Patent Publication Number: US-6213923-B1

Title: Back exercise device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to exercise devices, and more particularly, to exercise devices for strengthening muscles of the lower back and abdominal muscles. Specifically, this invention relates to a device for imparting extension to the spine of a user. 
     2. Description of the Related Art 
     Lower back pain is a common complaint. Often lower back pain is associated with sedentary lifestyles. Posture responsible for lower back pain may be related to occupations or lifestyles which include a large amount of sitting and/or leaning forward. Poor lifting and bending posture may also result in lower back pain. Recently, it has been recognized that a majority of back pain is mechanical in origin, and that physical activity is the cornerstone of low-back rehabilitation. 
     One recognized treatment for chronic lower back pain is physical exercise including extension of the spine. As used herein, “extension of the spine” refers to movement which bends the spine backwards through contraction of the lumbar extensor muscles. In the past, exercises for extending and strengthening the lower back have included floor exercises and exercises using inversion therapy devices. A floor exercise program for developing back strength may be difficult to implement and maintain for some patients who have weak backs or are poorly conditioned. Furthermore, the amount of spinal extension provided by such floor exercises is typically limited. 
     Inversion therapy devices are typically relatively expensive and bulky, and relatively difficult to operate by one person. Common inversion therapy devices include those having a tiltable table for supporting a user in a number of different positions. Such devices typically include foot clamps attached at one end of the table for suspending the patient when the table is placed in an inverted position. A user typically mounts such a device with the table in near-upright position and straps their feet to foot clamps at the base of the table. The user may then be positioned in various positions of partial and full inversion by tilting and rotating the table backwards. Besides being bulky and relatively expensive, such inversion devices may cause or aggravate health problems for hypertensive individuals. In addition, while inversion devices may provide some unloading of the spinal column of the lower back by virtue of gravity inversion, no spinal extension is typically imparted to the user due to the flat surface of the table. 
     SUMMARY OF THE INVENTION 
     Disclosed is a device and method for greatly improving the strength and flexibility of the lower back, abdominals and obliques of, for example, both individuals who are suffering from lower-back pain, and individuals who do not suffer from lower-back pain but who wish to gain strength and flexibility in the their lumbar extensor muscles. The disclosed method and device may be used to provide a user with the ability to strengthen and stabilize lumbar extensor muscles through extension movements as well as the abdominals and obliques through flexion movements. The lower back and hamstrings may also be kept flexible to minimize back strain or sprain. Due to its relatively simple design and wide range of decline angle and resistance control(s), the disclosed device facilitates regular workouts for users having lower back pain. Such regular exercise may help alleviate lower back pain relatively quickly, and may strengthen muscles that support the back to improve flexibility, and reduce the chance of future acute attack. 
     Advantageously, the disclosed device is relatively compact and simple to use to provide extension to a user&#39;s back in addition to unloading of the spinal column. Using the disclosed device, a user may strengthen lower back and abdominal muscles, plus increase and maintain flexibility in the trunk, so as to reduce the incidence of future low-back pain. Further advantageously, the disclosed device may also serve as a static workout bench for whole body strength-training program. Thus, one disclosed embodiment is a relatively inexpensive and compact exercise device which provides the combined functions of a back extension machine, abdominal conditioning machine and weight bench. 
     Surprisingly, use of the disclosed device and method allows users suffering lower-back pain to reduce future incidence of such pain by strengthening and increasing flexibility in the lower back while comfortably positioned off the floor, rather than lying and performing traditional back exercises on a floor. By providing extension to the spinal column, the disclosed method and device address low-back pain in a manner superior to traditional or conventional inversion devices which utilize a flat table. In one embodiment, a foam-padded backrest and seat help support a user&#39;s body throughout the range of motion, and optional lumbar support may be provided. 
     As a further advantage, one embodiment of the disclosed method and device allows a user to customize the degree of extension according to physical ability and/or doctor&#39;s or chiropractor&#39;s advice. 
     Advantageously, in various other embodiments, an adjustable footbar, hand hold positions, and relatively simple decline and resistance controls allow the disclosed device to be operated by users from poorly conditioned beginners to well-conditioned athletes. Furthermore, a wide assortment of settings, wide backrest and features noted above also make the disclosed device ideal for use by an entire family. 
     In one exemplary embodiment, the disclosed device is an adjustable chair which may be declined at varying angles by a user. Advantageously, the angle of decline as well as the amount of resistance inherent in the movement of the chair may be easily controlled by the user. Furthermore, the angle of decline may exceed 180° as measured between the plane of the backrest and the plane of the seat of the chair so as to result in extension of the spine, thus providing superior motion for back rehabilitation as compared to conventional methods and devices employing flat-surfaces. 
     In one respect, disclosed is an exercise device including a back rest having a first surface and first and second ends; a seat having a first surface and first and second ends, the first end of the seat being disposed adjacent the second end of the back rest, wherein a plane of the back rest and a plane of the seat define an angle of decline between the first surface of the back rest and the first surface of the seat; and a support frame supporting the back rest and the seat, wherein the back rest and the seat are pivotally movable relative to each other so that the angle of decline may be adjustable. The back rest and the seat together may be adapted to receive a user in an exercise position wherein the first surface of the back rest supports an upper back of the user, and wherein the first surface of the seat supports a posterior of the user. The angle of decline may be adjustable from an angle of less than about 180° to an angle of greater than about 180°. The angle of decline may also be adjustable between a minimum angle and a maximum angle, the minimum angle being from about 65° to about 215°, and the maximum angle being from about 180° to about 235. 
     The exercise device may further include a decline control mechanism, the decline control mechanism being operable to limit adjustment of the angle of decline. In this regard, the decline control mechanism may be operable to limit adjustment of the angle of decline to a maximum decline angle of from about 180° to about 235°. Additionally or alternatively, the decline control mechanism may be operable to resist adjustment of the angle of decline, and in one embodiment, the decline control mechanism may be operable to selectively prevent or resist adjustment of the angle of decline. In another embodiment, the decline control mechanism may be selectively operable to limit adjustment of the angle of decline to at least two different operable decline angle ranges. 
     In another respect, this invention is an exercise device, including a back rest having first and second ends; a seat having first and second ends, the first end of the seat being pivotably attached to the second end of the back rest at a device pivot point, wherein a plane of the back rest and a plane of the seat form an angle of decline therebetween; and a support frame pivotally supporting the back rest at a first point positioned between the first and second ends of the back rest, and pivotally supporting the seat at a second point positioned between the first and second ends of the seat. The back rest and the seat together may form an extension platform capable of receiving a user in an exercise position wherein the first surface of the back rest supports an upper back of the user, and wherein the first surface of the seat supports a posterior of the user; and the angle of decline may be adjustable up to a maximum value of from about 180° to about 235°. In one embodiment, the maximum angle of decline may be sufficient to cause extension of the back of the user when the user may be received by the first surfaces of the back rest and the seat. The angle of decline may be adjustable between a minimum angle and the maximum angle, the minimum decline angle being from about 65° to about 180°. 
     The exercise device may further include a decline control mechanism operable to limit a range of adjustment of the angle of decline, operable to resist adjustment of the angle of decline, or both. In one exemplary embodiment, the decline control mechanism may have a trailing arm having first and second ends and a decline control slot defined therein between the first and second ends of the trailing arm, the decline control slot being closed at each end; the first end of the trailing arm being pivotally attached to the extension platform at a point adjacent the device pivot point; and a decline control pin connected to the support frame, the decline control pin being received in the decline control slot so that adjustment of the angle of decline causes the decline control slot to slidably travel about the decline control pin, the adjustment of the angle of decline being limited to an operable decline angle range by contact of each of the closed ends of the control slot with the decline control pin. The operable decline range may have a minimum angle of decline of less than about 180° and a maximum angle of decline of greater than about 180°. 
     The decline control mechanism further may have a friction control mechanism connected to the support frame, the friction control mechanism being adapted to contact and frictionally resist slidable travel of the decline control slot about the decline control pin. The friction control mechanism may have a brake control wheel having a brake surface, the brake control wheel being threadably received on the decline control pin so as to have an axis of rotation centered around the decline control pin; and wherein threadable rotation of the brake control wheel about the decline control pin causes the brake surfaces to contact the trailing arm so as to adjustably and frictionally resist sliding movement of the decline slot of the trailing arm about the decline pin, wherein an amount of the frictional resistance may be controllable by threadable rotation of the brake control wheel. 
     The decline control pin may be adjustable relative to the decline control slot defined in the trailing arm so that the maximum angle of decline may be varied to provide variable operable decline angle ranges. The decline control mechanism may be connected to the support frame and may have a decline control slot and a decline control knob threadably received on the decline control pin, the decline control slot being configured to receive the decline control pin and the decline control knob adapted to secure the decline control pin to the decline control slot in two or more different decline positions, wherein in each of the two or more different decline positions a position of the decline control pin relative to the decline control slot may be different so that the maximum angle of decline may be different, providing two or more operable decline angle ranges. The decline control pin may be adjustable relative to the decline control slot defined in the trailing is arm so that the maximum angle of decline may be varied to provide variable operable decline angle ranges. 
     In another embodiment, the first surface of the back rest further may have a lumbar support structure, the lumbar support structure adapted to provide supplemental support to the back of the user. The exercise device may further include at least one hand grip connected to the back rest and adapted to provide grip support for at least one hand of the user when in the exercise position, and/or a foot rest connected to the seat and adapted to provide support for the feet of the user when in the exercise position. The exercise device also may further include a support bar pivotally attached to the support frame and operable to selectively and statically support the back rest at an angle of decline that places the user in a supine position. 
     In another respect, disclosed is an exercise device, including a back rest having first and second ends; a seat having first and second ends, the first end of the seat being pivotably attached to the second end of the back rest at a device pivot point, wherein a plane of the back rest and a plane of the seat form an angle of decline therebetween; and a support frame pivotally supporting the back rest at a first point positioned between the first and second ends of the back rest, and pivotally supporting the seat at a second point positioned between the first and second ends of the seat; a decline control mechanism, including a trailing arm having first and second ends and a decline control slot defined therein between the first and second ends of the trailing arm, the decline control slot being closed at each end; the first end of the trailing arm being pivotally attached to the extension platform at a point adjacent the device pivot point, a decline control pin connected to the support frame, the decline control pin being received in the decline control slot so that adjustment of the angle of decline causes the decline control slot to slidably travel about the decline control pin, the adjustment of the angle of decline being limited to an operable decline angle range by contact of each of the closed ends of the control slot with the decline control pin, a friction control mechanism including a brake control wheel having a brake surface, the brake control wheel being threadably received on the decline control pin so as to have an axis of rotation centered around the decline control pin; and wherein threadable rotation of the brake control wheel about the decline control pin causes the brake surfaces to contact the trailing arm so as to adjustably and frictionally resist sliding movement of the decline slot of the trailing arm about the decline pin, wherein an amount of the frictional resistance may be controllable by threadable rotation of the brake control wheel, and a decline control knob threadably received on the decline control pin, the decline control slot being configured to receive the decline control pin and the decline control knob adapted to secure the decline control pin to the decline control slot in two or more different decline positions, wherein in each of the two or more different decline positions a position of the decline control pin relative to the decline control slot may be different so that the limits of the angle of decline may be different, providing two or more operable decline angle ranges. 
     The back rest and the seat together may form an extension platform adapted to receive a user in an exercise position wherein the first surface of the back rest supports an upper back of the user, and wherein the first surface of the seat supports a posterior of the user; and the angle of decline may be adjustable up to a maximum value of from about 180° to about 235°. 
     The exercise device may further include first and second hand grips connected to the back rest and adapted to provide support for the hands of the user when in the exercise position; a foot rest connected to the seat and adapted to provide support for the feet of the user when in the exercise position; and the first surface of the back rest further may have a lumbar support structure, the lumbar support structure adapted to provide supplemental support to the back of the user. In addition, the exercise device may further include a support bar pivotally attached to the support frame and operable to selectively and statically support the back rest at an angle of decline that places the user in a supine position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified front perspective view of an exercise device according to one embodiment of the disclosed method and apparatus. 
     FIG. 2 is a simplified rear perspective view of an exercise device according to one embodiment of the disclosed method and apparatus. 
     FIG. 3 is a simplified rear perspective view of an exercise device according to one embodiment of the disclosed method and apparatus. 
     FIG. 4 is a simplified exploded view of the components of a decline control mechanism according to one embodiment of the disclosed method and apparatus. 
     FIG. 5 is an enlarged partial view of a decline control mechanism according to one embodiment of the disclosed method and apparatus. 
     FIG. 6 is a simplified rear perspective view of an exercise device according to one embodiment of disclosed method and apparatus. 
     FIG. 7 is a simplified exploded view of a support frame according to one embodiment of the disclosed method and apparatus. 
     FIG. 8 is a simplified rear exploded view of an exercise device according to one embodiment of the disclosed method and apparatus. 
     FIG. 9 is a simplified side view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing a user positioned on the exercise device at an angle of extension of about 65°. 
     FIG. 10 is a simplified side view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing a user positioned on the exercise device at an angle of extension of about 180°. 
     FIG. 11 is a simplified side view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing a user positioned on the exercise device at an angle of extension of about 235°. 
     FIG. 12 is a simplified side view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing a user positioned on the exercise device at an angle of extension of between about 180° and about 235°. 
     FIG. 13 is a simplified perspective view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing a user positioned on the exercise device and performing abdominal crunches. 
     FIG. 14 is a simplified side view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing the exercise device positioned at an angle of extension of about 65°. 
     FIG. 15 is a simplified side view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing the exercise device positioned at an angle of extension of about 180°. 
     FIG. 16 is a simplified side view of an exercise device according to one embodiment of the disclosed method and apparatus, and showing the exercise device positioned at an angle of extension of about 235°. 
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     FIG. 1 illustrates an exemplary embodiment of the disclosed exercise device which may be used to provide improved strength, flexibility and stability of lumbar and abdominal musculature. As shown in FIG. 1 the device comprises a declinable chair  8  which includes backrest  10  and seat  12  which are pivotally connected at chair pivot point  14 . Seat portion  12  and backrest portion  10  may be suitably dimensioned for supporting a human user. Although particular embodiments of a declinable chair are described and illustrated herein, it will be understood with benefit of this disclosure by those of skill in the art that dimensions and shape of the components of declinable chair  8  may be varied in many ways, for example, to suit different body sizes and weights including, but not limited to, for children, professional athletes, adults, etc. In one embodiment, the disclosed exercise device has a declinable chair and attached support frame designed for supporting a user of up to about 300 pounds in weight. 
     as As shown, declinable chair  8  may be supported by support frame  16 , in this case a tubular support frame having the shape of an inverted “V”. Chair  8  is shown pivotally supported by frame  16  at two points, seat pivot point  18  and backrest pivot point  20  (which may be more clearly seen in FIGS. 2,  6 ,  7  and  8 ). As illustrated in the figures, chair  8  is declinable by virtue of the combination of respective pivotable points  14 ,  18  and  20 . The degree of decline of chair  8  may be measured in terms of the “angle of decline” formed between the plane of seat  12  and the plane of backrest  10 . For example, FIG. 14 illustrates chair  8  in a position having an angle of decline  11  of about 65°. FIG. 15 shows declinable chair  8  in a position having an angle of decline  11  of about 180°. FIG. 16 illustrates declinable chair  8  in a position having an angle of decline  11  of about 235°. In this regard, the dashed lines present in FIGS. 14-16 are intended to represent the respective planes of seat  12  and backrest  10 . 
     In the illustrated embodiment, pivot point  14  may be a hinge which serves to pivotally join seat  12  to backrest  10  as shown. Although a hinge is employed in this embodiment, any other suitable device for pivotally joining a seat  12  to a backrest  10  may be employed including, but not limited to, rod/axle configurations, single-piece pliant connectors, etc. Similarly, pivot points  18  and  20  are shown as pivotal rods extending between side frame members of support frame  18  and joined to seat  12  and backrest  10  by fasteners. However, any other suitable manner of pivotally attaching declinable chair  8  to support frame  16  may be employed including, but not limited to, independent rodless pivot point attachments to a support frame (such as via bolts or studs attached to frame  16 ), etc. 
     A support frame may be of any material and/or design suitable to support a person or user when in the seated position including, but not limited to, frames constructed of members having a cross-sectional construction of a hollow tube, solid rod, mixtures thereof, etc. In this regard, a frame material may desirably be selected to be relatively rigid so as to support the weight of an individual, as well as to absorb repeated extension movements without fatiguing. Suitable materials for a support frame include, but are not limited to, metal, plastic, wood, fiberglass, mixtures thereof, etc. Furthermore, although an inverted “V” shaped support frame  16  is illustrated, it will be understood that any other suitable support frame configuration and/or shape for pivotally supporting a declinable chair  8  may be employed. For example, a support frame  16  may alternatively be a frame having an “H” shape, “A” shape, inverted “U” shape, etc. 
     Backrest  10  and seat portion  12  of a declinable chair  8  may be constructed of any suitable material and design suitable to support a person or user when performing extension exercises as described herein. Backrest  10  and/or seat portion  12  may also be padded if so desired, although padding is not necessary. In various exemplary embodiments, back rest  10  and seat portion  12  may be plastic-molded, cushioned with cloth or upholstered-covered foam padding mounted on a rigid support surface (such as flat wood, plastic, fiberglass, metal, etc.), or of any other suitable design. Furthermore, although one embodiment of backrest  10  and seat portion  12  having particular respective flat surface profile shapes of each is illustrated herein, it will be understood with benefit of this disclosure that any other backrest and/or seat flat surface profile shape may be employed that is suitable for supporting a person or user when performing extension exercises as described herein including, but not limited to, rectangular, triangular, oblong, oval, etc. 
     FIGS. 7 and 8 are exploded views of support frame  16  and reclinable chair  8  respectively. In particular, FIG. 7 illustrates seat pivot point  18  which includes pivot bar  19  extending between and attached to tubular side members of tubular support frame  16 . Seat pivot bar  19  includes slide points  21  on which the underside of seat  12  may pivot and slide during exercise. FIGS. 7 and 8 also illustrate pivot bar  23  which extends between, and is rotatably attached to, tubular side members of support frame  16  at pivot point  20 . Pivot bar  23  is attached to the underside of backrest  10  via attachment points  25 , typically with fasteners  27 . Thus, during exercise backrest  10  pivots about the axis of pivot bar  23  while seat  12  rotatably slides across slide points  21  of pivot bar  19 . Although one exemplary embodiment of pivot points  18  and  20  has been illustrated, it will be understood with benefit of disclosure by those of skill in the art that any suitable mechanism may be employed at each of these points for allowing seat  12  and backrest  10  to pivot in coordinated fashion to allow angle of decline to vary between the operable ranges described herein. For example, pivot bar  19  may or may not be rotatable in relation to frame  16 , and likewise pivot bar  23  may be a fixed axle about which one or more attachment points  25  are rotatably or pivotally fixed to allow backrest  10  to pivot about the axis of pivot bar  23 . 
     A declinable chair  8  comprising only a seat  12 , backrest  10 , and support frame  16  provides an apparatus for exercising and extending the lower back. However, other optional features may be desirable. In this regard, an optional decline control mechanism  22  may also be provided to control the range of adjustment allowed for angle of decline  11 , and/or to control resistance to adjustment or changes in angle of decline  11 . A decline control mechanism  22  may control either resistance, range of decline angle, or both, and may comprise any mechanism suitable for doing so. For example, a decline mechanism may include springs, mechanical shock absorbers, rubber bands (e.g., bungee-like bands), etc. 
     FIG. 4 illustrates individual components of one exemplary embodiment of decline control mechanism  22 . As shown in FIG. 4, decline control mechanism  22  includes a trailing arm  24  pivotably connected to declinable chair  8  at point  26  adjacent pivot point  14 . Trailing arm  24  includes a decline control slot  28  defined in the body of trailing arm  24 . Decline control slot  28  has closed ends and is dimensioned to receive and to be secured by decline control pin  30  which attaches to support frame  16  at control pin mounting bracket  32 . Decline control pin  30  is dimensioned to be slidably received in decline control slot  28 , such that its relative position in slot  28  varies with adjustment of the angle of decline  11  of chair  8 . Thus, the range of angle of decline  11  is limited by the length of decline control slot  28  by virtue of contact of decline control pin  30  with the closed ends of decline control slot  28 . The term “operable decline angle range” refers to the range of different decline angles possible with a reclinable chair  8 , with the lower limit of the operable decline angle range being the minimum decline angle and with the upper limit of the operable decline angle range being the maximum decline angle possible. In this exemplary embodiment, absolute minimum and maximum angles of decline achievable by chair  8  are relative to the placement of decline control pin  30 . 
     It will be understood with benefit of this disclosure that by varying the length of decline control slot  28  and/or the position of decline control pin  30 , the operable decline angle range as well as the maximum and minimum decline angles may be selectively varied as desired. Furthermore, by providing for adjustment of the relative position of decline control pin  30 , the operable decline range may be selectively or adjustably varied by the user. In one embodiment, a maximum angle of decline may be about 180°. In another embodiment, a maximum angle of decline may be greater than about 180°, so as to provide for extension of the back of a user. In another embodiment, maximum angle of decline may be a value from about 180° to less than or equal to about 245°, alternatively from about 180° to less than or equal to about 235°. A minimum angle of decline may similarly vary but in one embodiment may be less than about 180°. In another embodiment, the minimum angle of decline may be from less than or equal to about 180° to greater than or equal to about 60°, alternatively from about 180° to greater than or equal to about 65°. In a further embodiment, the angle of decline may be adjustable throughout an operable decline angle range having a minimum angle and a maximum angle, with the minimum angle being from about 60° to about 180° (alternatively from about 65° to about 180°), and the maximum angle being from about 180° to about 245° (alternatively from about 180° to about 235°). In yet a further embodiment, an operable decline range may have a minimum angle of from about 65° to about 180°, with a maximum angle selectively adjustable between angles of about 180°, about 215° and about 235°. Notwithstanding these exemplary decline angle embodiments, it will be understood by those of skill in the art with benefit of this disclosure that an operable decline angle range, as well as the absolute values of maximum and/or minimum decline angles, may be varied to be outside the above-given ranges (including greater and/or lesser angles) as so desired to meet different applications and users&#39; needs. Furthermore, it will be understood that by varying support frame  16  so as to increase the distance of chair  8  from a floor surface  200 , greater maximum angles of decline may be achievable. 
     As shown in FIG. 4, control pin mounting bracket  32  has a control pin adjustment slot  36  defined therein. Adjustment slot  36  is configured to receive decline control pin  30  which is held in place by decline control pin knob  34 . An optional indicator  38  is also provided for referencing the position of knob  34 . Decline control pin knob  34  is threadably received by decline control pin  30  and serves to selectively or adjustably secure decline control pin  30  within control pin slot  36 . Loosening control pin knob  34  allows decline control pin  30  to be repositioned within slot  36 , thus varying the relation of decline control pin  30  to support frame  16  as well as decline control slot  28 . This in turn varies the operable decline angle range of reclinable chair  8  by virtue of the connection of trailing arm  24  to point  26  of reclinable chair  8 . 
     Although one embodiment of a decline control mechanism  22  having a decline control pin  30 , trailing arm  24 , and mounting bracket  32  with control pin slot  36  has been illustrated, it will be understood with benefit of this disclosure that any other method or mechanism suitable for limiting the operable decline angle range of a reclinable chair  8  may be employed. For example, a decline control pin may be fixably attached to a support frame  16  or alternatively may be adjustable or repositionable in relation to a support frame  16  by means other than a control pin adjustment slot  36  including, but not limited to, by multiple mounting holes for receiving a decline control pin in multiple locations. 
     As shown in further detail in FIG. 4, a decline control mechanism  22  may also include a decline resistance control mechanism, in this exemplary embodiment a friction control mechanism including a brake control wheel  40  and brake surfaces  42  and  46 . It will be understood that decline control resistance refers to application of resistance to both declining motion that increases the angle of decline, as well as the opposite return or inclining motion that decreases the angle of decline. Brake control wheel  40  and brake surfaces  42  and  46  are threadably received on decline control pin  30  so that rotation of the brake control wheel  40  causes brake surfaces  42  and  46  to contact trailing arm  24  and frictionally resist sliding movement of decline slot  28  of trailing arm  24  about decline pin  30 . Trailing arm  24  may be any material suitably strong or rigid enough for controlling changes in decline angle  11  during exercise by a user (such as steel, plastic, aluminum, etc.). Brake surfaces  42  and  46  may be any material suitable for frictionally interacting with trailing arm  24  to control resistance to changes in decline angle  11  including, but not limited to, plastic, metal, rubber, etc. In one embodiment trailing arm  24  is steel and brake surfaces  42  and  46  are injection molded plastic. 
     Advantageously, in one embodiment the adjustment of brake control wheel  40  allows a user to selectively control resistance to adjustment or change in the angle of decline  11  during exercise, from virtually no resistance to almost complete resistance to changes in angle of decline  11 . Further, in this embodiment brake control wheel  40  may be sufficiently rotated so as to provide sufficient friction via brake surfaces  42  and  46  to completely prevent movement of trailing arm  24  relative to pin  30 , thus preventing adjustment of, or change in, the angle of decline  11 . Thus, a user is provided with complete control over the exercise process, and may selectively prevent or resist such adjustment at any time. When performing back extension exercises, for example, a new user or beginner may wish to use brake control wheel  40  to impart sufficient friction or resistance so that backrest  10  gently descends. More experienced users may wish to perform the same exercises with control wheel  40  set to provide little or no such friction or resistance. Advanced users may impart sufficient friction during abdominal flexion exercises to increase workload during workout. 
     As shown in FIG. 4, a decline resistance control mechanism may be operably secured to support frame  16  via bracket  32  and to trailing arm  24  via decline control pin  30 , control pin knob  34  and control pin fastener  44 . Brake surfaces  42  and  46  are positioned on opposite sides of trailing arm  24  to slidably and frictionally contact trailing arm  24 . 
     It will be understood with benefit of disclosure by those of skill in the art that although one exemplary embodiment of a decline control mechanism  22  has been illustrated in the figures, other configurations and combinations of features are possible. For example, the disclosed exercise device may be configured with a decline control mechanism having only a mechanism to adjustable control operable decline angle range, such as provided by decline control pin  30 , mounting bracket  32  and control knob  34 . Alternatively, a decline control mechanism  22  including only a friction control mechanism may be provided. In still other embodiments, it is possible to provide a mechanism to only control maximum and minimum decline angle (i.e., a single operable decline angle range), such as would be the case with only a trailing arm  24  and stationary decline control pin  30 . In any case, those of skill in the art will understand with benefit of this disclosure that such features may be combined or varied to achieve the desired amount of control for specific users and applications. 
     FIGS. 5 and 6 provide additional illustration of one exemplary embodiment of decline control mechanism  22 . In this regard, FIG. 5 shows a side view of the components of decline control mechanism  22  described above. Also shown in FIG. 5 are optional inscribed position indicators, in this case indicating three positions for decline control pin  30 . Indicator  38  is designed to interface with these inscriptions so that the user knows which position has been selected. In the illustrated embodiment FIG. 5, position  1  allows backrest  10  to descend in relation to seat  12  to a point where backrest  10  and seat  12  together form a surface which is essentially flat, corresponding to a decline angle of about 180°. Position  2  allows further descent so as to provide a extension of a user&#39;s back, in this case a decline angle of about 215°. Selection of position  3  allows a maximum decline angle of about 235°. The corresponding operable decline angle ranges for the three positions are, respectively, from about 65° to about 180°, from about 65° to about 215°, and from about 65° to about 235°. 
     It will be understood with benefit of this disclosure that other optional features and combinations of features may be advantageously employed as so desired. For example, the illustrated embodiment may also employ an optional vertical support bar  50 , handgrips  52  and  58 , and footrest  54 . Support bar  50  is shown pivotally attached to support frame  16  so that it may be alternately stowed in a horizontal position in storage bracket  56  or selectively deployed vertically so as to receive and statically support backrest  10  in horizontal position, i.e., corresponding to a decline angle of about 180°. Advantageously, vertical support bar  50  thus may be used to provide additional support (for example, in conjunction with brake control  40 ) when it is desired to use reclinable chair  8  as a static flat surface, for example, as a static workout bench for weight lifting or other exercises. In this regard, FIG. 2 shows vertical support bar  50  in stored position. FIG. 6 shows vertical support bar  50  in deployed vertical position and ready to receive and support backrest  10 . FIG. 3 shows reclinable chair  8  in flat position and statically supported by vertical support bar  50 . Shown in FIG. 8 is vertical support bar attachment point  70  on the underside of backrest  10 . Vertical support bar attachment point  70  removably receives vertical support bar  50  and removably secures support bar  50  via spring-loaded locking retaining knob (or “pop-pin”)  72  which is received in a hole provided in support bar  50 . 
     As illustrated, support frame handgrips  58  may be provided on support frame  16  as shown in FIGS. 1-3 and  6 - 8 , and may be, for example, foam padding or other suitable handgrip material surrounding tubular frame of support frame  16 . In this configuration, handgrips  58  on either side of seat  12  may be employed by the user during the exercise to control the user&#39;s body movement. In this regard, a user may use handgrip  58  to help push and pull themselves through the full range of movement (or through the full selected operable decline angle range), as shown in FIGS. 9 and 10. As further illustrated, optional handgrip areas  52  may be provided for use during exercising such as shown in FIGS. 12 and 13, thus providing a user with alternate positions for performing, for example, more advanced exercises and/or abdominal exercises such as crunches. Handgrips  52  are shown positioned on opposite sides of backrest  10  and may be grasped on either side of a user&#39;s head during exercise. As such, handgrips  52  may allow a user&#39;s arm strength to compensate or assist other weak muscles by pulling on the handgrips  52 . It will be understood, however, that neither handgrips  52  nor  58  are necessary for performing exercises using the disclosed exercise device. Handgrips  52  may or may not be padded (such as with foam or other suitable handgrip material). It will be understood with benefit of this disclosure that the configuration and location of handgrips  52  and/or  58  may be varied in a number of ways, for example a single overhead bar may be attached on top of backrest  10  in addition to or instead of separate handgrips  52 . 
     Also illustrated is optional footrest  54 . In this case, footrest  54  is slidably adjustable inwards and outwards by means of position holes  62  and pop-pins  64 . Footrest  54  provides support for a user&#39;s feet during extension exercises as shown in FIG.  13 . However, it will be understood with benefit of this disclosure that footrest  54  is not necessary and the exercises may be performed with the user&#39;s feet on a floor surface  200  instead, as shown in FIGS. 9-12. Furthermore, it will be understood that a footrest need not be adjustable and may have different configurations suitable for supporting a user&#39;s feet during exercise. A footrest may or may not be padded or provided with a non-skid surface such as rubber, etc. 
     Other optional features which may be advantageously employed include a lumbar support structure  80  for providing supplemental support to the back of a user during exercise. As may be seen in the figures, lumbar support structure  80  may be configured as a raised area within backrest  10  for providing additional support to the lumbar area of a user during exercise. Those of skill in the art will understand with benefit of this disclosure that a lumbar support structure  80  may be configured in different sizes and shapes known in the art. In one embodiment, lumbar support structure may be a thickened area of foam padding within a foam padded backrest as described elsewhere herein, although any other material suitable for supporting a user&#39;s back may be employed (including a solid insert in a padded backrest, a shaped raised area in a molded plastic backrest, etc.). 
     Other optional features include optional support frame wheels  90  which may be provided for ease of transportation or movement of the disclosed exercise device by one person. With benefit of this disclosure such wheels may be of any configuration (or alternatively may be skids, for example) known in the art and suitable for transporting the disclosed exercise device. 
     FIGS. 9-13 illustrate a user  100  in exercise position on declinable chair  8 . As illustrated, the head, upper and lower back of user  100  are in contact with and supported by backrest  10 . The buttocks and thighs (or posterior of user  100 ) are in contact and is supported by seat  12 . Optional lumbar support area  80  is positioned to be in contact with the user&#39;s lower back. FIG. 9 shows user  100  in a seated position in declinable chair  8 . 
     FIGS. 9-11 illustrate one exemplary embodiment of back extension exercises which may be performed using the disclosed declinable chair  8  by user  100 . As shown in FIG. 9, user  100  may begin in a seated position in declinable chair  8 , the angle of decline of declinable chair  8  being about 65°. If so desired, when a user mounts the device, the decline angle may be locked in seated position using decline control mechanism  22  (when present) to make mounting easier. Although FIG. 9 shows a user  100  in seated position on a declinable chair  8  having an angle of decline of about 65°, it will be understood with benefit of this disclosure that a decline angle of chair  8  may vary and be greater than or less than about 65° when a user  100  is in seated position, depending on configuration of declinable chair and/or body characteristics of a specific user. As shown in FIGS. 9-11, for back extension exercises hands  102  of user  100  are typically positioned such that the arms and hands of user  100  do not play a significant role in the exercise motion, thus giving muscles of the lower back a greater workout. As shown in FIGS. 9-11, feet  104  of user  100  may be positioned on a floor surface  200  for support during back extension exercises, although feet  104  may alternately be positioned on footrest  54  so as to further workout the muscles of the lower back, typically by more experienced users. When feet  104  are positioned on the floor, user  100  may “walk” them out and away from the device while pushing backwards on backrest  10 , as shown in the figures. 
     To effect back exercises, user  100  may utilize lumbar muscles of the lower back to pivot backrest  10  in relation to seat  12  so as to increase the angle of decline as illustrated in FIGS. 10 and 11. This may be accomplished, for example, by gradually releasing decline control mechanism  22  (when present and in initially locked position) and pushing backwards. In this regard, FIG. 10 illustrates user  100  on declinable chair  8  which has been pivoted by the back muscles of user  100  to an angle of decline of about 180°. Using one embodiment of the disclosed device, a user  100  may adjust resistance to change in angle of decline during such pivoting motion using, for example, a decline control mechanism  22  as described elsewhere herein. 
     In one exemplary embodiment for using the disclosed device, user  100  may begin back extension exercises with hands  102  on hand grips  58  and feet  104  on a floor surface  200 . User  100  maintains hands  102  on grips  58  as backrest  10  descends from seated starting position to a relatively flat position (or about 180°) as shown in FIGS. 9 and 10, “walking” feet  104  outward from the device as this occurs. User  100  then may stretch their arms behind their head as backrest  10  further descends to extend the spine (as shown in FIG.  11 ). The maximum decline angle may be held for a period of time (such as about 20-30 seconds). User  100  may then position hands  102  on handgrips  58  while contracting abdominal and buttocks muscles and “walking” feet  104  backward toward the device to cause the angle of decline to decrease to between about 65° and about 180°. This process may be repeated any number of times, as desired. Typically, user  100  does not return to completely to the seated starting position, until finished with the back exercises. 
     FIG. 11 illustrates user  100  on declinable chair  8  in a position having an angle of decline of about 235° and resulting in full or partial extension of the lumbar muscles of user  100 . User  100  may achieve this position by contraction of the lumbar muscles so as to move backrest  10  in relation to seat  12  from the 180° to the 235° angle of decline illustrated in FIG.  11 . 
     To complete a back extension exercise, user  100  may contract abdominal muscles so as to push the buttocks downward and pivot backrest  10  relative to seat  12  in a manner essentially reverse or opposite to that previously described in relation to FIGS. 9-11. 
     Although an angle of decline of about 235° is illustrated in FIG. 11, it will be understood that extension of the spine of a user  100  may be achieved with any maximum angle of decline that results in bending of the spine backwards through contraction of the lumbar extensor muscles, including maximum angles of decline greater than or less than 235°. It will also be understood that benefits of the disclosed exercise device may be achieved by a user without extension of the spine, for example, in embodiments is having a maximum angle of decline of about 180° or less. For example, using one embodiment of the disclosed device, one or more different maximum decline angles may be selected by a user by use of decline control mechanism  22  as described elsewhere herein. In this regard, it will be understood that decline control mechanism  22  and/or other components of a declinable chair  8  may be configured to achieve maximum decline angle of greater than or less than about 235°, as so desired. In another possible embodiment, a device may be constructed to have a non-adjustable maximum angle of decline of predetermined value. 
     As illustrated and described above, back extension exercises may be performed with little, if any, assistance from hands and arms of a user. This is true when pivoting declinable chair  8  in a direction increasing the angle of decline, and/or when moving pivoting chair  8  in the opposite direction to decrease the angle of decline. In this way, during exercise the muscles of the lower back perform the majority of the work, and therefore receive most of the benefits of the exercise. However, it will be understood with benefit of this disclosure that any amount of assistance may be provided by a user&#39;s arms or hands, for example, by gripping optional hand grips  52  and/or optional support frame handgrips  58  during back extension exercise. 
     Also as described above, feet  104  of a user  100  may be placed on optional footrest  54  throughout the exercise so that lower back muscles of a user  100  are primarily responsible for substantially all of the movement of declinable chair  8  throughout the reciprocating angles of decline during back extension exercises. In this regard, since more strength is required from the back muscles when feet  104  are placed on footrest  54  during exercise, footrest  54  is typically used by more experienced and/or stronger users. 
     FIGS. 12 and 13 illustrate a user  100  in exercise position on a declinable chair  8  with hands  102  gripping handgrips  52  for assistance during exercise, for example, when performing sit-ups or abdominal crunches. In FIG. 13, feet  104  of user  100  are shown placed on footrest  54 . In FIG. 12, feet  104  of user  100  are shown in contact with a floor surface  200  for support. Thus, it may be seen that a user  100  may avail themselves of, and/or vary, any combination of footrest  54 , handgrips  102 , and/or support frame handgrips  58  during exercise. Advantageously, by varying position of the hands and feet, as well as by varying resistance to change in decline angle (using, for example, decline control mechanism  22 ), a user may tailor exercises to address particular muscle groups such as the abdominals, obliques, and/or lower back. 
     For example, looking to FIGS. 12 and 13, it may be seen that by varying the amount of pull or force exerted by the arms of user  100  through hands  102  to handgrips  52 , user  100  may control how much of the exercise motion is caused by the lumbar muscles of the lower back versus the abdominal muscles. In addition, user  100  may concurrently increase resistance to change in decline angle utilizing decline control mechanism  22  in a manner as previously described herein. Should user  100  wish to focus exercise motion on the abdominal muscles rather than the muscles of the lower back, more force may be exerted by user  100  through the arms and hands  102  on handgrips  52 . To work the abdominal muscles even more, decline control mechanism  22  may be adjusted so as to offer increased resistance and changes in decline angle. 
     Advantageously, the disclosed device may be utilized to perform a variety of different exercises, including variations on exercises described herein as well as additional exercises not described. For example, abdominal “crunch” exercises may be performed on one embodiment of the disclosed device as follows. A maximum decline angle of about 180° may be selected, for example, using control pin knob  34  of decline control mechanism  22 . Reclinable chair  8  may be locked in seated position for mounting, for example, using brake control wheel  40 . User  100  may then sit on reclinable chair  8  with the back of user  100  against backrest  10  and with feet  104  flat on the floor in front of user  100 . User  100  may then release brake control wheel  40  with one hand while holding onto handgrips  52  with the other hand, and “walk” feet  104  out while allowing backrest  10  to descend in a controlled manner. Then, to perform a crunch, user  100  may tighten the buttocks and contract the abdominal muscles, lifting the body and the backrest to a comfortable height (usually not fully upright) as shown in FIG.  13 . This raised position may be held using the abdominal contraction for a period of time (such as 3 seconds or more), before allowing backrest  10  to descend and repeating the process. 
     A “knee up” crunch exercise may be performed in essentially the same manner as described above for a crunch, with the exception that user  100  places feet  104  on foot rest  54  during the exercise, and brings one knee toward the chest when backrest  10  is raised during the abdominal contraction. The knee is lowered each time the backrest  10  descends, and may be alternated with the other knee from repetition to repetition. 
     Side lateral extension exercises may be performed by a user  100  while lying on their side with one shoulder against backrest  10  and while grasping handgrip  52  with hand  102  closest to backrest  10 . A user  100  may mount declinable chair  8  in such a position with the angle of decline locked at, for example, about 215°. The angle of decline may be locked in this manner, for example, using brake control wheel  40  of decline control mechanism  22  (when present). Once in position, user  100  may slowly press their upper body against backrest  10  while releasing brake control wheel  40  to cause backrest  10  to descend. As backrest  10  descends, the hips of user  100  will tend to shift upward. Once backrest  10  has descended to a desired preset maximum angle of decline (set, for example, using control pin knob  34 ), user  100  may extend their free arm up and over their head, typically holding this position for a period of time (such as 20 to 30 seconds). User  100  may then return their free arm to their side and repeat the stretch exercise again on the same side or by rolling over and repeating the exercise on the other side. 
     In another exemplary embodiment, prone extension exercises may be performed. Prior to beginning exercise, user  100  may select a desired preset maximum angle of decline, for example, an angle of decline greater than about 180°. Such an angle may be set, for example, using control pin knob  34  of decline control mechanism  22  (when present). The declinable chair is then locked in this maximum decline angle position (such as by using brake control wheel  40 ) for mounting of the device by user  100 . User  100  may then mount declinable chair  8  in a position facing chair  8  and grasp side handgrips  58  with both hands, gradually kneeling with both knees on the seat and lowering themselves to lie face down on declinable chair  8  so that the hips of user  8  are positioned over pivot point  20  of declinable chair  8 . The next movement of this exercise may be performed with hands  102  on a floor surface  200  beside the backrest  10  if so desired. User  100  may then release brake control wheel  40  to allow declinable angle  11  of declinable chair  8  to decrease. User  100  may then gently contract their lower back muscles so that the body of user  100  rises to a substantially flat position, using their arms and hands  102  against the floor surface  200  if necessary to help push themselves upwards. This position may be held for a period of time (such as about 30 seconds). User  100  may then return to the starting position in a slow and controlled manner, and repeat this process a number of times as desired. 
     Other exercises that may be performed using the disclosed exercise device include, but are not limited to, exercises performed on reclinable chair  8  when decline angle is locked in substantially flat position, or at about 180°, as described elsewhere herein. A few examples of such exercises include chest presses, chest flys, pullovers, dumbbell rows, tricep kickbacks, seated bicep curls, etc. 
     In one exemplary embodiment illustrated in FIG. 17, the disclosed exercise device may be configured to have a declinable chair  8  which may be pivoted by a user  100  from a seated position (such as that shown in FIG. 9) to a position of greater decline angle (such as that shown in FIG. 11) in a smooth and fluid movement, and which also has a tendency or propensity to return to the seated position with relatively little resistance. When so configured, a user  100  may advantageously return to the seated position by, for example, grabbing support frame handgrips  58  (as illustrated in FIG. 10 ) and slightly pulling on arm grips  58  so as to initiate downward pivoting of declinable chair  8 , and downward movement of the lower back of a user  100 , so that declinable chair  8  returns to the initial starting position of FIG.  9 . Although resistance of pivoting motion of declinable chair  8  may be controlled using decline control mechanism  22 , it will be understood that absent such additional resistance, only minimal resistance exists in this embodiment and declinable chair  8  has a natural propensity to return to a seated position. Such a propensity is advantageous as it allows a beginning or injured user to perform extension exercises with minimum strain on the muscles of the lower back. It will be understood, however, that such a propensity to return to seated position is an optional feature, and need not be present. 
     Although minimal resistance to change in decline angle and propensity to return to seated position may be imparted using active mechanisms (such as springs, rubberbands, etc.), it may also be advantageously achieved by the design and interrelation of support frame  16  and declinable chair  8 . In this regard, declinable chair  8  may be dimensioned and interrelated as illustrated in the figures to achieve a smooth fluid movement of declinable chair  8  throughout varying angles of decline, as well as an ease of motion as declinable chair  8  pivots and returns to the seated position. 
     For example, referring to the exemplary embodiment illustrated in FIGS. 14-16, pivot points  18  and  20  may be located on support frame  16  so as to be positioned about 8″ and about 11″, respectively, above a floor surface  200  when frame  16  is positioned on floor surface  200 . In this embodiment, pivot points  18  and  20  may be horizontally spaced apart by about 18.5 inches, as indicated by the total of the distances marked “X” and “Y” on FIGS. 14-16. In this embodiment, as shown in FIG. 14, chair  8  may be configured and attached to support frame  16  so that chair pivot point  14  is spaced in a horizontal direction from backrest pivot point  20  by an “X” distance of about 3.5 inches and spaced in a horizontal direction from seat pivot point  18  by a “Y” distance of about 15 inches when chair  8  is in a position with an angle of decline of about 65°. In this position chair pivot point  14  is located about 4 inches above floor surface  200 . In the same embodiment, as shown in FIG. 15, pivot point  14  is spaced in a horizontal direction from backrest pivot point  20  by an “X” distance of about 7.5 inches and spaced in a horizontal direction from seat pivot point  18  by a “Y” distance of about  11  inches when chair  8  is in a position with an angle of decline of about 180°. In this position chair pivot point  14  is located about 10.5 inches above floor surface  200 . In the same embodiment, as shown in FIG. 16, chair pivot point  14  is spaced horizontally from backrest pivot point  20  by an “X” distance of about 6.5 inches and spaced in a horizontal direction from seat pivot point  18  by a “Y” distance of about 12 inches when chair is in a position with an angle of decline of about 235°. In this position chair pivot point  14  is located about 14.5 inches above floor surface  200 . 
     Although particular and exemplary embodiments of the disclosed exercise device and exercises performed thereon have been described and illustrated herein, it will be understood with benefit of this disclosure by those of skill in the art that various modifications in limits and resistance to changes of angle of decline, as well as various positions of a user&#39;s body, feet and hands in a variety of ways so as to achieve varying degrees of exercise (such as to suit a particular individual), as well as to focus on different muscle groups, e.g., the lower back, abdominals and obliques. 
     While the invention may be adaptable to various modifications and alternative forms, specific embodiments have been shown by way of example and described herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims. Moreover, the different aspect of the disclosed methods and apparatus may be utilized in various combinations and/or independently. Thus, the invention is not limited to only those combinations shown herein, but rather may include other combinations.