Device and method for measuring static aquatic activity

Abstract

A measurement system (10) for static aquatic activity performed by a user (1), comprising at least one measurement device (20) including at least one fastening element (22) configured to secure the measurement device (20) to a fixed anchor point (70), at least one load attachment (30) configured to be connected to the user and to receive tensile forces generated by the user (1) during the static aquatic activity, at least one strain sensor (80) configured to measure the tensile forces applied to the load attachment (30), and a calculator (40) configured to determine a true equivalence of aquatic performance based on the static aquatic activity profile and said at least one measurement of tensile forces. Abstract figure: Figure 1

Description

Title of the invention: Device and method for measuring static aquatic activity. Technical field

[0001] The present invention relates to the field of static aquatic activity measurement.

[0002] In the field of aquatic activities, there are devices used to measure and analyze performance achieved, notably using GPS, gyroscope and accelerometer type sensors; however, these devices remain limited to use in open water or in standard length swimming pools (25m or 50m).

[0003] In order to be able to carry out training sessions in small pools (less than 25m), there are swimming elastics and counter-current swimming devices designed to hinder the swimmer's progress, but these devices do not address the notion of measurement or that of analysis of the activity carried out.

[0004] In the prior art, patent application US2017 / 0157486A1 discloses a device for measuring the physical activity of a swimmer equipped with a stationary swim tether in a swimming pool. To obtain swimming data, it is necessary to input the height, weight, and stroke type to determine a conversion parameter, which is imprecise and does not take into account the concepts of glide and momentum. Such a measuring device provides imprecise swimming data, preventing a swimmer from changing strokes during a session.

[0005] French patent application FR3062313A1 discloses a device for measuring the physical activity of a swimmer equipped with a stationary swimming elastic in a swimming pool. The measuring device comprises a force sensor and a processing unit configured to provide at least one swimming information. This swimming information includes, in particular, the equivalent freestyle distance covered, an instantaneous speed, and the swimmer's instantaneous position. In practice, the information provided is unreliable and does not correspond to the actual distance that would be covered. During a swimming session, a swimmer performs different strokes successively to alternate periods of power and periods of rest. Each stroke does not have the same efficiency, which affects the relevance of the swimming information provided.Incidentally, patent application FR3062313A1 teaches how to estimate the frequency of acquired measurements in order to characterize the type of swimming practiced. However, the speed calculation does not take the type of swimming into account.

[0006] Such swimming data has very insufficient accuracy, which precludes any comparison or tracking between several consecutive sessions of a user. Furthermore, it prevents comparing the swimming data of several users. Distanced swimmers, each in their own pool, participate in a virtual race. Swimming data is particularly inaccurate for long swimming sessions where users change strokes multiple times.

[0007] The present invention is intended in particular to solve all or part of the aforementioned problems. PRESENTATION OF THE INVENTION

[0008] The invention proposes for this purpose a system for measuring static aquatic activity performed by a user, comprising: • At least one measuring device comprising: • At least one fastening element configured to secure the device to measurement at a fixed anchor point, • At least one load attachment configured to be connected to the user and to receive tensile forces generated by the user during the static aquatic activity, • At least one strain sensor configured to determine at least one measurement of tensile forces applied to the load attachment, • A connecting element configured to be worn by the user and / or by an aquatic device, and configured to be connected to the load attachment so as to transmit to the load attachment the tensile forces generated by the user during the performance of the static aquatic activity, the connecting element comprising a longitudinal body having a coefficient of elongation less than 20%, • A calculator configured for: • determine at least one static aquatic activity profile from said at least one measurement of traction efforts, • determine a real equivalence of aquatic performance, including speed, distance, frequency, power and / or energy, based on the static aquatic activity profile and at least one measurement of traction efforts.

[0009] Thus, thanks to the invention, when the user enters a pool equipped with the measurement system and begins their aquatic activity, a tension is applied to the load attachment and then to the strain sensor, which is analyzed by the computer. The computer can, for example, determine a real characteristic corresponding to the static aquatic activity, such as, for example, the practice of the crawl stroke associated with a speed and a distance. Thanks to the low elongation of the connecting element (related to its elasticity), precise tensile force measurements are available, resulting in greater accuracy in detecting the type of swimming and improved performance. Accuracy of the true equivalence of aquatic performance. A true equivalence of aquatic performance can be reliably determined even when the user performs several different swimming strokes consecutively. The true equivalence of aquatic performance is determined dynamically over time based on the aquatic activity. The true equivalence of performance is therefore highly relevant, reliable, and precise, allowing for comparison with another equivalence achieved at a different time or with those of other swimmers, particularly during a competition.

[0010] According to one aspect, the computer having access to at least one mathematical estimation model, the computer is configured to determine the static aquatic activity profile from said at least one measurement of traction forces and the mathematical estimation model.

[0011] According to one aspect, the calculator is configured to determine the static aquatic activity profile periodically, in particular, in real time, over a sliding window.

[0012] According to one aspect, the model for estimating the static aquatic activity profile is obtained by supervised learning.

[0013] According to one aspect, the longitudinal body has an elongation coefficient of less than 10%,

[0014] According to one aspect, the connecting member comprises at least one shock absorber connected to the body longitudinal. This reduces intermittent jolts to increase user comfort while maintaining high measurement accuracy.

[0015] The static activity measurement system according to the invention may comprise one or more of the following features, taken individually or in combination with each other: • the computer has access to a database associating a plurality of traction efforts with a plurality of static aquatic activity profiles, the computer being configured to compare said at least one measurement of traction efforts to the plurality of traction efforts in the database so as to determine at least one static aquatic activity profile; • said at least one static aquatic activity profile is chosen from surfing, canoeing, kayaking, stand-up paddleboarding, crawl, breaststroke, backstroke and butterfly, or another aquatic activity; • the calculator is configured to determine said actual equivalence of aquatic performance based on said static aquatic activity profile; • the calculator is configured to transmit said actual equivalence of aquatic performance; • The measuring device includes an audio (or audiovisual) output configured to transmit audio (or audiovisual) information. relating to the determined static aquatic activity profiles and / or the actual equivalence of aquatic performance; • the calculator belongs to the measuring device; • the calculator is connected to the measuring device via a data link (Bluetooth, Wifi); • the system comprising a linking element configured to be worn by the user and configured to be connected to the load attachment so as to transmit to the load attachment the tensile forces generated by the user during the performance of the static aquatic activity; • the connecting element having an elastic elongation coefficient, the calculator is configured to normalize the tensile force measurement over a predetermined time period as a function of the predetermined elastic elongation coefficient; • the calculator is configured to determine the elastic elongation coefficient of the connecting element; • the connecting element comprises a longitudinal body to transmit tensile forces and an audio (or audiovisual) transmission cable associated with said longitudinal body, one end of which is configured to be connected to the measuring device and the other end of which is configured to broadcast audio messages from the measuring device into an aquatic audio (or audiovisual) headset worn by the user;

[0016] The invention also relates to a method for measuring static aquatic activity performed by a user using a measurement system as described above, the user wearing the connecting member attached to the load-bearing attachment of the measuring device, the attachment member of the measuring device being connected to a fixed anchor point, the method comprising steps consisting of: • Determine at least one measure of the tensile forces applied to the load attachment over time by the user, • Determine at least one static aquatic activity profile from said at least one measurement of traction forces, • Determine a real equivalence of aquatic performance, including speed, distance, frequency, power and / or energy, based on the static aquatic activity profile and at least one measure of traction efforts.

[0017] The method according to the invention may also include one or more of the following steps: • compare said at least one measurement of traction forces to the plurality of traction forces in the database; • determine from this comparison at least one profile of static aquatic activity; • determine said actual equivalence of aquatic performance on the basis of said determined static aquatic activity profile; • to transmit said actual equivalence of aquatic performance. PRESENTATION OF THE FIGURES

[0018] The invention will be better understood and other details, features and advantages of the invention will become more apparent upon reading the following description, given by way of non-limiting example and with reference to the accompanying drawings in which:

[0019] Fig. 1 is a schematic general view of the static aquatic activity measurement system performed by an aquatic user;

[0020] [Fig.2] is a view similar to [Fig.1] showing a different aquatic user;

[0021] The [Fig.3] is a schematic representation of a fastening member and an external anchoring system of the measuring system;

[0022] Fig. 4 is a schematic view representing in particular a linking element of the measuring system;

[0023] Fig. 5 is a schematic view representing a leash of the connecting element;

[0024] Figure 6 is a schematic view of the electronic components of the device. measure ;

[0025] Fig. 7 represents a surface of the master frame, that is to say the orthogonal projection surface of the aquatic user on a vertical plane perpendicular to the axis of movement of said user;

[0026] The [Fig.8] is a graph representing curves of the forces captured by the measuring device during a user activity as well as its Fourier transform;

[0027] The [Fig.9] is a graph representing curves of the forces captured by the measuring device during a user activity, the corresponding calculated theoretical speed as well as the swimming detection;

[0028] Fig. 10 is a schematic representation of a linking element comprising at least one damper connected to the longitudinal body. DETAILED DESCRIPTION OF THE INVENTION

[0029] Figure 1 shows an overall view of the static aquatic activity measurement system 10 implemented by a user according to the invention. The measurement system 10 includes, in particular, a measuring device 20 comprising a fastening member 22 configured to secure the measuring device 20 to a fixed anchor point 70. The anchor point 70 is specifically configured to anchor itself in the vicinity of a Basin 2 is used for aquatic activities. The fixing element 22 is preferably inextensible. The measuring system 10 is thus immobilized in a fixed reference frame.

[0030] The measuring device 20 also includes a load attachment 30 configured to be connected to the user and to receive traction forces generated by the user during the performance of the static aquatic activity.

[0031] The measuring device 20 comprises at least one strain gauge 80 configured to measure at least one tensile force exerted by the user and applied to the load strap 30. By way of example, the load strap 30 is directly connected to the strain gauge 80. The measuring system 10 comprises, for example, a connecting element 50 configured to be worn by the user and / or by an aquatic device (e.g., a surfboard) and configured to be connected to the load strap 30 so as to transmit to the load strap 30 the tensile forces generated by the user 1 during the static aquatic activity. The connecting element 50 is thus connected to the strain gauge 80 via the load strap 30.

[0032] Furthermore, the measuring device 20 includes a calculator 40, connected to the strain sensor 80, capable of determining a real-world equivalent of aquatic performance, including speed, distance, frequency, acceleration, power, and / or energy, based on at least one measurement of traction forces, for example, over a predetermined period of time. This theoretical data represents data that the user would have achieved for the same effort in open water or in a 25m or 50m pool, without the connecting element 50. The calculator 40 is further configured to transmit the real-world equivalent of aquatic performance. The strain sensor 80 preferably generates a voltage, which is a function of the traction force, that can be read and interpreted by the calculator 40.

[0033] The calculator 40 can access a database 160 associating a plurality of traction force measurements with a plurality of static aquatic activity profiles and is specifically configured to compare said at least one traction force measurement with the traction force measurements in the database 160 in order to determine at least one static aquatic activity profile over the predetermined time period. The calculator thus makes it possible to determine the static aquatic activity profile (surfing, crawl, breaststroke, backstroke, butterfly, etc.).

[0034] The calculator 40 is configured to determine said actual equivalence of aquatic performance on the basis of said static aquatic activity profile, for example over a predetermined time period.

[0035] In other words, the calculator 40 collects the voltage signal and calculates a static aquatic activity profile, notably using data from database 160 or using a mathematical estimation model. It then deduces the measurements corresponding to the performances transposed into real aquatic activity based on these tensions.

[0036] In this document, by "static" we mean that the position of the aquatic user, taking the pool 2 as a reference point, does not change or hardly changes during the activity. In practice, there may be slight changes in this position, sideways or forwards and backwards, changes which we consider "static" within the scope of the present invention.

[0037] In this document, the term "static aquatic activity profile" refers to a category of physical activities that take place in water in a static manner. This category can include a wide range of aquatic activities that can be performed statically, such as front crawl, breaststroke, backstroke, butterfly, surfing, stand-up paddleboarding, canoeing, kayaking, and other aquatic activities. The static aquatic activity profile can be associated with elements of force, frequency, duration, and intensity of the exercise. Furthermore, breathing rates, arm stroke rates, and leg kick rates are important elements that can be associated with the static aquatic activity profile. For example, for swimming, the static aquatic activity profile can be associated with information on arm stroke rate, leg kick rate, breathing rate, and theoretical distance covered.Similarly, for surfing, the static aquatic activity profile can include information on paddling frequency, board volume, and theoretical distance covered. In short, the aquatic activity profile can be associated with a variety of elements, including force, arm and leg stroke frequency, and breathing rate.

[0038] According to the embodiment illustrated in [Fig. 1], the load attachment 30 comprises a metal loop 31 that can be welded or mechanically fixed to the strain gauge 80. The load attachment 30 is fixed in the measuring device 20, the measuring device 20 itself being retained by the fastening member 22 attached to the fixed anchor point 70, in particular so as to:

[0039] attach the aquatic user 1 to the fixed anchor point 70 so as to render their aquatic activity static; and

[0040] transmit the tension exerted by the aquatic user 1 to the strain sensor 80.

[0041] In [Fig. 1], the aquatic user 1 of the measuring device 20 is represented here as a swimmer 1. The static aquatic activity shown here is the crawl stroke. The aquatic user 1 is swimming forwards. He is held by the connecting member 50, which is itself attached to the load attachment 30, which is connected to the strain sensor 80, which is itself held by the fastening member 22. By swimming, the swimmer therefore exerts a force on the strain sensor 80 via the connecting member 50 and the load attachment 30.

[0042] The measuring device 20 is further configured to transmit to the aquatic user 1, in real time, information relating to his performance and calculated by the computer 40 via a transmission system 150. This transmission system 150 is represented here, for example, by an audio (or audiovisual) transmission cable 51 included in the connecting member 50. The audio transmission cable 51 connects at its user end to an audio (or audiovisual) transmission system 60, represented here by an aquatic headset 61.

[0043] The measuring system 10 can be used by a variety of aquatic user types. For example, as shown in [Fig. 2], the aquatic user could be a surfer 3. The surfer 3 paddles forward and is positioned on an aquatic device, for example, a surfboard 4. The connecting element 50 is carried by the aquatic device. Compared to the previous embodiment, the elements of the invention remain identical, but variations of the transmission system 150 and the audio transmission system 60 can be added to or substituted for those previously described. The transmission system 150 thus includes, for example, Bluetooth audio-video transmission 52. The audio transmission system 60 can, in this case, be more immersive in terms of audiovisual experience than an aquatic headset 61 and is, for example, a virtual reality headset or an augmented reality headset 62.

[0044] As illustrated in more detail in [Fig. 3], anchoring can be achieved by physically separating the fastening member 22 and the anchoring system 70. The purpose of the anchoring system 70 in this embodiment is to be configured as a fixed point to which the fastening member 22 of the measuring device 20 is connected. In this example, the anchoring system 70 is screwed to the ground (wooden deck, concrete, slab) near the basin, in particular by means of a base 75. The base 75 includes, for example, a plate 71 with holes drilled at its four corners 72 allowing screws 73 to be passed through, which will fix the measuring device 20 to the ground. In the center of the plate 71 there is in particular a ring segment 74. The fastening member 22 includes, for example, a fastening system 23 enabling it to connect to the ring segment 74 of the anchoring system 70.This fastening system 23 is here a carabiner with a rotation axis 24 allowing the fastening element 22 to easily clip onto the anchoring system 70.

[0045] The measuring device 20 includes, in particular, a non-slip and absorbent surface 21 which rests on the floor of the basin. This non-slip and absorbent surface 21 increases friction on the floor and protects the measuring device 20 and its components. The adhesive and absorbent surface 21 is intended to protect the measuring device 20 from vibrations and shocks during use.

[0046] In this embodiment, the fastening member 22 and the anchoring system 70 represent a physically separate anchoring but according to an alternative embodiment, they could be located in the same housing.

[0047] The anchoring system 70 can, for example, be implemented using a bar typically located on the starting blocks of swimming pools. The attachment to the bar is achieved, for instance, via at least one lockable, non-slip hook to prevent slipping along the bar. This solution allows for the simple use of the static aquatic activity measuring device 20 in a pool 2, particularly one open to the public.

[0048] The anchoring system 70 can in particular be made via a strap allowing attachment to any type of fixed support (barrier, block, ladder) or via a hook and loop system glued to the ground (wooden terrace, concrete, slab) or by planting a structure in the ground (earth, sand, rocks) near the basin 2.

[0049] In an embodiment (not shown) in which the anchoring system 70 can alternatively or complementarily be implemented as a counterweight to anchor the measuring device to the basin. The counterweight of the anchoring system consists of a box capable of containing various materials, such as water, sand, or other ballast materials, to create a fixed anchor point for securing the measuring device. This box can be filled with the appropriate ballast to obtain the weight necessary for the stability of the assembly. This counterweight solution is particularly advantageous because it can be adapted to all types of terrain. Indeed, the box can be filled with the ballast material available on site, which greatly facilitates the installation of the measuring device on different types of terrain.Furthermore, the flexibility offered by this solution also allows the counterweight weight to be adjusted according to the specific needs of each situation.

[0050] As shown in [Fig. 3], the measuring device 20 may include a secure compartment 25 for storing various items. This secure compartment 25 allows, in particular, the storage of the user's mobile phone 26 during the activity so that it can easily synchronize with the static aquatic activity measuring device 20 in cases where a connection between the two devices is required. The secure compartment is specifically waterproof.

[0051] The aquatic user's 1 connecting member 50 is particularly visible in [Fig. 4]. In this embodiment, the connecting member 50 includes a retention fastening system 54, here a carabiner. The retention fastening system 54 is attached to the load attachment 30, specifically at the mechanical loop 31, so as to secure the fastening member 22 and the connecting member 50 and to to allow the transmission of energy between the aquatic user 1 and the strain sensor 80 via the load attachment 30.

[0052] The connecting member 50 may also include a longitudinal body 53, which can be likened to a high-strength strap. The longitudinal body 53 has an adjustable length ranging from approximately 1.5 meters to 4.0 meters for standard use of the measuring system 10. For example, the length of the longitudinal body 53 can be adjusted using a conventional sliding and locking system 55, such as that generally used for adjusting the length of straps. This adjustment system allows the desired length of the longitudinal body 53 to be maintained reliably and securely.

[0053] The connecting member 50, and in particular its longitudinal body 53, has a coefficient of elastic elongation. The calculator 40 is configured, in particular, to normalize the tensile force measurement over a predetermined time period as a function of the coefficient of elastic elongation. The coefficient of elastic elongation of the connecting member 50 can be predetermined. Alternatively, the calculator 40 is configured to determine the coefficient of elastic elongation of the connecting member 50.

[0054] Such standardization improves the relevance of the traction force measurement and, consequently, the relevance of the actual aquatic performance equivalence. This allows for a reliable comparison of several actual aquatic performance equivalences from different users.

[0055] At the other end of the longitudinal body 53, the connecting member 50 includes a fastening element 58 for attaching the connecting member 50 to the aquatic user 1. The fastening element 58 is, for example, a fastening strap. Alternatively, the fastening element 58 allows the connecting member 50 to be attached to the aquatic user 1, for example, by means of a body restraint device 170 included in the connecting member 50 and worn by the aquatic user.

[0056] Preferably, the connecting member 50 comprises a longitudinal body 53 having an elongation coefficient of less than 20%. Even more preferably, the elongation coefficient is less than 10%. A low elongation coefficient advantageously allows for very precise measurement of forces during aquatic activity by increasing the sensitivity of the measurement. This is very advantageous in the present case since the aquatic activity can be obtained with high precision. Since the actual aquatic performance equivalent is determined from the aquatic activity (chained calculation), this directly impacts the accuracy of the actual aquatic performance equivalent.

[0057] According to one aspect of the invention, the connecting member 50 comprises at least one damper 59 connected to the longitudinal body 53. With reference to [Fig. 10], it is Figure 53 represents a longitudinal body with a low elongation coefficient, particularly in DYNEMA®, and a damper 59 in the form of an elastic band, having an elongation coefficient greater than 50%, connecting two longitudinal portions of the longitudinal body 53. The longitudinal body 53 forms a loop between the two longitudinal portions. In this example, the damper 59 has a rest length of between 2 and 10 cm.

[0058] Such a damper 59 allows the connecting member 50 to exhibit elastic behavior up to a tensile force threshold and rigid behavior beyond that threshold. Below the tensile force threshold, the forces are absorbed by the damper 59 because the loop is not under tension. Above the tensile force threshold, the forces are absorbed by the loop, which is under tension.

[0059] The connecting member 50 could be in various forms. For example, the longitudinal body could be hollow to define an internal cavity in which the shock absorber 59 is mounted.

[0060] Such a shock absorber 59 reduces intermittent jolts, for example, during start-up. User comfort is thus improved while maintaining a connecting element with a low elongation coefficient under nominal conditions for accurately measuring aquatic activity and the actual equivalent aquatic performance. The body restraint device 170, in one embodiment, comprises a belt 173 that can be floating and adjusts to the size of the aquatic user 1, and a fastening element 171 for attaching the body restraint device 170 to the connecting element 50 via the fastening element 58.

[0061] In one embodiment, the body restraint device 170 can be equipped with a floating section that conforms to the user's anatomy, particularly at the waist. The floating section is designed to improve the buoyancy of the aquatic user 1 by reducing its overall density at the waist, allowing them to float more easily on the surface of the water, thus regaining a position closer to that achieved during conventional swimming. The floating section can be made from buoyant materials such as polyethylene foam or other similar materials. It can be permanently attached or detached from the body restraint device 170 to allow for modular use. Furthermore, the floating section can be adjusted according to the size and shape of the aquatic user 1 for a more personalized fit.By using the body restraint device 170 equipped with the floating part according to this invention, the aquatic user 1 improves their buoyancy, which can increase their comfort and safety when using the static aquatic activity measurement system 10. The floating part also allows for a better distribution of the forces acting on the skin. aquatic user 1, which helps to avoid overheating and skin irritation.

[0062] Furthermore, the measuring device 20 may include a set of direct outputs 120. In this set of direct outputs 120, a female audio (or audiovisual) output 121 is configured to transmit audio (or audiovisual) information relating to the determined static aquatic activity profiles. The set of direct outputs 120 may include, in particular, one or more light-emitting diodes 122, a high-definition multimedia interface 123, a sound diffuser 124, and a display device, which may be a liquid crystal display 125.

[0063] In one embodiment, within the longitudinal body 53 of the connecting member 50, passes the audio transmission cable 51 terminating in a male audio (or audiovisual) plug 56. This same male audio plug 56 connects to the female audio output 121 of the direct output set 120 of the measuring device 20. At the other end of the longitudinal body 53, we find, for example, the audio transmission cable 51 terminating in an audio (or audiovisual) plug 57 intended to connect, in a specific embodiment, the aquatic audio headset 61.

[0064] In one embodiment, the audio (or audiovisual) feedback communicated via the aquatic headset 61 can transmit, for example: information relating to the activity performed (surfing, swimming, freestyle, backstroke, breaststroke, butterfly, etc.), information relating to the actual equivalent speed and the actual equivalent distance corresponding to the effort exerted, information relating to an actual equivalent position in a virtual race, and audible cues allowing the aquatic user 1 to have an understanding of their actual equivalent glide. This cue can be communicated, for example, by sending a sound at a constant actual equivalent distance traveled, for example, every actual equivalent meters covered, which will give the aquatic user 1 real-time information on their actual equivalent performance.

[0065] It should be noted that other modules can be used to provide "feedback" to the user of the measurement system of the invention. Examples include: the aquatic audio headset 61, the virtual reality or augmented reality headset 62, a smartphone or tablet, a smartwatch, connected swimming goggles, an outdoor speaker, and / or an aquatic sound probe submerged in the water of the pool 2.

[0066] Another embodiment is shown in [Fig. 5], in which the connecting member 50 can be attached to (or carried by) an aquatic device, in particular a floating one, such as a surfboard (paddleboard, canoe, kayak, etc.). The connecting member 50 comprises, for example, a leash 100 including an attachment system element 101 connecting to the fastening element 58. The The aquatic device (surfboard, paddleboard, canoe) has a cord attached to its rear. The leash 100 allows the connecting element 50 to be attached to this cord, for example, via a hook and loop fastener 102.

[0067] As can be seen in [Fig. 6], the calculator 40 may include in particular: • a load cell amplifier type component 42, configured to transform the voltage captured by the strain sensor 80 into a digital signal; • a processing unit 41 configured to collect the digital signal and calculate on this basis the real equivalence of aquatic performance, i.e. the real aquatic activity equivalence;

[0068] Calculator 40 may also include: • a storage memory 44 configured to locally store data from one or more aquatic user sessions 1.

[0069] It is possible to capture the voltage exerted by the user by attaching the strain sensor 80 to the load attachment 30. In one embodiment, the strain sensor 80 may be more specifically: a load cell. In this case, it may be powered by a rechargeable battery 46. In the embodiment of the invention, the battery 46 can be recharged via a universal charging port 45.

[0070] It should be noted that the measuring device and its calculator can be switched on via an on / off button 43. The electrical voltage produced by the load cell 80 is amplified using the load cell amplifier type electronic amplifier 42, enabling the provision of digital information to the processing unit 4L

[0071] In addition, a temperature sensor 90 measuring the temperature of the load cell 80 makes it possible to detect temperature variations and to make the information available to the computer 40.

[0072] In one embodiment, the calculation of measurements corresponding to actual aquatic activity is performed by the processing unit 41 of the computer 40, based on the captured force and temperature information. The processing unit 41 uses several algorithms to calculate precise measurements of aquatic activity in real time.

[0073] The storage memory 44 is also present in the invention. It is used by the computer 40 to store the data collected during static aquatic activity. This storage memory 44 allows the device to operate autonomously, without requiring a connection to a smartphone, tablet, computer, or external server. This feature offers great flexibility. of use for users, particularly in places where an Internet connection is limited or unavailable.

[0074] In summary, the presence of the processing unit 41 and the local storage memory 44 is an important aspect of the device enabling it to collect and process accurate data on aquatic activity in real time, autonomously and flexibly.

[0075] In another embodiment, the computer 40 can be connected to a more powerful external computer, such as a smartphone, tablet, computer, or server, via wireless communication such as Bluetooth or Wi-Fi. This connection reduces the computational load on the internal computer. In this embodiment, the processing unit 41 serves as a communication interface between the voltage sensor 80 and the external computer, ensuring data transmission via a Bluetooth or Wi-Fi connection.

[0076] In one embodiment, to enhance the security of data exposed by the computer 40 to an external computer or any other external receiver, several security measures can be implemented. For example, the data can be encrypted to prevent interception or alteration by a malicious third party. Furthermore, the data can also be signed to guarantee its authenticity and integrity, allowing the recipient to verify the origin of the data and ensure that it has not been modified during transmission. These additional security measures strengthen the protection of sensitive data and guarantee reliable and secure transmission.

[0077] As mentioned previously, the calculation performed by the computer 40 can be influenced by the temperature measured by the temperature sensor 90. During the use of the strain sensor 80, a large temperature variation (+ / - 5°C) can slightly alter the results obtained. In this situation, the computer 40 applies a correction based on the temperature difference detected throughout the operation in order to guarantee the accuracy of the results.

[0078] In order to obtain the true equivalence of aquatic performance, it is necessary to know the type of activity performed, because, for example, the forces exerted by a surfer 3 are different from those exerted by a swimmer 1. Similarly, at equal force, a swimmer 1 swimming freestyle will have a different speed than a swimmer 1 swimming breaststroke. It is therefore necessary that the calculator 40 be able to determine the static aquatic activity profile performed before it can define the true equivalence of aquatic performance.

[0079] According to a first aspect, the calculator 40 comprises a database 160 associating a plurality of tensile force measurements with a plurality of profiles of static aquatic activity. This data allows, in particular, the generation of so-called "neural network" algorithms used to: detect the type of aquatic activity or swimming style detect the elongation coefficient of the connecting element 50.

[0080] According to a second aspect, the calculator 40 has access to at least one mathematical estimation model. Preferably, the calculator 40 includes memory on which the mathematical estimation model is stored. The calculator 40 is configured to determine the static aquatic activity profile from said at least one measurement of traction effort and the mathematical estimation model. In practice, the mathematical estimation model makes it possible to dynamically detect the swimming stroke type in order to determine a swimming parameter for reliably and relevantly establishing the actual equivalence of aquatic performance. The mathematical estimation model is, for example, of the "neural network" type. Thus, if the user periodically changes their swimming stroke, a reliable and relevant actual equivalence of aquatic performance can be obtained over time. The accuracy of the measurement is significantly increased.

[0081] This is particularly advantageous when the actual equivalences of aquatic performance of several users need to be compared with each other in order to carry out a virtual race with each user in his own pool.

[0082] Preferably, the calculator 40 is configured to determine the static aquatic activity profile periodically, in particular, in real time, over a sliding window. This allows for optimal accuracy in the actual equivalence of aquatic performance over time.

[0083] Preferably, the mathematical model is obtained by supervised learning from many samples obtained for different static aquatic activity profiles.

[0084] According to one aspect, the mathematical model is also configured to detect the elongation coefficient of the connecting organ 50, in particular, by supervised learning. This makes the actual equivalence of aquatic performance over time even more precise and relevant.

[0085] In the example of a swimmer and as seen in [Fig.7], the swimmer 1 exerts a propulsion force Fprop 7 (here represented by an arrow against the direction of swimming) on ​​the connecting member 50 of the aquatic user 1. In this example, we consider that the connecting member 50 is completely static, that is to say that its coefficient of elongation is zero or close to zero.

[0086] In the figure, we can see a surface called the "master-frame surface" 5, which is defined as the projection of the swimmer's body onto a vertical plane 6 perpendicular to the axis of movement in the water. The master-frame surface is of a major importance in the efficiency of movement in water and will be used in the rest of the description.

[0087] According to the fundamental principle of dynamics, when a solid is in translation, the sum of the external forces to which it is subjected is equal to the product of its mass m and its acceleration a.

[0088] In our case, the forces exerted are:

[0089] the propulsion force Fprop

[0090] the drag force Fd

[0091] Fprop -Fd= ma

[0092] In turbulent regime, it is agreed that the drag force Fd is calculated as follows:

[0093] Fd = 0.5 p S Cd v 2 with S the surface area of ​​the master couple defined hereafter, P, the mass fluid volume (in kg / m³) and Cd the drag coefficient. We can therefore deduce that -Fprop -kv² - ma

[0094] Fpmp_kv2 =

[0095] dv _ Fprop-kv2 dt ~ m

[0096] dv _ of T Pp'0!' dt - mV + m

[0097] Let us state:

[0098] A=±

[0099] And:

[0100] G — m

[0101] The equation becomes:

[0102] Avi + B

[0103] Equation which we solve using Euler's method (with ôt representing a step size. The step size being the sampling period defined in calculator 40):

[0104] v^Vq+CM2

[0105] That is:

[0106] ( F?™? A 2) â / "l- r0 + \ m _»ïv0

[0107] It should be noted that the variable k depends on:

[0108] S, "master-couple surface" 5; defined as the projection of the swimmer's body onto a vertical plane perpendicular to the axis of movement 6. S depends on the frontal surface of swimmer 1, called a and expressed in m2, on the technical level of swimmer 1, called [3 (unitless), on his height called h (expressed in cm), on his mass called m (expressed in kg) and on the static aquatic activity profile, called y (unitless).

[0109] In order to determine k, we will denote a function f, such that:

[0110] k = f(a, P, y, m, h, p)

[0111] The theoretical instantaneous velocity v as a function of time t and known parameters is therefore: [01121 ((()=^-1)+(^-:^^^^

[0113] The theoretical average speed over a time interval is obtained by averaging the theoretical speeds over that same interval. From this theoretical average speed, we can deduce, for example, a theoretical distance traveled d during a time lapse t:

[0114] d=vt

[0115] The table below presents the results obtained by the calculator 40, in the context of using the static aquatic activity measurement system 10 in the following context:

[0116] a = 0.3m2 (corresponding to the frontal surface area of ​​swimmer 1)

[0117] ^=1.1 (coefficient corresponding to a very experienced swimmer 1)

[0118] y = 1.7 (coefficient corresponding to the crawl stroke)

[0119] p= 997 kg / m^cw corresponding to the density of water)

[0120] h = 182 cm (corresponding to the height of swimmer 1)

[0121] m - 78 kg (corresponding to the mass of swimmer 1)

[0122] [Tables 1] Fprop(t) in newton v(tl) in m / sv(t) in m / s 150 1.11 1.21 120 1.21 1.15 100 1.15 1.13

[0123] Figure 8 represents a possible visualization of calculated data 110 over a time lapse according to the algorithms of the calculator 40. The force curve 111 represents the evolution of the force Fx exerted in newtons on the load cell. In order to calculate the frequencies, we rely, for example, on the Fourier curve 112 representing the Fourier transform of the force curve 111. In the example in the figure, three frequency groups emerge: the frequency of arm strokes 113, the frequency of leg movements or foot strikes 114, and the frequency of head exit 115.

[0124] On the force curve 111, we can deduce the different phases of intensity, in this example we observe for example that swimmer 1 had a strong period of intensity 116 from t=5s to t=20s reaching 20 Newton at times and conversely, a weak period of intensity 117 from t=45s to t=65s.

[0125] Fig. 9 represents another possible visualization of calculated data 110 according to the algorithms of the computer 40. On this figure, we can observe the force curve 111 and its calculated equivalent in velocity expressed in m / s; this theoretical velocity curve 118 evolves over time according to the forces captured by the computer 40.

[0126] As explained previously, the calculator 40 is configured to determine the type of aquatic activity. This identification is carried out in particular using the shape of the force curve 111 and the shape of the Fourier curve 112. This pattern recognition is performed via an algorithm known as a "neural network". This algorithm is trained with a large and varied user base to enable it to have a very reliable recognition rate.

[0127] The two curves at the bottom of [Fig. 9] highlight the result obtained via the "neural network" algorithm. In this example, the detected aquatic activity is swimming, and in particular the front crawl (curve 119). This determination is performed periodically in order to dynamically update the parameter y, which determines the aquatic activity. Thus, the information provided is reliable when a swimmer performs several successive strokes during the same session, alternating periods of power and rest.

[0128] As explained previously, the computer 40 is also configured to detect the elongation coefficient of the connecting member 50. This detection is performed by exploiting the force curve 111. The higher the elongation coefficient, the smoother the force curve. A second "neural network" algorithm, also exploiting the force curve, allows the computer 40 to deduce the elongation coefficient of the connecting member 50.

[0129] The calculator 40 detects user errors in aquatic activity. This detection is achieved by using the force curve 111 and the Fourier curve 112. Specifically, by analyzing the regularity and frequency of arm strokes 113, the frequency of leg movements or foot kicks 114, and the frequency of head lift 115, the calculator 40 can detect errors such as: • a different propulsive force between the two arms • The foot strike frequency is insufficient or at the wrong rhythm • an irregular breathing rate

[0130] The calculator 40 also makes it possible to detect if the user is using the measuring device 20 abnormally. This type of detection makes it possible to detect attempts at cheating. This detection is carried out by exploiting the force curve 111 and the Fourier curve 112. Indeed, abnormal use (for example, a user who pulls on the linking organ 50 by hand) will not be able to reproduce oscillations and frequencies corresponding to what the algorithm is used to analyzing.

[0131] It is important to note that the calculator 40 can be connected to a database 160 via the internet, database 160 which can be used in the context of virtual competition between static aquatic users of the measurement system 10.

[0132] Thanks to the invention, a true equivalence of aquatic performance is reliably, rigorously, and precisely determined over time. This true equivalence of aquatic performance advantageously allows for the consideration of frequent changes in static aquatic activity, in particular, the type of swimming. Thus, during a session, a user obtains a true equivalence of aquatic performance that allows them to track their progress over time.

[0133] Advantageously, due to the accuracy achieved, the actual aquatic performance equivalencies of several users can be compared. This makes it possible to hold virtual races between users swimming in their own pools. A competition can thus be held between users with different aquatic activities.

Claims

1.

2. Demands A measurement system (10) for static aquatic activity performed by a user (1), comprising: • At least one measuring device (20) comprising: • At least one fastening element (22) configured to secure the measuring device (20) to a fixed anchor point (70), • At least one load attachment (30) configured to be connected to the user and to receive tensile forces generated by the user (1) during the performance of the static aquatic activity, • At least one strain sensor (80) configured to determine at least one measurement of tensile forces applied to the load attachment (30), • A connecting element (50) configured to be worn by the user and / or by an aquatic device, and configured to be connected to the load attachment (30) so as to transmit to the load attachment (30) the tensile forces generated by the user (1) during the performance of the static aquatic activity, the connecting element (50) comprising a longitudinal body (53) having a coefficient of elongation less than 20%, • A calculator (40) configured for: • determine at least one static aquatic activity profile from said at least one measurement of traction efforts, • determine a real equivalence of aquatic performance, including speed, distance, frequency, power and / or energy, based on the static aquatic activity profile and at least one measurement of traction efforts. Measurement system (10) according to claim 1, wherein the computer (40) having access to at least one mathematical estimation model, the computer (40) is configured to determine the static aquatic activity profile from said at least one measurement of traction forces and the mathematical estimation model.

3. Measurement system (10) according to any one of claims 1 to 2, wherein the computer (40) is configured to determine the static aquatic activity profile periodically, in particular, in real time, over a sliding window.

4. A measuring system (10) according to any one of claims 1 to 3, wherein the longitudinal body (53) has an elongation coefficient of less than 10%,

5. Measuring system (10) according to any one of claims 1 to 4, wherein the connecting member (50) includes at least one damper (59) connected to the longitudinal body (53).

6. Measurement system (10) according to any one of claims 1 to 5, wherein said at least one static aquatic activity profile is selected from surfing, crawl, breaststroke, backstroke and butterfly.

7. Measuring system (10) according to any one of claims 1 to 6, wherein the calculator (40) belongs to the measuring device (20).

8. Measurement system (10) according to any one of claims 1 to 7, the connecting member (50) having an elastic elongation coefficient, the calculator (40) is configured to normalize the tensile force measurement over a predetermined time period as a function of the predetermined elastic elongation coefficient.

9. Measurement system (10) according to any one of claims 1 to 8, wherein the calculator (40) is configured to determine the elastic elongation coefficient of the connecting member (50).

10. A method for measuring static aquatic activity performed by a user using a measuring system (10) according to any one of claims 1 to 9, the user wearing the connecting member (50) attached to the load attachment (30) of the measuring device (20), the fastening member (22) of the measuring device being attached to a fixed anchor point (70), the method comprising steps of: • Determining at least one measurement of tensile forces applied to the load attachment (30) over time by the user, • Determining at least one static aquatic activity profile from said at least one measurement of tensile forces, • Determining a true equivalence of aquatic performance, in particular, speed, distance, frequency, power and / or energy, depending on the static aquatic activity profile and said at least one measurement of traction efforts.