Training device

Abstract

To provide a training device that enables maintaining of an anti-gravity muscle even under a microgravity environment.SOLUTION: Provided is a training device for training an anti-gravity muscle. The training device includes: load application means that gives a load to lose a balance from a posture in which a balance with the gravity is maintained on the ground; detection means that detects a posture in which a balance is lost by the load given by the load application means; and load calculation means that calculates the load given by the load application means on the basis of the posture in which the balance is lost and that has been detected by the detection means.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a training device, and more particularly to a training device suitable for training antigravity muscles. [Background technology]

[0002] In recent years, long-term stays in space have been realized at manned bases such as the International Space Station. It is known that a long-term stay in space significantly reduces human muscle strength due to changes in the gravitational environment. Currently, after returning to Earth, manned bases also use conventional training equipment to counter muscle weakness, but there is no equipment that is effective in countering the muscle weakness that occurs with the change in gravitational environment after returning to Earth, and only general strength training equipment is available. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3165933 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there has been a significant decline in the strength of antigravity muscles, which are responsible for posture control on Earth. If the strength of these antigravity muscles declines, astronauts may not be able to stand after returning to Earth from manned bases in space or during exploration of other planets, which could cause problems in their daily lives and exploration. For example, if training is simply performed that places a heavy load on the antigravity muscles, fast-twitch muscle fibers will develop. Also, since training that places a heavy load differs from the function of antigravity muscles on the ground, there are concerns about the function of antigravity muscles during gravity readaptation. In addition, for example, a device disclosed in Patent Document 1 has been proposed as a means for training antigravity muscles, but it is intended to be used under gravity and cannot be used for training in a zero-gravity environment such as outer space or in a microgravity environment.

[0005] Therefore, the present invention aims to provide a training device that can maintain antigravity muscles even in a microgravity environment, with the aim of application to long-term stays in space, including exploration of other planets. [Means for solving the problem]

[0006] The training device for solving the above problems is configured as a training device for training anti-gravity muscles, and is equipped with a load application means for applying a load so as to cause a person to lose balance from a posture balanced with gravity on the ground, a detection means for detecting the posture that has been lost due to the load applied by the load application means, and a load calculation means for controlling the load applied by the load application means based on the lost posture detected by the detection means. With this configuration, antigravity muscles can be maintained even in a microgravity environment, and when one's posture is disturbed, it becomes even more disturbed, so one can be conscious of maintaining correct posture and train the muscles to maintain a balanced posture with a sensation similar to that in a gravity environment. The load calculation means can apply a load simulating gravity by increasing the load as the degree of imbalance in the posture detected by the detection means increases. Furthermore, the load applying means applies a load in the front-rear direction of the body, thereby enabling anti-gravity muscles to be trained in a well-balanced manner. In addition, the load applying means applies a load so that a torque is applied when gravity acts on a joint that bends when balance is lost from a posture in which balance with gravity is maintained on the ground, thereby making it possible to train anti-gravity muscles in an environment closer to that on the ground. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 illustrates muscles that act as antigravity muscles. [Diagram 2] FIG. 1 is a diagram showing a person's unconscious movements to maintain a standing posture. [Diagram 3] This is a model diagram showing the movement of maintaining posture when deviating from the standing posture (NP). [Figure 4] FIG. 1 is a top view of one embodiment of a training device. [Diagram 5] FIG. 1 is a diagram showing the operation of the training device. [Figure 6] FIG. 4 is a block diagram showing a process performed by a load calculation means of the control device. [Figure 7] 1 is a conceptual diagram showing the relationship between the posture of a user and the load applied. [Figure 8] FIG. 1 shows antigravity muscles that act as primary muscles when leaning forward and backward. [Figure 9] FIG. 11 is a diagram showing an experimental operation in an evaluation test. [Figure 10] FIG. 11 is a diagram showing a comparison operation in an evaluation test. [Figure 11] FIG. 13 is a diagram showing experimental results in an evaluation test. [Figure 12] FIG. 13 is a diagram showing experimental results in an evaluation test. [Figure 13] FIG. 13 is a diagram showing experimental results in an evaluation test. [Figure 14] FIG. 13 is a diagram showing experimental results in an evaluation test.

[0008] The present invention will be described in detail below through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims, and not all of the combinations of features described in the embodiments are essential to the solution of the invention, and include configurations that are selectively adopted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The training device according to this embodiment is configured as a device suitable for training antigravity muscles. Antigravity muscles are muscles that work to maintain posture, such as standing or sitting, against the force of gravity. They do not work when you are actively moving your body, such as through exercise, but rather they work when you are unconsciously maintaining a certain posture.

[0010] FIG. 1 is a diagram showing muscles that act as antigravity muscles. As shown in Figure 1, antigravity muscles include the erector spinae, rectus abdominis, gluteus maximus, and quadriceps surae. The muscles located at the front and back of the lower legs, thighs, abdomen, chest, and neck stretch and contract with each other to maintain balance. On the ground, these antigravity muscles balance gravity, allowing us to maintain posture such as standing or sitting.

[0011] In the following explanation, the action of antigravity muscles on the ground will be explained using the standing posture as an example. The standing posture is the posture in which antigravity muscles are most active in order for humans to move and work while maintaining support, stability, and balance. There is an ideal basic posture for standing, called the "neutral position" (hereafter referred to as "NP"). NP is a posture that can efficiently support the body against gravity, and antigravity muscles work to immediately correct any posture in which the body's center of gravity deviates from NP.

[0012] For example, when standing, the activity of all antigravity muscles is at an extremely low level, but when leaning forward or backward, the activity of the lower limb muscles reaches a fairly high level. It is also known that in standing postures that require relatively large muscle strength, such as leaning forward or backward, the importance of muscle strength as a determining factor of stability increases the more the posture is tilted.

[0013] Therefore, when considering the standing posture, the antigravity muscles are more active when one assumes a posture that deviates from the upright position. Therefore, even in an environment of microgravity, for example, it is possible to train the antigravity muscles by reproducing such a posture.

[0014] FIG. 2 is a diagram showing the unconscious movements of a person to maintain a standing posture. As shown in Figure 2, when a person maintains a standing posture, the body is constantly swaying unconsciously. This swaying can be considered to be due to deviation from the target posture and the action of trying to recover from that deviation. In particular, when controlling posture in the sagittal plane (front-to-back direction of the body), control by the hip joint and ankle joint is said to be particularly important.

[0015] Taking the above into consideration, maintaining posture on the ground can be thought of as an inverted double pendulum with two joints, the hip joint (from the trunk to the head) and the ankle joint, which are controlled by the human being using the muscles attached to each joint.

[0016] Figure 3 is a model diagram showing the movement to maintain posture when deviating from the standing posture (NP). In the figure, the suffix 1 indicates the upper body and the suffix 2 indicates the lower body. The joint torques T1 and T2 associated with each joint (hip and ankle joints) when the posture deviates from NP can be calculated using the following equations (2.1) and (2.2) using the angles θ1 and θ2 of the inclination of the upper and lower body when NP is used as the reference point. T1=(M H l1+m1l g1 ) g sin(θ1 + θ2) (2.1) T2={m2l g2 +(M H +m1)l2}gsin(θ2)+T1(2.2) Equations (2.1) and (2.2) are the torques applied to the joints by gravity when a human tries to maintain a standing posture. Therefore, by applying this torque to the joints, it is possible to apply the same load to the joints in an environment without gravity as in a gravity environment.

[0017] Since equations (2.1) and (2.2) contain sine functions, it is clear that when a person leans from an upright posture, the values ​​of θ1 and θ2 become larger, and the torque applied to the joints (hip joints, ankle joints, etc.) becomes larger. For this reason, it is believed that people minimize the load on the body by naturally maintaining an upright posture when moving such as walking or running, exercising the upper limbs, or when there is a disturbance such as a fall.

[0018] On the ground, the moment around each joint increases as one moves away from the NP. For example, a typical resting posture during spaceflight in a microgravity environment resembles a fetal position with thoracic and lumbar flexion, anterior neck movement, and slight flexion of the limbs, and all antigravity muscles are relaxed.

[0019] For this reason, it has been reported that when astronauts are instructed to stand upright in a microgravity environment, they tend to lean forward. This is because, in microgravity, it is not necessary to maintain a posture that places less strain on the body, such as the NP, in response to disturbances.

[0020] Therefore, when the posture moves away from the NP, a torque is applied in the direction that disturbs the posture, similar to the action of gravity, and further, near the NP where the load is small, a constant load is generated in a random direction, for example, forward or backward. This would allow participants to train their muscles to maintain NP in a way that is close to that in a gravity environment, while being conscious of maintaining correct posture, since posture becomes even more disrupted when one's posture is poor.

[0021] [Training equipment configuration] FIG. 4 is a schematic diagram showing an example of the training device 1 according to the present embodiment. As shown in FIG. 4, the training device 1 is configured to include a base 3, a foot fixing base 4 for fixing the user's feet, a waist-lower leg fixing base 5 for fixing the user's waist to lower leg, and an upper body fixing base 6 for fixing the upper body from the waist to the head.

[0022] The base 3 is a member that functions as a foundation for the training apparatus 1. The base 3 is, for example, a rectangular plate with a length of 2000 mm and a width of 1000 mm. When used on the ground, the training apparatus 1 is placed flat on the floor with the base 3.

[0023] In this embodiment, the ground does not simply mean the earth, but also includes other planets that have gravity.

[0024] The foot fixing base 4, the waist-lower leg fixing base 5 and the upper body fixing base 6 are provided on one plate surface side of the base 3, and are arranged in the following order from one longitudinal end side of the base 3: the foot fixing base 4, the waist-lower leg fixing base 5 and the upper body fixing base 6.

[0025] The training device 1 is used by having the user lie down with the body stretched along the longitudinal direction of the base 3. In detail, the training device 1 is used in a lateral position in which the user lies down to reproduce a state approximating zero gravity and microgravity. The foot fixing base 4, the waist-lower leg fixing base 5, and the upper body fixing base 6 are configured so that the trunk is horizontal when the user is in a lateral position.

[0026] The foot support base 4 is fixed to the base 3. The position at which the foot support base 4 is fixed to the base 3 is movable along the longitudinal direction and can be adjusted according to the height of the user. In this embodiment, the foot support base 4 is configured to accommodate users with heights of 160 cm to 180 cm.

[0027] The foot support base 4 is configured to include a base support part 4A fixed to the base 3, a bottom plate 4B with which the sole of the user's foot comes into contact, and a plurality of fixing belts 4C for fixing the foot to the foot support base 4. When the user takes a lateral position on the base 3, the sole of the foot is pressed against the bottom plate 4B and fixed by the fixing belts 4C while ensuring free rotation of the foot (so as not to impede free movement of the ankle).

[0028] The waist-lower leg fixing base 5 is provided with a belt (knee joint fixing belt) for fixing the knee joint of the user, and the knee joint is fixed in an extended state.

[0029] The waist-lower leg fixing base 5 and the upper body fixing base 6 are movable on the base 3. In this embodiment, for example, ball rollers are attached to the bottom surfaces of the waist-lower leg fixing base 5 and the upper body fixing base 6, enabling movement in all directions within a plane.

[0030] Furthermore, a polyacetal flat-plate-shaped running platform 8 with low friction is provided between the lower back-lower leg fixing platform 5 and upper body fixing platform 6 and the base 3, so as not to impede the movement of the lower back-lower leg fixing platform 5 and upper body fixing platform 6. The running platform 8 should preferably be provided with a sufficient width so that the ball rollers attached to the lower back-lower leg fixing platform 5 and upper body fixing platform 6 do not fall off the running platform 8 due to the movement of the person during training.

[0031] The upper body fixing base 6 is equipped with a driving mechanism 9 that functions as a load applying means for forcibly moving the upper body fixing base 6 on the base 3. The driving mechanism 9 moves the upper body fixing base 6 along the short side direction of the base 3.

[0032] The driving mechanism 9 can be configured, for example, by utilizing a linear guide mechanism. The linear guide mechanism includes, for example, a guide rail 9A extending linearly and a stage 9C provided so as to be movable along the extension direction of the guide rail 9A, and is configured such that by rotating a ball screw built into the guide rail 9A with a motor 9B, the stage 9C attached so as to mesh with the ball screw moves linearly (moves) along the guide rail 9A. By attaching the upper body fixing base 6 to this stage 9C, the position of the upper body fixing base 6 on the base 3 can be changed.

[0033] 4 and 5, in this embodiment, the guide rail 9A constituting the drive mechanism 9 is provided so as to be positioned near the shoulder blades of the user of the training device 1. By keeping the guide rail 9A away from the ankle joint, it is possible to apply a large joint torque to the ankle joint, similar to that under gravity, while suppressing the output of the motor 9B.

[0034] The upper body fixing stand 6 is fixed to the stage 9C and comprises a base 6A that supports the upper body of the user, a backboard 6B that rises from the base 6A and to which the user's back is fixed, a pillow 6C that supports the user's head, and a belt 6D that fixes the user's body to the backboard 6B.

[0035] When the upper body fixing base 6 moves together with the stage 9C, the back plate 6B transmits the force of the upper body fixing base 6 moving to the user, and by fixing the upper body of the user with the belt 6D, the force can be transmitted not only forward but also backward to the user who is in a lateral position. The back plate 6B is rotatable with respect to the base 6A in accordance with the movement of the user's back.

[0036] In addition, a linear encoder 10 (detection means) for measuring the position of the upper body fixing base 6 is attached to the driving mechanism 9, making it possible to measure the position of the stage 9C moved by the operation of the driving mechanism 9, i.e., the position of the upper body fixing base 6, in real time. The position measured by the linear encoder 10 is output to the control device 100 and used for controlling the training.

[0037] As shown in FIG. 4, the control device 100 is configured to include an A / D converter that converts the signal output from the linear encoder 10, a load calculation means that calculates the load (the amount of movement of the stage 9C) based on the signal converted by the A / D converter, and a D / A converter and motor driver that convert the load calculated by the load calculation means into a signal to be output to the motor 9B.

[0038] FIG. 6 is a block diagram showing the processing by the load calculation means of the control device 100. As shown in FIG. The load calculation means can be configured, for example, by a so-called computer, which estimates the joint angles θ1, θ2 (see Figure 3) based on the measured upper body center of gravity position x (the position x of the upper body support base 6 measured by the linear encoder 10), and calculates the force F to be applied so that a torque simulating gravity is applied to each joint from the estimated posture. For example, as shown in FIG. 7, the force F (load) is applied according to the posture of the user.

[0039] First, the relationship between joint angles θ1, θ2 and x can be expressed by the following equation. x=l2sinθ2+l g1 sin(θ1+θ2) (3.1) Here, the joint angle θ cannot be determined because there are two angles with respect to the measurable upper body center of gravity position x. Therefore, in this embodiment, the rotation angles of the hip joint and the ankle joint are calculated as moving with the same value.

[0040] There are several methods to directly measure the joint angles θ1 and θ2, but motion capture, for example, takes up too much space for use at manned bases in space, and wearable devices lack precision. For these reasons, in this embodiment, the joint angles θ1 and θ2 are considered to change with the same value.

[0041] If the straight-line distance from the heel to the center of gravity of the upper body is L and the angle between this L and the lower leg is α, the relationship between the torque T2 applied around the ankle joint calculated using equation (2.2) and the output F of the device can be expressed by the following equation. F = T2 / Lcos(θ+α) (3.2) Using F calculated by equation (3.2), the relationship between the position x and output F for each subject was converted using a look up table calculated based on equations (2.2), (3.1), and (3.2) so that the output F was assigned to the input value (position) x (see Figure 6).

[0042] [About the evaluation experiment] In order to evaluate the effect of the training device 1 according to this embodiment, an experiment was conducted in which the myoelectric potentials were measured when training was performed using this training device (see FIG. 9) and when the same movement was performed under gravity without using the training device (see FIG. 10), and the amount of muscle activity was compared. We confirmed whether it was possible to place a load on the antigravity muscles by having subjects resist an external force applied to the upper body.

[0043] In the evaluation experiment, subjects were fitted with an electromyograph to measure muscle activity and confirm whether the trends in changes in the electromyography values ​​were similar. The subjects were five men, and their body measurements were 174.6±1.62 cm and 57.2±7.11 kg.

[0044] During the experiment, the subject was photographed by a camera while moving and the image was displayed on a display so that the subject could see to what position he or she was currently leaning.

[0045] In the evaluation experiment, the subjects lay down and tilted the center of gravity of the upper body forward by approximately 130 mm (hereafter referred to as "Keep"), and tilted backward by approximately 50 mm (hereafter referred to as "Keep back") (Figure 9). During the movement, the user was made to maintain posture based on the position of the center of gravity of the upper body, which was determined based on the value of the linear encoder 10.

[0046] For comparison, while standing, we performed two types of exercises, maintaining a forward leaning posture (hereafter referred to as "GKeep") and a backward leaning posture (hereafter referred to as "GKeep_back") that tilted the center of gravity of the upper body in a similar manner, and measured the myoelectric potential during these exercises (Figure 10).

[0047] In GKeep and GKeep_back, the subjects performed movements on a floor reaction force gauge and maintained their posture while checking the position of their center of gravity during the movements. If the device moved significantly during the experimental operation due to being unable to withstand the output or gravity, measurements were repeated. In addition, the movement was performed seven times for each trial, and the measurement time for all movements was five seconds.

[0048] In the evaluation experiment, it is estimated that in Gkeep and Keep, the dorsal muscles, gluteus maximus, and soleus muscles, which are the primary muscles for extension motion, become active, and in Gkeep_back and Keep_back, the abdominal muscles, rectus femoris, and tibialis anterior muscles, which are the primary muscles for flexion motion, become active, and the myoelectric potential value also becomes large (see Figure 8).

[0049] Myoelectric potentials were measured in the following muscles (six locations): Abdominal muscles: Approximately 23 cm outside the navel, along the fiber path Back muscles: 23cm outside the spinous process, along the fascia fibers Gluteus Maximus: Located 50% above the sacrum and femoral greater trochanter line, on the line connecting the posterior superior iliac spine and the middle of the posterior thigh Rectus femoris: Midpoint between the anterior superior iliac spine and the upper border of the patella Tibialis anterior: From the head of the fibula to the center of the lateral malleolus and 5 cm above it Soleus muscle: From the popliteal fossa to the center of the upper edge of the calcaneus and 5 cm above it

[0050] The measured EMG data was band-pass filtered (20-450Hz), full-wave rectified, low-pass filtered (10Hz), and integrated over the measurement time.These values ​​were then normalized (%MVC) by the EMG integrals during isometric maximum voluntary muscle strength (MVC) measured for each muscle to evaluate the muscle activity level during each movement.

[0051] [Experimental Results] Figures 11 and 12 are box plots of the integrated EMG values ​​for five subjects. The vertical axis shows %MVC, and the horizontal axis shows each measured muscle. As shown in Figures 11 and 12, the results showed similar trends in the changes in myoelectric potential in each muscle, both when performing movements under gravity and when performing movements using a training device to withstand a load simulating gravity.

[0052] First, in the Keep and GKeep movements shown in Figures 11 and 12, it was confirmed that the myoelectric potentials of the back and soleus muscles were larger than those of the other muscles in both movements. This is thought to be because the back muscles and soleus muscles are the primary movers in this movement (Keep, GKeep). Since agonist muscles are the muscles that play the main role in a certain movement, it is thought that the myoelectric potential, which indicates the amount of muscle activity, became larger.

[0053] In addition, in the cases of Keep_back and Gkeep_back shown in Figs. 13 and 14, it was confirmed that the myoelectric potentials of the abdominal muscles and tibialis anterior muscles were larger than those of the other muscles in both movements. This is thought to be because the abdominal muscles and tibialis anterior are the prime movers in this movement (Keep_back, Gkeep_back).

[0054] In this experiment, it was confirmed that the median myoelectric potential of the tibialis anterior and soleus muscles of the lower leg, which are the prime movers of movement, tended to be the largest compared to any other muscle. This is thought to be because when maintaining a tilted posture, the joint in the body that is subjected to the greatest torque is the ankle, and the main muscles that support the rotation of the ankle are the tibial anterior and soleus muscles, so it is thought that the large load placed on the lower leg muscles during movement caused the myoelectric potential to increase.

[0055] From these findings, it was confirmed that there was a tendency for the myoelectric potential of the agonist muscles to increase between GKeep and Keep, and between Gkeep_back and Keep_back, and it is believed that by using a training device to give a human a load that mimics gravity, it is possible to train the antigravity muscles under gravity.

[0056] From the above, it was confirmed that the changes in the myoelectric potential values ​​were similar between GKeep and Keep, and between Gkeep_back and Keep_back. It was also confirmed that among the active muscles, the calf muscles, tibialis anterior muscles, and soleus muscles each had large myoelectric potentials when they were the leading muscles in the movements. That is, it was confirmed that the training device 1 of this embodiment can train antigravity muscles.

[0057] In the above embodiment, the training is performed while lying down in an upright position, but the training may also be performed while lying down in a sitting position. In other words, by having the user train in a lying position on the ground, a condition approximating zero gravity or microgravity can be reproduced; in training in a zero gravity or microgravity space such as outer space, there are no restrictions on the installation position of the equipment (training device) or the user's position.

[0058] Furthermore, the configuration of the training device is not limited to that described in the above embodiment, but may be any configuration that includes a load application means that applies a load to cause the user to lose balance from a posture balanced with gravity on the ground, a detection means that detects the posture that has been lost due to the load applied by the load application means, and a load calculation means that calculates the load applied by the load application means based on the lost posture detected by the detection means.

[0059] In addition, the load calculation means may calculate the load to be larger as the degree of imbalance in the posture detected by the detection means increases, or may calculate the load so that a torque is applied when gravity acts on a bending joint when the balance is lost from a posture in balance with gravity on the ground. The load applying means may also be configured to apply a load in the front-to-rear direction of the body. [Explanation of symbols]

[0060] 1 training device, 9 drive mechanism, 10 linear encoder, 100 control device.

Claims

1. A training device for training antigravity muscles, comprising: a load applying means for applying a load so as to cause the robot to lose balance from a posture balanced with gravity on the ground; a detection means for detecting a posture that has been lost due to the load applied by the load application means; a load calculation means for calculating a load applied by a load application means based on the posture deviation detected by the detection means; A training device equipped with

2. 2. The training device according to claim 1, wherein the load calculation means calculates a load that increases as the degree of poor posture detected by the detection means increases.

3. 3. The training device according to claim 1, wherein the load applying means applies a load in a front-rear direction of the body.

4. 4. The training device according to claim 1, wherein the load calculation means calculates a load so that a torque is applied when gravity acts on a bending joint when the balance is lost from a posture in which balance with gravity is maintained on the ground.

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