Co-contraction control device, co-contraction control method, server device, distribution method, and program

Abstract

A co-contraction control device according to an embodiment comprises: an agonist muscle determination unit that determines an agonist muscle of a subject on the basis of time series data of the subject's body movement and a threshold value; a co-contraction determination unit that determines, on the basis of time series data of the subject's muscle activity and a threshold value, whether or not co-contraction is occurring between the agonist muscle determined by the agonist muscle determination unit and an antagonist muscle of the subject; and an output unit that outputs, when the co-contraction determination unit determines that the co-contraction is occurring, a control signal for electrical stimulation to the agonist muscle determined by the agonist muscle determination unit for suppressing the co-contraction.

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a co-contraction control device, a co-contraction control method, a server device, a distribution method, and a program. [Background technology]

[0002] For humans to perform smooth joint movement, it is important to properly contract and relax the agonist and antagonist muscles. The agonist muscle is primarily responsible for contracting to achieve the desired movement. The antagonist muscle is located on the opposite side of the agonist muscle and assists in efficient movement by relaxing simultaneously with the contraction of the agonist muscle.

[0003] However, in actual exercise, there are times when the antagonist muscle contracts at the same time as the agonist muscle, i.e., co-contraction occurs, which interferes with the joint movement of the agonist muscle. Electrical Muscle Stimulation (EMS) is used as a technique to suppress this co-contraction.

[0004] For example, Non-Patent Document 1 discloses that the presentation (supply) of EMS to the tibialis anterior muscle (TA), which is the agonist muscle of a subject, enhances the stretching effect of the triceps surae, which is its antagonist muscle, i.e., the co-contraction inhibitory effect, in a short period of time.

[0005] Furthermore, for example, Non-Patent Document 2 discloses that a spinal reflex mechanism that inhibits antagonistic muscles functions even when a subject is in a state of voluntary co-contraction. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] SHUNMEI TERUI, et al. Simultaneous Execution of Neuromuscular Electrical Stimulation (NMES) and Muscle Stretching Increases Muscle Extensibility in a Short Time. Journal of Physical Therapy Science, 2016, 31.1: 87-91. [Non-patent document 2] HIRABAYASHI, Ryo, et al. Effects of reciprocal Ia inhibition on contraction intensity of co-contraction. Frontiers in human neuroscience, 2019, 12: 527. Summary of the Invention [Problem to be solved by the invention]

[0007] The techniques disclosed in the above-mentioned Non-Patent Documents 1 and 2 are targeted at simple joint movements in which the agonist and antagonist muscles are known in advance, and EMS is applied to the agonist muscles in a steady state. However, in complex exercises, such as balance exercises, in order to suppress co-contraction and achieve smooth movements, the following problems (1) and (2) that are not taken into account in the above-mentioned techniques can be considered.

[0008] (1) As agonist and antagonist muscles change from moment to moment during exercise, it is necessary to apply EMS to the appropriate muscles that should be designated as agonists. (2) EMS must be presented at the appropriate timing to cause co-contraction.

[0009] The present invention has been made in light of the above-mentioned circumstances, and an object of the present invention is to provide a co-contraction control device, a co-contraction control method, a server device, a distribution method, and a program that are capable of suppressing co-contraction and achieving smooth operation. [Means for solving the problem]

[0010] A co-contraction control device according to one aspect of the present invention includes an agonist determination unit that determines a agonist muscle of a test subject based on time-series data of the subject's physical movement and a threshold value; a co-contraction determination unit that determines whether co-contraction is occurring between the agonist muscle determined by the agonist determination unit and an antagonist muscle of the test subject based on time-series data of the subject's muscle activity and a threshold value; and an output unit that, when the co-contraction determination unit determines that co-contraction is occurring, outputs a control signal for electrical stimulation of the agonist muscle determined by the agonist determination unit in order to suppress the co-contraction.

[0011] A co-contraction control method according to one embodiment of the present invention is a method performed by a co-contraction control device, in which an agonist determination unit of the co-contraction control device determines the agonist muscle of the test subject based on time-series data of the body movement of the test subject and a threshold value, a co-contraction determination unit of the co-contraction control device determines whether co-contraction is occurring between the agonist muscle determined by the agonist determination unit and an antagonist muscle of the test subject based on time-series data of muscle activity of the test subject and a threshold value, and an output unit of the co-contraction control device outputs a control signal for electrical stimulation to the agonist muscle determined by the agonist determination unit in order to suppress the co-contraction when the co-contraction determination unit determines that co-contraction is occurring. [Effects of the Invention]

[0012] According to the present invention, co-contraction can be suppressed to achieve smooth operation. [Brief explanation of the drawings]

[0013] [Figure 1]FIG. 1 is a diagram showing an example of application of a co-contraction control system according to one embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of the functional configuration of a co-contraction control system according to one embodiment of the present invention. [Figure 3] FIG. 3 is a flowchart showing an example of a procedure of processing operations of a co-contraction control system according to one embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram showing an example of the hardware configuration of a co-contraction control device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described below with reference to the drawings. The technology described in one embodiment of the present invention is a technology for suppressing co-contraction that has two functions: a function to sequentially determine the prime mover muscles that should be activated to stabilize the posture of the subject, based on the joint movements of the subject during movement, and to which EMS should be presented when co-contraction occurs; and a function to determine the occurrence of co-contraction based on muscle activity during the subject's movement, and to present EMS to suppress this co-contraction when co-contraction occurs.

[0015] In this embodiment, ankle joint control during a standing balance task is used as an example of actual movement. This task requires complex control of the ankle joint to stabilize posture, i.e., to suppress postural sway, and this co-contraction of the ankle joint is considered to be the main cause of increased postural sway. Here, the subject is a task in which the subject stands on one right leg on a balance board that tilts only forward and backward.

[0016] FIG. 1 is a diagram showing an application example of a co-contraction control system according to an embodiment of the present invention. In the example shown in FIG. 1 , the co-contraction control system 100 includes a motion capture system 10, an electromyograph 20, a co-contraction control device 30, a microcomputer 40, an electrical stimulator (electrical muscle stimulator) 50, and a distribution server 60.

[0017] As a preliminary preparation for operation using the co-contraction control system, a motion capture measurement marker (sometimes simply referred to as a marker) (not shown) is attached to the front end of a balance board (not shown) possessed by the motion capture system 10, and this balance board is connected to the co-contraction control device 30. The motion capture system 10 measures the three-dimensional position coordinates of the marker.

[0018] As a preliminary preparation, an electromyograph 20 is attached to the tibialis anterior and soleus (SOLEUS) muscles of the ankle joint of the subject, and the electromyograph 20 is connected to the co-contraction control device 30.

[0019] The electromyograph 20 measures the muscle activity of each muscle of the subject by electromyography (EMG). In addition, electrical stimulation electrodes (not shown) are attached to the subject's muscles and connected to the electrical muscle stimulation device 50. The electrical muscle stimulation device 50 is connected to the co-contraction control device 30 via the microcomputer 40.

[0020] The electrical muscle stimulator 50 can apply EMS to each muscle of the subject to contract the muscle. The motion capture system 10 and electromyograph 20 operate in synchronization. The co-contraction control system 100 applies EMS to the subject's tibialis anterior or soleus muscle according to the center of gravity sway parameter and EMG measurement results. Here, the fluctuation in the height (h) of the front end of the balance board is used as the center of gravity sway parameter.

[0021] FIG. 2 is a block diagram showing an example of the functional configuration of a co-contraction control system according to one embodiment of the present invention. As shown in FIG. 2 , the co-contraction control system 100 can be realized by various functions including a body movement evaluation unit 11 in the motion capture system 10, an electromyography evaluation unit 21 in the electromyography 20, a time-series data storage unit 31 in the co-contraction control device 30, a master agonist threshold determination unit 32, a master agonist determination unit 33, a co-contraction threshold determination unit 34, and a co-contraction determination unit 35, and an electrical stimulation presentation unit 51 in the electrical stimulation device 50.

[0022] FIG. 3 is a flowchart showing an example of a procedure of processing operations of a co-contraction control system according to an embodiment of the present invention. Body Movement Evaluation Section 11 The body movement evaluation unit 11 measures the position of the target body part of the subject at time t and transmits this measurement result as time-series data of the subject's current body movement to the co-contraction control device 30. In this embodiment, the height h of the front end of the balance board due to the current body movement of the subject using the balance board is measured by the motion capture system 10, and the position of the target body part is measured based on this measurement result.

[0023] Myoelectric Evaluation Unit 21 The myoelectricity evaluation unit 21 measures the muscle activity of each muscle of the subject at time t using EMG, and transmits the measurement results to the co-contraction control device 30 as time-series data of the subject's current muscle activity.

[0024] Time series data storage unit 31 The subject himself performs a movement task similar to the current one in advance, and time series data of the body movement in the pre-experiment (pre-task) and time series data of the muscle activity of the target muscle by EMG in the pre-experiment are collected and stored in the time series data storage unit 31 (S1, S2). For example, in this embodiment, the subject himself / herself performs a balance task similar to the current one in advance, and (1) time series data of body movement, i.e., time series data ht of the height h of the front end of the balance board, and (2) time series data Et of muscle activity of each muscle by EMG can be collected.

[0025] ·Movement muscle threshold determination unit 32 The agonist threshold determination unit 32 receives time-series data of the body movement in the pre-task and outputs a threshold to the agonist determination unit 33 using a predetermined formula according to the type of task to determine the appropriate agonist muscle, i.e., the agonist muscle that should be activated to stabilize the subject's posture and to which EMS should be presented when co-contraction occurs. For example, the master muscle threshold determination unit 32 receives input of time-series data of the body movement in the pre-task, and outputs thresholds h_ta and h_so to the master muscle determination unit 33 to determine the appropriate master muscle to which EMS should be applied in order to stabilize the posture in the body movement.

[0026] In this embodiment, when the height h of the front end of the balance board indicated by the time-series data of the subject's current body movement is equal to or less than the threshold value h_ta, the subject's tibialis anterior muscle is determined to be the appropriate prime mover by the prime mover determination unit 33 described below. Also, when the height h of the front end of the balance board indicated by the time-series data of the subject's current body movement is equal to or greater than the threshold value h_so, the subject's soleus muscle is determined to be the appropriate prime mover by the prime mover determination unit 33 described below.

[0027] If the mean value of the time series data of the height h of the front end of the balance board is h_mean and the standard deviation of the time series data is h_std, the following equations (1) and (2) are defined. h_ta = h_mean - h_std …Equation (1) h_so = h_mean + h_std …Equation (2)

[0028] Here, with regard to the height h of the front end of the balance board indicated by the time series data of the subject's current physical movement, in the region of "h_ta < h < h_so", that is, the region as described above where it is neither below the threshold h_ta nor above the threshold h_so, the subject is able to maintain a relatively level balance, and therefore the height h of the front end of the balance board can be called the "stable region".

[0029] Furthermore, with regard to the height h of the front end of the balance board indicated by the time series data of the current body movement, in areas other than the above "h_ta < h < h_so", i.e., areas below the above threshold h_ta or above the threshold h_so, the balance board is tilted significantly, so the height h of the front end of the balance board can be called an "unstable area".

[0030] ·Major action muscle determination unit 33 The activator muscle determination unit 33 receives the time-series data of the subject's current body movement transmitted from the body movement evaluation unit 11, and determines an appropriate activator muscle according to the subject's body movement at time t based on this time-series data and the threshold output from the activator muscle threshold determination unit 32. In this embodiment, the activator muscle determination unit 33 determines whether the appropriate activator muscle should be the tibialis anterior (TA) or the soleus (SO) (S3).

[0031] Co-contraction threshold determination unit 34 The co-contraction threshold determination unit 34 receives input of time-series data of the subject's muscle activity measured by EMG in a preliminary experiment and outputs a threshold for determining whether the time-series data of the subject's current muscle activity measured by EMG is in a co-contraction state. In this embodiment, when the value of muscle activity of the antagonist muscle exceeds the threshold Eth, it can be determined that the time-series data of the subject's current muscle activity measured by EMG is in a co-contraction state.

[0032] Furthermore, if the mean value of the time series data of the subject's muscle activity measured by EMG when the height of the front end of the balance board is in the stable region (h_ta < h < h_so) among the time series data of physical movements in the preliminary experiment is defined as E_mean, and the standard deviation of the time series data of the subject's muscle activity measured by EMG when the height of the front end of the balance board is in the stable region is defined as E_std, then the following equation (3) is defined. Eth = E_mean + E_std…Equation (3)

[0033] Co-contraction determination unit 35 The co-contraction determination unit 35 receives the time series data of the subject's current muscle activity transmitted from the myoelectric evaluation unit 21 via the agonist determination unit 33, and determines whether the subject's current muscle activity at time t is in a co-contraction state, i.e., whether the subject's agonist and antagonist muscles are co-contracting, based on this time series data and the threshold value Eth output from the co-contraction threshold determination unit 34 (S4).

[0034] When the above muscle activity is in a co-contraction state, i.e., when it is determined that the muscle activity value of the subject's antagonist muscle exceeds the threshold Eth (Yes in S4), it is considered necessary to suppress the action (contraction) of the subject's antagonist muscle in order to suppress co-contraction, so the co-contraction determination unit 35 sends a trigger signal, which is a control signal for presenting EMS to the determined appropriate agonist muscle, to the microcontroller 40. On the other hand, when the muscle activity is not in a co-contraction state, that is, when it is determined that the muscle activity value of the subject's antagonist muscle is equal to or less than the threshold value Eth (No in S4), the subject is considered to be able to control his / her posture by himself / herself, and therefore the co-contraction determination unit 35 does not send the trigger signal (S6).

[0035] Electrical stimulation presentation unit 51 When microcomputer 40 receives the trigger signal transmitted from co-contraction determination unit 35, electrical stimulation presentation unit 51 of electrical stimulation device 50 receives and recognizes this signal from microcomputer 40, and presents EMS to the determined appropriate agonist muscles of the subject for Δt seconds (S5). This suppresses co-contraction occurring in the subject.

[0036] Next, variations according to this embodiment will be described in the following (1) to (7). (1) The time-series data of body movements and muscle activity in the preliminary experiment may be data from balance tasks of others, such as skilled exercisers. For example, the threshold may be determined based on the movements of a physical therapist, and EMS may be presented as a stimulus to a paralyzed patient. Alternatively, the threshold may be determined based on the movements of a professional player or coach, and applied to the trainee.

[0037] (2) The subject's movement may be driven not by human muscles but by a mechanical power source such as artificial muscles, and the thresholds for muscle activity and physical movement may be determined based on time-series data of human physical movement, and a signal that serves as an alternative to electrical stimulation may be input to the artificial muscles.

[0038] (3) As examples of actual movements, in addition to the standing balance task mentioned above, this method can also be applied to other movements that require switching between agonist and antagonist muscles, such as walking or periodic arm swing motion, and the target muscles can also be changed depending on the movement task.

[0039] (4) The time series data of the body movements in the preliminary experiment and the time series data of the muscle activity of the target muscles by EMG in the preliminary experiment, which are stored in the time series data storage unit 31, may be stored in advance in a storage device (not shown) within the distribution server 60. In this case, if necessary, in order to determine the various thresholds, the agonist muscle threshold determination unit 32 or the co-contraction threshold determination unit 34 of the co-contraction control device 30 requests the distribution server 60 to distribute (acquire) the time-series data, i.e., makes a download request, via the communication network. In response to this distribution request, the distribution unit (not shown) of the distribution server 60 can distribute the stored time-series data via the communication network to the co-contraction control device 30, which is the source of the distribution request.

[0040] (5) The various thresholds determined by the agonist muscle threshold determining unit 32 or the co-contraction threshold determining unit 34 may be stored in advance as threshold data in a storage device (not shown) in the distribution server 60. In this case, if necessary, the master muscle determination unit 33 or the co-contraction determination unit 35 of the co-contraction control device 30 requests the distribution server 60 to distribute the threshold data, i.e., request a download, via the communication network, and the distribution unit of the distribution server 60 can distribute the stored threshold data to the co-contraction control device 30, which is the source of the distribution request, via the communication network in response to this distribution request.

[0041] (6) The formula for determining the threshold determined by the agonist muscle threshold determination unit 32 is not limited to the single formula shown in the formulas (1) and (2) above, but may be configured so that the user can arbitrarily select from multiple types of thresholds, for example, a formula for professionals and a formula for amateurs. The formula for professionals is, for example, a formula including relatively complex parameters that professionals can handle, while the formula for amateurs is, for example, a formula including relatively simple parameters that amateurs can handle.

[0042] (7) The formula for determining the threshold value determined by the co-contraction threshold determination unit 34 is not limited to the single formula shown in the formula (3) above, but may be configured so that the user can select any of a plurality of types of threshold values, for example, formulas for professional use and formulas for amateur use.

[0043] In one embodiment of the present invention as described above, the agonist muscle to which EMS should be applied when co-contraction occurs in the test subject is sequentially determined, and EMS is applied to the agonist muscle at the appropriate timing when co-contraction occurs, thereby suppressing co-contraction and achieving smooth movement even in complex physical movements such as balance exercises.

[0044] In the example of the standing balance task mentioned above, by sequentially determining the primary muscles that should be activated to stabilize the subject's posture and presenting EMS to these primary muscles at the timing when co-contraction occurs, efficient ankle joint movement can be achieved, which is thought to contribute to postural stability, such as reducing center of gravity sway.

[0045] FIG. 4 is a block diagram showing an example of the hardware configuration of a co-contraction control device according to one embodiment of the present invention. 4, the co-contraction control device 30 according to the embodiment described above is configured, for example, by a server computer or a personal computer, and includes a hardware processor 311A ​​such as a CPU (Central Processing Unit). A program memory 311B, a data memory 312, an input / output interface 313, and a communication interface 314 are connected to the hardware processor 311A ​​via a bus 315. The same is true for the microcomputer 40, the electrical stimulation device 50, and the distribution server 60 shown in FIG. 1, and the distribution server 60 may be configured by the server computer described above.

[0046] The communication interface 314 includes, for example, one or more wireless communication interface units, and enables transmission and reception of information to and from a communication network NW. As the wireless interface, for example, an interface that adopts a low-power wireless data communication standard such as a wireless LAN (Local Area Network) is used.

[0047] The input / output interface 313 is connected to the motion capture system 10 and electromyograph 20 shown in FIG. 1, as well as other input and output devices (not shown). The input / output interface 313 can take in operation data input by a user or the like through an input device such as a keyboard, a touch panel, a touchpad, or a mouse, and can perform processing to output and display output data to an output device including a display device using liquid crystal or organic EL (Electro Luminescence), etc. Note that the input and output devices may be devices built into the co-contraction control device 30, or may be input and output devices of other information terminals that can communicate with the co-contraction control device 30 via the network NW.

[0048] The program memory 311B is a non-transitory tangible storage medium that is a combination of a non-volatile memory that can be written to and read from at any time, such as a hard disk drive (HDD) or a solid state drive (SSD), and a non-volatile memory such as a read only memory (ROM), and stores programs necessary to execute various control processes, etc., according to one embodiment.

[0049] The data memory 312 is a tangible storage medium that is, for example, a combination of the above-mentioned nonvolatile memory and a volatile memory such as RAM (Random Access Memory), and is used to store various data acquired and created during various processing steps.

[0050] A co-contraction control device 30 according to one embodiment of the present invention can be configured as a data processing device having, as software processing functional units, agonist muscle threshold determination unit 32, agonist muscle determination unit 33, co-contraction threshold determination unit 34, and co-contraction determination unit 35 shown in FIG. 2.

[0051] The information storage units and time-series data storage unit 31 used as working memories by the units of the co-contraction control device 30 can be configured using the data memory 312 shown in Fig. 4. However, these configured storage areas are not essential components within the co-contraction control device 30, and may be areas provided in an external storage medium such as a USB (Universal Serial Bus) memory, or in a storage device such as a database server located in the cloud.

[0052] Any of the above processing function units can be realized by having the hardware processor 311A ​​read and execute a program stored in the program memory 311B. Note that some or all of these processing function units may be realized in various other forms, including integrated circuits such as an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA).

[0053] The methods described in each embodiment may be stored as a program (software means) that can be executed by a computer on a recording medium such as a magnetic disk (e.g., a floppy disk, a hard disk, etc.), an optical disk (e.g., a CD-ROM, a DVD, an MO, etc.), or a semiconductor memory (e.g., a ROM, a RAM, a flash memory, etc.), or may be transmitted and distributed via a communication medium. The program stored on the medium also includes a configuration program that configures the software means (including not only execution programs but also tables and data structures) that the computer executes. The computer that realizes this device reads the program stored on the recording medium and, in some cases, configures the software means using the configuration program, and executes the above-described processing by having the operation controlled by this software means. The term "recording medium" as used herein is not limited to a storage medium for distribution, but also includes a storage medium such as a magnetic disk or semiconductor memory installed inside the computer or in a device connected via a network.

[0054] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0055] 100... Co-contraction control system 10. Motion capture system 11...Body movement evaluation section 20...Electromyograph 21...Electromyography evaluation section 30... Co-contraction control device 31...Time series data storage section 32...Movement muscle threshold determination unit 33…Main action muscle determination section 34... Co-contraction threshold determination unit 35... Co-contraction judgment section 40...Microcomputer (MCU) 50...Electrical stimulation device (electrical muscle stimulation device) 51...electrical stimulation presentation unit 60...Distribution server

Claims

1. a main activator muscle determination unit that determines a main activator muscle of the test subject based on time-series data of the body movement of the test subject and a threshold value; a co-contraction determination unit that determines whether or not co-contraction occurs between the agonist muscle determined by the agonist muscle determination unit and an antagonist muscle of the test subject, based on the time-series data of muscle activity of the test subject and a threshold value; an output unit that outputs, when the co-contraction determination unit determines that the co-contraction is occurring, a control signal for electrical stimulation to the agonist muscle determined by the agonist muscle determination unit in order to suppress the co-contraction; A co-contraction control device comprising:

2. The time-series data of muscle activity is data that can be acquired from a server device via a communication network. The co-contraction control device of claim 1 .

3. The co-contraction determination unit determining whether or not co-contraction between the agonist muscle determined by the agonist muscle determination unit and the antagonist muscle of the subject is occurring based on time-series data of muscle activity related to the movement of the ankle joint in the standing balance task of the subject and a threshold value; The co-contraction control device of claim 1 .

4. a storage device in which time-series data of muscle activity of the subject is stored in advance; a distribution unit that distributes the time-series data of the muscle activity of the test subject stored in the storage device to the co-contraction control device via a communication network in accordance with a distribution request from the co-contraction control device according to claim 1; A server device comprising:

5. 1. A method performed by a co-contraction control device, comprising: determining a movant muscle of the test subject based on time-series data of the body movement of the test subject and a threshold value by a movant muscle determination unit of the co-contraction control device; a co-contraction determination unit of the co-contraction control device determines whether or not co-contraction is occurring between the agonist muscle determined by the agonist muscle determination unit and the antagonist muscle of the test subject, based on the time-series data of muscle activity of the test subject and a threshold value; an output unit of the co-contraction control device outputs a control signal for electrical stimulation to the agonist muscle determined by the agonist muscle determination unit to suppress the co-contraction when the co-contraction determination unit determines that the co-contraction is occurring; Co-contraction control method.

6. A method performed by a server device having a storage device in which time-series data of muscle activity of the subject is stored in advance, a distribution unit of the server device distributing the time-series data of muscle activity of the test subject stored in the storage device to the co-contraction control device via a communication network in accordance with a distribution request from the co-contraction control device according to any one of claims 1 to 3; Delivery method.

7. A program that causes a processor to function as each unit of the co-contraction control device according to any one of claims 1 to 3 or as a distribution unit of the server device according to claim 4.

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