JP2013244027A - Muscular active mass measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a muscular active mass measuring device for measuring the distribution of the muscular active mass of the inside of the body and the muscular active mass for each of muscles from a surface myogenic potential signal in which the myogenic potential of many muscles overlaps.SOLUTION: A surface myogenic potential simulation value at the position of a surface electrode in a surface myogenic potential simulation section is calculated with the following in mind: (A) a myogenic block region obtained by dividing a circular cross section of a substantially cylindrical shape part of a body into small parts of ≤5 mm by finite element division, and (B) a virtual muscle fiber divided into small parts ≤1/2 of the muscle block and forming the muscle block.

Description

The present invention relates to a method for measuring the amount of muscle activity in the body, and relates to an apparatus for measuring the amount of muscle activity inside the body from the intensity and intensity distribution of surface myoelectric potential.

As a means for measuring the amount of muscle activity in the body, an electromyograph that measures a bioelectric potential (muscle action potential) generated when the muscle is active is often used. The main types of electromyographs are needle electromyographs that measure by inserting an electrode needle into the muscle, and surface electromyographs that measure by attaching a surface electrode to the skin directly above the muscle. Except for special fields such as non-invasive, painless and simple surface electromyography is desirable.

The amount of muscle activity can be electrically measured as the sum of muscle action potentials generated by muscle fibers. This sum represents the activity frequency of muscle fibers inside the muscle and is approximately proportional to the muscle contraction force. The amount of muscle activity is generally calculated from the time root mean square value of the muscle action potential, the so-called effective value. Since the surface myoelectric potential increases in proportion to the amount of muscle activity, the amount of muscle activity can be calculated from the surface myoelectric potential using the same calculation method.

However, the surface electromyograph has a problem that all the muscle action potentials of the muscles around the electrodes are superimposed and measured. In particular, a portion where many muscles such as the forearm and the lower leg are densely gathered in a narrow region has a large overlap, making it difficult to measure a specific muscle.

Therefore, the inventors measured the distribution of the surface myoelectric potential by attaching a large number of surface electrodes in a circular columnar part of the body, such as the forearm and the lower leg, and measured the distribution of the surface myoelectric potential using an internal electrical conduction simulation model. The invention described in Japanese Patent Application Laid-Open No. 2011-30991 for calculating the amount of muscular activity was performed. According to the present invention, it has been possible to measure individual muscle activities in a dense muscle region using a surface electromyograph, which has been difficult in the past.

JP 2011-30991 A

In the electrical conduction simulation model according to the invention described in Patent Document 1, it is assumed that one muscle has a uniform activity of muscle fibers in the region. The measurement site | part was image | photographed in advance by MRI etc., the area | region of each muscle was specified, and the activity of the muscle fiber was calculated based on this assumption.

However, in the anatomical physiology of muscles, it has been found that one muscle may be controlled by different nerves. For example, the deep finger flexor is governed by two different nerves, the median nerve and the ulnar nerve. In this case, the muscles do not always work uniformly within the same muscle region. In other words, the method of the present invention has a problem that even if the muscle region is specified in advance, the simulation by the model and the actual distribution of the muscle activity amount may be different.

There was also a problem that the calculation of muscle activity of deep muscles often diverges. This is because the conduction of the muscle action potential of the deep muscle is extremely weak. This divergence is caused by an extreme difference in the amount of surface myoelectric potential conduction between the deep muscle and the surface muscle. Since the ratio of the surface myoelectric potential of the deep muscle, which has a large attenuation, and the surface myoelectric potential of the surface muscle, which has a small and strong attenuation, is extremely different, the calculation of the deep muscle has become extremely sensitive to minute measurement noise.

Therefore, in order to solve these problems, the present invention provides a muscle activity amount measuring apparatus that measures the distribution of muscle activity amount by dividing the inside of the body into fine muscle block regions without specifying individual muscle regions. provide.

The first invention of the present invention is:
A surface electrode arranged in a ring around the approximately cylindrical part of the body,
A muscle activity measuring device having a surface myoelectric potential measuring unit for measuring a surface myoelectric potential in the surface electrode,
A surface myoelectric potential simulation unit for calculating a surface myoelectric potential simulation value at the position of the surface electrode from a muscle activity amount of a muscle in a cross section at a position where the surface electrodes of the substantially cylindrical portion of the body are arranged in an annular shape;
The surface myoelectric potential simulation value at the position of the surface electrode calculated by the surface myoelectric potential simulation unit and the surface myoelectric potential at the position of the surface electrode measured by the surface myoelectric potential measurement unit are roughly matched. A muscle activity amount estimation unit that adjusts the amount of muscle activity in the cross section and estimates the muscle activity amount when roughly matching the muscle activity amount in the body;
Comprising
The calculation of the surface myoelectric potential simulation value at the position of the surface electrode in the surface myoelectric potential simulation unit is as follows.
(A) A muscle block region obtained by finely dividing a circular cross section of a substantially cylindrical part of the body into 5 mm or less by finite element division, and (b) less than ½ of the width of the muscle block region constituting the muscle block region. Assuming finely divided virtual muscle fibers,
The time square average value of the surface myoelectric potential due to the muscle activity of the virtual muscle fiber is calculated from the time square mean value of the muscle activity amount of the virtual muscle fiber, and the virtual muscle is calculated for the muscle block region in the transverse section. The muscle activity amount measuring apparatus is characterized in that the surface myoelectric potential simulation value is calculated by taking a square root of a sum of time square average values of surface myoelectric potentials based on fiber muscle activity amount.

The second invention of the present invention is:
The muscle activity amount estimation unit calculates a muscle activity amount of a virtual muscle fiber in the transverse section when a surface myoelectric potential simulation value at the position of the surface electrode and a surface myoelectric potential at the position of the surface electrode approximately coincide with each other. 1 is a muscle activity amount measuring apparatus according to a first aspect of the present invention, which estimates the amount of muscle activity of a virtual muscle fiber in the inside.

According to a third aspect of the present invention, when the muscle activity amount estimating unit adjusts the muscle activity amount of the virtual muscle fiber, the muscle activity amount of the virtual muscle fibers belonging to the same muscle block region is made the same, It is a muscle activity amount calculation apparatus according to the second aspect of the invention for calculating a surface myoelectric potential simulation value.

The fourth aspect of the present invention is the muscle activity measuring device according to any one of the first to third aspects of the present invention, wherein the size of the muscle block region is fine near the outer periphery of the cross section and increases toward the approximate center. .

According to a fifth aspect of the present invention, the surface electrode is a bipolar electrode in which two electrodes are paired, and two or more bipolar electrodes having different distances between the two electrodes are the centers of the two electrodes. It is the muscle activity amount measuring device according to any one of the first to fourth aspects of the present invention, which is arranged so that the midpoints of the line segments connecting the parts roughly coincide.

According to the present invention, an electrical conduction simulation model in the body in which the inside of the body is divided into fine muscle block regions without specifying the individual muscle regions from the surface myoelectric potential in which the myoelectric potentials from the muscles are complicatedly superimposed. It becomes possible to determine the distribution of the amount of muscle activity inside the body.

It is the model which has measured the distribution of the surface myoelectric potential on the cross section 25 of a forearm with the bipolar electrode. FIG. 6 is a cross-sectional view of the forearm in the cross section 25. It is a schematic diagram which shows the construction method of the electrical conduction model of a forearm. It is a flowchart of the method of calculating a muscle activity amount using the said simulation model from a human surface myoelectric potential. It is a muscle activity amount measurement result when only a narrow electrode is used. FIG. 5 is a schematic diagram in which a bipolar electrode having a narrow interval and a bipolar electrode having a wide interval are arranged on a cross section 25 of the forearm and a distribution of surface myoelectric potentials on the cross section 25 of the forearm is measured. It is a muscle activity amount measurement result of the muscle area | region by the conventional MRI imaging | photography. It is a muscle activity amount measurement result at the time of using two types of electrodes of a narrow space | interval and a wide space | interval. It is a block diagram of a muscular activity amount measuring device.

Hereinafter, embodiments of the present invention will be described by way of examples.

FIG. 1 shows an example of a muscle activity amount measuring apparatus of the present invention.
As shown in FIG. 1, it is assumed that the bipolar electrode 22 is annularly arranged on the skin surface on the cross section 25 of the forearm with the center line 26 of the forearm as a general line. The bipolar electrode is an electrode for measuring the differential voltage of a pair of two single electrodes. The bipolar electrode 22 of FIG. 1 is a bipolar electrode formed by a pair of single electrodes arranged in parallel with the center line 26. ing. The bipolar electrodes are arranged in n rows at approximately equal intervals in the circumferential direction of the forearm. In order to improve the calculation accuracy of the amount of muscle activity, it is better that the number of electrode arrangements is larger. Numbers i = 1... N are assigned to the bipolar electrodes for convenience.

A surface myoelectric measurement unit 24 is connected to the bipolar electrode via an electrode cable 23, and the surface myoelectric potential on the cross section 25 is measured by these.

Next, the construction method of the electrical conduction simulation model in the body will be described. The circumference of the forearm in the cross section 25 of the measurement subject is measured, and a circular section having the same diameter is formed. At this time, the outline 13-1 of the muscle block region is formed on the inner side by the skin fat thickness measured by a caliper or the like from the outline 17 on the forearm surface. Although an example of a circular cross section is shown here, an oval cross section or an accurate cross sectional shape obtained by tomography may be used as long as the forearm shape is simulated.

Next, the muscle block region 13 is configured by finely dividing the outline 13-1 of the muscle block region so as to gradually increase from the surface toward the deep layer. At this time, it is desirable that the size of the division is approximately 5 mm or less. However, if the division is too fine, the calculation speed is reduced, so that it is preferably approximately 1 mm to 5 mm. The division is more preferable if the surface layer is approximately 1 mm and the vicinity of the center is approximately 5 mm and the size is gradually changed from the surface layer to the center. The distance between the electrode and the muscle block region is near in the surface layer and far in the deep layer. As this distance increases, the myoelectric potential conduction amount decreases rapidly. If muscle block regions having the same size are formed on the surface layer and the deep layer, the contribution rate of the deep muscle block region muscle activity to the surface potential becomes extremely small, and the calculation of the muscle activity amount is likely to diverge. Therefore, by increasing the deep muscle block region, the contribution rate to the surface potential is increased, and the muscle activity amount calculation is facilitated. The reason why the maximum size of the muscle block region is set to about 5 mm is to make the block fit within the width of the smallest muscle in the forearm.
This muscle block region can be created by, for example, the following Voronoi diagram. First, the mother points are arranged uniformly at equal intervals, for example, 1 mm, on the circumference of the surface layer. Next, the mother points are arranged so that the point intervals gradually spread toward the center direction and are evenly scattered. After this, according to the algorithm of the Voronoi diagram, a perpendicular bisector that equally divides between adjacent generating points is created and divided into regions centered on the generating points. That is, the region in the plane belongs to the nearest generating point. Divide like so.
FIG. 2 shows an example of a Voronoi diagram of the muscle block region. The muscle block area is divided into a total of 805 muscle block areas with a surface of 1 mm and a center area of 4 mm.

Further, the inside of the outline 13-1 of the muscle block region is divided into smaller sized virtual muscle fibers 14.
Here, the reason why the virtual muscle fiber is used is that it is assumed that each muscle block region is formed by aggregation of the virtual muscle fibers. At this time, it can be assumed that the amount of activity of virtual muscle fibers in each muscle block region is equal. The size of this division is 20 μm to 2 mm, which is the actual muscle fiber diameter, and depends on the minimum size of the muscle block region. In general, it is desirable to set it to 1/2 or less of the size of the muscle block region. However, if the division is too fine, the calculation speed is reduced. Therefore, it is desirable to divide the input into about 1/2 to 1/10. For example, when the minimum size of the muscle block region is 1 mm, it is desirable that the division of the virtual muscle fiber is approximately between 0.1 mm and 0.5 mm.
If the size of the virtual muscle fiber is large, the shape of the muscle block region cannot be expressed correctly, which is not preferable. On the other hand, if it is small, the memory and time required for calculation become enormous, which is not preferable.
FIG. 3 schematically shows a state in which the outline 13-1 is divided into the muscle block region 13 and the virtual muscle fiber 14. As shown in FIG.

Next, numbers are assigned to the muscle block region 13 and the virtual muscle fiber 14 in the cross section, respectively. Assuming that the muscle number of the muscle block region 15 is j, the number of the virtual muscle fiber 14 in the muscle block region 15 is k, and the position vector of the virtual muscle fiber k in the muscle j is represented as _xMjk . On the surface of the model, the virtual bipolar electrode 11 is assumed to be located at the same position as the bipolar electrode 22 arranged on the actual forearm, and the same number as the bipolar electrode arranged on the body is assigned. Let the number of the electrode 12 be i and its position vector be _xEi . When the surface electrode-virtual muscle fiber distance 16 is L _ijk , L _ijk is represented by x _Mjk and x _Ei and the vector norm symbol ||. . . Using ||, it can be expressed as in Equation 1. At this time, the distance between the surface electrode and the virtual muscle fiber refers to the distance from the midpoint of the line segment connecting the centers of the single electrodes constituting the bipolar electrode to the center of the virtual muscle fiber. Hereinafter, when the position of the bipolar electrode is indicated, it indicates the midpoint of a line segment connecting the centers of the single electrodes.

Here, when the direction of the muscle fibers in the substantially cylindrical body part is substantially aligned with the direction of the central axis, the virtual muscle fiber k in the muscle block j is the time-square mean value of the amount of muscle activity (hereinafter referred to as the muscle activity amount). , MS value) The time-square mean value V _ijk ² of the surface myoelectric potential generated on the surface electrode i when active at m _jk ² is attenuated to the power with respect to the surface-virtual muscle fiber distance L _ijk . It shall be. The relationship between V _ijk ² and m _jk ² is that the unit muscle activity amount RMS value m when the number 1, m _jk , L _ijk, and the attenuation multiplier b for L _ijk , and the unit surface-virtual muscle fiber distance L ₀ = 1 mm It is expressed as follows as a transfer function using a coefficient V ₀ which is a root mean square value (hereinafter referred to as RMS value) of surface EMG at _jk = 1. Note that b and V ₀ are constants determined by the distance between the electrodes constituting the bipolar electrode, and the RMS value is the square root of the MS value.

Here, assuming that all virtual muscle fibers in the same muscle block region have the same amount of muscle activity, and all the virtual muscle fibers in the muscle j have the same RMS value m _j , the surface muscle of the muscle j at the electrode i The potential MS value V _ij ² can be calculated as follows from _Equation ^{2 as} the sum of V _ijk ² .

L _{Sij in Expression} 3 is referred to as a total transmission coefficient for the electrode i of the muscle j. Furthermore, since the surface myoelectric potential MS value V _i ² of the electrode i is the sum of the MS values of all the muscles, it is expressed by the following equation from Equation 3.

Formula 4 is a simulation calculation formula of the surface myoelectric potential by the electric conduction simulation model of the present invention. As a result, the surface myoelectric potential when each muscle is active at each muscle activity amount can be calculated on the model.

Next, a method for calculating the amount of muscle activity using a human surface myoelectric potential and the electric conduction simulation model will be described. The surface myoelectric potential MS value measured by the surface electrode i on the forearm of the measurement subject corresponding to the virtual electrode i on the model is defined as V _Mi ² .

Hereinafter, the calculation method will be described with reference to the flowchart of FIG. At the beginning of the calculation, the initial value of the muscle activity amount m _j of each muscle in the model formula of Equation 4 is appropriately determined in advance as shown in S21. The initial value of m _j is set so as to be between 0 and the theoretical maximum value so that the calculation does not diverge, for example, about 10% of the maximum value.

Next, as shown in S22, the simulation surface myoelectric potential RMS value V _i is calculated by the simulation formula of Formula 4.

From this, the difference e _i between the surface myoelectric potential RMS value V _Mi measured on the human forearm and the simulated surface myoelectric potential RMS value V _i is calculated as follows.

Several 5 e _i, is calculated as follows evaluation function f of the difference as shown to step S23 as the sum of squares of the difference between the RMS value.

The evaluation function f is calculated, and it is determined whether or not this f is almost minimum as shown in S24. f is If not approximate minimum repeated to recalculate the muscle activity m _j value appropriately changed back to S22 by simulation EMG RMS values V _i of, as shown in S25. When f is approximately the minimum, it is considered that the distribution of the surface myoelectric potential RMS value measured on the human forearm and the simulation surface myoelectric potential substantially coincide with each other, and as shown in S26, the muscle activity MS value m _j of the model Is the MS activity value of the human forearm.

Next, using the muscular activity measuring apparatus of the present invention, as shown in FIG. 1, bipolar electrodes (20 rows) were installed on the cross section 25 of the forearm with an electrode interval of 10 mm, and the muscular activity was measured. Here, for the muscle block area, a Voronoi diagram was created as shown in FIG. 2, and the muscle block area was divided into a total of 805 muscle block areas with a surface of 1 mm and a central area of 4 mm. The size of the virtual muscle fiber was 0.2 mm.
In the experiment, bending load was applied to the proximal phalangeal joint of the middle finger. The forearm, palm, and middle finger base were fixed with a band, and the middle finger was tied at a constant load in a direction opposite to the palm. At this time, the test subject was instructed to stand the finger in a fixed posture against the load.
The results are shown in FIG. In the figure, the amount of muscle activity is indicated by shades of black and white, and the whiter the activity is. This result indicates that the amount of activity in the superficial digital flexor muscle and total finger extensor muscle regions is high, and it can be seen that the muscle activity amount can be measured by the muscle activity amount measuring device of the present invention.

In the first embodiment, the muscle activity amount calculation method using a bipolar electrode having one kind of electrode interval has been described. However, if a plurality of types of bipolar electrodes having different electrode intervals are arranged in the central axis direction of the forearm, the first embodiment can be used. Detailed muscle activity can be measured.

In this embodiment, as shown in FIG. 6, a narrowly-spaced bipolar electrode 22a and a wide-spaced bipolar electrode 22b are arranged on the cross section 25 of the forearm 21, and the surface myoelectric potential obtained from each bipolar electrode is measured on the surface. Measurement is performed by the myoelectric potential measuring unit 24.

At this time, the attenuation multiplier b and the coefficient V ₀ are constants determined by the electrode interval between the bipolar electrodes, and it is known that the attenuation becomes gentler as the electrode interval between the bipolar electrodes becomes wider. At this time, attenuation multipliers and coefficients for bipolar electrodes with a narrow electrode interval are set to b _N and V _0N , and attenuation multipliers and coefficients for bipolar electrodes with a wide electrode interval are set to b _W and V _0W .

When the virtual electrodes on simulation models were the same arrangement as the bipolar electrodes on the forearm 21, the relationship between muscle activity and surface myoelectric potential of the virtual muscle fibers, having 2 to number 4 b and V ₀ and the sum transfer coefficient L _Sij can be calculated by substituting b _N , V _0N and L _{NSij for} a bipolar electrode having a narrow electrode spacing, and b _W , V _0W and L _WSij for a bipolar electrode _having a wide electrode spacing. Surface myoelectric potential RMS values V _Nijk , V _Nij , and V _Ni in bipolar electrodes having a narrow electrode interval corresponding to _Equations 2 to 4, and surface myoelectric potential RMS values V _Wijk , V _Wij , and V _Wi in bipolar electrodes having a wide electrode interval. Is expressed by the following equation.

Equations (9) and (12) are the calculation formulas for the surface myoelectric potential based on the electrical conduction simulation model when the narrowly spaced bipolar electrodes and the widely spaced bipolar electrodes are arranged.

The difference _{e i} between the human of the difference between the bipolar electrode EMG RMS value _{V MNi} and _{V Ni} narrow interval as measured by forearm, and broad bipolar electrode EMG RMS value _{V MW i} intervals and _{V Wi} in this embodiment Is defined as:

In the following, the muscle activity amount MS value of the human forearm is calculated by the same method as the method of calculating the muscle activity amount in the first embodiment.

Next, using the muscular activity measuring apparatus of the present invention, bipolar electrodes (20 and 20 mm, respectively) with a narrow interval (15 mm) and a wide interval (45 mm) on the cross section 25 of the forearm as shown in FIG. Column) and muscle activity was measured. Here, for the muscle block area, a Voronoi diagram was created as shown in FIG. 2, and the muscle block area was divided into a total of 805 muscle block areas with a surface of 1 mm and a central area of 4 mm. The size of the virtual muscle fiber was 0.2 mm.
The experiment applied flexion to the proximal phalangeal joint of the middle finger in the same manner as described in Example 1.
The results are shown in FIG. In the figure, the amount of muscle activity is indicated by shades of black and white, and the whiter the activity is. This result indicates that the amount of activity in the superficial digital flexor muscle and total finger extensor muscle regions is high, and it can be seen that the muscle activity amount can be measured by the muscle activity amount measuring device of the present invention.
When this calculation result (FIG. 7) is compared with the case (FIG. 5) in which the electrode interval of Example 1 is limited to a narrow interval (15 mm) (FIG. 5), FIG. Calculated. On the other hand, it can be seen that FIG. 7 shows that the muscle activity near and far from the electrodes can be accurately calculated by using two types of electrodes.
Therefore, when bipolar electrodes with a plurality of electrode intervals are used simultaneously as in this embodiment, the amount of muscle activity in the muscles near the electrodes can be calculated in detail because bipolar electrodes with a narrow electrode interval have a large attenuation. Since the attenuation of the electrode is small, the muscle activity in the deep part can be calculated in a wide range, so that a detailed and wide range of muscle activity can be measured.

Next, the measurement by the muscle activity amount measuring device of the present invention was compared with the measurement by the conventional muscle activity amount measuring device (Japanese Patent Laid-Open No. 2011-30991).
FIG. 8 shows a conventional method, that is, a muscle region extracted on the basis of an MRI image and measured. On the cross-section 25 of the forearm, bipolar electrodes are separated at a narrow interval (15 mm) and a wide interval (45 mm). (Each 20 rows) was installed, and the amount of muscle activity was measured. In the experiment, bending was added to the proximal phalangeal joint of the middle finger in the same manner as described in Example 1.
Comparing FIGS. 5 and 7 with FIG. 8, the muscle activity positions are almost the same, indicating the effectiveness of the muscle activity amount measuring apparatus of the present invention. That is, it can be understood that the muscle activity amount can be measured without using data such as an MRI image by using the muscle activity amount measuring apparatus of the present invention.

Although main embodiment was described in Example 1, 2, embodiment of this invention is not limited to these. For example, in the construction of the electrical conduction simulation model in the body, the method of extracting the contour line 17 of the forearm cross section 25 and the contour line 13 of each muscle is used for the cross-sectional image used for the extraction, such as CT or MRI. It is desirable to use a forearm cross-sectional image of a person to be measured by a tomographic apparatus of a human body or a three-dimensional image capturing apparatus. When the person to be measured cannot be photographed by the device as described above, the outline is extracted from the tomographic image of another person or the tomographic image of the skeleton, and the outline is enlarged or reduced in accordance with the forearm dimension of the person to be measured. It may be used.

When the muscle block region surrounded by the outline 13 of the muscle cross section is divided into the virtual muscle fibers 14, the width and height of the cross section of the virtual muscle fibers 14 are 0.1 mm and the average diameter of the muscle fibers. Although 20 micrometers etc. can be considered, any may be sufficient if a cross-sectional shape is fully reproducible with a virtual muscle fiber. In the forearm, the virtual muscle fiber division size is desirably 0.2 mm or less as a size that can sufficiently reproduce the cross-sectional shape. The cross-sectional shape may be a triangular cross-section, a square cross-section, a hexagonal cross-section, etc., and any of them may be used. Of the square cross-sections, a square cross-section is desirable because it can be easily divided and calculated.

In the first and second embodiments, the bipolar electrode is disposed in the measurement of the surface myoelectric potential of the body. However, in addition to the bipolar electrode, an electrode array including a large number of small electrodes may be disposed.

In the second embodiment, an example in which two types of bipolar electrodes having a narrow interval and a wide interval are arranged on the forearm has been described, but the electrode interval of the bipolar electrode is further increased to have other types of electrode intervals such as three types and four types. If bipolar electrodes are used, more detailed muscle activity measurement can be performed.

The evaluation function f is the sum of squares of the absolute values of the difference between the simulation RMS value and the measured surface myoelectric potential RMS value, but this may be the sum of the cubes of the absolute values, the sum of the fourths, or the sum of the absolute values. The absolute value may be the sum of positive real powers. Alternatively, the evaluation function f may be the sum of the absolute values of the difference between the simulation MS value and the measured surface myoelectric potential MS value, the sum of the squares of the absolute values, the sum of the third power, the sum of the fourth power, or the sum of the positive real powers. Further, functions other than those shown here may be added to the evaluation function.

In the first and second embodiments, the embodiment of the present invention in the forearm has been described. For example, it can be applied to parts such as the upper arm, thigh, lower leg, and neck. When the present invention is carried out at these sites, the portion indicated as the forearm is read as the upper arm, thigh, lower leg, and neck in the embodiments and examples for carrying out the invention described above.

The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

The present invention can be used in the manufacturing industry of myoelectric potential measuring devices.

11 Surface electrode 12 on simulation model No. i virtual surface electrode 13-1 Outline of muscle block region 13 Muscle block region 14 No. k virtual muscle fiber 15 in muscle j Muscle j divided into virtual muscle fibers Outline line 16 of electrode-virtual muscle fiber 17 Outline line of forearm cross section 21 Forearm 22 Surface electrode 22a Each electrode 22b constituting a bipolar electrode with a narrow electrode interval Each electrode 23 constituting a bipolar electrode with a wide electrode interval Electrode cable 23a Electrode cable 23b connected to each electrode constituting a bipolar electrode having a narrow electrode interval Electrode cable 24 connected to each electrode constituting a bipolar electrode having a wide electrode interval Surface myoelectric potential measuring section 25 Forearm cross-sectional line 26 Forearm center line

Claims (5)

A surface electrode arranged in a ring around the approximately cylindrical part of the body,
A muscle activity measuring device having a surface myoelectric potential measuring unit for measuring a surface myoelectric potential in the surface electrode,
A surface myoelectric potential simulation unit for calculating a surface myoelectric potential simulation value at the position of the surface electrode from a muscle activity amount of a muscle in a cross section at a position where the surface electrodes of the substantially cylindrical portion of the body are arranged in an annular shape;
The surface myoelectric potential simulation value at the position of the surface electrode calculated by the surface myoelectric potential simulation unit and the surface myoelectric potential at the position of the surface electrode measured by the surface myoelectric potential measurement unit are roughly matched. A muscle activity amount estimation unit that adjusts the amount of muscle activity in the cross section and estimates the muscle activity amount when roughly matching the muscle activity amount in the body;
Comprising
The calculation of the surface myoelectric potential simulation value at the position of the surface electrode in the surface myoelectric potential simulation unit is as follows:
(A) A muscle block region obtained by finely dividing a circular cross section of a substantially cylindrical portion of the body into 5 mm or less by finite element division, and (b) Finely less than ½ of the width of the muscle block region constituting the muscle block region. Assuming split virtual muscle fibers,
The time square average value of the surface myoelectric potential due to the muscle activity of the virtual muscle fiber is calculated from the time square mean value of the muscle activity amount of the virtual muscle fiber, and the virtual muscle is calculated for the muscle block region in the transverse section. A muscle activity amount measuring apparatus for calculating the surface myoelectric potential simulation value by taking a square root of a sum of time square mean values of surface myoelectric potentials based on fiber muscle activity amount. The muscle activity amount estimation unit calculates a muscle activity amount of a virtual muscle fiber in the transverse section when a surface myoelectric potential simulation value at the position of the surface electrode and a surface myoelectric potential at the position of the surface electrode approximately coincide with each other. The muscle activity amount measuring apparatus according to claim 1, wherein the muscle activity amount is estimated as a muscle activity amount of a virtual muscle fiber in the inside. The muscle activity amount estimation unit calculates the surface myoelectric potential simulation value by adjusting the muscle activity amount of virtual muscle fibers belonging to the same muscle block region when adjusting the muscle activity amount of the virtual muscle fiber. Item 3. A muscle activity measuring apparatus according to Item 2. The muscle activity amount measuring apparatus according to any one of claims 1 to 3, wherein the muscle block region has a fine size near the outer periphery of the cross section and increases toward the approximate center. The surface electrode is a bipolar electrode in which two electrodes are paired, and two or more bipolar electrodes having different intervals between the two electrodes are arranged so that the midpoint of a line segment connecting the central portions of the two electrodes is The muscle activity measuring device according to any one of claims 1 to 4, wherein the muscle activity amount measuring device is arranged so as to be approximately coincident.

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