IT201800006950A1 - Kinematic detection and monitoring system of body movements in water, and related method - Google Patents

Description

DESCRIPTION

Technical field

The present invention refers to a kinematic detection and monitoring system of body movements in water, and to a related kinematic detection and monitoring method of body movements in water.

In general, the present invention finds application in the field of detecting and monitoring body movements or relative movements of body segments, also for training, sports, rehabilitation or diagnostic purposes.

Known art

In the context of thermal therapies, rehabilitation and sports applications cover a vast range of scenarios for motor exercises involving the body segments.

It is necessary to monitor the execution of these body movements, to ensure that they are carried out correctly from a rehabilitation point of view or that they are carried out effectively from a sporting point of view.

There are known solutions for detecting and kinematic monitoring of body movements, based on a plurality of sensors associated with the body or with segments thereof.

US2005 179202 (A1) refers to a system for tracking and evaluating movements in a multidimensional space that uses optical sensors. The solution known from US2005 179202 (A1) is ineffective for use in water, and also does not allow a detection with adequate precision for monitoring rehabilitation therapy.

The document US2012296235 (A1) refers to a system for monitoring physiotherapy exercises, including sensors of the "motion capture" type able to buy the movements detected with pre-recorded data and provide real-time feedback to the user and the professional sanitary. However, the known solution from US20 12296235 (A1) is ineffective for use in water, and also does not allow a detection having adequate precision for monitoring a rehabilitation therapy.

Document EP3067783 (A1) refers to a system and method of tracking human locomotion which provides for a relative measurement of body segments by means of electromagnetic sensory units, to trace the position of the user's feet. The solution known from EP3067783 (A1) is however unsuitable for use in water, and also does not allow adequate monitoring of movements during rehabilitation therapy.

Document US8593286 (B2) refers to a system and method for monitoring sports activities, in which sensors of the inertial type are associated with body segments of a user. However, the solution known from US8593286 (B2) is still unsuitable for use in water, and also does not allow adequate monitoring of movements during rehabilitation therapy.

Document US2015192413 (A1) refers to a method of tracking body movements by means of a set of sensors associated with body segments, which detect the 3D position and orientation of the segments. The solution known from US2 015192413 (A1) is however unsuitable for use in water, and also does not allow adequate monitoring of movements during rehabilitation therapy.

US8 165844 (B2) refers to a motion tracking system comprising a plurality of motion sensor modules positioned on various body segments, which capture the 3D position and orientation of the segments. The solution known from US8 165844 (B2) is however unsuitable for use in water, and also does not allow adequate monitoring of movements during rehabilitation therapy.

In general, the solutions presented above are unsuitable for the application of monitoring movements in water, which is instead required in many rehabilitation scenarios, including thermal ones, and for water sports.

The kinematic monitoring of body movements in the water presents a technical problem, due to the visual obstacle constituted by the phenomena of reflection and refraction in the water, which make it more difficult to monitor movements using visual detection techniques.

Therefore, operators (therapists or coaches) need solutions specifically configured for the detection and kinematic monitoring of body movements in the water.

Document US20 13237375 (A1) refers to a training apparatus in a swimming pool, for controlling the position of a user of a pool, and providing luminous visual alarms relating to the position of the swimmer according to predetermined criteria. However, the solution known from US20 13237375 (A1) only monitors the position of the swimmer with respect to the edges of the pool, making this solution not effective for monitoring movements during a rehabilitation therapy.

Document WO20 15 155069 (A1) refers to a wearable device for monitoring the performance of a swimmer in the water; this device comprises heart rate sensors and inertial motion sensors to detect the position of the swimmer in space. However, the device known from WO20 15155069 (A1) detects kinematic parameters which are measured only at the swimmer's back, making it ineffective for monitoring movements during rehabilitation therapy.

Document US7980998 (B2) refers to a detection device comprising a single sensor unit, of the inertial type, for monitoring the movements of swimmers, and also refers to a communication system with which an instructor communicates with a plurality of swimmers. giving information on training. However, the device known from US7980998 (B2) detects kinematic parameters, such as absolute position and orientation, which are measured individually for each body part of the swimmer, making this device not effective for monitoring movements during rehabilitation therapy.

The solutions of the known art generally have the disadvantage of not allowing an effective detection of body movements during a rehabilitation therapy or a sports exercise in water.

In addition, known art solutions generally have the disadvantage of not providing effective monitoring, which constitutes a valid aid for carrying out rehabilitation therapy or sports activities.

Summary of the invention

An object of the present invention is to obviate the drawbacks of the known art.

A particular object of the present invention is to present a kinematic detection and monitoring of body movements, performed in a multisegment and which are accurate and reliable.

A further particular object of the present invention is to present a kinematic detection and monitoring of body movements which allow a quantitative supervision of motor gestures, in particular for rehabilitation or sports purposes.

A further particular object of the present invention is to present a kinematic detection and monitoring of body movements performed in water.

A further particular purpose of the present invention is to present a kinematic detection and monitoring of body movements that allow to deliver immediate feedback in real time, for any correction or modification of the motor gesture in progress.

A further particular object of the present invention is to present a kinematic detection and monitoring of body movements by means of an optimized processing of the measured data.

A further particular object of the present invention is to present a kinematic detection and monitoring of body movements which are more functional for therapeutic and rehabilitative applications in water.

These and other purposes are achieved by a kinematic detection and monitoring system of body movements in water and by a kinematic detection and monitoring method of body movements in water, according to the characteristics of the attached claims which form an integral part of the present description.

An idea underlying the present invention is to provide a kinematic detection and monitoring system of body movements in water, comprising: a wearable device for a user and suitable for use in water, comprising at least two inertial measurement units (IMU) respectively suitable to be associated with at least two body segments of said user, said body segments defining between them at least one variable angle with a body movement, said at least two inertial measurement units comprising sensors configured to detect kinematic quantities of said body movement and convert them into measured data , and further comprising at least one master node connected to said at least two inertial measurement units to collect said measured data, said master node being further configured for an online transmission of said measured data.

The kinematic detection and monitoring system further comprises a processing system comprising: a receiver configured for online reception of said measured data, and further comprising a computer operatively connected to said receiver and configured to reconstruct said body movement of said user in real time starting from said measured data, and further configured to perform a comparison between said reconstructed body movement and predefined kinematic parameters.

The kinematic detection and monitoring system further comprises a feedback system comprising: at least one feedback device configured to receive information relating to said comparison and further configured to deliver at least one indication on said body movement at least to said user based on said information .

Advantageously, the system of the present invention allows to detect and monitor multisegment body movements in an accurate and reliable way.

Furthermore, advantageously, the system of the present invention allows quantitative supervision of the movement also by the user, or by the executor of the movement, with particular advantages in therapeutic, rehabilitative or sports areas.

In particular, advantageously, the system of the present invention allows the monitoring of the goodness of body movement both by the user and, optionally, by an operator (therapist or coach),

Furthermore, advantageously, the system of the present invention allows immediate and real-time feedback to be delivered to the user, for any correction or modification of the motor gesture in progress.

Advantageously, the system of the present invention is particularly suitable for detecting and kinematic monitoring of body movements performed in water.

Advantageously, the system of the present invention allows an optimized processing of the measured data for the reconstruction of body movement.

According to a further aspect, an idea underlying the present invention is to provide a method of kinematic detection and monitoring of body movements in water, in which a user wears and uses a wearable device in the water, comprising: respectively associating at least two units of inertial measurement of at least two body segments of said user, said body segments defining between them at least one variable angle with a body movement, and by means of sensors detecting kinematic quantities of said body movement and converting them into measured data; collect said measured data, transmit and receive them Online; calculating and reconstructing said body movement of said user in real time starting from said measured data, and performing a comparison between said reconstructed body movement and predefined kinematic parameters; deliver, based on said comparison, at least one indication on said body movement at least to said user.

Further characteristics and advantages will become more evident from the detailed description given below of preferred, non-limiting embodiments of the present invention, and from the dependent claims which describe preferred and particularly advantageous embodiments of the invention.

Brief description of the drawings

The invention is illustrated with reference to the following figures, provided by way of non-limiting example, in which:

Figures 1a and 1b illustrate an embodiment of a wearable device for a kinematic detection and monitoring system according to the present invention.

Figure 2 schematically illustrates an embodiment of a kinematic detection and monitoring system according to the present invention.

Figures 3a, 3b, 3c, 3d, 3e, 3f illustrate examples of screens provided by a visual feedback system in a kinematic detection and monitoring system according to the present invention.

In the different figures, similar elements will be identified by similar reference numbers.

Detailed description

Figures la and 1b illustrate, in respective front and rear views, an embodiment of a wearable device 100 for a kinematic detection and monitoring system according to the present invention.

The wearable device 100 is suitable for a user and is suitable for use in water, preferably both fresh and salt water, even in a thermal context. The wearable device 100 supports sensors, which will be further described, for detecting bodily movements even in water. The wearable device 100, in general, is easy to wear, does not represent an obstacle to the execution of movements and is adjustable in width and length to adapt to the user's build.

The wearable device includes 101 inertial measurement units, also referred to as IMU [Inertial Measurement Unit).

These inertial measurement units 101 are respectively suitable to be associated with the user's body segments, where the body segments define at least one variable angle between them with a body movement. In the preferred embodiment, the inertial measurement units 101 are associated with: forearm, arm, femur, tibia, upper trunk and lower trunk of the user.

In particular, preferably, the wearable device 100 comprises two parts 100a and 100b which can also be worn independently: an upper part 100a for detecting movements of the upper trunk and upper limbs, and a lower part 100b for detecting trunk movements. lower and lower limbs.

In the preferred embodiment, each of the two parts 100a or 100b of the wearable device 100 comprises five inertial measurement units for monitoring the limbs bilaterally. Even just three inertial units of measurement could be used to monitor a limb unilaterally. It is understood that to monitor a generic movement of a limb, at least two inertial measurement units associated with at least two respective body segments capable of defining a variable angle with one movement would be sufficient.

In general, among these at least five inertial measurement units 101 of the parts 100a or 100b, two are respectively associated with distal portions of limbs (forearm or tibia), a further two are respectively associated with proximal portions of limbs (humerus or femur), and one is respectively associable to a trunk portion (upper or lower) of the user.

In general, the inertial measurement units 101 comprise sensors configured to detect kinematic quantities of a body movement and to convert them into measured data. In particular, such sensors include accelerometers, gyroscopes and geomagnetic sensors. In a preferred embodiment, each inertial measurement unit 101 comprises a triaxial accelerometer, a triaxial gyroscope, a triaxial geomagnetic sensor and a microcontroller responsible for interpreting and converting the detected kinematic quantities into measured digital data.

The wearable device 100 further comprises at least one master node 102, connected to the inertial measurement units 101 to collect the measured data.

Preferably, the master node 102 is connected to the inertial measurement units 101 by means of wired connections, in particular with connectors of the waterproof type. In general, the inertial measurement units 101 and the master node 102 include waterproof casings.

In one example, the inertial measurement units 101 form a sensor network managed at the level of the master node 102. Each sensor node 101 collects data independently, but is connected via a connector (preferably with IP68 protection) to the master node 102. The master node 102 is able to read data from all sensor nodes 101 by means of an appropriate communication protocol.

In the preferred embodiment, the master node 102 comprises an electric battery for powering the inertial measurement units 101 connected to it.

The master node 102 is further configured for an online transmission of the measured data. Preferably the master node 102 comprises an online wireless transmitter, in particular at a frequency of 20 Hz, preferably using a 0.9 GHz Wi-Fi or MiWi communication protocol.

Preferably, the master node 102 is at least partially positioned, in the wearable device 100, in a raised position when used in water, to improve data transmission.

Advantageously, the wearable device 100 does not require a positioning of the inertial measurement units 101 in precise coordinates on the various body segments of the user, thanks to a special calibration procedure which will be further described.

Figure 2 schematically illustrates an embodiment of a kinematic detection and monitoring system 200 according to the present invention.

The kinematic detection and monitoring system 200 comprises the wearable device 100 already described; for example, the user wearing the wearable device 100 is immersed in a tub or swimming pool 2.

The kinematic detection and monitoring system 200 then comprises a processing system 201. The processing system 201 comprises a receiver 202 which is configured for online reception of the measured data from the master node 102, as already described.

In the present description, the term "online" is intended to mean "which occurs substantially in real time", or which allows - in a way that is clear to the skilled in the art - instant-by-instant detection and monitoring, simultaneously with the execution of the movement, except for a slight delay due to data transmission and processing.

The processing system 201 further comprises a computer 203 operatively connected to the receiver 202 and configured to reconstruct the user's body movement in real time, from the measured data. Further, the computer 203 is configured to perform a comparison between the reconstructed body movement and predefined kinematic parameters, or "target" parameters for the movement requested by the user.

The computer 203 is configured to reconstruct the body movement in real time, by calculating at least one relative angle measured between at least two inertial measurement units 101.

In general, the processing system 201 is able to reconstruct the user's body movement in real time, cooperating with the measurements detected by the wearable device 100, as exemplified below.

Each of the inertial measurement units 101 measures its angular displacement with respect to a fixed reference system, identified by the direction of acceleration due to gravity and the magnetic North Pole.

To estimate the angles of the joints, it is necessary to measure the orientation of two adjacent body segments. In this work, the joint angles of the upper limbs and the lower limbs are alternately measured, and in particular, for the chest of the upper limb, the angles of the shoulder and elbow are estimated, both for the lower limbs and for the angles of the upper limb. hip and knee. The implicit assumptions of the presented approach are: i) the joints are modeled as ball joints; ii) each sensor is fixed relative to its body segment (i.e., relative motion due to muscle or tissue motion is neglected); iii) limbs and back are modeled as rigid segments.

Three sensors are preferably used to monitor three respective nodes: - a reference node which is preferably placed on the back (when monitoring the upper limbs) or on the pelvis (when monitoring the lower limbs); - an upper knot that is placed on the arm (when monitoring the upper limbs) or on the thigh (when monitoring the lower limbs); - a lower knot, positioned on the forearm (when monitoring the upper limbs) or on the tibia (when monitoring the lower limbs).

The sensors must be positioned on the corresponding segment, but advantageously it is not necessary for the exact positioning to be repeatable between sessions.

The angles of the body segments are preferably calculated according to the conventions provided by the International Society of Biomechanics (ISB).

Preferably, the processing system 201 is configured to perform a static calibration step and a subsequent dynamic calibration step to reconstruct the user's body movement.

In the static calibration step, a calibration is performed in which the at least two inertial measurement units are in a condition in which the respective at least two body segments are aligned along the same axis.

In the dynamic calibration step, a subsequent calibration is performed by detecting an angle variation, preferably of an angle of less than 20 degrees, between the at least two inertial measurement units with a body movement in the sagittal plane of said user.

Advantageously, both the static calibration step and the dynamic calibration step can be performed before the user is immersed in the tub or pool 2, thus being able to visually check the quality of the movement performed by the user during the dynamic calibration step.

The kinematic detection and monitoring system 200 then comprises a feedback system. The feedback system comprises at least one feedback device 204, configured to receive information relating to the comparison between the reconstructed movement and the predefined kinematic parameters.

Furthermore, the feedback system is configured to deliver, based on the aforementioned information, at least one indication on body movement, in which this indication is provided at least to the user in the tub or pool, who is able to exploit the signaling of the device feedback 204.

Preferably, the predefined kinematic parameters include amplitude and / or speed of execution of a movement, to deliver real-time feedback to the user on the goodness of execution of a given movement.

The feedback device 204 preferably comprises a display or a headset or a tactile element in the wearable device 100, so as to provide the user with a visual or acoustic or tactile indication (for example, vibrating) to increase awareness of one's own body position and movements that the user performs.

The indication on the goodness of execution of a given movement is in particular configured for the control of the amplitude and / or speed of execution of the body movement by the user.

Preferably, the feedback system comprises at least a second feedback device 205 for an operator 3, preferably a display associated with the computer 203. This second feedback device 205 is adapted to deliver second information relating to the reconstructed body movement and the comparison made. In this way, the second feedback device 205 is configured to deliver, based on the second information, also to the operator 3 at least one indication on body movement. In particular, operator 3 is a coach or a therapist who monitors the user's session in the tub or pool 2.

Advantageously, the second feedback device 205 can deliver an alarm signal if the wearable device 100 detects a fall of the trunk with respect to the gravitational axis, potentially indicative of a loss of balance and a risk of the user drowning in the tank 2.

In general, the kinematic detection and monitoring method according to the present invention can be implemented in the kinematic detection and monitoring system 200 of body movements in water according to the present invention. The characteristics of the latter are therefore also to be referred to the method, as described here.

Figures 3a, 3b, 3c, 3d, 3e, 3f illustrate examples of screens provided by the feedback device 204 or 205 in the event of a visual feedback. The user interface is referred to below as "biofeedback" interface.

The feedback device 204 can also be interfaced with users under medical care or the elderly, providing an output that is as simple and understandable as possible while maintaining a sufficient level of information content. During water therapy, the user is typically unable to use goggles; the essential visual outputs have been selected to be properly legible.

As visible in Figure 3a, the user interface preferably comprises two stylized human figures 301 and 302 representing the starting and ending positions of the movement, and a cursor 303 connected to the joint selected to be representative of the exercise, for example elevation of the shoulder in a range 304.

As shown in Figure 3b, visual feedback is provided to the user based on his position: different background colors 306 warn the user when he approaches the objectives. In the upper right corner, the number 305 of repetitions performed on the total required is indicated.

As seen in Figure 3c, an additional angle of motion can be monitored, linked to the biofeedback resulting in an alert 307, for example a red exclamation point, whenever a corresponding threshold is exceeded. For example, during shoulder exercises, the elbow must remain extended. In this case, the elbow angle can be selected as a monitored secondary angle. In the example, when the user flexes his elbow beyond a threshold defined by the operator, the red exclamation mark 307 appears, reminding the user to keep the elbow extended.

Three biofeedback modalities have been designed and in particular:

"Amplitude control biofeedback": the user is led to perform an angular excursion previously defined by the operator at a self-stimulation speed. The user can interrupt at any time.

"Amplitude / speed control biofeedback": the user is required to perform an angular excursion previously defined by the operator at a defined speed. Negative feedback (such as the turtle 308 in Figure 3d) is provided when the movement speed is slower than required.

"Bio feedback Tutor": the user is required to perform an angular excursion previously defined by the operator at a defined speed following a virtual tutor. In the training progress bar, next to the cursor connected to the joint angle chosen to represent the exercise (e.g. Shoulder elevation for shoulder abduction / adduction exercises), a second cursor 309 is shown as shown in Figure 3e, which represents the desired articulation position). A green-yellow-red color code is preferably adopted for the angular excursion bar so that the bar alerts the user when the absolute distance between the two pointers increases. After performing a complete movement, the user is asked to wait in the rest position by a countdown before proceeding with the new repetition.

As shown in Figure 3f, a dedicated biofeedback mode is provided during full-body movements, called "Rhythm Monitoring Biofeedback": the user interface consists of a foot silhouette representing the position of the starting movement and an indicator of “step”, which shows the performance (average values of the last 5 repetitions, indicated as [step / minute]) of the current session.

The feedback system shows selected parameters optimized for the user's needs, in order to provide the user with online feedback about the correctness of execution of the rehabilitation exercise or movement in general.

Through the operator monitoring interface, preferably displayed on the feedback device 205, the operator is given the opportunity to customize the exercise for the current user and decide which angles to monitor in real time. It is therefore possible to select and customize which parameters are shown by the feedback system, by acting on an interface available to the operator (therapist or coach).

At the end of each training session, the user's performance is evaluated with a score, for example on a scale from 0 to 100, making it possible to quickly compare the sessions over time, keeping the user monitored and motivated

Preferably, the computer 203 is operationally connected to at least one memory and configured to store the measured data for subsequent processing. In this way, the operator (therapist / coach) can access detailed reports of the rehabilitation or body movement session, with a complete description of the kinematics of all the movements of the various body segments monitored, to evaluate the user's performance.

Industrial applicability

The applications of the presented system potentially range from rehabilitation to athletic training to research in the field of aquatic kinematics.

Since biofeedback allows a faster and more effective recovery, the system of the present invention can be applied in the therapy of orthopedic and rheumatic diseases accompanied by general symptoms: subacute and chronic pain syndromes, ROM reduction, post-injury recovery of soft tissue o bone and postoperative recovery; correction of scoliosis and pain management, especially for back pain; sports trauma and spinal trauma.

The system of the present invention can also be applied to neurological diseases: where both biofeedback and the condition of microgravity of immersion in water (which allows movement even in the presence of significant motor unit recruitment deficits) find precise indications.

The aquatic movements guided by biofeedback advantageously allow the stimulation of the residual cognitive functions of patients.

Thanks to the movement analysis functions, the system according to the present invention could be used in prevention, allowing the physician to anticipate the detection of changes in the pathological conditions.

Considering the description given here, the person skilled in the art will be able to devise further modifications and variations, in order to satisfy contingent and specific needs. The embodiments described here are therefore to be understood as illustrative and non-limiting examples of the invention.

Claims (15)

CLAIMS 1. Kinematic detection and monitoring system for body movements in water, comprising: a wearable device (100) for a user and suitable for use in water, including: at least two inertial measurement units (101) respectively adapted to be associated with at least two body segments of said user, said body segments defining between them at least one variable angle with a body movement, said at least two inertial measurement units (101) comprising sensors configured to detect kinematic quantities of said body movement and convert them into measured data, - and further comprising at least one master node (102) connected to said at least two inertial measurement units (101) to collect said measured data, said master node (102) being further configured for an online transmission of said measured data; a processing system (201) comprising: - a receiver (202) configured for online reception of said measured data, - and further comprising a computer (203) operatively connected to said receiver (202) and configured to reconstruct said body movement of said user in real time starting from said measured data, and further configured to perform a comparison between said reconstructed body movement and predefined kinematic parameters; a feedback system including: - at least one feedback device (204) configured to receive information relating to said comparison and further configured to deliver at least one indication on said body movement at least to said user based on said information. 2. System according to claim 1, in which said at least two inertial measurement units (101) and said at least one master node (102) comprise watertight casings. System according to claim 2, wherein said master node (102) is connected to said at least two inertial measurement units (101) by means of at least one wired connection, in particular a wired connection with waterproof connectors, said master node ( 102) being at least partially positioned, in said wearable device, in an emerged position during said use in water. System according to claim 3, wherein said master node (102) comprises an online wireless transmitter, preferably using a Wi-Fi or MiWi communication protocol. System according to any one of claims 1 to 4, wherein said sensors configured to detect kinematic quantities include accelerometers, gyroscopes and geomagnetic sensors. System according to any one of claims 1 to 5, wherein said wearable device (100) comprises at least five inertial measurement units (101), of which two (101) are respectively associable with distal limb portions, a further two ( 101) are respectively associable to proximal limb portions, and one (101) is respectively associable to a trunk portion of said user. System according to any one of claims 1 to 6, wherein said computer (203) is configured to reconstruct said body movement in real time by calculating at least one relative angle between said at least two inertial measurement units. System according to claim 7, wherein said processing system (201) is configured to perform a static calibration step and a subsequent dynamic calibration step to reconstruct said body movement of said user, wherein said static calibration step is configured by means of said at least two inertial measurement units (100) being said at least two body segments aligned along the same axis, and in which said dynamic calibration step is configured by detecting an angle variation, preferably of an angle of less than 20 degrees, between said at least two inertial measurement units (100) with a body movement in the sagittal plane of said user. System according to any one of claims 1 to 8, wherein said predefined kinematic parameters include amplitude and / or speed of execution. System according to any one of claims 1 to 9, wherein said feedback device (204) comprises a display or a headset or a tactile element of said wearable device, and wherein said at least one indication provided to said user it is visual or acoustic or tactile. 11. System according to claim 10, wherein said at least one indication is configured for the control of the amplitude and / or speed of execution of said body movement of said user. System according to any one of claims 10 or 11, wherein said feedback system comprises at least a second feedback device (205) for an operator, preferably a display, adapted to deliver second information relating to said reconstructed body movement and to said comparison, and further configured to deliver, on the basis of said second information, at least one indication on said body movement to said operator. 13. A method of kinematic detection and monitoring of bodily movements in water, where a user wears and uses a wearable device (100) in the water, comprising: - respectively associating at least two inertial measurement units (101) to at least two body segments of said user, said body segments defining at least one variable angle with each other with a body movement, and by means of sensors detecting kinematic quantities of said body movement and converting them into data measured; - collect said measured data, transmit and receive them Online; - calculating and reconstructing said body movement of said user in real time starting from said measured data, and performing a comparison between said reconstructed body movement and predefined kinematic parameters; - deliver, on the basis of said comparison, at least one indication on said body movement at least to said user. Method according to claim 13, in which at least one relative angle is calculated between said at least two inertial measurement units (101) and said body movement of said user is reconstructed, and further comprising: perform a static calibration step in which said at least two inertial measurement units (101) are on said at least two body segments aligned along the same axis, carrying out a subsequent dynamic calibration step, detecting an angle variation, preferably of an angle of less than 20 degrees, between said at least two inertial measurement units (101) with a body movement in the sagittal plane of said user. Method according to claim 13 or 14, which can be implemented in a kinematic detection and monitoring system (100) of body movements in water according to any one of claims 1 to 12.