[0001] The present invention relates to an exercise machine utilising the weight of the
               user as a source of resistance for exercise.
 
            [0002] Many such machines are known in the prior art: 
US 6,244,995, for instance, discloses an exercise machine in which a carriage is movably mounted
               on a concave-up curved track. A user lies on the carriage and then exercises by means
               of pushing and/or pulling against various handles, footrests, pulleys, etc, causing
               the carriage to rise up the curved track. The resistance to the exercise movement
               at any given point on the track is proportional to the weight of the user and to the
               sine of the angle of the tangent to the track at that point. Since the curvature of
               the track is concave-up, i.e. concave with respect to the carriage, the resistance
               increases as the exercise movement progresses. The intensity of the resistance profile
               (i.e. the resistance to exercise in dependence of position along the track) may be
               varied by adjusting the angle of the track.
 
            [0003] This resistance profile is particularly suited to press exercises such as leg presses.
               However, when used with certain pulling exercises, it may overstress the muscle groups
               being exercised, potentially causing injury, and it may also present such a degree
               of resistance that certain exercise movements cannot be performed to completion.
 
            [0004] The object of the invention therefore is to provide an exercise machine of the above-mentioned
               type exempt from the above-mentioned problems, and thereby enable optimal exercising
               with a greater variety of exercises than is possible with the exercise machine of
               
US 6,244,995.
 
            [0005] This object is achieved by an exercise device comprising:
               
               
                  - at least one curved track comprising a first section with curvature (κ1) of a first sign, that is to say the least one curved track curves in a first direction,
                     i.e. is either concave or convex, or in other words curves either up or down. By "curvature
                     of a first sign", the meaning of "sign" is meant in its mathematical sense, i.e. κ1>0 [positive sign] or κ1<0 [negative sign], as is discussed in greater detail below.
 
                  - a carriage mounted movably on the at least one track and adapted to support the body
                     of a user, upon which the user can sit, kneel or lie when using the exercise device.
 
               
 
            [0006] According to the invention, the curved track further comprises a second section with
               curvature (κ
2) of opposite sign to the first curvature (if the curvature of the first section k1<0
               [negative sign] then curvature of the second section k2>0 [positive sign] and vice-versa),
               i.e. of opposite curvature thereto, the second section following the first section,
               i.e. adjacent thereto or separated by an extra connecting section which may be straight
               or even curved in a different manner to the first and the second sections. In other
               words, the track presents a dual curvature, this dual curvature being thus "s" or
               "reverse-s" shaped. It should be noted that the two curvatures κ
1, κ
2 do not have to be constant, i.e. do not have to represent circular arcs.
 
            [0007] As in the prior art, the section of the track having a curvature which causes increasing
               resistance as an exercise motion progresses, i.e. the "concave up" section, is optimal
               for press exercises such as leg presses, bench presses and so on. Advantageously,
               the section with the opposite curvature, i.e. the section with "convex up" curvature,
               is optimal for pulling exercises such as a row, chin-ups, pulldowns, leg curls, tricep
               extensions and so on. This is because, on the "convex up" curvature, as the exercise
               movement progresses, the resistance decreases, enabling the exercising to take place
               with an appropriate resistance profile, reducing the risk of injury. As a result,
               a greater variety of exercise movements can be carried out in an optimal fashion on
               a single exercise device than is possible with prior art exercise devices.
 
            [0008] In an embodiment, one of the first section and the second section is concave with
               respect to the carriage, and the other of the first section and the second section
               is convex with respect to the carriage. Preferably, the first curvature is concave
               with respect to the carriage, and the second curvature is convex with respect to the
               carriage.
 
            [0009] In an embodiment, the second section is adjacent to the first section, i.e. the two
               sections are contiguous and adjoining, which permits a rapid transition from increasing
               resistance to decreasing resistance as the carriage travels along the track.
 
            [0010] In an embodiment, the first section, the second section, or both describe circular
               arcs, i.e. follow the arc of a circle. This enables simple manufacture since circular
               arcs have a constant curvature and thus easy to manufacture.
 
            [0011] In an embodiment, the magnitude of the curvature of the second section (|κ
2|) is greater than the magnitude of the curvature of the first section (|κ
1|), i.e. |κ
2| > |κ
1|. In other words, the second section has a tighter curvature than the first section,
               and thus the change in resistance as an exercise progresses happens more rapidly.
               This is particularly advantageous in the case in which the second section has a convex
               curvature with respect to the carriage and is used for pulling-type exercises such
               as chin-ups. The resistance profile for such exercises can thus be tailored independently
               of the resistance profile for exercises taking place on the first section, such as
               leg presses.
 
            [0012] In an embodiment, a foot rest is provided at or in proximity to the free end of the
               first section. The footrest can be provided joined directly to the track at the free
               end of the first section, or to supporting frame to which the track is mounted. Since
               a footrest by definition has to be suitable for a user to rest his or her foot or
               feet thereupon, the first section is thus defined as the lower section in the orientation
               which the exercise device will take when in use, i.e. the first section is the section
               nearest the ground.
 
            [0013] In an embodiment, the exercise device further comprises a support structure, such
               as a support frame, for supporting the track and hinged thereto at or proximate to
               the free end of the first section. This enables the inclination of the track to be
               varied, and thereby the intensity of the resistance profile and thus the intensity
               of exercises performed on the exercise device to be adjusted, since the track can
               thus be rotated about the hinge.
 
            [0014] In an embodiment, the first section is longer than the second section, which enables
               the relation between the length of track available for an exercise being performed
               on the first section to be tailored with regard to that being performed on the second
               section. Preferably, the length of the second section is between 30% and 70%, preferably
               between 40% and 60%, further preferably between 45% and 55% of the length of the first
               section.
 
            [0015] In an embodiment, the track is a solid structure comprising: at least one tube with
               round, oval, or square structure; or a flat track with at least one flange; or at
               least one V-groove track; or at least one girder-type track. These provide various
               forms for the track.
 
            [0016] The invention will be further described with relation to nonlimiting embodiments
               illustrated in the figures, which show:
               
               
Figure 1: a schematic representation of the mechanical principle behind the invention;
               Figure 2: an illustration of the concept of curvature as it applies to the exercise
                  device of the invention;
               Figure 3: a schematic graph of the curvature k of the curve ABC of figure 2;
               Figure 4: a schematic representation of an exercise device constructed according to
                  the invention, at the start of a leg-press exercise;
               Figure 5: a schematic representation of the situation at the end of a leg-press exercise;
               Figure 6: a schematic representation of the situation at the start of a chin-up exercise;
               Figure 7: a schematic representation of the situation at the end of a chin-up exercise;
               Figure 8: a schematic graph of a resistance profile for an exercise device according
                  to the invention.
 
            [0017] In the figures, like reference signs represent like parts.
 
            [0018] Figure 1 shows in schematic form the mechanical principle exploited by the invention.
               Curved track 1, here represented by a single line of constant radius (i.e. an arc
               of a circle), has a carriage 2 rolling thereupon by means of rollers 3a, 3b. The weight
               of a user and the weight of the carriage together are represented in figure 1 by force
               arrow mg. Tangent T is tangential to curved track 1 at a point equidistant between
               rollers 3a, 3b, and makes an angle θ With the horizontal. Ignoring friction and assuming
               that the user effectively applies a force F at a point on carriage 2 equidistant between
               the rollers 3a, 3b and tangential to the carriage 2, to balance the forces and thus
               overcome the resistance due to gravity, the magnitude of force F is given by: 

 
            [0019] Thus, as θ increases, e.g. as carriage 2 moves up curved track 1, F and thus the
               resistance to exercise increases, and likewise, as θ decreases, e.g. as carriage 2
               moves down curved track 1, F and thus the resistance to exercise decreases.
 
            [0020] Figure 2 illustrates the concept of curvature as it applies to the present invention.
               In this figure, track 1 is schematically represented by a curve ABC of dual curvature
               passing through points A, B and C. The section AB is considered here as being a first
               section, and the section BC is considered as being a second section. In both of the
               first section and the second section, the curve follows an arc of a circle of radius
               R
1, R
2 respectively. The relation between R
1 and R
2 has been exaggerated for the purposes of illustration. In this case, Curvature κ
               in its most general, scalar, form is defined as the inverse of the radius R, i.e.:
               

 
            [0021] The curvature of the first section AB is thus: 

 and the curvature of the second section BC is thus: 

 
            [0022] In the more complex case of a non-circular curve, the curvature κ at any given point
               is given by the inverse of the radius of curvature at that point.
 
            [0023] However, simple scalar curvature is insufficient to adequately express the S-shaped
               track of the invention, thus the concept of signed curvature must be introduced to
               distinguish between convex and concave curves. Mathematically, to determine signed
               curvature, the curve must be parametrised and expressed as a function of a parameter.
               The sign of the signed curvature κ indicates the direction in which the unit tangent
               vector rotates as a function of the parameter along the curve: if the unit tangent
               T rotates anticlockwise, then κ > 0 (positive sign), whereas if the unit tangent T
               rotates clockwise, then κ < 0 (negative sign). Since any given curve can be parametrised
               in opposite orientations, the definition of positive and negative curvature thus depends
               on the particular parametrisation chosen, in the same way that concave and convex
               depends on the frame of reference chosen. In more simple terms, the sign of the curvature
               κ can be determined by looking at on which side of the curve the centre of the radius
               of curvature lies and defining one side of the curve as "positive" and the other side
               as "negative".
 
            [0024] In relation to the illustration of figure 2, the curvature of curve ABC can be described
               as follows:
               
               
                  - 1. By parametrisation:
                     
                     
Curve ABC is parametrised such that as the parameter increases, the curve is described
                        from A, through B, to C. Thus, as the parameter increases, unit tangent T rotates
                        anticlockwise from A to B, and then rotates clockwise from B to C. Thus in this frame
                        of reference, κAB = 1 / R1, and κBC = -1 / R2. At the point of inflection B, κB = 0, since at that point the unit tangent vector is not rotating. In the case of
                        the opposite parametrisation, the opposite relations will hold, reversing the signs
                        of the curvatures.
                   
                  - 2. Position of the centre of the radius of curvature:
                     
                     
Defining the centre of the radius of curvature as being "above" the curve as it is
                        illustrated in figure 2, it is self-evidently clear that κAB = 1 / R1, and κBC = -1 / R2, and at the point of inflection B, κB = 0. Likewise defining the frame of reference in the opposite manner reverses the
                        signs of the curvatures.
                   
               
 
            [0025] Figure 3 illustrates a qualitative, not to scale graph of the curvature κ of the
               curve ABC of figure 2. The horizontal axis represents the distance d along the curve
               and the vertical axis represents the signed curvature κ of the curve. Exactly at the
               point B, curvature κ is zero.
 
            [0026] In qualitative terms, the curvature can also be described as follows:
               
               
In the view of figure 2, defining "up" as it is presented in the figure, the first
                  section of the curve (AB) as illustrated may be described as "concave up" or "convex
                  down", and likewise the second section of the curve (BC) may be described as "convex
                  up" or "concave down".
 
            [0027] Alternatively, the curvature may be referenced to the carriage 2. In this case, in
               the illustrated situation, the first section of the curve (AB) is concave with respect
               to the carriage 2, and the second section of the curve (BC) is convex with respect
               to the carriage 2.
 
            [0028] Additionally, the overall shape of curve ABC can be described as "S-shaped", whereas
               its mirror image can be described as "reverse-S-shaped".
 
            [0029] Figure 4 illustrates schematically an exercise device constructed according to the
               invention. Curved track 1 is mounted on a support structure 4 which may be of any
               type. In the illustration, the bottom free end of curved track 1 is hinged to the
               support structure 4 at hinge 5. The curved track 1 is further supported by non-illustrated
               supporting means which preferably permit the angle of the curved track 1 to be varied.
               While the curved track 1 is schematically illustrated in figure 4 as a single track,
               it may be of any conventional type such as a flat track with at least one flange,
               a V-groove track, a single girder-type track, multiple tubular tracks, multiple-groove
               or girder-type tracks or similar. See, for instance, 
US 4,176,836, 
US 6,244,995 and 
US 2002/0132706 for examples.
 
            [0030] Carriage 2 is mounted movably on curved track 1 so as to permit the carriage 2 to
               move along the curved track 1, e.g. by means of rollers illustrated as 3a and 3b.
               The skilled person understands how to arrange the carriage 2 on any given track arrangement
               to permit it to move along the track but not to fall off, e.g. by means of opposed
               rollers, rollers arranged in grooves in the track(s) and so on: this need not be discussed
               further.
 
            [0031] Carriage 2 is shaped so as to support the body of a user of the exercise device,
               and should preferably be able to support the user's body in a near-vertical position.
 
            [0032] A foot rest 6 is provided, illustrated as being attached to a point close to the
               bottom end of the track 1, however foot rest 6 may be arranged in any convenient manner,
               e.g. on support structure 4. Furthermore, various handles, bars, pulley systems and
               so on (not illustrated) may be provided as required to permit a range of exercises
               to be performed on the exercise device. Examples of such handles etc. are illustrated
               e.g. in 
US 6,244,995, and need not be discussed further.
 
            [0033] Curved track 1 is divided into a first section AB extending from point A to point
               B, and a second section BC extending from point B to point C. The track 1 may be constructed
               in a single piece or multiple pieces as required. The track 1 is terminated by an
               optional end cap 7. In the illustrated embodiment, the first section is at the lower
               end of track 1, nearest the ground, when the exercise device is in its position of
               use, and the second section is at the upper end of track 1. As a possible variation,
               an extra section, e.g. a straight section, may be included between the first section
               and the second section. As illustrated, the first section from A to B is concave with
               respect to the carriage 2, i.e. has "concave up", or "positive" curvature (κ>0) as
               defined above in reference to figure 2. User 10 is illustrated in figure 4 as being
               in start position for a leg press exercise, with his feet resting on foot rest 6.
               Due to the aforementioned positive curvature, as the user performs the leg press exercise,
               the carriage 2 will rise up the curved track 1 at an ever-increasing angle, thus the
               resistance to the exercise will increase until the point at which the exercise is
               complete, as illustrated in figure 5. Although in figure 5 the upper roller 3b has
               transitioned onto the second section of the curved track 1, the angle of travel of
               the carriage has increased up to the position illustrated in figure 5.
 
            [0034] In the illustrated embodiment, the second section BC of the curved track 1 has the
               opposite curvature to the first section AB, i.e. has a "convex up", or "negative"
               (κ<0) curvature as defined as above. The overall curve ABC as illustrated goes through
               a point of inflection at point B, i.e. there is no discontinuity in the curve ABC
               that would cause the user to experience a "bump" in the transition from the first
               section AB to the second section BC. Figures 6 and 7 illustrate how the second section
               BC is used during a chin-up exercise. Figure 6 shows the situation at the start of
               the chin-up exercise. User 10 holds at least one handle or bar represented schematically
               at 8 as being attached to the free end of curved track 1, although they may be attached
               in any convenient manner e.g. to a support frame (not illustrated). Pulling on the
               handle or bar 8 with sufficient force to overcome gravity causes carriage 2 to move
               up onto the second section BC up to the position illustrated in figure 7 which represents
               the end of the exercise. As the carriage rises from the position illustrated in figure
               6 to that illustrated in figure 7, the angle of travel of the carriage reduces, thereby
               reducing the resistance to the exercise. This provides a more optimal resistance profile
               through the illustrated exercise movement for a pulling-type exercise such as the
               illustrated chin-up exercise.
 
            [0035] Figure 8 shows schematically a graph of the resistance profile dependent on carriage
               position along the track for an exercise device of the type and general arrangement
               of that illustrated in figures 4-7. From position 81 to position 82, the resistance
               increases due to the track being concave with respect to the carriage; from position
               82 to position 83 the resistance decreases due to the track being convex with respect
               to the carriage. The exact shape of the resistance curve 80 and the exact locations
               of positions 81, 82, and 83 depend on the shape of the curved track 1, the design
               of the carriage 2, and the position of footrests, bars, handles, etc. In principle,
               the region from position 81 to position 82 is particularly suited for pushing-type
               exercises like the leg-press exercise illustrated in figures 4 and 5, and the region
               from position 82 to position 83 is particularly suitable for pulling exercises such
               as a row, chin-ups, pulldowns, leg curls, tricep extensions and so on. If desired,
               particular exercises may involve overlapping at least part of both regions.
 
            [0036] The skilled person can choose the exact shape of the curved track 1, the lengths
               of the first and second sections, and position of handles, bars, pulleys etc to suit
               the user, and to engineer the exercise device for desired resistance profiles for
               various exercises. In the illustrated example, both the first section AB and the second
               section BC are conformed as arcs of circles, meeting tangentially at B. However, other
               curved shapes are possible, such as x
2, exponential, logarithmic, sections of sinusoids, and so on as desired. In the embodiment
               illustrated in figures 4-7, the curvature of the second section BC of curved track
               1 is greater than that of the first section AB, and the length of the second section
               BC is approximately 50% of that of the first section AB. Alternatively, both sections
               may be of the same length, or the second section may be longer than the first section.
 
            [0037] As a further alternative, although the lower section AB of curved track 1 has been
               illustrated as being concave with respect to carriage 2 and the upper section BC of
               curved track 1 has been illustrated as being convex with respect to carriage to 2,
               the opposite arrangement is also possible if desired, i.e. the first, lower section
               AB being convex with respect to carriage 2 and the second, upper section BC being
               concave with respect to carriage 2.
 
            [0038] Although the invention has been described above in terms of specific embodiments,
               variations thereto are possible while still remaining within the scope of the appended
               claims.
 
          
         
            
            1. Exercise device comprising at least one curved track (1) comprising a first section
               (AB) with curvature of a first sign, a carriage (2) mounted movably on the at least
               one track (1) and adapted to support the body of a user (10), characterised in that the curved track (1) comprises a second section (BC) with a curvature of opposite
               sign to the first sign, the second section (BC) following the first section (AB),
               wherein the dual curvature is "S" or "reverse-S" shaped, and has an inclination, and
               a magnitude of the curvature of the second section (BC) is greater than a magnitude
               of the curvature of the first section (AB), wherein, when the exercise device is in
               its position of use, the first section is at a lower end of the track (1), nearest
               the ground, and the second section is at an upper end of the track (1), whereby a
               resistance to an exercise movement depends on a carriage position along the track
               (1), and the weight of the user.
 
            2. Exercise device according to the preceding claim, wherein one of the first section
               (AB) and the second section (BC) is concave with respect to the carriage (2), and
               the other of the first section (AB) and the second section (BC) is convex with respect
               to the carriage (2).
 
            3. Exercise device according to claim 1, wherein the first section (AB) is concave with
               respect to the carriage (2), and wherein the second section (BC) is convex with respect
               to the carriage (2).
 
            4. Exercise device according to any preceding claim, wherein the second section (BC)
               is adjacent to the first section (AB).
 
            5. Exercise device according to any preceding claim, wherein the first section (AB) and/or
               the second section (BC) describe circular arcs.
 
            6. Exercise device according to any preceding claim, further comprising a footrest (6)
               provided at or in proximity to the free end of the first section (AB).
 
            7. Exercise device according to any preceding claim, further comprising a support structure
               (3) for supporting the track and hinged thereto at or proximate to the free end of
               the first section (AB).
 
            8. Exercise device according to any preceding claim, wherein the first section (AB) is
               longer than the second section (BC).
 
            9. Exercise device according to the preceding claim, wherein the length of the second
               section (BC) is between 30% and 70%, preferably between 40% and 60%, further preferably
               between 45% and 55%, of the length of the first section (AB).
 
            10. Exercise device according to any preceding claim, wherein the track (1) is a solid
               structure comprising: at least one tube with round, oval, or square structure; or
               a flat track with at least one flange; or at least one V-groove track; or at least
               one girder-type track.
 
          
         
            
            1. Übungsgerät umfassend zumindest eine Kurvenbahn (1) umfassend einen ersten Abschnitt
               (AB) mit einer Krümmung eines ersten Vorzeichens, einen beweglich montierten zur Unterstützung
               des Körpers eines Benutzers (10) geeigneten Wagen (2) auf der zumindest einen Bahn
               (1), dadurch gekennzeichnet, dass die Kurvenbahn (10) einen zweiten Abschnitt (BC) mit einer Krümmung eines entgegengesetzten
               Vorzeichens zum ersten Vorzeichen umfasst, der zweite Abschnitt (BC) dem ersten Abschnitt
               (AB) folgt, wobei die doppelte Krümmung "S-" oder "verkehrt S-" förmig ist und eine
               Neigung aufweist, und eine Stärke der Krümmung des zweiten Abschnitts (BC) größer
               ist als die Stärke der Krümmung des ersten Abschnitt (AB), wobei, wenn das Übungsgerät
               in Gebrauchsposition ist, der erste Abschnitt an einem tiefer gelegenen Ende der Bahn
               (1), nächst dem Boden, und der zweite Abschnitt an einem oberen Ende der Bahn (1)
               ist, wobei ein Wiederstand gegen eine Übungsbewegung von der Position des Wagens entlang
               der Bahn (1) und dem Gewicht des Benutzers abhängt.
 
            2. Übungsgerät entsprechend dem vorhergehenden Anspruch, wobei einer, der erste Abschnitt
               (AB) oder der zweite Abschnitt (BC), bezüglich des Wagens (2) konkav ist und der andere,
               erste Abschnitt (AB) oder zweite Abschnitt (BC), konvex bezüglich des Wagens (2) ist.
 
            3. Übungsgerät entsprechend Anspruch eins oder zwei, dadurch gekennzeichnet dass der erste Abschnitt (AB) konkav bezüglich des Wagens (2) ist, wobei der zweite Abschnitt
               (BC) konvex bezüglich des Wagens (2) ist.
 
            4. Übungsgerät entsprechend einem der vorhergehenden Ansprüche, wobei der zweite Abschnitt
               (BC) an den ersten Abschnitt (AB) anschließt.
 
            5. Übungsgerät entsprechend einem der vorhergehenden Ansprüche, wobei der erste Abschnitt
               (AB) und/oder der zweite Abschnitt (BC) kreisförmige Bögen beschreiben.
 
            6. Übungsgerät entsprechend einem der vorhergehenden Ansprüche, weiter eine Fußrast (6)
               umfassend, die an oder in der Nähe des freien Endes des ersten Abschnitts (AB) vorgesehen
               ist.
 
            7. Übungsgerät entsprechend einem der vorhergehenden Ansprüche, weiter eine Stützstruktur
               (3) zum Stützen der Bahn umfassend und an dieser an dem oder in der Nähe des freien
               Endes der ersten Sektion (AB) schwenkbar befestigt.
 
            8. Übungsgerät entsprechend einem der vorhergehenden Ansprüche, wobei der erste Abschnitt
               (AB) länger als der zweite Abschnitt (BC) ist.
 
            9. Übungsgerät entsprechend dem vorhergehenden Anspruch, wobei die Länge des zweiten
               Abschnitts (BC) zwischen 30 % und 70 %, bevorzugt zwischen 40 % und 60 %, weiter bevorzugt
               zwischen 45 % und 55 %, der Länge des ersten Abschnitts (AB) beträgt.
 
            10. Übungsgerät entsprechend einem der vorhergehenden Ansprüche, wobei die Bahn (1) eine
               stabile Struktur ist, umfassend: zumindest ein Rohr mit runder, ovaler oder quadratischer
               Struktur; oder einer flachen Bahn mit zumindest einem Flansch; oder zumindest eine
               V-förmige Bahn; oder zumindest eine trägerartige Bahn.
 
          
         
            
            1. Appareil d'exercice comprenant au moins un rail incurvé (1) comprenant une première
               section (AB) avec une courbure d'un premier signe, un chariot (2) monté de façon mobile
               sur le au moins un rail (1) et adapté pour supporter le corps d'un utilisateur (10),
               caractérisé en ce que le rail incurvé (1) comprend une seconde section (BC) avec une courbure de signe
               opposé au premier signe, la seconde section (BC) suivant la première section (AB),
               dans lequel la double courbure forme un « S » ou un « S inversé » et est inclinée,
               et la grandeur de la courbure de la seconde section (BC) étant supérieure à la grandeur
               de la courbure de la première section (AB), dans lequel, lorsque l'appareil d'exercice
               est dans sa position d'utilisation, la première section se trouve à une extrémité
               inférieure du rail (1), à proximité du sol, et la seconde section se trouve à une
               extrémité supérieure du rail (1), la résistance à un mouvement d'exercice dépendant
               de la position du chariot le long du rail (1) et du poids de l'utilisateur.
 
            2. Appareil d'exercice selon la revendication précédente, dans lequel l'une de la première
               section (AB) et de la seconde section (BC) est concave par rapport au chariot (2),
               et l'autre de la première section (AB) et de la seconde section (BC) est convexe par
               rapport au chariot (2).
 
            3. Appareil d'exercice selon la revendication 1, dans lequel la première section (AB)
               est concave par rapport au chariot (2), et dans lequel la seconde section (BC) est
               convexe par rapport au chariot (2).
 
            4. Appareil d'exercice selon l'une des revendications précédentes, dans lequel la seconde
               section (BC) est adjacente à la première section (AB).
 
            5. Appareil d'exercice selon l'une des revendications précédentes, dans lequel la première
               section (AB) et/ou la seconde section (BC) décrivent des arcs circulaires.
 
            6. Appareil d'exercice selon l'une des revendications précédentes, comprenant en outre
               un repose-pied (6) prévu au niveau de ou à proximité de l'extrémité libre de la première
               section (AB).
 
            7. Appareil d'exercice selon l'une des revendications précédentes, comprenant en outre
               une structure de support (3) pour supporter le rail et qui y est articulée au niveau
               de ou à proximité de l'extrémité libre de la première section (AB).
 
            8. Appareil d'exercice selon l'une des revendications précédentes, dans lequel la première
               section (AB) est plus longue que la seconde section (BC).
 
            9. Appareil d'exercice selon la revendication précédente, dans lequel la longueur de
               la seconde section (BC) est comprise entre 30 % et 70 %, de préférence entre 40 %
               et 60 %, de façon davantage préférée entre 45 % et 55 % de la longueur de la première
               section (AB).
 
            10. Appareil d'exercice selon l'une des revendications précédentes, dans lequel le rail
               (1) est une structure solide comprenant au moins un tube de structure ronde, ovale
               ou carrée, ou un rail plat avec au moins une bride, ou au moins un rail avec une rainure
               en V, ou au moins un rail de type poutre.