(12) Patent Application Publication (10) Pub. No.: US 2012/ A1

Transcription

1 (19) United States US A1 (12) Patent Application Publication (10) Pub. No.: US 2012/ A1 Dreissigacker et al. (43) Pub. Date: Apr. 26, 2012 (54) EXERCISING (52) U.S. Cl /72 (76) Inventors: Dick Dreissigacker, Morrisville, (57) ABSTRACT VT (US); Peter D. Dreissigacker, Stowe, VT (US) (21) Appl. No.: 12/909,901 (22) Filed: Oct. 22, 2010 Publication Classification (51) Int. Cl. A63B 69/06 ( ) P2 Among other things, an exercise machine includes a resis tance device connected to a flexible driving line used to drive the resistance device. A flexible exercise line receives forces applied by the user's hands and feet during cycles of exercis ing. A force transfer mechanism couples forces, received on the exercise line from the user during exercising, to the resis tance device during the exercise cycles, and moves back and forth relative to a frame of the machine. The force transfer mechanism rides along, and is Supported vertically, by a Support during use of the machine.

2 Patent Application Publication Apr. 26, 2012 Sheet 1 of 14 US 2012/ A1 132

3 Patent Application Publication Apr. 26, 2012 Sheet 2 of 14 US 2012/ A1 FIG. 2

4 Patent Application Publication Apr. 26, 2012 Sheet 3 of 14 US 2012/ A1 115

5 Patent Application Publication Apr. 26, 2012 Sheet 4 of 14 US 2012/ A1

6 Patent Application Publication Apr. 26, 2012 Sheet 5 of 14 US 2012/ A1 FIG. 4

7 Patent Application Publication Apr. 26, 2012 Sheet 6 of 14 US 2012/ A1

8 Patent Application Publication Apr. 26, 2012 Sheet 7 of 14 US 2012/ A1 D 199 O 192 Y^N. K \ \ e. s y

9 Patent Application Publication Apr. 26, 2012 Sheet 8 of 14 US 2012/ A1

10 Patent Application Publication Apr. 26, 2012 Sheet 9 of 14 US 2012/ A1 Fry 106 G

11 Patent Application Publication Apr. 26, 2012 Sheet 10 of 14 US 2012/ A & S 125 FIG. 9

12 Patent Application Publication Apr. 26, 2012 Sheet 11 of 14 US 2012/ A1

13 Patent Application Publication Apr. 26, 2012 Sheet 12 of 14 US 2012/ A S S N 161 S

14 Patent Application Publication Apr. 26, 2012 Sheet 13 of 14 US 2012/ A t 129 FIG. 12

15 Patent Application Publication Apr. 26, 2012 Sheet 14 of 14 US 2012/ A , rasa r 1 1 O --a w a. ---

16 US 2012/ A1 Apr. 26, 2012 EXERCISING This application is related to U.S. patent application Ser. No. 12/572,869, filed Oct. 2, 2009, and incorporated here in its entirety by reference. BACKGROUND 0002 Exercising is frequently done on an exercise machine in which motion of the exerciser's arms or legs is resisted by a resistance device Such as a rotating fan. In some rowing machines, for example, as a user simulates a rowing cycle, a seat holding the user glides back and forth along the frame in response to the user applying force to a handle and a foot rest. In some rowing machines, the resistance device moves back and forth on the frame in response to the forces. SUMMARY In general, in an aspect, an exercise machine includes a resistance device connected to a flexible driving line used to drive the resistance device. A flexible exercise line receives forces applied by the user's hands and feet dur ing cycles of exercising. A force transfer mechanism couples forces, received on the exercise line from the user during exercising, to the resistance device during the exercise cycles, and moves back and forth relative to a frame of the machine. The force transfer mechanism rides along, and is Supported Vertically, by a Support during use of the machine Implementations may include one or more of the following features. The force transfer mechanism slides on the Support. The force mechanism rides along a direction corresponding to the directions of the forces applied by the user's hands and feet. The Support comprises a rail. The Support includes a mechanism to reduce friction as the force transfer mechanism rides along the Support. The friction reducing mechanism includes a material. The material com prises a layer. The layer lies between the force transfer mecha nism and the Support. The Support includes a mechanism to reduce noise from the movement of the force transfer mecha nism on the Support. The noise reducing mechanism includes a material. The material comprises a layer. The layer lies between the Support and a layer of a friction reducing mate rial. The Support is positioned below a rail connected to a seat for the user and a foot rest assembly that receives the force applied by the user's feet. One end of the support and the rail are attached to a structural element and the other end of the Support and the rail are attached to the resistance device to constitute a frame for the machine. The force transfer mecha nism has at least one side piece having a bearing Surface that rides on the Support. The force transfer mechanism is con nected to a resilient flexible line. The resilient flexible line applies a force on the force transfer mechanism to take up slack in the flexible exercise line during parts of the exercise cycle when the user is applying less force than other parts of the exercise cycle. The force applied by the resilient flexible line is as low as 3 pounds These and other aspects and features, and combina tions of them, can be expressed as methods, apparatus, means for steps for performing functions, systems, components, and applications, and in other ways Other aspects and features will be apparent from the following description, and from the claims. DESCRIPTION 0007 FIG. 1 is a perspective view of an exercise machine, partially exploded FIG. 2 is a side view (partially broken away) and FIG. 4 a schematic side view of exercise machines FIGS. 3A-3D are illustrations of phases of a rowing cycle. (0010 FIG. 5 is a perspective view, FIG. 6 a side view, and FIG. 7 a rear view of exercise machines FIG. 8 is a partially see-through side view of an exercise machine. (0012 FIGS are side and perspective views of part of a transfer mechanism FIG. 11 is a cross-section of part of an exercise machine. 0014) FIGS. 12 and 13 are side views of an exercise machine Referring to FIGS. 1 and 2, in some implementa tions, a rowing exercise machine 100 can be arranged to simulate for a user the rowing of a shell (or other rowing platform) through water (in a river, for example), while achieving other advantages, including reducing the effort required by the user to overcome inertia of his body during different stages of a rowing cycle, and offering the possibility of achieving compact size and Weight and economical cost of the machine. These and other benefits can be achieved, for example, by connecting a non-resilient flexible cable 104 (for example, one that has a tensile strength to resist stretching when pulling forces are applied to its ends) through pulleys between an exercise handle 102 and a movable foot rest 112. Then the combined force 121 corresponding to a force 117 applied to the handle and a force 119 applied to the foot rest at various times during a rowing cycle can be coupled through a pulley assembly 115 and a chain 116 to work against and drive a fan or other resistance device 132 (which in the example shown is fixed to the frame). In the example, the force at the resistance device will be half of the combined force 121 because of the configuration of the pulleys As a result, as the user sitting on a movable seat 118 works through a rowing cycle during parts of which he or she pulls on and lets up on the handle and pushes or pulls or lets up on the foot rest the handle, the foot rest, and the seat can move back and forth 140, 152, 153 along a rail 126 that is part of a frame 129 of the machine, to provide a more realistic rowing experience, among other benefits The rowing machine 100 simulates, for example, the effect that motion of a shell underneath a rower as the shell glides through the water has on the motion of the rower's feet relative to his torso, among other things. Among other things, because the foot rest 112 can move along the main rail 126 as the user applies force to the foot rest and the handle, the exercise machine 100 simulates the inertia, resistance, and motion experienced by a rower when he rows a shell on water In some implementations, the resistance device 132 is attached in a fixed position along the length of the main rail 126 of the exercise machine, which allows the frame to be shorter, lighter weight, and less expensive to make, than if the resistance device were arranged to move along the rail. In Some implementations, some motion of the resistance device relative to the frame could be permitted.

17 US 2012/ A1 Apr. 26, In some examples, the resistance device 132 includes an air resistance fan, for example, of the kind shown in U.S. Pat. No. 6,561,955, incorporated hereby reference. In Some implementations, the resistance device can be an elec trical device or a friction device, for example In some implementations that use an air resistance fan, the fan rotates on a central spindle 139. In some examples, a driving sprocket wheel 134 is attached by a one-way clutch (not shown) to the spindle. The one-way clutch enables the sprocket wheel to rotate the fan when the sprocket wheel is driven in one rotational direction 135 and allows the sprocket wheel to rotate freely relative to the fan when the sprocket wheel is driven in the opposite rotational direction 136. A wide variety of other drive arrangements could be used for the fan In some cases, the cable 104 extends from the handle through free-wheeling pulleys 106, 110, and 114 (which is part of the pulley assembly 115) and is attached at its other end to a location 601 on a bracket 602 that is part of a foot rest assembly In some examples, a chain 116 drives the sprocket wheel as the chain moves. One end of the chain can be attached at a fixed point 137. The part of the chain between the fixed attachment point 137 and the sprocket wheel passes through a free running pulley 120 that is part of the pulley assembly 115. The other end of the chain is connected by a coupling 206 to a resilient cord 202 the other end of which is attached to a second fixed point When the pulley assembly 115 is pulled to the right in response to the combined force 121, the pulley 120 pulls on the cable 116 causing the cable to drive the sprocket wheel in the direction 135. The coupling 206 moves to the left, and the cord 202, which passes through a free wheeling pulley 204, stretches. The force needed to extend the cord is relatively small compared to the force needed to drive the fan. When the combined force 121 on the pulley assembly falls below the restoring force exerted by the stretched cord, the stretched cord 202 contracts, pulling in the slack of the chain During a rowing cycle, the user applies various forces to the handle, the foot rest, and the seat, and the fan resists the combined forces applied to the handle and the foot rest. At times during the cycle, the user applies essentially no force on the handle, and allows the cable 104 to be taken up by a force on the foot rest or the restoring force of the cord, or both. At times during the cycle, the user applies essentially no force 119 on the foot rest and allows the foot rest to move to the left on FIG. 2, or may pull the foot rest back using a foot strap (not shown). Various combinations of Such forces and motion may also occur. The machine is arranged so that the forces applied and the motions of the handle, foot rest, and seat will simulate rowing a shell through water In general, the combined forces on the handle and the foot rest are applied to perform work against the resistance device. Essentially there is no net force acting on the user to move the seat either to the left or to the right. As a result, there need not be any motion of the seat 118 in either direction 153 during a rowing cycle. Although motion of the seat is not necessary, a small movement of the seat 153 may occur as the user shifts his upper body mass from one portion of the rowing cycle to another portion. Typically, the Small motion of the seat will be in the direction opposite to the motion of the user's torso. For example, as the user pushes hard on the foot rest and pulls hard on the handle, he will also tend to shift his body mass away from the foot rest, causing the seat to move slightly towards the footrest As shown in FIG. 3A, when a user is about to begin a stroke portion of a rowing cycle, the rower 101 may be crouched, with a location 217 on the foot rest 112 at a position P1 (along the length of the exercise machine) and a center location 219 of the seat 118 at a position P2 so that the distance between P2 and P1 is As the user starts the rowing stroke, the user pulls back 117 on the handle 102 towards the user's torso, and at the same time may push 119 on the foot rest. The resulting combined force 121 (e.g., the sum of the forces applied on the footrest and on the handle) performs work through the chain 116 and the sprocket wheel 134 to drive the resistance device. The resistance device resists the force, and the work per formed by the user exercises the user's muscles. In the example of FIG. 2, the force on the resistance device is half the combined force 121, due to the arrangement of the pulley 114. Other arrangements of pulleys can provide other multi plications or divisions of force and distance traversed with respect to the work performed by the user As shown in FIG. 3B, during the stroke, the user pushes hard on the foot rest and pulls hard on the handle, which causes the handle to move toward historso and the foot rest to move away from historso. The combined forces on the handle and the foot rest drive the fan. Although not required, the user's torso and the seat also may move a small distance toward (or, depending on the way the user chooses to shift his torso, away from) the handle and foot rest as the user shifts his body mass As shown in FIG.3C, at the end of the stroke portion of the rowing cycle, the user has fully extended his legs and fully extended the handle. The location 217 on the footrest is then at position P3, which is a distance 229 from P1 that is Substantially larger than distance 221, yet the seat had moved very little if at all After reaching the end of the stroke, the user goes through a recovery portion of the rowing cycle, illustrated in FIG. 3D, to return to the original position shown in FIG. 3A. As shown in FIG. 3D, during recovery, the user stops pulling on the handle, allowing it to withdraw to the right, may pull on the foot rest against a typical foot strap, not shown, and retracts his legs. He may shift historso (and therefore the seat) a small distance, typically to the left. These actions cause the combined force 121 to drop below the small restoring force asserted by the stretched cord. So the cable 104 relaxes, allowing the pulley assembly 115 to move to the left and the slack in the chain to be taken up by the contracting cord Therefore, in the examples being discussed, during the stroke and recovery there is relatively large motion back and forth of the handle and the foot rest, with work being done against the fan during the stroke. There can be some motion of the seat back and forth, but the motion is relatively small. Rowing on water is effectively simulated and, because the resistance device need not move back and forth also, the machine can be compact In some implementations, as shown in FIGS. 1 and 2, the rail has a generally u-shaped cross-section 491 for strength and accessibility. The u is open at the bottom and the bottom edges of the sides 493, 495 of the u are connected to short extensions 497, 499 that project perpendicularly into and partially obstruct the opening of the u at the bottom of the u-shaped cross-section. The front end of the rail 126 is

18 US 2012/ A1 Apr. 26, 2012 attached between a pair of vertical posts 108. The pulley 106 is also supported between the two posts 108. The pulley 204 is mounted within the u-shaped cross-section near the front of the rail 126. A monitor 199 with controls is accessible to the user at one end of an arm 193. The other end of the arm can pivot on one end of a main arm 192, the other end of which is attached to the posts 108. The bottoms of the posts 108 are attached to a foot At its other end, the rail 126 is supported on an assembly 189. The assembly 189 includes a foot 133, a leg 235, and two supports 237 that bear a pair of parallel cylin drical rails 1199, 1196 along which the seat can ride on four wheels 127 (not all shown). Brackets 239 prevent the seat from being removed from the assembly 189. The assembly also includes two structural pieces 241, In some implementations, the mounting of the seat can include a restraining or centering mechanism that urges the seat toward a central home location along its supporting rails. The mechanism could be an elastic centering device that connects the seat to the Supporting assembly. In some examples, the rails can have a slightly curved contour with a low point at the center of travel The foot rest includes two plates 112 for the user's two feet, each mounted on a vertical bracket 312. Each ver tical bracket bears a pair of upper wheels 113 that ride along the top of the rail 126 and a bottom wheel 111 that rides along the bottom of the rail 126. The wheels also keep the foot rest in place and prevent it from being removed from the rail. The bracket 602 is mounted between the two brackets 312. A hook 195 is mounted to project from the foot rest assembly to receive the handle when not in use. A wide variety of struc tures and components and their interaction can be used to achieve the benefits described. These include a wide variety of devices, including cables, chains, cords, straps, and other schemes to transmit forces between the handle and the foot rest. In some cases, there may be some resilience in the force transmitting device to provide selected dynamic characteris tics A wide variety of transfer mechanisms can be used to transfer the combined force on the cable to drive the resis tance device. Other pulley arrangements are possible, and the transfer mechanism need not include pulleys. In some imple mentations in which the element that transmits force between the handle and the footrest is a line, like a cable or cord, for example, the force transmitting mechanism needs to permit the line to slide back and forth freely as forces change, while still transmitting the combined force to the resistance device In some examples of an exercise machine 500, as shown in FIG. 4, a pulley assembly includes a single pulley 402. A cable 504 is connected at one end to foot rest 112, passes through the single pulley, and is connected at the other end to the handle 102. The spindle of the pulley 402 is con nected to the resistance device by a chain 406. The other end of the chain is attached through a coupling 414 to a resilient cord 412, the other end of which is attached at a fixed location 407. In these examples, the combined force is not halved by the pulley assembly and equals the force applied to the resis tance device In some implementations of an exercise machine 100, shown in FIGS.5-7, a second rigid structural rail 125 (for example, of steel) is attached parallel to and below the first rail 126. A front end 123 of the rail 125 is secured (for example, by bolts 180) between the two vertical posts 108. At the other end 124, the rail 125 is supported (for example, by bolts 181) on the assembly 189. Below the rail 125 a third rigid structural rail 128 (for example, of steel) is attached to the machine. The rail 128 is attached to the assembly 189 (for example, by bolts 182), and extends along the bottom of the rail 125 and ends short of the vertical posts 108. The rail 128 can be attached to the rail 125 by bolts or an adhesive The second rail 125 houses and vertically supports the pulley assembly 115 or other transfer mechanism. Because the transfer mechanism is Supported vertically, there is no risk of the transfer mechanism dangling towards the ground if the tension on the cables that run through the mechanism is low. As a result, that tension on cord 202 may, if desired, be made deliberately low (for example, a tension as low as 3 pounds, or even lower in some examples, in the horizontal direction 109). A low tension may more accurately simulate rowing a shell through water during the parts of the cycle, namely the recovery, illustrated in FIG. 3D, when the user is not applying much if any force to the handles and pedals, while preventing the pulley assembly 115 from dan gling towards the ground under the influence of gravity Referring to FIG. 11, the rail 125 is formed of a floor 148 and two parts of a ceiling 149a, 149b joined by side walls 150, 151. The ceiling 149 has a slot along its length to give access for repairing or adjusting the mechanism. The cross section of the rail 128 is a u-shape with side walls 160, 161 and a ceiling 162. The open bottom allows for easy access for maintenance and repair to the pulleys and cables housed within Referring to FIGS. 9 and 10, the pulley assembly 115 has parallel steel plates 702, 703 on each side of the assembly 115. The pulley assembly 115 can ride back and forth 121, 122 along the length of the support rail 125 on the bottom edges 712,713 of the two plates 702, 703 of the pulley assembly 115. The floor 148 of the rail 125 may have a thin layer of a material 705, such as plastic (for example, polyeth ylene), to reduce the friction between the floor of the rail 125 and the edges 712,713 of the two plates 702, 703 of the pulley assembly 115. This arrangement minimizes wear and reduces the drag felt by the rower during recovery, for example. The floor may also have another layer of material 710, between the floor and the material 705, such as foam, to reduce any noise while the pulley assembly 115 is sliding along the supportrail 125. The materials 705 and 710 can be attached using an adhesive. The pulleys 114, 120 are mounted on the pulley assembly 115 using bolts 185 through the plates 702, 703. The two plates 702, 703 extend beyond the bottoms of the pulleys 114, 120 to provide clearance for the sliding of the pulley assembly 115 relative to the rail 125 without affecting the rotation of the pulleys 114, Referring again to FIGS. 5-7, in some implementa tions, the general location of the rail 126 relative to the foot rest assembly 603 and the seat support 237 is higher than in the implementations of FIG. 1. As the rail 126 is attached higher relative to the foot rest assembly 603, the rail 126 is positioned between the two foot plates 112 for the user's feet. The vertical brackets 312 on which the foot plates 112 are mounted are then on the same horizontal level as the foot plates 112 and positioned toward the front posts By positioning the rail 126 higher relative to the foot assembly 603 and the seat support 237, there is more space between the rail 126 and the ground to place the second support rail 125 and the third rail 128. The higher rail 126 and the second rail 125 can both extend from the front vertical posts 108 to the rear assembly 189 with a space between the

19 US 2012/ A1 Apr. 26, 2012 two rails. This provides the basis for a frame for the machine that is structurally sound and also efficient in both space and production cost. 0044) Referring to FIG. 1, a cross-section 495 of the rail 126 can be seen. The rail 126 of the implementations in FIGS. 5-7 has a similar cross-section. The upper wheels 113 that ride on top of the rail 126 in the implementations of FIG. 1 are, in the implementations of FIGS. 5-7, on the inside of the rail 126 and ride on the short bottom extensions 497, 499 of the rail 126. Each upper wheel has a corresponding lower wheel 111 that rides along the bottom of the rail 126, resulting in four total pairs of wheels on the two vertical brackets Referring again to FIGS. 5-7, as the rail 126 is positioned higher relative to the foot rest assembly 603 and the seat support 237, the support 237 for the seat 118 may include a rail 238 raised slightly above the main rail 126. The seat 118 may slide back and forth 153 on this support 237 on pairs of wheels 127 (not shown), attached to the rail 238 in a manner similar to that of the foot rest assembly 603. In some implementations, the mounting of the seat can include a restraining or centering mechanism that urges the seat toward a central home location along its Supporting rails. The mechanism could be an elastic centering device 605 that connects the seat to the Supporting assembly. In some imple mentations, the rail 238 can have a slightly curved contour with a low point at the center of travel As shown in FIG. 8, in some implementations, one side of the pulley assembly 115 includes a pulley 114. A cable 104 extends from the handle 102 through free-wheeling pull leys 106, 110, and 114 to the foot rest 112. The other end of the pulley assembly 115 includes a pulley 120. A cable 116 is fixed at one end at one point 137 and passes through pulley 120 to drive the sprocket wheel 211. The cable continues through pulleys 203,204, and 205, and is attached at the other end to a point 138. These pulleys 203,204, 205 and the point 138 can be housed under the rail 125 in the rail 128. The point 138 and the pulley 204 are on a moveable block 206. This block is connected to the resilient cord 202 (for example, a bungee cord) that provides a force 109 to take up slack on the chain in the parts of the rowing cycle when the user is not exerting much force. The cord 202 extends through one coaxial pair of pulleys 208 on one end of the rail 128, and through another coaxial pair of pulleys 210 on the other end of the rail 128, traversing the length of the rail 128 four times before connecting to the axle of the pulley Because the force transfer mechanism is supported by the rail 125, the cord 202 does not need to apply a tension on the force transfer mechanism greater than the effect of gravity on the force transfer mechanism. With the support of the rail 125, the tension provided by the cord 202 can be lowered to take up the slack on the chain with only enough force to provide a more realistic simulation for the user of a shell on the water In some implementations of an exercise machine 100, shown in FIGS , the general location of the rail 126 is higher than in the implementations of FIG. 6. As the rail 126 is attached to the columns 129 and 124 at higher loca tions, the seat 118 can be attached directly to the rail 126. The seat 118 is attached to the rail 126 using sets of wheels in a manner similar to that of the seat 118 of FIG. 6 is attached to the raised rail Referring to FIG. 13, an elastic centering device 250 connected to the seat 118 urges the seat 118 toward a central home location 170 along the rail 126. The elastic centering device 250 can be, for example, a bungee cord. The elastic device 250 is connected at one end 251 near the upper center of a side support 255 on which the seat 118 is mounted. Another end 252 of the elastic device 250 is connected to the frame 129 of the exercise machine 100. The end 252 of the elastic device 250 is connected to an exterior surface of the back Supporting leg 235. In some implementations, the end 252 of the elastic device 250 is connected on the inside of the back Supporting leg 235. In some implementations, the end 252 of the elastic device 250 is connected to the back end 124 of the rail 125. As the seat 118 rides back and forth the bungee cord 250 expands and contracts to apply a modest restoring force to the seat 118 to urge it back towards the center position Other embodiments are within the scope of the fol lowing claims For example, the force transfer mechanism can be supported by a cable connected from above the force transfer mechanism. This cable could be connected on the other end to an element that slides along the top 149 of the rail 125. The force transfer mechanism could also be supported from the sides, by connecting one or both of the two side plates 702, 703 to the side walls 150, 151 of the rail 125using a cable and a slot in the walls 150, 151 of the rail 125. In some imple mentations, the bottom of the force transfer mechanism and the floor of the rail 125 can be magnetized with the same polarity so that the force transfer mechanism and the floor of the rail 125 repel each other In some implementations, the seat 118 could be fixed in place rather than being able to ride back and forth 153 along its Support. What is claimed is: 1. An exercise machine comprising a resistance device connected to a flexible driving line used to drive the resistance device, a flexible exercise line to receive forces applied by the user's hands and feet during cycles of exercising, a force transfer mechanism that couples forces, received on the exercise line from the user during exercising, to the resistance device during the exercise cycles, and moves back and forth relative to a frame of the machine, and a Support along which the force transfer mechanism rides during use of the machine and that Supports the force transfer mechanism vertically. 2. The machine of claim 1 in which the force transfer mechanism slides on the Support. 3. The machine of claim 1 in which the force mechanism rides along a direction corresponding to the directions of the forces applied by the user's hands and feet. 4. The machine of claim 1 in which the Support comprises a rail. 5. The machine of claim 1 in which the support includes a mechanism to reduce friction as the force transfer mechanism rides along the Support. 6. The machine of claim 5 in which the friction reducing mechanism includes a material. 7. The machine of claim 6 in which the material comprises a layer. 8. The machine of claim 7 in which the layer lies between the force transfer mechanism and the Support. 9. The machine of claim 1 in which the support includes a mechanism to reduce noise from the movement of the force transfer mechanism on the Support.

20 US 2012/ A1 Apr. 26, The machine of claim 9 in which the noise reducing mechanism includes a material. 11. The machine of claim 10 in which the material com prises a layer. 12. The machine of claim 11 in which the layer lies between the Support and a layer of a friction reducing mate rial. 13. The machine of claim 1 in which the support is posi tioned below a rail connected to a seat for the user and a foot rest assembly that receives the force applied by the user's feet. 14. The machine of claim 13 in which one end of the Support and the rail are attached to a structural element and the other end of the support and the rail are attached to the resistance device to constitute a frame for the machine. 15. The machine of claim 1 in which the force transfer mechanism has at least one side piece having a bearing Sur face that rides on the Support. 16. The machine of claim 1 in which the force transfer mechanism is connected to a resilient flexible line. 17. The machine of claim 16 in which the resilient flexible line applies a force on the force transfer mechanism to take up slack in the flexible exercise line during parts of the exercise cycle when the user is applying less force than other parts of the exercise cycle. 18. The machine of claim 17 in which the force applied by the resilient flexible line is as low as 3 pounds. 19. An exercise machine comprising a resistance device connected to a flexible driving line used to drive the device, a flexible exercise line to receive forces applied by the user's hands and feet during cycles of exercising, a force transfer mechanism in which pulleys couple forces, received on the exercise line from the user during exer cising, to the resistance device during the exercise cycles, the force transfer mechanism having a bearing Surface that slides back and forth along, and is Supported Vertically by, a Support on a frame of the machine a resilient flexible line that applies a force on the force transfer mechanism to take up slack in the flexible exer cise line during parts of the exercise cycle when the user is applying less force than during other parts of the exercise cycle, and a rail connected to a seat and a foot rest assembly, the rail positioned above the Support. 20. A method comprising in an exercise machine, driving a resistance device using a flexible driving line, receiving forces applied by the user's hands and feet during cycles of exercise, on a flexible exercise line, using a force transfer mechanism, coupling forces received on the exercise line from the user during exercising to the resistance device during exercising, in addition to forces applied from the flexible driving line and the flexible exercise line, applying an upward Vertical force on the force transfer mechanism during use of the machine. c c c c c