The present invention relates to a sitting posture-regulating rest device for use with a chair, optionally a chair placed at a table, and where the chair seat optionally is backwardly tiltable in relation to the chair support, and as defined in the preamble of the attached patent claims.

Very many people, caught up in a hectic lifestyle with an emphasis on cerebral activity, feel the need to rest the muscles of the body at the end of the day, thereby reducing everyday stress, and this despite a low level of physical activity during the day.

Even though many people use little bodily energy and sit for long periods of time in front of the television, in the car, at the office or other places, the need for rest and tranquility still exists. In addition, our posture when we sit is often incorrect and results in our abdominal muscles becoming slack, and our circulation in compressed abdominal organs poor.

In spite of the fact that it is generally known that physical activity is healthy for the body, both physically and psychologically, many prefer to rest because they feel in poor shape mentally. Furthermore, it has been established that our modern lifestyle is often responsible for a number of health problems. A low level of muscular activity in the body combined with posturally poor sitting habits, gives rise to a poorer result in terms of health for very many people, and one contracts the so-called scourges of modern society. These manifest themselves most often in the form of various

circulatory disorders and illnesses caused by strain which affect many who are prone to such low levels of muscular activity.

It is therefore vital to adapt a lifestyle for both patients suffering from illnesses caused by strain and healthy people so that they can independently maintain good health. Gymnastic and strengthening exercises may be a part of the treatment to stabilise the treatment result which is attained. They may also form a part of a person's everyday lifestyle as general prophylaxis. However, it often the case that after a short time the majority of people will "forget" the exercises, because their lifestyle calls for more of their attention in other areas, and often also because at the time they feel well. Many people often experience standing in front of the mirror in the morning and observing that so- called "spare tyres" have developed around their stomach. The intention to start exercising may be the best per se, but when evening comes and one is mentally drained, the decision "to begin tomorrow" is taken. For many people, "spare tyres" of this kind are an additional extra to the daily psychological stress.

Weakened abdominal, pelvic, femoral and back muscles caused by stooping and passive sitting postures are, according to medical and chiropractic specialist literature, a common cause of many back complaints and circulatory disorders. This a well-known syndrome for most people.

To be able to sit in a correct posture naturally increases the use of the muscles in the abdominal region, but does not in itself give any particular exercise effect because at any given time one attempts to sit in a balanced position which gives a relatively low level of energy consumption. All the chairs which are on the market today, including specialist chairs and others with a ventral leg rest, endeavour to give a correct sitting posture which is as relaxing as possible so

that the user will be able to sit for as long as possible without his musculature becoming exhausted owing to the posture he maintains whilst sitting.

Even if one sits in a posturally correct and agreeably balanced manner, and in spite of the help one is given to adopt such a position with the use of a ventral leg rest, the strengthening exercise effect on the muscles gained in a posturally balanced sitting position will be poor unless one leans back and puts oneself out of equilibrium or off balance. Even if the chair is not designed to have a ventral leg rest, there is always the possibility of hooking one's legs under something and leaning backwards, thereby securing some exercise effect. However, the problem is that the majority of people do not manage to sit in this way and at the same time concentrate on other work without the body gradually and automatically adopting the most relaxing sitting posture available. In fact, muscular activity has a disturbing effect on a person's powers of concentration. On the market today there are a number of specially constructed chairs with a ventral leg rest which one can use as an aid to exercise by leaning backwards and bringing oneself out of equilibrium. As a rule, these are not constructed for this function and the chair itself may be tilted out of equilibrium. A regular sit- ups bench or a special device for the purpose would therefore be better. One of the objectives of the present invention is therefore to provide a sitting posture-regulating rest device which can be used both to strengthen muscles and at the same time to give a posturally correct seated work position on a normal chair. A further objective of the invention is therefore also to make the chair user tense his abdominal muscles in order to be able to sit in a balanced and correct manner on the chair. With a such a solution, the aim is to control the muscles in the abdominal region and give a posturally better sitting position in that the body, when brought out of balance, will be able to regain balance by increased muscle use in such a way that through tensing

muscles one thus gets some exercise and can maintain a posturally correct sitting position for daily use. Such a manner of sitting will be somewhat different than other known manners, since in contrast to the usual manners of sitting which seek to create balance in the body and long exhaustion time for the muscles, this manner now seeks to reduce exhaustion time and increase energy consumption in the muscles, chiefly in the femoral, pelvic, back and abdominal muscles. To attain an effect of this kind, a ventral support against the legs is required, optionally a dorsal support under the sole of the foot/toes, to correct the imbalance created owing to the seating device. One of the objectives of the present invention is thus to provide a possiblility to correct such imbalance, whilst the chair user has the opportunity to perform some gymnastic exercises without overbalancing completely.

However, many ways of strengthening and activating abdominal, pelvic, femoral and back muscles are previously known. One of the most well-known is the gymnastic exercise known as sit- ups where the legs are hooked under a ventral support on the foreside of the toes, instep, ankle, calf or thigh. For instance, the feet could be locked under a set of wall bars or under a bed, or the toes may be put under a chest of drawers. In this way, the muscles can be strengthened in the that the upper body under the control of the said muscles is allowed to lean backwards in relation to the balancing, vertical position and is flexed up and down in that one lies down and then sits up again. The regular sit-up bench is, of course, not suitable as a seat for a normal sitting posture.

There are also known solutions wherein ventral leg rests support the knees, feet, ankles or thighs and provide assistance to people who are to stand up or sit down, or who wish to sit in a particular balanced position.

Seating/walking means with ventral rest devices which stabilise and help people with physical weaknesses and prevent them from overbalancing are also known. Such means are known, inter alia, from Norwegian Patent Application No. 845021.

Furthermore, there are also seating devices with ventral leg rests in soft, resilient materials to enable people to sit in different places, e.g., along a wall or very close to one another in a bus, and preferably sit in a safe, good and comfortable manner and in upright balance with the least possible tension in the body and muscles. Solutions of this kind are disclosed in, e.g., Norwegian Patent Application No. 821888.

The known seating devices and chairs all have in common the fact that they are supposed to achieve a best possible, posturally correct, balanced and relaxed sitting position. However, this is in reality the opposite effect to what is desirable if one seeks to achieve an automatic strengthening of femoral, pelvic, back and abdominal muscles in a sitting position.

If one is to achieve an automatic strengthening effect one must sit in imbalance and with muscular tension. One must therefore aim to have a certain degree of imbalance in a seating structure.

The features of the rest devices according to the present invention that are characteristic of the invention will be disclosed in the patent claims below.and also the following description with reference to the attached drawings.

It will be understood immediately that the exemplary embodiments illustrated in the drawings and described in the accompanying description are only to serve the purpose of allowing the inventive idea to be comprehended, since it will be obvious to a person versed in the art to carry out

modifications of the chair's appearance and the design, padding and so forth of the rests. When pads or rest pads are described below, this shall be understood to mean thigh, calf or foot rests of any type suitable for the purpose. As examples of the invention, that are not- limiting, ordinary cushioned pads, rests made with the aid of integral foam and so forth are conceivable.

Fig. 1 illustrates a first embodiment of the device according to the present invention.

Fig. 2 shows a modification of the device in Fig. 1.

Fig. 3 shows in more detail the adjusting function of the device in Fig. 2.

Fig. 4 shows a modification of the device in Figs. 1, 2 and 3.

Fig. 5 shows a modification of the design of the rest pad as shown in Figs. 2, 3 and 4, to illustrate in more detail the design of the rest pad in Fig. 1.

Figs. 6 and 7 illustrate a second embodiment of the device according to the present invention.

Figs. 8 and 9 illustrate a third embodiment of the device according to the present invention.

Figs. 10 and 11 illustrate a fourth embodiment of the device according to the present invention.

Fig. 12 illustrates a fifth embodiment of the device according to the present invention.

Fig. 1 depicts a chair user 1 sitting on a chair 2 at a work

table 3. The seat 4 of the chair 2 may optionally be backwardly tiltable in relation to the chair support. The chair 2 may optionally also be provided with a back 5. To provide the said rest device, there is mounted on the underside of the tabletop- 3 a ventral thigh rest which is adjustably attached to a mount 7 on the underside of the tabletop 3. To adjust the distance of the thigh rest 6 to the underside of the table a runner 8 is provided which changes the angle of inclination of mount portion 9 which supports the actual thigh rest 6.

Fig. 5 illustrates in more detail a preferred embodiment of the actual thigh rest 6 in Fig. 1, consisting of two pads 6' and 6'' that are spaced apart but mechanically connected to one another.

In the embodiment which is shown in Fig. 2 the rest pad has, however, a somewhat flatter design, and is designated by the reference numeral 10. Inclined arms 11 support the pad 10 and additional inclined arms 12 make possible the adjustment of the distance between the pad 10 and the underside of the tabletop. The principle of the mechanism in Fig. 2 is shown in more detail in Fig. 3, where it will be seen that the distance of the pad from the front edge of the table 3 can also be adjusted by means of a sliding block means 13 which will slide in relation to a sliding rail 14 attached to the tabletop.

Fig. 4 shows a modification of the solution in Fig. 3, where the arms 11, 12 in Fig. 3 are replaced by one or two bow- shaped members 15 capable of being displaced in relation to the sliding block 13 in order to thereby vary the distance of the rest pad 10 from the underside of the tabletop 3. In other respects, the mode of operation is as explained in connection with Fig. 3.

A person versed in the art will understand immediately that

further and technical solutions equivalent to those shown in Figs. 1 to 5 are conceivable without thereby deviating from the inventive idea.

Figs. 6 and-7 illustrate a further embodiment of the device according to the invention, where the chair, in accordance with the exemplary embodiment, has a seat 16 connected to a pair of runners 17, 18 which, via a downwardly projecting part, gradually become horizontal parts. In the vicinity of the transition between the downwardly projecting part and the horizontal part a leg rest 19 is provided so that the chair user 1 can put the back of his foot or ankle to rest against this sideways outwardly projecting leg rest. In this way the chair user obtains a support at the lower portion of the fibula, which ensures that the abdominal muscles receive sufficient assistance to be able to bring the upper part of the body back to the desired sitting posture after tilting backwards.

Yet a further embodiment is illustrated in Figs. 8 and 9, which must almost be perceived as a continuation of the inventive idea according to what is shown in Figs. 6 and 7. In this case the chair 20 consists of a support 21 which is virtually a flat part and where this flat part 21 at the front edge thereof has an upward-turned piece 22 which gradually becomes a narrow upwardly projecting part 23, and where said part furthermore at the top gradually becomes the actual seat 24. The said part 22 will serve as a foot rest, said part being of a width, height and gradient which are such that the part is capable of forming a contact surface against the chair user's toes 1' .

The chair 8 illustrated in Fig. 8 has cross-section which is roughly C-shaped or has the configuration of a letter U on its side. Said flat part 21, the erect part 22 thereof, the upwardly projecting part 23 and also the seat may preferably be made uniformly, e.g., of plastic, wood laminate or metal.

In the solution shown in Figs. 10 and 11, the chair has runners 25 and 26 which are constructed in an upward direction and support a seat 27, and at the front edge are constructed in an upward direction and bear rest pads 28 and 29 which are to form contact faces against the chair user's legs at a region 1 ' ' below the user's knees. Alternatively, the runners may terminate in thigh rests 30, 31 above the knee, such that they rest against the front of the thighs, see Fig. 12. The runners 25 and 26 are preferably in the forward upwardly projecting part slightly yielding in the forward direction of the chair. In the case of the present rest devices, it will be seen that the ventral leg rest will be capable of relieving a number of largish muscle groups from the pelvis and thighs down to the proximal part of the fibula, so that they do not take part in the muscular action to the same extent in order to maintain balance and equilibrium of the vertical posture of the upper part of the body. Thus, the exercise effect will be greater for the abdominal muscles because the load will be increased for this musculature. It is also important in connection with the embodiment in Figs. 1 to 5 that the ventral leg rest is positioned such that it dos not push the chair away.

An automatic exercise effect is achieved by means of the present invention since the aim is that the chair user must sit in imbalance and in a state of muscular tension. By having a ventral thigh or leg rest in connection with the chair, and having a seat which is adjustable, resilient or yielding in such a way that the angle of the seat may optionally incline somewhat backwards at the rear edge in order to bring the torso out of balance and come into imbalance backwards, this automatic exercise effect will be capable of being achieved as desired.

The chair seat or seating device does not initially need to be constructed so as to be capable of tilting or inclining backwards. It may optionally be adjustable at the rear edge

so that one can allow it to incline backwards a certain number of degrees as desired. It is also conceivable that the seat may have a resilient movement each time the user moves, possibly to the sides, but preferably backwards. The seat will then rock and create imbalance for the chair user. This will cause the chair user to increase his use of muscles in the abdominal wall to a considerable extent, and the user must then, in order to maintain bodily balance in a sitting position, increase his use of the abdominal, pelvic, femoral and back musculature in the same way as during sit-ups.

Because the present invention permits a moveable seat, this will cause the chair user to display movement and activity, and will also contribute to the creation of variation and circulation for the spinal column, thereby achieving a more beneficial physiological functional improvement in comparison with that which is known in customary sitting postures. Amongst other things, the increased movement of the seat will result in increased joint movement and thus increased diffusion in the cartilaginous discs. This also gives rise to increased blood circulation in and exercise of the muscles along the spinal column.

The present inventive concept is thus a rest device for use with a chair or seating means to provide exercise for the abdominal, pelvic, femoral and back muscles.

By using the ventral leg rest below the knee, most muscles in the calves, the thighs and the pelvic, back and stomach region will benefit from good exercise effect. A ventral leg rest above the knee, i.e. , a thigh rest will however provide a more pronounced exercise effect for the musculature of the abdominal wall because the balance of the body, as mentioned, must be maintained by means of fewer muscles groups. By using a support against the thighs, the sartorius, tensor fascia lata, gracilis and a part of the large quadriceps femoris

group will not be used to the same extent, but on the other hand the load will be transferred to the adductor group between the thighs and the pelvis and the abdominal group between the pelvis and the thorax, and especially the rectus abdominus, but also the psoas and iliacus will receive a greater load. The load on the quadratus lumborum with the sacrospinalis and erector spinae groups which do most of the work in holding the actual spinal column straight, will be about the same whether one uses a ventral leg rest against the thighs or below the knee.

The support against the thighs in combination with a backwardly inclining and yielding seat will not only exercise and slim down (tauten) the abdominal muscles, but as mentioned will also increase the load on the psoas muscles. These major posture muscles will not only be exercised but will also increase even more the curve of the lumbar region in a sitting position. This is a great advantage for a posturally correct sitting position.

In a usual sitting posture one loses the curve of the lumbar region and the body posture becomes more stooping. A stooping posture of this kind redistributes the weight of the body in relation to its weight-bearing axis (spinal column) , and the load increases thereby pressing on and into the cartilaginous discs (discus) in the spinal column. This is, of course, more wearing on the back. A thigh rest will thus help to correct this condition and will also give the user the correct feeling of having a good curve in the lumbar region and a tautening of the stomach muscles.

During practical tests of the present invention, it has been found advantageous to manufacture the seat of the seating device or chair with a backwardly tilting mechanism or springing, where the back edge of the seat will tilt within a range of 2 to 30 cm. A balanced exercise effect for a man

weighing 100 kg would be achieved with a springing which is- at least 12 to 15 cm, depending upon how straight he sits on the chair. A correspondingly good effect for a woman weighing 50 kg would be achieved with a spring suspension which is at least 5 to 8 cm, somewhat dependent upon how much she leans backwards. The intrinsic resistance of the seat against tilting movement will in a known way per se be capable of being pre-set by means of an adjustable pre-tensioning means, e.g., a spring or by determining the resilience and springing of the chair material in relation to the stucture, its thickness and its width. With a person weighing 100 kg a minimum springing/tilting of the back edge of the seat ought to be 2 cm, although preferably at least 10 to 12 cm to be able to create sufficient imbalance in the seat to give an adequate exercise effect.

Even though in the embodiment in Fig. 12 two runners 25; 26 are shown which are constructed in an upward direction and uppermost become thigh rests 30; 31, it will immediately be understood that thigh rests may project upwards from the sides of the chair support or seat. Optionally, it is conceivable that the thigh rest is almost T-shaped and projects up from the front of the chair support or seat.