rod can extend beyond the base so that when the base is mounted on the support, the rod extends above the support, an elastic cord being capable of attachment to the rod at one end with the other end of the cord being connectable to a ball, the rod being positioned so that when a tension is set up in the cord as a result of movement of the ball away from the support in one direction, the rod and the cord can cooperate to facilitate the return of the ball over the support in an opposite direction when the cord contracts. 
     The sports training apparatus may include the cord, a connector being attached to said other end of the cord to permit a ball to be connected to the cord in a releasable manner. 
     The invention also provides a sports training kit, which includes: a racquet; and a sports training apparatus as described above. 
     The kit may include a package for packaging the racquet and the sports training apparatus. 
     The sports training apparatus may include any one or more of the options or features as herein defined, described, and illustrated. For example, a sports training apparatus of the invention may be provided with or without the cord and/or the ball. 
     The racquet may be a tennis racquet. 
     The base or board of the sports training apparatus may be shaped to correspond generally with a head of the racquet, so that the racquet and the sports training apparatus may be stored or carried together with the board within a rim of the racquet and overlying strings of the racquet. 
     The package may be a racquet cover. In that condition, the rod may be removed from the hinge and placed inside the racquet cover. 
     The invention also provides a method for facilitating return of a ball to a user for enabling a user to practice on their own with a net, the method including equipping a court or the like with a sports training apparatus as described above. 
     The sports training apparatus may include any one or more optional features as herein defined, described, and illustrated 
     A sports training apparatus, in accordance with the invention, may manifest itself in a variety of forms. It will be convenient hereinafter to describe embodiments of the invention in detail with reference to the accompanying drawings. The purpose of providing this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However, it is to be clearly understood that the specific nature of this detailed description does not supersede the generality of the preceding broad description. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a three-dimensional view of one embodiment of a sports training apparatus, in accordance with the invention. 
         FIG. 2A  shows a schematic side elevation view of the apparatus of  FIG. 1  in a mounted, pre-use or inoperative condition, illustrating a manner of movement of a rod of the apparatus. 
         FIG. 2B  shows a schematic side elevation view of the apparatus of  FIG. 1  in a mounted, operative condition, with a ball of the apparatus moving away from a user. 
         FIG. 2C  shows a schematic side elevation view of the sport training apparatus of  FIG. 1  in a mounted, operative condition, with a ball of the apparatus moving back towards or returning to a user. 
         FIG. 3  shows a three dimensional view of a kit, in accordance with the invention, that includes a racquet and another embodiment of a sports training apparatus, in accordance with the invention. 
         FIG. 4  shows an exploded three-dimensional view of the apparatus of  FIG. 3 . 
         FIG. 5  shows a three-dimensional view of the apparatus of  FIG. 3 . 
         FIG. 6  shows a side view of the apparatus of  FIG. 3 . 
         FIG. 7  shows a plan view of the apparatus of  FIG. 3 . 
         FIG. 8  shows a three-dimensional view, from behind, of the apparatus of  FIG. 3 , with one example of a base. 
         FIG. 9  shows a three-dimensional view, from behind, of the apparatus of  FIG. 3 , with another example of a base. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the drawings, reference numeral  10  generally indicates a sports training apparatus, in accordance with the invention. In this embodiment, the sports training apparatus is in the form of a training apparatus for ball sports utilising a net. One example of an application is tennis training. 
     The training apparatus  10  includes a base  12  for mounting onto a support, in this example, an upper edge portion of a net  14  ( FIGS. 2A to 2C ) such as a tennis court net. The training apparatus  10  also includes a rod  16  that is attached to the base  12  in a manner in which at least part of the rod  16  can extend beyond the base  12  so that when the base  12  is mounted on the net  14 , the rod  16  can extend above the net  14  as shown in  FIG. 2B . 
     An elastic cord  18  is attached to the rod  16  at one end. A ball  20  is attached to the other end of the cord  18 . A loop  19  ( FIGS. 3 and 5 ) is attached to the ball  20 . A connector  21 , such as a clip or swivel, interconnects the cord  18  and the ball  20 . The connector  21  permits the ball  20  to pivot or spin relative to the cord  18  to help prevent winding up and entanglement of the cord  18 . 
     The rod  16  is positioned so that when the cord  18  extends or stretches as a result of movement of the ball  20  away from the net  14  in one direction ( FIG. 2B ), the rod  16  and the cord  18  can cooperate to facilitate the return of the ball  20  over the net  14  in an opposite direction ( FIG. 2C ) when the cord contracts. 
     The base  12  is in the form of a board that is generally rectangular in shape. The board  12  defines opposing laterally inwardly projecting recesses  22  for winding the cord  18  onto the board  12 . It follows that the cord  18  can be wound about the board  12  to facilitate stowing of the apparatus  10 . 
     The board  12  also defines an aperture  24  that is generally circular and that is shaped and sized for receiving the tennis ball  20  in a friction fit, also to facilitate stowing of the apparatus  10 . A groove  26  extends from the circular aperture  24  to receive the portion of the cord  18  adjacent the tennis ball  20 . 
     The board  12  has a length of between about 300 mm and 400 mm, for example, about 360 mm and a lateral width of between about 200 mm and 300 mm, for example about 240 mm. 
     The board  12  can be of a number of different materials. For example, the board  12  can be of wood, moulded plastics material or a composite, such as fibreglass composite or carbon fibre composite. 
     The board  12  also defines a generally T-shaped aperture  28  so as to form a carry handle  30 . In use, a strap  32  is passed through the aperture  28  for securing an operatively lower end of the board  12  to the tennis net  14 , to resist tilting of the board  12 , in use. The strap  32  includes hook-and-loop formations, such as Velcro™, for securing the lower end of the board  12  to the tennis net  14 . The width of the T-shaped aperture  28  is about 2.5 cm. 
     The board  12  includes a clipping device  34  for temporarily mounting the board  12  onto an upper edge of the net  14 , as shown in  FIGS. 2A to 2C . 
     The apparatus  10  includes a joint  38  for attaching the rod  16  to the board  12 . The joint  38  enables the rod  16  to pivot or hinge between an operative position in which the rod  16  extends above the net  14  when the board  12  is mounted on the net  14  and an inoperative position in which the rod  16  extends below the support to avoid obstructing the ball  20  as it returns back over the net  14 . The pivotal movement of the rod  16  is indicated by the arrow  17  in  FIGS. 2A to 2C . 
     The joint  38  include a passage defined by a retaining tube  40  for receiving the rod  16 , and a grub screw  37  or similar threaded through an opening  43  for bearing against and securing the rod  16  in the tube  40 . That way, the rod  16  is detachable so that release and removal of the rod  16  is facilitated. Furthermore, an effective height of the rod  16  above the net  14  can be adjusted by releasing the screw  37  and sliding the rod  16  in the tube  40 . It will be appreciated that the height of the rod  16  can be adjusted in other ways, for example, by providing the rod  16  as a telescopic rod. Adjustment of the height allows tuning of the apparatus  10  to suit the style of the user and the required characteristics of the ball flight. 
     The joint  38  includes a post  39  mounted in and extending from the board  12 . The retaining tube  40  is mounted on the post  39  with a swivel or pivot mechanism  41 . 
     In a shortened condition of the rod  16 , a leg  29  of the T-shaped aperture  28  accommodates a lower portion of the rod  16  as it pivots downwardly. The leg  29  has a width of between about 20 mm and 30 mm, for example about 25 mm. A length of the aperture  28  is between about 150 mm and 250 mm, for example about 200 mm. 
     A stop in the form of a stopper  35  is mounted on the board  12 . The stopper  35  is interposed between the joint  38  and an operative upper end  45  of the board  12 . The clipping device  34  is oriented so that when the board  12  is mounted on the net  14 , the joint  38  and the stopper  35  are positioned on a longitudinal axis of the board  12  with the stopper  35  above the joint  38 . Thus, the stopper  35  is in a position for stopping the rod  16  when the rod  16  pivots or swivels towards its upright position. The stopper  35  is generally cylindrical and is formed from a resilient shock absorbing material such as rubber. 
     The joint  38  is spaced from the stopper  35  a distance of between about 80 mm and 150 mm, for example about 110 mm. It will be appreciated that the distance between the joint  38  and the stopper  35  is selected to make the best use of the characteristics of the rod  16  to achieve the necessary return force applied to the ball  20  together with the cord  18 . It follows that other distances between the joint  38  and the stopper  35  can also be applicable. 
     In particular, the joint  38  and the stopper  35  are spaced so that, together with the rod  16 , the ball  20  can exert a force on the rod  16  to generate a whiplash effect as it flips upwardly, strikes the stopper and flexes to return the ball  20 . 
     Furthermore, the height of the rod  16  helps to ensure that the ball  20  can clear the net  14  when returning after being struck correctly. As the ball  20  returns, the cord  18  slackens and the rod  16  flips downwardly as a result of at least its centre of gravity with assistance from the recoil off the stopper  35 . This allows the ball  20  to pass back over the net  14  without being obstructed by the rod  16 . 
     The cord  18  is formed from latex or rubber, and is solid. The cord  18  has a diameter of between about 2 mm and 4 mm, for example about 3 mm. Instead, the cord  18  can be tubular so that the cord  18  has less mass than a solid cord of similar dimensions with similar elastic properties. In this example, an outer diameter of the cord is approximately 3 mm to 5 mm while an inner diameter of the cord  18  is approximately 2 mm to 4 mm. Also, the cord is about 4 m to 15 m long. However, it will be appreciated that this length can vary depending on the application. 
     Broadly, the rod  16  is capable of exerting a pull force on the cord  18  when the cord  18  is tightened or tensioned as a result of extension or stretching by the tennis ball  20  when it is struck over the tennis net  14 . The rod  16  is configured to cooperate with the cord  18  to return the tennis ball  20  back over the tennis net  14 , as is explained in more detail below. 
     The rod  16  is elongated and formed from a suitable material, such as graphite, carbon fibre or fibre glass that allows the rod  16  to bend against a bias of its original shape or flex resiliently when the cord  18  is tightened by the ball  20  being struck over the tennis net  14  away from the rod  16 . An example of a suitable configuration of the rod  16  could be similar to that used for fishing rods. The rod  16  can thus be of a fibre glass composite. Other examples of suitable material include plastics materials and metal, such as spring steel and aluminium or aluminium alloy. It will be appreciated that the cross sectional dimensions of the rod will vary depending on the type of material being used. 
     The rod  16  has a length of between about 400 mm and 700 mm, for example about 580 mm, and tapers from an operative lower end to an operative upper end. When of a glass fibre composite, the rod  16  has a base diameter of between about 5 mm and 9 mm, for example about 7 mm, and a tip diameter of between about 1 mm and 5 mm, for example about 3 mm. 
     The rod  16  also includes a swivel or pivot mount  64  at its end and a loop  66  for attaching the cord  18  to the swivel  64 . The swivel  64  allows the loop  66  to spin. That accommodates spinning of the ball  20  at least to some extent which obviates undue twisting of the cord  18  and resultant entanglement. It will be appreciated that the cord  18  can also be detached from the mount  64 , for replacement, if necessary. For example, the cord  18  can be tied or untied to or from the mount  64 . It follows that it is envisaged that the apparatus  10  can be supplied with or without the cord  18  and/or the ball  20 . 
     Referring to  FIG. 3 , a kit  50  is shown that includes a tennis racket  52  and another embodiment of a training apparatus  54 . The kit  50  also includes a package (not shown) in the form of a racquet cover for packaging the racquet  52  and the tennis training apparatus  50 . With reference to  FIGS. 1 and 2 , like reference numerals refer to like parts, unless otherwise specified. 
     The training apparatus  54  has a board  58  shaped to correspond generally with a head of the racquet  52 , so that the racquet  52  and the tennis training apparatus  54  can be stowed generally coincident with each other in the racquet cover. The board  58  is dimensioned to be received within a rim  59  of the racquet  52 . 
     The cover can define an aperture so that the joint  38  can project through the aperture when the tennis training apparatus  54  is packaged with the racquet in the racquet cover. The rod  16  can also be packaged by positioning it along a length of the racquet  52  within the racquet cover. 
     Further, instead of a circular aperture for holding the tennis ball  20 , the board  58  of the tennis training apparatus  54  defines a widened aperture portion, at  62 , for receiving the tennis ball  20  in a frictional fit. 
       FIGS. 4 to 9  show the apparatus  54  in further detail. 
     The clipping device or clip  34  is of a resiliently flexible material, such as a plastics material or sprung steel, that is formed to define a rear flap  68  and a front lip  70  so that the clip  34  is received on the end  45  of the board  58 . The end  45  has a recessed portion  72  to accommodate the clip  34 . 
     The recessed portion  72  defines a hole  74  that is aligned with an opening  76  in the lip  70  when the lip  70  is fastened to the board  58  with fasteners  78 . 
     The board  58  defines a series of locating formations  80  about a periphery of the hole  74 . The stopper  35  has a base  82  that defines a series of complementary locating formations  84  that engage the formations  80  as the base  82  is inserted through the opening  76  and into the hole  74 . 
     The base  82  also defines a retaining formation  86  to retain the base  82  in the hole  74 . A suitable fastener  88  is used to secure the base  82  in the hole  74 . 
     A stop member  90  of rubber, elastomeric, or similar material is attached to the base  82 . 
     The post  39  of the joint  38  has a pair of arms  92  extending from a base  96 . The board  58  defines a socket  94  in which the base  96  is received. The socket  94  and the base  96  define complementary nesting formations  98  to secure the base  96  rotationally with respect to the board  58 . A fastener  100 , received through a floor  102  of the socket  94  is threaded into the base  96  to secure the base  96  in the socket  94 . 
     The arms  92  define aligned, inwardly extending pivot formations  104 . A carrier  106  extends from the retaining tube  40 . The carrier  106  defines an aperture  108 . Each of the pivot formations  104  are received in the aperture  108 . The post  39  is oriented so that pivotal movement of the retaining tube  40  is in a plane that substantially longitudinally bisects the board  12 . 
     A tubular socket  114  extends from the retaining tube  40 . The socket  114  has a hexagonal internal profile to receive a threaded nut  116  so that the nut  116  is locked against rotation. A locking screw  118  has a threaded shank  120  and a head  122  so that the shank  120  can be threaded through the nut  116  to bear against the rod  16 . Thus, when the locking screw  118  is loosened, the rod  16  can be shifted into a desired position, or removed. When the rod  16  is in a desired position, the locking screw  118  can be rotated so that the shank  120  bears against the rod  16  to secure the rod  16  in position. 
     A cord winding groove  124  extends from the aperture  28  to one of the recesses  22  to facilitate winding the cord  18  about the board  58  for storage. 
     As can be seen in  FIG. 5 , the strap  32  has one part  126  of a hook and loop fastening material arranged along its length. Another part  128  of the hook and loop fastening material is arranged on part of an inner surface of the board  58  bounding the aperture  28 . Thus, the strap  32  can be used to fasten the board  58  to the net by attaching one end of the strap  32  to the inner surface, threading the strap through the net and fastening the other end of the strap  32  also to the inner surface. 
       FIGS. 6 and 7  show, approximately, the relative dimensions and orientation of the components of the apparatus  54 . In particular, selection of the dimensions A, B and C has a material effect on the manner in which the apparatus operates. 
     Dimension A is a height or length of the stopper  35 . Dimension B is a distance of a centre-line  130  of the tube  40  from a face  132  of the board  58 . Dimension C is a distance from a pivotal axis  134  of the rod  16  to the stopper  35  in a plane of rotation of the rod  16 . 
     In this embodiment, A is between approximately 30 mm and 40 mm, for example 33 mm to 37 mm. B is between approximately 35 mm and 50 mm, for example, 35 mm and 40 mm. C is between approximately 90 mm and 100 mm. In one embodiment, the dimensions A and B are selected so that when the rod  16  bears against the stopper  35 , a longitudinal axis of the rod  16  diverges from the board  58  towards the end  45  at an angle of between 0 degrees and 10 degrees, for example, 5 degrees. Furthermore, C is selected to achieve a suitable whiplash or dynamic flex of the rod  16  when it strikes the stopper  35 . 
       FIGS. 8 and 9  show two different examples of a structure of the board  58 . In  FIG. 8 , the board  58  is moulded with ribbing to provide a board  58  with a structural rigidity similar to that of a solid board, without the weight of a solid board. In  FIG. 9 , the board  58  can either be solid, or can be the board of  FIG. 8  with a backing plate  112  for aesthetic purposes. 
     In use, when a user wishes to train, the user unwinds the cord  18  from the board  12 , and mounts the board  12  onto an upper edge portion of the tennis net  14  using the clip  34  and the strap  32  ( FIGS. 2A to 2C ). 
     At rest, the rod  18  is positioned as shown by  16 . 1  in  FIG. 2A . When a user strikes the tennis ball  20  over the tennis net  14 , and with sufficient force, the tennis ball  20  causes the cord  18  to tighten which in turn pulls the rod  16  which then hinges into its upright position. The start of that movement is shown in  FIG. 2A  by  16 . 2  as the rod  16  moves into the position shown in  FIG. 2B . 
     When the rod  16  reaches its upright position, it bears against the stopper  35 , and further tension from the cord  18  causes the rod  16  to bend away from its original shape, as shown in  FIG. 2B , while the cord  18  stretches. 
     When the inertia of the tennis ball  20  depletes under influence of the elastic cord  18 , the rod  16  returns to its original shape. As a result, the rod  16  pulls the cord  18  and thus the ball  20 . This facilitates return of the tennis ball  20  over the tennis net, in a motion similar to a whiplash as shown in  FIG. 2C . 
     The return of the tennis ball  20  enables a user to strike the tennis ball  20  repeatedly with the rod  16  moving as indicated by arrow  17 . 
     Furthermore, the apparatus permits the ball to bounce on the other side of the net, before returning to the user. This allows the user to determine whether or not he or she has accuracy when playing. This is an aspect which cannot be achieved when a user simply uses a wall against which to train. 
     It is to be appreciated that the selection of relative dimensions, weights and materials determines the operational characteristics of the apparatus  10 ,  54 . 
     For example, the average height of a tennis net is between about 90 and 94 cm, in practice. The length of the rod  16  is selected so that return of the ball  20  over the net is facilitated. As described above, there is an angle between the rod  16  and the board  58  when the rod  16  strikes the stopper  35 . That angle is selected so that, when the cord  18  slackens, the rod  16  drops with gravity immediately, allowing the ball  20  to pass back over the net  14  without striking the rod  16 . 
     In addition, in one embodiment, the total weight of the rod  16  and the swivel  64  is selected to be about 8% to 12%, for example 10%, lighter than the ball  16 . That, together with the angle described above, helps to allow the rod  16  to drop away in a sufficiently short time to avoid obstructing the ball  16 . 
     In one embodiment, the weight of the swivel  64  is greater than that of the rod  16 . For example, the swivel is between about 4 and 6 grams, for example, 5 grams, and the weight of the rod  16  is between about 1 and 3 grams lighter. Thus, the weight of the swivel  64  together with the angle of the rod  16  relative to the board  12 ,  58 , as described above, helps the rod  16  to drop out of the way of the returning ball  20 . In that embodiment, the ball  20  is between about 60 and 70 grams, for example about  66  grams, and the cord  16  is selected to have a weight of between about 10 and 20 grams, for example about 16 grams. 
     It will be appreciated that the relatively high weight of the ball  20  compared to the cord  18  and the rod  16  allow the ball  20  to travel in a natural manner back and forth over the net. Also, the relative dimensions, weights and materials selected allow the rod  16  to swing back and forth in a manner which is consistent and smooth, in a pendulum-type motion, allowing the player to develop a rhythm while still facing ball returns that are more realistic than those from a wall or a machine that launches tennis balls. 
     It will be appreciated that players of different heights will have different stroke requirements. As described above, an extent to which the rod  16  extends above the board  12 ,  58  is adjustable. This adjustability can be used to tune the apparatus  10 ,  54  to suit the player&#39;s height. 
     The ball  20  can be a standard tennis ball or it can be a high-bounce tennis ball. Alternatively, the ball  20  can be configured for attachment to the cord  18 , while being provided with characteristics similar to those of a standard tennis ball, such as weight and bounce. For example, the connector  21  can be releasable, allowing the tennis ball to be connectable to the cord and to be changed if necessary. It will be appreciated that any other means can be provided to allow the ball  20  to be connectable and changed, if necessary. It follows that both the cord  18  and the ball  20  can be replaced, if necessary. 
     The ball  20  can be attached to the cord  18  or the loop  19  in any one of a number of conventional ways which are known in the art. For example, the cord  18  or the loop  19  can be attached to a plug located in the ball  20 . The ball  20  can then be sealed, if necessary, to maintain pressure. 
     At present, it is possible to use machines that project tennis balls. However, such machines can be predictable, allowing the user to be lulled into a groove. The apparatus  10  incorporates a level of unpredictability, particularly after the ball bounces. The reason is that it is difficult to assess how the ball will return over the net and from what direction. This enhances the training experience. 
     Throughout the specification, including the claims, where the context permits, the term “comprising” and variants thereof such as “comprise” or “comprises” are to be interpreted as including the stated integer or integers without necessarily excluding any other integers. 
     It is to be understood that the terminology employed above is for the purpose of description and should not be regarded as limiting. The described embodiments are intended to be illustrative of the invention, without limiting the scope thereof. The invention is capable of being practiced with various modifications and additions as will readily occur to those skilled in the art. 
     The above description describes embodiments of the sports training apparatus defined in the claims. As such, the claims are intended to cover variations, modifications or enhancements of these embodiments that could become apparent to a person of ordinary skill in the art. It follows that the language used in the above description of the drawings should not be regarded as an indication that any material described above is essential to the working of the sports training apparatus defined in the claims, unless the above description clearly indicates otherwise. 
     When any number or range is described herein, that number or range is approximate. The ranges of values described are intended to cover each separate value falling within the range as if it were individually described.