Abstract:
An exercise device for performing a variety of movement patterns. The exercise device has a pair of linkages, each including an upper link pivotally mounted to a frame and a lower link pivotally coupled to an upper link. A foot support is provided on a distal end of each lower link. A transfer system is coupled to the frame and both upper links for transferring both tensile and compressive forces. Separate torque elements are operably coupled to the frame and each lower link via a transfer member for independently resisting movement of the associated lower link.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to exercise equipment and more particularly, to exercise equipment which simulate or facilitate ambulatory human movement. 
       BACKGROUND OF THE INVENTION 
       [0002]    Exercise is a necessary part of a healthy lifestyle. Without proper exercise, muscle tissue decreases, the mineral density of bones decline and people tend toward storing more fat weight. This contributes to a variety of health issues including cardiovascular disease, osteoporosis and diabetes. A common aerobic exercise is running. The ground pounding action of running can cause joint issues in some people. In addition, running outdoors requires a suitable space and environment. Weather and personal safety restrict some individuals from performing this activity as often as they would like, as running in bad weather or a bad neighborhood can result in more serious problems than heart disease. 
         [0003]    Indoor running and walking can be accomplished by use of a treadmill, but again, the pounding action of the foot on the tread may lead to joint overuse injuries. Other products such as elliptical trainers address this problem but restrict the user to a set gait pattern. Any slight variation between the user&#39;s natural gait and the machine&#39;s predetermined gait may cause an imbalance in joint loading, as well as muscular development of the limbs being used. Given that people have different stride lengths and they vary greatly in height and weight, it is unlikely that a single predefined gait would be ideal for all users. 
         [0004]    It should, therefore, be appreciated that there is a need for a fitness device that enables movement in a variety of gait patterns with minimal transition effort from one pattern to another. The present invention fulfills this need and others. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides a frame that supports a first upper leg link and a second upper leg link, each pivotally coupled to the frame. A first lower leg link may be pivotally coupled to the first upper leg link and a second lower leg link may be pivotally coupled to the second upper leg link, each lower leg link may include a foot support. A first transfer system may be provided which may be movably coupled to the frame and include a first transfer member coupled to the first upper leg link and a second transfer member coupled to the second upper leg link. A second transfer system may be provided which is movably coupled to the frame, and may include a pair of third transfer members, coupled to each of a pair of fourth transfer members by way of each of a pair of transfer couplings, each of which may be movably mounted to the frame. The fourth transfer members may be coupled to the first lower leg link and the second lower leg link, whereby movement of the first lower leg link may cause movement of the second lower leg link irrespective of movement of the upper leg links. 
         [0006]    In one embodiment of the invention, the first transfer system may be comprised of a first gear and a second gear, whereby rotation of the first gear results in rotation in an opposite direction of the second gear. The first transfer system may also be comprised of a pivot bar with a first end and a second end and pivotally mounted to the frame. The first end may be coupled to the first transfer member and the second end may be coupled to the second transfer member. 
         [0007]    The exercise device may also include a support system, defining a lowest position of the foot supports. The support system may be comprised of a compression link with a first end coupled to the frame and a second end coupled to a lower leg link. The compression link may be comprised of a housing, a rod received by the housing and a bias member captured between the housing and the rod, thereby limiting the amount of displacement of the rod relative to the housing. The support system may include a first compression link coupled to the first lower leg link and a second compression link coupled to the second lower leg link. 
         [0008]    The support system may be comprised of one or more belts, each movably coupled to the frame by at least two pulleys. The belt may include an upper run positioned adjacent to a lower portion of the foot support and adapted for contact with the upper run, thereby the belt may limit the vertical displacement of the foot support. The support system may be comprised of a belt take-up coupled to the frame, the belt take-up may be biased to provide tension in the belt. The support system may also include a belt drive, such as a motor or other power device, operationally coupled to the belt to enable continuous rotation of one or more of the pulleys, thereby allowing continuous movement of the belt in the absence of power input from a user. 
         [0009]    For purposes of summarizing the invention and the advantages achieved over the prior art, certain advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such advantages can be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention can be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
         [0010]    All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following description of the preferred embodiments and drawings, the invention not being limited to any particular embodiment(s) disclosed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings, in which: 
           [0012]      FIG. 1  is an isometric view of an exercise device incorporating a system enabling varied gait movements in accordance with the present invention. 
           [0013]      FIG. 2  is an isometric partial detail of a transfer system with a portion of the frame removed for visual clarity, the view shown along line  2 - 2  in  FIG. 1 . 
           [0014]      FIG. 3  is an isometric view of a linkage system of the exercise device shown in  FIG. 1  with the frame removed. 
           [0015]      FIG. 4  is an isometric view of a detail of an upper leg link pivot of the linkage shown in  FIG. 3 , the detail shown in  FIG. 3  along line  4 - 4 . 
           [0016]      FIG. 5  is an isometric view of the linkage of  FIG. 3  shown from the front, left. 
           [0017]      FIG. 6  is an isometric view of a detail of the upper leg link pivot of the linkage shown in  FIG. 5 , the detail shown in  FIG. 5  along line  6 - 6 . 
           [0018]      FIG. 7  is a side view of the exercise device of  FIG. 1  with dashed lines illustrating different walking and running pedal paths. 
           [0019]      FIG. 8  is a side view of the exercise device of  FIG. 1  with dashed lines illustrating an inclined step pedal path. 
           [0020]      FIG. 9  is an isometric view of an exercise device incorporating a system enabling varied gait movements, the device including a transfer system comprising a pivot bar. 
           [0021]      FIG. 10  is a rear isometric view of the device of  FIG. 9  with a cover removed to show a transfer system. 
           [0022]      FIG. 11  is a detail of the device of  FIG. 10  shown along line  11 - 11 , illustrating a transfer system in more detail. 
           [0023]      FIG. 12  is a detail of the device of  FIG. 10  Shown along line  12 - 12 , illustrating an upper link pivot area in more detail. 
           [0024]      FIG. 13  is an isometric view of an exercise device incorporating a system enabling varied gait movements and including a support system including a compression link. 
           [0025]      FIG. 14  is a detail of the device of  FIG. 13  shown along line  14 - 14 , illustrating a compression link with the cover partially removed. 
           [0026]      FIG. 15  is a side view of the device of  FIG. 13  showing different pedal paths as may be guided by a compression link positioned in different positions relative to the frame, and the pedals in a relatively vertical orientation. 
           [0027]      FIG. 16  is a detail of the device of  FIG. 15  shown along line  16 - 16 , illustrating a compression link with the cover partially removed. 
           [0028]      FIG. 17  is a side view of the device of  FIG. 15  showing different pedal paths as may be guided by a compression link positioned in different positions relative to the frame, and the pedals in a relatively horizontal position. 
           [0029]      FIG. 18  is a detail of the device of  FIG. 17  shown along line  18 - 18 , illustrating a compression link with a cover partially removed. 
           [0030]      FIG. 19  is a side view of an exercise device incorporating a system enabling varied gait movements and including a support system comprising a belt. 
           [0031]      FIG. 20  is an isometric view of the device of  FIG. 19  from a front, side orientation. 
           [0032]      FIG. 21  is a detail of the device of  FIG. 20  shown along line  21 - 21 , illustrating front pulleys of a support system. 
           [0033]      FIG. 22  is a detail of the device of  FIG. 20  shown along line  22 - 22 , illustrating rear pulleys of a support system. 
           [0034]      FIG. 23  is a rear isometric view of an exercise device incorporating a system enabling varied gait movements in accordance with the present invention. 
           [0035]      FIG. 24  is a detail of the device of  FIG. 23  shown along line  24 - 24 , showing a rear view of drive elements of the device. 
           [0036]      FIG. 25  is a front view of the drive elements of the device of  FIG. 23 . 
           [0037]      FIG. 26  is a side view of an exercise device incorporating a system enabling varied gait movements and providing an articulating leg. 
           [0038]      FIG. 27  is an isometric view of the device of  FIG. 26 . 
           [0039]      FIG. 28  is a detail of the device of  FIG. 27  shown along line  28 - 28 , showing a side isometric view of support system elements of the device. 
           [0040]      FIG. 29  is a right front isometric view of the device of  FIG. 27 . 
           [0041]      FIG. 30  is a detail of the device of  FIG. 29  shown along line  30 - 30 , showing a side isometric view of a front portion of a support system of the device. 
           [0042]      FIG. 31  is a detail of the device of  FIG. 29  shown along line  31 - 31 , showing a side isometric view of a resistance system of the device. 
           [0043]      FIG. 32  is a side view of an exercise device incorporating a system enabling varied gait movements, the device including a transfer system comprising a pivot bar and a support system. 
           [0044]      FIG. 33  is an isometric view of the device of  FIG. 32  with a bottom cover and a portion of the frame removed. 
           [0045]      FIG. 34  is a detail of the device of  FIG. 33  shown along line  34 - 34 , showing an isometric view of a transfer system. 
           [0046]      FIG. 35  is a detail of the device of  FIG. 33  shown along line  35 - 35 , showing an isometric view of an upper link and support system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0047]    With reference to the illustrative drawings, and particularly to  FIGS. 1-6 , there is shown an exercise device in the form of a multifunctional adaptive training device  38 . This embodiment of the invention may include a frame  36  supporting a pair of leg linkages including a first leg linkage  40  and a second leg linkage  42 . The first leg linkage  40  may include a first upper link  44  coupled to a first lower link  46 . In a like manner, a second leg linkage  42  may include a second upper link  48  coupled to a second lower link  50 . A foot support  52  may be positioned on a distal end of each of the first lower link  46  and the second lower link  50 . A user may position themselves with one foot on each of the foot supports  52  and perform a variety of different exercises. 
         [0048]    The foot supports  52  are linked from one to the other by way of a first transfer system  54  and a second transfer system  56 . The first transfer system  54  may include a first transfer member  58 , coupled to the first upper link  44  and a second transfer member  60  coupled to the second upper link  48 . The first transfer system  54  may also include a first transfer bar  62  enabling substantially opposing motion of the first transfer member  58  relative to the second transfer member  60 . The substantially opposing motion may be achieved through a first gear  64  mounted adjacent to a second gear  66  and the first transfer member  58  being coupled to the first gear  64  and the second transfer member  60  being coupled to the second gear  66  by way of the first transfer bar  62 . This combination may provide a substantially reciprocating motion of the first upper link  44  relative to the second upper link  48 . 
         [0049]    To complete the linking of the foot supports  52  of the first leg linkage  40  to that of the second leg linkage  42 , the first lower link  46  may be linked to the second lower link  50 . This may be done by coupling a pair of third transfer members  68 , one each to the first lower link  46  and one to the second lower link  50 . A pair of transfer couplings  70  may be supported on the frame  36  and coupling each of the pair of third transfer members  68  to each of a pair of fourth transfer members  72 . The fourth transfer members  72  are coupled one to the other by way of the second transfer system  56 , thereby enabling substantially reciprocating motion of the fourth transfer members, one to the other. A second transfer bar  74  may be used to transmit torque from one of the fourth transfer members  72  to the other. 
         [0050]    As with the first transfer system  54 , the second transfer system  56  may include a third gear  76  coupled to the second transfer bar  74  and a fourth gear  78 , adjacent to the third gear  76 . The fourth gear  78  may be coupled to one of the fourth transfer members  72  and the second transfer bar  74  coupled to the other fourth transfer member  72 , thereby enabling substantially reciprocating motion of the fourth transfer members  72 , relative to the other. This action could provide substantially opposite movement of the third transfer members  68  one to the other, which may provide substantially opposite movement of the first lower link  46  relative to the second lower link  50 . With both the first transfer system  54  and the second transfer system  56  the movement of one foot support  52  to the other may be controlled. Each foot support  52  may be placed in an infinite number of positions within its plane of movement. In doing so, the other foot support  52  will be placed in a specific position in space within its plane of movement. This combination enables a path of motion of a foot support  52  that is not confined by the machine as it is infinitely variable by the user. The stability to the user is provided by the linked positioning of each foot support  52 , thereby providing a stable platform to support the user. 
         [0051]    With reference to  FIGS. 2, 3 and 5 , a means of offering resistance is provided. When a person runs or walks on a flat surface with no wind, there is no resistance to motion. The runner&#39;s potential energy is the same at the end of the run as it was at the beginning of the running workout. Energy has been expended through the mechanics of the running or walking gait. The center of mass of the user is lifted and dropped in each stride. In addition, the mass of the leg segments have been accelerated to provide a complex motion that is repeated with every stride. This is work done by the runner where no energy has been stored, but it has been expended by the runner. These aspects of energy expenditure may also be apparent with the invention disclosed herein. The running gait of the legs may be identical to that of a runner on a flat or graded surface and therefore the energy required by the user to manipulate and change direction of the legs is provided by the user. This may be exaggerated by the mass of the first leg linkage  40  and the second leg linkage  42  that are added to the mass of the runner&#39;s legs. The vertical displacement of the center of mass of the user may also be provided with the present invention. 
         [0052]    In some cases it may be desired to add additional resistance to the movement of the first transfer system  54 , the second transfer system  56 , or both. This may be accomplished by a brake  80  or other resistance element to either transfer system ( 54  &amp;  56 ). In  FIGS. 2, 3 and 5  a brake  80  is added to resist the rotation of the first transfer bar  62  of the first transfer system  54  and a second brake  80  is provided to resist rotation of the second transfer bar  74  of the second transfer system  56 . One or both brakes  80  may be used to add torque to their respective transfer system ( 54  &amp;  56 ) to increase the workload as if a runner was training by running in soft sand. In addition, by adding resistance to one or the other transfer system ( 54  &amp;  56 ) the running gait may be modified for the user. This may be desired if a deficiency is identified and specific training is needed to correct that deficiency. 
         [0053]    Another use of the brakes  80  is to add support to the foot supports  52  during ingress and egress of the user with the machine. By engaging both brakes  80 , the foot supports 52  may be effectively locked in position and then slowly released to provide a method of smooth and stable entering and exiting of the exercise device  38 . By reducing any rapid movements during the ingress and egress, the user is much less likely to feel unstable, thereby possibly reducing the likelihood of feeling unstable. 
         [0054]    In that the system as described provides a stable platform for the user by placing one foot support  52  is a specific position in space, as determined by the other foot support  52 , it may be desirable to alter this relationship between the foot supports  52 . One method of accomplishing this is to alter the length of the third transfer members  68 . As depicted in  FIGS. 1, 3 and 5 , the third transfer members  68  may include an actuator  82  with a bearing mount  84  on each end thereof. The actuator  82  enables the distance between the bearing mounts  84  to be changed, thereby altering the angle between the first upper link  44  and the first lower link  46  and likewise between the second upper link  48  and the second lower link  50 . By altering these angles, the position of the foot supports  52  is changed relative to the frame  36  and therefore relative to one another, thereby altering the gait patterns. 
         [0055]    Some examples of the variations in gait patterns that may be obtained, without altering the length of the third transfer members  68 , are shown in  FIGS. 7 and 8 . In  FIG. 7  the longer path  86  is consistent with a desired foot path of travel for a running gait. For a walking gait, a shorter path  88  is shown. The invention  38  automatically relates the amplitude (vertical height) of the travel of the foot support  52  to the longitude (stride length) as these also naturally correlate in typical gait patterns in people. Therefore in many cases the invention  38  may not need to be altered to have the user transition from one gait pattern to another during use. This enables a smooth and fluid transition from one gait to another. If it is desired to alter the path, the third transfer member  68  may be changed during use without the user stopping the machine  38 . The arcuate path  90  depicts a pendulum path which may be used as a recovery gait. 
         [0056]    In  FIG. 8  a more extreme vertical path  92  of movement is shown. Again, this may be provided without altering the length of the third transfer member  68 . It shows a foot path that may be consistent with climbing stairs or a steep incline hill such as in hiking. The capability of the device  38  enables a great deal of versatility that is expressed only by a few of the infinite number of gait patterns possible by the device  38 . 
         [0057]    The gate patterns may be controlled to guide the user into a specific pattern by replacing the brakes  80  with drive motors, such as servo or stepper motors. One embodiment of this system is to make one transfer system a driver and the other transfer system driven. For illustrative purposes, a system will be described where the first transfer system  54  is the driver and the second transfer system  56  is driven. It is understood that the status of driver and driven may be reversed and the system as described may be substantially the same only reversed with regard to which is sensed and which is driven. With that in mind, using servo motors to replace each of the brakes  80 , provides a means of developing torque about the first transfer bar  62  and the second transfer bar  74 . In that servo motors have a shaft location device built in, there would not be a need for an external encoder or other device to sense the position, direction and speed of the motor shafts, and therefore the associated first transfer bar  62  and the second transfer bar  74 . If a stepper motor is used in place of servo motors to replace the brakes  80 , then a sensing device of at least the first transfer bar  62  would be used. 
         [0058]    In this embodiment, as a user drives a foot support  52  some direction at some speed, and the first upper link  44  and therefore also the second upper link  48  are displaced, the first transfer bar  62  will rotate some amount, in some direction, and at some speed. A sensor, such as the encoder in the servo motor, may be used to gather the information about the location, direction of movement and speed of movement of the motor and therefore the first transfer bar  62 . This information may be used to determine the gait pattern, as this information may be specific to a particular gait pattern, or a specific gait pattern may be pre-selected by the user. An algorithm may be provided to correlate the location and direction of movement of the first transfer bar  62  (driver) to a desired position of the second transfer bar  74  (driven) for that gait pattern. The motor (formally the brake  80 ) associated with the second transfer bar  74  may be actuated to drive the second transfer bar  74  to the position as determined by the information of the first transfer bar  62  as computed by the algorithm. This process electronically links the first transfer system  54  to the second transfer system  56  while still allowing the user to determine the path and speed of movement of the foot supports  52 , and therefore the feet of the user. By linking the first transfer system  54  to the second transfer system  56  a defined path of motion of the foot supports  52  may be provided. Through an electronic linking, how they are linked may be infinitely variable. With current processor technology a read and react closed loop system of 500-1000 Hz is possible, providing for a smooth path with little or no “cogging” of the movement making this a viable system with technology currently available. 
         [0059]    With reference to  FIGS. 9-12 , another embodiment of the current invention  38 ′ is shown. In this embodiment the invention  38 ′ has a first upper link  44 ′ a second upper link  48 ′, a first lower link  46 ′, a second lower link  50 ′ and a third transfer member  68 ′ connected to the first lower link  46 ′ and the second lower link  50 ′. The transfer coupling  70 ′ transfers load from the third transfer members  68 ′ to the fourth transfer members  72 ′ and a first transfer member  58 ′ is coupled to a second transfer member  60 ′ by way of a first transfer system  54 ′, comprising a pivoting arm  94 , thereby providing substantially reciprocating motion of the first transfer member  58 ′ to the second transfer member  60 ′. 
         [0060]    A second transfer system  56 ′ is provided to accomplish a similar reciprocating motion of the fourth transfer members  72 ′. In this embodiment the transfer coupling  70 ′ is substantially longitudinal providing a classic 1 st  class lever as opposed to the previously disclosed embodiment where the load and the force may be considered to be on the same side of the fulcrum (2 nd  or 3 rd  class lever). In this case the load in the fourth transfer members  72 ′ may always be in tension. As such, a pliable member such as a cord or cable may be used as opposed to a rigid structural element such as a steel bar. A second pivot arm  96  may provide the substantially reciprocating motion for the fourth transfer members  72 ′, that as with the pivoting arm  94 , the second pivoting arm  96  is a substantially rigid arm that is pivotally mounted to the frame, about a center point along the long axis, the ends free to move so as one end is lowered, the other end is raised relative to the frame  36 ′. This action enables the respective transfer members ( 72 ′ to  72 ′ and  58 ′ to  60 ′) to move in a substantially reciprocating manner relative to one another. In this embodiment a hydraulic damper  98  may be used to offer resistance to movement of one or both transfer systems ( 54 ′ and  56 ′). The damper  98  may be attached to the first transfer member  58 ′ and the second transfer member  60 ′ at or near the transfer couplings  70 ′ or at any other place in the system. 
         [0061]    An alternative embodiment of the invention including a support system  99  comprised of a compression link  100  is shown in  FIGS. 13-18 . The compression link  100  may be two compression links  100 , each with a shaft  102 , both shafts  102  with a first end coupled to each of the first lower link  46 , and the second lower link  50 . The shaft  102  of each compression link  100  may be received by a sleeve  104 , which may be coupled to a link mount  108 , which may be mounted to the frame  36 . A compression spring  106  may be received within the sleeve  104 . The spring  106  may act as a bias against extension of the shaft  102  out of the sleeve  104 . By doing so, the expanded distance of the compression link  100  is limited by the spring and the extension force on the shaft  102 . With one end of the compression link  100  coupled to the frame, by way of the link mount  108 , and the other end coupled to the lower links ( 46  &amp;  50 ) of the device  38 ″, the lowest position of the foot support  52  is restricted by the compression force of the spring  106  of the compression link  100 . In doing so, as a user passes through the stance phase of running, where the highest normal force is applied to a supporting surface, the greatest tension will be placed on the spring  106 . This may allow the greatest length of the compression link  100 . 
         [0062]    As is illustrated in  FIG. 15 , the small curve  110  is representative of the foot support  52  path of travel for a walking gait. It can be seen that at the bottom position of the foot support  52 , a smooth arcuate path may be provided. As the user begins to shift their weight onto the top foot support  52 , as the foot transitions forward during the “swing phase”, the forward foot will begin to drop as the trailing foot begins to raise as the users weight is transferred from the foot ending the stance phase (approaching “toe off” to transition to the swing phase) to the foot ending the swing phase (approaching “heel strike” to transition to the stance phase). As the user&#39;s body weight begins to be removed from the stance (bottom) foot, the spring  106  may bias the shaft  102  in toward the sleeve  104 , thereby shortening overall length of the compression link  100 . This will pull the lower link  46 , and therefore the foot support  52  on which the user&#39;s foot is positioned, towards the link mount  108 , thereby guiding the foot support  52  up in a desired gait pattern  110 . 
         [0063]    The gait amplitude may be altered by changing the relative position of the link mount  108  on the frame  36 . The top arc  112  shown in  FIG. 15  is a path of the connection of the compression link  100  to the first lower link  46  throughout the stance phase (when supporting the user&#39;s body weight). The bottom arc  114  is representative of the path of the connection of the compression link  100  to the first lower link  46  throughout the stance phase (when supporting the user&#39;s body weight) when the link mount  108  is lowered on the frame  36 . This may result in a path of travel represented by the second path  116  of travel of the foot supports  52 . This greater amplitude of foot travel may be representative of a running gait, as compared to a walking gait of the shorter path  110 . Therefore the desired gait pattern may be altered by changing the position of the link mount  108 . 
         [0064]    To further illustrate the function of the compression link  100 , the device  38 ″ with compression links  100  and cut away details are shown in  FIGS. 15-18 . In  FIG. 15  the second lower link  50  is shown in a elevated position as would be evident with a user with their foot on the foot supports  52  and their right foot at an approximate midpoint along the forward moving  118  swing phase of a walking gait. In this, the right foot of the user is likely unloaded as the user&#39;s weight is supported on the other (left) foot on the foot support of the first lower link  46 . The detail in the cutaway is shown in  FIG. 16  of the compression link  100  of this, the unloaded foot support  52  in the swing phase. The spring  106  of the compression link  100  is in a relaxed position as the shaft  102  is received within the sleeve  104 , not placing pressure on the spring  106 . 
         [0065]    In  FIG. 17 , the link mount  108  has been moved down to allow the foot supports  52  to achieve greater amplitude in their movement gait. In addition, the second lower link  50  and second upper link  48  have moved to position the corresponding foot support  52  in a position to simulate past heel strike and the beginning of the stance phase of a running gait, where the foot support  52  path of travel approximates the larger amplitude second path  116 . The detail cutaway in  FIG. 18  shows the spring  106  in a compressed state as compared to that of  FIG. 16 . This is due to the shaft stop  120  contacting one end of the spring  106  as it is trapped inside the sleeve  104 . Therefore as the shaft  102  extends out away from the sleeve  104 , the spring  106  is compressed, biasing the compression link  100  to a more retracted position. 
         [0066]    An alternative support system is shown in  FIGS. 19-22  in which the support system  99 ′ includes a support belt  122  movably coupled to the frame  36 . The belt  122  may be two separate but identical belts  122  positioned in a parallel arrangement proximal to the foot supports  52  so that when a foot support  52  descends to a predetermined height relative to the frame, a portion of the foot support  52  contacts the belt  122 , thereby limiting the bottom most position of the foot support  52 . One embodiment is shown in which there are two belts  122 , each supported by a front base pulley  124  and a rear base pulley  126 . It may be desired to provide elastomeric properties to the support of the foot supports  52 , as so suggested by the use of the compression spring  106  in the compression link  100 , as previously shown and described. In this embodiment, a similar cushioned support may be achieved by providing a belt  122  that includes elastic properties. As such, the belt  122  may flex or stretch as the foot support contacts an upper run  128  of the belt  122 . As the user provides force to the foot support during the stance phase of the gait the belt  122  may flex to allow some compliance to the load applied by the weight of the user. 
         [0067]    An alternative form of elastomeric support of the foot supports  52 , is to use a substantially non-elastic belt  122  as defined by little elongation of the belt  122  under load. An idler  130  may be provided with a bias member  132  positioned to maintain tension in the belt  122 . As is shown in  FIGS. 20 and 21 , when a foot support  52  makes contact with the upper run  128  of the belt  122 , the idler  130  is displaced to accommodate for the displacement in the upper run  128  of the belt  122  due to the normal load applied through the foot support  52 . 
         [0068]    The rear portion of the alternative support system  99 ′ is shown in detail in  FIG. 22 . The belts  122  are supported by the rear base pulleys  126 . If a brake or other resistance to movement of the foot supports  52  is required, a shaft drive  134  may be used to restrict the rotation of the rear base pulleys  126  and thereby the belts  122 , thus requiring work to be done by the user. As an alternative, the shaft drive  134  may also be a positive drive, thereby driving the rear base pulleys  126  and therefore the belts  122 . By driving the belts  122 , when a foot support contacts the upper run  128  of a belt  122 , the foot support  52  may be actively driven back as would normally be done when a user&#39;s foot moves during a running or walking gait. In that the foot supports  52  may be linked as previously noted, when one foot support  52  is moving in a posterior direction relative to the user, as a support foot would in a typical walking or running gait, the other foot support is elevated and moving in an anterior direction. This powered system may enable walking or running guidance for an impaired individual, thereby physically training the muscles. In addition, since the stride length is determined by the user, there is some neurological requirement for control by the user. In neurologically impaired individuals, such as stroke survivors, neurological training may be as important as muscular training. By adding a harness to support the weight of the user and eliminate falling, a system as shown and described may be more beneficial to the rehabilitation of neurologically impaired individuals than more costly and complex fully controlled ambulatory training devices. 
         [0069]    An alternative control system is shown in  FIGS. 23-25 . The training device  38 ′″ in this embodiment includes a frame  36 ″, which supports a first upper link  44 ″ connected to a first lower link  46 ″ and a foot support  52  on the lower end thereof. In a like manner, a second upper link  48 ″ may be provided which may be pivotally coupled to the frame  36 ″ and including a second lower link  50 ″ with a foot support  52  coupled to the second lower link  50 ″. A third transfer member  68 ″ may be coupled to the first lower link  46 ″ and another third transfer member  68 ″ coupled to the second lower link  50 ″. In this embodiment, the first upper link  44 ″ and the second upper link  48 ″ may each be mounted to an inside sprocket  136 . The third transfer members  68 ″ may be coupled to a transfer coupling  70 ″, which may be connected to an outside sprocket  138  by way of a shaft  140  journaled to the frame  36 ″. 
         [0070]    A first transfer system  54 ″ may be used to transfer the movement from the first upper link  44 ″ to the second upper link  48 ″ by way of the first transfer bar  62 ″, which may connect the inside sprockets  136  through the first transfer member  58 ″ and the second transfer member  60 ″. In this embodiment the first transfer member  58 ″ and the second transfer member  60 ″ may be in the form of a roller chain, belt or other pliable transmission member as opposed to a substantially rigid link as shown in previous embodiments. The direction of movement of the first transfer member  58 ″ may be substantially the opposite that of the second transfer member  60 ″ by way of the first gear  64 ′ coupled to the second gear  66 ′ in a radial orientation. The substantially opposite rotation of the first gear  64 ′ relative to the second gear  66 ′ drives the sprocket  141  in an opposite direction to that of the first transfer bar  62 ″. This combination enables a substantially reciprocating movement of the first upper link  44 ″ relative to the second upper link  48 ″. 
         [0071]    In this embodiment of the invention, the first lower link  46 ″ is in communication with the second lower link  50 ″ by way of the third transfer members  68 ″, as previously noted. The outside sprockets  138  drive the fourth transfer members  72 ″ to the second transfer system  56 ″, thereby linking the first lower link  46 ″ to the second lower link  50 ″. The second transfer system  56 ″ may include a second transfer bar  74 ″ to facilitate the transfer of power to the outside sprockets  138  and thereby to the first lower link  46 ″ and the second lower link  50 ″ by way of the third transfer members  68 ″. 
         [0072]    In this embodiment, substantially reciprocating motion of the first lower link  46 ″ to the second lower link  50 ″ may be achieved by a lower link control system  142 . With attention to  FIG. 25 , a drive motor  144  is used to provide torque to the second transfer bar  74 ″ by way of a drive belt  146  articulating a drive pulley  148  mounted to the second transfer bar  74 ″. A pair of clutches  150  may be used to regulate the torque output from the second transfer bar  74 ″, by way of the drive motor  144 , to the fourth transfer members  72 ″, which in turn apply force to the first lower link  46 ″ and the second lower link  50 ″. An advantage of such a lower link control system  142  is it may provide a capability to change the interaction between the first lower link  46 ″ and the second lower link  50 ″ that may be modified during use, according to the speed of movement, direction of movement and position in space of any of the leg links ( 44 ″,  48 ″,  46 ″ and  50 ″). This enables a dynamic system that may be altered by user gait or speed. One or more sensors may be used to determine the speed or movement or orientation of a leg link relative to any other leg link and a logic system to read this information and adjust the clutches  150  to alter the torque about the joint of the first lower link  46 ″ and the first upper link  44 ″ as well as the joint of the second lower link  50 ″ and the second upper link  48 ″. By varying these torques, a gait pattern of the user may be mimicked or supported by the device  38 ′″ to enable a smooth and comfortable exercise session by a user. 
         [0073]    Another embodiment of the device  38 ″″ is illustrated in  FIGS. 26-31 . A frame  36 ′″ supports a first upper link  44 ′″ and a second upper link  48 ′ about joints  152  and  154  respectively. A first lower link  46 ′″ may be pivotally coupled to the first upper link  44 ′″ at joint  156  and the second lower link  50 ′″ may be coupled to the second upper link  48 ′″ at joint  158 . A pair of foot supports  52  may be located on a distal end of the first lower link  46 ′″ and the second lower link  50 ′″. This linkage combination may be similar in function to that as previously disclosed herein. There is a support guide  160  coupled to each of the first lower link  46 ′″ and the second lower link  50 ′″, possibly near the foot supports  52 . The support guides  160  are each received by a guide rail  162 , each guide rail  162  may be moveably mounted to the frame  36 ′″ about a shaft  163 . The guide rails  162  may be made to move in a substantially reciprocating motion relative to one another by first transfer member  58 ′″ and a second transfer member  60 ′″. A first transfer system  54 ′″ includes a first transfer bar  62 ′″ that many connect a pair of pulley arms  164  on each end of the first transfer bar  62 ′″. The pulley arms  164  may include a pulley  166  adapted to engage each of the first transfer member  58 ′″ and the second transfer member  60 ′″. The pulley arms  164  may be located substantially on an opposite side of the first transfer bar  62 ′″ so that from a side view as one pulley  166  moves substantially forward, the other pulley  166  moves substantially backward. This causes displacement of the first transfer member  58 ′″ to be substantially opposite to that of the second transfer member  60 ′″, thereby enabling a substantially reciprocating action of the guide rails  162  one to the other and with it the support guides  160  and foot supports  52  mounted adjacent to the support guides  160 . 
         [0074]    Movement of the support guides  160  along the guide rails  162  may be controlled by a third transfer member  68 ′″ coupled to a lower portion of the support guides  160  and a fourth transfer member  72 ′″ coupled to an upper portion of the support guides  160 . The third transfer member  68 ′″ on each side of the device  38 ″″ as well as the fourth transfer members  72 ′″ are coupled to a second transfer system  56 ′″ which includes a second transfer bar  74 ′″. In this embodiment the third transfer members  68 ′″ and the fourth transfer members  72 ′″ may be a pliable structure such as a roller chain, a belt or strap. The third transfer members  68 ′″ and the fourth transfer members  72 ′″ may couple to the second transfer bar  74 ′″ by way of couplings  70 ″ in the form of sprockets or pulleys. This combination provides a substantially forward movement of one support guide  160 , and therefore associated foot support  52 , will result in a substantially rearward movement of the other support guide  160  and associated foot support  52 . The combination of the first transfer system  54 ′″ and the second transfer system  56 ′″ and the associated links enable a substantially reciprocating motion along the guide rails  162  and the generally vertical displacement of the guide rails  162  simultaneously, thereby offering a stable platform to perform an infinite number of gait pattern movements of a user positioned on the foot supports  52 . 
         [0075]    A resistance system  168  may also be provided to the second transfer system  56 ′″ as shown in  FIGS. 29-31  or to the first transfer system  54 ′″. The resistance system  168  may include a brake  170 , motor or any other form of resistance to resist the movement of the second transfer bar  74 ′″. A spring centering system  172  may be included in the first transfer system  54 ′″ to include a pair of springs  174  to guide the first transfer system  54 ′″ to a predefined position. 
         [0076]    Referring to  FIGS. 32-35  a device  38  produced in accordance with an alternative embodiment of the invention is shown. Some aspects of this embodiment are similar to those shown in previous figures are not designated with a unique prime value following the numerical designation. Similar to those embodiments previously noted a first upper link  44  is coupled to a first lower link  46  and a second upper link  48  is similarly coupled to a second lower link  50 . A pair of third transfer members  68 ′″ is in this embodiment, shown as rigid links, with a fixed length. As previously disclosed, these third transfer members  68 ′″ are coupled to the first lower link  46  and the second lower ling  50 , each with a second end coupled to a transfer coupling  70 . A pair of fourth transfer members  72  connects each of the two transfer couplings  70  to the second transfer system  56 ″″. In this embodiment the second transfer system  56 ″″ includes a second transfer bar  74 ″″ which includes a first ear  176  which is positioned substantially opposite to a second ear  178 . This substantially opposite orientation of the first ear  176  relative to the second ear  178  enables substantially opposite displacement of one of the fourth transfer member  72  to the other fourth transfer member  72 . 
         [0077]    A similar system may be used in the first transfer system  54 ″″ in which a first transfer bar  62 ″″ may be provided with a first bar ear  180  positioned substantially opposite to a second bar ear  182 . As with the second transfer system  56 ″″, the first transfer bar  62 ″″ of the first transfer system  54 ″″ provides substantially opposite displacement of the first transfer member  58  relative to the second transfer member  60 , thereby enabling substantially reciprocating movement of the first upper link  44  relative to the second upper link  48 . To assist and guide the user, a compression link  100  may be provided to limit the bottom movement of the foot support  52  under the foot of the user during the stance phase of the gait. As previously disclosed, the compression link  100  may include a spring or other bias member that provides a cushion to comply with the user&#39;s higher force during the middle of the stance phase of most gait patterns. In addition, the bias in the compression link  100  may assist with the recoil of the foot during the toe-off at the end of the stance phase and beginning of the swing phase of many running and walking gaits. As such the compression link  100  may be desired to use in this or other embodiments of the invention. 
         [0078]    An alternative resistance source has been provided in the form of a hydraulic damper  184 . This may be a one-way shock which provides resistance to compression thereby resisting the tendency of the first upper link  44  and the second upper link  48  to fall under the weight of the user. The recoil, or upward movement of the first upper link  44  and the second upper link  48  may not be restricted if the damper  184  offers little or no resistance to extension of the cylinder of the damper  184 . Any form of resistance commonly known in the art may be used in any number of locations including the first transfer system  54 ″″, the second transfer system  56 ″″, the fourth transfer members  72  or in this case, the first transfer member  58  and the second transfer member  60  near the attachment with the first upper link  44  and the second upper link  48  respectively. A restriction to movement of any part of the system may result in restriction to movement of the foot supports  52  in that the foot supports  52  may be connected through the linkage systems as shown and described. 
         [0079]    The foregoing detailed description of the present invention is provided for purposes of illustration, and it is not intended to be exhaustive or to limit the invention to the particular embodiment shown. The embodiments may provide different capabilities and benefits, depending on the configuration used to implement key features of the invention.