System and method for positioning sensor patch on user

Abstract

There is provided a system (10) for positioning a sensor patch on a user, the system comprising: a strip (20) for generating a pressing force on the sensor patch when the strip is stretched, the strip comprising a stretchable portion (22) and a first marker (25) located on the stretchable portion; and a non-stretchable element (30) having a second marker (35), where the non-stretchable element (30) is a strip mounted on the strip (20), the strip having a connector (55) or an elastic joint (51b) at one end and an elastic joint (51, 51a) at the other end, the strip allowing stretching of the strip even when tensioned, and where the non-stretchable element (30) is a non-stretchable element (30) having a second marker (35), where the non-stretchable element (30) is a strip mounted on the strip (20), where the non-stretchable element (30) is a strip mounted on the strip (20), where the strip has a connector (55) or an elastic joint (51b) at one end and an elastic joint (51, 51a) at the other end. The relative position of the first marker and the second marker indicates the stretching amount of the stretchable part. A user guided by the relative position of the first marker (25) and the second marker (35) may take action on the stretchable portion (22) of the strip to achieve a desired stretch corresponding to a desired pressing force on the sensor patch. A corresponding method (100) for positioning a sensor patch on a user is also provided.

Description

Technical Field

[0001] The present invention relates to systems and methods for positioning a sensor patch on a user. More specifically, the present invention relates to a system including a strip that at least allows monitoring of the tension applied by the strip to the user. Background Art

[0002] US2003144596A1 relates to a strip structure adapted to be used with a bioinformation sensing device for sensing bioinformation such as arterial pulse, etc., and to a bioinformation sensing device using the strip structure, or more specifically, to a bioinformation sensing device of the type such as an arterial pulse wave detector wound around a wrist, etc.

[0003] US2013104288A1 generally relates to medical devices, and more specifically to medical sensors for sensing physiological parameters of a patient.

[0004] Sensor patches including electrodes can be used for electrophysiological measurements, which involve the measurement of voltage changes or currents in biological tissues. These measurements can be used to monitor biometric parameters of an object or for diagnostic purposes, e.g., based on electrocardiogram (ECG) or electroencephalogram (EEG). Another example is pregnancy monitoring based on electrical-cardiotocography (eCTG), e.g., determining fetal heart rate (FHR), maternal heart rate (MHR), and uterine activity (UA). The sensor patch can include wet electrodes, dry electrodes, or semi-dry electrodes. For sensor patches designed for repeated use, dry electrodes are preferred because they can be cleaned and they do not require gels or adhesives that may be depleted after one or more uses. Sensor patches with dry electrodes can be in direct contact with the skin or can be worn over clothing worn by the user.

[0005] To ensure good contact between the electrodes and the user, a certain amount of pressing force needs to be applied to the sensor patch, and a stretchable strip worn by the user can be used to generate such a pressing force. The pressing force applied by the strip to the sensor patch can be considered proportional to the stretch of the strip.

[0006] It is important to know whether the amount of pressing force is the desired amount. In the case where the pressing force is too high, it may cause discomfort to the user. On the other hand, if the pressing force is too low, it may lead to poor contact between the electrodes and the skin / clothing contact, resulting in incorrect functioning of the sensor patch and unreliable measurements.

[0007] Therefore, there is a need for an improved system including a strip that can at least allow monitoring of the stretch of the strip, which indicates the amount of pressing force applied to the sensor patch. Summary of the Invention

[0008] Among other things, an object of the present invention is to provide a system and a corresponding method including a strip for positioning a sensor patch on a user, the system and the method at least allowing monitoring of the tension applied by the strip to the user. Using the system according to the present invention, the user can at least observe whether the amount of tension is the desired amount of tension, whether the strip is under-tensioned or over-tensioned, and adjust the amount of tension according to certain embodiments.

[0009] The present invention is defined by the independent claims. Advantageous embodiments are defined in the dependent claims.

[0010] A first aspect of the present invention provides a system for positioning a sensor patch on a user, the system comprising: a strip for generating a pressing force on the sensor patch when the strip is stretched, the strip including a stretchable portion and a first marker located on the stretchable portion; and a non-stretchable element having a second marker, wherein the non-stretchable element is a strip mounted on the strip, the strip having a connector or an elastic joint at one end and an elastic joint at the other end, the strip allowing the stretching of the strip even when tightened, and wherein the relative position of the first marker and the second marker indicates the amount of stretching of the stretchable portion.

[0011] The advantage is that the user can observe by visual inspection of the system whether the stretchable portion of the strip has the desired stretch. The desired stretch corresponds to the desired force, i.e., the force desired by the design required to press the sensor patch against the user. If the amount of stretch is the desired amount, the desired pressing force is achieved, thereby reducing user discomfort and ensuring proper contact between the electrodes and the user's skin or clothing, such that the sensor patch can perform electrophysiological measurements according to its specifications. If it is observed that the stretch is less than or greater than desired, the user or another person can take action to bring the stretch of the strip to the desired amount, for example by changing to another strip having a size more suitable for the user, or by adjusting the amount of stretch, for example by using fasteners.

[0012] In the case where the sensor patch can be separated from the strip and is designed such that the strip can slide on the sensor patch when the user changes position or moves, the advantage of ensuring that the strip is not over-stretched is that motion artifacts can be reduced. If the stretch of the strip exceeds the desired amount, the high pressing force can effectively fasten the sensor patch to the strip. Therefore, the sliding of the strip on the sensor patch will be hindered, resulting in misalignment of the sensor patch relative to the user's skin and the generation of motion artifacts.

[0013] The non-stretchable element is a strip mounted on a strap, such as a fabric strip or a band, which allows stretching of the strap even when tightened. The advantage is that when the strap is worn, the non-stretchable element does not limit the stretching of the strap, even in cases where the strap is stretched beyond the desired amount. Otherwise, the user could potentially tear and irreparably damage the strap, for example, when attempting to wear the strap or attempting to increase the stretch beyond the desired amount. Thus, these features implement a robust system that is less likely to be accidentally damaged by incorrect use.

[0014] The fabric of the strip can be silk, cotton, polyester, nylon or polypropylene. Such materials improve wearing comfort. In addition, such materials can be folded, and folding does not damage them. For example, when folded, they mainly undergo temporary deformation.

[0015] The advantage of the non-stretchable element being a strip is that it is bendable and foldable. Thus, a system including a strap and a strip can be easily folded and stored when not in use, thereby requiring minimal storage space.

[0016] In an embodiment, the strip is irreversibly mounted on the strap. Thus, applicability is improved because the user does not need to attach the strip to the strap. In addition, reliability is improved because there is no risk that the strip may come off or become loose. This could lead to an incorrect indication of the amount of stretch of the stretchable part.

[0017] Furthermore, the structure of the system, namely that the strip is mounted on the strap, having a connector or an elastic joint at one end and an elastic joint at the other end, ensures the integrity of the strip even after long-term use of the system, resulting in a robust system with an extended lifespan. This effect is achieved because the strip is mounted on the strap, i.e., it is attached to the strap, but it does not form a structural element of the strap. Thus, in the case where the system is under tension, i.e., when it is in use, the tension required to press the sensor patch against the user will be mainly transmitted by the strap itself rather than by the strip. That is, the strip is configured to transmit a first tension that is less than a second tension transmitted by the strap. The tension generated in the strip depends on the elasticity and the amount of stretch of one or more elastic joints used to mount the strip on the strap. For example, the first tension in the strip can be less than 10% of the second tension in the waistband, and more preferably less than 1% of the second tension.

[0018] In an embodiment, the stretchable portion may include at least two first markers that are symmetric about an axis extending along the width of the strip, and the inextensible element is mounted on the strip and has elastic joints at both of its ends, wherein the inextensible element includes at least two second markers that are symmetric about the same axis. The advantage is that by having two or more first and second markers, additional markers are provided to the user to check the stretching of the strip, thereby achieving improved applicability of the system. For example, if a pair of first and second markers is out of the user's line of sight, e.g., there is an obstacle or the body part wearing the strip may not allow easy inspection, then at least another pair of first and second markers may be visible.

[0019] According to an embodiment, the system may include a fastener for adjusting the amount of stretch of the stretchable portion. The advantage is that the user can adjust the stretching of the strip in order to achieve the desired stretch and thus the desired pressing force. In the case where the system does not include a fastener, the user is limited to observing the amount of stretch of the stretchable portion of the strip.

[0020] According to an embodiment, the strip includes an inextensible portion, wherein the stretchability of the inextensible portion is less than that of the stretchable portion, and wherein at least one of the inextensible element and the fastener is mounted on the inextensible portion. Compared to a similar connection with the stretchable portion, the material of the more rigid inextensible portion allows for a more stable and robust connection with the inextensible element and / or the fastener.

[0021] In a second aspect of the present invention, a method for positioning a sensor patch on a user is provided, the method comprising: positioning a sensor portion on the user, positioning a system as described herein on the user, and monitoring the amount of stretch of the stretchable portion of the strip indicated by the relative positions of the first and second markers.

[0022] Furthermore, in the case where the described system includes a fastener, the method also enables adjusting the amount of stretch of the stretchable portion of the strip by fixing the fastener at a desired position on the strip.

[0023] The advantages and technical effects already described for the system also apply to the corresponding method.

[0024] These and other aspects of the present invention will be apparent and elucidated with reference to the embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1a-1d An example of a system for positioning a sensor patch on a user according to the present invention is shown.

[0026] Figure 2a-2d Shows another example of a system for positioning a sensor patch on a user according to the present invention.

[0027] Figure 3a-3b Shows an example of a system for positioning a sensor patch on a user according to the present invention.

[0028] Figure 4 Shows a flowchart of a method for positioning a sensor patch on a user according to the present invention. Detailed Description

[0029] The present invention will be described with reference to the accompanying drawings. When indicating exemplary embodiments of the present invention, the detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present invention. These and other features, aspects, and advantages of the present invention will be better understood from the following description, the appended claims, and the drawings. The drawings are merely schematic and not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to indicate the same or similar parts.

[0030] The present invention provides a system and method for positioning a sensor patch on a user. The sensor patch can be used for electrophysiological measurements, for example, based on electrocardiogram (ECG), electroencephalogram (EEG), or electrocardiotocogram (eCTG). The part of the user's body where the sensor patch should be positioned depends on the measurement to be performed. For example, a sensor patch for monitoring ECG should preferably be placed at the chest area of the user, a sensor patch for monitoring EEG should preferably be placed on the head of the user, and a sensor patch for pregnancy monitoring should be placed on the abdomen of the user.

[0031] Figures 1a to 1d Shows a system 10 for positioning a sensor patch on a user. The system 10 includes a strip 20 having a stretchable portion 22 in which a first marker 25 is located. The system also includes a non-stretchable element 30 having a second marker 35. In Figures 1a to Figure 1d this case, the non-stretchable element 30 is a strip. The length of the non-stretchable element 30 changes substantially not under tension, for example, its increase is less than 5% of the length it has in the non-tensioned position, preferably less than 2%, and more preferably less than 1%.

[0032] When the strip 20 (e.g., a waistband) is stretched, the strip 20 exerts a pressing force on the sensor patch, thereby keeping the sensor patch positioned on the user. The sensor patch can include wet electrodes, semi-dry electrodes, or dry electrodes.

[0033] The stretchable portion 22 of the strip 20 can be made of any suitable material having stretchable properties (such as stretch fabric), for example nylon, spandex, neoprene. Preferably, the stretchable portion 22 of the strip 20 is made of a material suitable for clothing and / or is washable. The stretchable portion 22 can be stretched in only one direction (i.e., longitudinally or transversely), or in two directions (i.e., both longitudinally and transversely). Preferably, when the strip 20 is not stretched, the stretchable portion 22 at least partially returns to its original position. The stretchable material is capable of stretching more than 20% of its width and / or length in the non-stretched position, preferably more than 40%, and even more preferably in the range between 30% and 60%, without losing its ability to at least partially return to its non-stretched position.

[0034] Each of the disclosed ranges regarding the stretchability of the stretchable portion 22 can be combined with each of the disclosed ranges regarding the non-stretchability of the non-stretchable element 30.

[0035] To protect the stretchable material from stretching beyond the point where it may be damaged, the stretchable portion 22 can include a protective element, such as a strip. The protective element can limit the stretchable portion 22 from stretching more than 100% to 120% of its width and / or length in the non-stretched position.

[0036] As Figures 1a to Figure 1d shown, the system 10 can include a fastener 40 for fastening the strip around a portion of the user's body. For example, the fastener can be a buckle, a button, a hook-and-loop fastener, or any other known module. However, as Figure 3a further explained, the fastener is not necessary for the operation of the present invention.

[0037] Figures 1a to Figure 1d It is shown that the system 10 can also include a non-stretchable portion 21. The stretchability of the non-stretchable portion 21 is less than that of the stretchable portion 22 of the strip 20. For example, it is capable of stretching less than 20% of its width and / or length in the non-stretched position, preferably less than 10%, and more preferably less than 5%.

[0038] In Figures 1a to Figure 1d it, the non-stretchable element 30 is a strip mounted on the non-stretchable portion 21 of the strip 20, which has a connector 55 at one end and an elastic joint 51 at the other end. The elastic joint 51 is made of an elastic material (such as rubber) that elongates when tightened.

[0039] Alternatively, the strip can be mounted on the stretchable portion 22 of the strip 20 at both ends. For example, it has a connector 55 at one end to fasten the strip to the stretchable portion 22, and an elastic joint 51 at the other end, where the elastic joint 51 is also fastened to the stretchable portion 22. Other solutions are also possible, where one end of the non-stretchable element 30 is connected to the non-stretchable portion 21 and the other end is connected to the stretchable portion 22.

[0040] Figure 1a The system 10 is shown in the non-tensioned position, where no tension is applied to the system.

[0041] After applying sufficient tension to the system, the strip is straightened, as Figure 1b shown. Even when the strip is tightened, the elastic joint 51 allows the stretching of the strip 20, that is, the stretching of the strip is not limited to the length of the strip.

[0042] The relative position of the first marker 25 located on the stretchable portion 22 of the strip 20 and the second marker 35 located on the non-stretchable element 30 indicates the amount of stretching of the stretchable portion 22. When the stretchable portion 22 of the strip 20 is stretched, its length increases, and the position of the first marker 25 changes relative to the second marker 35. In the initial position, for example, the stretchable portion 22 is in the position as Figure 1b shown, where the stretchable portion is stretched enough to straighten the strip, and there is a distance d between the first marker 25 and the second marker 35. As the stretching increases, the first marker 25 moves closer to the second marker 35, and the distance d between the first marker 25 and the second marker 35 decreases. At the point where the distance d becomes zero, the first marker 25 and the second marker 35 coincide, and this is the point where the amount of stretching is the desired amount.

[0043] The first marker 25 and the second marker 35 are shown in the figure as having relatively small sizes, but this is only depicted for illustrative purposes. One of the first marker 25 and the second marker 35 can have a larger size than the other. For example, the second marker 35 can have a larger width than the first marker 25. In this example, the desired amount of stretching is not limited to a certain point where the first marker and the second marker coincide, but to a certain stretching range. For example, when the first marker 25 reaches one end of the second marker 35 and as the stretching increases and the first marker 25 continues to move relative to the second marker 35, the desired amount of stretching is obtained, and the stretching is considered desired until the point where the first marker reaches the other end of the second marker 35.

[0044] As the stretching continues, after the first marker 25 has reached the second marker 35, i.e., after the desired amount of stretching has been achieved, the distance d between the first marker 25 and the second marker 35 increases again, as Figure 1d shown. In Figure 1d , the strip 20 is shown in an overstretched position because it has exceeded the desired stretch, and in Figure 1b , the strip 20 is shown in an understretched position because it has not yet reached the desired stretch.

[0045] The first marker 25 and the second marker 35 are preconfigured to coincide with the positions of the stretchable portion 22 of the strip 20 having the desired stretch. The desired stretch corresponds to the desired force, i.e., the force desired by the design, and is the force required to press the sensor patch against the user when the system 10 is worn. In an example, the desired force applied to each electrode of the sensor patch is at least 0.1 N, preferably at least 0.5 N, and more preferably at least 1 N. Additionally or alternatively, in the case where the sensor patch has 13 electrodes and the desired force applied to each electrode is, for example, 0.5 N, a pressing force of at least 13 x 0.5 = 6.5 N is required. Since not all of the pressing force of the belt will be distributed to the electrodes, the desired force applied to the sensor patch from the strip 20 should, for example, be doubled, so it should be at least 13 N. In a non-limiting example, the desired force is a force that meets the following requirements: i. It includes a vector perpendicular to the user's skin that presses the sensor patch against the user such that at least one electrode of the sensor patch can make measurements as expected; ii. The sensor patch remains positioned on the user even when the user changes position or moves; and iii. It does not cause long-term discomfort to the user.

[0046] The system 10 can also be considered to work as a scale. For example, by observing the relative positions of the first marker 25 and the second marker 35, such as the distance d in Figure 1b and 1d , the user can estimate how much additional / less stretching is needed to reach the desired amount of stretch.

[0047] The first marker 25 and the second marker 35 can be printed, stitched, or pulled. Additionally or alternatively, instead of being visually perceived by the user, they can also be markers perceived by touch, such as protrusions or markers having unique tactile properties. Additionally or alternatively, auditory guidance can also be used to notify the user or a third party of the relative positions of the first marker and the second marker. The latter two exemplary solutions will be particularly helpful for visually impaired users.

[0048] System 10 may have two or more first markers 25 on strip 20 and two or more second markers 35 on non-stretchable element 30. In such an example, a first marker 25 and a corresponding second marker 35 form a pair of first and second markers 25 and 35, and additional first and second markers form additional corresponding pairs of first and second markers. If the first marker 25 and the corresponding second marker 35 coincide at a position where the strip 20 has a desired amount of stretch, they form a pair of first and second markers.

[0049] Figures 2a to 2d Another example of system 10 is shown. Similar to Figures 1a to 1d the system 10 shown, system 10 includes a strip 20 having a stretchable portion 22 and a non-stretchable portion 21. It also includes a fastener 40. The non-stretchable element 30 is a strip. Figures 2a to 2d The non-stretchable element 30 in

[0050] Similar to Figures 1a to 1d the example shown, the non-stretchable element 30 is mounted on the non-stretchable portion 21, but it can also be mounted on the stretchable portion 22. In Figures 2a to 2d it, the non-stretchable element 30 is mounted on the strip and has elastic joints 51a and 51b at both of its ends.

[0051] Figure 2a System 10 in a non-tensioned position is shown, where no tension is applied to the system. Figure 2b System 10 is shown understretched but stretched enough to straighten the strip and the elastic joints 51a and 52b. Figure 2c System 10 is shown where the stretchable portion 22 is under the desired stretch because the first markers 25a and 25b coincide with the second markers 35a and 35b. Figure 2d System 10 is shown where the stretchable portion 22 is overstretched.

[0052] In Figures 2a to 2d the example shown, the first markers 25a and 25b are symmetric about an axis extending along the width of the strip, and the second markers 35a and 35b are symmetric about the same axis. The axis can be chosen, for example, to pass through the middle or other point of the non-stretchable element 30. Thus, ensuring that the first markers 25 and the second markers 35 are symmetrically aligned. The user can query the relative positions of any pair of markers (i.e., first marker 25a compared to second marker 35a or first marker 25b compared to second marker 35b) to check the stretch of the stretchable portion 22.

[0053] Figures 1a to 2d Shows a strip 20 having edges configured to be fastened together using fasteners 40. As already indicated, the fasteners 40 may not be used. Figure 3a Shows an example where the strip 20 can form a closed loop, for example can be tubular, without edges configured to be fastened together. Such a strip can be worn, for example, by pulling it through a leg or a head such that it can be worn around the torso or around one of the limbs of a human body.

[0054] In the case where the strip 20 includes fasteners 40, the strip 20 can have only one size, for example a large size. The strip 20 is worn around a part of the user's body (such as the abdomen), and using the fasteners 40, the amount of stretch can be adjusted. On the other hand, in the case where the strip 20 does not include fasteners 40, as Figure 3a shown, depending on the size of the user for whom the strip is to be worn, more than one size of the strip 20 can be available. The user can wear the strip 20, and if the system indicates that the amount of stretch is not the desired amount of stretch, the user can wear another strip 20 of a different size (such as diameter) whose size indicates that its amount of stretch is the desired amount of stretch. In another example, the same pregnant user may require more than one size of strip 20 without fasteners 40 for eCTG measurements. As the pregnancy progresses, the size of the user's abdomen increases and thus may require a larger strip 20 without fasteners to maintain the desired amount of stretch of the strip holding the sensor patch in place.

[0055] Figure 3a and 3b shows that the strip 20 includes only a stretchable portion 22, however, it may also include a non-stretchable portion. Additionally, the solutions shown in these figures for indicating the desired stretch of the stretchable portion 22 are similar to the Figures 2a to 2d solutions described in. However, all Figures 1a to 2d solutions described in can be implemented with a tubular strip or any other strip whose edges are not configured to be fastened together.

[0056] Figure 3b shows that in the case of a tubular strip 20, fasteners 40 can also be used, thus allowing the user to adjust the stretch of the stretchable portion 22 of the strip 20.

[0057] Figures 1a to 3a The example shown shows a system 10 having one non-stretchable element 30. However, more than one non-stretchable element can be used simultaneously in the same system 10, such as one or more straps.

[0058] Figure 4A flowchart of a method for positioning a sensor patch on a user according to the present invention is shown. In step 101, the sensor patch is positioned on the user. The sensor patch can be positioned on any part of the user's body according to the measurement to be performed. For example, a sensor patch designed to monitor eCTG should be placed on the user's abdomen. In step 102, the user places the system 10, as already described herein, on the sensor patch. Thus, even when the user changes position or moves, the system 10 provides the force necessary to keep the patch positioned on the user. In an example, the sensor patch is configured to be fastened to the system 10. For example, the sensor patch is configured to be sewn or hooked onto the strip 20.

[0059] After positioning the sensor patch and the system 10 on the user, in step 103, the user and / or a third party can monitor the amount of stretch of the stretchable portion of the strip indicated by the relative position of the first marker and the second marker, as already explained herein. In the case where the system 10 includes the fastener 40, in an optional step 104, the user and / or a third party can also adjust the amount of stretch of the stretchable portion 22 of the strip 20 by fixing the fastener 40 at a desired position on the strip 20. For example, if the strip 20 is under-stretched, the user can increase the stretch of the strip 20 to the point where the relative position of the first marker 25 and the second marker 35 indicates the desired stretch. Similarly, in the case where the strip 20 is over-stretched, the user can reduce the stretch of the strip 20 to the point where the relative position of the first marker 25 and the second marker 35 indicates the desired stretch.

[0060] In summary, a system 10 for positioning a sensor patch on a user is provided. The system includes a strip 20 and a non-stretchable element 30. The strip 20 is configured to generate a pressing force on the sensor patch when the strip is stretched. The strip includes a stretchable portion 22 and a first marker 25 located on the stretchable portion. The non-stretchable element 30 has a second marker 35. The non-stretchable element 30 is a strip mounted on the strip 20. The strip has a connector 55 or an elastic joint 51b at one end and elastic joints 51, 51a at the other end. The strip allows the stretch of the strip even when tightened. The relative position of the first marker and the second marker indicates the amount of stretch of the stretchable portion. The user guided by the relative position of the first marker 25 and the second marker 35 can act on the stretchable portion 22 of the strip to achieve a desired stretch, which corresponds to a desired pressing force on the sensor patch. A corresponding method 100 for positioning a sensor patch on a user is also provided.

[0061] It should be noted that the above embodiments illustrate rather than limit the present invention, and those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising several distinct elements and / or by means of a suitably programmed processor. In device claims enumerating several modules, several of these modules may be embodied by the same item of hardware. The measures recited in mutually different dependent claims may advantageously be used in combination.

Claims

1. A system (10) for positioning a sensor patch on a user, the system include: A strip (20) for generating a compressive force on the sensor patch when the strip is stretched, the strip comprising a stretchable portion (22) and a first marker (25) located on the stretchable portion, and A non-stretchable element (30) having a second marker (35), wherein: The non-stretchable element (30) is a belt mounted on the strip (20), the belt having a connector (55) or an elastic joint (51b) at one end and an elastic joint (51, 51a) at the other end, the belt allowing the stretching of the strip even when tightened, and wherein: The relative position of the first marker and the second marker indicates the amount of stretch of the stretchable portion.

2. The system according to claim 1, in, The ribbon is irreversibly mounted on the strip.

3. The system according to claim 1 or 2, in, The ribbon is configured to impart a first tension that is less than a second tension imparted by the strip.

4. The system according to claim 1 to 3, in: The stretchable portion (22) comprises at least two first markers (25a, 25b) symmetrical about an axis extending along the width of the strip (20), and The non-stretchable element (30) is mounted on the strip and has elastic joints (51a, 51b) at both ends of the non-stretchable element, wherein the non-stretchable element includes at least two second markers (35a, 35b) symmetrical about the same axis.

5. The system according to claim 1 to 4, in, The strap (20) includes a fastener (40) for adjusting the amount of stretch of the stretchable portion (22).

6. The system according to claim 1 to 5, in, The strip (20) includes a non-stretchable portion (21), wherein the non-stretchable portion is less stretchable than the stretchable portion (22), and wherein at least one of the non-stretchable element (30) and the fastener (40) is mounted on the non-stretchable portion.

7. A method (100) for positioning a sensor patch on a user, the method include: positioning (101) the sensor patch on the user, positioning (102) a system (10) according to any one of claims 1 to 6 on the user, and The amount of stretch of the stretchable portion of the strip indicated by the relative position of the first marker (25) and the second marker (35) is monitored (103).

8. The method according to claim 7, wherein include: positioning (102) a system according to claim 5 on the user, and The amount of stretch of the stretchable portion of the strap is adjusted (104) by securing the fastener at a desired location on the strap.

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