Abstract:
An exercise apparatus includes a frame, a footpad for supporting a user&#39;s foot, and a sensor that generates a force indicating signal indicative of a force applied to the footpad in a horizontal direction by the user&#39;s foot. A mechanism couples the footpad to the frame and guides the footpad in a closed path having at least first and second mutually perpendicular dimensions in response to forces applied to the footpad by the user&#39;s foot, the first dimension being parallel to said horizontal direction. The mechanism resists movement of the footpad in the horizontal direction in response to an electrical control signal supplied as input to the mechanism. A control system receives the force indicating signal and generates the control signal such that the mechanism resists movement depending on the force indicated by the force indicating signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This is a continuation-in-part of U.S. patent application Ser. No. 09/684,667, filed on Oct. 6, 2000. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to exercise methods and apparatus, including relationships between arm supporting members and leg supporting members on various types of exercise equipment, and/or switching between different phases of exercise performed on exercise equipment. 
       BACKGROUND OF THE INVENTION 
       [0003]    Exercise equipment has been designed to facilitate various exercise motions, many of which incorporate both arm movements and leg movements. Examples of such equipment include elliptical exercise machines (U.S. Pat. Nos. 5,242,343, 5,423,729, 5,540,637, 5,725,457, and 5,792,026); free form exercise machines (U.S. Pat. Nos. 5,290,211 and 5,401,226); rider exercise machines (U.S. Pat. Nos. 2,603,486, 5,695,434, and 5,997,446); glider/strider exercise machines (U.S. Pat. Nos. 4,940,233 and 5,795,268); stepper exercise machines (U.S. Pat. No. 4,934,690); bicycle exercise machines (U.S. Pat. Nos. 4,188,030 and 4,509,742); recumbent cycling machines (U.S. Pat. No. 5,938,570); and other miscellaneous exercise machines (U.S. Pat. Nos. 4,869,494 and 5,039,088). These patents are incorporated herein by reference as examples of suitable applications for the present invention. 
         [0004]    Generally speaking, the foregoing exercise machines have arm supporting members and leg supporting members which are typically synchronized to facilitate a coordinated “total body” exercise motion. The synchronized motion is considered advantageous to the extent that it makes the equipment relatively easy to use. On the other hand, the perceived quality of exercise tends to exceed the actual quality of exercise because the arms typically perform very little work. In other words, the arms may be described generally as “along for the ride.” 
         [0005]    In contrast to the foregoing machines, other exercise machines have been developed to provide independent upper body exercise and lower body exercise. One notable example is the NordicTrack ski machine (U.S. Pat. No. 4,728,102). On machines of this type, both the perceived quality of exercise and the actual quality of exercise are relatively greater. The trade-off is that many people consider such machines difficult to use, due to the independent nature of the arm motions and the leg motions. Recognizing that each of the foregoing types of total body exercise machines suffers certain shortcomings, room for improvement remains with respect to total body exercise machines. 
         [0006]    All of the foregoing exercise machines are used primarily for purposes of aerobic exercise. Various other sorts of equipment are provided to facilitate anaerobic or strength exercise. In other words, a need also exists for exercise equipment that facilitates both aerobic and anaerobic exercise, and/or encourages users to switch between these two types of exercise. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides unique methods and apparatus for facilitating total body exercise, displaying data associated with total body exercise, and/or switching between aerobic and anaerobic exercise. 
         [0008]    In one sense, the present invention may be described as encouraging one or more arm supporting members to be synchronized relative to respective leg supporting member(s) while allowing relative movement between the arm supporting members and respective leg supporting members in response to the application of force by a user. The present invention may also be said to encourage one or more arm supporting members to be synchronized relative to respective leg supporting member(s) while subjecting the arm supporting members to resistance which is applied and/or measured independent of the leg supporting members. The present invention may also be said to encourage a person to switch between two different modes of exercise involving arm supporting members and/or leg supporting members. 
         [0009]    Various aspects of the present invention may be described with reference to an exercise machine having a frame, left and right leg supporting members, and left and right arm supporting members. Each leg supporting member is part of a linkage assembly designed to accommodate foot motion through a generally elliptical path, and each arm supporting member is pivotally connected to the frame and/or a respective leg supporting member to accommodate hand motion through a generally reciprocal path. A separate resilient member may be interconnected between each arm supporting member and either the frame or a respective leg supporting member to bias the arm supporting member to move through a particular path in response to movement the respective leg supporting member. In such cases, each arm supporting member remains synchronized with a respective leg supporting member in the absence of user force applied against the arm supporting member. 
         [0010]    This same exercise machine preferably includes a resistance device to provide adjustable resistance to movement of the leg supporting members and the arm supporting members, and sensors for detecting user force exerted against respective arm supporting members. In one desired mode of operation, resistance to movement of the leg supporting members is set, and the resistance is subsequently adjusted in response to measurements of user force applied against the arm supporting members. As a result, upper body work can increase or decrease without affecting the amount of lower body work being performed by the user. 
         [0011]    Alternative embodiments of the present invention may be implemented with this “responsive resistance” arrangement to the exclusion of the resilient members discussed in the preceding paragraph, or with the resilient members to the exclusion of the “responsive resistance” arrangement. Different embodiments of the present invention may also be implemented with different numbers and types of leg supporting members and/or arm supporting members. 
         [0012]    The present invention may also be described in terms of distinguishing between work performed by a user&#39;s arms and work performed by a user&#39;s legs. For example, a controller may periodically sense the force exerted by a user&#39;s arms and display the amount of upper body work being performed, either alone or in comparison to lower body work and/or target levels of work. The amount of lower body work may be determined by calculating the total amount of work (based on the resistance setting and speed of exercise) and subtracting the amount of upper body work (based on forces measured at the arm supporting members). The same controller may also adjust the leg resistance device based upon the work being performed by the user&#39;s arms (as discussed above) and/or the total work being performed (for example). 
         [0013]    The present invention may also be described in terms of distinguishing between one or more modes of aerobic or cardio exercise, and one or more modes of anaerobic or strength exercise. For example, a controller may periodically switch between modes of exercise and display data associated with the current mode. The switch in modes may involve a change in resistance to encourage a different type of exercise (e.g. relatively less resistance in the cardio mode, and relatively greater resistance in the strength mode), or a change in the amount or percentage of force exerted by a person&#39;s upper body (e.g. less arm work in the cardio mode, and relatively greater arm work in the strength mode). 
         [0014]    Certain embodiments and applications of the present invention are described in greater detail below and/or shown in the accompanying figures. However, the present invention is not limited to these particular embodiments and/or applications, nor even to the types of machines on which they are shown. Moreover, the present invention is applicable to different combinations of force receiving and/or limb moving members, and may be implemented in different ways on different machines. Additional variations and/or advantages will become more apparent from the detailed description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0015]    With reference to the Figures of the Drawing, wherein like numerals represent like parts and assemblies throughout the several views, 
           [0016]      FIG. 1  is a side view of an exercise apparatus constructed according to the principles of the present invention; 
           [0017]      FIG. 2  is an enlarged perspective view of a portion of the exercise apparatus of  FIG. 1 ; 
           [0018]      FIG. 3  is a plan view of a user interface on the exercise apparatus of  FIG. 1 ; 
           [0019]      FIG. 4   a  is a flow chart of a control program suitable for use in conjunction with the exercise apparatus of  FIG. 1 ; 
           [0020]      FIG. 4   b  is a flow chart of another control program suitable for use in conjunction with the exercise apparatus of  FIG. 1 ; 
           [0021]      FIG. 5  is a plan view of an alternative user interface display; 
           [0022]      FIG. 6  is a plan view of another alternative user interface display; 
           [0023]      FIG. 7  is a perspective view of another exercise apparatus constructed according to the principles of the present invention; 
           [0024]      FIG. 8  is a side view of yet another exercise apparatus constructed according to the principles of the present invention; 
           [0025]      FIG. 9  is a plan view of a fourth user interface suitable for use on the exercise apparatus of  FIG. 1  (or any other appropriate exercise apparatus); 
           [0026]      FIG. 10  is a plan view of a fifth user interface suitable for use on the exercise apparatus of  FIG. 1  (or any other appropriate exercise apparatus); 
           [0027]      FIG. 11  is a plan view of a sixth user interface suitable for use on the exercise apparatus of  FIG. 1  (or any other appropriate exercise apparatus); 
           [0028]      FIG. 12  is a plan view of a seventh user interface suitable for use on the exercise apparatus of  FIG. 1  (or any other appropriate exercise apparatus); 
           [0029]      FIG. 13  is a plan view of a eighth user interface suitable for use on the exercise apparatus of  FIG. 1  (or any other appropriate exercise apparatus); 
           [0030]      FIG. 14  is a plan view of a ninth user interface suitable for use on the exercise apparatus of  FIG. 1  (or any other appropriate exercise apparatus); 
           [0031]      FIG. 15  is a plan view of a tenth user interface suitable for use on the exercise apparatus of  FIG. 1  (or any other appropriate exercise apparatus); and 
           [0032]      FIG. 16  is a plan view of the user interface of  FIG. 15  with an alternative display shown on the interface screen. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0033]    An exercise apparatus constructed according to the principles of the present invention is designated as  100  in  FIGS. 1-2 . The exercise apparatus  100  is an elliptical motion exercise machine that is similar in many respects to certain exercise machines disclosed in U.S. Pat. No. 5,895,339 (which is incorporated herein by reference). However, the various aspects of the present invention are not limited to this specific type of exercise machine nor to any particular category of exercise machines, but rather, are suitable for use on various sorts of exercise equipment. Examples of some other suitable applications for the present invention are disclosed in the prior art patents identified above in the Background of the Invention. 
         [0034]    The exercise apparatus  100  is generally symmetrical about a vertical plane extending lengthwise through its center. Generally speaking, the apparatus  100  includes similar “right-hand” linkage components and “left-hand” linkage components which are disposed on opposite sides of the plane of symmetry, and which are one hundred and eighty degrees out of phase relative to one another. Like reference numerals are used to designate both the “right-hand” and “left-hand” parts, and when reference is made to one or more parts on one side of an apparatus, it is to be understood that corresponding part(s) are disposed on the opposite side of the apparatus. Certain components, which are intersected by the plane of symmetry and/or are associated with the inertial characteristics of the linkage assembly, exist individually and thus, do not have any “opposite side” counterparts. 
         [0035]    The exercise apparatus  100  includes a frame  110  which extends from a forward end to a rearward end and has an I-shaped base configured to rest upon a floor surface. A forward stanchion extends upward from the base at the forward end of the frame  110 , and a rearward stanchion extends upward from the base at the rearward end of the frame  110 . Also, a trunnion extends upward from the base at an intermediate portion of the frame  110 . The linkage assembly is movably interconnected between the rearward stanchion, the forward stanchion, and the intermediate trunnion. Generally speaking, the linkage assembly links rotation of left and right cranks  120  to generally elliptical motion of left and right foot supports  155 . The term “generally elliptical motion” is intended in a broad sense to describe a closed path of motion having a relatively longer first axis and a relatively shorter second axis (which extends perpendicular to the first axis). 
         [0036]    On each side of the apparatus  100 , a respective crank  120  is rotatably mounted on the rear stanchion via a common crank shaft. The depicted crank  120  is a disc which also functions as a pulley (or sprocket), but the invention is not limited to this particular arrangement. A flywheel  124  is rotatably mounted on the rear stanchion, beneath the crank disc  120 , and is connected in “stepped-up” fashion to the crank disc  120 . In particular, a relatively smaller diameter pulley (or sprocket) is rigidly secured to the flywheel  124  and linked to the crank disc  120  by means of a looped linkage member  122 , such as a timing belt (or chain). An eddy current resistance device  126  is mounted on the frame  110  and operatively connected to the flywheel  124 . The components described in this paragraph, as well as their arrangement and operation, are well known in the art. Generally speaking, the flywheel  124  adds inertia to the linkage assembly, and the eddy current resistance device  126  provides adjustable resistance to rotation of the flywheel  124  (and associated movement of the components of the linkage assembly). 
         [0037]    A radially displaced portion of each crank  120  is rotatably connected to an intermediate portion of a respective connector link  130  at a respective connection point  132 . The lower end of each connector link  130  is rotatably connected to a rearward end of a respective rocker link  140  at a respective connection point  134 . An opposite, forward end of each rocker link  140  is pivotally connected to the intermediate trunnion at a respective connection point  141 . An opposite, upper end of each connector link  130  is rotatably connected to a rearward end of a respective foot supporting link  150  at a respective connection point  135 . An opposite, forward end of each foot supporting link  150  is rotatably connected to a lower end of a respective rocker link  160  at a respective connection point  156 . An intermediate portion of each foot supporting link  150  is sized and configured to function as a respective foot support  155 . An opposite, upper end of each rocker link  160  is rotatably connected to the forward stanchion at pivot axis P (shown in  FIG. 2 ). 
         [0038]    On each side of the apparatus  100 , a hub  166  is rigidly secured to the upper end of a respective rocker link  160  and has a star-shaped or keyed perimeter which projects axially, in a direction away from the central plane of symmetry. A generally annular member  186  has a central, star-shaped opening or keyway which fits snugly about a respective hub  166 , thereby keying the two members  186  and  166  to one another. For reasons that become more apparent below, the member  186  is resilient and preferably made of rubber. The resilient member  186  has a star-shaped or keyed perimeter which is similar in shape but larger in size than the perimeter of the hub  166 . A plate  176  has a central, star-shaped opening or keyway which fits snugly about a respective resilient member  186 , thereby keying the two members  186  and  176  to one another. A handlebar  170  has a lower end which is rigidly connected to a respective plate  176 , and an opposite, upper end  177  which is sized and configured for grasping in a respective hand of a user standing on the foot supports  155 . 
         [0039]    On each side of the apparatus  100 , two pegs  168  are rigidly secured to a respective hub  166 , project axially outward from the hub  166 , and define a gap therebetween. A metal strip  178  has an upper end which is disposed in the gap between a respective pair of pegs  168 , and an opposite, lower end which is rigidly secured to a respective plate  176  by suitable means (such as screws and/or welding). A separate strain gauge  188  (or other suitable sensor) is mounted lengthwise on each strip  178 , and is connected to a respective wire  189  which extends into the frame  110  via a centrally located bore in a centrally located bar  116 . Covers  180 , sized and configured to span the exposed side of the plates  176  (and the components within the perimeter of the plates  176 ), are preferably secured (by bolts, for example) to respective hubs  166  to shroud the components and/or prevent relative axial movement between respective plates  176 , annular members  186 , and hubs  166 . 
         [0040]    The strain gauge  188  operates in a manner known in the art to generate an electrical signal which is indicative of strain experienced by the strip  178 . An alternative type of suitable sensor may simply measure displacement, for example. Those skilled in the art will also recognize that similar sensor arrangements (and/or flexing arrangements) may be placed on other suitable portions of the apparatus  100  to measure work and/or provide tactile feedback in response to the application of arm force. 
         [0041]    Generally speaking, the arrangement inside each cover  180  biases a respective handlebar  170  to remain in a particular orientation relative to a respective rocker link  160 . As a result, each handlebar  170  will simply pivot together with a respective rocker link  160  (entirely “in sync”) when a user of the apparatus  100  is exercising his lower body to the exclusion of his upper body. However, when the user applies force through either handlebar  170 , the respective resilient member  186  will accommodate some pivoting or “flexing” of the handlebar  170  relative to the respective rocker link  160 . The freedom to move the handlebar  170  out of sync, although limited in range, tends to provide the user with the sensation of having accomplished something with his upper body independent of the motion associated with exercise of his lower body. In other words, the user can increase the arm exercise stroke relative to the leg exercise stroke, simply by pulling and/or pushing on respective handles  177 , preferably in a manner which remains coordinated with movement of the rocker links  160 . Generally speaking, the length of the arm exercise stroke is a function of force exerted by the user against the handles  177  (under a given set of operating parameters). On the preferred embodiment  100 , the dampening effect of the rubber members  186  tends to limit the rate of change in the length of the arm exercise stroke. Also, if desired, the available range of relative motion may be strictly limited by placing overlapping stops on the handlebars  170  and either the rocker links  160  or the frame  110 . 
         [0042]    Movement of a handlebar  170  relative to a respective rocker link  160  places strain on a respective strip  178 . The magnitude of the strain (and/or the displacement experienced by the strip  178 ) may be used to assess the amount of work performed via the user&#39;s upper body and/or the relative amounts of work performed via the user&#39;s upper body and the user&#39;s lower body. This information may be displayed in various forms to the user and/or used in connection with various functions of the apparatus  100 . For example,  FIG. 4   a  shows a flow chart of a program  220  suitable for controlling the resistance device  126  during variable operation of the handlebars  170 . The program  220  is described as “Auto Mode” because it is designed to automatically adjust the resistance device  126  as a function of force applied against the handlebars  170 . 
         [0043]    As an initial step  221 , the program  220  activates in response to a signal to enter the Auto Mode. The next step  222  is to set the base resistance (BR) for resisting exercise of the lower body only. For example, the base resistance may be set manually by the user, or as part of a pre-programmed exercise routine, or based upon steady state operation of the apparatus  100  over the course of a particular time period. The next step  223  is to set the current resistance (CR) for the resistance device  126  to equal the base resistance (BR). The next step  224  is to process incoming data, if any, from the sensors  188 . If no upper body force (UBF) is detected, then the program  220  returns to the step  223  of setting the current resistance (CR) equal to the base resistance (BR). On the other hand, if upper body force (UBF) is detected, then the next step  225  is to increase the current resistance (CR) to provide a reactionary force to the upper body force (UBF). The program  220  then repeats the data processing step  224 , which may involve taking multiple samples and/or performing mathematical analysis on the incoming data. 
         [0044]      FIG. 4   b  shows a flow chart of a program  230  suitable for signalling the user during variable operation of the handlebars  170 . The program  230  is described as “Prompt Mode” because it prompts the user to distribute work between the upper body and lower body in accordance with a predetermined target distribution. 
         [0045]    As an initial step  231 , the program  230  activates in response to a signal to enter the Prompt Mode. The next step  232  is to set the base resistance (BR) and the upper body target (UBT) as a percentage of the base resistance. For example, the base resistance may be set manually by the user, or as part of a pre-programmed exercise routine, or based upon a heart rate portion of the control program, and the upper body target may be set manually by the user and/or established by another portion of the control program. The next steps  233 - 238  involve the gathering and processing of data from the sensors  188 . If step  234  determines that upper body force (UBF) exceeds the upper body target (UBT) by more than 5%, then the next step  235  signals the user to use more legs and/or less arms, and then the sampling step  233  is repeated. Otherwise, step  236  determines whether or not the detected upper body target (UBT) exceeds the upper body force (UBF) by more than 5%. If yes, then step  237  signals the user to use more arms and/or less legs, and then the sampling step  233  is repeated. If no, then step  238  signals the user that the actual distribution of work is comparable to the target distribution of work, and then the sampling step  233  is repeated. The program may be further refined to distinguish between the user&#39;s left and right arms and/or the user&#39;s left and right legs, and/or to compare total actual exertion to a total target level of exertion. 
         [0046]    A user interface  190  is mounted on top of the forward stanchion on the machine  100 . Various programs, including the programs  220  and  230 , are stored within the memory of the interface  190 , and both the strain gauges  188  and the eddy current resistance device  126  are placed in communication with a controller in the user interface  190  (via wires or other suitable means). As suggested in  FIG. 3 , the user interface  190  may be configured to perform a variety of functions, including displaying information to the user, such as (a) available exercise parameters and/or programs, (b) the current parameters and/or currently selected program (see windows  197  and  198 ), (c) the current time, (d) the elapsed exercise time (see window  194 ), (e) the current and/or average speed of exercise (see window  195 ), (f) the amount of work performed during exercise, (g) the simulated distance traveled during the current workout session and/or over the course of multiple workout sessions (see window  196 ), (h) material transmitted over the internet, and/or (i) discrete amounts of work being performed by the user&#39;s arms and/or legs. 
         [0047]    With respect to information based upon multiple workout sessions, the interface  190  may be programmed to store cumulative data and also, to distinguish between multiple users of the apparatus  100 . With regard to the distribution of work, bar graphs  191   a  and  191   b  show the relative amounts of work currently being performed by a user&#39;s upper body and lower body, respectively; bar graphs  192   a  and  192   b  show the relative amounts of work performed over the course of a workout by a user&#39;s upper body and lower body, respectively; and bar graphs  193   a  and  193   b  show the relative amounts of work performed over the course of multiple workouts by a user&#39;s upper body and lower body, respectively. 
         [0048]    The user interface  190  may also be configured to perform functions allowing the user to (a) select or change the information being viewed, (b) select or change an exercise program, (c) adjust the resistance to exercise of the arms and/or the legs, (d) adjust the stroke length of the arms and/or the legs (if available), (e) adjust the orientation of the exercise motion (if available), and/or (f) quickly stop the exercise motion of the arms and/or the legs (if available). To facilitate the selection of such options, the user interface  190  includes user operable input devices  199  which may be used at various times and/or in various combinations to achieve a desired result. The devices  199  may be push buttons or sensors integrated into a display, and they may be labeled according to their functions. 
         [0049]    Those skilled in the art will recognize that various functions of the apparatus  100  may be controlled by and/or performed in response to various types of signals, including (a) the user activating an input device  199  on the user interface  190  or on either handle  177 ; (b) a sensor detecting the presence or absence of the user&#39;s hands on the handles  177 ; (c) a sensor detecting the user&#39;s level of exertion (user exerted force and/or heart rate, for example) for comparison to a target level or range; (d) an automated program; and/or (e) a person other than the user (such as a trainer) who is in communication with the apparatus (via remote control and/or the internet, for example). 
         [0050]    Those skilled in the art will also recognize that other types of input devices and/or displays may be used without departing from the scope of the present invention. For example,  FIG. 5  shows an alternative user interface  200  with two alternative displays of the relative amounts of work performed by a user&#39;s upper body and lower body. A first, digital display  202  shows the percentage of work performed by the user&#39;s upper body adjacent to the percentage of work performed by the user&#39;s lower body. A second, analog display includes a scale  204  and an indicator  206  which moves along the scale  204  to indicate the percentage of work being performed by whichever portion of the user&#39;s body is currently performing the majority of the work. The user interface  200  also includes three LED displays  207 - 209  which may be alternatively lit to indicate the relationship between the user&#39;s current distribution of work and the user&#39;s target distribution of work. More specifically, the illumination of display  207  signals the user to increase the effort on upper body exercise; the illumination of display  208  signals the user to maintain the current distribution of work between upper body and lower body; and the illumination of display  209  signals the user to increase the effort on lower body exercise. Those skilled in the art will recognize that audible signals may used together with or in place of visible signals. 
         [0051]    Another alternative user interface  210  is shown in  FIG. 6 . Two analog displays are aligned relative to one another to facilitate a visual comparison between the target distribution of work and the actual distribution of work. Each display includes an identical scale  214  and a respective indicator  216  or  218 . The “target” indicator  216  moves along the upper scale  214  to indicate the user&#39;s target distribution of work between upper body and lower body, and the “actual” indicator  218  moves along the lower scale  214  to indicate the user&#39;s actual distribution of work between upper body and lower body. If desired, all of the foregoing displays may be enhanced to distinguish between the left and right sides of the person&#39;s body, as well. 
         [0052]    The present invention may be implemented in various ways and/or to achieve various results. For example, another embodiment of the present invention is shown in  FIG. 7 . As suggested by the common reference numerals, the apparatus  250  is similar to the first embodiment  100 , except for the rocker link  260 , the handlebar  270 , and the manner in which they are connected to one another and the frame  110  at connection assembly  280 . In particular, a steel hub  256  is rotatably mounted on frame member  116 , and a resilient member  286  is mounted on and about the hub  256  and keyed thereto, and a steel plate  266  is mounted on and about the resilient member  186  and keyed thereto. In other words, the resilient member  286  is interconnected between the hub  256  and the plate  266 . Both the rocker link  260  and the handlebar  270  are rigidly secured to the plate  266 . In response to the application of user force against the handle  277 , the resilient member  286  is compressed between the plate  266  and the hub  256 , causing the strip  178  to experience strain as a function of such force. 
         [0053]    Another, related embodiment may be implemented by switching each connection assembly  280  with a respective pivot joint  156  defined between the rocker link  260  and the foot supporting link  150 . Yet another approach is to form the handlebars and respective rocker links as unitary pieces and place suitable sensors on the handle portions  277  of the handlebars or between the handlebars and movable handgrips on the handlebars. Sensors may be connected to the foot supports  155 , as well or in the alternative. 
         [0054]    Still another embodiment of the present invention is designated as  300  in  FIG. 8 . The exercise apparatus  300  includes a frame  310  designed to rest upon a floor surface, and a leg exercise assembly similar to that on the first embodiment  100 . Among other things, the leg exercise assembly includes left and right foot supporting links  350  having forward ends rotatably connected to lower ends of respective rocker links  360 . An intermediate portion of each foot supporting link is sized and configured to support a person&#39;s foot, and is constrained to move through a generally elliptical path. 
         [0055]    An intermediate portion of each rocker link  360  is rotatably connected to the frame  310  at pivot axis Q. Left and right handlebars  370  have respective lower ends rotatably connected to respective rocker links  360  at respective pivot axes R (disposed a distance above the pivot axis Q). An opposite, upper end  377  of each handlebar  370  is sized and configured for grasping by a person standing on the foot supporting links  350 . 
         [0056]    An upper end  365  of each rocker link  360  is configured to provide an arcuate slot  367  which is centered about a respective pivot axis R. A respective block  385  is movably mounted within each slot  367 , and is rigidly secured to an intermediate portion of a respective handlebar  370  (by means of a bolt  375 , for example). First and second resilient members  387  are preferably disposed in respective gaps defined between opposite sides of the block  385  and opposite ends of the slot  367  to bias the handlebar  370  toward an aligned orientation relative to the rocker link  360 . On this embodiment  300 , the resilient members  387  are helical coil springs, but rubber blocks may be used in the alternative. 
         [0057]    In the absence of user force applied against the handles  377 , the handlebars  370  pivot in synchronized fashion together with respective rocker links  360 . However, the resilient members  387  allow the handlebars  370  to be forcibly moved relative to respective rocker links  360  at the discretion (and strength) of the user. The embodiment  300  is shown without strain gauges or other sensors to emphasize that (1) the “flexible synchronization” feature; (2) the “responsive resistance” feature; and (3) the “display of work distribution” feature may implemented independent of each other, as well as in various combinations. Additional examples of variability include replacing the resilient member  286  on the embodiment  250  with a similarly sized and shaped rigid member, and/or replacing the strip  178  on the embodiment  100  with a sufficiently strong bar rigidly secured to both the plate  176  and the hub  166 . 
         [0058]      FIG. 9  shows another user interface  400  suitable for use on various embodiments of the present invention, including the machine shown in  FIG. 1 . Like the other interfaces described herein, the interface  400  includes a display face that may be either a permanent arrangement or an image shown on a screen. A controller is placed in communication with both the display face and the strain gauges  188 . The controller operates in a manner similar to the controller described above with reference to the display  190 , but with a unique arrangement for data input and output. Among other things, the user interface  400  has a left side portion  410  that shows information primarily associated with strength exercise, a right side portion  420  that shows information primarily associated with cardio exercise, a bottom portion  430  that shows certain control information, and a central portion  440  that shows some general information associated with overall exercise. 
         [0059]    The left side portion  410  includes a “Strength” label and signal box  411  that is preferably set up to illuminate when strength exercise is being performed by the user and/or encouraged by the controller. Beneath the Strength “header” are various data displays associated with the user&#39;s performance of strength-type exercise. For example, bar graphs  414  show the current amount of relative work being performed by the user&#39;s upper body and lower body in terms of pushing and pulling motion. 
         [0060]    Below the bar graphs  414  is an array of boxes  416  that is lit sequentially from left to right as repetitions are performed during a strength phase of an exercise routine. When the row of boxes  416  is completely lit, it serves as a signal that the user has completed a satisfactory number of repetitions during that particular strength phase. At the successful conclusion of a strength phase, one of the boxes  446  in the central portion  440  of the display is lit. During each subsequent strength phase, the process is repeated. Below the “REPS” boxes  416  are data “read-outs”  418  that show the user&#39;s current strength effort and total strength effort in terms of upper body performance and lower body performance. 
         [0061]    The right side portion  420  includes a “Cardio” label and signal box  421  that is preferably set up to illuminate when cardio exercise is being performed by a user and/or encouraged by the controller. Beneath the Cardio “header” are various data displays associated with the user&#39;s performance of cardio-type exercise. For example, data “read-outs”  424  show the user&#39;s speed and the machine&#39;s current resistance setting. 
         [0062]    Below the read-outs  424  is an array of boxes  426  that is lit sequentially from left to right as “distance” is traversed during a cardio phase of an exercise routine. When the row of boxes  426  is completely lit, it serves as a signal that the user has successfully completed that particular cardio phase, and one of the boxes  446  in the central portion  440  of the display is lit. During each subsequent cardio phase, the process is repeated. Below the “TIME” boxes  426  are additional data “read-outs”  428  that show the user&#39;s effort in terms of calories burned. 
         [0063]    The lower portion  430  includes a control panel having various user input devices  433  and  435  that guide operation of the controller and/or the machine as suggested by their labels. The lower portion  630  also includes a display  437  of the user&#39;s heart rate, which requires a heart rate monitor that is either connected to the user or integrated into the handles  177  (all in a manner already known in the art). 
         [0064]    The central portion  440  of the interface  400  includes the column of boxes  446  that preferably light from bottom to top to tally completed phases of a workout. Above the boxes  446  is a “TOTAL TIME” read-out  444  to indicate how long the user has been exercising, and a two-headed arrow  442  that lights on the left end to indicate when strength exercise is being performed by the user and/or encouraged by the controller, and that lights on the right end to indicate when cardio exercise is being performed by the user and/or encouraged by the controller. The arrow  442  and the signal boxes  411  and  421  perform a similar task, and thus, may be used together or in lieu of one another. 
         [0065]    For added visual effect, the Cardio information and/or the right side  420  of the interface  400  may be highlighted and/or lit in a first color, such as red, and the Strength information and/or the left side  410  of the interface  400  may be highlighted and/or lit in a second color, such as blue. In addition, the information that is not “mode specific” may be highlighted and/or lit in a third color, such as green. During exercise activity, the screen may switch between cardio mode, wherein the Cardio box  421  is illuminated to the exclusion of the Strength box  411 , and strength mode, wherein the Strength box  411  is illuminated to the exclusion of the Cardio box  421 . The switching between modes may be prompted by a control program, input from the user, or a controller signal based upon the user&#39;s performance. Generally speaking, the controller will increase resistance to exercise in the strength mode, and decrease resistance to exercise in the cardio mode. 
         [0066]      FIG. 10  shows a user interface  500  that is similar in many respects to the previously described interface  400 . In fact, the only difference is that completed phases of exercise are tallied in a row of boxes  436  disposed in the lower portion  530  of the interface  500  (just below the left and right portions  410  and  420 ). 
         [0067]      FIG. 11  shows another user interface  600  suitable for use on various embodiments of the present invention, including the machine shown in  FIG. 1 . Like the other interfaces described herein, the interface  600  includes a display face that may be provided as either a permanent arrangement or an image on a screen. A controller is placed in communication with both the display face and the strain gauges  188  or comparable sensors on another machine. The controller operates in a manner similar to the controller described above with reference to the display  190 , but with a unique arrangement for data input and output. The user interface  600  has a left side portion  610  that shows information primarily associated with strength exercise, and a right side portion  620  that shows both information primarily associated with cardio exercise and certain control information. 
         [0068]    The left side portion  610  includes a “Strength” header box  611  that is preferably set up to illuminate when strength exercise is being performed (or encouraged). Beneath the Strength header box  611  is an array of smaller, “progress” boxes  612 . A column of boxes  612  is lit sequentially from bottom to top as repetitions are performed during a strength phase of an exercise routine. When a column of boxes  612  is completely lit, it serves as a signal that the user has completed a satisfactory number of repetitions during that particular strength phase. During the next strength phase, an adjacent column of boxes  612  is lit in similar fashion. When all of the columns of boxes  612  are lit, they serve as a signal that the user has satisfactorily completed all strength phases of the exercise routine. 
         [0069]    The left side portion  610  also includes an array of “read-out” boxes  614  associated with certain labeled performance measurements. These boxes  614  show specific data based on the user&#39;s current and total strength performance, as indicated by the adjacent labels. The left side portion  610  also includes an array of “relativity” boxes  616  that illustrate the relative amount of arm and leg force exerted separately in pushing and pulling fashion. A “cursor”  617  is continuously updated relative to the boxes  616  during strength exercise to show the current source of force being exerted. 
         [0070]    The right side portion  620  includes a “Cardio” header box  621  that is preferably set up to illuminate when cardio exercise is being performed (or encouraged). Beneath the Cardio header box  621  is an array of smaller, “progress” boxes  622  similar to the Strength progress boxes  612 . A column of boxes  622  is lit sequentially from bottom to top as exercise is performed during a cardio phase of an exercise routine. When a column of boxes  622  is completely lit, it serves as a signal that the user has satisfactorily completed a cardio phase. During the next cardio phase, an adjacent column of boxes  622  is lit in similar fashion. When all of the columns of boxes  622  are lit, they serve as a signal that the user has satisfactorily completed all cardio phases of the exercise routine. 
         [0071]    The right side portion  620  also includes an array of “read-out” boxes  624  associated with certain labeled performance measurements. These boxes  624  show specific data based on the user&#39;s current and total strength performance, as indicated by the adjacent labels. The right side portion  620  also includes a control panel  630  having a header panel  630  and various user input devices  633  that guide operation of the controller as suggested by their labels. The header panel  630  shows various information in response to user input and/or exercise activity, in order to assist a user in changing exercise parameters or programs, for example. 
         [0072]    Beneath the arrays of boxes  612  and  622 , some additional “read-out” boxes  636  are provided to display data regarding a user&#39;s overall exercise performance. The heart rate requires a heart rate monitor that is either connected to the user or integrated into the handles  177  (all in a manner already known in the art). 
         [0073]    For added visual effect, the Cardio information and/or the right side  620  of the interface  600  may be highlighted and/or lit in a first color, such as red, and the Strength information and/or the left side  610  of the interface  600  may be highlighted and/or lit in a second color, such as blue. In addition, the information that is not “mode specific” may be highlighted and/or lit in a third color, such as green. During exercise activity, the screen may switch between cardio mode, wherein the Cardio header  621  is illuminated to the exclusion of the Strength header  611 , and strength mode, wherein the Strength header  611  is illuminated to the exclusion of the Cardio header  621 . The switching between modes may be prompted by a control program, input from the user, or a controller signal based upon the user&#39;s performance. Generally speaking, the controller will increase resistance to exercise in the strength mode, and decrease resistance to exercise in the cardio mode. 
         [0074]      FIG. 12  shows another user interface  700  suitable for use on various embodiments of the present invention, including the machine shown in  FIG. 1 . Like the other interfaces described herein, the interface  700  includes a display face that may be either a permanent arrangement or an image on a screen. A controller is placed in communication with both the display face and the strain gauges  188  or comparable sensors on another machine. The controller operates in a manner similar to the controller described above with reference to the display  190 , but with a unique arrangement for data input and output. The user interface  700  has an upper left section  710  that shows information primarily associated with cardio exercise, an upper right section  720  that shows information primarily associated with strength exercise, and a lower middle section  730  that shows certain control information and general exercise information. 
         [0075]    The upper left section  710  includes a “Cardio” heading or label  711  that helps a user locate the cardio portion of the interface  700 . Along the outside perimeter of the cardio section  710  is a string of “progress” dots  712 . These dots  712  light sequentially from top to bottom as progress is being made during a cardio phase of an exercise routine. When the string of dots  712  is completely lit (or a single “cursor” light has progressed all the way to the bottom), it serves as a signal that the user has satisfactorily completed a cardio phase, and an appropriate one of the “Sets” dots  713  is lit in the control section  730  of the display. During the next cardio phase, the same string of dots  712  is lit in similar fashion, followed by another Sets dot  713 . When all of the Sets dots  713  are lit on the left side of the control section  730 , they serve as a signal that the user has satisfactorily completed all cardio phases of the exercise routine. 
         [0076]    Beneath the cardio label  711 , the upper left section  710  also includes an array of “read-out” boxes  714  associated with certain performance measurements. These boxes  714  show specific data based on the user&#39;s current and total cardio performance, as indicated by the adjacent labels. Also, graphs and/or meters may be provided to provide graphic illustrations of cardio exercise performance. For example, one such meter  716  is provided in the upper left section  710  to illustrate the level or inclination of the user&#39;s foot path. 
         [0077]    The upper right section  720  includes a “Strength” heading or label  721  that helps a user locate the strength portion of the interface  700 . Along the outside perimeter of the strength section  720  is a string of “progress” dots  722 . These dots  722  light sequentially from top to bottom as repetitions are performed during a strength phase of an exercise routine. When the string of dots  722  is completely lit (or a single “cursor” light has progressed all the way to the bottom), it serves as a signal that the user has satisfactorily completed a strength phase, and an appropriate one of the “Sets” dots  723  is lit in the control section  730  of the display. During the next strength phase, the same string of dots  722  is lit in similar fashion, followed by another Sets dot  723 . When all of the Sets dots  723  are lit on the right side of the control section  730 , they serve as a signal that the user has satisfactorily completed all strength phases of the exercise routine. 
         [0078]    Under circumstances where the number of depicted dots (of any type) differs from the scheduled or preferred exercise routine, the controller can compensate in various ways. For example, if a user is going to perform only 10 repetitions during a strength phase, then the program can light (or traverse) three dots after every two repetitions, or light the first six dots after performance of the first repetition. On the other hand, if a user is going to perform 20 repetitions during a strength phase, then the program can light (or traverse) three dots after every four repetitions, or strobe the first dot during each of the first five repetitions before beginning to sequentially light (or traverse) the dots. A similar approach may be taken with regard to distance during cardio phases, and/or sets accumulated in the control section. 
         [0079]    The upper right section  720  also includes an array of “read-out” boxes  724  associated with certain performance measurements. These boxes  724  show specific data based on the user&#39;s current and total strength performance, as indicated by the adjacent labels. Also, graphs and/or meters may be provided to provide graphic illustrations of strength exercise performance. For example, respective meters  726  are provided in the upper right section  720  to illustrate the relatively amounts of pushing and pulling performed by a person&#39;s arms and legs. 
         [0080]    The control section  730  includes a header or label that helps a user locate the control portion of the interface  700 . A display area  731  is provided in the control section  730  to display various messages to the user in response to user input and/or exercise activity, in order to assist a user in changing exercise parameters or programs, for example. Also, various user input devices  733  are provided in the control section  730  to facilitate operation of the controller as suggested by their labels. Furthermore, in addition to the Sets dots  713  and  723 , some additional “read-out” boxes  736  are provided to display data regarding a user&#39;s overall exercise performance. The heart rate display requires a heart rate monitor that is either connected to the user or integrated into the handles  177  (all in a manner already known in the art). 
         [0081]    For added visual effect, the various sections of the interface  700  may be highlighted and/or lit in discrete colors, and/or the perimeter (including associated borders  707 ) of the “active” section may illuminate to draw the user&#39;s attention. Also, the Sets dots  713  and  723  may be illuminated in the respective colors of their related sections to help maintain a connection therebetween. During exercise activity, the screen may switch between cardio mode, strength mode, and control mode, as prompted by a control program, input from the user, or a controller signal based upon the user&#39;s performance. Generally speaking, the controller will increase resistance to exercise in the strength mode, and decrease resistance to exercise in the cardio mode. 
         [0082]      FIG. 13  shows another user interface  700 ′ suitable for use on various embodiments of the present invention, including the machine shown in  FIG. 1 . As suggested by the common reference numerals, the interface  700 ′ is similar in many respects to the interface  700 . In fact, the only difference is the arrangement of the control panel portion  750  of the interface  700 . The user input devices  753  are arranged in an arc along the bottom of the control section  750 . These devices  753  include a Switch Panels input device  754  that allows the user to promptly switch among the three sections  710 ,  720 , and  750 . For example, if the cardio section  710  is active, and the user operates the Switch Panels input device  754 , then the control section  750  becomes active, and if the user operates the Switch Panels input device  754  again, then the strength section  720  becomes active. The Control Panel label is centrally located just above the input devices  753 , and just below the display area  751 . The Total Time “read-out”  756  is centrally located at the top of the section  750 . 
         [0083]      FIG. 14  shows another user interface  800  suitable for use on various embodiments of the present invention, including the machine shown in  FIG. 1 . Like the other interfaces described herein, the interface  800  includes a display face that may be either a permanent arrangement or an image on a screen. A controller is placed in communication with both the display face and the strain gauges  188  or comparable sensors on another machine. The controller operates in a manner similar to the controller described above with reference to the display  190 , but with a unique arrangement for data input and output. The user interface  800  has a generally upper left section  810  that shows information primarily associated with cardio exercise, a generally upper right section  820  that shows information primarily associated with strength exercise, and a lower middle section  830  that shows certain control information and overall exercise information. 
         [0084]    The upper left section  810  includes a “Cardio” heading or label  811  that helps a user locate the cardio portion of the interface  800 . Along the outside perimeter of the cardio section  810  is a string of “progress” dots  812 . These dots  812  light sequentially from bottom to top as progress is being made during a cardio phase of an exercise routine. When the string of dots  812  is completely lit (or a single “cursor” light has progressed all the way around to the center of the display  800 ), it serves as a signal that the user has satisfactorily completed a cardio phase, and an appropriate one of the “Sets” dots  813  is lit in the “Sets” box  838 . During the next cardio phase, the same string of dots  812  is lit in similar fashion, followed by another Sets dot  813 . When all of the Sets dots  813  are lit on the left side of the Sets box  838 , they serve as a signal that the user has satisfactorily completed all cardio phases of the exercise routine. 
         [0085]    Beneath the cardio label  811 , the upper left section  810  also includes an array of “read-out” boxes  814  associated with certain performance measurements. These boxes  814  show specific data based on the user&#39;s current and total cardio performance, as indicated by the adjacent labels. Although not shown on this embodiment, graphs and/or meters may be included to provide graphic illustrations of cardio exercise performance, as well. 
         [0086]    The upper right section  820  includes a “Strength” heading or label  821  that helps a user locate the strength portion of the interface  800 . Along the outside perimeter of the strength section  820  is a string of “progress” dots  822 . These dots  822  light sequentially from bottom to top as repetitions are performed during a strength phase of an exercise routine. When the string of dots  822  is completely lit (or a single “cursor” light has progressed all the way around to the center of the display  800 ), it serves as a signal that the user has satisfactorily completed a strength phase, and an appropriate one of the “Sets” dots  823  is lit in the “Sets” box  838 . During the next strength phase, the same string of dots  822  is lit in similar fashion, followed by another Sets dot  823 . When all of the Sets dots  823  are lit on the right side of the Sets box  838 , they signal that the user has satisfactorily completed all strength phases of the exercise routine. 
         [0087]    As discussed above with reference to the preceding embodiment  700 , when the number of depicted dots (of any type) differs from the scheduled or preferred exercise routine, the controller can compensate in various ways. For example, if a user is going to perform only 10 repetitions during a strength phase, then the program can light (or traverse) two dots after every repetition, or light the first eleven dots after performance of the first repetition. On the other hand, if a user is going to perform 30 repetitions during a strength phase, then the program can light (or traverse) two dots after every three repetitions, or strobe the first dot during each of the first ten repetitions before beginning to sequentially light (or traverse) the dots. A similar approach may be taken with regard to distance during cardio phases, and/or sets accumulated in the control section. 
         [0088]    The upper right section  820  also includes an array of “read-out” boxes  824  associated with certain performance measurements. These boxes  824  show specific data based on the user&#39;s current and total strength performance, as indicated by the adjacent labels. Although not shown, graphs and/or meters may be included to provide graphic illustrations of strength exercise performance, as well. 
         [0089]    The control section  830  is spread out beneath the other sections  810  and  820  and between the progress dots  812  and  822 . The control section  830  includes the sets box  838 , which is aligned with the proximate ends of the strings of dots  812  and  822  (to provide a visual connection between the dots associated with a single phase and the dots associated with completed phases). A display area  832  is provided in the control section  830  to display various messages to the user in response to user input and/or exercise activity, in order to assist a user in changing exercise parameters or programs, for example. The section  830  also includes header or label  831  that helps a user locate the control portion of the interface  800 . Also, various user input devices  833  are provided in the control section  830  to facilitate operation of the controller as suggested by their labels. Furthermore, a “Total Time” box  856  is provided at an upper middle location. 
         [0090]    For added visual effect, the various sections of the interface  800  may be highlighted and/or lit in discrete colors. Also, the Sets dots  813  and  823  may be illuminated in the respective colors of their related sections to help maintain a connection therebetween. During exercise activity, the screen may switch between cardio mode, strength mode, and control mode, as prompted by a control program, input from the user, or a controller signal based upon the user&#39;s performance. Generally speaking, the controller will increase resistance to exercise in the strength mode, and decrease resistance to exercise in the cardio mode. 
         [0091]      FIGS. 15-16  show a user interface  900  having a right side portion  930  that remains the same, and a left side portion that changes between a “Cardio” display (designated as  910  in  FIG. 15 ) and a “Strength” display (designated as  920  in  FIG. 16 ). The right side portion  930  includes a control panel  931  having a heading area and various user input sensors  933  beneath the heading area. These sensors  933  include a “Switch Screens” sensor that allows a user to toggle between the Cardio display  910  and the Strength display  920 . The right side portion  910  also includes a display area  939  that shows various information in response to user input and/or exercise activity. 
         [0092]    The right side or common portion  930  further includes a centrally located “Sets” counter area  934 , and a centrally located “Total Time” display  938 . The Sets area  934  includes a first column of dots  941  that aligns with a string of dots  914  in the Cardio display  910 , and a second column of dots  942  that aligns with a string of dots  924  in the Strength display  920 . 
         [0093]    When the interface  900  is in the cardio mode, the “Cardio” display  910  appears on the left portion of the interface  900  to show various information about the user&#39;s current cardio performance and total cardio performance. As suggested by the labels associated with the “read-outs”  912 , some of the total performance data may be displayed in terms of an average, while other such data may be displayed in terms of a total. The “Cardio” display also includes a series of “Progress” indicators or dots  914  that extend up and around the display  900  and terminate at the top of the left hand column in the “Sets” counter area  934 . 
         [0094]    When the interface  900  is in the strength mode, the “Strength” display  920  appears on the left portion of the interface  900  to show various information about the user&#39;s current strength performance and total strength performance. The labels associated with the “read-outs”  922  suggest the type of information that may be displayed. The “Strength” display also includes a series “Progress” indicators or dots  924  that extend up and around the display  900  and terminate at the top of the right hand column in the “Sets” counter area  934 . 
         [0095]    The interface  900  is preferably programmed to switch the left side portion between the “Cardio” display  910  and the “Strength” display  920  whenever a switch is made between modes of exercise. The switch may be performed in response to a control signal from a program, and/or a user can manually switch between the “Cardio” display  910  and the “Strength” display  920  by touching or pressing the “Switch Screens” sensor  931  in the Control Panel. Also, the switch may occur in response to sensor input that indicates the user is performing work with his/her arms in excess of a threshold amount of work, and/or is performing more than a threshold percentage of total work with his/her arms. 
         [0096]    The present invention may also be described in functional terms along the following lines. On an exercise apparatus comprising a frame designed to rest upon a floor surface; an arm supporting member; and a leg supporting member, wherein at least one of the supporting members is movably mounted on the frame, the present invention may be described in terms of (a) means for interconnecting the leg supporting member and the arm supporting member in such a manner that the path traversed by the user&#39;s hand is synchronized relative to the path traversed by the user&#39;s foot, until a threshold amount of user force is applied against the arm supporting member, in which case, the hand path may deviate from its otherwise synchronized path relative to the foot path; and/or (b) means for connecting the leg supporting member and the arm supporting member in such a manner that the path traversed by the user&#39;s hand is synchronized relative to the path traversed by the user&#39;s foot and movable against a resistance force which is measured and/or applied independent of the leg supporting member; and/or (c) means for displaying the distribution of work between a user&#39;s upper body and lower body. 
         [0097]    The present invention also may be said to provide various methods which may be implemented in various ways and/or described with reference to various embodiments; including the foregoing embodiments. One such method is to provide arm and leg supporting members which are both synchronized and subject to independent resistance. Another such method is to provide arm and leg supporting members which are both encouraged to remain synchronized and selectively movable relative to one another. Yet another method is to move a person&#39;s hands and feet through respective paths which are synchronized relative to one another, while allowing deviation from the synchronized path in response to user applied force and/or providing separate resistance to movement along the respective paths. Yet another method is to measure and/or display work performed separately by a person&#39;s upper body and lower body. 
         [0098]    The present invention may also be described with reference to the user interfaces shown in  FIGS. 9-16 . As previously noted, these interfaces may be substituted for the interface  190  on the elliptical exercise machine  100 , and/or they may used on other suitable exercise apparatus. Whereas the interface  190  distinguished between upper and lower body exercise, the interfaces shown in  FIGS. 9-16  distinguish between exercise performed during one or modes of aerobic or cardio exercise, and exercise performed during one or modes of anaerobic or strength exercise. The particular mode of exercise may be determined manually by a user or a user&#39;s activity, or automatically by a control program. Also, each mode of exercise may be characterized simply by a change in designation, or by a change in an exercise parameter, such as the level of resistance or the relative amount of arm exercise. For example, cardio exercise may be associated with resistance below a threshold value, and strength exercise may be associated with resistance above the threshold value. 
         [0099]    The foregoing embodiments and associated methods are representative but not exhaustive examples of the subject invention. It is to be understood that the embodiments and/or their respective features may be mixed and matched in a variety of ways to arrive at other embodiments. For example, the control and/or display options described with reference to a particular embodiment are applicable to other embodiments, as well. Moreover, additional and/or alternative sensors may be located elsewhere on the equipment to measure force and/or compare upper body and lower bodywork. For example, sensors may be placed in or near the hand grips and/or in or near the foot supports. In conclusion, recognizing that this disclosure will lead those skilled in the art to recognize additional embodiments, modifications, and/or applications which fall within the scope of the present invention, the scope of the present invention is to be limited only to the extent of the claims which follow.