Electric stimulator and electric stimulation method

Abstract

To provide an electric stimulator and an electric stimulation method for training that suppresses uncomfortable stimulation when applying electric stimulation to a user's muscle. and applies stimulation to a muscle with higher output.SOLUTION: An electric stimulator for applying electric stimulation to a user's muscle includes: one or two or more electrode pairs stuck to a skin surface of the user; and voltage application means for applying a voltage to the electrode pairs and outputting an electric signal of a frequency equal to or lower than 100 Hz. The waveform of the voltage applied by the voltage application means is a rectangular wave in which the value of the voltage gradually increases discretely.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an electrical stimulation device and an electrical stimulation method for electrically stimulating the muscles of a user. [Background technology]

[0002] Electrical stimulation (bio-stimulation) is a method of inducing muscle contraction by attaching electrodes to a living body (user) and using electrical stimulation (EMS) technology. In other words, electrical stimulation is applied to muscles via electrodes, which can stimulate muscle contraction (tension and relaxation). Electrical stimulation is used in a variety of fields, including training, rehabilitation, relaxation, weight loss, and beauty.

[0003] For example, Patent Document 1 describes an electrical stimulation device (muscle training device) that electrically stimulates muscles, using a sine wave signal of a medium frequency (1 kHz to 5 kHz). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-175166 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, in order to stimulate deeper muscles, the frequency is increased (1 kHz or higher) to allow the electrical signal to penetrate more easily into the living body. On the other hand, it is known that with electrical stimulation using medium frequencies as described in Patent Document 1, the user experiences a sensation similar to paralysis during use, and this sensation can persist even after use, which can interfere with the user's continued use.

[0006] Furthermore, when using low-frequency electrical signals of 100 Hz or less, the occurrence of a paralysis-like sensation during use can be suppressed, but the electrical signal flows easily through the surface layer of the skin due to skin resistance, and the output of the electrical signal (applied voltage) must be increased to adequately stimulate the muscles. However, it is known that an increase in the output of the electrical signal can cause discomfort such as pain, and when using electrical stimulation for training, it becomes difficult to ensure the output required to adequately stimulate the muscles during continuous use by the user.

[0007] Therefore, an object of the present invention is to provide an electrical stimulation device and an electrical stimulation method for training that suppresses unpleasant stimulation when electrically stimulating the user's muscles and makes it possible to stimulate the muscles with a higher output. [Means for solving the problem]

[0008] As a result of intensive research into the above-mentioned problems, the inventors have found that when applying electrical stimulation to the user's muscles using low frequencies, the electrical signal transmitted from the electrodes attached to the user's skin surface flows to the skin only for the moment the applied signal is output, and then suddenly drops due to skin resistance, resulting in a spike-like waveform, which is the cause of discomfort. Therefore, the inventors have found that by using a stepped rectangular wave that rises in stages rather than a monotonous rectangular wave as the voltage waveform for applying electrical stimulation, it is possible to prevent the electrical signal from momentarily stimulating the skin or muscles at the time of output, and to increase the output without causing discomfort to the user, thereby completing the present invention. That is, the present invention provides an electrical stimulation device and an electrical stimulation method for the following training.

[0009] In order to solve the above problem, one embodiment of the electrical stimulation device of the present invention is an electrical stimulation device that electrically stimulates the muscles of a user, and is equipped with one or more electrode pairs that are attached to the surface of the user's skin, and a voltage application means that applies a voltage to the electrode pairs and outputs an electrical signal with a frequency of 100 Hz or less, and is characterized in that the waveform of the voltage applied by the voltage application means is a rectangular wave in which the voltage value increases discretely.

[0010] When a simple square wave voltage waveform is applied to output a low frequency electrical stimulus of 100 Hz or less via electrodes attached to the user's skin, a sensation similar to paralysis does not occur, but the electrical signal from the electrodes flows to the skin only for the moment it is output, and then drops rapidly due to skin resistance, resulting in an electrical stimulus in the form of a spike-like waveform.In other words, a strong instantaneous stimulus is applied to the skin and muscles, leading to an unpleasant sensation similar to pain. The electrical stimulation device of the present invention can output low-frequency electrical signals and use a square wave with a discretely increasing voltage, thereby making it possible to suppress stimulation at the moment of output and transmit a stable electrical signal to the muscles while taking advantage of the benefits of using low frequencies. This suppresses unpleasant stimulation when electrically stimulating the user's muscles and enables stimulation of the muscles with a higher output.

[0011] In one embodiment of the electrical stimulation device of the present invention, the voltage waveform is a rectangular wave whose value increases discretely in two or three stages. According to this feature, the voltage waveform increases discretely, particularly in two or three stages, which more effectively suppresses unpleasant stimuli and allows the user to experience a sufficient muscle contraction effect, thereby encouraging continued use by the user.

[0012] In one embodiment of the electrical stimulation device of the present invention, the multiplication factor of the voltage value is an integer multiple. This feature makes it easier to control the voltage application, enabling stable voltage application, which reduces unpleasant irritation and encourages users to continue using the device.

[0013] The electrical stimulation method of the present invention for solving the above problems is an electrical stimulation method for providing electrical stimulation to a user's muscles, and comprises an electrode pair arrangement step of attaching one or more electrode pairs to the user's skin surface, and a voltage application step of applying a voltage to the electrode pair to output an electrical signal with a frequency of 100 Hz or less, characterized in that the waveform of the voltage applied in the voltage application step is a rectangular wave in which the voltage value increases discretely. The electrical stimulation method of the present invention can output a low-frequency electrical signal and use a rectangular wave whose voltage increases stepwise, thereby making it possible to suppress stimulation at the moment of output and transmit a stable electrical signal to the muscles while taking advantage of the benefits of using low frequencies. This suppresses unpleasant stimulation when electrically stimulating the user's muscles and enables stimulation of the muscles with a higher output. [Effects of the Invention]

[0014] According to the present invention, an electrical stimulation device and an electrical stimulation method can be provided that suppress unpleasant stimulation when electrically stimulating the user's muscles and enable stimulation of the muscles with higher output. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram illustrating an electrical stimulation device according to an embodiment of the present invention in use. [Figure 2] FIG. 2 is a functional block diagram of a control unit of an electrical stimulation device according to an embodiment of the present invention. [Figure 3] FIG. 1 is a schematic diagram of a method for measuring the output from an EMS machine and the output through the human body using an electrical stimulation device according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram of a single-stage pulse waveform of an electrical stimulation device according to an embodiment of the present invention. FIG. [Figure 5]FIG. 2 is a schematic diagram of a two-stage pulse waveform of an electrical stimulation device according to an embodiment of the present invention. [Figure 6] 1 is a schematic diagram of a three-stage pulse waveform of an electrical stimulation device according to an embodiment of the present invention. FIG. [Figure 7] FIG. 1 is a schematic diagram illustrating the operation of a single-stage pulse of an electrical stimulation device according to an embodiment of the present invention. [Figure 8] FIG. 1 is a schematic diagram illustrating the operation of a two-stage pulse of an electrical stimulation device according to an embodiment of the present invention. [Figure 9] FIG. 1 is a schematic diagram illustrating the operation of a three-stage pulse of an electrical stimulation device according to an embodiment of the present invention. [Figure 10] 10 is a table illustrating the results of a sensory evaluation using an electrical stimulation device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an electrical stimulation device and an electrical stimulation method according to the present invention will be described in detail with reference to the drawings. The electrical stimulation device and electrical stimulation method described in the embodiments are merely examples used to explain the electrical stimulation device and electrical stimulation method according to the present invention, and are not limited to these. In this description, training devices, massage machines, and beauty devices that use electrical stimulation are collectively referred to as electrical stimulation devices. Training using an electrical stimulation device, massage, or treatment using a beauty device that uses electrical stimulation are collectively referred to as training. A person who uses an electrical stimulation device to train or massage, or a person who uses an electrical stimulation device to perform beauty treatment, is referred to as a user. Unless otherwise specified, the term "electrical stimulation device" does not exclude massagers or beauty devices.

[0017] [First embodiment] The electrical stimulation device 10 of the first embodiment is an EMS device for training the muscles of a user by applying electrical stimulation to the muscles. 1 is a schematic diagram of an electrical stimulation device according to an embodiment of the present invention in use, showing an example in which a user 51 is training the abdomen. The electrical stimulation device 10 of this embodiment includes an EMS device 11, EMS device terminals 11a and 11b, cables 12a and 12b, electrodes 13a and 13b, and an electrode pad 14. The EMS device 11 is a device that outputs electrical stimulation and incorporates a control unit 30 that controls the strength of the current, the time the current flows (pulse width), and the cycle (frequency) of the change in current or voltage. The EMS device 11 is provided with EMS device terminals 11a and 11b, to which one end of each of cables 12a and 12b is connected. The other end of each of cables 12a and 12b is connected to electrodes 13a and 13b. The electrodes 13a and 13b are fixedly attached to electrode pads 14 at a predetermined interval.

[0018] 1, in implementing electrical stimulation device 10, electrode pad 14 is attached to the skin of the user at the area where training is to be performed. Electrode pad 14 has a sheet-like shape and is attached to the body of user 51. One side of electrode pad 14 (the side not in contact with the body) is provided with plugs corresponding to electrodes 13a and 13b formed on the other side (the side in contact with the body), and these plugs are connected to cables 12a and 12b, respectively.

[0019] The electrodes 13a and 13b are attached so as to be in contact with the skin of the body of the user 51, and are arranged so as to be covered by the electrode pad 14. In other words, the electrodes 13a and 13b are fixed so as to be sandwiched between the user's skin and the electrode pad 14. 1 shows an example of a bi-electrode method in which two electrodes 13a and 13b of the same size sandwich and stimulate the application area when training the abdomen of a user 51. In addition to the abdomen, areas that can be trained include the shoulders, upper arms, back, waist, thighs, hips, and calves. Because the spacing between electrodes 13a and 13b must be changed depending on the size of the target area, several types of electrode pads 14 with different spacing between the two electrodes 13a and 13b and different sizes of the electrodes themselves may be used.

[0020] Electrodes 13a and 13b supply pulses from the skin of user 51 to the muscles, thereby performing training. Therefore, electrodes 13a and 13b are made of a conductive material. Electrodes 13a and 13b are formed, for example, from a conductive gel-like material. Electrode pad 14 is preferably an elastic thin plate made of a material such as silicone, which is insulating and conforms to the contours of the body surface. Electrodes 13a and 13b may also be formed by arranging a conductive adhesive layer on the surface of a thin metal plate such as aluminum or stainless steel, or a conductive rubber plate. Rubber electrodes, particularly gel-coated rubber electrodes, are adhesive, easy to apply, and cause minimal irritation to the skin. The electrodes may be non-adhesive, and may be made of, for example, a thin metal plate or a conductive rubber plate, or may be made of a conductive layer that is conductive but not adhesive. In this case where the electrodes are not adhesive, the electrodes may be fixed using a separate belt (not shown).

[0021] The EMS device 11 incorporates a control unit 30 that controls the output of electrical stimulation at a predetermined frequency, pulse width, pause width, and output value. Figure 2 is a functional block diagram of the control unit of an electrical stimulation device according to an embodiment of the present invention. The control unit 30 includes a power supply unit 31, a pulse wave generator 32, an output adjuster 33, and an application electrode selector 34. Power supply unit 31 supplies power to each component of electrical stimulation device 10. The power source is preferably, for example, an alkaline battery or a secondary battery such as a lithium ion battery or a nickel-metal hydride battery, and stabilizes the battery voltage to generate a drive voltage to be supplied to each component. The pulse wave generating unit 32 generates pulses with a predetermined frequency, pulse width, and pause width. The output adjusting unit 33 adjusts the voltage output value. When the EMS device 11 is equipped with multiple EMS device terminals 11a and 11b, the application electrode selecting unit 34 selects when electrical stimulation is to be output to one or more specific cables 12a and 12b and electrodes 13a and 13b.

[0022] 3A and 3B are schematic diagrams illustrating a method for measuring the output from an EMS device and the output through a human body using an electrical stimulation device according to an embodiment of the present invention. Fig. 3A shows the device configuration when measuring the output waveform from the EMS device 11. Fig. 3B shows the configuration of the device and the target area of a user 51 when applying electrical stimulation to the abdomen of the user 51. FIG. 3(a) shows a configuration for confirming that electrical stimulation is being output using the set frequency, pulse width, pause width, output value, and waveform in electrical stimulation device 10. The electrical stimulation set by the control unit 30 built into the EMS machine 11 is output from the EMS machine terminals 11a and 11b of the EMS machine 11 to the electrodes 13a and 13b via the cables 12a and 12b. A resistance of 100 to 1000 ohms is connected between the electrodes 13a and 13b, and the waveform therebetween is measured by an oscilloscope 21. 3(b) shows a configuration for attaching electrodes 13a and 13b to the body of user 51 to confirm that electrical stimulation is being output with the set frequency, pulse width, pause width, output value, and waveform in electrical stimulation device 10. In this case, too, the output from EMS device 11 via the body of user 51 is connected to the body of user 51 via electrodes 13a and 13b through a resistance of 100 to 1000 ohms, and the waveform between them is measured by oscilloscope 21.

[0023] Under the above configuration, the output of the electrical stimulation used for the sensory evaluation was a frequency of 50 Hz or 60 Hz, a pulse width of 100 to 300 μsec, a pause width of 100 to 300 μsec, and an output value of 10 to 60 V. The pause width refers to the time between the end of one pulse and the generation of the next pulse. If the pulse width is 1 msec or more, discomfort and pain due to the electrical stimulation increases, so it is desirable that the pulse width be 500 μsec or less. In this embodiment, the pulse width is set to 100 to 300 μsec.

[0024] When training muscles with electrical stimulation, the frequency bands of the pulses emitted from the electrical stimulation device are classified into three types: low frequency, medium frequency, and high frequency. Each frequency band has a different training effect. Muscles have the property of contracting when an electric current is passed through them and relaxing when no current is passed through them. Electrical stimulation utilizes this property to move muscles by sending electrical signals. By changing the frequency and other stimulation conditions from the electrical stimulation device, it can be used under conditions that are appropriate for the user. Low frequency refers to frequencies between 1 and 1000 Hz. Low frequency waves are large and thick, so they are resisted by the skin and cause a tingling pain. It is said that the current only penetrates a few millimeters beneath the skin, causing muscle movement only in very shallow areas. On the other hand, low frequencies between 20 Hz and 100 Hz are said to be most likely to cause muscle movement. Medium frequency refers to frequencies between 1000 and 10,000 Hz. Compared to low frequency, the waves are finer, so skin resistance is slightly reduced. Because skin resistance is reduced, electricity is passed 2 to 3 cm beneath the skin. It is said that increasing the intensity of electricity makes skin resistance stronger. Because the waves become finer and skin resistance is reduced, it is less likely to cause muscle movement. High frequency refers to frequencies of 10,000 Hz or higher. The electrical waves are very fine and there is almost no skin resistance, so it is said to cause almost no pain or tingling sensation. Because the skin resistance is low, the electrical current penetrates much deeper than with low or medium frequency waves.

[0025] In this embodiment, a frequency of 50 Hz or 60 Hz is used, but this frequency band is in the low frequency range. Generally, it is said that low frequencies of about 20 Hz to 100 Hz are most likely to induce muscle movement. At frequencies above 200 Hz, muscle contraction is not believed to occur. On the other hand, at frequencies of about 50 Hz, the electrical resistance of the skin reaches several kiloohms, which increases discomfort. Therefore, electrical stimulation in the 50 Hz to 60 Hz frequency band tends to increase discomfort as the output is increased. In this embodiment, it was shown that discomfort and pain can be effectively alleviated by discretely increasing the pulse voltage value even in the frequency band of 50 Hz to 60 Hz. If discomfort and pain can be effectively alleviated, there is more room to increase the output of electrical stimulation to increase the training effect. Although there are individual differences in pulse width, the above values were set as the range of values at which muscle contraction can be confirmed. Although there are individual differences in output value, the above values were set as the values at which muscle contraction occurs without causing pain.

[0026] The pulse waveforms will be explained in the case where a single pulse waveform, a two-step pulse waveform, and a three-step pulse waveform are applied. 4A and 4B are schematic diagrams of a single-stage pulse waveform of an electrical stimulation device according to an embodiment of the present invention. Fig. 4(a) shows the output waveform of the single-stage pulse waveform. Fig. 4(b) shows the estimated waveform of the single-stage pulse waveform transmitted through the human body. The basic shape of the pulse is that a pair of positive and negative sides forms one cycle. The positive and negative voltage values of the pulse are both equal, V1, the pulse width is equal for both the positive and negative pulses, T1, and the pulse pause width is P1.

[0027] Figure 5 is a schematic diagram of a two-stage pulse waveform of an electrical stimulation device according to an embodiment of the present invention. Figure 5(a) shows the output waveform of the two-stage pulse waveform. Figure 5(b) shows the estimated waveform of the two-stage pulse waveform transmitted through the human body. As with the single-stage pulse waveform, the positive and negative voltage values of the pulse are both equal (V1), the pulse widths are equal (T1) for both the positive and negative pulses, and the pulse pause width is P1. Figure 6 is a schematic diagram of a three-stage pulse waveform of an electrical stimulation device according to an embodiment of the present invention. Figure 6(a) shows the output waveform of the three-stage pulse waveform. Figure 5(b) shows the estimated waveform of the three-stage pulse waveform transmitted through the human body. As with the one-stage pulse waveform, the positive and negative voltage values of the pulses are both equal (V1), the pulse widths are equal (T1) for both the positive and negative pulses, and the pulse pause width is P1.

[0028] Figure 5(a) shows the waveform pattern when electrical stimulation is output using a two-stage pulse waveform. In this two-stage pulse waveform, a positive voltage V1a is applied for time T1a, followed by a positive voltage V1a + V1b = V1 for time T1b. After that, after a pause P1, a negative voltage V1a is applied for time T1a, followed by a negative voltage V1a + V1b = V1 for time T1b.

[0029] Figure 6(a) shows the waveform pattern when electrical stimulation is output using a three-stage pulse waveform. In this three-stage pulse waveform, a positive voltage V1a is applied for time T1a, followed by a positive voltage V1a + V1b for time T1b, followed by a positive voltage V1a + V1b + V1c = V1 for time T1c. After a pause P1, a negative voltage V1a is applied for time T1a, followed by a negative voltage V1a + V1b for time T1b, followed by a negative voltage V1a + V1b + V1c = V1 for time T1c.

[0030] There is a clear difference between the output waveform of a single-step pulse shown in Figure 4(a) and the estimated waveform through the human body shown in Figure 4(b). This is because the resistance of human skin is in the range of 1000 to 5000 ohms and varies depending on the part of the body, so a current of the output value, or in some cases less than the output value, is applied to the skin surface for just a moment, then spreads over a wider area and is simultaneously transmitted to the muscles. The same can be said for the estimated waveform through the human body shown in Figure 5(b) for the output waveform of the two-stage pulse shown in Figure 5(a), and the estimated waveform through the human body shown in Figure 6(b) for the output waveform of the two-stage pulse shown in Figure 6(a). With two-step and three-step pulses, unlike with one-step pulses, the voltage of the next step is applied before it has completely dropped after reaching the set value for each step, so that the pulse width remains high even at the end. However, with two-step and three-step pulses, the electrical energy (referring to the amount of power; the same applies below) is reduced compared to a one-step square wave, which is thought to lead to the physically perceived effect of a softer stimulation. The strength of the physical stimulation and the effect of electrical stimulation on muscles vary from person to person depending on factors such as the condition of the skin, the thickness of fat, the amount of muscle, etc. By using two-stage pulses and three-stage pulses, the physical stimulation can be adjusted, while the strength of the physical stimulation and the effect of electrical stimulation on muscles, which vary depending on the individual, can be flexibly adjusted by increasing or decreasing the pulse width. For example, increasing the pulse width can replenish electrical energy. Also, increasing the pulse width can further maintain the strength to maintain muscle contraction.

[0031] The effects of electrical stimulation with one-stage pulse waveform, two-stage pulse waveform, and three-stage pulse waveform on muscles will be explained using Figures 7 to 9. a1, a2, a3, a4 in Figure 7, b1, b2, b3, b4, b5, b6 in Figure 8, and c1, c2, c3, c4, c5, c6, c7, c8 in Figure 9 each represent the area of the portion indicated by the leading line, i.e., the electrical energy of the indicated portion.

[0032] Figure 7 illustrates the difference between the output waveform and the effect of a single-stage pulse on the human body. The voltage waveform on the human body lags behind the output waveform in both the rise and fall of the voltage. When the output rises, a loss of a1 occurs, and the current flows over a wide area due to the resistance of the skin, causing a voltage drop and a loss of a2. When the output becomes 0, the current that flowed through the skin flows with a delay, and the voltage gradually approaches 0, as shown by the shape of a4. In the case of a one-step pulse waveform, losses equivalent to a1 and a2 occur, and the voltage drops after the first rise. Depending on the output value, the peak voltage after the rise can reach the pain threshold, causing discomfort such as pain. The output electrical energy is dissipated over a wide area, including the epidermis, so the electrical energy transmitted to the target muscle is less than the output electrical energy. The way electrical energy is dissipated within the body is thought to differ depending on the constitution and the condition of the epidermis. This can be expressed in terms of the area of the waveform shown in Figure 7, as a4≦a1+a2.

[0033] Figure 8 illustrates the difference between the output waveform and the effect of a two-stage pulse on the human body. The voltage waveform on the human body lags behind the output waveform in both the rise and fall of the voltage, just like the one-stage pulse. As with the single-stage pulse, a loss in b1 occurs when the output rises, and the high resistance of the skin causes current to flow over a wide area, but because the voltage in the first stage is low, the losses in b1 and b2 are small.The same is true for the rise of the second stage, with small losses in b3 and b4. When the output becomes 0, the current that flows through the skin flows with a delay, but it is not as long as with a one-step pulse. Because b1, b2, b3, and b4 are each smaller than a1 and a2, b6 is also smaller than a4, and it is thought that the loss is also small accordingly. Because the voltage at the first stage rise is not large, it is unlikely to reach the pain threshold, and by the time the second stage rises, the user has become accustomed to the pain from the first stage voltage, so it is unlikely to feel uncomfortable. This allows a predetermined electrical stimulation to be delivered to the body while relieving pain. However, in the case of a two-stage pulse waveform, if the pulse width T1 is the same as that of a one-stage pulse waveform, the electrical energy is smaller than that of a one-stage pulse waveform, so the contractile force exerted on the muscle contraction is smaller. In other words, in terms of the area of the waveform portion shown in Figures 7 and 8, b5 <a3となる。

[0034] Figure 9 illustrates the difference between the output waveform and the effect of the three-stage pulse on the human body. The voltage waveform on the human body lags behind the output waveform in both the rise and fall of the voltage. As with the single-stage pulse waveform, loss occurs in c1 when the output rises, and the high resistance of the skin causes current to flow over a wide area, but because the voltage is low, loss in c1 and c2 is small. Similarly, loss in c3 and c4 during the second stage rise and c5 and c6 during the third stage rise is small. When the output becomes 0, the current that flows through the skin flows with a delay, but it is not longer than with a one-step pulse or a two-step pulse. c1, c2, c3, c4, c5, and c6 are each smaller than b1, b2, b3, and b4, and therefore the loss is also thought to be smaller. The voltage at the rise of the first stage is not as high as in the case of a two-stage pulse waveform, so it does not reach the pain threshold. The voltage is increased in stages to the rise of the second stage and the third stage, but the person becomes accustomed to the pain due to the first stage voltage and the two further stages of voltage, so it is even less likely to feel uncomfortable. This allows a predetermined electrical stimulation to be delivered to the body while relieving pain. However, in the case of a three-stage pulse waveform, if the pulse width T1 is the same as that of a one-stage pulse waveform, the electrical energy is smaller than that of a one-stage pulse waveform or a two-stage pulse waveform, and therefore the contractile force exerted on the muscle contraction is even smaller. In other words, in terms of the area of the waveform portion shown in Figures 7 to 9, c7 <b5<a3となる。

[0035] The effects of two-stage pulse waveforms and three-stage pulse waveforms reduce unpleasant stimulation (pain), while also reducing the electrical energy delivered to the muscles. Therefore, we will explain how to deliver electrical energy equivalent to that of a one-stage pulse waveform to the human body. The first method is to increase the voltage. By using a two-stage pulse waveform or a three-stage pulse waveform, the physical sensation of pain is alleviated, making it possible to increase the voltage without causing discomfort. This makes it possible to increase the amount of electrical energy to a level equal to or greater than that of a one-stage pulse waveform, making it possible to maintain muscle contraction to a certain extent. However, when using the method of increasing the voltage, stronger muscle contractions occur due to the higher voltage, and in strength training, it is necessary to adjust the voltage to maintain muscle contraction. The second method is to lengthen the pulse width. This method avoids the problem of voltage adjustment to maintain muscle contraction that accompanies increasing the voltage. The loss of electrical energy when comparing a two-stage pulse waveform or a three-stage pulse waveform with a one-stage pulse waveform can be compensated for by extending the pulse width. Increasing the pulse width also leads to a longer duration of muscle contraction, creating optimal conditions for strength training. In a one-step pulse waveform, a pulse width of 100 to 250 μsec is generally used, but it is easy to use a longer pulse width, making it possible to set it according to the individual's sensation.

[0036] 10 is a table illustrating the results of the sensory evaluation using the electrical stimulation device according to the embodiment of the present invention. The table summarizes the sensory evaluation results regarding discomfort and muscle contraction effects for each output waveform pattern of the electrical stimulation. With single-pulse waveform electrical stimulation, muscle contraction can be clearly felt, but it also results in pain. Pulse waveform electrical stimulation, which increases output in two stages, is superior in that it is gentler and less painful. Therefore, for people who are originally sensitive to electrical stimulation, it has the advantage of being safe to use because there is no unpleasant stimulation. On the other hand, people who are accustomed to conventional electrical stimulation may find it unsatisfying. It can be seen that the electrical stimulation with a pulse waveform that increases output in three stages resulted in a gentler sensation and less pain. On the other hand, in terms of dissatisfaction, it was felt to be more dissatisfying than the electrical stimulation with a two-stage pulse waveform.

[0037] It was found that the electrical stimulation was more mitigated by gradually increasing the output. This effect resulted in the subject feeling that the muscle contraction was not satisfying. This is thought to be because the overall electrical energy (amount of power) was reduced by gradually increasing the output waveform while keeping the pulse width constant. However, in muscle contraction, the contractile force is determined primarily by the voltage (current) value, so it is important to set the voltage (current) value as high as possible. Therefore, in order to output a high voltage (current) value without causing discomfort, it is necessary to output it in stages, which will have the effect of artificially lowering the pain threshold (acclimatization to pain).

[0038] In this embodiment, because electrical energy contributes to maintaining muscle contraction, the reduced electrical energy can be adjusted by increasing the pulse width, etc. By using a basic waveform that discretely increases the rise of the electrical stimulation as in this embodiment, discomfort can be reduced by suppressing the stimulation at the moment of output while transmitting a stable current through the skin to the muscles, and by increasing the output, muscle stimulation can be performed with a higher output, allowing for efficient training. Furthermore, by reducing discomfort, it is ultimately possible to set a higher voltage (current), which makes it possible to efficiently induce optimal muscle contractions without causing discomfort to the user, compared to conventional methods.

[0039] [Second embodiment] A second embodiment of the present invention is an electrical stimulation device characterized by a voltage waveform that is a square wave with a discrete increase in value in two or three stages. As shown in Figure 5, electrical stimulation with a pulse waveform that increases output in two stages is advantageous in that it is gentle and less painful. This allows the output to be increased while avoiding discomfort to the user, resulting in more effective muscle training. Furthermore, electrical stimulation with a pulse waveform that increases output in three stages results in a gentler and less painful experience. Because discomfort and pain vary from person to person, some users may find electrical stimulation with a pulse waveform that increases output in three stages more comfortable. Even users who are more sensitive to electrical stimulation can increase output and still achieve more effective muscle training.

[0040] [Third embodiment] A third embodiment of the present invention is an electrical stimulation device characterized in that the voltage value is increased by an integer multiple. The voltage value is increased by an integer multiple, which gradually promotes the user's bodily sensation threshold (acclimatization) to discomfort and pain, thereby providing a more comfortable feeling when using electrical stimulation.

[0041] [Other embodiments] Another embodiment of the present invention is an electrical stimulation method for electrically stimulating the muscles of a user, comprising an electrode pair placement step of attaching one or more electrode pairs to the surface of the user's skin, and a voltage application step of applying a voltage to the electrode pair to output an electrical signal having a frequency of 100 Hz or less, wherein the waveform of the voltage applied by the voltage application step is a rectangular wave in which the voltage value increases discretely. The explanation of this embodiment is to be replaced with the explanation of the first embodiment, and will be omitted. [Explanation of symbols]

[0042] 10...electrical stimulation device, 11...EMS machine, 11a, 11b...EMS machine terminal, 12a, 12b...cable, 13a, 13b...electrode, 14...electrode pad, 15...resistor, 21...oscilloscope, 30...control unit, 31...power supply unit, 32...pulse wave generation unit, 33...output adjustment unit, 34...application electrode selection unit

Claims

1. An electrical stimulation device that electrically stimulates the muscles of a user, One or more electrode pairs attached to the skin surface of the user; voltage application means for applying a voltage to the electrode pair to output an electrical signal having a frequency of 100 Hz or less; An electrical stimulation device, characterized in that the waveform of the voltage applied by the voltage application means is a square wave in which the value of the voltage increases discretely.

2. 2. The electrical stimulation device according to claim 1, wherein the voltage waveform is a rectangular wave whose value increases discretely in two or three stages.

3. 3. The electrical stimulation device according to claim 1, wherein the voltage value is multiplied by an integer multiple.

4. An electrical stimulation method for electrically stimulating a user's muscles, comprising: an electrode pair placement step of attaching one or more electrode pairs to the skin surface of the user; a voltage application step of applying a voltage to the electrode pair to output an electrical signal having a frequency of 100 Hz or less, An electrical stimulation method, characterized in that the waveform of the voltage applied in the voltage application step is a square wave in which the value of the voltage increases discretely.

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