Patent Publication Number: US-8986176-B2

Title: Isoped exercise device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. patent application Ser. No. 12/798,781, filed Apr. 12, 2010, which is hereby incorporated herein by reference in its entirety. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Exercise is consistent with physical and mental health. Exercise of the lower extremities including the gluteous maximus, thighs, calves, hamstrings, and the like may be difficult for one with limited mobility, who is chair bound, or with a demanding schedule. A lack of exercise may result in not achieving proper circulation to lower extremities and/or other parts of the body. 
     SUMMARY 
     Some embodiments are directed to an exercise device. Other embodiments include unique systems and methods for utilizing the exercise device disclosed herein. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the below description and drawings. 
     In an embodiment, an exercise device comprises a base frame comprising a plurality of belt members attached to, and arranged in parallel on the base frame, wherein each of the belt members comprises: a front axle attached to the base frame oriented along a front central axis separated by a distance from a rear axle attached to the base frame having a rear central axis, wherein the front central axis is essentially parallel to the rear central axis; a front roller disposed around the front axle and arranged to rotate around the front central axis; a rear roller disposed around the rear axle and arranged to rotate around the rear central axis; an endless belt having an infinite number of sides disposed around and in contact with a portion of the front roller and a portion of the rear roller, the endless belt having a major axis oriented perpendicular to the front central axis and a minor axis oriented parallel to the front central axis; the exercise device further comprising at least one frictional member disposed in frictional contact with, and forcibly biased against a surface of at least one front roller, rear roller, or a combination thereof such that an external force directed perpendicular to the front central axis applied to at least one of the endless belts is opposed by a frictional force provided by the frictional contact between the frictional member and the at least one surface of the front roller, the rear roller, or a combination thereof. 
     In an embodiment, a method to exercise comprises applying an external force to an endless belt of an exercise device in an amount sufficient to overcome a frictional force provided by the exercise device opposed to the applied force, wherein the exercise device comprises a base frame comprising a plurality of belt members attached to, and arranged in parallel on the base frame, wherein each of the belt members comprises: a front axle attached to the base frame oriented along a front central axis separated by a distance from a rear axle attached to the base frame having a rear central axis, wherein the front central axis is essentially parallel to the rear central axis; a front roller disposed around the front axle and arranged to rotate around the front central axis; a rear roller disposed around the rear axle and arranged to rotate around the rear central axis; the endless belt having an infinite number of sides disposed around and in contact with a portion of the front roller and a portion of the rear roller, the endless belt having a major axis oriented perpendicular to the front central axis and a minor axis oriented parallel to the front central axis; the exercise device further comprising at least one frictional member disposed in frictional contact with, and forcibly biased against a surface of at least one front roller, rear roller, or a combination thereof such that the external force directed perpendicular to the front central axis applied to at least one of the endless belts is opposed by the frictional force provided by the frictional contact between the frictional member and the at least one surface of the front roller, the rear roller, or a combination thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a front view of an exercise device according to an embodiment, of the instant disclosure; 
         FIG. 2A  is a cut-away side view along axis A-A of  FIG. 1  of an exercise device according to an embodiment, of the instant disclosure; 
         FIG. 2B  is a cut-away side view along axis B-B of  FIG. 1  of an exercise device according to an embodiment, of the instant disclosure; 
         FIG. 2C  is a partial cut-away side view along axis C-C of  FIG. 2B  of an exercise device according to an embodiment, of the instant disclosure; 
         FIG. 3A  is a schematic top view of an exercise device according to an embodiment, of the instant disclosure; 
         FIG. 3B  is a top view of an exercise device according to an embodiment, of the instant disclosure; 
         FIG. 4  is a partial cutaway side view of an exercise device according to an embodiment of the instant disclosure disposed on a horizontal surface. 
     
    
    
     DETAILED DESCRIPTION 
     At the outset, it should be noted that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. In addition, the composition used/disclosed herein can also comprise some components other than those cited. In the summary and this detailed description, each numerical value should be read once as modified by the term “about” (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary and this detailed description, it should be understood that a physical range listed or described as being useful, suitable, or the like, is intended that any and every value within the range, including the end points, is to be considered as having been stated. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors possessed knowledge of the entire range and all points within the range. 
     As used in the specification and claims, “near” is inclusive of “at.” 
     As used in the specification and claims, “forcibly biased” includes one material or surface being forced against another material or surface. 
     As used herein, a “major axis” of an item is longer than a “minor axis” of the same item. 
     As used herein, a “belt tension” includes a pulling force exerted by the belt when the belt is stretched between two points separated by a distance. 
     As shown in  FIG. 3A , in an embodiment, an exercise device  10  comprises a base frame  12  comprising a plurality of belt members, represented generally as  14  attached to, and arranged in parallel on base frame  12 . In an embodiment, each of belt members  14  comprises a front axle  16  attached to base frame  12  oriented along a front central axis  18  and separated by a distance  20  from a rear axle  22  attached to base frame  12  having a rear central axis  24 . In an embodiment, front central axis  18  is essentially parallel to rear central axis  24 . 
     In an embodiment, belt member  14  may further comprise a front roller disposed around front axle  16  and arranged to rotate around front central axis  18 . Belt member  14  may further comprise a rear roller  28  disposed around rear axle  22  and arranged to rotate around rear central axis  24 . As shown in  FIGS. 2A and 2B , in an embodiment, belt member  14  may further include an endless belt  30  having an infinite number of sides disposed around and in contact with a portion of front roller  26  and a portion of rear roller  28 . As shown in  FIG. 3B , in an embodiment, endless belt  30  may have a major axis  32  oriented perpendicular to front central axis  18  and a minor axis  34  oriented parallel to front central axis  18 . 
     In an embodiment, exercise device  10  further comprises at least one frictional member  36  disposed in frictional contact with, and forcibly biased against a surface, generally represented as  38 , of at least one front roller  26 , rear roller  28 , or a combination thereof, such that an external force  40  directed perpendicular to front central axis  18  applied to at least one of the endless belts  30  is opposed by a frictional force  42  provided by frictional contact between frictional member  36  and at least one surface  38  of front roller  26 , rear roller  28 , or a combination thereof. 
     In an embodiment, exercise device  10  comprises a frictional member  36  comprising a first end  44  attached to base frame  12 , and a second end  46  movably engaged with first end  44 , and a resilient member  48  disposed between, and in mechanical contact with first end  44  and second end  46 . In an embodiment, second end  46  further comprises a follower  50  arranged in frictional contact with surface  38  of front roller  26  and/or rear roller  28 , or a combination thereof (not shown), wherein resilient member  48  is dimensioned and arranged between first end  44  and second end  46  such that follower  50  is forcibly biased against surface  38  (generally represented by force arrow  52 ) of front roller  26  and/or rear roller, or a combination thereof (not shown), to provide fictional force  42  (see  FIG. 3B ). 
     Frictional force  42  may also be described as a drag force, a resistance to rotation of front roller  26  and/or rear roller  28  in response to an externally supplied force  40 , and/or the like. In an embodiment, frictional force  42  is diametrically opposed to, and a response to an applied external force  40 . 
     In an embodiment, resilient member  48  may comprise a compressible helical spring, an air compression cylinder and piston arrangement (not shown), and/or the like, so long as resilient member is capable of providing a force  52  to follower  50  such that follower  50  is forcibly biased against any external surface, indicated generally as  38 , of front roller  26 , rear roller  28 , or a combination thereof. 
     In an embodiment, frictional member  36  may further comprise an adjustment means  54  capable of providing a variable distance  56  between an end of resilient member  48  and first end  44  and/or first end  44  and base frame  12  (not shown), and/or increasing or reducing the compressive force of resilient member  48  such that the amount of bias force  52  exerted between frictional member  36  and surface  38  of at least one of front roller  26 , rear roller  28 , or a combination thereof is variable between an upper limit and a lower non-zero limit. In an embodiment, bias force  52 , and by extension frictional force  42  is greater than zero, such that at least one of the rollers is not free to rotate in the absence of an applied force, but is instead resistant to rotation around its corresponding axis and may only rotate upon application of an external force greater than the bias force applied by the frictional member. Accordingly, in an embodiment, the belt tension, internal or inherent friction of the various bearings, bushings and the like of the rollers, and/or the like are not factored into the representative bias force. 
     In an embodiment, follower  50  comprises a rotatable member  58  disposed around and in rotational contact with a follower axel  60  attached to second end  46 . In an embodiment, follower axle  60  is arranged such that rotatable member  58  has an axis of rotation  62  parallel to front central axis  18 . 
     In an embodiment, front axle  16 , rear axle  22 , or both are movably attachable  64  to base frame  12 . In an embodiment, front axle  16 , rear axle  22  are attachable  64  to base frame  12  in an arrangement to provide a belt tension, which is a tensile force represented generally by arrow  66  (see  FIG. 2A ) between front axle  16  and rear axle  22  through endless belt  30 . In an embodiment, belt tension  66 , a tensile force, is independent of the frictional force  42  and/or bias force  52  provided by the frictional contact between frictional member  36  and the at least one surface  38  of front roller  26  and/or rear roller  28 . Accordingly, in an embodiment, frictional member  36  does not force the front roller to move relative to the rear roller, and/or rear roller to move relative to front roller, but instead provides a frictional force which acts on the rollers to resist rotation of the roller about the axle on which the roller is mounted. 
     As shown in  FIG. 2C , in an embodiment, front roller  26 , rear roller  28 , or both comprise a radial groove  68  disposed into the surface of the roller which is dimensioned and arranged to receive a least a portion of frictional member  36 , which may include follower  50  (See  FIG. 3A ). 
     In an embodiment, frictional member  36  is forcibly biased against surface  38  of front roller  26  and/or rear roller  28  in a direction perpendicular to front central axis  18 . In an embodiment, frictional member  36  is forcibly biased against surface  38  of front roller  26  and/or rear roller  28  in a direction parallel to front central axis  18  (not shown). 
     As shown in  FIG. 3B , in an embodiment, exercise device  10  has two belt members  30 , wherein front central axis  18  of each of the two belt members and rear central axis  24  of each of the two belt members are collinear. 
     In an embodiment, at least one frictional member is frictionally engaged with two or more front rollers, two or more rear rollers, or any combination thereof (not shown). 
     In an embodiment, endless belts  30  of each of the belt members are independently movable in a direction perpendicular to front central axis  18  in a forward direction  70  from rear central axis  24  toward front central axis  18 , in a reverse direction  72  from front central axis  18  toward rear central axis  24 , or a combination thereof. 
     In an embodiment, base frame  12  is disposed within an outer covering  74 . In an embodiment, outer covering  74  comprising a plurality of openings  76  through which at least a portion of each of endless belts  30  protrudes. 
     As shown in  FIG. 4 , in an embodiment, base frame  12  is supported on a horizontal surface  78  by a plurality of supports  80  connected to the base frame, wherein supports  80  are dimensioned and arranged such that a line  82  connecting front central axis  18  and rear central axis  24  is oriented at an angle  84  of less than or equal to about 60°, or less than or equal to about 50°, or less than or equal to about 40°, or less than or equal to about 30°, or less than or equal to about 20°, or less than or equal to about 10° relative to horizontal surface  78 . 
     In an embodiment, at least one of the plurality of supports  80  is independently adjustable  86  such that the angle  84  between line  82  connecting front central axis  18  and rear central axis  24  and horizontal surface  78  is adjustable between about 0° and about 60° relative to horizontal surface  78 . 
     In an embodiment, frictional force  42  opposed to applied external force  40  directed perpendicular to front central axis  18  applied to at least one of the endless belts  30  is from about 1% to less than or equal to about 90%, or less than or equal to about 80%, or less than or equal to about 70%, or less than or equal to about 60%, or less than or equal to about 50%, or less than or equal to about 40%, or less than or equal to about 30%, or less than or equal to about 20%, or less than or equal to about 10% of applied external force  40 . In an embodiment, frictional force  42  may be from about 0.44 N (0.1 pound force) to about 44.5 N (10 pound force). 
     In an embodiment, distance  20  is greater than or equal to about 10 cm and less than or equal to about 50 cm and/or the minor axis  34  of endless belt  30  is from about 5% to about 90% of distance  20 . 
     In an embodiment, endless belt  30  comprises a plurality of ribs  88  disposed on one or more sides of endless belt  30 . In an embodiment, the plurality of ribs  88  are oriented perpendicular to or at an acute angle relative to major axis  32  of endless belt  30 . 
     In an embodiment, a method to exercise comprises applying an external force to an endless belt of an embodiment of an exercise device as described herein in an amount sufficient to overcome the frictional force provided by the exercise device opposed to the applied force. In an embodiment, a method to exercise comprises applying an external force to an endless belt of an embodiment of an exercise device as described herein in an amount sufficient to overcome the frictional force provided by the exercise device opposed to the applied force, wherein the external force is applied by a user&#39;s foot and/or leg, wherein the user is a person in a sitting position. 
     In an embodiment, the exercise device according to an embodiment may provide the user with a passive resistance to normal motion of the back of the thigh muscles, the lower legs (calves) and ankles while sitting. Since the motion may be in a periodic or a reciprocating action, similar to walking, little or no motion would be transmitted from the user to the chair or other sitting device. However, this exercise device disclosed herein may be utilized in a standing position depending on the physical limitations of the user. 
     In an embodiment, internal part count and weight may be minimized and the components designed to minimize the use of friction in all moving parts. In an embodiment, the exercise device may be designed to require zero maintenance for a period of at least three years. 
     In an embodiment, the base frame assembly may serve as the primary structure wherein all vertical and horizontal loads are reacted by, and transferred through, the base member into the surface on which the device is disposed. The exercise device according to the instant disclosure may be designed to allow easy assembly of all working components during manufacturing as well as during shop servicing. In an embodiment, material selection for the various components including the material to be used in the fabrication of the base frame may include steel, glass fiber reinforced bulk molding compound (bmc), fiberglass, and/or the like. In an embodiment, a recyclable base polymer may be specified. In an embodiment, the base frame material may be chosen such that the base frame is able to withstand a minimum of 15 drops from a height of 36 inches (as part of the finished product) without cracking or damage to any of the internal parts. 
     In an embodiment, the base frame may be designed to support a maximum static (non-operating) load of at least about 250 pounds evenly distributed over each of the belts. Loads passed through the base frame will be reacted by the floor or a structurally sound platform supplied by the end user. Material thickness and sections may be determined by allowable deflections based on anticipated external, as well as internal, loading according to methods well understood by one of minimal skill in the art. In an embodiment, the outer covering comprises two separate pieces, which may be dimensioned and arranged to snap together using an integral snap device  90  as shown in  FIG. 2B . In an embodiment, mechanical fasteners may be used to hold the two or more separate pieces together. 
     The outer cover serves to protect all internal components from liquid spills and damage from falling objects. As depicted in  FIG. 1 , all features are generously radiused to prevent injury during handling or transport. The parting line between the base member and the outer cover may be held to a profile tolerance sufficient to minimize gaps. The material which may be used in the fabrication of the outer cover may be the same or different as the material used to produce the base frame. 
     In and embodiment, the outer cover may be dimensioned to withstand overhead drops of a 1 pound steel object at a height of 12 inches one time at any location without cracking through. 
     The endless belts may further comprise a surface modifier comprising a low friction layer such as perfluoroethylene to minimize wear. In an embodiment, the endless belts may comprise and elastomeric base material, which may include ethylene propylene diene monomer (epdm) rubber, butyl rubber, and/or the like, which may be further reinforced with carbon fiber, metal cords, polyester cords, and/or the like. 
     Lateral ribs disposed on a surface of the belt may be molded to provide comfortable contact with bare feet and may be dimensioned to facilitate bending around the two rollers without cracking. 
     As shown in  FIG. 2C , in an embodiment, the front and/or rear rollers  26  or  28  may comprise a roller assembly  102  comprising two ball bearings  94 , two bearing retainers  98 , an inner core  96 , and an outer shell  100 . The “v” notch or radial groove disposed into the roller may be dimensioned and arranged to provide guidance of each belt engagement which may be over 180° of arc, and to activate the separating load via rolling contact on center with the rotatable member of the follower. 
     In an embodiment, the rollers, and/or any surface of the device may comprise a wear resistant surface treatment  92  which may include a coating of titanium-nitride or the like for wear resistance. In an embodiment, the bearings  94  utilized in the design may be self-lubricated, steel, plastic, and/or ceramic ball type bearings and/or bushings which may be sealed to reduce likelihood of contamination. In an embodiment, the frictional member may comprise metal, and/or a polymeric resin, which may include glass or other fiber reinforced polyetheretherketone (peek), nylon, ABS, and/or the like. In an embodiment, the front axil, the rear axil, or both may an alloy steel, may be heat treated, or a combination thereof. 
     In an embodiment, the resilient member comprises a helical spring. The adjustment means may include a threated member and corresponding seat adapted to receive the threaded member such that rotation of the threaded member increases or decreases the amount of compression of the spring, thereby providing an adjustment of the frictional force provided by the exercise device in response to an applied force. In an embodiment, the adjustment means is accessible from the outer surface of the exercise device such that the frictional force may be adjusted by the end user. In an embodiment, the frictional member may be oriented to produce the bias force parallel to the front central axis such that the frictional force is applied to an end of the roller. In an embodiment, the resilient member may comprise a gas charged cylinder-piston arrangement capable of producing a consistent outward force. In an embodiment, the pressure in the gas charged cylinder-piston arrangement may be adjustable or variable to allow for adjustment of the frictional force. In an embodiment, the frictional force may be provide by a plurality of frictionally engaged dampers which rotate with a roller relative to a stationary platform which exerts a force on the dampers, with or without a resilient member, to provide the frictional force. 
     Accordingly, the present invention provides the following embodiments of the invention: 
     A. An Exercise Device Comprising: 
     a base frame comprising a plurality of belt members attached to, and arranged in parallel on the base frame, wherein each of the belt members comprises: 
     a front axle attached to the base frame oriented along a front central axis separated by a distance from a rear axle attached to the base frame having a rear central axis, wherein the front central axis is essentially parallel to the rear central axis; 
     a front roller disposed around the front axle and arranged to rotate around the front central axis; 
     a rear roller disposed around the rear axle and arranged to rotate around the rear central axis; 
     an endless belt having an infinite number of sides disposed around and in contact with a portion of the front roller and a portion of the rear roller, the endless belt having a major axis oriented perpendicular to the front central axis and a minor axis oriented parallel to the front central axis; 
     the exercise device further comprising at least one frictional member disposed in frictional contact with, and forcibly biased against a surface of at least one front roller, rear roller, or a combination thereof such that an external force directed perpendicular to the front central axis applied to at least one of the endless belts is opposed by a frictional force provided by the frictional contact between the frictional member and the at least one surface of the front roller, the rear roller, or a combination thereof. 
     B. The exercise device according to embodiment A, wherein the frictional member comprises a first end attached to the base frame, and a second end movably engaged with the first end, and a resilient member disposed between, and in mechanical contact with the first end and the second end, 
     wherein the second end further comprises a follower arranged in frictional contact with the surface of the front roller, the rear roller, or a combination thereof, wherein the resilient member is dimensioned and arranged between the first end and the second end such that the follower is forcibly biased against the surface of the front roller, the rear roller, or a combination thereof, to provide the fictional force. 
     C. The exercise device according to embodiment A or B, wherein the resilient member comprises a compressible helical spring. 
     D. The exercise device according to embodiment A, B, or C, wherein the frictional member further comprises an adjustment means capable of providing a variable distance between the resilient member and the first end, the first end and the base frame, or a combination thereof such that the amount of bias force between the frictional member and the surface of at least one of the front roller, the rear roller, or a combination thereof is variable between an upper limit and a lower non-zero limit. 
     E. The exercise device according to embodiment A, B, C, or D, wherein the follower comprises a rotatable member disposed around and in rotational contact with a follower axel attached to the second end, wherein the follower axle is arranged such that the rotatable member has an axis of rotation parallel to the front central axis. 
     F. The exercise device according to embodiment A, B, C, D, or E, wherein the front axle, the rear axle, or both are movably attachable to the base frame, and are attachable to the base frame in an arrangement to provide a belt tension between the front axle and the rear axle through the endless belt, wherein the belt tension is independent of the frictional force provided by the frictional contact between the frictional member and the at least one surface of the front roller, the rear roller, or a combination thereof. 
     G. The exercise device according to embodiment A, B, C, D, E, or F, wherein the front roller, the rear roller, or both comprise a radial groove disposed into the surface of the roller which is dimensioned and arranged to receive a least a portion of the follower. 
     H. The exercise device according to embodiment A, B, C, D, E, F, or G, wherein the frictional member is forcibly biased against the surface of the front roller, the rear roller, or both in a direction perpendicular to the front central axis. 
     I. The exercise device according to embodiment A, B, C, D, E, F, G, or H having two belt members, wherein the front central axis and the rear central axis of each of the belt members are collinear. 
     J. The exercise device according to embodiment A, B, C, D, E, F, G, H, or I, comprising at least one frictional member which is frictionally engaged with two or more of the front rollers, two or more of the rear rollers, or any combination thereof. 
     K. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, or J, wherein each of the endless belts are independently movable in a direction perpendicular to the front central axis in a direction from the rear central axis toward the front central axis, in a direction from the front central axis toward the rear central axis, or a combination thereof. 
     L. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, J, or K, wherein the base frame is disposed within an outer covering, the outer covering comprising a plurality of openings through which at least a portion of each of the endless belts protrudes through. 
     M. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, J, K, or L, wherein the base frame is supported on a horizontal surface by a plurality of supports connected to the base frame, and wherein the supports are dimensioned and arranged such that a line connecting the front central axis and the rear central axis is oriented at an angle of less than or equal to about 60° relative to the horizontal surface. 
     N. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, J, K, L, or M, wherein at least one of the plurality of supports is independently adjustable such that the angle between the line connecting the front central axis and the rear central axis and the horizontal surface is adjustable between about 0° and about 60° relative to the horizontal surface. 
     O. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, or N, wherein the frictional force opposed to the applied external force directed perpendicular to the front central axis applied to at least one of the endless belts is from about 1% to less than or equal to about 90% of the applied external force. 
     P. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, N, or O, wherein the distance is greater than or equal to about 10 cm and less than or equal to about 50 cm, and wherein the minor axis of the endless belt is from about 5% to about 90% of the distance. 
     Q. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, or P, wherein the endless belt comprises a plurality of ribs disposed on one or more sides of the endless belt. 
     R. The exercise device according to embodiment A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, or Q, wherein the plurality of ribs are oriented perpendicular to the major axis of the endless belt. 
     S. A method to exercise comprising applying an external force to an endless belt of an exercise device in an amount sufficient to overcome a frictional force provided by the exercise device opposed to the applied force, wherein the exercise device comprises any one of the embodiments of A-R. 
     T. A method to exercise comprising applying an external force to an endless belt of an exercise device in an amount sufficient to overcome a frictional force provided by the exercise device opposed to the applied force, wherein the exercise device comprises a base frame comprising a plurality of belt members attached to, and arranged in parallel on the base frame, wherein each of the belt members comprises: 
     a front axle attached to the base frame oriented along a front central axis separated by a distance from a rear axle attached to the base frame having a rear central axis, wherein the front central axis is essentially parallel to the rear central axis; 
     a front roller disposed around the front axle and arranged to rotate around the front central axis; 
     a rear roller disposed around the rear axle and arranged to rotate around the rear central axis; 
     the endless belt having an infinite number of sides disposed around and in contact with a portion of the front roller and a portion of the rear roller, the endless belt having a major axis oriented perpendicular to the front central axis and a minor axis oriented parallel to the front central axis; 
     the exercise device further comprising at least one frictional member disposed in frictional contact with, and forcibly biased against a surface of at least one front roller, rear roller, or a combination thereof such that the external force directed perpendicular to the front central axis applied to at least one of the endless belts is opposed by the frictional force provided by the frictional contact between the frictional member and the at least one surface of the front roller, the rear roller, or a combination thereof. 
     The foregoing disclosure and description of the invention is illustrative and explanatory thereof and it can be readily appreciated by those skilled in the art that various changes in the size, shape and materials, as well as in the details of the illustrated construction or combinations of the elements described herein can be made without departing from the spirit of the invention. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only some embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred, more preferred or exemplary utilized in the description above indicate that the feature so described may be more desirable or characteristic, nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.