Abstract:
A gait trainer adapted for use with a treadmill and, optionally, a spinning cycle, provides greater accessibility for therapeutic and rehabilitative gait pattern training to individuals confronting injury, illness, or disability. The gait trainer is adjustable, to accommodate a wide variety of users with different stride lengths and needs.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of, and incorporates herein by reference in its entirety, U.S. Provisional Patent Application No. 62/315,955, which was filed on Mar. 31, 2016. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The invention relates generally to gait training for rehabilitation due to injury, illness, or disability. 
       BACKGROUND 
       [0003]    Repetitive pattern gait training addresses the problem of gaining or re-gaining walking function due to injury, illness, or disability by supporting and positioning the body while guiding the patient through biomechanically sound walking patterns. 
         [0004]    The common standard for weight supported gait training requires therapists to employ hands-on manipulation. Typically, a therapist stands or sits next to a patient and is actively involved in pushing, pulling, lifting, and generally guiding the patient&#39;s legs through the gait cycle. This approach is imprecise, labor intensive, rigorous for therapist/trainer, and is generally not sustainable for the many hours of repetition typically required to achieve lasting benefits. Capable gait training machines and devices are typically costly and therefore inaccessible to many who would benefit by using them. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention avoids costly electronics, hydraulics, and other complex systems. It is easy to setup and to use, and is affordable in a wide range of therapy and rehabilitation settings therefore making it more accessible than currently available gait training machines. Due to simplicity and elegance of the design, the present invention may be produced at lower cost, making it affordable to a wider range of facilities and accessible to a wider audience. 
         [0006]    The present invention automatically attains patient-specific length of stride, while also maintaining proper hip and knee flexion. The disclosed embodiments of the invention may also be used independently or in a therapist-assisted mode. In the latter mode, the device may be pedal-powered by a therapist, who provides variable and dynamic support (in amounts as needed) as patients work their way through the walking gait pattern. This variable input approach allows therapists/trainers to present patients with just the right amount of challenge, which supports progressive neuromuscular development, muscle and flexibility development, and muscle memory development. Moreover, the present device may also benefit therapists/trainers, as the device is easier to use, is less labor intensive, and because the therapists/trainers may more effectively introduce the right amount of challenge to support progress. 
         [0007]    In an aspect, embodiments of the invention relate to a gait trainer adapted for use with a treadmill. The gait trainer may include a pair of linkages, each linkage having a proximal end and a distal end; a pair of boots, each boot coupled to a proximal end of the respective linkage and adapted to receive a foot of a user; a support frame including a pair of pivot members to support the linkages and vertical guides for maintaining motion of the linkages in respective vertical planes; and a crank assembly coupled to the distal ends of the linkages; wherein rotation of the crank assembly translates into motion of the boots in a predetermined gait pattern. 
         [0008]    One or more of the following features may be included. The linkages may include tube stock. Each boot may include a cuff and an adjustable strap to accommodate the user&#39;s article of footwear. Each boot may connect to the proximal end of the respective linkage above the user&#39;s ankle. Each boot may further include a tether point to interconnect the boot to the support frame to control ankle angle to facilitate proper heel strike. Each boot may further include a tether disposed between an external rotation post and a forefoot area of the boot to control foot rotation to facilitate proper forefoot positioning. 
         [0009]    Each pivot member may include a wheel mounted below the respective linkage. Each wheel may be adjustable in a vertical direction to adjust hip and knee flexion of the gait pattern. The vertical guides may include vertical rollers. The crank assembly may include a pair of cranks and a distance between the couplings to the distal ends of the linkages defines a user&#39;s stride length. The distance may be adjustable to adjust the user&#39;s stride length of the gait pattern. 
         [0010]    The gait trainer may further include a pair of straps, each strap disposed between a top portion of the respective boot and the support frame to facilitate proper knee extension of the user. The gait trainer may further include a flywheel coupled to the crank assembly to facilitate smooth continuous motion by the user throughout the gait pattern. 
         [0011]    In another aspect, embodiments of the invention relate to a method for training gait of a user on a treadmill. The method may include the steps of affixing a pair of boots to the user on the treadmill; starting the treadmill; and constraining a gait pattern of the boots by controlling stride length, hip flexion, and knee flexion using a pair of linkages connected at proximal ends to the boots and at distal ends to a crank assembly. 
         [0012]    One or more of the following features may be included. The method may further include the step of facilitating proper heel strike by controlling ankle angle. The method may further include the step of facilitating proper forefoot position by controlling foot rotation. The method may further include the step of adjusting hip and knee flexion of the gait pattern. The method may further include the step of adjusting stride length. The method may further include the step of facilitating proper knee extension of the user. The method may further include the step of facilitating smooth continuous motion by the user throughout the gait pattern. 
         [0013]    The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0014]    In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which: 
           [0015]      FIGS. 1A and 1B  are schematic diagrams of an example of the gait training device in accordance with an embodiment of the invention; 
           [0016]      FIGS. 2A and 2B  are schematic diagrams of the vertical rollers and pivot members of the gait training device in accordance with embodiment of the invention; 
           [0017]      FIG. 3  is a perspective view of the gait training device in accordance with an embodiment of the invention; 
           [0018]      FIG. 4  is a schematic diagram of the boot-linkage assembly of the gait training device in accordance with embodiment of the invention; 
           [0019]      FIGS. 5A-5D  are schematic diagrams of the boot of the gait training device in accordance with an embodiment of the invention; 
           [0020]      FIGS. 6A and 6B  are schematic diagrams of the boot of the gait training device in accordance with an embodiment of the invention; and 
           [0021]      FIG. 7  is a diagram showing the path traveled by the foot during a user&#39;s stride. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The gait training device according to various embodiments is adapted to assist a patient in the gaining or re-gaining of walking function, which may have been lost due to illness, injury, or disability. Embodiments of the gait training device are less expensive than currently available gait training devices, making the described gait training device more accessible to patients. 
         [0023]    The gait training device  100 , shown in  FIG. 1 , works in conjunction with a conventional treadmill  102 . In one embodiment, a spinning cycle  104  is positioned directly behind the treadmill  102 . Linkages  106   a,    106   b  may be affixed at respective distal ends to a crank assembly  108  of the spinning cycle  104  and at respective proximal ends to the device&#39;s boot connection  110   a,    110   b  above the ankle and behind the patient&#39;s calf. The boots  112   a,    112   b,  shown in  FIGS. 5A-5D, 6A, and 6B , will be described in further detail below. The linkages  106   a,    106   b  are confined to move in vertical planes by vertical rollers  114  held in a support frame  116 . 
         [0024]    The linkages  106   a,    106   b  may be formed of a stiff material, e.g., aluminum, and may be four to five feet long. In some embodiments the cross section of the linkages is a square. In others it is a circle. In some embodiments, the linkage may be coupled with a flat surface  118  to facilitate smooth movement over respective pivot members  220   a,    220   b  (shown in  FIGS. 2A  and  2 B) such as wheels or rollers. In some embodiments, the linkages  106   a,    106   b  may move in a counterclockwise fashion. The length of the spinning cycle crank  107  may be changed to adjust for longer or shorter stride length. For example, a 100 mm crank length may be suitable for most adult users. 
         [0025]      FIG. 1B  shows an enlarged perspective view of the gait training device  100  without the treadmill  102 . 
         [0026]    Referring to  FIGS. 2A and 2B , the support frame  116  placed between the spinning cycle  104  and the treadmill  102  aligns the linkages  106   a,    106   b  using vertical rollers  114 . These vertical rollers  114  keep the linkages  106   a,    106   b  parallel to each other, prevent the stance of the user (stride width) from getting too wide, and prevent scissoring, as well as hip abduction/adduction. 
         [0027]    The support frame  116  also includes two pivot members  220   a,    220   b  placed underneath each linkage  106   a,    106   b  and between the vertical rollers  114 . The pivot members  220   a,    220   b  allow the linkages  106   a,    106   b  to pivot as the crank assembly  108  is turned, thereby mimicking the path a foot travels during a walking gait at the proximal end of the linkage. These pivot members  220   a,    220   b  can be raised or lowered to induce more or less hip and knee flexion. In some embodiments, each pivot member  220   a,    220   b  may be a rubber wheel. 
         [0028]    The present invention turns circular, rotary motion into up/down/forward/backward foot, leg, and hip movement with adjustable flexion and extension to accommodate length and height of the individual patient&#39;s stride. As the treadmill  102  begins to move the stance phase leg may be driven backward (in conjunction with the direction of movement of the treadmill deck) and the cycle  104  spins in a reverse motion. The other linkage propels the swing leg forward and upward, to achieve a chosen length of stride, hip flexion, and knee flexion consistent with a successful gait cycle. 
         [0029]    As the treadmill  102  moves, the stance leg drives the crank assembly  108  arm, which in turn drives the other linkage. The linkages  106   a,    106   b  come into contact with pivot members  220   a,    220   b  in the support frame  116  in a levering action, which raises and lowers the height of the linkages  106   a,    106   b  where they contact the boot  110   a,    110   b,  thereby lifting and driving the patient&#39;s legs. 
         [0030]    In some embodiments, the device  100  may be effective using the speed and power of a treadmill  102  without an additional motor. In other embodiments, the device  100  may be pedal-assisted by a therapist or trainer to help the patient though stride hitches, to address strength and flexibility issues, and improve the patient&#39;s walking rate. 
         [0031]    The present invention may also be used with modified spinning cycles with heavy (40 lbs. or greater) flywheels. In some embodiments, the flywheels create rotational inertia, which helps the patient continue walking at points in their gait where they have the most difficulty. If the patient needs help with timing or getting the unit to work independently, a therapist or trainer may pedal the device to help influence better gait. The present invention may be used in conjunction with a weight support harness to support the patient on the treadmill  102 . 
         [0032]    Another view of the gait training device  100  is shown in  FIG. 3 . Here, the linkages  106   a,    106   b  are in a mid-stride position. In some embodiments, the pivot members  220   a,    220   b  act as fulcrums for the linkages  106   a,    106   b.  As indicated by the arrow  322 , each boot  112   a,    112   b  may rotate about an axis parallel to the respective linkage  106   a,    106   b,  which facilitates a greater range of motion in the user. At the farthest forward extent of motion, the linkage  106   a,    106   b  no longer rests on the pivot member  220   a,    220   b,  and remains above and out of contact with the pivot member  220   a,    220   b  throughout the stance phase of the gait while the patient&#39;s feet are on the treadmill  102 . 
         [0033]    Referring to  FIG. 4 , the boot  112  may also pivot about an axis perpendicular to the linkage and parallel to the ground. This pivot allows the boot  112  to be adjustable with respect to lower leg angle to address issues of valgus or varus stress at the knee. 
         [0034]    As depicted in  FIGS. 5A-5D , the patient may be connected to the linkages  106   a,    106   b  via adjustable boots  112   a,    112   b  designed to fit over shoes inclusive of patient-specific braces or other ankle foot orthosis (AFO) devices. The lower leg may be captured by the boot  112  and fastened to the leg using ratcheting binding straps  524  and/or hook and loop fasteners  526  connected to aluminum cuffs  528 . In some embodiments, the boot  112  may be a shell that fits over patient orthoses, bracing, and/or shoes (shown in  FIGS. 6A and 6B ) and may contribute to proper ankle rotation and controlled heel strike. 
         [0035]    In some embodiments, an external rotation post  530  extends laterally from the back of the boot and connects to a hook and loop muzzle  526  on the forefoot. The hook and loop muzzle  526  secures the forefoot area. In some embodiments, a lateral tether  532  provides tension from the muzzle  526  laterally to the external rotation post  530  to insure proper foot positioning. This aid pulls the foot into proper external rotation to prevent excessive internal rotation and may be helpful in introducing additional dorsi-flexion. 
         [0036]    The top of the boot may be tethered to a point on the device in order to force a firm heel strike, shown in  FIGS. 5C and 5D . A cord and/or tether  534  may be attached to the back of the boot  112 . The tether  534  may be a strap or elastic cord. The boot connection may be designed to influence both the ankle and the calf. Based on patient needs, the top rear of the boot may be connected to high point on the device by the tether  534  in some embodiments. When tightened, this tether pulls back just below the knee to induce appropriate knee extension at terminal swing or initial contact. 
         [0037]    Referring to  FIG. 7 , traces A, B, and C show the path that the boot  112  travels at the connection point  110  (Trace A), the midfoot region (Trace B), and the toe. The connection point  110  and midfoot region of the user travel similar paths. Trace C demonstrates that the device  100  facilitates a proper gait, with the toe pointing upward at the heel-strike phase of the stride. 
         [0038]    As previously described, the gait trainer transforms circular, rotary motion of the crank assembly into a repeatable up/down/forward/backward gait pattern. As shown, the crank assembly traces a circle in a counterclockwise direction while in use. As the crank assembly turns, the proximal end of the linkage attached to the boot begins to trace a circle, which is then cut off at a flat line as the boot comes in contact with the treadmill. This motion, however, may not be fully constrained as the linkages are free to lift off the pivot members. 
         [0039]    More particularly,  FIG. 7  depicts an example of three trace patterns, taken at three points along the boot portion, for a particular user during a gait training session. Pattern A is a trace of the connection point at the proximal end of the linkage to the boot. Pattern B is a trace of a point generally located at the midfoot portion of the user. Pattern C is a trace of a point generally located at the toe portion of the user. As can be expected, there is close correlation between patterns A and B, with some variability (i.e., lessening of the height of the upper arcuate portion of pattern B) due to pivoting at the connection point to accommodate the user&#39;s personal gait. This effect is more apparent at the toe, depicted in pattern C, due to the combined effect of the pivoting of the connection and changes in the user&#39;s ankle angle, at toe off and elsewhere in the swing phase through heel strike. 
         [0040]    These pattern variations are user-dependent and provide each user some freedom of movement (within limits) within the broader constraints of the gait trainer gait pattern and associated training methodology. The influence of the gait trainer at connection point A is greater than at other points, allowing sufficient freedom of movement at points remote therefrom (e.g., at the midfoot point B and the toe point C) to engage one&#39;s personal gait and accommodate users of different capabilities, for example, individuals who tend to point or drag toes. Nonetheless, the gait trainer provides the necessary safety net for safe, reliable gait pattern training. 
         [0041]    Table 1 is a table of minimum, maximum, and typical values for parameters associated with various embodiments of the invention. These values are meant to be exemplary in nature for teenagers and adults of normal stature and body proportions; however, lower and higher values are considered to be within the teachings and scope of the invention to manufacture systems for others, such as children. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Min 
                 Nominal 
                 Max 
                   
               
               
                 Feature 
                 Val. 
                 Val. 
                 Val. 
                 Unit 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Diameter of crank assembly 
                 100 
                 200 
                 300 
                 cm 
               
               
                 Length of linkage 
                 48 
                 54 
                 66 
                 in 
               
               
                 Height adjustment of pivot 
                 −2 
                 0 
                 +2 
                 in 
               
               
                 wheels 
               
               
                 Distance between crank axis of 
                 22 
                 28 
                 34 
                 in 
               
               
                 rotation and pivot wheels 
               
               
                 Ratio of diameter of crank 
                 2:3 
                 1:1 
                 3:2 
               
               
                 assembly to diameter of stride 
               
               
                 length 
               
               
                 Stride length 
                 100 
                 200 
                 300 
                 cm 
               
               
                   
               
             
          
         
       
     
         [0042]    The terms and expressions employed herein are used as terms and expressions of description and not of limitation and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof. In addition, having described certain embodiments of the invention, it will be apparent to those of ordinary skill in the art that other embodiments incorporating the concepts disclosed herein may be used without departing from the spirit and scope of the invention. The structural features and functions of the various embodiments may be arranged in various combinations and permutations, and all are considered to be within the scope of the disclosed invention. Unless otherwise necessitated, recited steps in the various methods may be performed in any order and certain steps may be performed substantially simultaneously. Accordingly, the described embodiments are to be considered in all respects as only illustrative and not restrictive. Furthermore, the configurations described herein are intended as illustrative and in no way limiting. Similarly, although physical explanations have been provided for explanatory purposes, there is no intent to be bound by any particular theory or mechanism, or to limit the claims in accordance therewith.