DE29609009U1 - Underwater exercise device - Google Patents

Description

1G-76 093

Underwater exercise equipment

The invention relates to exercise devices and in particular to exercise devices which are immersed in a liquid and which use the resistance of the liquid. Underwater exercise devices in which the user uses the resistance forces of a liquid such as water are well known.

Underwater exercise is becoming more and more preferred because the forces generated during exercise are generally uniform and not shock-like. In addition, aquatic therapies are preferred where the user has limited strength or balance, is particularly frail or is in a condition where warm water is also therapeutic.

Although known underwater exercise devices and machines function satisfactorily, each device or machine is generally designed as a stand-alone unit that provides only a single exercise for the user. However, in most exercise programs it is desirable that different muscle groups be exercised and it is also desirable that the strength of the different muscle groups be maintained in a preferred proportional balance. For this reason, a comprehensive exercise program requires several different exercises. However, since the known underwater exercise devices and machines are limited to one exercise or several closely related

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While standing exercises are limited, a more comprehensive exercise program requires several different devices and machines. The need to use several different independent devices and machines has the disadvantage that a suitably large water basin is also required to accommodate these different pieces of equipment. Alternatively, with a small water basin, the different pieces of equipment must be craned in and out of the basin and stored or parked when not in use.

The invention provides a universal underwater training machine which does not have the disadvantages explained above and offers underwater training possibilities which were previously neither possible nor known.

The universal underwater exercise machine according to the invention comprises numerous underwater exercise devices operatively connected to one another on a single base or frame.

The universal underwater exercise machine according to the invention allows a user to exercise all of his joints in rotational or reciprocating movements with a single device, whether sitting, standing or lying down.

The universal underwater exercise machine of the present invention is highly modular and numerous exercise devices can be easily added or removed from the base or frame.

The underwater training machine according to the invention has a relatively small footprint and many

Different exercises can be performed in a relatively small pool of water.

The universal exercise machine of the present invention is particularly useful in situations where a comprehensive underwater exercise program is desired, but the size of the pool is to be minimized or it is necessary to reduce the space available for the exercise device in a pool.

These and other objects and advantages of the invention will become more apparent from the following detailed description with reference to the accompanying drawings.

Figure 1 is a perspective view of a universal underwater exercise device embodying the principles of the present invention.

Fig. 2 is a section along the line 2-2 in Fig.

Fig. 3 is a rear view of the two rotation exercisers at one end of the universal underwater exerciser.

Fig. 3A is an enlarged view of the circled portion in Fig. 3 showing the coupling connecting the supports of the frame structure.

Fig. 4 is a section taken along line 4-4 in Fig. 3 and shows a pedal used on the rotation exercise device.

Fig. 5 is an exploded view of the underwater leg exerciser portion at the other end of the universal underwater exercise device.

Figure 6 is a perspective view of a mesh treadmill that may be used with the universal underwater exercise device, as well as an alternative embodiment of the treadmill.

As shown in Fig. 1, the universal underwater exercise machine 30 is placed in a pool 32 filled with a liquid 34, preferably water. The height of the water 34 relative to the machine 30 can be varied and depends on the type of exercise being performed and the capabilities of the person using the machine 30. For proper use of the machine 30, the water level must cover the resistance elements of the exercise device being used. The machine is supported by a submerged machine structure 36 which stands on a bottom surface of the pool 32 and includes a base 38, a first frame structure 40 and a second frame structure 42. The base 38 includes a support or weight bearing member 43 having an upper surface 44 preferably made of a low friction material such as polypropylene, ultra high molecular weight polyethylene ("UHMW PE"), polyvinyl chloride ("PVC"), etc. Slidingly mounted on the surface 44 are a pair of skis 46 having foot supports 48 and resistance members 50 having a surface 52 providing resistance to movement of the skis in their longitudinal direction through the water 34. The skis 46 preferably have a lower surface having a low friction coefficient so that they can easily slide on the surface 44 through the water 34.

The base 38 has side rails 54 which preferably extend above the surface 44. The width of both skis 46 preferably extends the entire distance between the side rails 54 so that the outer edges 56 of the skis are directly adjacent to the inward facing opposite sides of the side rails.

54 and slide relative to them. In addition, the opposing inner edges 58 of the skis 46 are directly next to each other and slide relative to each other when the skis are moved in a simulated skiing motion. The skis 46 are therefore self-guiding and automatically remain in their correct orientation and direction while in use.

A first exercise device 60 is pivotally connected to the first frame structure 40. The device 60 includes actuators or pedals 62 and a crank mechanism 64 which, when actuated by a user, moves in a generally circular path. A second exercise device 70 includes second actuators, preferably supports or rods 72, pivotally connected to the first frame structure 40. When actuated by the user, the supports 72 pivot back and forth in a reciprocating motion along arcs extending substantially longitudinally of the base member 38. The supports 72 can be moved individually or together, in the same direction or in opposite directions.

A third exercise device 80 includes actuators 82 and a support structure 84 pivotally attached to the second frame structure 42. When actuated by the user, the actuators or pedals 82 pivot along arcs and move back and forth in a generally vertical direction relative to the upper surface 44 of the base member 38. The actuators 82 and the support structure 84 are mechanically connected to one another so that they always move in opposite directions. The second frame structure 42 also includes generally horizontal support pads 90 on which the user can lean when performing one of the

Exercise devices 62, 80 are used. In addition, the second frame member 42 has a seat 92 that allows the user to use one of the exercise devices 72, 70 in a seated position.

The second frame assembly 42 includes opposed first and second frame members 94, 96. Each of the opposed frame members 94, 96 includes a pair of generally vertical frame members 98 to which generally horizontal frame members 100, 102 are secured. As shown in Figure 2, the horizontal frame member 100 is preferably a solid plastic rod welded to the upper surface near an edge of the seat 92. The ends of the rod 100 are inserted into plastic bearings 104 having an inner diameter sized to receive and conform to the outer diameter of the rod 100. The bearings 104 are preferably made of a UHMW PE plastic and are press fit into the inner diameter of the center webs of the T-couplings 106. The T-couplings 106 have an inner diameter sized to match the outer diameter of the vertical frame members 98, thereby allowing the T-couplings 106 to slide up and down on the vertical frame members 98. A series of holes 108 (Fig. 1) are drilled through the vertical frame members 98 and matching holes 109 are drilled through the T-couplings 106. A fastener, such as a pin or preferably a stainless steel screw 110, is inserted through the holes 108, 109 and a nylon nut 112 is used to secure the screw 110 in place. The seat 92 can thus be adjusted to different vertical heights with respect to the different exercise devices 60, 70, 82.

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The lower surface of the seat 92 rests on the top of the horizontal frame member 102 when in the horizontal position. The horizontal frame member 102 is rigidly connected to T-couplings 114 which also have inner diameters for sliding over the vertical frame members 98. Pins 116 are inserted through holes 118 (Fig. 1) in the T-couplings 114 and holes 120 in the vertical frame members 98 and are secured in this position by nylon nuts 122. The horizontal frame member 102 on which the seat 92 rests when in the horizontal position can thus also be adjusted to different vertical heights. The seat 92 is preferably made of a medium or high density plastic having a specific gravity of less than one. Thus, when the user rises from the seat, the seat 92 and bar 100 pivot within the bearings 104 to an approximately vertical position, as shown in phantom in Figure 2. When the seat is in this position, a strap or loop 124 is wrapped around the vertical frame member 98 to secure the seat 92 in the vertical position. The seat is therefore selectively movable between a horizontal and a vertical position to allow the user to selectively operate the exercise devices 62, 70, 80 in either a seated position or in an upright position from the same location between the vertical frame members 94, 96.

Figures 1, 3 and 4 show the construction of the first exercise device 60, which has actuators and pedals 62 that are rotatably connected to a crank assembly 64. The crank assembly 64 has first and second generally U-shaped members 130, 132. The members 130, 132 have first side legs 134, second side legs 136 and main legs 138. The distal ends 139 of the first side legs 134

have angle pieces 140 that are rotatably connected to the center web 141 of the T-couplings 142 that are slidably mounted on the vertical frame portion 144 of the first frame structure 40. Preferably, the center webs 141 of the T-couplings 142 include bearings (not shown) with inner bearing surfaces similar to the bearings 104 in Fig. 2. The angle pieces 140 on the distal end 139 of the first side legs 134 therefore fit into the bearing inner diameters of these bearings to enable smooth or jerk-free rotation. Additionally, preferably and in a manner similar to that shown in Figure 1, screws or other fasteners 146 extend through aligned holes (not shown) in the T-couplers 142 and holes 143 (Figure 1) of the vertical frame members 144 to retain and secure the exercise device 60 at different vertical heights. The distal ends of the second side legs 136 are connected together so that the second side legs 136 form a substantially straight or linear member.

As shown in Fig. 4, the actuators or pedals 62 are pivotally mounted to the main legs 138 of the generally U-shaped members 130, 132. Each of the actuators 62 includes a hollow mounting tube 148 having an inner diameter sized to receive and pivot with respect to the main leg 138. The tube 148 is welded at a location in the center of the lower surface 150 of the actuator 62.

Accordingly, the actuators 62 pivot about first axes of rotation that run centrally through the main legs 138 and additionally move along a generally circular path with respect to an axis of rotation defined by the center lines of the center webs 141 of the T-couplings 142. A band or loop 152 is attached to the upper surfaces 154 of each

actuator 62. The band 152 may be rigid or flexible and is attached to the actuator 62 by fasteners 156. The surfaces 150, 154 of the actuator 62 act as resistance surfaces and provide resistance to the movement of the elements 62 in the water. In addition, each of the actuators 62 further includes resistance elements 158, 160 welded to one end of the lower surface 150 near the tube 148.

Preferably, the first and second resistive elements are spaced apart from each other and from the lower surface 150 at an angle of about 60 degrees. However, the resistive elements 158, 160 may be connected to the lower surface 150 at any angle in the range of 5 degrees to 85 degrees. The resistance elements 158, 160 are preferably positioned so that an approximately constant force is required to move the actuating elements 62 along their circular path of motion at a constant speed, regardless of the angular position of the elements 62 with respect to the main leg 138. The opposing surfaces 150, 154, the opposing surfaces 162 of the resistance element 158 and the opposing surfaces 164 of the resistance element 160 all function to resist the movement of the actuating element 62 in the water 34.

Referring to Fig. 3, the second actuator 70 includes supports 72 that are rotatably mounted on the first frame structure 40. The supports 72 include generally straight rods 165 that have handles 166 at one end that are designed to be easily grasped by a user. The rods 165 include T-couplings 167 with center bars 168 that engage with center bars 169 of

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second T-couplings 170 attached to the vertical frame members 144 of the first frame structure 40. Referring to Fig. 3A, bearings 171, preferably made of high density plastic, such as UHMW PE, are sized to have a first larger diameter that is press-fitted into the center web 169 of the T-couplings 170. The bearings 171 have a second smaller diameter that has an outer cylindrical bearing surface sized to be slidably received within the inner diameter of the center web 168 of the T-couplings. Fasteners 172, preferably a combination of a stainless steel bolt and nylon nut, extend through the T-couplings 167, the bearings 171 and the T-couplings 170 to hold the center webs 168, 169 in rotatable engagement. Resistance elements 173 are attached to the opposite ends 174 of the rods 165 and extend a substantial length of the rods 165 between the T-couplings 167 and the opposite ends 174 of the rods 165. The T-couplings 167, 170 and the bearings 171 form rotary couplings or pivot points with axes of rotation extending in a direction generally perpendicular to the vertical members 144 of the first frame structure 40. The axes of rotation enable the supports 172 to be moved back and forth or forward and backward along circular arcs that are generally parallel to the longitudinal centerline of the base member 38. The resistance elements 173 have oppositely directed surfaces 175 oriented to be generally perpendicular to the movement of the supports 72 and provide resistance to the movement of the supports 72 in the water 34.

Fig. 5 shows the structure of the third exercise device. The machine structure 3 6 has a rigid, in general and

The second frame assembly 178 comprises a U-shaped frame 176 which is connected to the central webs 177 of T-couplings 178 which are in turn attached to the vertical frame member 98 of the second frame assembly. An axle 179 has a larger diameter at one end 180 which is dimensioned so that it can be pressed into the inner diameter of the central web 171 of a T-coupling 182 which is arranged centrally on the frame 176. The T-coupling 182 is oriented so that the central web 181 extends generally horizontally therefrom. The axle 179 has a second smaller diameter 184 sized to rotatably fit within the inner diameter of the center web 186 of the T-coupling 188 which is generally centrally located on the axle or support member 190. A fastener, such as a bolt 192, passes through the T-coupling 182, the axle 179 and the T-coupling 188 and is secured by a nut 194. The fastener 192 acts to securely hold the support member 190 to the end 184 of the axle 179. The support member 190 is thus rotatably connected to the frame 176 and rotates about a pivot axis 196 which is generally perpendicular to the support member 190 and intersects the length of the support member 190.

A first pedal or actuator 198 has an axle 200 centrally located on and welded to the lower surface of the actuator or pedal 198. The axle 200 has a larger diameter sized to fit a first diameter 202 of a T-coupling 204 rigidly connected to one end of the axle 190. The axle 200 has a second smaller diameter 206 sized to fit a second diameter 208 of the T-coupling 204. A bushing or bearing 210 has an inner diameter that slidably fits over the diameter 206 of the axle 200.

and also an outside diameter that matches the diameter 212 of the T-coupling 204. A ring 214 has an inside diameter that is sized to slide over the diameter 206 of the axle 200. The outside diameter of the ring 214 is larger than the diameter 212 of the T-coupling 204. Therefore, when the ring 214 is welded or otherwise rigidly connected to the end of the axle 200, it causes the axle to be locked in the T-coupling 204. Preferably, the diameters on the axle 200, in the T-coupling 204, and on the sleeve 210 are sized to engage the adjacent diameters in a bearing relationship, thereby providing continuous bearing contact over the length of the axle 200 that is in the T-coupling 204. A second actuator or pedal 216 includes an axle 218 mounted in the T-coupling 220 in a manner identical to that described with respect to the axle 200 and the T-coupling 204. A retaining ring 222 is mounted on the end of the axle 218, holding it in the T-coupling 220. The actuators 198, 216 also include bands or loop members 224 attached to the upper surfaces of the members 198, 216 by means of fasteners 226.

Thus, referring to Fig. 1, the universal underwater exercise machine 30 can easily accommodate users of different sizes and can be used to perform many different exercises. In use, the user first adjusts the height of the seat 92 to a desired height. In addition, the first exercise device 60 is adjusted to a desired height. Users can support themselves by placing their forearms on the supports 90 and placing their feet in the tabs 152 of the actuators 62 of the first exercise device 60. The first exercise is

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performed by the users moving their legs to actuate the elements 62 in a generally circular path. Alternatively, the same exercise can be performed with the user sitting on the seat 92. The first exercise device 60 can also be used in a third manner by the user sitting on the front end 228 of the seat 92 and placing his hands in the tabs 152 of the actuating element 62. The first exercise device 60 is then actuated by the user's arms moving the actuating elements in their generally circular path of movement against the resistance of the water 34.

In a similar manner, users may rest their forearms on the supports 90 and place their feet in the tabs 224 of the actuators 82 and operate the actuators with their legs. In doing so, the actuators 82 move back and forth in a generally vertical reciprocating motion and have generally parallel upper and lower resistance surfaces that are generally parallel to the reciprocating direction. These upper and lower resistance surfaces oppose the movement of the actuators 82 in the water. Alternatively, users may stand in an upright position on the actuators 82 and use their legs to move the elements 82 back and forth. A third exercise may be performed by users sitting on the seat 92 and using their legs to operate the pedals 82 of the exercise device 80.

As previously described, the seat 92 can be moved to a generally vertical position so that the user can be positioned in an upright position between the frame members 94, 96 and adjacent to the vertically disposed

seat 92. For example, users can stand on the top surface 44, grasp the handles 166 of the supports 72 on the exercise device 70, and use their arms to move the supports 72 back and forth in a back and forth motion. Alternatively, users can combine this exercise with the skis by placing their feet in the foot holders 48 of the skis 46 and moving their legs so that the skis slide generally back and forth lengthwise on the top surface 44. Users can also operate the skis 46 alone by holding onto the first frame assembly 40.

There are several alternative embodiments of the universal underwater exercise machine 30 of Fig. 1.

For example, referring to Fig. 6, the top 43 of the base 38, which supports the weight of the user, is rigidly secured along its sides to and between the side rails 54. The top 43 has a flat, smooth upper surface 44. At the ends of the top 43 are non-rotating rounded end pieces which extend between and are rigidly connected to the side rails 54. The end pieces 234 are arranged so that their rounded outer surfaces extend tangentially into a plane which is identical to the upper surface 44 of the top 43.

An endless looped mesh belt 240 is mounted over the top surface 43 and the non-rotating rounded end pieces 234. The belt 240 slides over the top surface 44 of the top surface 43 in response to a user stepping or walking. The side rails extend a predetermined amount over the surface 44 and cause the mesh belt 240 to be guided therebetween. The mesh construction of the belt minimizes the surface area of the belt in contact with the top surface 44. There is therefore

a significantly lower frictional force between the mesh belt 240 and the upper surface 44 than in the case of a solid belt. To further reduce friction, the belt is made of a UHMW plastic material. The endless mesh belt preferably has a diamond-shaped mesh pattern ranging from about 0.26 cm ² (0.04 square inch) to about 6.45 cm ² (1 square inch). The preferred mesh has a mesh pattern of about 2.32 cm ² (0.36 square inch). The mesh fiber preferably has a size ranging from about 0.0254 cm (0.01 inch) to about 0.64 cm (0.25 inch) in diameter, and preferably the mesh diameter is 0.09 cm (0.035 inch).

The mesh belt 240 moves over the upper surface 44 of the top 43 and under the end pieces 234 and below the top 43 and between the side rails 54. To prevent the belt 240 from contacting and dragging the bottom surface of the pool, a cross brace extends between and is connected to the side rails 54. A lower run of the belt is above the cross brace, which keeps the lower run of the mesh belt 240 away from the bottom of the pool. When the user is in the water, the buoyancy force of the user reduces the vertical force exerted on the belt 240, thereby reducing the frictional force between the belt 240 and the upper surface 44 of the top 43. Thus, when a user begins a walking or striding motion, the user applies a force to the belt that has a horizontal component that causes the belt 240 to move in a sliding motion over the upper surface 44 of the top 43. Minimal frictional forces result from the fact that the belt 240 is made of mesh material, which allows for a more consistent stride with little effort. The upper surface 44 of the top 43 is

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made of a hard, strong material that is both smooth and resistant to the corrosive effects of sanitary chemicals added to the water in which the machine is located. Preferably, the top is made of one of a number of medium or high strength plastic materials, a polished stainless steel or some other non-corrosive alloy. The reduced friction also allows the use of non-rotating fixed end pieces 234. The side rails 54 guide the belt and no adjustment mechanism is necessary for this purpose.

In another embodiment shown in Fig. 6, a longitudinally extending divider rail 242 is attached to the upper surface 44 of the top side 43 so that the rail divides the upper surface 44 longitudinally. In this embodiment, two mesh bands 244 and 246 are provided around the top side 43 and between the divider rail 242 and the side rails 54. The mesh bands 244, 246 can be moved independently of each other and in different directions. The two mesh bands 244, 246 can therefore be used to simulate a sliding ski motion, but in which the skis are not required. As further shown in Fig. 6, the band 246 can be made so that the mesh-like, structured lower surface of the surface 44 faces the top side 43. A differently textured non-mesh surface that is denser and, as desired, either rougher or smoother than the mesh surface may be fabricated on the outer surface of the belt 246 on which the user walks.

Although the invention has been explained by a very detailed description of the embodiments,

it is not intended to limit the claims to these details. Additional advantages and modifications will be readily apparent to those skilled in the art. For example, the first and second frame assemblies 40 and 42, respectively (excluding the horizontal frame member 100), the first and second generally U-shaped members 130 and 132, the rods 165, the U-shaped frame member 176, the support member 190, the axle 200, and their associated T-couplings and elbows are preferably made from commercially available PVC pipe materials. However, these assemblies may also be made from stainless steel, a non-corrosive alloy, a composite reinforced hardenable polymer, or any combination of the foregoing materials.

The actuators 62, 82 and the resistance elements 158, 160, 173 can be made of any rigid flat plastic material and the skis 46 have a lower surface preferably made of a polypropylene or medium or high density polyethylene. Other materials that provide the desired frictional properties and corrosion resistance can also be used.

The skis 46 include resistance elements 50, preferably located at the front ends of the skis. Alternatively, the resistance elements may be located at the rear ends of the skis or resistance elements may be located at both ends of the skis. Skis without any resistance elements may also be used. The mesh band is preferably made of "DELRIN", nylon, high density polyethylene or other high density thermoplastics; however, the mesh band may be made of a curable polymer, a composite reinforced plastic, a thermoplastic elastomer, interlocking metal joints in a mesh pattern or other materials that can be provided with a mesh pattern having a smooth

surface that provide a sufficiently small friction between the mesh belt and the upper surface of the top. The skis can also be used directly on the mesh belt or the mesh belt can be replaced by a piece of mesh-like material that is attached to the support surface over which the skis move. Pieces of mesh material can also be attached to the lower surfaces of the skis so that the skis move slightly with respect to the support surface.

The invention in its broad aspects is therefore not limited to the specific details shown and described. Thus, departures from such details may be made without departing from the spirit and scope of the invention.

Claims (12)

1G-76093 Claims 1. An exercise machine using fluid resistance, comprising: a frame structure (38, 40, 47) which can be immersed in the liquid,- a first exercise device (60) having a pair of actuators rotatably mounted to the frame structure for movement in a generally circular path and capable of being submerged in the liquid, each of the actuators having an upper surface against which a user can press and a lower surface for providing resistance to movement of the actuator in the liquid in response to manipulation by a user; a second exercise device (80) having a pair of actuators pivotally connected to the frame structure and capable of being immersed in the liquid, each of the actuators being reciprocally movable and having an upper surface against which a user can press and a lower surface for providing resistance to movement of the actuator in the liquid in response to user actuation; and a third exercise device (70) having a pair of actuators operably mounted to the frame structure and capable of being immersed in the liquid, the actuators being adapted to be actuated by a user and having surfaces that provide resistance against reciprocating movement of the actuators in the fluid in response to user actuation. 2. An exercise device using fluid resistance, comprising: a frame (47) which can be immersed in the liquid; a support member (84) pivotally connected to the frame for rotation about a first axis of rotation (196) extending from a side of the support member, the first axis of rotation being generally perpendicular to the support member and intersecting a length of the support member; a first actuating member (82, 198) immersible in the liquid and having a surface providing resistance to movement of the first actuating member through the liquid, the first actuating member being rotatably connected to one end of the support member and having a second axis of rotation extending from an opposite side of the support member in a direction substantially parallel to the first axis of rotation; and a second actuating member (82, 216) immersible in the liquid and having a surface providing resistance to movement of the second actuating member through the liquid, the second actuating member being rotatably connected to an opposite end of the support member and having a third axis of rotation extending from the opposite side of the support member in a direction generally parallel to the first and **■ the second axis of rotation, the first and second actuating elements being designed to be alternatively pressured by a user and to move in a reciprocating cycle, the first and second actuating elements moving in opposite directions. 3. Exercise device according to claim 2, further comprising: a first plastic collar (181) extending from the frame; a second plastic collar (186) extending from one side of the support member; an axle (179) having a low coefficient of friction in the fluid with one of the first and second plastic collars, the axle having one end sized to be slidably and rotatably mounted in one of the two plastic collars and the axle having an opposite end sized to fit in the other of the two plastic collars; and a clamping device (192) extending between the first and second plastic collars for holding the first and second plastic collars on the axle. 4. An exercise device according to claim 2, further comprising: a hollow plastic tee (204) having a centrally located main leg connected to one end of the support member in an orientation in which a centerline passing through two tubular side legs of the plastic tee is in the substantially parallel to the first axis of rotation, the plastic T-piece further having a larger inner diameter in the two tubular side legs and a smaller diameter in a tubular passage connecting the two tubular side legs; an axle (200) having an end extending through the two tubular side legs and the tubular passage, the axle having a first larger diameter sized to slidably and rotatably fit the larger inner diameter of one of the two tubular side legs, and a second smaller diameter sized to slidably and rotatably fit the smaller diameter in the tubular passage; a tubular collar (210) having an inner diameter sized to slidably match the second smaller diameter of the axle extending through the other of the two tubular side legs, the collar having an outer diameter sized to slidably match the first larger diameter of the other of the two tubular side legs, the axle and the collar forming a rotatable bearing and a coupling extending through the two tubular side legs and the tubular passage; and a retaining member (214) fixedly connected to one end of the axle and having a larger dimension than the first larger diameter of the other of the two tubular side legs to prevent the axle from being pulled out of the T-piece. 5. An exercise device using a resistance in a liquid, comprising: a frame structure (40) which can be immersed in the liquid; and a first and a second actuator (62) which can be immersed in the liquid and is rotatably connected to the frame structure to move in a generally circular path, wherein both actuators an upper surface (154) against which a user can press, and at least one resistance element (158, 160) having one end connected to a lower surface of a corresponding actuating element and providing resistance to movement of the actuating element. 6. An exercise device according to claim 5, further comprising: two supports (72) , each of which a generally straight rod having a first end that can be grasped by a user, a pivot joint (168, 169, 171) disposed between the first end and a second end of the rod and connecting the rod to the frame structure, the pivot joint enabling the support to pivot about a pivot axis that is approximately perpendicular to the rod; and a surface (173) providing resistance to movement of the support in the liquid. 7. Exercise device according to claim 2 and 5, which also comprises: a base (38); a support element (43) connected to the base and having an upper surface that can be immersed in the liquid, and at least one sliding member (46, 240, 244) immersible in the liquid and attached to the support member, being in sliding contact with the upper surface of the support member in response to forces generated by a user in the liquid. 8. An exercise device using fluid resistance, comprising: a support member (43) having an upper surface that can be immersed in the liquid and serves to support a user; a frame structure (40) which can be immersed in the liquid and has at least one substantially vertical frame part; two supports (72), each of which a generally straight rod (72) having a first end that can be grasped by the user, a pivot joint (168, 169, 171) disposed between the first end and a second end of the rod and connecting the rod to the frame member, the pivot joint enabling the support to rotate about an axis of rotation which is approximately perpendicular to the rod; and a surface (173) providing resistance to movement of the support in the fluid, the surface extending substantially between the pivot and the second end of the rod. 9. An exercise device according to claim 8, further comprising a band device (240) immersed in the liquid and attachable to the support member for moving in sliding contact with the upper surface of the support member in response to forces generated by the user in the liquid, the band device comprising an endless loop-shaped band having a mesh-like structure for reducing friction between the band device and the upper surface of the support member, thereby enabling the user to move the band device with less effort. 10. The exercise device of claim 8, wherein the pivot joint further comprises: a first plastic collar (169) extending in a generally horizontal direction from the frame structure; a second plastic collar (168) extending outwardly from the straight rod in a generally horizontal direction; and an axle (171) having a low coefficient of friction with the first or second plastic collar in the liquid, the axle having an end dimensioned to be displaceable and r · art,* m &igr; • · · 1 &bgr; · is rotatably mounted in one of the two plastic collars, and the axle has an opposite end which is dimensioned to fit into the other of the two plastic collars; and a clamping device (172) extending between the first and second plastic collars for holding the first and second plastic collars on the axle. 11. Exercise device using fluid resistance, comprising: a support member (43) having an upper surface (44) that can be immersed in the liquid; a pair of side members (54) immersible in the liquid and connected to two parallel longitudinal edges of the support member, the two side members having mutually facing, inwardly directed surfaces extending at a predetermined distance above the upper surface; a pair of sliding members (46) which can be immersed in the liquid and have upper and lower surfaces facing away from each other, the upper surface of each of the sliding members being able to receive a user's foot and the lower surface slidingly contacting the upper surface (44) in a reciprocating motion, the two sliding members having longitudinally extending outwardly directed edges (56) immediately adjacent the inwardly directed surfaces of the two side members (54) and opposing longitudinally extending inner edges (58) immediately adjacent to each other to cause the sliding members to be automatically guided and to achieve a desired direction of movement in response to maintain a relative back and forth movement to each other. 12. Exercise device using fluid resistance, comprising: a base element (3 8); Actuators (62) rotatably connected to the base and immersed in the liquid and operable by a user, the actuators having surfaces that provide resistance to movement of the actuators in the liquid; a frame structure (42) connected to the base member and capable of being immersed in the liquid, the frame structure comprising opposing first and second frame members, one of the frame members comprising a support member; and a seat member (92) adapted to support a user in a generally seated posture, the seat being pivotally connected to the support member along one side and being selectively pivotable about a generally horizontal pivot axis between a generally horizontal position and a generally vertical position, thereby enabling the user to operate the actuating elements in a first seated posture between the frame members when the seat is in the generally horizontal position and in a second upright posture between the frame members when the seat is in the generally vertical position.