WO2002038225A1

WO2002038225A1 - Exercise apparatus

Info

Publication number: WO2002038225A1
Application number: PCT/AU2001/001473
Authority: WO
Inventors: Wayne Ian Haynes
Original assignee: Honeywind Pty Ltd
Priority date: 2000-11-13
Filing date: 2001-11-13
Publication date: 2002-05-16
Also published as: CA2428645A1; DE10196905T1; US20040014571A1; AU2002214818A1; GB2387124A; GB0311401D0

Abstract

An exercise apparatus comprises an oblong platform (10;210) and at least one detachable convex instability member (30;70;90;230) projecting from the lower surface (12) of the platform (10). The platform is of sufficient length for a person to perform whole body exercises, eg in a prone, supine or semi-supine position, on the platform. The person exercising on the platform (10) faces the challenge of attempting to maintain the platform (10) in a horizontal orientation as it rocks or wobbles during the exercise, thus improving the balancing skills of the user. The apparatus may be provided in kit form with a plurality of interchangeable detachable convex instability members (30;70;90;230) of different forms, shapes and sizes to provide different balancing challenges of varying degrees of difficulty. The apparatus or kit may also include one or more exercise aids or attachments, eg bars (52) and exercise balls (250) mountable on the upper surface (11;211) of the platform (10;210).

Description

EXERCISE APPARATUS Field of the invention

The invention relates to exercise apparatus and relates particularly, though not exclusively, to exercise apparatus which is suitable for rehabilitation of muscles, tendons, joints and neural control of the human body.

Background of the invention

The research literature relating to exercise physiology is generally in favour of exercises which are performed in unstable environments, as such exercises can have many and varied potential benefits, including:

(a) improving the speed of muscle contraction to stabilise the body from falling or loosing balance.

(b) improving the strength of muscle contraction, due to the use of eccentric and concentric muscular contractions

(c) improving general balance and co-ordination.

To date, one exercise device which uses this principle of an unstable environment is the so-called "Swiss ball", which is a large resilient inflatable ball which can be used in a variety of exercises. It is found to be an excellent tool for general exercise as well as the rehabilitation of musculo-skeletal injuries. However, there are various exercises that cannot adequately be performed with the use of a Swiss ball of the type described.

It is desirable to provide an exercise apparatus which allows a wide range of beneficial exercises to be performed by a user. Summary of the invention

The present invention resides in a recognition that there can be advantageously provided an exercise apparatus which has a rigid but unstable surface on which whole body exercises can be performed.

According to one aspect of the invention there is provided an exercise apparatus comprising a platform having an upper surface and a lower surface, and an instability means including at least one convex member projecting from the lower surface of the platform.

Preferably, the at least one convex member is detachable so that it can be replaced with one or more other convex members having differing profiles which consequently provide different stability characteristics. This preferably allows a user to vary the characteristics of the device to allow different exercises to be performed with the apparatus.

Preferably, the platform is large enough for a user to perform whole body exercises in a number of different positions, including prone, supine, sitting, standing and on hands and knees. According to another aspect of the invention, there is provided an exercise apparatus comprising a platform having an upper surface and a lower surface, and an instability means comprising at least one convex member projecting from the lower surface of the platform, wherein the platform is of sufficient dimensions to allow whole body exercises to be performed on the platform with substantially full body contact, eg in a prone, supine or semi-supine position, without the body having to contact another support or support surface.

The platform is preferably oblong in shape and, as an example, the dimensions of the platform preferably fall substantially within the range from about 1.5m to about 3.0m in length and about 0.6m to about 2.1m in width. Preferably, the upper surface of the platform is covered in a resilient rubber-like material.

Preferably, the lower surface of the platform includes a plurality of fixtures to which the at least one convex member can be detachably secured.

Preferably, the at least one convex member attached to the platform is such that the platform occupies a substantially horizontal position of equilibrium when standing at rest on a substantially flat horizontal surface. In use, when the platform carries the body weight of a person, the apparatus is preferably designed such that when the centre of gravity of the person is offset in a horizontal direction from the centre of gravity of the apparatus, the platform becomes unstable and rocks or wobbles from its position of equilibrium. The person then faces the challenge of attempting to keep the platform substantially horizontal while performing any number of simple or complex exercises on the apparatus.

The at least one convex member preferably has a part-cylindrical, part- spherical or part-ovoid curved surface which is designed to stand on the ground or other generally horizontal surface.

In one embodiment, at least two convex members, such as part- cylindrical rocker members, are attached to the lower surface of the platform at spaced intervals from the centre of the platform.

In another embodiment, a single convex member, preferably in the form of a dome-shaped member, is attached to the lower surface of the platform. The centre of the dome-shaped member is preferably disposed with its centre directly below the centre of the platform. The platform of the apparatus may have mounting means on its upper surface for mounting exercise attachments, such as bars, on the platform.

According to a further aspect of the invention, there is provided an exercise apparatus comprising a platform having an upper surface and a lower surface, an instability means comprising at least one convex member projecting from the lower surface of the platform and at least one exercise attachment mounted on the upper surface of the platform.

In one embodiment, the at least one exercise attachment comprises a transversely extending bar supported above the platform by at least one upwardly extending member. It will, however, be appreciated that different kinds of exercise aids and attachments may be mounted on the upper surface of the platform for different exercises. In another embodiment, the exercise attachment comprises an exercise ball mounted on the platform. For this purpose, the platform may have a removable circular portion which, when removed, leaves a circular opening in the platform for receiving the exercise ball.

The apparatus may also include handle means for carrying the platform.

The handle means may conveniently be constituted by shaped apertures forming hand holds in the platform.

According to another aspect of the invention, there is provided an exercise kit comprising a platform having an upper surface and a lower surface, and a plurality of instability means comprising detachable convex members removably attachable to the lower surface of the platform, said detachable convex members having different profiles providing different stability characteristics when attached to the platform. Brief description of the drawings

Various preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a top perspective view of a platform of exercise apparatus in accordance with the invention;

Figure 2 is a bottom perspective view of the platform of Figure 1 ;

Figure 3 is a side view of an embodiment of exercise apparatus with two rocker members attached to the platform;

Figure 4 is an end view of the exercise apparatus of Figure 3;

Figure 5 is a side view of the platform of Figure 1 with bar members attached to the upper surface;

Figure 6 is an end view of the platform of Figure 5;

Figure 7 is a side view of another embodiment of exercise apparatus with a dome-shaped member attached to the platform;

Figure 8 is an end view of the apparatus of Figure 7;

Figure 9 is a side view of a further embodiment of exercise apparatus with a different dome-shaped member attached to the platform;

Figure 10 is an end view of the apparatus of Figure 9;

Figure 11 is a plan view of a modular platform; Figure 12 is a side view of the platform of Figure 11 ;

Figure 13 is a plan view of another modified embodiment of exercise apparatus;

Figure 14 is a section on the line 14 - 14 of figure 13;

Figure 15 is a plan view of one end of the apparatus of Figure 13 with an exercise ball mounted on the platform;

Figure 16 is an end view of the apparatus including the exercise ball; and

Figure 17 is a section on the line 17 - 17 of Figure 15.

Description of preferred embodiments

Figures 1 and 2 show a platform 10 for exercise apparatus having an upper surface 11 and a lower surface 12. A plurality of attachment members 13, and 14 are provided on the lower surface 12 of the platform 10 to which one or more detachable convex rocker members 30, 70 or 90 are designed to be attached to form different embodiments of exercise apparatus in accordance with the invention.

The platform 10 preferably comprises a generally oblong shaped board having substantially straight sides 15 and curved ends 16. The platform 10 may be made of any substantially rigid material which is designed to carry the weight of a person on the platform. Suitable materials for construction of the platform include wood, such as a sturdy craftwood, metal and substantially rigid plastics materials. Preferably, the upper surface 11 of the platform 10 is covered with a layer of cushioning material 17 (Fig. 3), such as a rubberised matting material of the type which is used for exercise mats.

The platform 10 is designed to support the weight of a person in a number of different positions, including prone and supine positions. The length of the platform preferably falls substantially within the range from about 1.5m to about 3m. The width of the platform preferably falls substantially within the range from about 0.9m to about 2.1m.

Referring more specifically to Figure 2, the attachment members 13, 14 are in the form of elongate fixtures secured to the lower surface 12 of the platform 10, eg by screws or other fixing means. Each fixture 13, 14 has side limbs 22 which are shaped to define a channel 24 between the limbs 22. As shown in Figure 2, two pairs of parallel attachment members 13 and 14 extending laterally across the platform 10 are provided. A first pair of the attachment members 13 are provided towards the curved ends 16 of the platform 10 and the second pair of attachment members 14 are provided in a more central position on either side of the centre of the platform 10. It will, however, be appreciated that the number, form and location of the attachment members may vary for different types of exercise apparatus in accordance with the invention.

As shown in Figure 1, the platform 10 has a plurality of mounting recesses 18 in its upper surface 11 for mounting exercise attachments 50 to the platform 10 as will be described in greater detail with reference to Figures 5 and 6. The platform 10 also has a pair of curved apertures 19 located adjacent the sides 15 of the platform 10 at intermediate positions along the length of the platform 10 to provide hand holds for carrying the platform when not in use.

Figures 3 and 4 show an embodiment of exercise apparatus in accordance with the invention in which a pair of convex instability members in the form of rocker members 30 are detachably mounted to the first pair of attachment members 13 towards the ends 16 of the platform 10. Each rocker member 30 is substantially D-shaped having a part-cylindrical lower surface 32, two opposed, substantially flat end surfaces 34 and a substantially flat upper surface 36. An elongate attachment portion 38 provided on the upper surface 36 of the rocker member 30 is adapted to slide into the channel 24 of a respective attachment member 13 on the lower surface 12 of the platform 10 and the rocker member 30 may be secured in position by a releasable locking means (not shown).

In use, when resting on a substantially horizontal surface, the exercise apparatus of Figures 3 and 4 provides a flat platform which normally occupies a substantially horizontal position of equilibrium, but which becomes unstable and rocks when a person is positioned on the platform 10 with his/her centre of gravity offset from the central longitudinal axis of the platform 10. The principal use of the exercise apparatus is for the person to perform exercises, simple or complex, on the platform 10 whilst at the same time adjusting and correcting his/her position on the platform 10 in an attempt to balance on the platform 10 by attempting to restore or maintain the platform 10 in a substantially horizontal orientation.

The exercise apparatus of Figures 3 and 4 is preferably provided as a kit including a number of differently shaped detachable rocker members 30 so that the degree of difficulty in balancing on the platform 10 may be varied by substituting one pair of rocker members for another. For instance, flatter shaped rocker members 30 having a larger radius of curvature of the curved surface 32 may provide an easier balancing challenge than rounder or deeper angled rocker members 30 having a smaller radius of curvature. The dimensions of the rocker elements 30 may vary from about 5cm to 30cm in length and from about 4cm to 30cm in depth and they can be from about 2cm to 5cm thick.

Figures 5 and 6 show a pair of upper exercise attachments 50 attached to the upper surface 12 of the platform 10. Each exercise attachment 50 comprises a laterally extending cylindrical bar 52 supported above the platform 10 by posts 54 at each end of the bar 52. The upper ends of the upright members 52 are joined to the bar 52 and the lower ends of the posts 54 are releasably mounted in the mounting recesses 18 in the upper surface 12 of the platform 10. The exercise attachments 50 are provided to broaden the range of exercises which may be performed on the platform. For instance, if only one of bars 52 is used, a person may hook his or her feet around the bar 52 at one end of the platform 10 and perform sit ups on the platform. Alternatively, a bar 52 may be gripped by a person's hand while performing body curls on the platform.

Whilst there are no rocker members shown in Figures 5 and 6, rocker members 30 such as in Figures 3 and 4, or a member 70, 90 of the type which will be described with reference to Figures 7 to 10, will normally be attached to one or more of the attachment members 13, 14 on the lower surface 12 of the platform 10 so that the person exercising on the platform has to balance in addition to performing exercises, such as sit ups.

It will also be appreciated that the types of exercise attachments which may be detachably mounted to the upper surface of the platform 10 are not limited to bars 52 and that other types of exercise attachments may be provided for different exercises.

Figures 7 and 8 show another embodiment of exercise apparatus in accordance with the invention in which a single dome-shaped instability member 70 is detachably mounted to the second pair of attachment members 14 in a central position on the lower surface 12 of the platform 10. The dome- shaped rocker member 70 is preferably formed from a part-spherical metal dome having a part-spherical lower surface 72, a board 73 provided on a substantially flat upper surface 74 of the dome and a pair of attachment portions 76 on the board 73 on the upper surface 74. Each attachment portion 76 is adapted to slide into the channel of a respective one of the second pair of attachment members 14 and to be secured in position by a releasable locking means (not shown).

As in the embodiment of Figures 3 and 4, the exercise apparatus of Figures 7 and 8 provides a flat platform 10 which normally occupies a substantially horizontal position of equilibrium when resting on a substantially horizontal surface. However, when a person is supported on the platform with his/her centre of gravity offset in a lateral direction from the centre of the platform 10 and dome-shaped member 70, the platform 10 will tilt from its horizontal level position. The dome-shaped member 70 therefore allows for tilting or wobbling movements of the platform 10 in all directions thus presenting a person exercising with a more difficult challenge to balance on the platform 10 by maintaining the platform 10 in a substantially horizontal position while performing exercises on the platform 10.

The degree of difficulty in balancing on the platform 10 may be varied by providing a number of detachable dome-shaped members 70 of varying shape, size and radius of curvature. For instance, the diameter of the dome-shaped member 70 may vary from about 15 cm to about 40cm or more, and the depth of the dome-shaped member 70 may vary from about 10cm to about 40cm or more.

Referring to Figures 9 and 10, there is shown a modified embodiment of an exercise apparatus having a dome-shaped member 90 of a different shape releasably attached to the lower surface 12 of the platform 10. The dome- shaped member 90 is preferably formed from a part-ovoid shaped dome having a part-ovoid lower surface 92, a board 93 covering a substantially flat upper surface 94 of the dome and a plurality of attachment portions 96 on the board 93. Each attachment portion 96 is adapted to slide into the channel of a respective one of the attachment members 13, 14 on the lower surface 12 of the platform 10 and to be secured in position by a releasable locking means (not shown).

The exercise apparatus of Figures 9 and 10 may be used in similar manner to the apparatus of Figures 7 and 8. However, because of the part-ovoid surface 92 of the dome-shaped member 90, the main tilting or wobbling movement of the platform 10 from its substantially horizontal position will be a rocking movement from side to side with a lesser degree of tilting from end to end.

Figures 11 and 12 show a modular construction of a platform 100 for exercise apparatus in accordance with the invention. The platform 100 is formed from three parts, a central part 110 and a pair of end parts 120, 130. The central part 110 has a pair of straight side walls 111 and a pair of end walls 112. Each end wall 112 has a central protruding portion 114. The end parts 120, 130 each have straight side walls 12, a curved end wall 122 and an opposite end- wall 123 with a recess 124 of complementary shape to the protruding portion 114 of the adjacent end wall 112 of the central part 110. The cross-sectional shapes of the adjacent end walls 112, 122 of the central part 110 and the end parts 120, 130 are such that the end walls 112, 122 engage with each other to form a mortice and tenon joint and the parts 110, 120, 130 are locked together by releasable locking clips 115 on the side walls 111 of the central part 110 which engage over projections 125 on the side walls 121 of the end parts 120, 130.

As shown in Figures 11 and 12, the central part 110 is provided with a pair of attachment members 14 on its lower surface 12 and a pair of apertures 19 forming hand holds are provided adjacent the sides of the central part 110. Each end part 120, 130 is provided with an attachment member 13 on its lower surface 12 and a pair of mounting recesses 18 on its upper surface 11. Thus, when the platform 100 of Figures 11 and 12 is fully assembled it has essentially the same features as the platform 10 of Figures 1 and 2 and may be used to form exercise apparatus as in any one of the embodiments of Figures 3 to 10 by releasably attaching different convex instability members to the attachment members 13 and/or 14.

A modular platform is also advantageous in that the central part 110 may be used with only one of the end parts 120 or 130 to provide an exercise platform of shorter length when the full length of the three part platform 110 of Figures 11 and 12, for example, for some exercises such as sit-ups with one exercise bar attachment 50 mounted in the recesses 18 of the end part 120 or 130. With such a shorter platform, a pair of rocker members 30 of the kind shown in Figures 3 and 4 may be attached to the attachment member 13 and the end attachment member 14 on platform part 110, or a dome-shaped instability member 70 or 90 of the kind described with reference to Figures 7 to 10 may be attached to the central attachment member 14 or to all three of the attachment members 13, 14 of the two-part platform.

Another modified embodiment of an exercise apparatus 200 in accordance with the invention is shown in Figures 13 to 17. The apparatus is similar to that of Figures 3 and 4 in that it comprises an oblong platform 210 with a plurality of convex instability members in the form of D-shaped rocker members 230 detachably mounted to a pair of transverse attachment members 213 on the lower surface 212 of the platform towards the ends 216 of the platform 210. If required, a central rocker member 232 may also be detachably mounted to a central transversely extending attachment member 214. Alternatively, a dome-shaped instability member, such as one of the dome- shaped members 70, 90 described with reference to Figures 7 to 9, may be mounted to one or more of the attachment members 213, 214. The exercise apparatus of Figures 13 to 17 differs primarily from those of the previous embodiments in that the platform 210 has a removal circular portion 220 which, when removed, creates a circular opening 222 forming a mounting means for mounting on the upper surface 211 of the platform 210 an exercise aid or attachment in the form of a large exercise ball 250 of the type known as a "Swiss ball".

The exercise ball 250 is received in the circular mounting opening 222 such that only a small part of the ball 250 extends below the lower surface 212 of the platform 210 with most of the ball 250 extending above the upper surface 211 as shown in Figures 15 to 17. The exercise ball 250 may be secured in position by a plurality of straps 240. Each strap 240 has one end attached to a securing means, such as a hook, for attachment to a mount 242 provided in the upper surface 211 of the platform 210 and the straps 240 extend over part of the circumference of the ball 250 and are joined together, eg by being sewn or otherwise secured to a piece of material 245 disposed on top of the ball 250. As shown in Figure 15, three straps 240 are provided, though the number and form of straps may be varied, if required.

The straps 240 are preferably formed from an elastic material to assist in mounting and securing the exercise ball 250.

In use, the exercise ball 250 mounted on the platform provides the user with a wider variety of possible exercises. For example, the user may lean on the exercise ball 250 with the upper part of his/her body supported by the ball and his feet on the other end of the platform 210.

The user can then perform whole body exercises on the exercise ball 250 and, at the same time, attempt to maintain the platform in a substantially horizontal orientation, thereby improving his/her balance skills. In this case, the exercise ball 250 act as a fixed apparatus on an unstable supporting platform 220, in contrast to the normal use of a Swiss ball, which is a moveable apparatus on a fixed surface, eg the ground.

From the foregoing, it will be appreciated that the present invention provides a versatile exercise apparatus having a platform for exercising to which different forms and shapes of instability members and exercise attachments may be detachably mounted so that the person using the apparatus may perform a wide variety of exercises in a number of different positions on the oblong platform, including the following positions: prone, supine, semi-supine, quadruped (four point hand and knee contact), standing, lunge and squatting.

The exercise apparatus provides different levels of difficulty challenges ranging from gentle rocking movement with rocker attachments having a gentle curved surface, to exercises with a centrally positioned dome-shaped member that provides freedom of movement for the platform to tilt not only from side to side but also back and forth and in all combinations of these two directions.

The apparatus of the invention also allows for different levels of capability and when a novice has improved his balance skills with a gently curved instability member, the challenge can be increased by changing the detachable instability member with another instability member having a more sharply curved surface.

The exercises may be performed on the platform either with or without weights, exercise attachments on the upper surface of the platform or other external exercise devices, such as ab-rockers.

The exercise apparatus of the present invention enables unique balancing exercises to be performed and can be used in a wide variety of locations, such as rehabilitation centres, gymnasiums and in the home. It is also readily transportable and can be easily carried by means of the handholds 19.

It will be appreciated that various modifications and additions may be made to the preferred embodiments described above with reference to the drawings without departing from the scope and spirit of the present invention. For example, in another alternative embodiment, a number of resilient members, such as coil springs, may be mounted on the lower surface of the platform in addition to the at least one convex member, so that the apparatus is put under tension when it rocks, tilts or wobbles.

Claims

1. An exercise apparatus comprising a platform having an upper surface and a lower surface, and an instability means including at least one convex member projecting from the lower surface of the platform.

2. An exercise apparatus according to claim 1 wherein the platform is of sufficient dimensions to allow a person to perform whole body exercises on the platform with substantially full body contact.

3. An exercise apparatus according to claim 2 wherein the platform is oblong in shape having a length falling substantially within the range from about 1.5m to about 3.0m.

4. An exercise apparatus according to claim 3 wherein the width of the platform falls substantially within the range from about 0.6m to about 2.1m.

5. An exercise apparatus according to any one of the preceding claims wherein said at least one convex member is such that the platform occupies a substantially horizontal position of equilibrium when standing at rest on a substantially flat surface.

6. An exercise apparatus according to claim 5 wherein the apparatus is designed such that, when the platform carries the body weight of a person and the centre of gravity of the person is offset in a horizontal direction from the centre of gravity of the apparatus, the platform becomes unstable and rocks or wobbles from its horizontal position of equilibrium.

7. An exercise apparatus according to any one of the preceding claims wherein said at least one convex member has a curved lower surface which is arranged to stand on the ground or other generally horizontal surface.

8. An exercise apparatus according to claim 7 wherein the curved surface of said at least one convex member is part-cylindrical.

9. An exercise apparatus according to claim 7 wherein the curved surface of said at least one convex member is part-spherical or part-ovoid.

10. An exercise apparatus according to any one of claims 1 to 7 wherein the instability means comprises a plurality of convex members provided on the lower surface of the platform.

11. An exercise apparatus according to claim 10 wherein said plurality of convex members are part-cylindrical rocker members.

12. An exercise apparatus according to any one of claims 1 to 7 wherein the instability means comprises a single convex member provided on the lower surface of the platform.

13. An exercise apparatus according to claim 12 wherein the single convex member is dome-shaped.

14. An exercise apparatus according to claim 13 wherein the dome-shaped convex member has a part-spherical lower surface.

15. An exercise apparatus according to claim 13 wherein the dome-shaped convex member has a part-ovoid lower surface.

16. An exercise apparatus according to any one of claims 13 to 15 wherein the dome-shaped member is disposed with its centre directly below the centre of the platform.

17. An exercise apparatus according to any one of the preceding claims wherein said at least one convex member is detachably mounted on the lower surface of the platform.

18. An exercise apparatus according to claim 17 wherein the lower surface of the platform includes a plurality of fixtures to which said at least one convex member can be detachably secured.

19. An exercise apparatus according to claim 18 wherein said plurality of fixtures include parallel attachment members extending laterally across the lower surface of the platform.

20. An exercise apparatus according to claim 19 wherein the attachment members each define a channel for receiving an attachment portion on the upper surface of said at least one convex member.

21. An exercise apparatus according to any one of the preceding claims wherein the platform has mounting means for mounting at least one exercise attachment on its upper surface.

22. An exercise apparatus according to claim 21 wherein an exercise attachment comprising a transversely extending bar is mounted on the upper surface of the platform.

23. An exercise apparatus according to claim 22 wherein the transversely extending bar is supported above the platform by posts received in recesses in the upper surface of the platform.

24. An exercise apparatus according to claim 21 wherein an exercise attachment comprising an exercise ball is mounted on the upper surface of the platform.

25. An exercise apparatus according to claim 24 wherein the platform has a removable circular portion which, when removed, leaves a circular opening in the platform for receiving the exercise ball.

26. An exercise apparatus according to claim 24 or claim 25 wherein the exercise ball is secured to the upper surface of the platform by one or more straps extending over the exercise ball and having ends attached to the platform.

27. An exercise apparatus according to any one of the preceding claims wherein the upper surface of the platform is covered with a resilient, rubber-like material.

28. An exercise apparatus according to any one of the preceding claims wherein the platform is of modular construction and is formed from a plurality of platform parts.

29. An exercise apparatus according to claim 28 wherein the platform has a central part and a pair of end parts.

30. An exercise apparatus according to claim 28 or claim 29 wherein each of the platform parts has at least one attachment member for a detachable convex member on its lower surface.

31. An exercise apparatus according to any one of claims 28 to 30 wherein adjacent ends of the platform parts have interengageable formations.

32. An exercise apparatus according to any one of claims 28 to 31 wherein releasable locking clips are provided for securing the platform parts together.

33. An exercise apparatus according to any one of the preceding claims wherein the apparatus includes handle means for carrying the platform.

34. An exercise apparatus according to claim 33 wherein the handle means is constituted by shaped apertures in the platform forming hand holds.

35. An exercise apparatus according to any one of the preceding claims wherein a plurality of detachable convex members having different profiles are provided so that said at least one convex member on the lower surface of the platform can be replaced with one or more other convex members to provide different stability characteristics for the apparatus.

36. An exercise kit comprising a platform having an upper surface and a lower surface, and a plurality of instability means comprising detachable convex members removably attachable to the lower surface of the platform, said detachable convex members having different profiles providing different stability characteristics when attached to the platform.

37. An exercise kit according to claim 36 wherein the plurality of detachable convex members include part-cylindrical rocker members.

38. An exercise kit according to claim 37 wherein the part-cylindrical rocker members include a first set of substantially D-shaped rocker members having a curved surface with a relatively large radius of curvature, and a second set of substantially D-shaped rocker members having a curved surface with a smaller radius of curvature.

39. An exercise kit according to any one of claims 36 to 38 wherein the plurality of detachable convex members include at least one dome-shaped member.

40. An exercise kit according to claim 39 wherein a number of detachable dome-shaped members of varying size and/or shape and/or radius of curvature are provided.

41. An exercise kit according to any one of claims 36 to 40 wherein the kit includes at least one exercise attachment for mounting on the upper surface of the platform.

42. An exercise kit according to claim 41 wherein an exercise attachment comprising at least one raised bar is provided for mounting on the upper surface of the platform.

43. An exercise kit according to claim 41 or claim 42 wherein an exercise attachment comprising an exercise ball is provided for mounting on the upper surface of the platform.

44. An exercise kit according to claim 43 wherein the platform has a removable circular portion which, when removed, leaves a circular opening in the platform for receiving the exercise ball.

45. An exercise kit according to claim 43 or claim 44 wherein the kit includes at least one strap attachable to the platform for securing the exercise ball in position.

46. An exercise kit according to any one of claims 36 to 45 wherein the platform is of modular construction and is formed from a plurality of detachable platform parts.