Exercise device and method

Abstract

An exercise device includes an upper frame supporting a seat back, the seat back enabling support of a torso of a user. A lower seat includes a lower frame that is pivotally mounted to the upper frame. The lower frame includes front and rear support wheels for contact with a supportive surface; and an arcuate member is secured to the upper frame substantially opposite to the seat back. The device also includes a tension arm with a first end movably mounted to the upper frame and a second end movably supported on the supportive surface by a roller or wheel. A tension band is mounted at one end to the tension arm between the first and second ends of the tension arm and at its opposite end to the lower frame by an anchor bar, which is pivotally mounted to the lower frame.

Description

FIELD OF THE INVENTION

The present invention generally relates to exercise equipment. More specifically, the present invention relates to light weight systems of physical exercise that stress the extensor muscles of the lower body and trunk.

BACKGROUND OF THE INVENTION

Exercise devices are becoming an increasingly more important part of our lives. As our society becomes more technologically advanced, we become more sedentary. Therefore we must rely on equipment to provide our muscles and organs with the stimulation necessary to maintain a healthy existence. Much of the equipment available is large, inexpensive and not practical for the average consumer to have in their home. Gyms and health clubs are not available to many people, especially in rural areas. In addition, with our busy lives, many simply do not have time to drive to the gym to exercise and return to home or work. As an alternative, home fitness products are inexpensive, lightweight products that offer an alternative to the traditional iron. These products must be functional, versatile and inexpensive to obtain and maintain.

Weight loss is a key issue with most Americans. As such, a useful product must exercise the larger muscles in the body, specifically the extensor muscles of the hips and legs. These are the most powerful muscles in the body and can therefore do the most work. Increased work done by the body is extra energy expended. Therefore given a constant dietary intake this results in weight loss. In order for this to happen, the product must be used. A product that is too large and bulky, or where the user must sit on the ground to use it, is not found to be popular with the typical consumer. They like to be in a chair-like device, off the floor, where they can perform perform the exercises and when finished, pick the machine up and roll or carry it away.

SUMMARY OF THE INVENTION

In one aspect, the invention features an exercise device with an upper frame supporting a seat back, the seat back enabling support of at least a portion of a torso of a user. A lower seat includes a lower frame that is movably or preferably, pivotally mounted to the upper frame. The lower frame includes a front support and a rear support for contact with a supportive surface (the floor); and an arcuate member secured to the upper frame substantially opposite to the seat back. When a force is exerted on the seat back toward the arcuate member, the upper frame translates up and back, rolling on the arcuate member while the front support remains in contact with the supportive surface and the rear support is elevated from the supportive surface.

A tension arm may be included that has a first end movably mounted to the upper frame and a second end movably supported on the supportive surface. This movable support is preferably by use of a rolling element such as a wheel, bushing roller and a ball bearing. A tension band is preferably used in conjunction with the tension arm. It is releaseably mounted to the tension arm, optimally between the first and second ends of the tension arm by use of a band receiver, and also to the lower frame. A spring clip may be used to releaseably secure the tension band to the tension arm. The tension band may be attached to the lower frame by way of an anchor bar, which is optimally pivotally mounted.

Handles may be mounted to the upper frame adjacent to the lower frame. In addition, a set of upper handles may be mounted to the upper frame, a distal end of said upper handles positioned adjacent the head of a user as they would be positioned on the device. A headrest may be included that is adjustably mounted to the upper frame.

An exercise device will optimally include a pair of arcuate members spaced adjacent to one another and positioned such that there is a greater distance between the arcuate members father away from the upper frame relative to nearer the upper frame. The device may include a plate receiver mounted to the upper frame, thus enabling weight plates to be received thereon. This plate receiver is optimally positioned near the lower frame and most importantly positioned on a portion of the device that includes vertical movement during an exercise. A cover comprised of a high friction material is optimally placed on the arcuate members to insure a high frictional force between the supportive surface and the arcuate member.

In another aspect, the invention includes a method of exercising including providing a device as previously disclosed and seating a user on the lower seat with the back of the user against the seat back. The user extends his legs and hip joints, pushing the seat back toward the arcuate member, rolling back on the arcuate member and elevating a lower portion of the upper frame while extending the body of the user. If a tension arm is provided, the method may include displacing the tension arm and elongating the tension band, thereby increasing work done by the user.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects of this invention, the various features thereof, as well as the invention itself, may be more fully understood from the following description, when read together with the accompanying drawings, described:

FIG. 1 is a front isometric view of a body extension exercise machine, the device produced in accordance with the present invention.

FIG. 2 is a rear isometric view of a body extension exercise machine, the device produced in accordance with the present invention.

FIG. 3 is a partially exploded, front isometric view of a body extension exercise machine with the seat back and lower seats separated, the device produced in accordance with the present invention.

FIG. 4 is a side view of a body extension exercise machine shown in a starting position, the user with one hand on a lower handle and the other hand on an upper handle, the device produced in accordance with the present invention.

FIG. 5 is a side view of a body extension exercise machine shown in a final or extended position, the user with one hand on a lower handle and the other hand on an upper handle, the device produced in accordance with the present invention.

FIG. 6 is a front isometric view of a body extension exercise machine shown in the extended or final position and with the seat back displaced, the device produced in accordance with the present invention.

FIG. 7 is a plan view of a body extension exercise machine illustrating the angled orientation of the arcuate members, the device produced in accordance with the present invention.

FIG. 8 is a front isometric, exploded view of a body extension exercise machine shown in its starting position and including two pair of clips to secure the tension bands, the device produced in accordance with the present invention.

FIG. 9 is a front isometric view of a body extension exercise machine shown in its starting position with plate receivers and weight plates added on one side and exploded on the other side, the device produced in accordance with the present invention.

FIG. 10 is a front isometric view of a body extension exercise machine shown in its starting position with plate receivers and weight plates added on both sides and without a tension bar behind the seat, the device produced in accordance with the present invention.

For the most part, and as will be apparent when referring to the figures, when an item is used unchanged in more than one figure, it is identified by the same alphanumeric reference indicator in all figures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is an exercise device that enables a body extension movement and is convertible to a flat bench for multiple exercises. The basic version of the device 12 is shown in FIG. 1 in the form of the preferred embodiment of the invention. The device 12 includes a seat back 14 and a lower seat 16 for supporting a user in a seated position, similar to a chair. A pair of arcuate members 18 is positioned behind the seat back 14 to provide for articulating stable support when the device 12 is rolled back. In this view only one member 18 is seen, and only one member is necessary in order that the device be functional. For increased stability, a pair of members 18 is optimally used. This will become more evident further in the disclosure. The rearward movement constitutes the basis for the majority of the exercises that are performed on the device 12. To assist in this movement, two sets of handles are provided. The first set is the lower handles 20 that are mounted to the frame of the device 12 near the back of the lower seat 16. The user, when seated in the device 12, can extend his arms down, grasp the handles 20 and offer a stabilizing reaction to sliding up and off of the seat back 14 during the extension exercise. The second or upper handles 22 offer an alternative support during the basic exercise in that the arms of the user are raised and “push” to secure his body. This alternative positioning of the body stresses the deltoid muscles and triceps rather than the biceps and forearms when using the lower handles 20. Subtle variations such as this offer a key versatility to the capabilities and therefore the success of the product. The upper handles 22 have another function in that the device 12 can be fully extended back on the arcuate members 1o creating a bench. The upper handles 22 are then positioned to provide stability to allow abdominal exercises to be performed. Arcuate members 18 each have one end connected to upper frame 30 via transverse stub extensions (not numbered) and effectively form extensions of the lower ends of upper handles 22. The upper ends of the arcuate members 18 can also attach to the frame substantially orthogonal to the lower ends of the upper handles 22. The opposite ends of arcuate member 18 are connected to lower frame member 34 or handles 20.

Another key element in this version of the invention is also shown here. A tension arm 24 is movably mounted to the device 12 behind the seat back 14. This arm 24 is supported by a support 26, preferably in the form of a wheel or roller as shown here. The support 26 is supported on the floor on which the device 12 sits and translates away from the seat back 14 as the device 12 rolls back on the arcuate members 18. When this happens the tension bands 28 elongate, thus work is done. Different tension bands 28 can be used for varying the resistance. For example, the different tension bands 28 can be made thicker, of different materials, etc.

In FIG. 2 the device 12 is shown from the rear, thereby illustrating the structural elements in this the preferred embodiment. An upper frame 30 provides the structural support for the seat back 14, the arcuate members 18, lower handles 20, upper handles 22 and a first end of the tension arm 24. The tension arm 24 is pivotally mounted to the upper frame 30 by way of a clevis 32. The second key frame element is the lower frame 34. The lower frame 34 provides a secure mounting surface for the lower seat 16 and provides a base mount for the tension bands 28. Optimally, two tension bands 28 are used, as is shown here, that are mounted between the tension arm 24 and the lower frame 34. In this position, the device 12 is at “rest” and therefore the tension bands 28 are not extended significantly beyond their resting length. At the second end of the tension arm 24, two supports 26 are provided. As previously noted, these are intended to move or translate along the floor or other supportive surface. Here, two supports 26 are used. This is not necessary for the function of the device 12 in that a single support 26 or roller could be used. Two supports 26 are used to offer greater stability to the arm 24 and the device 12 when in use.

Another aspect of the invention illustrated here is an adjustable headrest 36. The headrest 36 is comprised of a head pad 38 and a male post 40. The male post 40 is telescopically received by the upper frame 30 and secured in a desired position by placement of a pin in one of the tube holes 42, which is received in a corresponding one of a plurality of spaced apart holes (not shown) in male post 40. Additional holes 44 are used to secure the seat back 14 to the upper frame 30. The versatility of the movable headrest 36 is another advantage to more adequately fit a variety of physical types of users.

Another view of this embodiment is shown in FIG. 3. Here the seat back 14 and lower seat 16 have been separated to show the structure of the device 12. Of specific interest in this view is the lower frame 34. The lower frame 34 is pivotally mounted to the upper frame 30. When in this position the bottom portions of the arcuate members 18 are in contact with the floor as well as the supports 26. In this, the starting position of the exercise, the lower seat 16 must substantially support the body weight of the user. This load is transferred to the lower frame 34, which must be supported by the floor on which the device 12 sits. For that, the lower frame 34 must also have supports. The upper frame 30 is supported from behind by the arcuate members 18. The upper frame 30 is pivotally mounted to the lower frame 34, which includes front supports 46. Without a rear support 48, the area of pivotal connection of the upper frame 30 and the lower frame 34 would hit the floor. As the exercise is performed, with the weight of the user on the device 12, the initial movement of this pivotal connection area would drag on the floor until enough vertical displacement was achieved. By rolling back on the arcuate members 18, the lower frame must be horizontally displaced. Because of that, the preferred embodiment of the front supports 46 and the rear support 48 are wheels or rollers. A slider or pad with a low coefficient of friction could be used, but a rolling element is preferred. This eliminates any damage to the floor by the device 12 scratching along the initial movement of the exercise.

The tension bands 28 are mounted between the tension arm 24 and the lower frame 34. The lower frame 34 acts as an anchor to provide a reaction force to the tension applied by the tension bands 28 when they are stretched due to the displacement of the tension arm 24 when in an extended (rolled back) position. To aid in the alignment of the tension bands 28 with minimal axial slippage and associated wear, an anchor bar 50 is provided. The anchor bar 50 is pivotally mounted to the lower frame 34 and therefore acts as an extension of the lower frame 34. The anchor bar includes a band receiver 52 in the form of a rod that accepts the end of the band 28. The anchor bar 50 is shown here to be pivotally mounted to the lower frame 34 at the axis of the wheel, which is the rear support 48. This is a design choice and considered to be the preferred embodiment, but that precise location of the mounting of the anchor bar 50 to the lower frame 34 is not considered critical to the invention. The ability of the anchor bar 50 to move or pivot relative to the lower frame 34 is of value in that as the device 12 is extended backward, the positions of the tension bar 24 relative to the lower frame 34 and relative to the upper frame 30 both change. The rotational displacement of the lower frame 34 relative to the band 28 can be great. When the band 28 is under tension this load produces a great deal of friction on the band receiver 52. The band 28 is traditionally a molded rubber bar, with holes to receive the band receiver 52. This is not a good bearing surface. A better bearing can be provided in the pivotal attachment of the anchor bar 50 to the lower frame 34, thus reducing wear on the band 28, increasing its functional life and reducing its likelihood to inadvertently come off during the exercise session. Also regarding safety, a cover 53 comprised of a high friction material is optimally placed on the arcuate members 18 to insure a high frictional force between the supportive surface and the arcuate member. This reduces the likelihood of the device 12 slipping when used and makes it reduce noise and potential damage to the floor.

The starting position of the device 12 is shown in FIG. 4, from the side with a user 54 positioned on the device 12. The user 54 is seated on the lower seat 16 and for illustration sake is shown grasping a lower handle 20 with his left hand and an upper handle 22 with his right hand. The user 54 has his back positioned against the seat back 14 and his feet 56 on the floor in front of the device 12.

The final position is shown in FIG. 5 where the user 54 has extended his leg 58 and hip joints, pushing against the floor, with the feet 56 relatively stationary, pushing the seat back 14 back on the arcuate members 18. This results in rolling the device 12 back on the arcuate members 18 raising the rear support 48 of the lower frame 34 off the floor. At this degree of rearward extension, the user 54 may be raised off the lower seat 16. The front support 46 maintains contact with the floor in that it is pivotally mounted to the upper frame 30. This allows the user to fully extend his hips and legs without being physically inhibited by any aspect of the device 12. If the device 12 were extended further, depending upon the subtleties of the pivotal connection of the lower frame 34 to the upper frame 30, a limit of the angular displacement can be built in. In this case the front support 46 would eventually be raised off the floor. This provides more work done by the user in that this seat 16 structure has weight and is being vertically displaced. As long as the lower seat 16 and the seat back 14 can become substantially coplanar, there is little potential for the lower seat 16 to interfere with the movement of the legs 58 of the user 54 and therefore can reach a range limiting stop relative to the seat back 14. The angular displacement of the tension arm 24 is also illustrated here. In FIG. 4 the angle between the upper frame 30 and the tension arm 24 is noted by the angle α. When extended, as in FIG. 5, the new angle α₁ is visibly greater than the acute angle α. This angular displacement results in an increased length of the tension bands 28 between these two figures. The tension band 28 is a tension producing spring that when elongated applies a force that opposes this elongation. Thus, work is done by the user to elongate the tension bands 28. The user pushing against the seat back 14, stabilized by the lower handle 20, pushing on the upper handle 22 or any combination thereof, does this work.

The device 12 is shown in the elongated or extended position in FIG. 6 with the seat back 14 displaced to better view the elongated bands 28 and the function of the anchor bar 50. As the tension arm 24 is displaced rearward and the device 12 rolls onto the arcuate members 18, the angle between the lower seat 16 and the tension band 28 changes dramatically. The angular displacement of the tension band 28 relative to the lower seat 16 is roughly twice that of the angular displacement of the band 28 relative to the tension arm 24. The tension band 28 is an elastic element, as previously note and preferably made of a natural or synthetic rubber material. These materials typically have a high coefficient of friction with smooth steel. The band receivers 52 are typically smooth steel. Therefore, continuous rotation under tension can create a great deal of wear. The applicants have overcome this issue by using an anchor bar 50 that is pivotally mounted to the lower frame 34. This moving anchor bar 50 enables virtually no angular rotation of the band 28 on the band receiver 52 of the anchor bar 50, which acts as a part of the lower frame 34. This greatly increases the life of the bands 28 when used on the device 12.

Shipping size is another issue to home fitness products. In many cases it is desirable for the product to ship in a “knocked down” state requiring some assembly by the user. The value of the knock down products as to the shipping costs is greatly reduced, which can be passed on to the consumer as a lower sale price. In doing this, it is desirable to design the components so that they take up a minimal amount of carton size without compromising the function of the product.

Stability of the device while in use is always an issue of concern. The base must be wide enough to allow for normal side-to-side forces without tipping the device over. This is ever apparent when getting on to or exiting the device. The applicants addressed this issue in several ways. A top or plan view of the device 12 is shown in FIG. 7. Here the lower seat 16 is quite apparent in this view along with the upper handles 22 and the lower handles 20. The tension bar 24 extends from the back of the device 12 with the tension bands 28 in place as previously disclosed. Two unique features are apparent in this view. First, the arcuate members 18 are cantered or flared to the outside. This is done to increase the width of the contact points of the arcuate members 18 with the floor while maintaining a minimal sized frame structure to support the members 18.

The second feature is the width of the supports 26 on the tension bar 24. These supports 26 are purposefully positioned to add to the stability of the device, both in a starting position (as when entering and exiting the device 12) and in an extended position as when being used. This support width also aids in stability in case only one of the tension bands 28 would be used. The eccentric load on the frame members would be decreased by the increased width of the supports 26 on the floor.

A partially exploded view of the device 12 is shown in FIG. 8. This better illustrates the knock down capability of the device 12. It is not necessary that the consumer assembles all components, and in most cases it is preferable not to do so. This does give the manufacturer the assembly options. In addition, this view illustrates one example of the manufacturability of this device 12. The elements are as previously disclosed, with the exception of two sets of clips 60. These clips 60 can take a variety of physical forms but have been determined by the applicant to preferably be a form of a torsion spring. The clips 60 can be provided in pairs, as shown here and connected by a tether 62. This can connect an upper to a lower clip 60, as shown here, or a right to a left clip 60. The tether 62 is not critical to the function of the device 12, but only added as prevention against losing the clips 60. The function of the clips 60 is to be received by the band receivers 52 on the outside of the bands 28. The clips 60 apply a frictional force to the band receiver 52 to releaseably secure the band 28 on the band receivers 52. This prevents the inadvertent dislodging of a band 28. This could be especially detrimental when the device 12 is extended and the bands 28 are under tension.

An alternative to the preferred embodiment is shown in FIG. 9. In this embodiment, the lower portion of the upper frame, or the bases of the handles 20 are fitted with plate receivers 64. The plate receivers 64 enable receiving weight plates 66. These plates 66 are shown here in two different sizes, or weights. The amount and combination would be completely up to the user and the structural capability of the weighted device 68. The weight plates 66 are shown to be in position on the device 68 on the rear side and exploded on the far side. The purpose of the weights 66 is to provide additional weight for additional resistance during the exercise. As was illustrated in FIG. 5, this lower portion of the upper frame is elevated during the extension exercise. Therefore, adding additional weight would increase the work done by the user, and therefore the load on the muscles of the user. The tension bands 28 on the tension arm 24 can still be used in this embodiment of the invention.

A second alternative to the preferred embodiment is shown in FIG. 10. As previously disclosed, the presence of the weight plates 66 on the plate receivers 64 provides additional resistance to the muscles of the user performing the exercise. In light of that, it is possible to add enough resistance though weight plates 66 to substitute for the previously disclosed tension arm 24 and tension bands 28. This embodiment illustrates this version of the device 70 without the tension producing elements of the tension arm 24 and tension bands 28. The general function of the device 70 would be identical to that as previously disclosed only with the noted parts being absent.

Claims

1. An exercise device comprising:

an upper frame;

a lower frame movably mounted to the upper frame and including a front support and a rear support adapted to contact a supportive surface;

a seat back secured to the upper frame;

a lower seat secured to the lower frame; and

an arcuate member mounted to said upper frame substantially opposite to said seat back to permit rolling of said exercise device on said arcuate member when a force is exerted on said seat back in a direction toward said arcuate member, whereupon said rear support is elevated from the supportive surface.

2. An exercise device as in claim 1, further comprising a tension arm with a first end movably mounted to said upper frame and a second end adapted to be movably supported on said supportive surface.

3. An exercise device as in claim 2, wherein said second end is adapted to be movably supported on the supportive surface by use of a rolling element.

4. An exercise device as in claim 3, wherein said rolling element includes a roller selected from the group consisting of a wheel, a bushing roller and a ball bearing.

5. An exercise device as in claim 2, further comprising a tension band releaseably mounted between said tension arm and said lower frame.

6. An exercise device as in claim 5, further comprising an anchor bar pivotally mounted to said lower frame, for mounting said tension band to said lower frame.

7. An exercise device as in claim 6, wherein said anchor bar includes a band receiver adapted to receive one end of said tension band.

8. An exercise device as in claim 5, wherein said tension band is releaseably mounted to said tension arm at a position between said first end and said second end of said tension arm.

9. An exercise device as in claim 5, further comprising a band receiver for mounting said tension band to said tension arm.

10. An exercise device as in claim 5, further comprising a spring clip used to releaseably secure said tension band to said tension arm.

11. An exercise device as in claim 1, further comprising a set of lower handles mounted to said upper frame adjacent to said lower frame.

12. An exercise device as in claim 1, further comprising a set of upper handles mounted to said upper frame, distal ends of said upper handles positioned adjacent the head of the user positioned on the device.

13. An exercise device as in claim 1, further comprising a headrest adjustably mounted to said upper frame.

14. An exercise device as in claim 1, wherein said arcuate member includes a pair of arcuate members spaced adjacent to one another and positioned such that there is a greater distance between the arcuate members farther away from said upper frame relative to nearer said upper frame.

15. An exercise device as in claim 1, further comprising a plate receiver mounted to said upper frame for enabling weight plates to be received thereon.

16. An exercise device as in claim 1, further comprising a plate receiver mounted on said device and positioned near said lower frame.

17. An exercise device as in claim 1, further comprising a plate receiver positioned on a portion of said device that vertically moves during an exercise.

18. An exercise device as in claim 1, further comprising a cover on a portion of said arcuate member, for providing a high friction contact between the supportive surface and said arcuate member.

19. An exercise device comprising:

an upper frame supporting a seat back, the seat back enabling support of at least a portion of a torso of a user;

a lower frame supporting a lower seat, the lower frame being pivotally mounted to said upper frame and including a front support and a rear support adapted to contact a supportive surface; and

an arcuate member secured to said upper frame substantially opposite to said seat back to permit rolling of said exercise device on said arcuate member when a force is exerted on said seat back in a direction toward said arcuate member, whereupon said front support remains in contact with the supportive surface.

20. An exercise device as in claim 19, further comprising a tension arm with a first end movably mounted to said upper frame and a second end adapted to be movably supported on said supportive surface.

21. An exercise device as in claim 20, wherein said second end is adapted to be movably supported on the supportive surface by use of a rolling element.

22. An exercise device as in claim 20, further comprising a tension band releaseably mounted between said tension arm and said lower frame.

23. An exercise device as in claim 22, further comprising an anchor bar pivotally mounted to said lower frame, for mounting said tension band to said lower frame.

24. An exercise device as in claim 23, wherein said anchor bar includes a band receiver adapted to receive one end of said tension band.

25. An exercise device as in claim 22, further comprising a band receiver for mounting said tension band to said tension arm at a position between said first end and said second end of said tension arm.

26. An exercise device as in claim 22, further comprising a spring clip used to releaseably secure said tension band to said tension arm.

27. An exercise device as in claim 19, further comprising a set of lower handles mounted to said upper frame adjacent to said lower frame.

28. An exercise device as in claim 19, further comprising a set of upper handles mounted to said upper frame, distal ends of said upper handles positioned adjacent the head of the user positioned on the device.

29. An exercise device as in claim 19, further comprising a headrest adjustably mounted to said upper frame.

30. An exercise device as in claim 19, wherein said arcuate member includes a pair of arcuate members spaced adjacent to one another and positioned such that there is a greater distance between the arcuate members farther away from said upper frame relative to nearer said upper frame.

31. An exercise device as in claim 19, further comprising a plate receiver mounted to said upper frame for enabling weight plates to be received thereon.

32. An exercise device as in claim 19, further comprising a plate receiver mounted on said device and positioned near said lower frame.

33. An exercise device as in claim 19, further comprising a plate receiver positioned on a portion of said device that vertically moves during an exercise.

34. An exercise device as in claim 19, further comprising a cover on a portion of said arcuate member, for providing a high friction contact between the supportive surface and said arcuate member.

35. For use with an exercise device including an upper frame and a lower frame movably mounted to one another, the upper frame having a seat back secured thereto, and the lower frame having a lower seat secured thereto, the lower frame including a front support and a rear support adapted to contact a supportive surface; and an arcuate member mounted to said upper frame substantially opposite to said seat back, an exercise method comprising the steps of:

seating a user on said lower seat with the back of the user against the seat back;

extending the legs and hip joints of the user, thereby pushing said seat back in a direction toward said arcuate member; and

rolling back on said arcuate member and elevating a lower portion of said upper frame while extending the body of the user.

36. A method as in claim 35, wherein said device further includes a tension arm with a first end movably mounted to said upper frame and a second end movably supported on said supportive surface and a tension band releaseably mounted between said tension arm and said lower frame, said method further including the step of:

displacing said tension arm and elongating said tension band, thereby increasing work done by the user.