Patent Publication Number: US-7585263-B2

Title: Abdominal exercise machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/741,104, filed Nov. 30, 2005, and is a continuation-in-part of U.S. application Ser. No. 11/607,745 filed Nov. 30, 2006 now U.S. Pat. No. 7,455,633, which is a continuation-in-part of U.S. application Ser. No. 11/030,420 filed Jan. 5, 2005, now U.S. Pat. No. 7,232,404, which references are incorporated here by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to exercise machines for abdominal muscles and more, particularly to exercise machines in which the lower legs are supported by a leg support that utilizes a rolling, gliding, or sliding mechanism. 
     2. Description of Related Art 
     Traditional abdominal exercises, such as sit-ups are known to cause overload to the spine and neck and can easily cause injury when sitting up from a prone position to a sitting position. To correct this problem, many devices and exercises have been created in an attempt to develop and maintain the abdominal muscles. Unfortunately these devices and exercises often produce results which do not necessarily strengthen the abdominal muscles but strengthen the hip and thigh muscles attached to the lumbar spine area and to the rear of the pelvis and hip bones. When such muscles contract not only does the rectus muscle of the abdomen work with little effort but the other muscles rotate the pelvis forward thus creating the occurrence of increased lower back pain which contributes to poor mechanical alignment and undesirable upright posture of the exerciser. 
     For example, abdominal exercises that use arm slings and the person hanging from a bar are only beneficial to advanced athletes that are able to perform the exercise effectively. However, even when performed effectively, the back is extremely overloaded and the hip-flexors handle much of the load creating a risk of injury. 
     Also, lower abdominal exercises utilizing leg raises or reverse crunches where the knees are raised to the chest while the body is suspended vertically, supported only by arms or elbows, are strenuous on the lower back and offer minimal back support. These types of exercises are especially bad due to excessive strain on the back caused by lifting the knees to the chest. Furthermore, a significant number of people who do this type of abdominal exercise become injured with continued use. 
     Also, some exercise machines concentrate on cardio training with too little resistance thereby producing semi-effective strength training with very limited results. For example, exercise machines similar to the AB LOUNGE or AB SCISSOR provide more isolation than the above abdominal exercise but do not provide enough resistance because the exercise motions performed with these devices do not provide a resistance that is consistent with strength training. 
     In addition, exercise machines similar to the AB DOLLEY or AB SLIDE are effective for upper abdominal muscles and upper torso but not for lower abdominals. Also, exercises using these types of devices are difficult and dangerous for two reasons: first resistance is concentrated downward by gravity making isolation on the abdominal muscles impossible, as the entire upper torso, front and back muscles, and arms are needed to handle the load; and second, the user&#39;s back is forced into an ergonomically unfriendly angle with the upper body which is operating too low in conjunction with the lower body. Such a position is uncomfortable, awkward and can cause injury. 
     What is needed is an abdominal exerciser that will isolate the upper and lower abdominal muscles with true strength conditioning to change the shape of the overall abdomen muscle structure without compromising safety or support for the back. It would be beneficial if the apparatus could enable a user to execute the abdominal exercise in a biometrically neutral position, minimizing or eliminating back and neck strain. It would also be beneficial if the user could perform an upper abdominal crunch simultaneously with a controlled and supported reverse crunch. It would further be beneficial if the apparatus could allow the user to hold either the upper or lower crunch in a fully contracted “isometric” position while continuing with the opposite crunch rendering a dynamically concentrated isolation of the abdominal muscles. 
     SUMMARY OF THE INVENTION 
     The abdominal exerciser of the present invention is an exercise device designed to work the abdominal and oblique muscle groups. The abdominal exerciser comprises a carriage that is supported by first and second swing-arms movably connected to a frame. An upper body support is ergonomically positioned and supported by the frame. The first and second swing-arms are non-parallel to each other so that the carriage moves along an arcuate path. 
     To perform the abdominal exercise, a user first positions the forearms on the upper body support and then positions the shins onto the carriage. The user then slides the carriage towards the upper body support by using the abdominal muscles to bring the knees close to the upper body support. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of one embodiment of an abdominal exercise apparatus in accordance with the present invention; 
         FIG. 2  is a front view of an alternate embodiment of an upper body support of an abdominal exercise apparatus in accordance with the present invention; 
         FIG. 3  is a perspective view of an alternate embodiment of an abdominal exercise apparatus in accordance with the present invention; 
         FIG. 4  is a perspective view of the apparatus shown in  FIG. 1  in use by a person; 
         FIG. 5A  is a perspective view of another embodiment in accordance with the present invention; 
         FIG. 5B  is a perspective view of another embodiment in which the upper body support is rotated into a second position; 
         FIG. 6  is a perspective view of another embodiment; 
         FIG. 7A  is a side view of the embodiment of  FIG. 6 ; 
         FIG. 7B  is a side view of the embodiment of  FIG. 6  in use by a person. 
         FIG. 8  is a bottom view of the leg support and track. 
         FIG. 9  is a side view of an embodiment in accordance with the present invention without a track. 
         FIG. 10  is a side view of another embodiment of the present invention without a track. 
     
    
    
     DETAILED DESCRIPTION 
     In the descriptions that follow, like parts are marked throughout the specification and drawings with the same numerals, respectively. The drawing figures are not necessarily drawn to scale and certain figures may be shown in exaggerated or generalized form in the interest of clarity and conciseness. 
     The abdominal exerciser of the present invention isolates the upper and lower abdominal muscles with true strength conditioning to change the shape of the overall abdomen muscle structure without compromising safety or support for the back. It also enables a user to execute the abdominal exercise in a biometrically neutral position, minimizing or eliminating back and neck strain. In one embodiment, the abdominal exerciser of the present invention allows a user to perform an upper abdominal crunch simultaneously with a controlled and supported reverse crunch. Also, it allows a user to hold either the upper or lower crunch in a fully contracted isometric position while continuing with the opposite crunch rendering a dynamically concentrated isolation of the abdominal muscles. 
       FIG. 1  shows one embodiment of abdominal exerciser  102 . Abdominal exerciser  102  has a front portion  132 , rear portion  134  and contains rear support  104 , forward support  106 , track  108 , sled  110 , and upper body support  112 . 
     Rear support  104  rests on the ground and provides foundational support for abdominal exerciser  102 . Rear support  104  may have a long tubular profile, a solid square or rectangular profile, or any other profile known in the art for use as support of a bench like structure similar to abdominal exerciser  102 . Rear support  104  is attached to track  108 . 
     Track  108  can be made of metal, plastic with a metal or TEFLON® coating or some other material that has a relatively low coefficient of friction with the material used to make roller  128 . In the preferred embodiment there are two tracks  108 , however in other embodiments there may be only one track or, alternatively, more than two tracks. Track  108  extends from rear support  104  to forward support  106  and has a rear portion  114  proximate to rear support  104  and a forward portion  116  proximate to forward support  106 . In another preferred embodiment, track  108  can be curved as shown in  FIGS. 5A-5B . The curvature can be circular, ellipsoid, parabolic, or any other curved shape that advantageously affects the abdominal and oblique muscles. 
     In one embodiment the front foundation includes a telescopic extension to raise the height of one end of the track to a desired level of inclination. Forward support  106  elevates forward portion  132  of track  108  at least approximately 6 inches off the ground and contains hollow outer base  118  and adjustable top portion  120  and provides foundational support for abdominal exerciser  102 . Base  118  may have a long tubular profile, a solid square or rectangular profile, or any other profile known in the art for use as support for a bench like structure similar to abdominal exerciser  102 . 
     Adjustable top portion  120  is slidably mounted within outer base  118  in telescoping relation. By sliding the adjustable top portion  120  inwardly or outwardly relative to outer base  118 , the overall length of forward support  106  can be selectively changed to vary the height of forward support  106 . A locking means is provided for locking outer base  118  and adjustable top portion  120  in desired relative positions to create a desired length for forward support  106 . 
     Preferably, the locking means includes at least one hole  129  in outer base  118  and a plurality of holes  130  in adjustable top portion  120  which can be selectively aligned with least one hole  129  in outer base  118 . A pin member is constructed to be inserted in the aligned holes, thereby securely locking forward support  106  in the desired length. At least one hole  129  and holes  130  may be threaded holes, and the pin member may have cooperating threads to enable the pin to be threaded or screwed into the holes to secure forward support  106  at a desired length. Track  108  is secured to forward support  106  and forward support  106  elevates tracks  108  to a desired level, preferably at least approximately 6 inches above to provide an incline. 
     Sled  110  glides along track  108 . Sled  110  contains sled base  126 . Attached to sled base  126  are instep pad  122 , knee pad or leg support  124 , and roller  128 . Roller  128  may be made of metal, plastic with a metal or TEFLON® coating or some other material that has a relatively low coefficient of friction on the material used to make track  108 . In an alternate embodiment, roller  128  may be ball bearings, roller bearings or some other means which would allow sled  110  to travel along track  108  with a relatively low coefficient of friction. 
     Instep pad  122  is made of dense foam, rubber, or some other similar material. The purpose of instep pad  122  is to elevate the feet to avoid interfering with the movement of the sled. Other means may be used to elevate the feet such as a wedge or the feet may not be elevated at all. 
     In one embodiment, knee pad  124  can pivot up to approximately 45 degrees to the right or left of a plane vertical to the center of sled  110 . By pivoting knee pad  124  the oblique muscles can be effectively exercised. 
     Sled  110  can travel the entire length of track  108  but preferably travels to the approximate area of upper body support  112 . 
     Upper body support  112  is attached to front portion  132  of abdominal exerciser  102  and comprises at least one handle  548 . In another embodiment, the upper body support  112  comprises an elevation bar  144  attached to the track  108  and at least one handle  548  attached to the elevation bar  144 . In another embodiment the upper body support can comprise an elevation bar  144 , a cross bar  136 , an arm pad or arm support  138 , and a chest pad or chest support  140 . Elevation bar  144  is attached to track  108  such that sled  110  can travel past elevation bar  144 . In an alternate embodiment, elevation bar  144  is attached to track  108  such that sled  110  cannot travel past elevation bar  144 . In addition, elevation bar  144  may be attached to forward support  106 . Cross bar  136  is pivotally attached to elevation bar  144  and suspend approximately 12 to 48 inches above track  108 . 
     Cross bar  136  is pivotally attached to elevation bars such that the amount of torque required to rotate cross bar  136  can be adjusted, preferably by tension control member  142 . Tension control member  142  controls the amount of resistance required to rotate cross bar  136  and can be set such that cross bar  136  may be locked in any rotational position especially one where arm pad  138  has been rotated towards track  108 . 
     In an alternate embodiment the handles  548  can be pivotally attached to the elevation bar  144  and suspended approximately 12 to approximately 48 inches above the track  108 . 
     Arm pad or arm support  138  is attached to cross bar  136 , has a general rectangular or square profile, and is made of dense foam or some other similar material. Arm pad  138  provides support for the arms during use. Chest pad  140  is attached to arm pad  138  and elevated approximately 1 to 36 inches above arm pad  138 . Chest pad  140  has a general cylindrical, rectangular, or square profile and is made of dense foam or some other similar material. Chest pad  140  provides support for the chest during use. In an alternate embodiment, a head support may be used to support the head. In addition, shoulder pads may be used in conjunction with or to replace chest pad  140 . Other means to support the upper body of the user would be apparent to one skilled in the art. 
     In an alternate embodiment, shown in  FIG. 2 , the cross bar  136  is divided into two sections, right bar section  202  and left bar section  204 . Right bar section  202  and left bar section  204  are pivotally attached to elevation bar  144  such that the torque required to rotate right bar section  202  and left bar section  204  can be adjusted, preferably by a tension control members  206  and/or  208  respectively. Tension control members  206  and  208  controls the amount of resistance required to rotate right bar section  202  and left bar section  204  and can be set such that right bar section  202  and left bar section  204  may be locked in any rotational position especially one where arm pad  138  has been rotated towards the track  108 . Tension control members  206  and  208  have markings or slots such that each one can be set to the same tension as the other or only one tension control member may be used to control the amount of resistance required to rotate the upper body support  112 . 
     The chest pad  140  is also divided into two sections, right pad  210  and left pad  212 . Right pad  210  and left pad  212  are attached to right bar section  202  and left bar section  204  respectively. In an alternate embodiment, chest pad  140  is a single one piece member. 
       FIG. 3  shows an alternate embodiment wherein upper body support  112  is pivoted when sled  110  is accelerated towards upper body support  112 . Near the point of maximum forward motion of the sled, the user has the option to rock the upper body support forward simulating a sit up or what is known as a “crunch” motion. As shown in  FIG. 3 , the pivot means is a bell crank with pivot member  302  attached to elevation bar  144 , lower arm  304  attached to sled  110 , and upper arm  306  attached to upper body support  112 . In use, when sled  110  is accelerated towards upper body support, lower arm  304  pushes pivot member  302  causing it to rotate and pull down on upper arm  306 , which causes upper body support  112  to rotate. A second function of the pivot means is to help accelerate sled  110  towards upper body support  112  by rotating upper body support  112  towards track  108 . 
     Use of a pivot means, such as the bell crank, forces the user to perform an upper abdominal crunch simultaneously with a controlled and supported reverse crunch. As would be known in the art, other means may be used to pivot upper body support  112  when sled  110  is accelerated towards upper body support  112 . For example, other mechanical means similar to a bell crank or a cable and pulley system may be used to pivot upper body support  112  when sled  110  is accelerated towards upper body support  112 . 
     Resistance to sliding the sled is provided by a user&#39;s body weight working against gravity, as it is forced upward on the inclined tracks. Resistance can be increased or decreased by raising and lowering the level of incline. Optionally, a resistance member  310  such as a spring, resistance band, or free weights attached to the sled, may be used for additional resistance. Resistance bands are elastic and attached to rear support  104  and sled  110 . 
     In use, as shown in  FIG. 4 , the forearms are positioned on upper body support  112  and the shins are positioned onto instep pads  122  on sled  110 . Sled  110  is then accelerated towards upper body support  112  by bringing the knees as close as possible to upper body support  112  or the user&#39;s chin while keeping forearms positioned on upper body support  112 . 
     By pivoting knee pad  124  up to approximately 45 degrees to the right or left of a plane vertical to the center of sled  110  the force needed to accelerate sled  110  can be supplied by the right or left oblique muscles. In addition, the knees may be brought as high as possible at the peak of the contracted point of both crunches, rendering a tight squeeze in a near fetal position. 
     To perform an upper body crunch the legs are frozen at a 90 degree angle with respect to knee pad  124  while sled  110  is accelerated towards upper body support  112  and cross bar  136  is pivoted towards track  108 . Then, using the upper abdominal muscles, sled  110  is made to travel back and forth along track  108  while the legs and hips remaining locked at a 90 degree angle with respect to knee pad  124 . 
     To perform a reverse crunch, the knees are allowed to freely move while sled  110  is accelerated towards upper body support  112  but cross bar  136  is not allowed to pivot in any direction. Then, using the lower abdominal muscles, sled  110  is made to travel back and forth along track  108  while cross bar  136  is locked in a desired position. 
     To perform a tandem crunch and exercise both the upper and lower abdominal muscles, the knees are allowed to freely move while sled  110  is accelerated towards upper body support  112  and cross bar  136  is pivoted towards track  108 . Then, the upper and lower abdominal muscles are used to force sled  110  to travel back and forth along track  108  while cross bar  136  is pivoted towards track  108 . 
       FIG. 5A  shows another preferred embodiment of the abdominal exerciser  500  to work the abdominal and oblique muscle groups and isolate the upper and lower abdominal muscles in a biometrically neutral position. The abdominal exerciser  500  can have a rear support  510 , at least one track  520 , a front support  530 , an upper body support  540  and a sled  600  with or without a knee pad or leg support  550 . In a preferred embodiment the track  520  can be an arcuate track  520 . 
       FIG. 5A  shows the arcuate track  520  with a front portion  522  and a back portion  524  where the front portion  522  of the arcuate track  520  is attached to the front support  530  and the back portion  524  of the arcuate track  520  is attached to the rear support  510  such that the front portion  522  is at least approximately 6 inches off the ground. Having the front portion  522  elevated at least 6 inches above the ground is beneficial in a number of ways. For instance, this elevation causes the user to oppose the force of gravity by contracting the abdominal muscles when in the crunch position (see  FIG. 7B ). It also allows the user to exercise in an upright, forward leaning position, much like a bicyclist&#39;s pose. This is convenient and familiar to most users and maintains the user&#39;s upper body in a fixed, still state allowing the user to read or watch a television show during an exercise. 
     The track  520  can be curved as shown in  FIG. 5A . The curvature can be circular, ellipsoid, parabolic, or any other curved shape that advantageously affects the abdominal and oblique muscles. 
     The curved nature of the track  520  allows the user to roll his knees towards his chest (see  FIG. 7B ). It is believed that rolling the knees towards the chest provides for a more effective and safe crunch style abdominal exercise as opposed to the traditional sit up where the person would only pivot at his hips, which could cause injury. Furthermore, the current invention eliminates or minimizes the ability to “cheat” since the entire motion can only be achieved with the abdominal muscles. In the traditional sit-up a person tends to put his hands behind his head pull his head with his arms to facilitate the exercise. This reduces the effectiveness of the exercise as well as creating strain on the neck. In other abdominal exercise devices that also provide for this rolling motion, the user lies on his back, grasps handles then rolls his back into a crunch. However, this again allows for “cheating” as the user could use his arms to facilitate the rolling process. 
     The convex side of the curved track  520  rests on a support surface such as the floor. The track  520  can be curved both at the front portion  522  and the back portion  524 , as shown in  FIG. 5A , or the track can be curved at the front portion  522  only, as shown in  FIGS. 5B ,  6 , and  7 A- 7 B. Having the curvature extend to the back end allows the user to exercise his lower back muscles as well. 
     As shown in  FIG. 8 , the knee pad or leg support  550  can be slidably mounted on the track  520 , and preferably an arcuate track  520 . The sliding mechanism  570  can be a rolling element, such as wheels, a plurality of bearings, such as ball bearings or roller bearings, or a gliding mechanism such as a four bar linkage. Alternatively, the knee pad or leg support  550  can be mounted on the sled  600 , where the sled  600  can be slidably mounted on the track  520 , and preferably an arcuate track,  520  via the aforementioned mechanisms. In a preferred embodiment the leg support  550  can be rotatably mounted to the sled  600 . The leg support  550  can rotate up to approximately 45 degrees to the right or left of a plane vertical to the center of the sled  600 . In other words, the leg support  550  can rotate up to approximately 45 degrees clockwise or counterclockwise about an axis  553  generally perpendicular to the arcuate track  520 . 
     In a more preferred embodiment the leg support  550  can have a first locking member  552  having a first position and a second position. In the first position the first locking member  552 , for example, a lug or pin, disengages the leg support  550 , allowing the leg support  550  to freely rotate about an axis  553  that is generally perpendicular to the arcuate track  520 . This rotating, pivoting, or swiveling action allows the user to twist his lower body to the left or right while performing an abdominal crunch thereby exercising his left or right oblique abdominal muscles. In the disengaged position the user can alternate exercising his left and right oblique abdominal muscles with each repetition. In the second position the leg support  550  can be locked in a predetermined orientation relative to the sled  600 . This stabilizes the leg support  550  to allow the user to concentrate on the exercise rather than focusing on keeping the leg support  550  in a proper orientation. The leg support  550  can be locked at predetermined positions ranging from zero to about 45 degrees to the right or left of a plane vertical to the center of the sled  600 . In some versions the locking member is a retractable lug member, pop pin, or pin and yoke configuration. 
     If the user wants the leg support  550  to be fixed at a particular angle during the exercise, whether the angle is parallel to the track, 45 degrees oblique to the track, or any angle in between, the user simply rotates the leg support  550  to the desired angle and moves the lug or pin  552  into the engaged position by inserting it into an indentation or recess  852  in the engagement surface. Although  FIG. 8  shows one indentation or recess  852  there can be a plurality of indentations or recesses  852 . As such, the engagement surface of receptor block or yoke comprises a plurality of recesses  852 , where each recess  852  is shaped to accept the lug or pin member  552 . In the illustrated embodiment, the lug  552  is spring activated, and releasing the lever causes a compression spring (not shown) to force the lug down towards the engagement surface. 
     Other pin and yoke configurations are equally contemplated, however, within the present invention, including a cog and sprocket arrangement, or alternatively, a threaded pin that requires the user to press the pin into the desired hole, which is tapped with mating threads, and requires twisting the pin into the engaged position in the hole in order to lock the leg support  550  into a desired orientation. The pin and yoke combination could also be replaced with a mechanism comprising engaging teeth, such as a pawl and ratchet wheel, or other such clutch mechanism or one or many clamping configurations such as a tightening strap and tactile contact surface, or the like. With such alternatives, the allowable angular positions of the leg support  550  may be discreet positions (such as with a pin and hole combination) or may be continuous (such as with other common clamping configurations). As a result, the leg support  550  may be freely pivoted about the pivot axis during an exercise, adding to the diversity of abdominal muscle exercises that can be performed. For example, the lug may be removed from the surface and withheld from engaging any of the recesses  852  in the surface either by moving the lug to a plane offset from the recesses  852  or by retaining the lug in the disengaged position so that it is held away from the surface itself during the exercise. 
     To move the leg support  550  in such a way, the user would release the first locking member  552  from an engaged position to a disengaged position before an exercise to allow the leg support  550  to pivot about a pivot axis, in which the leg support  550  can be locked at any one of a plurality of angles relative to a plane vertical to the center of the sled  600  based on the desired exercise such as in  FIG. 8 . 
     The knee pad or leg support  550  can be designed to provide a more supportive and more stylish leg support  550 . For example, the knee end can be indented and the ankle end can be raised so as to conform to the contours of the front portion of the average leg. 
     The upper body support  540  is fixedly mounted in relation to the track  520 , and preferably an arcuate track  520 . Having the upper body support  540  fixed allows the user to stabilize the upper body and focus the exercise on the abdominal muscles as shown in  FIG. 7B . In addition to providing a more effective crunch, having the upper body support  540  fixed facilitates the user to engaging in other cognitive activities such as reading, watching television, or conversing with others. The upper body support  540  can have an elevation bar  542 , a cross bar  544 , and at least one arm pad or arm support  546 . In another embodiment the upper body support  540  can have at least one handle  548  for the user to grasp during the exercise. The upper body support  540  can also have at least one chest pad and at least one head pad. 
     The upper body support  540  can have a second locking member  549  for selectively adjusting the height of the upper body support  540 . In a preferred embodiment the second locking member  549  for selectively adjusting the height of the upper body support  540  can be on the elevation bar  542 . The second locking member  549 , such as a pop pin or any other locking member described previously, can be disengaged from the front support  530  to allow the upper body support  540  to slide up or down to a desired height, then the locking member can be re-engaged to lock the upper body support  540  in place at the desired height. The elevation bar  542  can be cylindrical in shape to provide a means for rotating the upper body support  540  without having to remove the elevation bar  542  from the front support  530 . The elevation bar  542  can further have recesses on opposite sides such that the upper body support  540  can be arranged in at least two different orientations. 
     As shown in  FIG. 5B , the upper body support  540  can be pivotally attached to the front portion  522  of the track  520 , and preferably an arcuate track  520 . In a preferred embodiment the cross bar  544  of the upper body support  540  can be pivotally attached to the elevation bar  542  and suspended approximately 12 to approximately 48 inches above the arcuate track  520 . The embodiments illustrated in  FIGS. 5A and 5B  show two such mechanisms for providing this adjustability of the upper body support  540 , but other telescoping and gear mechanisms are equally contemplated and within the scope of the present invention. 
     Having the upper body support  540  pivotally attached to the front portion  522  of the arcuate track  520  or the elevation bar  542  allows the handles  548  to pivot from a first position to at least a second position to perform a different type of exercise or isolate a different abdominal muscle group. For example, in a first position the handles  548  can be above the track, in front of the arm pad  546  so that the user can grasp the handles  548  with his knuckles facing forward while resting his upper body on the arm pad  546  (see  FIGS. 7A and 7B ). In a second position the upper body support  540  can be rotated 180 degrees about an axis protruding up from the front support  530  and then tilted slightly downward by pivoting the upper body support  540  downward about an axis perpendicular to the front support  530  and to the arcuate tracks  520  so that when the user grasps the handles  548  his arms and elbows are tucked in near his rib cage with his knuckles facing a downward direction (see  FIG. 5B ). Alternatively, the upper body can be placed in a second position by pivoting the handles  548  downward 180 degrees and rotating the upper body support  540  about an axis protruding from the longitudinal direction of the cross bar  544 . 
     To provide for a means for pivoting, the upper body support  540  or cross bar  544  can be detachably coupled to the elevation bar  542  with recesses for receiving a locking member on opposite sides such that the upper body support  540  can be rotated 180 degrees and locked back into the elevation bar  542  in a new orientation. Alternatively, the elevation bar  542  can be cylindrical such that when the locking member is disengaged, the upper body support  540  can be rotated into a new orientation without having to remove the upper body support  540  from the front support  530 . In another embodiment the upper body support  540  can be pivotally coupled to the elevation bar  542  via any number of common pivot connections, such as a ball and socket or toothed mechanism. The downward rotation of the upper body support  540  can be accomplished with a variety of hinge-like mechanisms. 
     The arm pad  546  can be removable so as not to cause interference with the normal use of the exercise device, particularly when the handles  548  of the exercise device are in the lowered position (see  FIG. 5B ). The elbow portion of the arm pad  546  can be raised to prevent slippage during the exercise. 
     As shown in  FIG. 6 , the abdominal exercise machine  500  can further comprise a resistive or resistance member  560  to increase the resistance required to move the sled  600  or the leg support  550 . The resistance member  560  can be on the leg support  550 , the sled  600 , or the track  520 , and preferably an arcuate track  520 . The resistance member  560  can be weights, elastomer members, spring members, viscous members, pneumatic members, or any other means to increase the force required to move the sled  600  along the track. For example, the leg support  550  or sled  600  can have a protrusion  554  to which weights can be added. Alternatively, one end of an elastomer, spring, or pneumatic member can be attached to the protrusion  554  and the other end of the elastomer, spring or pneumatic member can be attached to the front portion  522  or rear support  510 . The degree of resistance can be changed by adding more weights, elastomer members, or spring members or by selecting heavier weights, elastomer members with lower elasticity, spring members with higher tension, pneumatic members with higher pressure or any combination thereof. 
     Both the front support  530  and rear support  510  can each further comprise a third and fourth locking members  532  for selectively adjusting the height of the front portion  522  or back portion  524  of the track  520 , and preferably an arcuate track  520 , respectively (see  FIG. 5A ). The third and fourth locking members  532 , such as a pop pin or any other locking member described previously, can be disengaged from the front support  530  or rear support  510  to allow the front support  530  or rear support  510  to slide up or down to a desired height, then the third and fourth locking members  532  can be re-engaged to lock the front support  530  or rear support  510  in place at the desired height. 
       FIGS. 7A and 7B  show the abdominal exerciser further comprising a stabilizing bar  700 . The stabilizing bar  700  can be pivotally coupled to the track  520 , and preferably an arcuate track  520 , and detachably coupled to the front support  530 . Furthermore, the front support  530  can be pivotally coupled to the arcuate track  520 . This provides a means for folding up the exercise machine  500  when not in use. When a user has completed his exercise he can detach the stabilizing bar  700  from the front support  530  and pivot the stabilizing bar  700  up towards the front portion  522  of the arcuate track  520 . The stabilizing bar  700  can then be attached to the front portion  522  of the arcuate track  520  or the top portion of the front support  530 . In addition, the bottom portion of the front support  530  can be pivoted towards the middle portion of the arcuate track  520  and attached to the middle portion of the arcuate track  520 . 
     In use, as shown in  FIGS. 4 and 7B , abdominal crunches can be accomplished by positioning the body on an abdominal exercise machine  500  and using the abdominal muscles to accelerate the sled  600  from the back portion  524  of the track  520 , and preferably an arcuate track  520 , to the front portion  522  of the track  520  wherein the knees are on the sled  600  and the upper body is on the upper body support  540 , and returning the sled  600  to its original or resting position, thereby completing a repetition. 
     Prior to using the exercise machine  500 , the user must set up the machine  500  to suit the user&#39;s specifications by adjusting the height of the upper body support  540  by disengaging the second locking member  549 , adjusting the upper body support  540  to the desired height, and re-engaging the second locking member  549 . In addition, the height of the track  520  can be adjusted by removing a third and fourth locking member, moving the front portion  522 , the back portion  524 , or both to the desired height, and re-engaging the third and fourth locking member. Also, the user can adjust the positioning of the upper body support  540  by disengaging the second locking member  549 , rotating the upper body support  540  180 degrees about an axis protruding longitudinally from the front support  530 , then tilting the upper body support  540  downward until the handles  548  are in a desired lowered position, such that the elbows are near the ribcage. From this position the user can return the upper body support  540  to the original position by disengaging the second locking member  549 , rotating the upper body support  540  180 degrees, then tilting the upper body support  540  upward until the handles  548  are in the original position such that the elbows are positioned on the arm pad  546  in front of the body. Alternatively, the upper body support  540  can be re-positioned by rotating the handles  548  180 degrees downward, disengaging the second locking member  549 , rotating the upper body support  540  about an axis protruding longitudinally from the cross bar  544 , and re-engaging the second locking member  549  when the handles  548  are in the desired position. 
     Once these preliminary adjustments have been made, the user can perform the exercise by placing the user&#39;s legs or knees on a leg support  550  slidably mounted to at least one track  520 , preferably an arcuate track  520 , placing the user&#39;s arms on an upper body support  540  fixedly mounted in relation to the track  520 , pulling the user&#39;s legs and leg support  550  along the track towards the user&#39;s chin thereby performing a contraction of the user&#39;s abdominal muscles, moving the user&#39;s knees and leg support  550  along the track  520  away from the user&#39;s chin thereby allowing the user&#39;s abdominal muscles to relax and repeating the pulling and moving steps in order to exercise the user&#39;s abdominal muscles. In abdominal exercisers  500  where both the front portion  522  and the back portion  524  of the arcuate track  520  is curved an additional lower back exercise can be performed by including the steps of moving the leg support  550  towards the back portion  524  of the arcuate track  520  thereby contracting the user&#39;s lower back muscles, then moving the user&#39;s knees and leg support  550  along the arcuate track  520  away from the back portion  524  of the arcuate track  520  thereby relaxing the lower back and repeating these steps in order to exercise the lower back muscles. 
     The intensity of the exercise can be modified by adding a resistive or resistance member  560  to the leg support  550 , the sled  600 , or the track  520 , and preferably an arcuate track  520 . The user can select a desired weight, an elastomer member of a desired elasticity, a spring member of a desired tension, a viscous member of a desired viscosity, or a pneumatic member of a desired pressure. If the resistive member  560  is a weight, the user can simply place the weight on a protrusion  554  from the sled  600  or leg support  550 . The user can add a single desired weight or multiple weights to achieve the desired weight. If the resistive member  560  is an elastomer member, a spring member, or a pneumatic member, the user can attach these members to the front or the rear support  530 ,  510  and the sled  600  or leg support  550 . 
     Further steps can include disengaging a leg support  550  by placing a first locking member  552  into a first position and rotating the leg support  550  to one side up to approximately 45 degrees about an axis generally perpendicular to the at least one arcuate track  520 , performing a first repetition, rotating the leg support  550  to the other side up to approximately 45 degrees about an axis generally perpendicular to the at least one arcuate track  520 , performing a second repetition, and repeating a plurality of repetitions while alternating the rotation of the leg support  550  from one side to another in between each repetition to complete a set of abdominal exercises. This allows the user to alternate exercising one oblique then the other during a set of exercises. 
     An alternative step can include locking the leg support  550  in a predetermined position by placing the first locking member  552  into a second position such that the leg support  550  is rotated about an axis that is generally perpendicular to the at least one track, up to 45 degrees oblique from a forward direction, completing a plurality of repetitions to complete a set of abdominal exercises, disengaging the first locking member  552  and rotating and locking the leg support  550  in a second predetermined position, up to 45 degrees oblique from the forward direction, and completing a second plurality of repetitions to complete a second set of abdominal exercises. This allows the user to completely exercise one side of the oblique muscles then switch to exercising the other side. 
       FIG. 9  shows another embodiment of the abdominal exerciser  500  with the arcuate track  520  replaced by a swing configuration comprising a swing frame  902 , at least one swing-arm  906 , a carriage  904 , and an upper body support  540 . 
     The swing frame  902  provides structural support for the swing-arm  906  and may be fixed relative to the upper body support  540 . The swing frame  902  can be mounted to a back leg  912 . In one embodiment, the height of the swing frame  902 , as well as possibly back leg  912 , is adjustable in order to adjust the height or positioning of the carriage relative to the floor or the upper body support  540 . The present invention also contemplates that the swing-arm  906  can also be adjustable or at least be of a predetermined length in order achieve a swing radius within the range of approximately 6 to approximately 70 centimeters. Or more particularly, the length of the swing-arm  906  could be of sufficient length to achieve a swing radius of between approximately 12 and approximately 46 inches. 
     In some embodiments, the swing frame  902  further comprises a horizontal extension bar  918 , wherein the carriage  904  is attached to the horizontal extension bar  918  by the swing-arm  906 . The horizontal extension bar  918  can be adjusted to change the distance between the carriage  904  and the upper body support  540 . In other words, the horizontal extension bar  918  allows for horizontally adjusting the carriage  904 . In some embodiments, the swing frame  902  further comprises a vertical extension bar  920 , wherein the carriage  904  is attached to the vertical extension bar  920  by the swing-arm  908 . The vertical extension bar  920  may be adjustable or telescoping so as to change the height of the carriage  904 . In some embodiments, the vertical extension bar  920  may be movably or pivotably connected to the back leg  912  to adjust both the height of the carriage  904  and the distance between the carriage  904  and the upper body support  540 . In some embodiments, the swing frame  902  comprises both the horizontal extension bar  918  and the vertical extension bar  920 . 
       FIG. 10  shows another alternative embodiment of the abdominal exerciser  500  with the arcuate track  520  replaced by another swing-arm or four-bar linkage mechanism. An abdominal exercise machine  500  utilizing such four-bar linkage mechanism comprises a swing frame  902 , an upper body support  540 , a carriage  904 , a first swing-arm  907 , and a second swing-arm  908 . 
     The swing frame  902  provides structural support for the first and second swing-arms  907  and  908  and the upper body support  540 . The swing frame  902  can further comprise a front leg  910  and a back leg  912 . In another embodiment, the height of the front leg  910  and back leg  912  are separately adjustable. 
     In such an embodiment, first and second swing-arms  907  and  908  are pivotally connected to the swing frame  902  at a frame hinge  914  and pivotally connected to the carriage  904  at a carriage hinge  916 . Additionally, the second swing-arm  908  may be configured either parallel or oblique to the first swing-arm  907 , to create a four-bar linkage system. Pivotally connecting the first and second swing-arms  907  and  908  to the swing frame  902  allows the carriage  904  to swing forward and backward in a plane that is generally parallel to the plane defined by the swing frame  902 . By connecting the first and second swing-arms  907  and  908  to the swing frame  902  and the carriage  904  such that the first swing-arm  907  and the second swing-arm  908  are non-parallel or oblique, the carriage  904  will swing in an arcuate path but not necessarily a circular path. By adjusting the positioning of the first and second swing-arms  907  and  908  and the relative angle therebetween, the user can experience different arcuate paths, including for example, a path similar to the arcuate track  520  of  FIG. 7A  but also other arcuate paths that combine a pivotal element with a horizontal element. Each different arcuate path created thereby can provide a different feel for the user&#39;s knees, legs, and targeted muscle groups. 
     In some embodiments, the swing frame  902  also comprises a first swing-arm slot  922  and a second swing-arm slot  924 , as shown in  FIG. 10 . The first swing-arm slot  922  and the second swing-arm slot  924  provide a degree of freedom for the first swing-arm  907  and the second swing-arm  908 . This degree of freedom increases the range of movement through which the carriage  904  can swing along the arcuate path. In embodiments with first swing-arm slots  922  and second swing-arm slots  924 , the first and second swing-arms  907  and  908  can further comprise a clamping mechanism such that the location of the first swing-arm  907  and the second swing-arm  908  can be fixed. 
     In some of the foregoing embodiments, the carriage  904  may further comprise a leg support rotatably mounted inside the carriage  904 . A rotatable leg support will allow the user to rotate or swivel his or her hips from side to side thereby exercising the oblique abdominal muscles. The leg support may also comprise a locking member to lock the leg support in place. The leg support may further comprise one or more indentations or recesses to accept the locking member so that the leg support can be fixed in a variety of positions ranging from approximately ±45 degrees oblique to the carriage  904  (i.e., left to right). 
     The abdominal exerciser  500  can further comprise a resistance mechanism to increase the resistance required to swing the carriage in an arcuate path. In one embodiment, the resistance mechanism is a weight that can be removably attached to the carriage. In another embodiment, the resistance mechanism can be an elastic or spring tether attached to the sides or bottom of the carriage and a fixed point along the frame. In another embodiment the frame can further comprise a base plate. The tether can be fixedly attached to the base plate directly below the carriage. The tether in the unstretched condition is substantially the same length as the shortest distance from the tether attachment point on the carriage and the tether attachment point on the frame or base plate when the carriage is at rest. Any departure of the carriage from the resting position would stretch the tether, thereby creating resistance. 
     The abdominal exerciser can have different configurations to accommodate users of different sizes and to exercise different abdominal muscle groups, such as the lower abdominals or the upper abdominals, as well as the transverse abdominals or the oblique abdominals. In other words, the distance between the swing frame  902  and the carriage  904  can be adjusted by adjusting the length of the first and second swing-arms  907  and  908 . Providing first and second swing-arms  907  and  908  of the appropriate length will facilitate creating an arcuate path that, when followed, allows movement of the back that follows the natural curvature of the back. This reduces discomfort in the back and reduces potential for back injury. 
     As shown in  FIG. 10 , the frame hinge  914  and the carriage hinge  916  may be removable and the first and second swing-arms  907  and  908  may comprise a plurality of apertures  920 . The frame hinge  914  can be removed from the current aperture  920  and inserted into another aperture  920 , thereby adjusting the height of carriage  904 . Similarly, the carriage hinge  916  can be removed from the aperture  920  and placed in an aperture  920  at a different position to raise or lower the height of the carriage  904 . 
     In another embodiment, the first and second swing-arms  907  and  908  are adjustable by providing first and second swing-arms  907  and  908  of different lengths to accommodate user&#39;s of different sizes or for a single user to isolate the upper or lower abdominal muscle groups. An instructional booklet can be provided to assist the user in determining which length swing-arms would be appropriate for a particular height and a particular muscle group. The instructional booklet can provide a chart so that a user of a particular height desiring to exercise a particular abdominal muscle group can quickly determine which size swing-arms would be recommended. 
     The first and second swing-arms  907  and  908  may be attached to the swing frame  902  and carriage  904  by any attachment mechanism that allows for quick and easy release while providing maximum stability. For example, the swing frame  902  and carriage  902  can be constructed with pins or lugs with a flange on the end protruding away from the frame. The link pins can have key hole slots where at one end of the hole is slight larger than the flange and at the other end the hole narrows to a size just slightly larger than the neck of the lug or pin. The link pin can be attached to the lug by passing the flange through the larger end of the key hole slot then sliding the link pin down so that the smaller hole cannot pass the flange. 
     In another embodiment, a plurality of extensions can be provided. Extensions may be miniature swing-arms that can be connected to the first and second swing-arms  907  and  908  to progressively increase the length of the first and second swing-arms  907  and  908 . 
     In another embodiment, the first and second swing-arms  907  and  908  can be adjustable. For example, the first and second swing-arms  907  and  908  can have an outer sleeve with an inner diameter and an outer diameter and an inner sleeve with an outer diameter substantially the same size as the inner diameter of the outer sleeve to fit inside the outer sleeve. The outer sleeve can have a plurality of holes along its longitudinal axis. The inner sleeve can have a single spring loaded push pin that can fit through the plurality of holes. A user can push in the push pin and insert the inner sleeve into the outer sleeve until the push pin catches a hole that places the carriage at a desired distance from the ground. 
     In another embodiment, the first and second swing-arms  907  and  908  can be attached to the swing frame  902  and carriage  904  with a ball and socket configuration. A ball and socket configuration allows the carriage  904  to swing longitudinally, parallel with the plane of the swing frame  902 , laterally, perpendicular to the plane of the swing frame  902 , and all angles in between the plane parallel with the swing frame  902  and the plane perpendicular to the swing frame  902 . Allowing the carriage  904  to swing laterally will allow the user to further exercise the oblique and transverse abdominal muscle groups. 
     The abdominal exerciser  500  facilitates a method to exercise the abdominal and oblique muscle groups in a biometrically neutral position. The method for exercising the abdominal and oblique muscle groups comprises the steps of pulling the user&#39;s knees along a longitudinal arcuate path towards the user&#39;s chin thereby performing a contraction of the user&#39;s abdominal muscles, such that pulling the user&#39;s knees along the longitudinal arcuate path allows movement of the user&#39;s back to follow the natural curvature of the back; moving the user&#39;s knees along the longitudinal arcuate path away from the user&#39;s chin thereby allowing the user&#39;s abdominal muscles to relax; and repeating the pulling and moving steps in order to exercise the user&#39;s abdominal muscles. 
     Additional steps include immobilizing the upper body by, for example, leaning on an upper body support. In addition, the user&#39;s knees may be placed on a carriage for support. 
     Other additional steps include pulling the user&#39;s knees along a lateral arcuate path in a lateral direction towards a first side of the user&#39;s body thereby performing a contraction of the user&#39;s first oblique and transverse abdominal muscles. Thus, the user can first move the knees in a first lateral direction, thereby contracting the oblique and transverse muscles, then move the knees in the longitudinal direction along the longitudinal arcuate path thereby contracting the rectus abdominous muscles. At this point the user can return the knees back to its original position by either reversing the steps and moving back along the longitudinal arcuate path first, then moving the knees along the lateral arcuate path to reach its original position or by moving the knees laterally in the opposite direction and then moving the knees longitudinally backward to its original position. 
     The exercises can further comprise the step of adding a resistive force to the user by selecting from a group of resistive members consisting of an elastomer member, a spring member, a viscous member, a pneumatic member, and a weight. 
     In using the abdominal exerciser  500 , abdominal exercises can be performed by positioning the body on an abdominal exercise machine  500  and using the abdominal muscles to swing the carriage  904  in a back and forth motion wherein the knees or legs rest on the carriage  904  and the upper body rests on the upper body support  540 . Additional steps include placing a user&#39;s hands on the upper body support  540 ; placing at least portions of the user&#39;s legs on the carriage  904 ; pulling the user&#39;s knees and carriage  904  along a longitudinal arcuate path towards the user&#39;s chin thereby performing a contraction of the user&#39;s abdominal muscles; moving the user&#39;s knees and carriage  904  along the longitudinal arcuate path away from the user&#39;s chin thereby allowing the user&#39;s abdominal muscles to relax; and repeating the pulling and moving steps in order to exercise the user&#39;s abdominal muscles. This type of exercise would primarily exercise the rectus abdominous muscles. 
     Exercising the oblique and transverse abdominal muscles comprises the steps of placing a user&#39;s hands on the upper body support  540  placing at least portions of the user&#39;s legs on the carriage  904 ; pulling the user&#39;s knees and carriage  904  along a lateral arcuate path in a first direction towards a first side of the user&#39;s body thereby performing a contraction of the user&#39;s oblique and transverse abdominal muscles; pulling the user&#39;s knees and knee pad along the lateral arcuate path in a second direction towards a second side of the user&#39;s body thereby performing a contraction of the user&#39;s second oblique and transverse abdominal muscles; and repeating the pulling steps to complete a set of oblique and transverse abdominal muscle exercises. 
     Exercising all the abdominal muscle groups comprises the steps of placing a user&#39;s hands on the upper body support  540 ; placing at least portions of the user&#39;s legs on the carriage  904 ; pulling the user&#39;s knees and carriage  904  along a lateral arcuate path in a first direction towards a first side of the user&#39;s body thereby performing a contraction of the user&#39;s oblique and transverse abdominal muscles; pulling the user&#39;s knees and carriage  904  along a longitudinal arcuate path towards the user&#39;s chin thereby performing a contraction of the user&#39;s abdominal muscles; moving the user&#39;s knees and carriage  904  along the longitudinal arcuate path away from the user&#39;s chin thereby allowing the user&#39;s abdominal muscles to relax; pulling the user&#39;s knees and carriage  904  along the lateral arcuate path in a second direction towards a second side of the user&#39;s body thereby performing a contraction of the user&#39;s second oblique and transverse abdominal muscles; pulling the user&#39;s knees and carriage  904  along the longitudinal arcuate path towards the user&#39;s chin thereby performing a contraction of the user&#39;s abdominal muscles; moving the user&#39;s knees and carriage  904  along the longitudinal arcuate path away from the user&#39;s chin thereby allowing the user&#39;s abdominal muscles to relax; and repeating the pulling and moving steps to complete a set of abdominal muscle exercises. This type of exercise can also be performed by pulling in the knees and carriage  904  along the longitudinal arcuate path then along the lateral arcuate path or any combination thereof. The sequence of steps listed is not intended to limit the scope of the abdominal exercise. It is within the scope of this invention to alter the sequence of steps in any order to provide an exercise regimen that exercises all the abdominal muscles, including the oblique and transverse abdominal muscles. 
     In another embodiment, the user can use his abdominal muscles to move the carriage in a circular motion, either in a clockwise direction, a counterclockwise direction, or a combination of both directions to exercise all the abdominal muscles and even the lower back muscles. 
     Prior to use preliminary adjustments can be made such as adjusting the height of the swing frame  902  for user&#39;s of different size. In addition, the distance between the swing frame  902  and the carriage  904  can be adjusted by altering the length of the first and second swing-arms  907  and  908 , for example, by adding or removing extensions, changing first and second swing-arms  907  and  908  of one size for first and second swing-arms  907  and  908  of another size, telescopically lengthening or shortening the first and second swing-arms  907  and  908 , or attaching the frame hinge  914  and/or the carriage hinge  916  to an aperture  920  at different positions along the first swing-arm  907  and/or the second swing-arm  908 . 
     The intensity of an exercise can be modified by adding a resistive force to the carriage by selecting from a group of resistive members consisting of an elastomer member, a spring member, a viscous member, a pneumatic member, and a weight. 
     Since the swing-arm embodiment of the abdominal exerciser  500  does not require a track, the swing-arm embodiment requires less maintenance since the user does not have to worry about the wear and tear of a track. In addition, the components for creating a swinging or swiveling carriage can be easier to care for and replace than the components for a rolling leg support on a track. 
     Although the invention has been described with reference to one or more preferred embodiments, the description is not to be construed in a limiting sense. There is modification of the disclosed embodiments, as well as alternative embodiments of this invention, which will be apparent to persons of ordinary skill in the art and various changes in form and detail may be made therein without departing from the spirit and scope of the invention. The invention shall be viewed as limited only by reference to the following claims.