WO2008139197A1

WO2008139197A1 - Fitness device

Info

Publication number: WO2008139197A1
Application number: PCT/GB2008/001670
Authority: WO
Inventors: Beverley Gove; Nigel Mclean
Original assignee: Zone Fit Limited
Priority date: 2007-05-14
Filing date: 2008-05-14
Publication date: 2008-11-20
Also published as: EP2152374A1; GB0709290D0; GB0715331D0; CA2724134A1; US20100311548A1

Abstract

A portable fitness device is described comprising a frame, and an opening defined by the frame. The device is configured to be placed on a surface such that the opening defines a step area, which may be a part of the surface, and the frame separates the step area from a first region of the surface. The opening is configured to enable a user to step through the opening between the step area and the first region of the surface. In a preferred embodiment the device is height adjustable. Methods of use are also described. The device facilitates a range of exercise routines suitable for individuals with varying levels of fitness.

Description

FITNESS DEVICE

The present invention relates to a fitness device for aerobic exercise. In one particular embodiment, the device comprises a rectangular or square frame which the individual steps in and out of during the aerobic exercise routine. The invention particularly relates to a device for use with aerobic exercise in time with a collection of tailored music tracks and to a routine of pre-choreographed or freestyle steps.

The last 30 years has seen a boom in popularity of aerobic exercise classes with fitness instructors leading a class of individuals ("'fitness students") with a pre-choreographed or freestyle routine. In addition to the freestyle aerobic routines, an alternative aerobic routine was later introduced termed "step aerobics" using a "step" fitness device usually comprising a box-type device with adjustable height typically between 10cm and 30 cm (4 and 12 inches). The step fitness device especially provides an additional strength and/or muscular endurance component to freestyle aerobic routines and is especially effective for additional conditioning of the leg muscles. In addition, the step fitness device localises the fitness student to a particular area of the fitness studio thus allowing the fitness instructor to more easily supplement the routine by occasionally allocating groups of fitness students to different exercises. As step aerobics has become more popular at fitness studios, new designs of step fitness devices have been introduced to facilitate storage of unused steps within the studio (especially by stacking) and to reduce the possibility of injury or wear-and-tear on the joints of fitness students (especially by use of soft plastics with rounded edges and non-slip surfaces).

A disadvantage of current step fitness devices is related to the significant level of injuries to fitness students (and instructors alike) due to impact shocks on joints and tendons, especially whilst mounting the step (particularly knee joints) and dismounting (particularly ankles). In addition, mounting the step has proven difficult to older fitness students and those with limited fitness or limited leg muscle conditioning. There is thus a need for an improved fitness device which allows pre-choreographed and freestyle fitness routines within a localized area but without the risk of injury associated with standard step devices and with a lesser degree of difficulty attractive to older fitness students or those with limited fitness.

It is amongst the aims of the present invention to provide a fitness device with many of the features of available step fitness devices but with a lower risk of injury. A further aim of the invention is to provide a fitness device and exercise routine which is accessible to fitness students of a lower fitness level as well as fully fit individuals.

Further aims and objects of the invention will become apparent from the following description. According to a first aspect of the invention, there is provided a portable fitness device comprising: a frame, and an opening defined by the frame, wherein the device is configured to be placed on a surface such that the opening defines a step area and the frame separates the step area from a first region of the surface, and wherein the opening is configured to enable a user to step through the opening between the step area and the first region of the surface.

The step area may be at a height less than the height to which the frame extends above the surface, and may be a second region of the surface. The surface may be the floor and the device may therefore define a step area on the floor.

The dimensions of the device are adjustable. For example, the length and/or width of the device may be adjustable, and/or the device may be height adjustable. The device may comprise a locking mechanism. The device may have a plurality of discrete height settings, and/or may be adjusted to any height within a predetermined range. The range may be 2cm to 30cm.

In one embodiment, the frame comprises slidable parts which enable the dimensions to be adjusted. Alternatively, or in addition, frame may comprise compressible parts which enable the dimensions to be adjusted. The frame may comprise flexible parts which enable the dimensions to be adjusted. The height of the device may be operable to be adjusted by flexing a component of the frame.

The frame may comprise corners and side parts joining the corners, and the device may be operable to be increased in height by bringing the corners closer together and causing the side parts to flex.

The device may comprise a height adjusting member coupled to the frame, and the height adjusting member may be moveable from a first position in which the frame extends to a first height above the surface, and a second position in which the frame extends to a second height above the surface, the second height being greater than the first height.

The height adjusting member may comprise a support member configured to support a component of the frame in the second position. The height adjusting member may be biased towards the second position.

A locking mechanism may be provided for retaining the height adjusting member in its first and/or second positions. The portable fitness device as claimed in claim X, wherein the locking mechanism comprises a latch, which may be configured for retaining the support member in the first position. Alternatively a magnet, clip or bolt may be provided.

Where a support member is provided, it may be hinged, and a resilient member may bias the support member towards the second position. The support member may be disposed at an edge of the device. Alternatively, the support member may be disposed at a corner of the device.

The frame may comprise corners and side parts joining the corners, and the support member may be disposed on a side part between a pair of corners. The support member may be configured to be placed on the surface. Alternatively, the device comprises a base configured to be placed on the surface, and the support member may be disposed on the base.

Preferably, the device is configured to flex or collapse when stepped on by a user. A downward force on the frame may be operable to reduce the height of the frame. The frame may be configured to flex or collapse from its second position when stepped on by a user. The frame may comprise a plurality of side parts, each side part comprising a base layer and a flexible upper layer disposed over the base layer, and the height of the frame may be adjustable by flexing the upper layer on the base layer.

The height of the frame may be adjustable by bringing opposing ends of the upper layer closer together. Alternatively, or in addition, the opposing ends of the upper layer are fixed relative to respective ends of the base layer, and the height of the frame may be adjustable by changing the relative lengths of the upper layer and the base layer. The height of the frame may be adjustable by reducing the length of the base layer relative to the length of the upper layer.

The portable fitness device may be in the shape of a rectangle or square. Preferably, the portable fitness device rectangular with outer dimensions in the range of 75cm to 150cm along a first axis and 30 to 60cm along a second axis.

The frame may comprise a non-slip surface. The frame may comprise an upper surface of non-slip soft rubber. Alternatively, or in addition, the frame may comprise a non-slip surface on its underside.

The portable fitness device may be configured to be used underwater. The frame may be provided with an attachment mechanism or material for attaching the device to the surface. The frame may comprise a suction surface.

In one embodiment, the step area is a surface of an elevated platform, formed to a height greater than the surface, and less than the height to which the frame extends above the surface. The elevated platform may be formed from an insert to the frame. The insert may be removable from the frame. Alternatively, the elevated platform may be integral with the frame. The elevated platform may have a plurality of sections with different heights, and/or may have a plurality of height settings. The device may be configured to be coupled to a second portable fitness device, which may be a device according to the first aspect of the invention. The portable fitness device may be configured to be stacked with an identical portable fitness device.

The portable fitness device may be configured to be stacked with an identical portable fitness device to create a device of increased frame height.

According to a second aspect of the invention there is provided a portable fitness device comprising a frame defining an opening, wherein the device is configured to be placed on a surface such that the opening defines a first region of the surface and the frame separates the first region from a second region of the surface, and the opening is configured to enable a user to step through the opening between the first and second regions of the surface.

The second aspect of the invention may comprise any of the preferred or optional features of the first aspect of the invention.

According to a third aspect of the invention, there is provided a method of exercising, the method comprising the steps of: a. providing a fitness device on a surface, the fitness device comprising a frame, and an opening defined by the frame; b. stepping through the opening between a step area defined by the opening, and a first region of the surface separated from the step area by the frame.

The step area may be a second region of the surface. The method may comprise the additional step of repeating step b. According to a further aspect of the invention there is provided an aerobic fitness routine comprising instructions for carrying out the method of the third aspect of the invention.

According to a further aspect of the invention there is provided an aquatic aerobic fitness routine comprising instructions for carrying out the method of the third aspect of the invention.

According to a further aspect of the invention there is provided a data storage medium comprising instructions for carrying out the method of the third aspect of the invention. The data storage medium may comprise audio-visual data.

The fitness device may be based on the principle of a "slep-without-a-top" whereby the fitness device requires stepping in and out of a frame whereby typically the step inside the frame results in stepping onto the floor of the fitness studio. The fitness device therefore serves as a focus for the feet of the fitness student.

The invention encompasses a variety of shapes, sizes and heights of device, devices comprising various materials, various aspects of the device which facilitate storage of multiple devices, various additions to device, and various uses of the device.

The device can be of any shape, and in preferred embodiments the device is square or rectangular typically with outer dimensions of 75- 150cm and 30-60cm. Heights of the standard device will typically range from 2-30cm. As an alternative to square and rectangular, the device can have other shapes such as circular, elliptical, triangular, and polyhedral or combinations of various shapes. Adopting different shapes may facilitate useful variations of the device exercise programme(s).

In addition, the devices may be constructed using sliding parts, extendable parts, compressible parts or flexible parts to the frame to provide for adjustable dimensions of length and/or width and/or height. For example, in one embodiment the device incorporates sliding parts or flexing parts in the width dimension allowing a range of widths from 30cm to a maximum of 60cm with the sliding parts fully pulled apart. Such adjustable dimensions can be locked, for example via a system of pins or ratchet system or other locking mechanisms to prevent the sliding parts or flexing parts from moving relative to one another during a fitness routine.

Height, in particular, may be adjustable through the use of "stacking devices'^" whereby, for example, three 5cm high devices can be stacked via complementary grooves in each device or via pins to give a 15cm high device assembly.

In a preferred embodiment the width and length of the device is reduced and the height is increased by pulling or bringing the corners closer together causing the side parts to flex. It will be understood by those skilled in the art that alternate means of extending or reducing the length, width and height of the device are possible.

The devices can be composed of a range of materials and a range of thickness of material. Typically the material within the device frame will be lightweight plastic or soft rubber or a combination of these, typically with non-slip soft rubber at the top of the device frame to avoid or mitigate any problems when the fitness student impacts the frame. Typically the material will consist of a strong and heavy duty, long lasting material that resists deterioration or alteration of the material properties after prolonged and repeated use in the gym or home environment or in the aquatic environment. Such a material may be vulcanized rubber or marine grade rubber, or may be acrylonitrile butadiene styrene plastic or other suitable plastic. An important safety aspect of one embodiment of the device is that if it is stepped on, the device will collapse or flex by virtue of its soft malleable material, or due to a design which causes the sides of the device to collapse or flex. The device may then have the ability to return to the lowest height setting if pressure is put on to the edges or corners of the device. For example, if the user steps on the device, the device will return to the lowest setting and prevent the user from damaging an ankle or falling.

Typically the frame material will be 2-6cm thick. Typically the underside of the frame will be equipped with a non-slip surface and, commonly, with a material which will attach to the floor of the fitness studio such as a suction surface or similar in order to prevent the device frame from tipping upon impact by the fitness student. As an alternative to plastic or rubber, the device frame could consist of a thin inflatable material, or the frame could be hollow to facilitate filling with a heavy weight material.

The device or its components may be formed from one or two moulds: one for the edges or side parts, and one for the corners. The corners or side parts may be formed from two pieces which are reversibly or irreversibly mated together. They may therefore include a Mock and key', or tongue and groove joint to form a complete frame shape.

Certain variations of the device concept form part of the invention. For example, instead of just providing a frame for the fitness student to step into and onto the fitness studio floor, the inside of the frame could contain an elevated platform to a height less than the height of the frame. This could comprise an insert which is placed inside the frame, and which is composed of materials similar to that of the frame, such as non-slip soft plastic or rubber, or alternatively, a material or surface designed to produce a significant bounce or rebound force once impacted by the fitness student. Alternatively, the device frame could be attached to or integral with the elevated platform, which may function to anchor the device frame to prevent tipping. A further variation of the device is a combination with a conventional or modified step device, for example where the device frame is attached adjacent to a step or where the device frame with an elevated platform is attached adjacently to a step. Further variations including two or more segments of elevated platform within the device frame should be considered within the scope of the present invention. IO

Aspects of the device may facilitate storage of multiple devices. For example, the device frame can be constructed with a retractable hook, a hole or some other "catch" to enable the device to be hung onto a hook or pole within the fitness studio storage space. Alternatively, device frames can be constructed with grooves or other protrusions to facilitate stacking. Alternatively, device frames can be constructed with one or more hinges to enable the device frame to be folded prior to storage. In addition, device frames can be constructed with one or more handles, preferably retractable, to facilitate carrying of the device frames.

Various additional features may be included in the device. For example, the device can be constructed with various audio, video jacks or Bluetooth® technology to enable connection with or transmission to devices worn by the fitness student, or to connect or transmit to devices placed adjacent to the device and used by the fitness student. In particular, the device can include a radio receiver to receive audio and/or video transmissions from a central transmitter in the fitness studio, such central transmitter commonly transmitting a music audio track with accompanying microphone transmission from the fitness instructor. In turn, the fitness student may wear a receiver, for example an earpiece or headphones, for receipt of the audio signal from the device. Similarly, outside of the fitness studio, a radio receiver within the device can be synchronised with a video track on a display screen to enable the fitness student to undertake the device routine outside of the fitness studio. Alternative transmissions to the fitness student via the device will include fitness videos/DVDs to accompany the device fitness session, television channels, sources of written information with student controlled access to pages and paragraphs, for example newspapers or books, and other view/Iisten-on- demand forms of entertainment including films, music tracks and sporting events.

Further additions to the device may be a cardiac or pulse monitor, or other physiological or biochemical monitor via one or more probes attached to the fitness student which transmits to a receiver in the device. The receiver can then either display a signal to indicate a physiological or biochemical measurement from the fitness student or can transmit the signal to another receiver. For example, a bank of displays may be provided in front of the fitness instructor thus allowing the instructor to monitor the fitness students. Other types of measurement or outputs which can be undertaken via the device will include blood parameters such as glucose level, a calculation of calories burnt during a fitness session, a calculation of number of steps inside and/or out of the device during a session, flashing lights or other video/audio responses when the student steps into the device, or one or more responses when the device frame is touched during a session.

Where the device has variable dimensions, the device frame could include one or more motors which can be controlled by the fitness student or instructor to modify the dimensions of the device during a fitness session. For example, there may be provided motors which push apart sliding parts of the frame to lengthen one of the dimensions, or pull together corners thus shortening the sides and / or increasing the height.

The device frame may include additional fitness devices, or attachments for the addition of fitness devices. For example, the device frame may be fitted with grooves or hooks for attachment of rubber bands or other extendible materials, which facilitate the inclusion of arm exercises in the device exercise routine(s).

The device is used primarily for fitness studio-based aerobic fitness sessions comprising multiple fitness students and one or more instructors. Alternatively, or in addition, the device may be used by individual fitness students with or without a fitness instructor, and may be used in the home. A further alternative use of the device is in swimming pool- based aerobic fitness sessions, in which the device frame contacts the floor of the pool, and is easily and reversibly secured to the floor for example by suckers or by virtue of its weight. Additional venues for use of the device can be envisaged, including grass surfaces and in the office. A preferred use of the device is in conjunction with an audio and/or video-based fitness programme directed at fitness instructors for their instruction of groups of fitness students. Such a fitness programme will preferably provide training for fitness instructors in the effective instruction of groups of fitness students. This may include identification of deficiencies in the technique of the students, which may be looked for or corrected. Such deficiencies may include poor step technique, poor posture and practices associated with a risk of injury. Such a programme may be delivered through central training workshops for instructors and by theoretical and practical examinations for instructors prior to their certification to instruct groups of fitness students.

It will be understood that the scope of the present invention of the device fitness device should not be interpreted too narrowly and will include other similar devices based on the step-without-a-top principle or any similar device used for stepping in and out of. It is understood that, in addition to the variations and different forms of the present invention described herein, there will be many other variations of the basic invention which should be considered within the scope of the present invention as defined by the claims.

For a better understanding of the invention, embodiments of the present invention are illustrated in the following drawings by way of example only:

Figure 1 is a plan view of a device according to an embodiment of the invention; Figure 2 is a longitudinal-section view of the device of Figure 1 in a low height setting;

Figure 3 is a perspective view of the device of Figure I in a raised height setting; Figures 4A and 4B are longitudinal-section views of a side portion in accordance with an embodiment of the invention in low height and raised height settings respectively;

Figure 5 is a sectional view of a support member in accordance with an embodiment of the invention;

Figure 6 is a longitudinal-section view of a side portion in accordance with an alternative embodiment of the invention a raised height setting; Figure 7 is a sectional view of showing a detail of the base layer of the embodiment of Figure 6;

Figures 8A and 8B are longitudinal-section views of a side portion in accordance with a further embodiment of the invention in low height and raised height settings respectively.

Referring firstly to Figures I and 2, there is shown a portable fitness device in accordance with a first embodiment of the invention, shown generally at 10. The device 10 includes a frame 12 defining an opening 14. The device 10 is shown placed on a floor, and defines a step area 16 through the opening. The frame 12 separates the step area 16 from a first region 18 of the floor. The frame 12 has a substantially rectangular shape, with dimensions of 60 cm by 75 cm. The frame comprises a plurality of side portions 20 which join corners 22. In this embodiment, the corners 22 are rounded. The frame 12 is constructed from a hardwearing, lightweight plastic, and in this embodiment the side portions 20 are provided with a non-slip soft rubber on their upper surfaces. The underside of the device is provided with a non slip material.

In use, the device 10 defines a step area 16 which is separated from a first region of the floor 18. The fitness student or user performs an aerobic exercise routine, which may be a series of pre-choreographed steps, or alternatively maybe freestyle steps. In the configuration shown in Figures 1 and 2, the frame extends to a height of approximately 2 to 6 cm above the floor. In addition, the step area 16 is a second region of the floor, and is therefore the same height as the first region 18 of the floor.

The device IO of Figures I and 2 is height adjustable, and Figure 3 is a perspective view of the device 10 in a second position, where the frame 12 extends to an increased height from the floor. The increase in frame height is provided by upward flexing of the side portions 20, such that they form upstanding bows supported on the floor by corners 22. An individual exercising using the device in its raised height setting experiences an increase in energy expenditure compared with use of the device when set at a lower height, due to the requirement to lift his or her leg higher when stepping over the frame.

Figures 4 to 8 schematically show various mechanisms by which the height adjustment of the frame may be achieved.

Figure 4A is a longitudinal section through a side portion 40 and a pair of corners 42. The side portion 40 is formed from an upper flexible layer 44 and a base layer 46. Opposing ends of the upper layer 44 and the base layer 46 are received in recesses in respective opposing corners 42.

Figure 4B shows the apparatus of Figure 4A in an increased height position. The increased height has been achieved by bringing the ends 48. 50 of the upper flexible portion closer together to upwardly flex the upper layer. The ends are retained in the position shown in Figure 4B by means of corresponding pins and recesses in the corner 42. In the increased height position shown in Figure 4B, the upper layer provides an upstanding bow, which increases the height of the frame and therefore the height over which the fitness student must step in use of the device. The materials and configuration are selected such that the frame is resilient. The frame will flex downward if a fitness student steps on the upper surface of the upper layer, and will return to the increased height position shown in Figure 4B under its own energy.

Figure S shows an alternative configuration 60, in which an additional support member 52 is disposed between the base layer 46 and the upper layer 44. The support member 52 tends to bias the upper layer 44 to the increased height position. In order to retain the device in a low height setting, a retaining mechanism (not shown), such as corresponding pins and recesses in the corners 42, is provided. The biasing force of the support member 52 can be overcome by a downward force on the frame.

Figure 6 is a longitudinal section through an alternative arrangement 62, in which the base layer 66 is fixed relative to the flexible upper layer 64 and the corners 42 at its ends. The base layer 66 telescopically retracts to move the ends of the upper layer 64 together such that the upper layer flexes. If the device stepped on when in its increased height position, the upper layer 64 can flex by virtue of its material properties. The spring 68 may be extended due to the downward force, before returning to its contracted state and causing 64 to return to its raised height, bowed position. The side portion of the device is therefore resilient.

Figure 7 shows an internal detail of the base layer 66, including a spring which biases the base layer towards a retracted position. The device 62 may be retained in a flat arrangement (similar to that shown in Figure I and Figure 4A) by any suitable locking mechanism. A further alternative is shown in Figures 8A and 8B. In this embodiment, the device 80 includes a pair of support members 82 connected to the underside of the corners 84 by hinges 86. Latch mechanisms 88 are provided to retain the support members in their retracted positions, shown in Figure 8A. When the latch member 88 is released, a spring 90 biases the support member downward, which in turn raises the frame from the floor 92.

It will be appreciated that other arrangements to increase the height of the device are within the scope of the invention.

In variations to the illustrated embodiments, the device is manufactured from a single mould, or multiple moulds, and the device therefore comprises of a single piece or two pieces of material which are reversibly or irreversibly mated together to form the complete frame shape. Mating may be achieved by a Mock and key' or tongue and groove joint. Such a device may contain a recess in the sides of the device, or more preferably in one or all of the corners of the device.

Various accessories to the device may be reversibly or irreversibly attached to the device by means of reversibly or irreversibly attaching the accessory to the recess or recesses. For example, an accessory may be provided which reversibly secures the device to the surface that the device is placed on, such as gym floor or swimming pool floor. Such accessories may include suction-cup type devices, hooks and other similar devices. In addition, an accessory may comprise a structure that is reversibly attached to the device via said recess or recesses, and which allows the device to be reversibly raised from the floor level to one of a plurality of predetermined height settings.

There are a number of ways to raise the height of the device using such accessories, including but not limited to use of a hinge, which may be spring-loaded or resilient, or a piston which pushes a part of the device corners and thus edges vertically upwards, thus raising the height of the device. The accessory for raising the height of the device will preferably be designed to 'collapse' or flex when exposed to a certain force, for example if stepped on by a user.

In a further variation, the underside of the frame is equipped with a non-slip surface with or a mechanism which will reversibly attach to the floor of the fitness studio or home, or swimming pool surface. The mechanism may include a suction surface or similar in order to prevent the device frame from tipping up or being moved along the surface on impact by the fitness student. Such a mechanism will prevent unintentional movement of the Device and importantly will allow the device to be easily detached from the surface. This may be as a result of a specific action of detaching components of the device, or may be aided by a dedicated mechanism for release of the attachment mechanism (such as a suction component).

The present invention provides a fitness device with many of the features of available step fitness devices but with a lower risk of injury. The invention also provides a fitness device and associated exercise routines which are accessible to fitness students of low and high fitness levels. Combinations of features described herein other than those expressly claimed fall within the scope of the invention.

Claims

1. A portable fitness device comprising: a frame, and an opening defined by the frame, wherein the device is configured to be placed on a surface such that the opening defines a step area and the frame separates the step area from a first region of the surface, and wherein the opening is configured to enable a user to step through the opening between the step area and the first region of the surface.

2. The portable fitness device as claimed in claim I, wherein the step area is at a height less than the height to which the frame extends above the surface.

3. The portable fitness device as claimed in claim 1 or claim 2, wherein the step area is a second region of the surface.

4. The portable fitness device as claimed in any preceding claim, wherein the dimensions of the device are adjustable.

5. The portable fitness device as claimed in claim 4, wherein the length and/or width of the device is adjustable.

6. The portable fitness device as claimed in claim 4 or claim 5, wherein the device is height adjustable.

7. The portable fitness device as claimed in any of claims 4 to 6, wherein the frame comprises slidable parts which enable the dimensions to be adjusted.

8. The portable fitness device as claimed in any of claims 4 to 7. wherein the frame comprises compressible parts which enable the dimensions to be adjusted.

9. The portable fitness device as claimed in any of claims 4 to 8, wherein the frame comprises flexible parts which enable the dimensions to be adjusted.

10. The portable fitness device as claimed in any of claims 6 to 9, wherein the height of the device is operable to be adjusted by flexing a component of the frame.

1 1. The portable fitness device as claimed in claim 10. wherein the frame comprises corners and side parts joining the corners, and the device is operable to be increased in height by bringing the corners closer together and causing the side parts to flex.

12. The portable fitness device as claimed in any of claims 6 to I I, wherein the device comprises a height adjusting member coupled to the frame, and the height adjusting member is moveable from a first position in which the frame extends to a first height above the surface, and a second position in which the frame extends to a second height above the surface, the second height being greater than the first height.

13. The portable fitness device as claimed in claim 12, wherein the height adjusting member comprises a support member configured to support a component of the frame in the second position.

14. The portable fitness device as claimed in claim 12 or claim 13, wherein the height adjusting member is biased towards the second position.

15. The portable fitness device as claimed in any preceding claim, further comprising a locking mechanism.

16. The portable fitness device as claimed in claim 15 when dependent on any of claim 12 to 14. further comprising a locking mechanism for retaining the height adjusting member in its first and/or second positions.

17. The portable fitness device as claimed in claim X. wherein the device is configured to flex or collapse when stepped on by a user.

18. The portable fitness device as claimed in any preceding claim, wherein the frame comprises a plurality of side parts, each side part comprising a base layer and a flexible upper layer disposed over the base layer, and the height of the frame is adjustable by flexing the upper layer on the base layer.

19. The portable fitness device as claimed in claim 18, wherein the height of the frame is adjustable by bringing opposing ends of the upper layer closer together.

20. The portable fitness device as claimed in claim 18, wherein the opposing ends of the upper layer are fixed relative to respective ends of the base layer, and the height of the frame is adjustable by changing the relative lengths of the upper layer and the base layer.

21. The portable fitness device as claimed in claim 20, wherein the height of the frame is adjustable by reducing the length of the base layer relative to the length of the upper layer.

22. The portable fitness device as claimed in any preceding claim, wherein the device is in the shape of a rectangle or square.

23. The portable fitness device as claimed in claim 22, wherein the device is rectangular with outer dimensions in the range of 75cm to 150cm along a first axis and 30 to 60cm along a second axis.

24. The portable fitness device as claimed in any preceding claim, wherein the frame comprises a non-slip surface.

25. The portable fitness device as claimed in claim 24, wherein the frame comprises an upper surface of non-slip soft rubber.

26. The portable fitness device as claimed in any preceding claim, wherein the device is configured to be used underwater.

27. The portable fitness device as claimed in any preceding claim, wherein the frame is provided with an attachment mechanism or material for attaching the device to the surface.

28. The portable fitness device as claimed in any preceding claim, wherein the step area is a surface of an elevated platform, formed to a height greater than the surface, and less than the height to which the frame extends above the surface.

29. The portable fitness device as claimed in claim 28, wherein the elevated platform is formed from an insert to the frame.

30. The portable fitness device as claimed in claim 29, wherein the insert is removable from the frame.

31. The portable fitness device as claimed in claim 28, wherein the elevated platform is integral with the frame.

32. The portable fitness device as claimed in any of claims 28 to 31. wherein the elevated platform has a plurality of sections with different heights.

33. The portable fitness device as claimed in any of claims 28 to 32, wherein the elevated platform has a plurality of height settings.

34. The portable fitness device as claimed any preceding claim, wherein the device is configured to be coupled to a second portable fitness device.

35. The portable fitness device as claimed in claim 34. wherein the second portable fitness device is a device according to any preceding claim.

36. The portable fitness device as claimed in claim 35, wherein the portable fitness device is configured to be stacked with an identical portable fitness device to create a device of increased frame height.

37. A portable fitness device comprising a frame defining an opening, wherein the device is configured to be placed on a surface such that the opening defines a first region of the surface and the frame separates the first region from a second region of the surface, and the opening is configured to enable a user to step through the opening between the first and second regions of the surface.

38. A method of exercising, the method comprising the steps of: a. providing a fitness device on a surface, the fitness device comprising a frame, and an opening defined by the frame; b. stepping through the opening between a step area defined by the opening, and a first region of the surface separated from the step area by the frame.

39. The method as claimed in claim 38. wherein the step area is a second region of the surface.

40. An aerobic fitness routine comprising instructions for carrying out the method as claimed in claim 38.

41. An aquatic aerobic fitness routine comprising instructions for carrying out the method as claimed in claim 38.

42. A data storage medium comprising instructions for carrying out the method as claimed in claim 38.

43. The data storage medium as claimed in claim 42 comprising audio-visual data.