Abstract:
The present invention discloses an exercise device wherein a user exercises the abdominal muscles and/upper body strength training by throwing a ball into a ball shoot or against a rebound surface. The user places back on a horizontal fixed back rest portion and buttocks on a pivotal seat and feet on an adjustable device provided for securing the feet. Springs provides shock dissipation while the user catches ball in a downward position. The user throws ball in an upward movement into a ball shoot retrieving ball located at bottom ball ramp.

Description:
[0001]     This is a continuation-in-part of U.S. patent application Ser. No. 11/338,567 filed Jan. 24, 2006, which claims domestic priority from U.S. Provisional Patent Application No. 60/647,861 filed Jan. 27, 2005, which are both incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a method and apparatus for strength training the upper body of a user, particularly the abdominal region, and more particularly to a method and apparatus which utilizes ball throwing and retrieving repetition to effect such strengthening of the abdominal and upper body muscles.  
         [0003]     An apparatus has been previously suggested in U.S. Pat. Ser. No. 6,280,367 issued to Arsenault on Aug. 28, 2001, incorporated herein by reference for details relating to the general. construction and functionality of an apparatus suitable for use in deflecting a ball thrown by a seated user in a direction back to the user, in which, as disclosed therein, a user exercises the abdominal muscles by throwing a ball against a net system. As described therein, the user places his buttocks and feet on a stationary platform (seat), and his head and back on a pivotable platform (backrest) which pivots about a hinge, spring biased in a raised position relative to the stationary platform. The spring provides lift assistance when the user throws the ball and shock dissipation when the user catches the ball. Foot straps are provided for securing the feet of the user. Nets are mounted on supports, which are vertically adjustable. When used as intended, the user lies on his back upon the base platform with his feet secured within the foot straps located in the proximity of the deflection net. The user&#39;s feet and buttocks reside on the stationary portion of the base platform while his back and head are supported by the pivoting backrest which is at approximately a 45 degree angle to the floor and stationary portion. The user begins the exercise by holding a ball and leaning back against the pivoting backrest to provide tension on the spring mechanism so he is propelled forward when he begins the sit-up. As the user is moving upward he throws the ball towards one of the deflection nets (i.e., center, right or left) depending upon which abdominal muscle group is selected to be worked.  
         [0004]     In accordance with the disclosure of the aforementioned prior art reference, the user attempts to time the throw so that the rebounding ball can be caught as he is heading back down to the reclined position where the tension spring provides resistance to dissipate impact and then reverses momentum to provide upward impetus for the next throw. While effective if performed properly, such timing may be difficult to achieve in practice for the novice or for individuals not in possession of sufficient muscle strength or coordination skills.  
         [0005]     Therefore, it would be desirable to provide an apparatus which facilitates practicing a method in which a ball is repeatedly thrown and retrieved by a user for purposes of upper body strength training with particular emphasis on the abdominal muscle groups, and which is readily implemented by even the most inexperienced of individuals.  
         [0006]     Accordingly, it is an object of the invention to provide a method and apparatus which overcomes the drawbacks of the prior art. It is a further object of the invention to provide a method and apparatus which allows a user to effectively and reliably strengthen many of the muscles of the upper body, particularly including the abdominal region, in a manner that is easy to implement even by the most inexperienced novice.  
       DESCRIPTION OF THE PRIOR ART  
       [0007]     Inventor: Arsenault; Christopher (P.O. Box 1724, Port Washington, N.Y. 11050) U.S. Pat. No. 6,280,367, Filed: Mar. 20, 2000  
         [0008]     A ball return apparatus for exercising abdominal muscles, more specifically, a ball return apparatus with a pivoting bi-sectional spring loaded base platform to help propel the user from a reclined position to a sitting position as he throws a weighted ball towards an elevated ball deflection net that is connected to the stationary portion of a base platform by means of a releasable high-tension mechanical stabilizing spring. A similar spring connects the stationary and pivoting portions of the base platform to provide lift when the user is on the upswing and shock dissipation when reclining. The present invention incorporates skill and gamesmanship into abdominal exercises so as to provide fun and interesting way for the user to get a complete abdominal workout.  
         [0009]     There are other ball return devices designed for returning balls while exercising. Typical of these is U.S. Pat. No. 5,039,109 issued to Kenneth J. Mahoney et al. on Aug. 13,1991.  
         [0010]     Another patent was issued to Andrew Caruso on Feb. 15, 1994 as U.S. Pat. No. 5,286,020. Yet another U.S. Pat. No. 5,580,048 was issued to Kerry D. Mullen et al. on Dec. 3, 1996. Another was issued on Mar. 25, 1997 to Hua-Lu Hsiang as U.S. Pat. No. 5,613,922 and still yet another was issued to Ronald A. Anderson et al. on Jun. 30, 1998 as U.S. Pat. No. 5,772,537.  
         [0011]     U.S. Pat. No. 5,039,109  
         [0012]     Inventor: Kenneth J. Mahoney et al.  
         [0013]     Issued: Aug. 13, 1991  
         [0014]     The portable mounting stand apparatus of this invention is adapted to receive a ball return apparatus for the like thereon and provide means for ease of movement from a portable transport condition to a rigid usage condition. The portable mounting stand apparatus includes a main support base assembly; a forward base support assembly secured to a forward portion of the main support base assembly; and a rearward base support assembly connected to a rear portion of the main support base assembly. The forward and rearward base support assemblies are each provided with support wheel assemblies to contact a support surface for ease of mobility in the transport position. The rearward base includes a pivotal stationary support assembly having a pivotable stand assembly which is selectively actuated to move support leg assemblies into and out of contact with the support surface. When in the rigid usage condition, the pivotable stationary support assembly acts to elevate the rearward support wheel assemblies out of contact with the support surface so as to present a rigid nonmoving structure for the use of the ball return apparatus, for example, on a basketball court in a basketball practice drill session.  
         [0015]     U.S. Pat. No. 5,580,048  
         [0016]     Inventor. Kerry D. Mullen et al.  
         [0017]     Issued: Dec. 3, 1996  
         [0018]     A modular return apparatus for reflecting back an object such as a ball or a puck when struck by the ball or puck traveling on a playing surface, for use in returning the ball or puck to the player for another shot and in training the player to shoot the ball or puck accurately and anticipate the anode of reflection and velocity of the puck or ball comprises an elongated reflecting bumper a pair of supports for the reflecting bumper, and a rod for connecting the supports to each other and preventing their relative motion. A net may be attached to the return apparatus to catch the puck.  
         [0019]     U.S. Pat. No. 5,613,922  
         [0020]     Inventor: Hua-Lu Hsiang  
         [0021]     Issued: Mar. 25, 1997  
         [0022]     A multipurpose athletic training apparatus including a trampoline, two fastening devices for fastening the trampoline to the stands, the fastening devices being adjustable to fix the trampoline to between a horizontal position in which the trampoline is used as a table, and a tilted position in which the trampoline is used as a rebound apparatus for rebounding balls thrown against it, a handrail for fastening to the stands at the top, and two net posts for fastening to the stands for stretching the net for the game of badminton.  
         [0023]     U.S. Pat. No. 5,772,537  
         [0024]     Inventor. Ronald A. Anderson et al.  
         [0025]     Issued: Jun. 30, 1998  
         [0026]     A ball return device that enables a user to quickly and easily adjust the force with which a ball thrown into the device is returned. The ball return device includes a frame constructed from sections of plastic tubing joined by 90-degree elbows, forming a base and an elevatable portion. The elevatable portion of the frame is pivotally mounted to the base and adjustably positioned at a desired angle relative to the generally horizontal base by a pair of support members. The angle of the elevatable portion of the frame to the base determines the direction in which the ball is returned relative to a given incident path. The support members extend between the base and the elevatable portion of the frame, and each includes a smaller diameter tube slidably fitted into a larger diameter tube and selectively fixed at one of a plurality of preset lengths by a pin that passes through orifices formed in the two tubes. In one referred form of the invention, a net having hexagonal openings is suspended within the elevatable portion of the frame.  
         [0027]     Another simple yet effective device that has been employed for decades in rehabilitation and more recently in general abdominal and core strength training is the stability ball. A stability ball is a flexible inflated ball, typically 55-65 cm, adapted to support some or all of the weight of a user during an exercise. Because the user is not only performing the exercise (e.g., a pushup or a leg lift) but also trying not to roll off of the ball and onto the floor, the user must engage his abdominal muscles to maintain proper balance in addition to whatever other muscles are being used during the exercise itself. As a result, stability ball training is very popular and effective. Alternative unstable and meta-stable exercise devices similar to the stability ball include a stability hemisphere described in U.S. Pat. Nos. 6,422,982 and 6,575,885 to Weck et al. and commercially made by BOSU Fitness, LLC of Canton, Ohio, as well as a platform and roller type device on which the user must balance.  
         [0028]     As popular as stability training may be, it is difficult to incorporate it simultaneously with the use of typical exercise devices with pulleys and cables in which the user pulls or pushes one moving part with respect to another part while standing or sitting down (e.g., a lat pull down machine or a seated row machine). It would be desirable to be able to incorporate stability training into the use of exercise devices such as these and even devices such as that described in the Arsenault patent mentioned above and the co-pending application herewith. While one could attempt to bring a stability ball over to such an exercise device, often a seat or stand of the exercise device is in the way, or else the stability ball provided insufficient stability for use as a user support by itself during use of the exercise device.  
       SUMMARY OF THE INVENTION  
       [0029]     In accordance with these and other objects of the invention, there is provided a method and apparatus in accordance with which, a user wishing to increase upper body strength repeatedly throws and retrieves one or more balls in repetitive sequence while altering a body posture. A ball held by the user is thrown while a torso of the user is flexed at the waist from a reclined position to a sitting position. A normal trajectory of the thrown ball is altered by suitable means to a redirected trajectory which returns the ball to a suitable position for retrieval by the user. The nature (speed, etc) and path of the redirected trajectory is advantageously selectable by alteration of physical characteristics of the apparatus according to the invention, such that a degree of difficulty in the retrieval process can be selected dependant upon the experience and desires of the user. As used herein, the tern “trajectory” is defined as broadly embracing any path (locus) of travel of an object in motion, and includes objects in contact with a physical contact surface or guide-way, as well as freely flying objects traveling through open space acted upon by the influence of gravity.  
         [0030]     In accordance with an embodiment of the invention, an apparatus includes a hinged seat, biased in a seat back upright (or partially upright) position on which the user sits such that a reclined and sitting posture can be assumed during performance of the intended exercise described below herein. A foot restraint is advantageously provided suitably located to facilitate the sitting up process for the user. A ball return guide is positioned in front of the seated user, and includes a structural configuration which redirects a normal trajectory of the ball when thrown into the ball return guide, causing the ball to instead assume a redirected trajectory along which the ball travels to a location below a position of entry when thrown, for subsequent retrieval by the user.  
         [0031]     In accordance with an advantageous embodiment, the ball return guide is configured as an arcuate track or channel presenting a continuously curved back surface extending from a top end to a bottom end, such that when the ball is thrown into the top end (upper portion) of the arcuate track the ball is roughly guided by the curvature of the back surface and is directed to the bottom end (lower portion) where it is retrieved. The arcuate track (channel) advantageously includes enclosed sides to prevent the ball from jumping out laterally while, following the back curvature. Still more advantageously, the sides are wider apart at the top end of the channel to allow for a greater margin of error in aiming when the ball is thrown by the user.  
         [0032]     In a particularly advantageous embodiment, an apparatus as described generally above optionally includes a structural adaptation allowing the user to select two modes of operation, each of the modes redirecting the ball in a particular manner different from the other. For example, the user can operate the apparatus in the manner described above, wherein the ball in thrown into upper portion of the channel and returned at a lower portion where the user retrieves it. Alternatively, a more advanced user can optionally select a mode whereby the ball is rebounded directly back to the user off of a suitable rebound surface, such as a hard or elastically tensioned flat and widened member. To achieve these objects, the apparatus advantageously includes a rebound member presenting a rebound surface against which the ball can be thrown, which can be alternately positioned between a position blocking the opening at the upper portion of the channel and another position in which the rebound member does not obstruct the ball reception opening in the upper “portion of the channel in the ball return guide.  
         [0033]     A further option includes a structural feature permitting a third mode of exercise, and in which a baffle is suitably positioned inside the channel of the ball return guide below the upper portion thereof through which the ball is thrown, such that once initially redirected, the ball is slowed by impact with the baffle during its downward descent sufficiently that it can be effectively stopped and retained within the channel at the lower portion thereof when it reaches a stop (or low wall) provided at the front edge of the lower portion of the channel., Such feature provides the optional advantage of permitting use of more than one ball, a benefit being that there will always be a ball available for a subsequent throw already resting at the bottom of the channel from a previous throw.  
         [0034]     A method of exercising practiced in accordance with an embodiment of the invention broadly includes the steps of:  
         [0035]     holding a ball while assuming a reclined position;  
         [0036]     throwing a ball in a forward arc while sitting up such that the ball follows a normal trajectory; and  
         [0037]     directing the ball from the normal trajectory to a redirected trajectory along which the ball travels from an initially redirected position to a retrieval position below the initially redirected position.  
         [0038]     These steps may advantageously be repeated a desired number of times to achieve a desired effect on the muscles of the abdomen and upper body. The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings.  
         [0039]     The invention also includes an exercise device seat attachment having a main body attachable to an exercise device that has a removable seat or stand. A substantially ring-shaped support is provided having a center hole adapted to receive a conventional stability ball. When the main body is attached to an exercise device and a stability ball is placed in the center hole, a user may sit or stand on the stability ball placed in the center hole and use the exercise device. In this way, the user not only obtains the benefit of the exercise performed on the device but also engages his/her abdominal or core muscles at the same time and enjoys much greater benefits as a result.  
         [0040]     In one embodiment, the hole is adapted to receive a stability ball without allowing the stability ball to pass completely therethrough so that it rests on top of the support. The hole may be substantially round or polygonal or any practical shape adequate to receive a stability ball. Preferably, a sleeve is disposed around the support having a relatively high coefficient of friction so that a stability ball placed thereon does not easily slip or slide out inadvertently.  
         [0041]     Preferably, the main body of the attachment is adjustably attachable to the exercise device and may include a pin selectively engageable with one or more holes formed in the exercise device.  
         [0042]     In another embodiment, the inventive exercise device seat attachment has a hole adapted to allow a stability ball to pass completely therethrough. The size of the hole may be varied for increasing or decreasing the overall stability of the attachment, i.e., a snug fitting ball would be more stable (and thus easier to use) than a loose fitting ball.  
         [0043]     In another aspect of the invention, the invention is an exercise device having a main frame and at least one part selectively user-movable with respect to a second part for exercise purposes (e.g., a lat pull-down machine or a seated row machine). A substantially ring-shaped support is attached to the main frame having a center hole adapted to receive a conventional stability ball. When a stability ball is placed in the center hole, a user may sit or stand on the stability ball in the center hole and move the selectively user-movable part with respect to the second part, thereby performing the machine&#39;s exercise while at the same time engaging his/her core muscles.  
         [0044]     As before, the hole may or may not allow the stability ball to pass completely therethrough. The hole may be substantially round, polygonal, or any practical shape. Preferably, a sleeve disposed around the support having a relatively high coefficient of friction to prevent the ball from slipping. The support is preferably adjustably attachable to the main frame and may include a pin attached to one of the support or the main frame selectively engageable with one or more holes formed in the other of the support or the main frame.  
         [0045]     In yet another aspect of the invention, the invention includes an exercise device having a main frame and at least one part selectively user-movable with respect to a second part for exercise purposes. A user support is provided having an attachment portion movably attachable to the main frame, a lower curved surface unstably engaging the floor, and an upper support surface supporting a user while the user moves the selectively user-movable part with respect to the second part. The attachment portion is pivotably attached to the main frame about an axis.  
         [0046]     In one embodiment, the user support includes a substantially rigid top platform incorporating the upper support surface and a flexible substantially hemispherical body attached to an underside of the top platform incorporating the lower curved surface. In this version, the attachment portion is preferably attached to the top platform. In another embodiment, the user support includes a substantially rigid top platform incorporating the upper support surface and a substantially cylindrical lower body attached to an underside of the platform incorporating the lower curved surface. In this version, the attachment portion is preferably attached to the cylindrical lower body. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0047]      FIG. 1  is a perspective view of an apparatus in accordance with an embodiment of the invention;  
         [0048]      FIG. 2  is an exploded view of the embodiment of  FIG. 1 ;  
         [0049]      FIG. 3  is an elevational rear view of the embodiment of  FIG. 1  facing a ball return guide at which a ball will be thrown during use;  
         [0050]      FIG. 4  is a side detail view of the embodiment of  FIG. 1 , which a user will be throwing during use;  
         [0051]      FIGS. 5   a  and  5   b  depicting respective steps performed in the course of a method according to an embodiment of the invention;  
         [0052]      FIG. 6  is an annotated detail view of a seat construction according to an advantageous embodiment;  
         [0053]      FIG. 7  is an annotated detailed rear view of the seat construction of the embodiment of  FIG. 6   
         [0054]     FIG .  8  is an annotated detailed rear view of the seat construction of the embodiment of  FIG. 6 .  
         [0055]      FIGS. 9, 10   a .,  10   b . and  FIGS. 11, 12 , and  13  are two alternative embodiments to serve as illustration of just some of the changes that could be made to the embodiments without departure from the invention.  
         [0056]     FIGS.  14 A-C are top, front, and side elevational views of one embodiment of a user support capable of receiving a stability ball and attachable to an exercise device like that of  FIGS. 1-13  in accordance with the invention.  
         [0057]     FIGS.  15 A-B are top schematic views of alternate embodiments of the user support of  FIG. 14 .  
         [0058]      FIG. 16  is a side elevational view of another embodiment of a user support capable of receiving a stability ball attachable to an exercise device like that of  FIGS. 1-13  in accordance with the invention.  
         [0059]      FIG. 17  is a schematic side elevational view of yet another embodiment of a user support capable of receiving a stability ball attachable to an exercise device like that of  FIGS. 1-13  in accordance with the invention.  
         [0060]     FIGS.  18 A-B are schematic front and side elevational views of still another embodiment of a user support capable of receiving a stability ball attachable to an exercise device like that of  FIGS. 1-13  in accordance with the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0061]     Referring now to  FIGS. 1-8 , an embodiment of the exercise apparatus is shown, generally designated  12 . Apparatus  12  includes a seat  28  comprised of a horizontal portion  24  from at least partially upright position to an at least partially reclining position, respectively, dining performance of the intended exercise. Forward of the seat  28  there is provided a ball return  48  which, in the depicted example, is in the form of a channel presenting a continuously cured back portion  40  extending from the upper portion  42  to a lower portion  44 , such that when a ball  16  is thrown into the upper portion  42  of the arcuate ball return guide  46  the ball is roughly guided by the curvature of the surface of the back portion  40  and is directed to the lower portion  44  where it is retrieved by the user during use. The ball return guide  48  advantageously includes enclosed sides  50  to prevent the ball firm jumping out laterally while following the back curvature Still more advantageously, the sides  50  are wider apart in the region of the upper portion  42  of the channel shaped ball return guide  46 , as shown, to allow for greater margin of error high aiming when the ball is thrown by the user. A pair of bilateral vertical supports  52  and a base  54  conveniently maintain the ball return guide  48  in a fixed position.  
         [0062]     Since the ball traveling along the redirected trajectory while in the ball return guide  46  will be redirected by the ball damper  58 , (Shown in phantom in  FIG. 1 , and- 4 ) to  48  propel into the ball baffle  56 , (Also shown in phantom in  FIG. 1-4 ) slowing it down to the lower portion  44 ,  36  and  36  for the user to retrieve. Still more advantageously, particularly when the ball  16  is thrown into upper portion  42  and ball return guide  46  and selectively installed in the channel of the ball return guide  46  a ball damper  58  and ball baffle  56  for the purpose of slowing the ball down to allow time for the user to retrieve the other ball.  
         [0063]     Optionally, a rebound member  20  is also provided (Shown in  FIG. 2, 3  and in phantom in  FIG. 1 ) Rebound member optionally has a target or bulls eye disposing centrally, as depicted in  FIG. 3  for the improved sight recognition by the user when aiming, which can be moved from a position in which it blocks the front opening to the upper portion  42  of the ball return guide  46  to another position in which the rebound member  20  no longer obstructs the opening, for example, the user would simply pull on pull pin  70  releasing the rebound member  20  exposing upper portion  42 .  
         [0064]     As shown in  FIG. 6, 7 , and  8  in which the details of the seat  28  are highlighted, the backrest  24  is biased by springs  34  connected to the main frame seat  76  in an at least partially upright position. Other features of the seat  28  are annotated on the drawing sheet containing  FIG. 4 . During use, as shown in  FIGS. 5   a  and  5   b , the seat  28  is oriented alternately and brought back to a reclined position after ball retrieval and before a subsequent throw ( FIG. 5   a ) and to an upright (or partially upright) position while throwing the ball ( FIG. 5   b ). A foot restraint  60 , (as shown in  FIG. 4 ) is also advantageously provided suitably located to facilitate the sitting up process for the user.  
         [0065]     The functionality of the apparatus and the various elements have been described above, and therefore further description is believed to be unnecessarily redundant.  
         [0066]     It will be readily apparent to one of ordinary skill in the art that a vast number of different structural configurations can achieve the desired effect within the broad parameters of the inventions described herein. For example, a different manner of support can be implemented, and the apparatus need not be integrated, and instead be provided as separate modules. Also, by way of example, the ball return guide need not be fully enclosed, but instead be provided as an open cage. Furthermore, the rebound member, provided in the depicted embodiment as a rigid plastic or metal part, could also be a tensioned resilient substance, such as a mesh or elastic member.  
         [0067]     Up until now, the discussion has centered around a specific exercise device for improving abdominal or core strength. The invention also includes a seat or user support that may be used with either the above-mentioned exercise device or substantially any exercise device which has a seat or other user support. As shown in FIGS.  14 A-C, user support  100  has a main body  102  which is selectively attachable to a mating attachment portion of an exercise device. Regarding the above device, the seat  24  and  28  would be removed from the lower portion of the frame of the device, and main body  102  would be attachable thereto, preferably resting on the floor. Main body  102  includes a pin housing  106  having a preferably spring-biased pin  108  which is adapted to engage one or more holes formed in the lower portion of the frame of the exercise device, thereby making the placement of user support  100  adjustable with respect to the exercise device. A crossbar  104  secures ring section  110  to main body  102 . Ring section  110  has a central hole  111  that is adapted and dimensioned to receive a portion of stability ball  200  (see FIGS.  14 B-C). A sleeve  112  may be disposed around ring section  110  to provide additional friction so that ball  200  does not readily slip or slide out of engagement with ring section  110 . The main components of support  100  are preferably made of metal or plastic, while sleeve  112  is preferably made from rubber, neoprene, or similar high friction substances.  
         [0068]     In operation, the user removes the conventional seat or stand from an exercise device and attaches user support  100  instead. The user places stability ball  200  into engagement with central hole  111  which allows the ball to sit atop ring section  110  without allowing the ball to pass entirely therethrough. The user then sits or stands on ball  200  and performs the exercise as usual. However, by sitting on the stability ball instead of a regular seat, the user must continually maintain excellent posture and thus engage his or her abdominal muscles to avoid falling off the ball. In this way, any conventional exercise device may now be provided with a significant core/abdominal component by attaching the user support of the present invention.  
         [0069]     The embodiment of  FIG. 14  shows a substantially circular ring section  110 . However, as shown in FIGS.  15 A-B, the ring section may be substantially any shape. For example, ring support  110 A ( FIG. 15A ) is substantially square and has a substantially square center hole  111 A. Ring support  110 B ( FIG. 15B ) is substantially octagonal and has a substantially octagonal center hole  111 B. Any practical shape of ring support is contemplated.  
         [0070]      FIG. 16  depicts a slightly different embodiment of stability ball support than  FIGS. 14-15 . In the previous embodiment, the center hole of the ring support is dimensioned to receive a portion of a stability ball without allowing the ball  200  to pass entirely therethrough. As such, the ball  200  will sit atop ring support  110 . In the embodiment of  FIG. 16 , user support  250  includes a ring support  210  (attached to base  202 ) having a center hole  211  dimensioned to allow a stability ball  200  to pass therethrough and be supported on the floor F. Support  210  may be designed to be attachable to an exercise device either directly as alluded to by arrow A or via base  202  as alluded to by arrow B. Either of these attachments may be accomplished via the spring-biased pin shown in  FIG. 14  or a similar attachment mechanism.  
         [0071]     Yet another embodiment is shown in  FIG. 17  as user support  350 . Here, the unstable surface is integrally incorporated within the attachment itself; no external stability ball is required. In this embodiment, a substantially hemispherical flexible base  300  having a lower curved surface  301  is attached below a substantially rigid platform  303  having a top surface  304 . Platform  303  is pivotably attached to main body  302  via rotatable axle  306  which enables platform  303  to pivot back and forth thereabout as shown with arrow C. As another option, axle  306  may be replaced by a retractable cable which allows greater freedom of movement of platform  303 . Main body  302  is also provided with a spring-biased pin (not shown) or similar adjustable attachment mechanism as described previously. Like a stability ball, base  300  may be made from a springy material and/or an inflatable bladder that elastically deforms when stepped upon and thus does not provide constant and even support. In use, the user sits or stands on surface  304  and attempts to maintain his/her balance while using the exercise device. A torsional spring (not shown) may be employed around axle  306  to increase the stability of the system and reduce the difficulty of balancing on platform  303 .  
         [0072]     Another embodiment which integrally incorporates the unstable curved surface desired into the seat/stand attachment is depicted in FIGS.  18 A-B as user support  450 . Here, the lower portion of the device includes a substantially rigid cylindrical body  400  having a curved circumferential surface  401 . A substantially rigid platform  403  is adapted to support (but not stably) a user standing or sitting thereon. Cylindrical body  400  is attached to main body  402  via axle  406 , which may include a torsional spring (not shown) to increase the stability of the system and reduce the difficulty of balancing on platform  403 . With or without the torsional spring, platform  403  will wobble back and forth about the central axis of body  400  as shown by arrow D in  FIG. 18B . The user sitting or standing thereupon must attempt to maintain his/her balance despite the inherent instability offered by the attachment.  
         [0073]     To serve as illustration of just some of the changes that could be made to the above described embodiment without departure from the invention, two alternative embodiments are shown in  FIGS. 9, 10   a ,  10   b ,  11 , and  FIGS. 12, 13 , respectively.  
         [0074]     These figures are annotated with descriptions relating to the design and functionality of the various component elements, and will be clear to one of ordinary skill in the art without need for further description with reference to reference designators.  
         [0075]     It is further noted that the upper portion of the ball return guide could be further widened or divided into separate openings to facilitate targeting different abdominal muscles by throwing to either side, and in which the ball will be directed to the lower portion regardless of which opening the ball is thrown into. In addition, some form of enclosure or barrier could be implemented to prevent escape of the ball if the opening were to be missed, and which would return the ball to the user without requiring the user to move from the seated position. Other netting or the like could also be provided around the apparatus to prevent loss of the ball if not caught.  
         [0076]     Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention.  
       LIST OF REFERENCE NUMERALS  
       [0077]     With regard to reference numerals used, the following numbering is used throughout the drawings. 
     12 ) present invention      14 ) user      16 ) ball      18 ) ball shoot      20 ) rebound      22 ) back      24 ) backrest      26 ) buttocks      28 ) pivotable platform seat      30 ) feet      32 ) adjustable feet platform      34 ) Gas springs      36 ) ball ramp      40 ) curved channel portion      42 ) upper portion      44 ) lower portion      46 ) ball return guide      50 ) side panels      52 ) vertical supports      54 ) base      56 ) ball baffle      58 ) ball damper      60 ) foot restraints      62 ) ball stop      64 ) ball rack      68 ) foot plate      70 ) pull pin      72 ) rubber bumper      74 ) spring mounts      76 ) seat main frame