FR2829700A1 - Tennis racket player play sequence movement analysis having movement detector with three plane static accelerometers measuring movement and transmitter transmitting movement size signals function measured components. - Google Patents

Abstract

Tennis racket player sequence movement analysis having movement detector with three plane static accelerometer measuring movement and transmitter transmitting movement size signals function measured components.

Description

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 The present invention relates to a sports article such as a tennis racket, comprising at least one movement detector.

 International device WO 99 26 704 discloses a device for detecting the movements of a part of the body during physical activity. This device comprises a detector which can be provided with a plurality of accelerometers sensitive to movement in different planes, the data being able to be transmitted to a microprocessor located remotely by using for example radio waves, for analysis and storage. of this data. The detector is housed in a substantially parallelepiped housing intended to be fixed on a part of the body. Such a housing is not suitable for being fixed for example on a tennis racket, and moreover, is relatively bulky.

 Also known from European patent application EP 0 098 519 is a device equipping a tennis racket, making it possible to inform the player when the latter commits an error by completing a sequence of play. This device can be put in place removably on the racket's handle or integrated into it. It contains balls, the displacement of which in suitable slides makes it possible to detect the movement of the racket. This known device is also arranged to record signals relating to a game sequence and to display information obtained from these signals by means of a display system located on the racket. Such a device does not allow an in-depth analysis of the player's technique, in particular to determine if progress has been made from one training session to the next. In addition, fixing the device on the handle can hinder the grip of the racket by the player or, if the device is integrated into the handle, make the racket relatively complex and expensive.

 The present invention aims in particular to facilitate the analysis of a game sequence of a player practicing a sport, for example tennis.

 It achieves this by means of a sports article such as a tennis racket, comprising a motion detector comprising at least three static accelerometers capable of measuring components of the movement of the article along three distinct axes, and a transmitter capable of transmitting. signals representative of at least one magnitude of the movement, these signals being a function of the components thus measured.

 The signals emitted by the motion detector can be processed on a

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 device separate from it, which makes it possible to lighten the motion detector and reduce its size, which can thus become sufficiently low so that its air resistance remains negligible and does not adversely affect the quality of the player's shots .

 Preferably, the motion detector comprises three accelerometers whose axes are orthogonal two by two.

 When the article consists of a tennis racket, one of the accelerometers is advantageously arranged to measure a component of the movement along a parallel or coincident axis with the axis of the handle of the racket.

 Preferably, the motion detector comprises a housing, for example made of plastic.

 This housing is preferably shaped, when the article is constituted by a tennis racket, to be fixed at the branches of the frame of the racket, in particular at the junction of its branches.

 Thus, the motion detector can easily adapt to a standard racket and does not interfere with the grip.

 In addition, the contact of the housing with the two branches of the frame allows reliable retention of the motion detector on the racket and positioning of the accelerometers near the axis of the handle, which in particular allows precise measurement of the acceleration in particular along the axis of the racket.

 The presence of the motion detector near the handle also makes it possible not to excessively increase the inertia of the racket.

 The location of the housing between the branches of the frame also offers the advantage of limiting the exposure of the detector to bullet impacts liable to damage it.

 In an exemplary implementation of the invention, the housing is fixed to the racket using means capable of damping the vibrations of the racket, these means being able in particular to include a block of foam.

 The housing may include a stud capable of engaging between the branches of the racket frame, this stud preferably being secured to a block of foam shaped to be housed between said branches.

 The foam block makes it possible to reduce the vibrations generated in the racket during a ball impact and to limit the transmission of these to the motion detector.

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 The foam block can have deformation properties allowing it to be fixed, without appreciable play, on racket frames having different geometries.

 In addition, the housing can be arranged so as to allow the replacement of the foam block, in particular when this block has undergone some wear or when it has to be replaced by another foam block suitable for a particular racket.

 Advantageously, the housing comprises two parts, each in the general shape of a half-shell, preferably being assembled in a removable manner.

 One of the parts of the housing may comprise a first fixing member and the other part a second fixing member, capable of cooperating with the first fixing member during the assembly of the two parts, the first and second fixing members can for example be shaped to cooperate by screwing or snap-fastening.

 The casing can be held on the article by means of a strap or tabs encircling the casing and comprising fixing means of the Velcro type.

 It is thus possible to set up the motion detector on the article in a relatively simple manner.

 In addition, it is not necessary to provide specific fixing means on the article and the detector can thus be fixed on the article only during training, for example.

 Maintaining the case on the article can also be ensured by an elastic strap in which case the case advantageously comprises an external groove in which said strap can be housed.

 In a particular implementation of the invention, the box houses at least two electronic cards, one of them carrying two accelerometers and the other carrying a third accelerometer, these two cards being arranged perpendicularly.

 The housing can also accommodate a third card fixed perpendicular to one of the two aforementioned cards and on which is mounted a transmitter.

 As a variant, the three accelerometers are mounted on the same electronic card and one of the accelerometers is mounted in the direction of the thickness of the card, through the latter, which makes it possible to produce the electronic card with a reduced bulk.

 The transmitter may be capable of transmitting the above-mentioned signals in the form of waves

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 radio frequency.

 Alternatively, the signals can be transmitted using an infrared transmitter.

 The signals transmitted are advantageously compressed and coded prior to their transmission, which accelerates the transfer of useful information and makes it possible to reduce the risk of interference when several players each use, in the same zone, a motion detector according to the invention. .

 The housing may include an internal connector making it possible both to mechanically join the two parts of the housing and to ensure the electrical connections between the various electronic cards.

 The connector may include a wall in which are arranged conductors ensuring the electrical supply of electronic cards and the transmission of data, in particular in digital form, between the cards.

 These conductors are for example six in number, four conductors ensuring the transmission of data and two conductors ensuring the electrical supply.

 The connector can be hollow and define a compartment allowing to house a source of electrical energy such as a battery or an accumulator.

 As a variant, the housing may include slides allowing it to slide on the branches of the racket frame until its final position between these branches, at the junction of these. The housing can be retained in this position for example by friction of the slides on the arms of the racket. In this case, the housing can be shaped so as not to protrude from the space between the branches or to protrude only slightly therefrom.

 In an exemplary implementation of the invention, the motion detector is integrated in the handle of the racket.

 The motion detector advantageously comprises a reception module which makes it possible to receive an acknowledgment of the good transmission of the signals transmitted by the transmitter.

 Such a reception module can also receive instructions for controlling the operation of the detector, for example to switch it on or off, and to program certain functions.

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 Thanks to the presence of this reception module, the motion detector can be devoid of any control button on the outside, or have a reduced number thereof, which is favorable for good sealing of the case.

 Another subject of the invention is a motion detector able to be mounted on a tennis racket, comprising a handle connected to a sieve by two branches, this detector comprising three accelerometers making it possible to measure components of the movement of the racket according to three separate axes, the detector further comprising a transmitter capable of transmitting signals representative of at least one magnitude of the movement obtained from the components of the movement measured, the detector comprising a housing formed in particular by two parts capable of being assembled, this housing being able to be fixed on the racket at the level of the two branches.

 The invention also relates to a system for assisting in the practice of a sport such as tennis, comprising a movement detector mounted on a sporting article such as a tennis racket, this detector comprising three accelerometers making it possible to measure components of the movement of the article along three distinct axes, the detector comprising a transmitter capable of transmitting signals representative of a magnitude of the movement obtained from the components thus measured, this system further comprising a receiver capable of receiving signals transmitted by the transmitter and a storage space for storing data relating to these signals.

 Such a storage space can be constituted for example by a hard disk, a floppy disk, an integrated circuit or an optical disk.

 Advantageously, the receiver is connected to a processing unit such as a computer capable of supplying, from the signals received by the receiver, information, in particular in the form of curves and / or tables, allowing the analysis of sequences of game completed by the player.

 The receiver can only be arranged to receive and transfer the signals to a computer without storing them, which simplifies its design.

 As a variant, the receiver may include signal processing means and / or display means making it possible, from the received signals, to view information, in the form of curves and / or tables for example, without having to link the receiver to a computer.

 The receiver can be made up of a mobile phone or an organizer

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 electronics arranged to receive and optionally store the aforementioned signals.

 The receiver and / or the computer to which the receiver is connected if necessary can be connected remotely to a computer server, via a network such as the Internet.

 The invention also relates to a diagnostic method for the practice of a sport such as tennis, comprising the following steps: - performing at least one game sequence with a sporting article such as a tennis racket, the latter comprising a motion detector comprising three accelerometers making it possible to measure components of the movement of the article along three different axes, - transmitting to a receiver by means of a transmitter placed in the motion detector signals representative of at least one magnitude of movement obtained from the measured components, the receiver being arranged to receive and store said signals or transfer them to a storage space, - process said signals using a processing unit so as to establish a diagnosis on the sequence of play executed.

 Thanks to the invention, it is possible to store different diagnoses of the same player corresponding to different training sessions in order to assess the progress made by the player from one session to the next.

 We can also compare the diagnosis established for one player with that established for another player in order to assess the strengths and weaknesses of one compared to the other.

 It is also possible, on the basis of such a diagnosis, to establish a training program for a player, this training program possibly comprising physical monitoring, psychological monitoring and technical monitoring.

 The aforementioned processing unit can be a computer on which a program intended to establish a diagnosis is run on the basis of the signals received from the motion detector.

 This program can be available initially on a support separate from the computer, a CD for example, which one loads on the computer or, as a variant, this program can be downloaded remotely, by Internet for example, from a site specific.

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- la figure 7 représente schématiquement et partiellement, en perspective, une valise de rangement du détecteur de mouvement de la figure 2, - la figure 8 représente schématiquement et partiellement, en perspective, différents éléments constitutifs d'un détecteur de mouvement conforme à un deuxième exemple de mise en oeuvre de l'invention, équipant la raquette de la figure 1, - la figure 9 représente schématiquement et partiellement, en perspective, un assemblage de cartes électroniques du détecteur de la figure 8, - la figure 10 illustre différentes fonctions des détecteurs de mouvement des figures 2 et 8, - la figure 11 illustre schématiquement et partiellement un système d'aide à la pratique du tennis conforme à l'invention, - la figure 12 illustre schématiquement et partiellement différentes fonctions d'un programme permettant de visualiser et d'analyser des données obtenues à partir d'un détecteur de mouvement conforme à l'invention, - la figure 13 représente deux courbes illustrant les variations dans le temps d'une grandeur du mouvement mesurée par le détecteur du mouvement, et - la figure 14 illustre schématiquement et partiellement la connexion du système d'aide à la pratique du tennis de la figure 11 à un réseau d'ordinateurs. Other characteristics and advantages of the present invention will emerge on reading the detailed description which follows, of nonlimiting examples of implementation, and on examining the appended drawing, in which: - Figure 1 shows schematically and partially a tennis racket according to the invention, - Figure 2 shows schematically and partially, in perspective, different components of a motion detector according to a first example of implementation of the invention, equipping the racket Figure 1, - Figure 3 shows schematically and partially in section, a detail of an electronic card of the motion detector of Figure 2, - Figure 4 shows a schematic and partial section on IV-IV of connector of the detector of FIG. 2, FIGS. 5 and 6 schematically and partially represent two means of fixing the motion detector on the racket of t ennis,

- Figure 7 shows schematically and partially, in perspective, a storage case for the motion detector of Figure 2, - Figure 8 shows schematically and partially, in perspective, different components of a motion detector according to a second example of implementation of the invention, equipping the racket of FIG. 1, - FIG. 9 schematically and partially, in perspective, an assembly of electronic cards of the detector of FIG. 8, - FIG. 10 illustrates various functions of the motion detectors in FIGS. 2 and 8, - FIG. 11 schematically and partially illustrates a system for assisting the practice of tennis according to the invention, - FIG. 12 schematically and partially illustrates various functions of a program making it possible to view and analyze data obtained from a motion detector according to the invention, - Figure 13 shows presents two curves illustrating the variations over time of a magnitude of the movement measured by the motion detector, and - Figure 14 schematically and partially illustrates the connection of the system for assisting the practice of tennis in Figure 11 to a network computers.

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 FIG. 1 shows a tennis racket l, comprising a handle 3 and two branches 4 extending the latter and connecting to the sieve 2.

 This tennis racket 1 is equipped with a movement detector 5 removably fixed between the arms 4, on the side of the handle 3.

 As can be seen in FIG. 2, the motion detector 5 comprises two half-shells 6 and 7 made of plastic material, capable of being joined together to form a housing.

 The half-shells 6 and 7 each have a non-symmetrical shape of revolution so that their assembly on the racket can be carried out in a predetermined direction.

 The half-shell 6 supports an electronic card 10 on which are mounted three accelerometers 16a, 16b and 16c making it possible to measure components of the movement of the racket along the three orthogonal axes X, Y and Z represented in FIG. 1, the axis Y being parallel to the handle 3.

 The detector 5 is devoid of control buttons, or even also devoid of indicator lights, which makes it possible to have a relatively simple structure.

 Functions such as switching the detector 5 on or off are controlled remotely using radio frequency waves, thanks to the presence of a reception module 38, shown in FIG. 10.

 As can be seen in FIG. 3, the accelerometer 16a is fixed in a hole in the card 10 and extends along the thickness of the latter.

 The accelerometer 16a thus measures a component of the movement in the direction Z perpendicular to the plane of the electronic card 10.

 The accelerometer 16a is fixed to the card 10 by solder points 17a and 17b which also serve as electrical connections.

 The other two accelerometers 16b and 16c are fixed to the surface of the card 10 in two perpendicular directions, to measure the accelerations along the X and Y axes.

 Like the half-shell 6, the half-shell 7 supports an electronic card 18, visible in dotted lines in FIG. 2, provided with a transmitter making it possible to transmit signals representative of a magnitude of the movement obtained at starting from the components measured by the accelerometer 16a to 16c.

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 The detector comprises an internal connector ll, in the form of a tube, arranged to allow, on the one hand, the mechanical assembly of the two half-shells 6 and 7 and, on the other hand, to ensure the electrical connections between the two electronic cards 10 and 18.

 As shown in FIG. 4, the connector 11 comprises a first tubular element 20 integral with the half-shell 6 and having at its free end an annular bead 21 able to snap into elastically deformable tabs 22 belonging to the half -shell 7.

 After snap-fastening, the connector 11 is held in place by the tabs 22 against a second tubular element 23, belonging to the half-shell 7, and carrying electrical contacts.

 As a variant, the half-shells 6 and 7 may comprise means for fixing by screwing, of the quarter-turn type for example.

 The first tubular element 20 comprises in its thickness six conductors 13, four of which allow the transmission of data in digital form between the two electronic cards 10 and 18 and two allow the electrical supply of the latter when the elements 23 and 20 are combined.

 The elements 20 and 23 define a compartment 15 making it possible to receive a cell or battery 25, shown in dotted lines in FIG. 4, used for the electrical supply of the electronic cards 10 and 18.

 This cell or battery can be of * AA format.

 In the example described, a flexible strip 14 comprising fixing zones 14a, one with loops and the other with hooks, of the Velcro @ type, is fixed to the half-shell 6.

 The assembly of the two half-shells 6 and 7 is locked on the frame of the racket by surrounding them by means of the strip 14, the fixing zones 14a cooperating by hooking to securely hold the strip 14 around the half-shells 6 and 7.

 As a variant, grooves 29 can be produced on the half-shells 6 and 7 in extension of one another as shown in dotted lines in FIG. 2, these grooves 29 making it possible to accommodate an elastic bracelet, not shown, making it possible to lock the housing assembly.

 In another variant, as illustrated in FIG. 5, a detector 5 ′ of reduced dimensions can be fixed to the racket by means of a clip 30 comprising

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 loops 31 which can be closed on the branches 4.

 Another embodiment of the half-shells 6 and 7 is shown in FIG. 6, the half-shell 7 here comprising elastically deformable lugs 35 situated on the edge thereof.

 The tabs 35 of the half-shell 7 are arranged to engage by snap-fastening in recesses 36 of the other half-shell 6 during assembly.

 The recesses 36 are shaped so that, after assembly of the half-shells 6 and 7, a user can spread the tabs 35 with his nail in order to separate the half-shells 6 and 7.

 The detector 5 can be dismantled and stored in a suitcase 40, shown in FIG. 7, comprising a foam block 41 in which two housings 42 are arranged, each capable of receiving a half-shell 6 or 7.

 In the case where the detector 5 is powered by a battery, the storage case 40 can be equipped with a charger enabling this battery to be recharged.

 There is shown, with reference to FIGS. 8 and 9, a movement detector 80 according to another example of implementation of the invention, which can be fitted to the tennis racket 1.

 This motion detector 80 comprises two half-shells 81 and 82 made of plastic. The latter house an assembly 83 of three electronic cards 84, 85 and 86, the cards 84 and 86 being fixed on the card 85, perpendicular to the latter, as can be seen in FIG. 9. The card 84 supports on its face a set 87 of two accelerometers 87a and 87b making it possible to measure components of the movement of the racket along the axes X and Y represented in FIG. 1. The card 85 supports on its face an accelerometer 88 making it possible to measure the component of the following movement the Z axis.

 The card 86 is provided with a transmitter capable of transmitting signals obtained by means of the accelerometers 87a, 87b and 88.

 The assembly 83 is placed inside the half-shells 81 and 82 by means of balusters 90 which also make it possible to receive screws, not shown, for the assembly by screwing of the two half-shells 81 and 82 .

 The half-shell 82 which has an outer face 82a intended to rest against the branches 4, comprises a stud 91 capable of being joined to a block of foam 92,

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 by being introduced into an opening 93 thereof. The foam block 92 is shaped so as to be able to be housed between the branches 4, at the junction of the latter, and to be held there without significant play.

 The foam block may have deformation properties allowing it to be fixed on racket frames having different geometries.

 The motion detector 80 is held on the frame of the racket 1, at the branches 4, by means of a non-elastic band or bracelet 95 having hooking zones 95a of the Velcro type.

 The strip 95 has a length greater than the circumference of the handle 3, this length preferably being sufficient so that the strip 95 is suitable for several types of racket.

 At least one of the two attachment zones 95a can be sufficiently wide so as to be able to adjust the strip 95 to the geometry of the racket, one of the attachment zones, or even both, being able to extend over any the length of a loop of the strip 95.

 When a player accomplishes with the racket 1 a sequence of play, for example a series of services, backhand or forehand, the accelerometers 16a to 16c or 87a, 87b and 88 measure components of the movement characteristic of this sequence of play .

 The signals obtained by the accelerometers 16a to 16c or 87a, 87b and 88 are then shaped and amplified before being sent to an Analog / Digital converter 45, as illustrated in FIG. 10.

 The sampling frequency of the signals coming from the accelerometers 16a to 16c or 87a, 87b and 88 is chosen according to the desired precision.

 The sampling frequency of each accelerometer is thus at least 1000 Hz in the example described.

 The digital signals from the converter 45 are compressed and coded and then sent to the transmitter 37.

 The compression of the signals allows a high data rate and the coding of the signals makes it possible to avoid interference between several players using detectors 5 in the same zone.

 Within the antenna range of the transmitter 37 is placed a receiver 50, as illustrated

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 in figure 11.

 The range of the transmitter 37 is preferably between 10 and 100 m.

 This receiver 50 can be placed stationary in a corner of the tennis court, for example.

 Alternatively, the receiver can be incorporated into a watch worn by the player.

 In the example described, the receiver 50 allows, in addition to the reception of the signals transmitted by the motion detector 5 or 80, the storage of these signals in a memory 51, represented by dotted lines in FIG. 11.

 The transmission of the signals from the motion detector 5 or 80 to the receiver 50 is carried out in the example described in the band 433 MHz.

 Alternatively, a 2.4 MHz carrier can be used.

 In the example described, the receiver 50 is of relatively simple design, essentially having the function of receiving the signals emitted by the detector 5 or 80 and of storing them.

 As a variant, it is possible to equip the receiver 50 with a screen making it possible to display curves and / or tables obtained from the signals received.

 The receiver 50 advantageously comprises a transmission module 52 making it possible to send a radio signal to the reception module 38, this signal making it possible in particular to confirm the good reception by the receiver 50 of the signals transmitted by the transmitter 37 of the detector 5 or 80.

 This transmission module 52 can also be used to send instructions concerning the operation of the detector 5, in particular its start-up.

 The receiver 50 can be arranged to determine in real time whether a gesture made by the player is vitiated by an error or not, and in the event that an error is detected, emit an adequate sound or light signal, to warn the player.

 In the example described, the receiver 50 is connected to a computer 55 of the PC type capable of receiving and processing data stored in the memory 51.

 The data received by the computer 55 is processed and analyzed by an adapted program 60.

 FIG. 12 illustrates various functions of such a program 60.

 The latter comprises in the example described a menu 61 allowing

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l'utilisateur d'accéder à : un module 62 permettant l'identification de l'utilisateur, un module 63 permettant de commander la récupération des données depuis le récepteur 50 et le traitement de ces données. un module 64 permettant de commander l'affichage sur un écran 56 relié à l'ordinateur 55 des données obtenues grâce au module 63, un module 65 permettant l'analyse de ces données en comparant, par exemple, une courbe caractéristique d'une séquence de jeu avec une courbe de référence, et un module 66 permettant de réaliser des statistiques.

the user to access: a module 62 allowing the identification of the user, a module 63 making it possible to control the recovery of the data from the receiver 50 and the processing of this data. a module 64 making it possible to control the display on a screen 56 connected to the computer 55 of the data obtained thanks to the module 63, a module 65 allowing the analysis of this data by comparing, for example, a characteristic curve of a sequence of game with a reference curve, and a module 66 allowing to realize statistics.

 FIG. 13 shows two curves 70 and 71 representing the variations of a magnitude of the movement, for example the standard of the acceleration vector, the three components of which correspond to the three accelerations measured by the accelerometers 16a, 16b and 16c or 87a, 87b and 88, as a function of 1 / t, t representing time.

 Curve 70 is obtained by a player during a game sequence and curve 71 is used as a reference.

 This reference curve 71 can be obtained for example by the same player during a previous training session, and the comparison of the curves makes it possible to determine the progress of the player from one training session to another.

 The reference curve 71 can also correspond to a different player, a tennis professional for example.

 The comparison and the analysis of the signals are carried out by the program 60, which can for example recognize thanks to the shape of the curves, a determined gesture such as a forehand, a backhand or a serve.

 By storing the information acquired over several different training sessions, a player can track the progress made.

 The information acquired through the motion detector can also be used to define a general program for monitoring the player, both physically, technically and mentally.

 The program 60 can also be arranged to determine from the signals representative of the magnitude of the movement measured, the speed of the ball.

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 As illustrated in FIG. 14, the computer 55 is advantageously connected to a remote server 75 via the Internet network.

 Thus, a player can gather the information obtained during one or more training sessions on a PC and send it to the server 75, which allows for example a tennis professional to then analyze the information transmitted and do provide personalized advice to the player.

 Of course, the invention is not limited to the examples of implementation which have just been described.

 The signals transmitted by the motion detector can be processed so as to extract useful information therefrom before being sent to the receiver.

 The signals transmitted can be representative of a magnitude of movement other than acceleration, in particular speed.

 The player can wear a portable transceiver serving as a relay between the detector placed on the racket and the receiver placed on the field. Such a portable transceiver can be attached to the player's wrist, for example.

 The invention can also be used for the practice of other sports, sports articles such as a golf club, a squash racket, a baseball bat or a hockey stick which can be equipped with a detector. movement according to the invention.

Claims (19)

1. Sports article such as a tennis racket (1), characterized in that it comprises a movement detector (5; 80) comprising at least three static accelerometers (16a, 16b, 16c; 87a, 87b, 88) capable of measuring components of the movement of said article along three distinct axes (X, Y, Z) and by the fact that the detector comprises an emitter (37) capable of emitting signals representative of at least one magnitude of the movement, these signals being a function of the components thus measured.  2. Article according to the preceding claim, characterized in that said three axes (X, Y, Z) are orthogonal two by two.  3. Article according to the preceding claim, consisting of a tennis racket, characterized in that one of the three axes is parallel or coincident with the axis of the handle (3) of the racket.  4. Article according to any one of the preceding claims, characterized in that it comprises a housing preferably made of plastic.  5. Article according to the preceding claim, characterized in that the housing comprises two parts (6,7; 81,82), each in the general form of a half-shell, preferably being assembled in a removable manner.  6. Article according to the preceding claim, characterized in that one of the parts (6,7; 81,82) of the housing comprises a first fixing member and the other part a second fixing member, able to cooperate with the first fixing member during the assembly of the two parts, the first and second fixing members being in particular shaped to cooperate by screwing or snap-fastening.  7. Article according to any one of claims 4 to 6, characterized in that the housing is held on the article (1) by means of a bracelet (14; 95) surrounding the housing and comprising in particular means of Velcroo type closure (14a; 95a).  8. Article according to any one of claims 4 to 7, consisting of a tennis racket, characterized in that the housing is shaped to be fixed at the branches of the frame of the racket.  9. Article according to the preceding claim, characterized in that the housing comprises a stud (91) capable of engaging between the branches of the frame of the racket, this stud preferably being secured to a block of foam (92) suitable for accommodation <Desc / Clms Page number 16>  between said branches.  10. Article according to any one of claims 4 to 9, characterized by the housing accommodates at least two electronic cards, one of them (84) carrying two accelerometers (87a, 87b) and the other (85) carrying a third accelerometer (88), these two cards being arranged perpendicularly.  11. Article according to any one of the preceding claims, characterized in that the detector (5; 80) is arranged to compress and code the signals prior to their transmission.  12. Article according to any one of the preceding claims, characterized in that the motion detector (5; 80) comprises a reception module (38) making it possible to receive an acknowledgment of the good transmission of the signals transmitted by the transmitter (37), this reception module (38) possibly being able to receive instructions for controlling the operation of the detector (5), in particular for switching it on or off, and programming certain functions.  13. Article according to any one of the preceding claims, characterized in that it is constituted by a tennis racket (1).  14. Motion detector able to be mounted on a tennis racket (l) comprising a handle (3) connecting to a sieve (2) by two branches (4), characterized in that it comprises three accelerometers (16a , 16b, 16c; 87a, 87b, 88) making it possible to measure components of the movement of the racket along three distinct axes (X, Y, Z), the detector (5; 80) comprising an emitter (37) capable of emitting signals representative of at least one magnitude of the movement obtained from the measured components, the detector comprising a housing formed in particular by two parts (6, 7; 81.82) capable of being assembled, this housing being able to be fixed on the racket at the level of the two branches.  15. Aid system for practicing a sport such as tennis, characterized in that it comprises a movement detector (5; 80) mounted on a sporting article such as a tennis racket (1 ), comprising three accelerometers (16a, 16b, 16c; 87a, 87b, 88) making it possible to measure components of the movement of the article along three distinct axes (X, Y, Z), the detector further comprising a transmitter (37 ) capable of transmitting signals representative of a magnitude of the movement obtained from the components thus measured and by the fact that the system includes a receiver (50) capable of receiving <Desc / Clms Page number 17>  signals transmitted by the transmitter (37) and a storage space (51) for storing data relating to these signals.  16. System according to the preceding claim, characterized in that the receiver (50) is connected to a processing unit (55) such as a computer capable of supplying, from the signals received by the receiver, information, in particular in the form of curves and / or tables, allowing the analysis of game sequences accomplished by the player.  17. Diagnostic method for practicing a sport such as tennis, characterized in that it comprises the following stages: - performing at least one sequence of play with a sporting article such as a tennis racket, the latter comprising a motion detector comprising three accelerometers making it possible to measure components of the movement of the article along three different axes, transmitting to a receiver by means of a transmitter signals representative of at least one magnitude of the movement obtained from measured components, the receiver being arranged to receive and store said signals or transfer them to a storage space, - process said signals using a processing unit so as to establish a diagnosis on the sequence of play executed.  18. Method according to the preceding claim, characterized in that one memorizes different diagnoses of the same player corresponding to different training sessions in order to assess the progress made by the player of a training session on the 'other.  19. Method according to one of the two preceding claims, characterized in that one compares the diagnosis established for a player to that established for another player so as to assess the strengths and weaknesses of one compared to the other.