Abstract:
An inflatable device can be used for physical therapy, conditioning or training. The device has a support platform and a flexible member. The flexible member is affixed to, and has a bowl-shaped distention projecting from, one side of the platform. This flexible member is inflatable to a pressure for supporting a person. The device is inflated before placing at least some of the weight of a person on the device. When the person wishes to later change the characteristics of the device, the pressure in the inflatable device can be changed to change its stability.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to devices for physical therapy, conditioning or training, and in particular to inflatable devices. 
     2. Description of Related Art 
     Many devices are known for facilitating exercises done for therapy, conditioning or physical training. Other than variable resistance training equipment, these devices have not usually offered much adjustability to allow for exercises at different degrees of difficulty. Also, many of these devices have been dedicated to very specific exercises and therefore do not justify a significant investment of space and financial resources for such a narrow purpose. 
     Some exercise devices require a person to maintain balance and equilibrium. A large inflatable ball (for example, 65 cm), known as a Swiss ball, has been used for this purpose. While the ball is useful for certain stability training exercises, standing upon the ball or staying atop the ball requires a high degree of skill and is inappropriate for most. 
     In U.S. Pat. No. 4,801,140 a person suffering from a physical disability can stand on the flat side of a non-inflatable molded foam hemisphere to practice balancing. The practical disadvantage of this design is that a high degree of skill is required before someone can actually stand on such an unstable platform. Without assistance from a therapist or additional balancing accessories, this platform is accessible only to trained athletes. 
     In U.S. Pat. No. 5,810,703 the underside of a small board is fitted with a smaller spherical projection. The relatively small diameter of the spherical projection tends to make the board relatively unstable. The height of the spherical projection can be set to one of three discrete settings. Overall, the adjustment has little range and resolution. Also, the projection, if inverted to face upwardly, is too small to allow a person to perform an exercise while placing weight on the projection. 
     An inflated cushion in the shape of a disk (sold under the name DuraDisk through C.H.E.K. Institute) has been described as useful for certain exercises. This cushion is described as needing no inflation, but the product is shipped with an inflation valve that the user has access to. A separate wooden platform, 20 inches in diameter, is sold for the purpose of placing the platform over the cushion to create a balance board. This cushion is relatively flat and therefore offers little challenge to a user. It is not useful for the inflatable disk to be placed on the board as this would offer no advantage over putting the inflatable disk on the floor. Also, the use of a separate platform requires careful placement and centering of the platform and also introduces the need for regularly finding and associating the separate parts. 
     In U.S. Pat. No. 5,643,154 a relatively squat, rounded ballast is mounted under a relatively wide platform. If the user is willing to stock an inventory, the rounded ballast can be a changed, but the individual ballasts are not adjustable. This device is designed for use on land or in water. For use in water, an edge bumper is inflated an adjustable amount to reach the desired buoyancy. While this edge bumper is adjustable, this adjustment is only effective in water. The stability of the platform on land will not be substantially affected by adjusting an edge bumper, which inherently provides a stable base. See also U.S. Pat. No. 3,024,021 for a non-adjustable device employing a platform connected through a resilient member to a rounded base. 
     U.S. Pat. No. 5,643,165 shows a frustroconical balancing device with a flattened apex. This device is stable in only one central position, and becomes highly unstable once tilted slightly. Furthermore, the stability of this device is not adjustable. See also U.S. Pat. No. 5,549,536 for a continually tilted platform. 
     Accordingly, there is a need for an improved device that can allow adjustment, preferably with an inflatable device, to accommodate persons with different levels of skills and capabilities. 
     SUMMARY OF THE INVENTION 
     In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a device for physical therapy, conditioning or training. The device has a support platform and a flexible member. The flexible member is affixed to, and has a bowl-shaped distention projecting from, one side of the platform. This flexible member is inflatable to a pressure for supporting a person. 
     In accordance with another aspect of the invention there is provided, a method for physical therapy, conditioning or training. The method employs an inflatable device having a flexible member distending from a platform. The method includes the step of inflating the inflatable device. Another step is placing at least some of the weight of a person on said inflatable device. The method also includes the steps of removing the weight of the person and changing the pressure in the inflatable device to change its stability. Another step is again placing at least some of the weight of a person on said inflatable device. 
     By employing devices and methods of the foregoing type, a variety of exercises can be performed by persons of varying levels of skills and capabilities. In a preferred embodiment a flexible, sheet-like member is affixed along the edge of a rigid circular platform, though other non-circular outlines are contemplated. This preferred, sheet-like member can be inflated by a valve installed, for example, in the center of the platform. When inflated, the flexible, sheet-like member forms a domed or hemispherical surface, at least before being loaded. 
     In some embodiments a circular panel can be attached to the underside of the platform to sandwich between them an edge of the flexible, sheet-like member. The edge of the platform may have an upwardly extending lip formed by either rolling the edge of the platform, or by attaching a bead to the platform&#39;s edge. In some embodiments the edge of the flexible, sheet-like member can be sandwiched between the bead and the platform. 
     In some cases the user may place the flexible, sheet-like member on the ground and then stand on the platform to enhance the user&#39;s balance. The stability of the platform can be altered by adjusting the pressure behind the flexible, sheet-like member. In other cases the user may place the platform on the ground and then stand on the inflated flexible, sheet-like member. This orientation may facilitate balance exercises, or toe extensions that exercise the calves. Numerous other exercises can be performed when the person uses the flexible, sheet-like member for sitting or supporting a hand, foot, extremity, etc., while performing situps, squats, lunges, etc. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is an axonometric view of a device in accordance with principles of the present invention; 
     FIG. 2 is a side elevational view of the device of FIG. 1, showing various levels of distension; 
     FIG. 3 is a detailed, fragmentary, cross-sectional view of the device of FIG. 1, but modified to include an additional bead; 
     FIG. 4 is a detailed, fragmentary, cross-sectional view of a device that is an alternate to that of FIG. 2; 
     FIG. 5 is a detailed, fragmentary, cross-sectional view of a device that is an alternate to that of FIG. 2; 
     FIG. 6 is a plan view of a device that is an alternate to that of FIG. 1; and 
     FIGS. 7A-7D show the device of FIG. 1 being used in a variety of exercises. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, the illustrated device has a support platform  10  with a circular outline, although other outlines are contemplated (elliptical, polygonal, etc.). Platform  10  can be made of wood, plastic, metal, or other materials. A flexible sheet-like member in the form of an elastomeric sheet  12  is shown secured to the edge of platform  10 . The edge of sheet-like member  12  is attached with an airtight seal to platform  10  by glueing, by clamps, or by other sealing means. Sheet-like member  12  can be made of any one of a variety of materials, including natural and synthetic rubbers, plastics, etc. Also, in some embodiments sheet-like member  12  may be a laminate having an outer surface that is more durable and skid resistant. 
     Sheet-like member  12  may be formed by blow molding or otherwise to have a natural hemispherical shape. This hemispherical shape preferably has a diameter of 18 to 36 inches (46 to 91 cm), although other dimensions are contemplated. It will be appreciated, however, that under normal use, and when loaded, the sheet-like member  12  will have a profile that is more complex than a hemisphere. In other embodiments, sheet-like member  12  may start as a flat circular sheet that distends when inflated into a dome (taking essentially a hemispherical shape when unloaded). 
     A valve means  14  is mounted in a center hole in platform  10 . The valve means  14  may be a rubber bushing covered on its inside with a flexible flap that acts as a check valve. Valves of this type are used to inflate basketballs, footballs, etc. If the device need only be inflated to a relatively low pressure, a tube with a stopper can permit a user to blow into the tube to inflate the device, as is done with inflatable beach balls, and the like. Various other types of valves can be used in different embodiments, depending upon the desired pressure, pumping method, etc. Also, valve  14  can be located on alternate positions on platform  10 , or on various positions on sheet-like member  12 . 
     Referring to FIGS. 1 and 3, a circular deck  16  is shown as an element attached to the underside of platform  10  by means of screws  18 , although other types of fasteners may be used instead. The edge of sheet-like member  12  is shown sandwiched between platform  10  and underlying deck  16 . The seal at the edge of sheet-like member  12  can be enhanced by using an appropriate glue, caulk, gasket compound, or other sealing material. The hole holding valve means  14  is aligned with hole  20  in underlying deck  16 , although such alignment is unnecessary, and in some embodiments a number of spaced holes may be used instead. Platform  10  and deck  16  may be made of different materials, so that the outer surface may be flexible and skid proof, while the inside deck may be rigid and able to bear heavy loads. In still other embodiments, underlying deck  16  may be replaced with a hoop or other annular structure to simply concentrate on its function of acting as an affixing means for sealing sheet-like member  12  to platform  10 . 
     The edge of platform  10  is fitted with an annular bead  22 . Bead  22  may be secured by glueing or by various fasteners. Also, bead  22  may have a variety of shapes. Bead  22  can be formed of a length of extruded rubber or plastic that is closed into a loop. Alternatively, bead  22  may be initially molded as an annulus. Preferably, the top of bead  22  rises above the surface of platform  10  to provide a small barrier that tends to keep a user&#39;s feet on the platform. Also in preferred embodiments, bead  22  may be relatively soft material that prevents injury caused by the user accidentally kicking or otherwise colliding with the edge of platform  10 . 
     Referring to FIG. 4, alternate platform  10 ′ is similar to the previously described platform, but with a peripheral recess  24 . An annular bead  26  is shown fitted in recess  24 , while sandwiched between them is previously mentioned sheet-like member  12 . As before, bead  26  may be a molded annulus or may be formed from a length of extruded material that is closed into a loop. Alternatively, the edge of sheet-like member  12  may be sealed into recess  24  before molding bead  26  in situ. Bead  26  has an outside surface that is coplanar with the outside surface of platform  10 ′ to facilitate situations where the device is placed with platform  10 ′ down, for certain exercises to be described presently. 
     Referring to FIG. 5, previously mentioned deck  16  is shown attached by means of screws  18  to alternate platform  10 ″. Also as before, sheet-like member  12  is sandwiched between elements  10 ″ and  16 . Platform  10 ″ has an integral edge  28  that is rolled. Platform  10 ″ maybe shaped by molding, stamping, bending, etc. 
     Referring to FIG. 6, an alternate platform  10 ′″ is generally rectangular with rounded corners. Platform  10 ′″ to be dimensioned to simulate the general size and feel of a skate board or snowboard. Here, two inflatable domes  30  are sealed to the underside of platform  10 ′″ using structure and techniques similar to that previously described. The domes  30  are arranged so that the platform  10 ′″ can roll (rotation about a longitudinal axis) fairly easily, but cannot pitch unless the user places significant weight at the front or back of the platform  10 ′″. 
     To facilitate an understanding of the principles associated with the foregoing apparatus, the use of the device of FIG. 1 will be briefly described. The user will initially inflate the device by inserting a pump needle through valve means  14 . The sheet-like member  12  will be inflated and will distend accordingly. With a modest level of inflation, sheet-like member  12  will take the hemispherical shape  12 A shown in FIG. 2 when unloaded (that is, when suspended so that the sheet-like member  12  does not touch the ground). 
     The foregoing device may be used with the platform  10  resting on the ground as shown in FIG.  7 A. Here, a person P stands on sheet-like member  12 , working to maintain balance. For an especially challenging session, a person can stand on one foot. The difficulty can be further increased if the person to P rolls or tilts the head, with or without the eyes closed. Another, surprisingly challenging session can consist of simply kneeling on the sheet-like member  12 . This effort can be reduced for a novice by getting down on all fours and then working to maintain balance. 
     The person P may mount sheet-like member  12  in order to receive various benefits. The user may perform an exercise in order to improve the user&#39;s sense of balance. In some cases, the user may suffer from a disability that affects coordination and balance. Therefore, the device can be used to improve motor skills and balance as a form of therapy. In other cases, an athlete may wish to improve balance for any one of a number of sports requiring a refined sense of balance. Alternatively, the user may stand on member  12  simply to exercise his or her muscles. Of course, some users will stand on member  12  simply for enjoyment. 
     The amount of exercise sustained by mounting the device can be substantial. The person maintaining balance will normally be required to make many rapid and urgent posture adjustments by exerting a wide range of muscles. Moreover, this effort takes place with a sense of stimulation and excitement that makes the effort challenging and interesting. Thus, the user can quickly reach a high level of exertion without the usual sense of tedium or labor. 
     As the user&#39;s balance, coordination, and endurance improve, the user may wish to increase the level of difficulty. Accordingly, the pressure within the device can be decreased by venting valve means  14 . This reduced pressure leads to less sure footing and increased effort to maintain balance. Alternatively, the pressure can be increased to accommodate an especially difficult routine, or to accommodate a user that is tired or less experienced. This increased pressure corresponds to more stability, since the sheet-like member  12  is less able to shift underneath the user. An advantage with the foregoing pressure adjustment is that the user can continuously and finely adjust the pressure and the level of difficulty to suit his or her personal needs. 
     Because the device can be adjusted to become relatively stable, the user can readily perform ordinary exercises. For example, the user can squat, or stretch and stand on his or her toes as an exercise. Such exercises provide the dual benefit of conditioning muscles, while simultaneously training a person to maintain balance. Other exercises are contemplated, such as leg kicks, knee lifts, etc. 
     A person P can also sit on sheet-like member  12  as shown in FIG. 7B to perform situps. Here, the user can decrease the level of difficulty by shifting forward to reduce the amount of upper body weight that is cantilevered out past the device. An additional advantage is that sheet-like member  12  can conform to the user&#39;s body and support the lower back as the user leans back. 
     Decreasing the pressure within sheet-like member  12  can increase the amount of lower back support under such circumstances. 
     Various other exercises can be performed on the inverted device. As shown in FIG. 7C, person P can perform lunges. In fact, many of the exercises that are performed in step aerobics classes can be performed with the presently disclosed device. One advantage with this mode of use is that the exercise is very low impact, since sheet-like member  12  acts like a cushion. Again, the pressure behind sheet-like member  12  can be adjusted to change the level of difficulty. Also, the cushioning effect of sheet-like member  12  can make the exercises low impact, which is very important in step aerobics in order to avoid the joint injury that commonly occur with long-term use. 
     The foregoing device need not be used with the platform down, but may be inverted at shown in FIG.  7 D. Because the device is inherently less stable when inverted as in FIG. 7D, the user will receive a more vigorous experience, which may be appropriate for athletic training. 
     When placed on the ground (level G 1  of FIG. 2) in order to support a person as shown in FIG. 7D, sheet-like member  12  will become more squat and take the outline  12 A shown in phantom in FIG.  2 . This is a relatively stable condition and the user can maintain balance while standing on platform  10  without too much difficulty. 
     Pressure can then be increased by reattaching a pump to valve means  14 . Sheet-like member  12  may then be pressurized to distend further and take the outline  12 B shown in phantom in FIG. 2, when placed on the ground at level G 2 . Outline  12 B is closer to hemispherical and will make the platform  10  less stable. If the device is built sufficiently strong to sustain a very high pressure, sheet-like member  12  can distend to the almost precisely hemispherical shape shown in full line in FIG.  2 . This represents the highest level of difficulty, requiring a high level of skill and endurance. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.