Patent Publication Number: US-8992393-B2

Title: Change of direction machine and method of training therefor

Description:
This application claims priority to U.S. patent application Ser. No. 12/858,821, filed Aug. 18, 2010, now pending, the disclosure of which is hereby incorporated by reference as if set forth fully herein, and U.S. Provisional Patent Application No. 61/348,164, filed May 25, 2010, the disclosure of which is hereby incorporated by reference as if set forth fully herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to exercise equipment and in particular to a training machine and method therefor. 
     The squat exercise is an effective and popular exercise for strengthening the lower body, but not well suited for dynamic athletic training. In addition, squats employ an up and down motion which is confined and limiting. Moreover, squats must be carefully performed because the risk of injury is high. This is especially so given that squats are typically performed while carrying weights and the weight is freely supported by the user supporting the weighted bar across the back of the neck and shoulders. 
     A number of exercise aids have been developed to reduce the risk of injury when performing squats. For example, weights used during squats may be guided by two vertical rails which prevents the weights from moving forward, sideways, backwards, or dropping too far. However, this arrangement suffers from several disadvantages. One such disadvantage is that the vertical rails which support and guide the bar prevent motion of the bar in any direction but straight up and straight down. This creates an un-natural motion for the knee and back, leading to injury or ineffective exercise. 
     Another solution is to utilize a human spotter on each end of the free bar to grab the weight should the lifter lose balance. While this is one possible solution, it does not prevent injury to the knees and back and is only as good as the spotters themselves. Moreover, a spotter is not always available when lifting and the range of motion for the lifter is still primarily limited to up and down, although leaning forward or backward is possible, which increases the chance of injury. 
     From the discussion that follows, it will become apparent that the present invention addresses the deficiencies associated with the prior art while providing numerous additional advantages and benefits not contemplated or possible with prior art constructions. 
     SUMMARY OF THE INVENTION 
     The change of direction machine disclosed herein provides unique training to strengthen and tone various muscles and body structures of its users. In one or more embodiments, the machine may be directed to the muscles and body structures of the lower body as well as the torso or core of a user. As will be described further below, the machine provides a structure and operation which trains of the muscles and body structures used in changing the direction of one&#39;s movement, as well as other muscles and body structures. The machine is highly beneficial in that it can provide resistance to a user for a wide range of user motions. In addition, the machine provides safety and convenience improvements over other exercises and exercise devices. 
     The change of direction machine may have a variety of configurations. For instance, in one embodiment the machine may be an exercise machine comprising an arm assembly having a pivoting end and an engagement end configured to engage one or more shoulders of a user, a support structure configured to support the arm assembly at the pivoting end. The arm assembly may extend outward from the support structure and be rotatable at the pivoting end relative to the support structure. It is contemplated that the exercise machine may also include a pivot at the pivoting end of the arm assembly. The pivot may be configured to allow the arm assembly to rotate relative to the support structure in a plurality of horizontal and vertical directions. It is noted that the arm assembly may include a locking mechanism configured to engage to lock the arm assembly in position and to disengage to unlock the arm assembly. 
     A resilient resistance device coupled at a first end to the arm assembly and coupled at a second end to the support structure may be provided to provide a resistance to the user. A tension adjuster movable along a length of the arm assembly may be provided as well. The first end of the resistance device may be coupled to the tension adjuster to allow resistance provided by the arm assembly to be adjusted. The tension adjuster may comprise a ratcheting mechanism configured to move and secure the tension adjuster in place along the length of the arm assembly. 
     The exercise machine may comprise one or more pads at the engagement end of the arm assembly configured to engage one or more shoulders of the user. The one or more pads are rotatably mounted to the arm assembly at the engagement end. In these cases, one or more range limiters may be at the engagement end of the arm assembly to prevent lateral movement of the one or more pads. 
     In another embodiment the change of direction machine may be an exercise machine comprising a pivoting arm configured to provide a downward resistance to a user, and a support structure configured to stabilize the exercise machine. The pivoting arm may extend outward from the support structure, and be held at an elevated position by the support structure while being rotatable in a plurality of directions relative to the support structure. 
     A resilient resistance device having a first end and a second end may be provided to generate a resistance for the user. The first end may be attached to the pivoting arm while the second end may be attached to the support structure. To adjust the tension of the resistance device, a tension adjuster movable along said pivoting arm may be included. The first end of the resilient resistance device may then be attached to said tension adjuster to allow the tension of the resilient resistance device to be adjusted. 
     Similar to the above embodiment, this exercise machine may comprise one or more pads at an engagement end of the pivoting arm configured to engage an upper body of the user. Alternatively or in addition, the machine may comprise one or more rotating pads at an engagement end of the pivoting arm. The one or more rotating pads may be configured to engage an upper body of the user, while being limited from rotating laterally. 
     A locking mechanism configured to engage to lock the arm assembly in position and to disengage to unlock the arm assembly may also be provided. It is contemplated that the locking mechanism may comprise a locking member coupled with the pivoting arm and a stop coupled with the support structure. The stop may comprise an open top portion to permit upward movement of the pivoting arm even when the arm assembly is locked. 
     A method of training a user on a change of direction machine is also disclosed herein. In one embodiment, the method may comprise engaging an engagement end of a pivoting arm assembly at a portion of the user&#39;s upper body, lowering the upper body to a lowered position by bending at the knees while resisting the resistance applied to the upper body, and raising the upper body to a raised position by extending at the knees and waist to overcome the resistance applied to the upper body. Lowering and raising the upper body in this manner rotates the pivoting arm assembly in a vertical direction, and may occur without moving the upper body in a forward or backward direction so as to prevent injury. The pivoting arm assembly may be configured to provide a resistance to the user in a downward direction such that the resistance may be applied to the user as the upper body is lowered and raised. 
     It is noted that a locking mechanism of the pivoting arm assembly may be disengaged to unlock the pivoting arm assembly prior to using the machine. It is also noted that the method may include adjusting the resistance of the machine. Where the resistance is provided by a resistance device attached to a tension adjuster, such adjustment of resistance may occur by moving the tension adjuster along the length of the pivoting arm assembly. 
     The method may include moving laterally while lowering the upper body. Moving laterally in this manner rotates the pivoting arm assembly in a horizontal direction allowing the resistance to continue to be applied to the user during the lateral motion. The lateral motion may occur in a variety of ways. For example, in one embodiment moving laterally may entail taking a step with a first foot in a lateral direction, moving at least the upper body in the lateral direction while lowering the upper body, and moving a second foot towards the first foot such that the first foot and second foot are adjacent. The user may also move in various lateral directions. For example, the method may comprise moving laterally in a first direction while lowering the upper body one or more times, and moving laterally in a second direction while lowering the upper body one or more additional times. Moving laterally in the first direction and moving laterally in the second direction may accordingly rotate the pivoting arm assembly in a first horizontal direction and a second horizontal direction. 
     Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1A  is a side perspective view of an exemplary change of direction machine; 
         FIG. 1B  is a perspective view of an exemplary support structure of a change of direction machine; 
         FIG. 2A  is a perspective view of an exemplary arm assembly of a change of direction machine; 
         FIG. 2B  is a perspective view of an exemplary locking mechanism and tension adjuster of a change of direction machine; 
         FIG. 2C  is a perspective view of an exemplary locking mechanism and tension adjuster of a change of direction machine; 
         FIG. 2D  is a perspective view of an exemplary locking mechanism and tension adjuster of a change of direction machine; 
         FIG. 2E  is a perspective view of an exemplary locking mechanism and tension adjuster of a change of direction machine; 
         FIG. 3A  is a perspective view of an exemplary tension adjuster of a change of direction machine in operation; 
         FIG. 3B  is a perspective view of an exemplary tension adjuster of a change of direction machine in operation; 
         FIG. 3C  is a perspective view of an exemplary tension adjuster and return mechanism of a change of direction machine in operation; 
         FIG. 3D  is a perspective view of an exemplary tension adjuster and return mechanism of a change of direction machine in operation; 
         FIG. 3E  is a perspective view of an exemplary tension adjuster of a change of direction machine; 
         FIG. 4A  is a top perspective view of an exemplary engagement end of a arm assembly; 
         FIG. 4B  is a perspective view of an exemplary engagement end of a arm assembly; 
         FIG. 4C  is a perspective view of an exemplary engagement end of a arm assembly; 
         FIG. 4D  is a perspective view of an exemplary pivoting engagement end of an arm assembly; 
         FIG. 4E  is a perspective view of an exemplary pivoting engagement end of an arm assembly; 
         FIG. 4F  is a perspective view of an exemplary adjustable engagement end of an arm assembly; 
         FIG. 4G  is a perspective view of an exemplary adjustable engagement end of an arm assembly; 
         FIGS. 5A-5C  are side views illustrating exemplary use of a change of direction machine; 
         FIGS. 6A-6C  are top views illustrating exemplary use of a change of direction machine; 
         FIG. 7A  is a perspective view of an exemplary arm assembly with fixed weights; 
         FIG. 7B  is a perspective view of an exemplary arm assembly with fixed weights. 
         FIG. 8  is a perspective view of an alternate embodiment of a change of direction machine; 
         FIG. 9  is a perspective view of an alternate embodiment of a change of direction machine; 
         FIG. 10A  is a perspective view illustrating exemplary use of an alternate embodiment of a change of direction machine; 
         FIG. 10B  is a perspective view of an alternate embodiment of a pivot and locking mechanism of a change of direction machine; 
         FIG. 11  is a perspective view illustrating exemplary use of an alternate embodiment of a change of direction machine; 
         FIG. 12  is a perspective view illustrating exemplary use of an alternate embodiment of a change of direction machine with calf block extended; 
         FIGS. 13A and 13B  are side views illustrating exemplary use of an alternate embodiment of a change of direction machine; 
         FIGS. 14A and 14B  are side views illustrating exemplary use of an alternate embodiment of a change of direction machine; and 
         FIGS. 15A through 15C  are top views illustrating exemplary use of an alternate embodiment of a change of direction machine. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following description, numerous specific details are set forth in order to provide a more thorough description of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without these specific details. In other instances, well-known features have not been described in detail so as not to obscure the invention. 
     In general, the change of direction machine herein provides a resistance which enhances the effectiveness of squats. The resistance may be applied to a user&#39;s upper body like the force provided by weights used with traditional squats. The change of direction machine&#39;s resistance is unique however in that it moves with the user&#39;s body during squats. In this manner, the change of direction machine conforms to the user&#39;s natural body movements. This allows effective training while greatly reducing the risk of injury. 
     Whereas traditional squats using free weights may be difficult for beginners to perform, the structure and design of the present invention allows even the non-accomplished and non-experienced users to perform weight lifting, and other related or similar exercises, safely and effectively. This is highly advantageous in that it is exceedingly difficult to maintain proper, let alone, perfect form as one becomes fatigued from training during traditional weight lifting exercises. This is especially so with traditional squats with free weights. In addition, as the user becomes fatigued, the risk of injury increases because the user lacks the strength to maintain proper form. Good form and proper performance are more easily and readily attained through use of the present invention, and the user can more readily train for longer periods of time using the present invention. 
     The change of direction machine may allow hands free operation in one or more embodiments. That is, unlike in traditional squats, the user need not hold one or more weights during training. This reduces fatigue allowing the user to focus his or her energy on lower body training. In addition, the change of direction machine is safer because the risks associated with dropping or falling weights are eliminated. Moreover, the change of direction machine is also more convenient in that the user may perform squats without the need for an assistant or spotter. 
     For these and other reasons (which are disclosed below), the change of direction machine provides “ergomechanics” which improve the ergonomic comfort and convenience for the user while also providing enhanced training and better results for the user. 
     In one or more embodiments, the change of direction machine may be configured to allow performance of one or more enhanced squats. In general, the enhanced squats have a much larger range of motion than traditional squats, and have greatly reduced risk of injury. For instance, as will be described further below, the resistance provided by the change of direction machine allows for one or more enhanced squats including a wide range of lateral motions to be performed. The ability to make these motions quickly and with strength is highly beneficial to building lower body muscles as well as to improve speed and agility in sports such as tennis and basketball, among others. 
     Referring to  FIG. 1A , the change of direction machine comprises a support assembly  104  and an arm assembly  108 . The support assembly  104  is generally configured to support or hold one or more elements of the change of direction machine. In one or more embodiments, the support assembly  104  may be configured to provide a stable base for the change of direction machine and to position the arm assembly  108  at an elevated position for use. 
     In one embodiment, the support assembly  104  may comprise a structure to support the elements of the change of direction machine. As can be seen in  FIG. 1A  for example, the support assembly  104  is configured as a frame  116  which holds the arm assembly  108  and other components of the change of direction machine. As can also be seen, the support assembly  104  is configured to provide a base which holds the arm assembly  108  stably even though the arm assembly extends or cantilevers outward from its attachment point to the base. It is contemplated that the support assembly  104  may be secured to the ground, a wall, or other structure to improve stability if desired. 
     The arm assembly  108  may be held or supported at various elevations. For example, as shown, the arm assembly  108  is elevated between 5 and 6 feet off the ground. Of course, other heights are possible. In one embodiment, the arm assembly  108  may be at or near % of a user&#39;s height. In another embodiment, the arm assembly  108  may be at or near the level of a user&#39;s shoulders. The arm assembly  108  may be fixed at a elevation or may be adjusted to be secured at various elevations, as will be described further below. 
     The support assembly  104  may have a low center of gravity in one or more embodiments to allow the arm assembly  108  to extend therefrom without causing the change of direction machine to tip or become unstable, especially when the machine is in use. In addition, the support assembly may be relatively compact in one or more embodiments. This provides a space around the change of direction machine in which a user can move freely. For example, a user may engage the arm assembly  108  and move around the support assembly  104  without risk of contacting the support assembly while training. 
     The arm assembly  108  may be configured in a variety of ways. In one embodiment shown in  FIG. 1A , and more particularly in  FIGS. 2A through 2E , the arm assembly  108  comprises a cantilever  124  attached at a pivoting end  136  to the support assembly  104  by a pivot  120 . The user may engage the arm assembly  108  at an engagement end  140  of the arm assembly  108 . One or more pads  128  may be at the second end of the arm assembly  108  to allow a user to comfortably engage the arm assembly. 
     The pivot  120  may be configured to allow the engagement end  140  of the arm assembly  108  to move in a variety of directions. For instance, the arm assembly  108  may be moved horizontally, vertically, or both in one or more embodiments. This is highly advantageous in that it permits a variety of training to be performed on the change of direction machine. For example, a traditional squat may be performed by lifting and lowering the arm assembly  108  vertically. The change of direction machine also allows enhanced squats to be performed. For example, an enhanced squat may be performed by lifting and lowering the arm assembly  108  vertically while also moving in a lateral direction, as will be described further below. 
     The pivot  120  may be various structures that allow the engagement end  140  of the arm assembly  108  to be moved. In one or more embodiments, the pivot  120  may be configured to allow movement along multiple or any axis. As shown for example, the pivot  120  is configured as a ball joint which allows the arm assembly  108  to be moved along any axis. Alternatively, a universal joint may be used. Of course, other unions may be used. For example, a single axis joint such as a hinge joint may be used in some embodiments. The hinge joint may be rotatably mounted to allow movement along more than one axis. For example, the hinge joint may be coupled to another hinge joint to allow movement along more than one axis. 
     An alternate embodiment of the arm assembly  108  can be seen on the alternate embodiment change of direction machine shown in  FIGS. 8 and 9 , for example. Here, arm assembly  108  comprises a cantilever  124  attached to a connector bar  502  by way of a hinge  501  on one end, and adjuster bar  503  on the other end. Connector bar  502  is connected to support assembly  104  by way of a pivot  120 , which, in this alternate embodiment, is a hinge joint rotatably mounted to allow movement along more than one axis. The detail of pivot  120  can be seen in  FIG. 10A , and more particularly in  FIG. 10B . Referring to  FIG. 10B , pivot  120  comprises a hinge  504  that is attached to the connector bar  502 . Hinge  504  is fitted through the joint  505 , which itself can turn or spin along its longitudinal axis. As such, connector bar  502  (and correspondingly, cantilever  124  and assembly arm  108 ) can be moved in an upward or downward direction as well as laterally in a left to right, or right to left direction. 
     As can be seen, the position of the pivot  120  on the support assembly  104  may determine the elevation or raised position of the arm assembly  108 . For example, as shown in  FIG. 1A , the pivot  120  is positioned at the top of the support assembly  104 . The position of the pivot  120  on the support assembly  104  may be fixed or adjustable according to various embodiments of the change of direction machine. For example, the pivot  120  may be fixed at the top of the support assembly  104  to give the arm assembly  108  a fixed elevation. 
     Alternatively, the pivot  120  may be configured to be raised and lowered to accordingly raise and lower the arm assembly  108 . As shown in  FIG. 1A , the pivot  120  may be mounted to a pivot support  148  of the support assembly  104 . The pivot support  148  may be raised and lowered in one or more embodiments. It will be understood that this may be accomplished in various ways. For example, in  FIG. 1B , the pivot support  148  comprises a sleeve and tube structure where an outer sleeve  152  and inner tube  156  can slide or move relative to one another to lengthen (i.e., raise) and shorten (i.e., lower) the pivot support. Once at the desired height, the sleeve  152  and inner tube  156  may be secured in position relative to one another. For instance, in  FIG. 1B , a pin  160  may be inserted through an opening of the sleeve  152  and inner tube  156  to secure them. Of course, the sleeve  152  and inner tube  156  may be secured in other ways in addition to or instead of the pin  160 , such as by one or more clips, clamps, screws, or the like. 
     Alternatively, in the alternative embodiment change of direction machine shown in  FIGS. 8 and 9 , for example, the height of arm assembly  108  can be adjusted in another manner. Here, referring to  FIGS. 9 ,  10 A, and  10 B, the height of the cantilever  124  is modified by way of a pin  508  that is fitted through adjuster bar  503 . Cable  507  is attached at one end to pin  508 , and to handle  506  on the other end (as can be seen more particularly in  FIG. 9 ). When the user applies pressure to handle  506 , for example as shown in  FIG. 10A , the pin  508  becomes disengaged from the adjuster bar  503 , and the user is then able to move cantilever  124  up or down, which correspondingly increases or decreases, respectively, the relative distance between cantilever  124  and connector bar  502 , as well as the overall height of arm assembly  108  relative to the ground. Once the desired height of arm assembly  108  is achieved, the user releases the pressure from handle  506 , which causes pin  508  to reengage with adjuster bar  508 , thus locking arm assembly  108  at the desired height. 
     The ability for the arm assembly  108  to be raised and lowered is advantageous in that it allows users of various heights to use the change of direction machine. In this manner, the change of direction machine can accommodate taller as well as shorter users. In addition, the arm assembly  108  can be positioned at or near the level of the user&#39;s shoulders, whatever that may be, making it easier for the user to engage the machine. 
     As described and discussed, the arm assembly  108  may comprise a locking mechanism in one or more embodiments. In general, the locking mechanism is used to secure the arm assembly  108  in place when not in use. This is beneficial because the pivot  120  of the arm assembly  108  would otherwise allow the arm assembly to move in a variety of directions. To illustrate, in  FIG. 1A , the arm assembly  108  is locked in a substantially horizontal position. This position may be achieved through use of the locking mechanism. 
     The locking mechanism is beneficial in that it positions the arm assembly  108  in a convenient position. As can be seen in  FIG. 1A , the user can easily engage the engagement end  140  of the arm assembly  108  in its locked position. Of course, the locking mechanism may hold the arm assembly  108  in a variety of positions. Typically, the arm assembly  108  will be held substantially horizontal to allow the user to easily engage the arm assembly by stepping into and/or under the pads  128 . In this manner, the user may engage the arm assembly  108  without having to first lift the arm assembly. 
     The locking mechanism may be configured in various ways. In one embodiment, a first portion of the locking mechanism may engage a second portion of the locking mechanism to secure the arm assembly  108  in place. Once engaged, the first portion, second portion, or both may physically hold the arm assembly  108  in place, or may prevent certain movement(s) of the arm assembly. 
     Exemplary locking mechanisms are illustrated in  FIGS. 2A-2E .  FIG. 2A  is a perspective view of the arm assembly  108  showing the locking mechanism. In one or more embodiments, the locking mechanism may comprise a coupler  224 . Of course a plurality of couplers  224  may be used. To illustrate, the embodiment shown has two couplers  224  with a coupler on each side of the arm assembly  108 . The coupler  224  may comprise two separate structures that engage to secure the arm assembly  108  in place. For example, the coupler  224  may comprise a stop  220  that may be engaged by a locking member  204  to secure an arm assembly  108  in place. When engaged, physical contact between the stop  220  and locking member  204  may prevent undesired movement of the arm assembly  108 . 
     In one or more embodiments, the locking member  204  may be attached to the arm assembly while the stop  220  may be attached to the support assembly  104 . In this manner, when engaged, the coupler  224  secures the arm assembly  108  in position relative to the support assembly  104 . As can be seen, the locking member  204  is attached to the arm assembly  108  and the stop  220  is attached to the support assembly  104 . 
     Referring to  FIG. 2B , it can be seen that the end  212  of the locking member  204  may have a shaped end in some embodiments. For instance, in  FIG. 2B , the end  212  has a square shape at one end. This allows the locking member  204  to engage the planar stop  220  as shown. The planar features of the locking member  204  and stop  220  are in close physical contact when engaged. This limits the motion of the locking member  204  and the stop  220  relative to one another and, in turn, limits the motion of the arm assembly  108 . 
     Of course, the end  212  or other portion of the locking member  204  may be formed in various shapes. For example, the end may be round, flat, rectangular, polygonal, or other shapes. The stop  220  may have a corresponding shape to accept or engage the locking member  204 . For example, the stop  220  may be curved or comprise a round opening to accept or engage a round locking member to hold the arm assembly  108  in position. 
     It is noted that the coupler  224  may allow some upward movement of the arm assembly  108  even when the coupler is engaged. This is beneficial in that it allows a user to engage the engagement end  140  of the arm assembly  108  and stand up straight without having to first unlock the arm assembly by disengaging the coupler  224 . To illustrate, in  FIG. 2B , the stop  220  is configured as a shelf-like structure with an open area above. In this manner, the stop  220  prevents the arm assembly  108  (when locked) from moving downward, but allows at least some upward movement. This allows the user to stand up straight and brace him or herself to hold the arm assembly  108  before the arm assembly is unlocked. 
     The locking member  204  of the coupler  224  may be movable so as to allow the locking member to engage and disengage the stop  220 . This may be achieved by one or more mounts  216  that allow the locking member  204  to move to engage and disengage the stop  220 . As shown in  FIG. 2B , the mount  216  comprises an open structure which allows the locking member  204  to slide or move within the mount to engage and disengage the stop  220 . In  FIG. 2B , the locking member  204  and stop  220  have been engaged. As  FIG. 2C  shows, to disengage the stop  220 , the locking member  204  may be slid or otherwise moved away from the stop, releasing the arm assembly  108 . It will be understood that the mount  216  may be configured as various guides, tracks, and the like to allow the locking member  204  to engage and disengage the stop  220 . 
     Referring back to  FIG. 2A , the locking mechanism may provide one or more handles  208  to allow the user to more easily use the locking mechanism. It is noted that handles  208  may not be present in all embodiments because the user may directly engage the locking mechanism. If included, the handles  208  may be attached to the locking members  204  such that they are located near or at the engagement end  140  of the arm assembly  108  to allow the user to conveniently access the handles. The locking members  204  may be elongated in one or more embodiments, to allow the handles  208  to be located near the user. 
     In operation, the user may grasp the handles  208  and move the locking members  204  to engage the stop  220  (as shown in  FIG. 2C ) to lock the arm assembly  108  in position. To release the arm assembly  108 , the user may grasp the handles  208  and move the locking members  204  to disengage the stop  220  (such as shown in  FIG. 2C ). For example, in the illustrated embodiment, the user may grasp the handles  208  and slide the locking members  204  forward to engage the stop  220  and backward to disengage the stop  220 . It is noted that then handles  208  may be used for other purposes as well. For instance, a user may grasp the handles during training to further engage the arm assembly  108  as will be described further below. 
     The locking mechanism may have locking members  204  which share a common end  212  in some embodiments. For instance, as shown in  FIG. 2D , the locking members  204  are linked at a shared end  212 . The end  212  may be configured as discussed above to lock the arm assembly  108  in position. Alternatively, the end  212  may have a rotatable portion which engages a stop  220  to hold the arm assembly  108  in position. 
     One such embodiment is illustrated in  FIG. 2D . As can be seen, the end  212  may comprise a roller  224  which rolls to engage a stop  220 . In the embodiment of  FIG. 2D  the roller  224  wedges itself between the stop  220  and the arm assembly  108  as the locking members  204  are moved to lock the arm assembly in position. The roller  224  is circular in shape and may rotate about an axle. The roller  224  may optionally have one or more grooves, such as shown, to fit tightly between the arm assembly  108  and stop  220 . It is contemplated that the roller  224  may be formed from rubber, plastic, wood, metal, or other rigid or semi-rigid material in one or more embodiments. In  FIG. 2D  for example, the groove  232  in the roller  224  allows the roller to accommodate a rounded portion of the arm assembly  108  adjacent the stop  220 . 
     In one or more embodiments, the stop  220  may have a flange  236  or angled portion, such as shown in  FIG. 2D . This is beneficial in that it provides an expanded area for accepting the roller. As can be seen, the flange  236  may be angled downward and/or away from the arm assembly  108  to provide a larger distance between the arm assembly and the stop  220 . In this manner, the roller  224  may be guided “into” a tighter or smaller area between the stop  220  and the arm assembly  108  by the flange  236  to lock the roller and thus the arm assembly  108  in position. It is noted that a flange  236  need not be provided in all embodiments as the roller  224  may engage the stop  220  without the flange. In an alternate embodiment, rather than including a flange  236 , the stop  220  itself may be angled away from the arm assembly  108 . 
     The roller  224  may be disengaged from the stop  220  by moving the roller away from the stop such as shown in  FIG. 2D . As discussed above, this may be accomplished via handles of the locking members  204 . Once disengaged the arm assembly  108  may be moved to perform one or more exercises. 
     In general, the arm assembly  108  provides a resistance to the user&#39;s movements during training. This is highly beneficial in that it enhances the strengthening and toning of the user&#39;s muscles during training. The resistance may comprise a force applied to the user by the arm assembly  108 . The resistance may be directed along various force vectors. Typically, the resistance will be along a downward force vector and may be at various angles. Accordingly, this allows the arm assembly  108  to provide a resistance having a downward force vector to the user. 
     Various resistance devices may be used to generate this resistance. In fact, it is contemplated that any device configured to provide a downward force through the arm assembly  108  may be used. For example, one or more weights may be coupled or attached to the arm assembly  108  to provide the downward force, such as shown in  FIGS. 7A-7B . As can be seen a support or mount for one or more weights  708  may be used to attach the weights to a portion of the arm assembly  108 . For instance, one or more bars  704  or the like may extend from the arm assembly  108  to hold one or more weights  708 . As shown, the weights  708  are held at the engagement end  140  of the arm assembly  108 , however, it is contemplated that the weights may be at various positions along the arm assembly. It is contemplated that weights  708  may be removed and replaced as desired to provide the desired amount of resistance. 
     In another example of the alternate embodiment change of direction machine shown in  FIGS. 8 and 9 , a weight stack or weight stack assembly may be coupled with the arm assembly  108 . For example, one or more pulleys may be used to guide a cable of the weight stack to the arm assembly  108  such that a downward force is provided (e.g., the cable approaches the arm assembly from below the arm assembly). Typically, a resistance device will be connected to the arm assembly  108  at the arm assembly&#39;s cantilever  124 . In the alternate embodiment shown in  FIGS. 8 and 9 , a cable  510  is attached to one end of connector bar  502  by way of connector  511 . Cable  510  runs around pulley  509  and connects to the weight stack assembly  514 . It is contemplated that the change of direction machine shown in  FIGS. 8 and 9  may be modified to form an alternate embodiment such that free weights may be used instead of a weight stack. This can be accomplished by, for example, the use of bull horns being affixed to either or both sides of a head plate, which is then affixed to the end of cable  510 . Free weights, in multiple combinations of weight, may then be hung on (and readily removed from) either or both sides of the head plate in order to create variable resistance. 
     As can be seen from  FIG. 1A , the resistance device may comprise one or more springs  112 . As can be seen, the spring  112  may be attached between the arm assembly  108  and the support assembly  104 . A first end  132  of the spring  112  may be attached to the cantilever  124  while a second end  132  of the spring may be attached to the support assembly  104  such that the second end  132  of the spring is below the first end  132 . In this manner, the spring  112  stretches and thus provides resistance as the arm assembly  108  is moved upward. In other words, the spring  112  provides a downward force through the arm assembly  108 . It is noted that though described herein with reference to one or more springs  112 , other similar resistance devices may be used in this manner. For example, one or more elastic bands may be used instead or in addition to springs. 
     Springs  112  (or elastic bands) are beneficial in that they may be used to provide variable resistance. A spring  108  is advantageous because it may provide variable resistance in one or more embodiments. Generally, a variable resistance is one that may increase or decrease as it is moved or stretched. For example, as the spring  112  is stretched, the amount of resistance it provides may increase. In contrast, a fixed resistance, such as a weight, remains constant as it is moved. 
     A user&#39;s strength may vary along a strength curve. For example, the strength of a muscle may increase as it contracts. In addition, the body&#39;s skeletal structure contains many fulcrum and lever structures (e.g., arms, legs, and their joints) that can make a resistance more or less easy to move depending on the position of these structures. In contrast to a fixed resistance, a variable resistance, in one or more embodiments, may increase with the body&#39;s strength curve. Though this is advantageous, it will be understood that the change of direction machine may be used with fixed resistance devices, such as the weights described above. 
     The amount of resistance provided may be adjustable in one or more embodiments. Adjustment of resistance may occur in a variety of ways. For example, the user may increase the amount of weight coupled with the arm assembly in some embodiments. In other embodiments, the user may replace one or more springs  112  or elastic bands with other spring(s) or elastic band(s) to adjust resistance. Alternatively or in addition, springs  112  or elastic bands may be added to increase resistance and removed to decrease resistance. 
     In embodiments using springs  112  or the like, the change of direction machine may include elements or to adjust the resistance provided. For example, the arm assembly  108 , support assembly  104 , or both may be configured to adjust the resistance. This may occur in a variety of ways. To illustrate, the arm assembly  108 , support assembly  104 , or both may have components or structures which increase the tension on the change of direction machine&#39;s springs  112 . In this manner, the amount of resistance provided by the springs  112  is increased. Likewise, the arm assembly  108 , support assembly  104 , or both may be used to decrease such tension to correspondingly decrease the amount of resistance provided. 
     For instance, the embodiment of  FIG. 1A  illustrates an exemplary arm assembly  108  comprising a tension adjuster  144  that may be used to increase or decrease tension on one or more springs  112 . In general, the tension adjuster  144  increases tension by elongating the spring  112  and decreases tension by allowing the spring to contract. It is noted that some tension may always be on the spring  112  so that resistance is immediately provided to a user during training. 
     In one or more embodiments, a spring  112  may provide a substantial force. It is contemplated that several hundred pounds of force may be generated in some embodiments (though other amounts of force may also be generated). In these embodiments, manually adjusting the tension of the spring  112  may be difficult if not impossible. In addition, adjustment of the tension could be dangerous given the forces generated by the spring  112 . Therefore, the tension adjuster  144  may be configured to assist a user in adjusting the tension. This is highly beneficial in that it allows easy and safe adjustment of tension. In addition, in some embodiments, tension adjuster  144  may have one or more set locations or positions. This allows the user to set the resistance to a set level consistently. It is contemplated that the tension adjuster  144  may have one or more indicators (e.g., labels) associated with its set positions which indicate how much tension or force would be provided by the change of direction machine if the tension adjuster  144  were moved to a particular position. This is beneficial in that the amount of tension of force may not be readily apparent when using springs  112 , elastic bands, or the like. 
     In one or more embodiments, the tension adjuster  144  may be movable along the arm assembly  108  to allow tension adjustments of the spring  112  and may be secured in place once the desired tension is achieved. As shown in  FIGS. 3A-3D , the tension adjuster  144  may be moved from one position to another to increase or decrease the tension. In  FIGS. 3A and 3C , a first tension is provided, while in  FIGS. 3B and 3D  an increased tension is provided by moving the tension adjuster  144  to increase the tension on the spring. As can be seen, various tensions may be generated by positioning the tension adjuster  144  at various locations along the arm assembly  108 . 
     The tension adjuster  144  may have various configurations. In one or more embodiments, the tension adjuster  144  may comprise a body configured to allow the tension adjuster to move along the arm assembly  108 , such as along a track of the arm assembly, and a brake to hold the tension adjuster in position once the desired amount of tension is achieved. To assist in moving the tension adjuster  144 , the tension adjuster may comprise a ratcheting mechanism in one or more embodiments. In these embodiments, the ratcheting mechanism may also provide a braking or locking function which holds the tension adjuster  144  in position. 
     The arm assembly  108  may comprise a track  304  in one or more embodiments. The track  304  may be configured to guide the tension adjuster  144  as the tension adjuster is moved. For example, the track  304  may be an elongated structure between the pivoting end  136  and the engagement end  140  of the arm assembly  108 . In this manner, the track  304  allows the tension adjuster  144  to move along the arm assembly  108  between the pivoting end  136  and the engagement end  140 . The track  304  may be a separate structure or may be integrally formed with another component of the arm assembly  108 . For example, as shown in  FIG. 3E , the track  304  has been integrally formed with the cantilever  124  of the arm assembly  108 . 
     The track  304  may also comprise one or more features which allow the tension adjuster  144  to be moved along the track and/or be secured in position. For example, in  FIG. 3E , the track comprises a series of indentations  308  that aid in moving the tension adjuster  144  and in securing the tension adjuster in place, as will be described further below. Of course indentations  308  need not be provided in all embodiments. It is contemplated that the tension adjuster  144  may operate on a smooth track  304  in some embodiments. Alternatively, the indentations  308  may be various other structures. For example, the track  304  may comprise a series of openings. The track  304  may also or alternatively include a rough surface to increase friction between the track and the tension adjuster  144 . This allows the tension adjuster  144  to have sufficient “traction” to both elongate the springs  112  and be secured in position. 
       FIG. 3E  illustrates an embodiment of the tension adjuster  144  comprising a body  312  having a ratcheting mechanism. As can be seen, the body  312  is configured to ride along a track  304  that has been integrally formed into the cantilever  124  of the arm assembly  108 . The tension adjuster  144  may include a handle  316  that the user may use to move the tension adjuster. In one or more embodiments, the handle  316  may be coupled with the ratcheting mechanism such that actuating the handle  316  causes the tension adjuster  144  to move. 
     For example, in  FIG. 3E , the handle  316  may be actuated about a pivot  324 . This causes a gear or finger of the ratcheting mechanism to engage at least one of the indentations  308  of the track  304 . The force applied to the handle  316  may then be transferred via the gear or finger to the track  304  causing the tension adjuster  144  to move. Because the handle  316  may function as a lever, the user&#39;s force is amplified thus making it easier (and safer) to move the ratcheting mechanism and adjust the tension on the springs  112 . 
     In one or more embodiments, the handle  316  may be moved to a locking position once the tension adjuster  144  has reached the desired position. In one or more embodiments, placing the handle  316  in the locking position causes the gear or finger to be locked in position relative to the track, thus securing the tension adjuster in position. In  FIG. 3E , the handle  316  is illustrated in a locked position. As can be seen, the locked position is one where the handle  316  is pushed (or pulled) forward to engage a stop  328 . A release  320  coupled with the ratcheting mechanism may be provided to release the handle  316  from its locked position. For example, actuating the release  320  may release the handle  316  such that the handle may once again be actuated to move the tension adjuster  144 . 
     The ratcheting mechanism may be configured to move the tension adjuster  144  in one direction. For instance, the ratcheting mechanism may be configured to move the tension adjuster  144  away from the pivoting end  136  of the arm assembly  108  in one or more embodiments. The ratcheting mechanism may also be configured to move the tension adjuster in multiple directions. For instance, actuating the handle  316  towards the engagement end  140  of the arm assembly  108  may cause the tension adjuster  144  to move towards the engagement end while actuating the handle towards the pivoting end of the arm assembly causes the tension adjuster to move towards the pivoting end, or vice versa. 
     In embodiments where the ratcheting assembly is configured to move the tension adjuster  144  in one direction along a track, it is contemplated that an additional ratcheting assembly (oriented in the opposite direction) may be provided to allow movement in the opposite direction. In this manner, a first handle  316  may be actuated to move the tension adjuster  144  in one direction while a second handle may be actuated to move the tension adjuster in the opposite direction. Either or both handles may be move to their respective locked positions to secure the tension adjuster  144  in position. 
     The tension assembly  144  may move freely in one direction in some embodiments. For example, in some embodiments the tension assembly  144  may “ratchet” towards the engagement end  136  of the arm assembly  108  and be secured in position when the desired tension is achieved. If released from this position, the tension adjuster  144  may then freely move in the opposite direction towards the pivoting end  136  of the arm assembly. This is advantageous because the ratcheting assembly is used to move the tension adjuster  144  in the direction which increases tension on the springs  112 . 
     In addition to the ratcheting mechanism described above, various other mechanisms may be used to move or help move the tension adjuster  144  towards the pivoting end  136  of the arm assembly. This returns the tension adjuster  144  to a position of lowered or low tension. Such return mechanisms may provide a force which pushes or pulls the tension adjuster  144  towards the pivoting end  136 . It is contemplated that the return mechanisms may be electrically powered or motorized in one or more embodiments. For example, a gear or other drive mechanism coupled to the tension adjuster  144  may move the tension adjuster when energized or otherwise powered up. 
     Return mechanisms are beneficial in overcoming friction between the tension adjuster  144  and the track  304  or other portion of the arm assembly. For example, given the downward force applied by the spring  112 , it may be difficult to move the tension adjuster  144  toward the pivoting end  136 . The force provided by the return mechanisms thus allows the tension adjuster  144  to be easily moved or returned to a position nearer the pivoting end  136  where the force provided by the change of direction machine is lower. 
       FIGS. 3C-3D  illustrate an exemplary return mechanism that may be used to move the tension adjuster  144  towards the pivoting end  136 . As can be seen, the return mechanism may comprise one or more resilient members  304  which attach to the tension adjuster  144  via a connector  312 . The resilient members  304  may be attached to the top, bottom, or one or both sides of the tension adjuster  144 . This attachment or connection between a resilient member  304  and tension adjuster  144  allows the resilient member to apply a force to the tension adjuster which helps move or moves the tension adjuster. The resilient member  304  may be a resiliently stretchable device or material, such as a spring or elastic band. 
     In one or more embodiments, the resilient member  304  may be attached to the tension adjuster  144  through a cable  308  or other connecting structure. In the case of a cable  308 , a pulley  312  or other cable guide (e.g., a channel, hole, or conduit) may be used to guide the cable from the tension adjuster  144  to the resilient member  304 . This is beneficial where the tension adjuster  144  and resilient member  304  are at an angle to one another. As seen in  FIGS. 3C-3D  for example, the pulley  312  directs the cable  308  from the tension adjuster  144  to the resilient member  304  at an angle. 
     As shown in  FIG. 3D , as the tension adjuster  144  is moved away from the pivoting end  136  and towards the engagement end  140 , the resilient member  304  may be elongated or stretched. This in turn causes the resilient member  304  to apply a force in the opposite direction that, if not opposed, would return the tension adjuster  144  to a position nearer the pivoting end  136 , such as shown in  FIG. 3C . 
     As stated, the tension adjuster  144  may be various structures or devices which allow the amount of force provided by the change of direction machine to be adjusted. Thus, the tension adjuster  144  need not utilize a ratcheting mechanism in all embodiments. For example, the tension adjuster  144  may comprise a body configured to accept a threaded rod of the tension adjuster&#39;s track. In this manner, the tension adjuster  144  may be moved by turning the threaded rod. Because the threads of the threaded rod will typically hold the tension adjuster  144  in place, the tension adjuster need not be locked in position through additional actions or structures. Of course, the tension adjuster  144  may be locked in place by one or more clips, clamps, pins, or the like if desired. Alternatively or in addition, the threaded rod may be locked in place to lock the position of the tension adjuster  144 . It is contemplated that the threaded rod may be rotated manually or by a motor in one or more embodiments. 
     Though shown as part of an arm assembly  108 , it will be understood that the tension adjuster may be part of the support assembly  104 , or other portions of the change of direction machine. For example, the change of direction machine may comprise a tension adjuster and associated track on the support assembly  104 . In one embodiment, this tension adjuster elongates the springs by moving one end of the springs downward. 
     The engagement end  140  of the arm assembly  108  will now be described with regard to  FIG. 4A . In general, the engagement end  140  of the arm assembly  108  is configured to accept a user&#39;s shoulders during training. In one or more embodiments, the arm assembly  108  may comprise one or more pads  128  to engage the user&#39;s shoulders. The pads  128  may be attached to the arm assembly  108  at the engagement end  140  by various structures. For example, the pads  128  may be attached by a support  408 . Typically, the support  408  will have a width sufficient to hold the pads  128  apart from one another to engage a user&#39;s left and right shoulder. The pads  128  may be mounted rigidly to the support  408  or may be rotatably mounted to the support in one or more embodiments. For instance, as shown in  FIG. 4A , the pads  128  have been rigidly mounted to the support  408 . 
       FIG. 4B  illustrates an embodiment where the pads  128  have been mounted to a rotating or pivoting support. This allows the pads  128  to conform to the motion of the user&#39;s shoulders. In addition, the rotation of the pads  128  prevent the pads from pulling the user inward as the arm assembly  108  moves downward. This is especially beneficial where, such as shown, the pads  128  are shaped to curve around the user&#39;s shoulders. In addition, this feature allows the pads  128  to hold a user&#39;s shoulders and upper body in position such that potentially injury causing forward and backward motions of the upper body are prevented. In this manner, the user may raise and lower his or her upper body in a substantially vertical direction which provides training while greatly reducing the risk of injury. In addition, the rigid structure of the arm assembly  108  helps keep the user&#39;s upper body at a fixed distance from the support assembly  104  which also limits forward and backward movement of the user&#39;s upper body. 
     Rotation of the pads  128  may be achieved in a variety of ways. For example, the pads  128  may be mounted to a hinge or a pivot  404  in one or more embodiments. It is contemplated that rotation may be limited to certain directions in some embodiments. For example, if mounted to a hinge, rotation would generally be limited to one direction. Of course, the pads  128  may rotate in any direction in other embodiments. For example, a pivot  404  comprising a universal joint or a ball and socket joint may be used to allow rotation in a variety of directions. 
     The embodiment of  FIG. 4B  shows a pad  128  mounted in a rotatable fashion by a pivot  404  and a rotation limiter  412 . In general, the pivot  404  rotatably mounts the pad  128  to the support  408  while the rotation limiter  412  prevents the pad from certain movements. In the embodiment shown, the rotation limiter  412  is configured to limit lateral rotation of the pad  128 . 
     The pivot  404  shown comprises a ball  416  and a socket  420 . The ball  416  may be attached to the pad  128  while the socket  420  may be attached to the support  408 . A support member  424  may be used to attach the socket  420  to the support  408 . The support member  424  may be an elongated member, such as shown. 
     In general, the rotation limiter  412  operates by physically blocking certain movements of the pad  128 . For example, in  FIG. 4B , the rotation limiter  412  comprises bars which limit the lateral or side-to-side motion of the pad  128  by coming into contact with the support member  424  when the pad rotates laterally. In one or more embodiments, the rotation limiter  412  may loop around the support member  424  such as shown. 
     As can be seen, though lateral movement is limited, the rotation limiter  412  allows forward and backward rotation of the pad  128 . In this manner, the rotation limiter  412  may be thought of as a guide for the forward and backward rotation of the pad  128 . The bars of the rotation limiter  412  may be configured such that they do not block the forward and backward rotation of the pad  128 . For example, in the embodiment shown, the rotation limiter  412  extends upward from the pad  128  to allow the support member  424  to move up and down freely within the rotation limiter. 
     In one or more embodiments, the position of the pads  128  relative to the support  408  may be adjustable.  FIG. 4C  illustrates an embodiment where the pads  128  can be adjusted laterally. In this manner, the pads  128  may be moved closer together or farther apart as desired. This is beneficial in that it allows a variety of users to be accommodated by the pads  128 . For example, users with broader shoulders may move the pads  128  away from one another while users with narrower shoulders may move the pads towards one another. 
     Adjustment of the pads  128  may occur in various ways. In the embodiment shown for example, the pads  128  may be mounted to the support  408  with adjustable support members  424 . An adjustable support member  424  may comprise a sleeve  428  which is movable along a member of the support  408 . In  FIG. 4C , the sleeve  428  is movable along a horizontal member of the support  408 . This member is generally perpendicular to the user&#39;s shoulders and thus allows the pads  128  to be moved to engage a user&#39;s shoulders as desired. 
     It is contemplated that, once in the desired position, the pads  128  may be secured in position. For example, one or more pins  432  may be inserted into an opening of the sleeve  428  and into the horizontal member of the support  408  to secure the pad  128  in position. As shown, the pins  432  are spring loaded such that they bias towards the horizontal member. In this manner, the pins  432  may automatically insert themselves into an opening of the horizontal member once positioned over such an opening. Of course, other structures or devices may be used to secure the pad  128  in position. For example, the sleeve  428 , support member  424 , or both may be secured by one or more clips, clamps, screws, or the like. 
     It is contemplated that the engagement end  140  of the arm assembly  108  may be adjustable in one or more embodiments. For instance, as shown in  FIG. 4D , the engagement end  140  may pivot upwards or downwards, such as to accommodate various user preferences or to accommodate users of various sizes. Once moved to a desired position, the support  408  of the engagement end  140  may be locked in position for use and unlocked for subsequent readjustment. 
     A pivoting mount may be used to accomplish such pivoting. The pivoting mount may have various configurations. In  FIG. 4D  for instance, a rounded portion of the support  408  is held within a sleeve  436  which allows the support  408  to rotate within the sleeve  436 . Other structures may be used to accomplish such pivoting. For example, a hinge or the like could be used. 
     Once pivoted to a desired position, the support  408  may be held in position by one or more clips, clamps, screws, pins, or the like. To reposition the support  408 , these items may be released. It is contemplated that other holding mechanisms may be used as well. For instance,  FIG. 4D  illustrates a pivoting mount for the support  408  including a plate  444  configured to accept a pin  440  to hold the support  408  and thus the engagement end  140  in a desired position. 
     As can be seen, the plate  444  may have one or more openings  448  to accept the pin  440 . The pin  440  may be retractable, spring loaded, or otherwise removable to release the support  408  allowing the support to be positioned. The pin  440  may be reinserted into one of the openings  448  to hold the support  408  in the desired position. The openings  448  may be positioned in a circular arrangement, such as shown, to allow each of the openings to align with the pin  440  when the support  408  is pivoting. The plate  444  itself may have a curved shape or portion so as to avoid colliding with other structures when the support  408  is pivoting. 
     The plate  444  may be attached to the sleeve  436  while the pin  440  is mounted to a portion of the support  408  (or vice versa). In this manner, when the support  408  is pivoted the pin  440  and plate  444  move relative to one another. This allows the pin  440  to be aligned with various of the one or more openings  448  in the plate  444 . In this manner, the support  408  may be secured by the pin  440  at a variety of positions by inserting the pin into an aligned opening. As shown in  FIG. 4E , the pin  440  may be attached to a mount  452  so as to position (i.e. align) the pin such that it may enter the one or more openings of the plate  444 . Of course, a mount  452  is not required where the plate  444  and pin  440  can be properly positioned relative to one another without a mount. 
     In addition or instead of pivoting, the engagement end  140  may be height adjustable. For instance, the engagement end  140  may be configured such that the support  408  may be raised and lowered as desired and subsequently locked or secured in position. In addition or instead of the capability to pivot, the height adjustability allows the change of direction machine to accommodate users of varying heights. In addition, the height adjustability allows users to set the height of the support  408  according to their own preferences. 
       FIGS. 4F-4G  illustrate a height adjustment assembly. In general, the height adjustment assembly comprises elements that can hold the support  408  at various elevations. For instance, the height adjustment assembly may comprise an elevating shaft  456  or other member upon which the support  408  may be slideably mounted. In this manner, the support  408  may be raised or lowered to a desired position and then secured in place. Typically, the elevating shaft  456  will be in a substantially vertical or a vertical orientation. 
     The elevating shaft  456  may be mounted to the arm assembly at the engagement end  140 , such as shown in  FIGS. 4F-4G . The elevating shaft  456  may be attached to the arm assembly in various ways. In one embodiment, the elevating shaft  456  may be directly attached to the arm assembly. Alternatively, the elevating shaft  456  may be attached via one or more supporting structures. For example, as shown, the elevating shaft  456  is attached to the arm assembly at the engagement end  140  by a brace  460 . The elevating shaft  456  may be attached to the brace  460  at its ends in one or more embodiments. This allows a sliding mount to move along the length of the elevating shaft  456  without being encumbered by the brace  460 . As can be seen, the brace  460  may be substantially the same length as the elevating shaft  456 . The brace  460  may also provide structural reinforcement for the elevating shaft  456  which helps the elevating shaft support the weight of the support  408 . 
     The support  408  may be mounted to the elevating shaft  456  in various ways. In the embodiment shown, the support  408  is also attached to a pivoting mount to allow the support to pivot. It is noted however, that the support  408  may be directly attached to the height adjustment assembly. In such embodiments, the support  408  would be height adjustable but not pivotable. 
     A sliding mount may be provided to connect the support  408  to the elevating shaft  456  such that the support may move vertically relative to the elevating shaft. In one embodiment, the elevating shaft  456  may function as a track for the sliding mount thereby guiding as well as supporting the sliding mount. To illustrate, in  FIGS. 4F-4G , the sliding mount comprises a sleeve  464  which moves along the elevating shaft  456 . 
     It is contemplated that the elevating shaft  456 , sliding mount, or both may have features that make it easier for a user to raise and lower the support  408 . For example, the elevating shaft  456  may have indentations, protrusions, ridges, or the like on its surface that may be engaged by a gear. In this manner, turning the gear in one direction or another raises or lowers the sliding mount and support  408 . The gear may be rotated manually. For example, as shown, the sleeve  464  comprises a handle  468  that allows a user to turn a gear to raise or lower the support  408 . The handle  468  may be coupled to the gear by a drive mechanism having its own gears, linkages, or the like. It is noted that the gear may be rotated by a motor in some embodiments. 
     Once the desired height or elevation for the support  408  is achieved, the support may be held in place. For example, the gear may be locked such that further rotation is prevented. In this manner, the sleeve  464  and support  408  may be secured at a particular height. The gear may be locked in various ways. For example, a component coupled to the gear may prevent further rotation of the gear. To illustrate, the handle or drive mechanism may be held in place thus preventing the gear from rotating. 
     The support  408  may be secured in place in other ways as well. For example, in  FIGS. 4F-4G , it can be seen that a pin may be used to “clamp” or hold the sleeve  464  and support  408  in place. The pin may be mounted to the sleeve  464  in one or more embodiments. In one embodiment, the pin may be threaded and held within a threaded opening of the sleeve  464 . The pin may then be turned to cause the pin to move into the sleeve eventually contacting a portion of the elevating shaft  456 . The pin may then be tightened onto the elevating shaft  456  to hold the sleeve  464  and support  408  in place. The pin may then be loosened to release the support  408  for further height adjustment. 
     It is noted that the pin need not be threaded in all embodiments. It is contemplated that the pin may be inserted into or engage a feature of the elevating shaft  456  to hold the support  408  in position. For example, the pin may be inserted into one of a series of openings on the elevating shaft  456 . Alternatively, the pin may engage an indentation, ridge, protrusion, or other structural feature of the elevating shaft  456  to hold the support  408  in position. The support  408  may be released for further height adjustment by removing or disengaging the pin from the elevating shaft  456 . 
     Operation of the change of direction machine will now be described with regard to  FIGS. 5A-5C . To begin training, the user may “step into” the change of direction machine such that the user&#39;s shoulders engage the pads  128 . As can be seen in  FIG. 5  A, the arm assembly  108  holds the pads  128  at an elevated position. In one or more embodiments, the pads  128  may be held near or at the level of the user&#39;s shoulders. In this manner, the user need only lower his or her shoulders to engage the pads  128 . This makes it easier for the user to engage the pads  128  because the user does not have to stoop or bend over an excessive amount. In addition, the user does not have to lift the arm assembly  108  to place the arm assembly on his or her shoulders. This is highly beneficial especially where there is a resistance from the arm assembly  108  that would have to be lifted onto the user&#39;s shoulders. 
     Alternatively, it is contemplated that the user need not lower his or her shoulders to engage the change of direction machine. For example, the user may “step into” the change of direction machine and then lower the arm assembly  108  onto his or her shoulders, such as by unlocking the arm assembly to allow the arm assembly to move downward onto the user&#39;s shoulders. 
     In  FIGS. 5B and 10A , the user has “stepped into” the change of direction machine and engaged the arm assembly  108 . Such engagement may be achieved by the user engaging one or more pads  128  of the arm assembly  108  by raising his or her shoulders. For example, the user may stand up to engage the one or more pads  128  as shown. As can be seen, the user may cause the arm assembly  108  to lift at least slightly in this position. Also, in this position, the arm assembly  108  elongates the springs  112  (or engages the weight stack assembly  514 ), and thus resistance is applied to the user via the arm assembly and pads  128 . In this manner, resistance is immediately applied to the user and the user continues to experience the resistance during training. 
     Once the arm assembly  108  is engaged, the user may unlock the arm assembly  108  to allow the arm assembly to move freely. Of course, unlocking is not required where the arm assembly  108  is not locked or does not include a locking mechanism. The arm assembly  108  may be unlocked by disengaging the coupler of a locking mechanism as described above. For example, referring to  FIGS. 2A-2B , the user may pull or otherwise move a locking member  204  away from its stop  220  to unlock the arm assembly  108 , allowing the assembly to move freely. If handles  208  are provided, the user may move the locking member  204  through the handles. 
     In the alternative embodiment change of direction machine shown in  FIGS. 8 and 9 , the user may adjust the height of arm assembly  108  by engaging handle  506 , in the manner described in greater detail above. 
     It is noted that the stop  220 , as shown in the devices illustrated in  FIG. 5B , may comprise an open top portion. This allows the arm assembly  108  to move upwards even when locked. Thus, as shown in  FIG. 5B , when the user stands upright to engage the pads  128 , the arm assembly  108  may move upward even though it is locked. This allows the user to engage the arm assembly  108 , stand upright, and prepare for training prior to unlocking the arm assembly. 
     The user may then perform one or more exercises. For example, the user may perform one or more squats or one or more enhanced squats, as will be described further below. In addition, it is contemplated that the user may perform one or more other exercises. For example, the user may perform calf extensions such as raising the heel end of one or both of the user&#39;s feet. In the alternate embodiment change of direction machine shown in  FIGS. 8 and 9 , weight stack  511  is connected to the connector bar  502  with cable  510  and provides resistance to movement. A calf block  512  is included, which can be raised when not in use (counterweights  513  can optionally be included to assist the user in raising or lowering the calf block  512 ). In use, the user can stand on calf block  512 , as shown in  FIG. 12 . The user can then perform calf extensions by raising the heel of one or both of the user&#39;s feet. 
     To perform a squat, the user may start from an upright or standing position, such as shown in  FIG. 5B  (and in  FIG. 13A  of the alternative embodiment device). The user may then lower his or her body by bending at the knees and waist such as shown in  FIG. 5C  (and in  FIG. 13B  of the alternate embodiment device). As can be seen, the resistance provided by the arm assembly  108  applies a downward force on the user through the user&#39;s shoulders. Thus, when lowering his or her body, the user must also resist the force of the arm assembly  108 . This helps strengthen and tone the user&#39;s muscles, in particular, the user&#39;s leg muscles and gluteal muscles. In addition, other surrounding body structures (e.g., bones, tendons, and ligaments) or body structures associated with this lowering of the user&#39;s body are strengthened and toned. 
     To complete the squat, the user may then raise his or her body back to an upright position, such as that shown in  FIG. 5B  and  FIG. 13A . In moving upward to an upright position, the user must overcome the resistance applied by the arm assembly  108  through his or her shoulders. In this manner, the resistance enhances the training of the user&#39;s muscles during the upward motion. The upward motion strengthens and tones the user&#39;s muscles and body structures as described above. 
     As can be seen, the user need not grasp the arm assembly  108  during training. This is because the one or more pads  128 , pivot  120 , and downward force of the arm assembly  108  keep the arm assembly engaged to the user&#39;s shoulders, even if the user tilts his or her shoulders. This is beneficial because it frees the users hands for other purposes. For example, the user may utilize his or her arms and hands to stabilize his or her torso during training, such as by placing his or her hands at or near his or her waist. Of course, the user may grasp one or more handles of the arm assembly during training, if provided, and if desired, such as described above. 
     In contrast to weights which need to be held in the user&#39;s hands or balanced across the user&#39;s shoulders (e.g., across the user&#39;s trapezius muscle of the user&#39;s back), the arm assembly  108  remains engaged to the user without the use of the user&#39;s hands or the need for balancing. This is highly advantageous over weights in that it reduces the risk of injury, accidents, and the like. With weights the user must support and balance while lifting and lowering his or her body. This becomes increasingly difficult and increasingly dangerous as the user becomes fatigued from training, especially where the weights are substantial. In addition, with the change of direction machine, the user does not have to exert energy to hold or balance a weight. In this manner, the user&#39;s energy is focused on the desired training and not on holding or balancing weights. 
     Moreover, the arm assembly  108  provides a rigid structure which allows up and down motion and lateral motion during training, while keeping the user&#39;s upper body from moving forward or backward. For instance, arm assembly  108  and the pads  128  (or other portion of the engagement end  140 ) may “lock” a user&#39;s upper body in position such that the upper body does not move or rotate forward or backward. This prevents the user from becoming injured due to such motion in contrast to traditional squats where the weights and user&#39;s upper body are free to move forward or backward at the risk of injury. 
     It is contemplated that the arm assembly  108  may be blocked from moving below a certain point. Thus, if the user is unable to hold the arm assembly  108  the user may lower his or her shoulders/body downward to the lowest point of the arm assembly&#39;s range of motion. The weight of the arm assembly is then held by the change of direction machine&#39;s structure and the user may safely disengage the arm assembly. This is highly beneficial in that it reduces the risk of injury. With weights, the user would likely drop the weights potentially injuring him or herself and/or nearby bystanders. In fact, even if the user were to collapse the arm assembly  108  would not fall onto the user and potentially cause impact injuries. 
     One or more cross bars or other members attached to the support assembly may be provided to prevent the arm assembly&#39;s  108  from moving below a certain point. In one embodiment, a safety bar may be extend through an interior portion of the spring. As the arm assembly  108  moves downward it may contact the safety bar preventing further downward motion. 
     As stated, the arm assembly  108  has a wide range of motions which allows a variety of training to be performed with the change of direction machine. As shown in the overhead view of  FIGS. 6A through 6C  (and in  FIGS. 15A through 15C  of the alternate embodiment device), the arm assembly  108  may move in a horizontal direction instead of or in addition to the vertical motion illustrated in  FIGS. 5A-5C  and  13 A- 13 B. It is contemplated that the user may exercise by moving laterally while engaged to the arm assembly  108 . As can be seen from  FIGS. 6A-6C  and  15 A- 15 C, the resistance from the arm assembly  108  continues to be applied to the user even as the arm assembly moves laterally. Thus, it is contemplated that the user may tone and strengthen his or her lower body and torso muscles simply by stepping or otherwise moving laterally while engaged to the arm assembly  108 . This is because the user must support the resistance of the arm assembly  108  while moving. 
     One or more enhanced squats may be performed on the change of direction machine. In one or more embodiments, an enhanced squat may comprise a vertical motion and a horizontal motion performed by the user&#39;s body. For example, the user may lower and raise his or her body while moving in a lateral direction to perform an enhanced squat, as shown in  FIG. 11 , which depicts such movement using the alternate embodiment change of direction machine shown in  FIGS. 8 and 9 . This combined motion is highly beneficial because it strengthens and tones muscles and other body structures used in changing the direction of a user&#39;s body. For athletes and other users, the ability to quickly and powerfully stop and/or change the direction of one&#39;s body is highly advantageous. For instance, a tennis player may need to quickly move in one direction for a return and move in another direction for another return. In basketball, a player may need to quickly change directions to avoid or split defenses as well as to prevent quick players from scoring. 
     Of course, any user may benefit from such training. The muscles and body structures used to change directions (e.g. the muscles and structures along the sides of the user&#39;s body and the interior of the user&#39;s legs) are difficult to train. Traditional exercise devices lack a pivoting arm assembly  108  or the equivalent to allow this type of training. Use of free weights in this manner is exceedingly dangerous and requires the user to exert energy to hold and/or balance the weights. The change of direction machine allows exercises involving changes of direction and enhances the effectiveness of these exercises by applying a resistance to the user. 
     The pivoting arm assembly  108  provides a wide range of motion while the user is engaged to the arm assembly as can be seen from  FIGS. 6A-6C  and  15 A- 15 C. This allows the user to move in a wide area around the change of direction machine while experiencing the resistance provided by the machine. This also allows training to be enhanced by the resistance applied to the user through the arm assembly  108 . Thus, the user achieves results a great deal faster with the change of direction machine. 
     In fact, the user is able to achieve results that would otherwise be impossible. This is because the resistance provided by the arm assembly  108  is applied to the user across a wide range of movements around the change of direction machine. In other words, the change of direction machine and its pivoting arm assembly  108  provides a combination of resistance and range of motion that a user could not otherwise experience. In addition, as stated above, the resistance provided by the arm assembly  108  may be increased to a substantial amount, further enhancing the user&#39;s training with the change of direction machine. 
     An enhanced squat will now be described with regard to  FIGS. 5A-5C  and  FIGS. 6A-6C , and  FIGS. 13A-13B  and  FIGS. 15A-15C . The user may “step into” the change of direction machine as shown in  FIG. 5A  and engage the arm assembly  108  as shown in  FIG. 5B . In one embodiment, the arm assembly  108  may be perpendicular to the support assembly  104  as this is occurring, such as shown in  FIG. 6A . Of course, the arm assembly  108  may be at various angles. And, as already described in greater detail above, the user of the alternate embodiment device shown in  FIGS. 8 and 9  may engage handle  506  to easily and readily adjust the height of arm assembly  108 , after stepping into the alternate embodiment device, as shown in  FIG. 13A . 
     Typically, the arm assembly  108  will be locked in position. Thus, the user may unlock the arm assembly  108  if applicable prior to training. As stated, this may occur by disengaging a coupler of an arm assembly&#39;s locking mechanism. Once unlocked, the arm assembly  108  may move freely in a vertical direction as well as in a horizontal direction. 
     To begin an enhanced squat, the user may step laterally with one leg. The user may simultaneously lower his or her upper body by bending at the knees and hips, such as shown in  FIG. 5C  and  FIG. 13B . For example, the user may take a rightward step with his or her right leg and lower his or her upper body to a squatting position. As the user lowers his or her body, the arm assembly  108  is moved downward, as shown in  FIG. 5C  (and in  FIG. 11  with respect to the alternate embodiment device), and rightward as shown in  FIG. 6C  (and in  FIGS. 11 and 15B ). While in this “rightward” location, the user may then raise his or her body and the arm assembly, such as shown in  FIG. 5B  and  FIG. 13A . The user may then move one leg towards his or her other leg to complete the lateral motion. In the above example, the user may move his or her left leg towards his or her right leg such that the user&#39;s feet are approximately shoulder width apart. 
     As can be seen the structure of the arm assembly  108  holds the user&#39;s upper body in position so that the upper body has limited forward and backward movement. As discussed, this greatly reduces the risk of injury when training, especially as compared to traditional apparatus and methods. The arm assembly&#39;s structure may position the user&#39;s upper body at a fixed distance away from the support structure  104 . Thus, even though the user may raise and lower his or her upper body, move laterally, or do both, the user&#39;s upper body motion in a forward-backward direction is limited thereby increasing the user&#39;s safety. 
     The user may then perform one or more squats or one or more additional enhanced squats. For example, the user may continue moving leftward as indicated by the arrow of  FIG. 6B , or the user may move rightward if additional enhanced squats are desired. The user may also stay in the same location and perform squats. If the user desires to move leftward, he or she may repeat the motions described above. It is contemplated that the user may continue moving in one direction until the arm assembly  108  is parallel to the support assembly  104  (or beyond) in one or more embodiments. This allows motions in the same direction to be repeated several times before the user must move in another direction, which is advantageous to strengthening and toning the user&#39;s body for these motions. 
     To move rightward, the user may begin from a position where his or her feet are adjacent, such as a shoulder&#39;s width apart and step with his or her right foot in a rightward direction while lowering his or her upper body, such as shown in  FIG. 5C  and  FIG. 13B . This causes the arm assembly  108  to move rightward. For example, if the user is located at the position shown in  FIG. 6B  (or  FIG. 15C  in the alternate embodiment device), moving rightward may cause the arm assembly  108  to be moved back to the position in  FIG. 6A  or  15 A. The user may then raise his or her upper body to the position shown in  FIG. 5B  and  FIG. 10A . The user may continue moving rightward to the location shown in  FIG. 6C  (and  FIGS. 11 and 15B ), may stay in the same location, or may change direction and move leftward such as to the location shown in  FIG. 6B  or  FIG. 15C . This may be repeated as desired. 
     It can thus be seen that the user may rapidly alternate between rightward and leftward motions to train the muscles and body structures involved in changing direction. Likewise, the user may also perform one or more repetitions in one direction and then alternate to another direction to train these muscles and body structures. 
     It is contemplated that the arm assembly  108  may be configured to rotate 360 degrees around the support assembly  104  in one or more embodiments. For example the resistance device, such as a spring or elastic band, may be mounted to a rotating mount on the support assembly  104 . In this manner, the arm assembly  108  may be permitted to rotate 360 degrees around the support assembly  104  while continuing to provide resistance to the user. The user may then perform as many enhanced squats in a leftward or rightward direction as the user desires. The user also may engage in bounding or jumping exercises, as shown in  FIGS. 14A and 14B , for example. 
     In addition to the leg muscles and gluteal muscles trained by squat-type exercises, the change of direction machine focuses training on specific muscles used in performing changes of direction. For example, muscles and body structures of the left and right sides of the user may be toned and strengthened. For instance, the inner and outer thigh muscles may be toned and strengthened as well as the user&#39;s side abdominal muscles. This is highly beneficial in that these muscles and associated body structures are typically difficult to tone and strengthen. In addition, the user&#39;s torso or core muscles and body structures may also be toned and strengthened in support the resistance of the arm assembly  108  while moving in a lateral direction. 
     While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. In addition, the various features, elements, and embodiments described herein may be claimed or combined in any combination or arrangement.