WO2024142828A1

WO2024142828A1 - Rotating action motion assessment method, system, and program

Info

Publication number: WO2024142828A1
Application number: PCT/JP2023/043821
Authority: WO
Inventors: 公壽藤下
Original assignee: Ｍｉｒａｉ－ｗｏ合同会社
Priority date: 2022-12-28
Filing date: 2023-12-07
Publication date: 2024-07-04

Abstract

To provide a rotating action motion assessment method, system, and program, that enables visualizing and assessing bodily loads placed on joints and so forth of the body, performance, and so forth, in motion involving rotating actions with an acceleration of 9.8 m/sec2 or higher, by relative comparison between rotational coordinate system coordinate data of own rotating actions and world coordinate system data of the own rotating actions.　A rotating action motion assessment method according to the present invention includes a rotation center defining step for defining a center of rotation from an actual rotation center and/or an ideal rotation center, a step for obtaining world coordinate system coordinate data, a step for converting into rotation coordinate system local coordinate data that is local coordinate data in a rotation coordinate system of which the center of rotation within a human body in the rotating action is the origin, and an assessing step for assessing by performing relative comparison between values of two sets of data, which are the world coordinate system coordinate data of a predetermined position within the human body that is obtained from the same action in the rotating action, and the rotation coordinate system local coordinate data.

Description

Rotational motion evaluation method, system, and program

The present invention relates to a method for evaluating exercise involving rotational motion, and more particularly to a method, system, and program for evaluating rotational motion involving rotational motion with an acceleration of 9.8 m/sec ² or more.

Technologies and methods for analyzing and evaluating movement, such as motion capture and skeletal estimation, are widely used.

In particular, in the field of sports, it has become a very useful tool for performance evaluation.

However, although it is useful for evaluating performance, it does not provide a clear indicator of the physical load on the subjects. For example, in baseball, the number of pitches thrown is limited from an early age, but the incidence of shoulder and elbow injuries has not decreased.

For example, Patent Document 1 discloses a body movement analysis and visualization device. In Patent Document 1, as stated in paragraph [0010], "The three-dimensional movement measurement means generates time-series data of three-dimensional coordinate values of feature points of the body, etc. in three-dimensional space, i.e., movement data," it uses three-dimensional coordinate values of multiple predefined feature points in the human body, i.e., multiple individual, independent, fixed local coordinates (see Figure 7 in Patent Document 1). Then, optimization processing of each part is performed using a human body simulation.

However, as in Patent Document 1, when multiple independent fixed local coordinates within the human body are used to perform optimization processing for each part in a human body simulation, this is excellent for evaluating the performance of the human body's movements as viewed from these multiple fixed local coordinates (for example, whether the pitching motion maximizes the ball's exit velocity), but it is not possible to evaluate it from the perspective of the load on the body.

　In conventional body movement analysis, body movement is considered as a rigid model, so it is not possible to evaluate it from the perspective of the load on the body.

JP 10-149445 A Patent Publication 2022-155115 Patent Publication 2010-14712

As a result of the inventor's intensive research, he discovered that physical load is particularly large in movements involving rotational movements with an acceleration of 9.8 m/sec2 or ^more , and that the degree of physical load can be evaluated by treating such rotational movements as movements based on the origin of a rotational coordinate system (the only local coordinate for each time, called the center coordinate of rotation) and evaluating the movements of all joints in a unique system by relative comparison with the data in the world coordinate system of one's own movement, thus arriving at the present invention.

In other words, the present invention aims to provide a rotational movement evaluation ^method , system, and program that can visualize and evaluate the physical load on the joints of the body, performance, etc. by relatively comparing the rotational coordinate system coordinate data of one's own rotational movement with the world coordinate system data of one's own rotational movement in a movement involving a rotational movement with an acceleration of 9.8 m/sec2 or more.

The rotational movement motion evaluation method of the present invention is a rotational movement motion evaluation method that estimates and evaluates performance and/or physical load in exercise involving rotational movements with an acceleration of more than 9.8 m/ ^sec2 , and includes a rotational center definition step of defining a rotational center from at least one real rotation center and/or ideal rotation center obtained from a group of actual movements, rotational movements by skeletal estimation and motion capture, a step of obtaining world coordinate system coordinate data that is coordinate data of the world coordinate system in the rotational movement from the defined rotation center, a step of converting the world coordinate system coordinate data into rotating coordinate system local coordinate data that is local coordinate data of a rotating coordinate system with the rotational center within the human body as the origin in the rotational movement, and an evaluation step of relatively comparing and evaluating the values of two data, the world coordinate system coordinate data and the rotating coordinate system local coordinate data of a predetermined position within the human body obtained from the same movement in the rotational movement.

It is preferable that the world coordinate system coordinate data is world coordinate data that indicates the world coordinates of a predetermined position inside the human body for each time, and the rotational coordinate system local coordinate data is local coordinate data that indicates the local coordinates of a predetermined position inside the human body for each time, with the center of rotation inside the human body as the origin during the rotational movement.

It is preferable that the evaluation step is a step of evaluating by relative comparison the speed or acceleration shown for each time at a given position in the human body.

The evaluation is an evaluation of physical load, and the two data, the world coordinate system coordinate data and the rotating coordinate system local coordinate data, are data relating to the speed or acceleration shown at each time at a specific position in the human body, and it is preferable to determine that the physical load is high when the maximum speed or maximum acceleration of the rotating coordinate system local coordinate data is close to or greater than the maximum speed or maximum acceleration of the world coordinate system coordinate data.

The evaluation is an evaluation of physical load, and the two pieces of data, the world coordinate system coordinate data and the rotating coordinate system local coordinate data, are data relating to the area of a graph of velocity shown for each time at a specific position in the human body or the displacement of a specific position in the human body, and it is preferable to determine that the physical load is high when the area of the graph of velocity shown for each time at a specific position in the human body or the displacement of a specific position in the human body in the rotating coordinate system local coordinate data is close to or greater than the area of the graph of velocity shown for each time at a specific position in the human body or the displacement of a specific position in the human body in the world coordinate system coordinate data.

The rotation center definition process preferably includes a process of evaluating the rotation center coincidence rate between the actual rotation center and the ideal rotation center.

The method for converting coordinate data in a rotational movement of the present invention is a method for converting coordinate data in a rotational movement used in the method for evaluating a rotational movement, and includes the steps of: a rotational center definition step of defining a ^rotational center from at least one real rotation center and/or an ideal rotation center obtained from a group of actual movements, rotational movements by skeletal estimation and motion capture, in a movement involving a rotational movement with an acceleration exceeding 9.8 m/sec2; a step of obtaining world coordinate system coordinate data, which is coordinate data of a world coordinate system showing the world coordinates of a predetermined position in the human body during the rotational movement for each time from the defined rotational center; a step of defining a center coordinate of the world coordinate system coordinate data for each time; a step of matching one axis of a Cartesian coordinate system with a line segment connecting the center coordinate and a predetermined joint position to obtain Cartesian coordinate system data; and a step of converting the Cartesian coordinate system data into local coordinate data showing the local coordinates of a predetermined position in the human body for each time, the local coordinates having the rotational center in the human body as the origin during the rotational movement.

The rotational movement motion evaluation system of the present invention is a rotational movement motion evaluation system that estimates and evaluates performance and/or physical load in exercise involving rotational movements with an acceleration of more than 9.8 m/ ^sec2 , and includes a rotational center definition device that defines a rotational center from at least one real rotation center and/or ideal rotation center obtained from a group of actual movements, rotational movements by skeletal estimation and motion capture, a world coordinate system coordinate data acquisition device that obtains world coordinate system coordinate data, which is coordinate data of the world coordinate system in the rotational movement from the defined rotation center, a conversion device that converts the world coordinate system coordinate data into rotating coordinate system local coordinate data, which is local coordinate data of a rotating coordinate system whose origin is the rotational center within the human body in the rotational movement, and a relative comparison device that relatively compares the values of two data, the world coordinate system coordinate data and the rotating coordinate system local coordinate data of a predetermined position within the human body, obtained from the same movement in the rotational movement.

The evaluation is an evaluation of physical load, and the two data, the world coordinate system coordinate data and the rotating coordinate system local coordinate data, are data relating to the speed shown at each time at a specific position in the human body, and it is preferable that the physical load is determined to be high when the speed of the rotating coordinate system local coordinate data is close to or greater than the speed of the world coordinate system coordinate data.

The coordinate data conversion system for rotational movement of the present invention is a coordinate data conversion system for rotational movement used in the rotational movement evaluation system, and includes: a rotational center definition device that defines a rotational center from at least one ^real rotation center and/or ideal rotation center obtained from a group of actual movements, rotational movements by skeletal estimation and motion capture, in a movement involving rotational movements with an acceleration exceeding 9.8 m/sec2; a world coordinate system coordinate data acquisition device that obtains world coordinate system coordinate data, which is coordinate data of the world coordinate system that shows the world coordinates of a predetermined position within the human body during the rotational movement for each time from the defined rotational center; a device that defines the center coordinate of the world coordinate system coordinate data for each time; a device that obtains orthogonal coordinate system data by matching one axis of an orthogonal coordinate system with a line segment connecting the center coordinate and a predetermined joint position; and a conversion device that converts the orthogonal coordinate system data into local coordinate data that shows the local coordinates of a predetermined position within the human body for each time, with the rotational center within the human body as the origin during the rotational movement.

The first aspect of the program of the present invention is a program for causing a computer to function as each device in the rotational motion evaluation system.

The second aspect of the program of the present invention is a program for causing a computer to function as each device in a coordinate data conversion system for the rotational motion.

According to the present invention, in a movement involving a rotational movement with an acceleration of 9.8 m/sec2 or ^more , a rotational movement motion evaluation method, system, and program can be provided that can visualize and evaluate the physical load on the joints of the body, performance, etc. by relatively comparing the rotational coordinate system coordinate data of one's own rotational movement with the world coordinate system data of one's own rotational movement, thereby achieving the remarkable effect of providing the method, system, and program.

1A and 1B are schematic diagrams of human joints, in which (a) shows the joint in its normal state, (b) shows the joint being compressed, and (c) shows the joint being pulled. The coordinate system symbols for the world coordinate system and the rotating coordinate system are shown below. This shows a model that does not deviate from a circular orbit in the world coordinate system. This shows a model that deviates from a circular orbit in the world coordinate system. A model that does not deviate from a circular orbit in a rotating coordinate system is shown. A model that deviates from a circular orbit in a rotating coordinate system is shown. 13 is a diagram showing a schematic diagram of calculation of a rotation center for a person performing a pitching motion of a baseball toward the player using his left arm as a rotational motion. FIG. FIG. 8 is an explanatory diagram of conversion of the movement in FIG. 7 from a world coordinate system to a rotation axis coordinate system. FIG. 8 is an explanatory diagram of conversion of the movement in FIG. 7 from a world coordinate system to a rotation axis coordinate system. FIG. 8 is an explanatory diagram of conversion of the movement in FIG. 7 from a world coordinate system to a rotation axis coordinate system. FIG. 8 is an explanatory diagram of conversion of the movement in FIG. 7 from a world coordinate system to a rotation axis coordinate system. FIG. 8 is an explanatory diagram of conversion of the movement in FIG. 7 from a world coordinate system to a rotation axis coordinate system. FIG. 8 is an explanatory diagram of conversion of the movement in FIG. 7 from a world coordinate system to a rotation axis coordinate system. FIG. 4 is an explanatory diagram of an ideal center of rotation. FIG. 1 is a block diagram of a rotational motion evaluation system of the present invention. 1 is a flowchart of a rotational motion evaluation system of the present invention. This is a graph showing an example of an analysis in the world coordinate system of the elbow load during the pitching motion of a left-handed pitcher in the low stress case. This is a graph showing an example of an analysis of the elbow load during the pitching motion of a left-handed pitcher in a rotating coordinate system, in the case of low stress. 19 is a graph showing a relative comparison of acceleration from the data in FIG. 17 and FIG. 18. 19 is a graph showing a relative comparison of displacement from the data in FIG. 17 and FIG. 18. This is a graph showing an example of an analysis in the world coordinate system of the elbow load during the pitching motion of a right-handed pitcher, in the case of huge stress. This is a graph showing an example of an analysis in a rotating coordinate system of the elbow load during the pitching motion of a right-handed pitcher, in the case of huge stress. 23 is a graph showing a relative comparison of acceleration from the data in FIG. 21 and FIG. 22. 23 is a graph showing a relative comparison of displacement from the data in FIG. 21 and FIG. 22.

The following describes embodiments of the present invention, but these embodiments are shown as examples, and it goes without saying that various modifications are possible without departing from the technical concept of the present invention. In the drawings, identical parts are represented by the same reference numerals.

As an example of a movement involving a rotational movement with an acceleration of 9.8 m/sec2 or ^more , let us consider the pitching motion of a baseball pitcher. Since the factors that lead to injuries to the shoulders and elbows of baseball pitchers include not only the number of pitches but also the load placed on the pitcher, it is necessary to take into account the load placed on the pitcher. In other words, it is necessary to consider not only the number of pitches but also the load placed on the pitcher during exercise (the load placed on the pitching motion).

Even if a pitcher is using what is generally considered to be a correct form that is less likely to cause injury, it is impossible to determine whether the exercise places excessive strain on the pitcher's arms and shoulders, even if one assumes a rigid model and analyzes whether the model is throwing exactly like the model. In this invention, the human body is considered as a semi-rigid model, and we have succeeded in elucidating the load on the joints during exercise that involves rotational movements.

<About joints>
FIG. 1 shows a schematic diagram of a human joint. The joint 14 connecting the

bones

10 and 12 shown in FIG. 1(a) is formed of ligaments, cartilage, muscles, etc., and can be understood as an elastic body mechanically, and is a semi-rigid part. It is believed that the cause of the joint failure (injury) is the application of excessive stress (mainly tension) to this elastic body. If the joint connecting the bones is considered to be an elastic body, when the joint 14 is compressed as shown in FIG. 1(b), the bones interfere with each other, so it is thought that compression is not a problem as long as it is not compressed beyond the limit of the Poisson's ratio. On the other hand, when the joint 14 is pulled as shown in FIG. 1(c), it is a problem, and it is thought that the cause of damage to the ligaments surrounding the joint and connecting it in particular is the application of excessive tensile load to the joint.

1. About impulse
The force F is integrated over time t to obtain the impulse. In the following equation, m is mass, a is acceleration, v is velocity, and n is the number of loads (in the case of a pitcher, the number of pitches).

Here, if there is no fluctuation in m _i or it can be ignored,

[C is an integral constant]

2. <About velocity components>
From the above, if we assume that there is no change in mass m during exercise, or that the amount of change can be ignored, then the load on the body can be evaluated using the time component of velocity (vt).

3-1. <Relationship between velocity components and impulse>
[World coordinate system model]
If we consider the velocity components as parameters of impulse, then we can consider the velocity components of the world coordinate system as parameters of impulse with respect to the world coordinate system (Earth). In other words, the movement with respect to the Earth as seen in the world coordinate system can be considered as the performance of the movement action. Figure 2 shows the coordinate system symbols of the world coordinate system and the local rotating coordinate system described later.

[World coordinate system: model that does not deviate from a circular orbit]
As shown in Figure 3, when an arbitrary object 16 accelerates on a circular orbit from position Pos.1 (coordinates: _x1 , _y1 , _z1 ) to position Pos.2 (coordinates: _x2 , _y2 , _z2 ) between time _t1 and _t2 , the accelerations _a1 and _a2 are expressed as the difference between velocities _v2 and _v1 . The average velocity v at that time is expressed as follows:

In FIG. 3, reference numeral 18 denotes the center of the circular orbit.

[World coordinate system: model deviating from circular orbit]
On the other hand, as shown in FIG. 4, if another arbitrary object 16 deviates from the circular orbit and accelerates, the acceleration is expressed as the difference in velocity vectors, just like the model that does not deviate from the circular orbit. Also, the average velocity v' at that time is expressed as follows:

It becomes.

In this way, even when considering the world coordinate system, it is not possible to determine whether or not the average speed obtained from the world coordinate system has deviated from a circular orbit. Note that there are cases where a model that does not deviate from a circular orbit and a model that does deviate from a circular orbit show the same value (average speed).

3-2. <Relationship between velocity components and impulse>
[Rotating coordinate system model]
Since the axis of rotation in rotational movements differs from person to person, even if we consider it in the world coordinate system, we can only tell whether the form is as shown in the example. However, if we consider the velocity component as an impulse parameter, the velocity component of the rotational coordinate system when the rotation center coordinates in the body of the person performing the rotational movement are defined can be considered as an impulse parameter for the rotational coordinate system (body; torso). And the movement of the body can be considered as a physical load.

[Rotating coordinate system: model that does not deviate from a circular orbit]
As shown in Fig. 5, when an object associated with an arbitrary object (e.g., an object connected to an elbow like a shoulder) exists and moves in conjunction with the arbitrary object, the coordinates are converted into those of the local rotating coordinate system by matching a line segment connecting the associated object with the center coordinates with one axis. The local rotating coordinate system may be simply called a "rotating coordinate system" in this specification. That is, for example, the rotating coordinate system local coordinate data may be simply called "rotating coordinate system coordinate data".

By converting the data in the world coordinate system into data in the rotating coordinate system, it is possible to calculate the average velocity in the rotating coordinate system. The average velocity _vR in the rotating coordinate system of an object moving on a circular orbit is given by:

Since the direction of rotation of the axis of rotation and the direction of rotation of the motion are the same, v> _vR . (v>> _vR )
Because the speed of the rotating coordinate system is slower than that of the world coordinate system, the difference in speed is also smaller, the acceleration approaches a centripetal force toward the center, and the force acting on the joints has a larger compressive load component.

[Rotating coordinate system: model deviating from circular orbit]
A model that deviates from the circular orbit of the rotating coordinate system is shown in Figure 6. As in Figure 5, when an object associated with an arbitrary object (e.g., an object connected to an elbow like a shoulder) exists and moves in conjunction with the object, the coordinates are converted to those of the rotating coordinate system by matching a line segment connecting the associated object and the center coordinate with one axis.
The average velocity of the model deviating from a circular orbit in the rotating coordinate system is

It becomes.
Even when v'> _vR ', _vR '/v' is greater than _vR /v, and when v' and _vR ' are close or v'≦ _vR ', there is a high possibility that the circular orbit has deviated, so it can be determined that the circular orbit has deviated. Since it can be considered that "deviation from a circular orbit = excessive tensile load is being applied," it is possible to determine the load during rotational operation.

4. 　In this way, the two (impulse) data in the world coordinate system and the local rotating coordinate system of the mover, generated from the same movement, have the same dimensions (unit system), making relative comparison possible.

5. 　If the speed of the local rotating coordinate system of the mover, generated from the same movement, is equal to or close to the speed in the world coordinate system, it can be determined that the movement deviates from a circular orbit. In addition, various evaluations can be made by relatively comparing the two (impulse) data of the world coordinate system and the mover's local rotating coordinate system.

[Calculate rotation center]
The method of calculating the center of rotation in the rotating coordinate system model will be explained next. Figure 7 shows a diagram in which the spine of a person using his left arm to pitch a baseball towards us as a rotational motion is represented as a straight line NW, and the straight lines connecting the left shoulder LS and right shoulder RS of the person making the rotational motion, that is, the straight lines R1 and L1 connecting the left shoulder and right shoulder, are represented as straight lines LS and RS.
A rotation center coordinate point C ( _xc , _yc , _zc ) is found on the straight line NW shown in FIG. 7 and has the shortest distance from the straight lines LS and RS.

Unit vector of straight line LS RS

of

In this way, the coordinates of point C, the center of rotation, are determined when the spine of the person performing the rotational movement is defined as the straight line NW, and the left and right shoulders of the person performing the rotational movement are defined as the straight lines LS and RS. When positioning each part of the spine, left and right shoulders (i.e., in the above example, positioning the straight line NW, and the straight lines LS and RS), positioning may be performed from a video of the actual rotational movement, or the rotational movement may be replaced with a rotational movement obtained by skeletal estimation or motion capture. An example of skeletal estimation is shown in Patent Document 2, and an example of motion capture is shown in Patent Document 3. Using these technologies, each part related to the axis of rotation of the rotational movement, such as the spine, left arm and right arm, can be positioned.

[Transformation from world coordinate system to rotation axis coordinate system]
Next, a method of conversion from the world coordinate system to the rotation axis coordinate system will be explained. Fig. 8 shows a rotational motion in which the spine of a person pitching a baseball toward the viewer with his/her left arm is a straight line NW, the left arm of the person making the rotational motion is a straight line LA, and the right shoulder is RS. In Fig. 8, the shoulder of the left arm is LS (coordinates _xL , _yL , _zL ), and the elbow of the left arm is LE (coordinates _xE , _yE , _zE ). The center of rotation is the coordinates ( _xC , _yC , _zC ) of point C on the spine that is the shortest distance from the straight line connecting the left shoulder LS and the right shoulder RS obtained as described above. At this stage, the coordinates are in the world coordinate system.

Next, as shown in FIG. 9, the coordinate origin of the rotation axis coordinate system is moved to the rotation center coordinate point C, and the coordinates of the shoulder LS and elbow LE of the left arm are transformed.

Next, a unit vector for Y-axis rotation from the rotation center coordinate point C toward the left shoulder LS is obtained (see FIG. 10). Then, the trigonometric function of the transformation determinant is obtained from the Euler angles of the unit vector.

Then, the Y-axis rotation transformation

It becomes.

Next, the coordinates of each part of the left arm's shoulder LS and left arm's elbow LE are transformed by rotating the body about the Y axis using the transformation matrix thus obtained (see FIG. 11).

Next, a unit vector for Z-axis rotation from the rotation center coordinate point C toward the left shoulder LS is obtained (see FIG. 12). Then, the trigonometric function of the transformation determinant is obtained from the Euler angles of the unit vector.

Then, the Z-axis rotation transformation

And then,

This completes the transformation to a coordinate system with the center of rotation as the origin and the axes fixed within the body. By transforming all records with the same definition, it becomes possible to handle them as rotating coordinate systems.

The coordinates of each part of the left arm, shoulder LS and elbow LE, are transformed by rotating around the Z axis using the transformation matrix obtained. The line connecting the center coordinate of the rotational movement and point LS coincides with the X axis (see Figure 13). The above transformation is performed for each part and each time, and the measurement data is transformed into a group of coordinates in the rotating coordinate system.

In the example of a pitching motion, the above conversion is performed for each part of the body at each time: the neck, waist, right shoulder, left shoulder, right elbow, and left elbow, and the measurement data is converted into a group of coordinates in a rotating coordinate system.

Then, the velocity v for each time in the group of coordinates in the rotating coordinate system is calculated based on the following formula.

[n is a natural number]

　Above, we have explained the conversion from the definition of the center of rotation in the case of rotational movements such as video data of actual movements, skeletal estimation based on actual movements, or motion capture based on actual movements. The definition of the center of rotation in the above explanation is, so to speak, a real center of rotation that exists in actual rotational movements.

The above describes an actual center of rotation based on an actual rotational movement, but even in the case of motion capture based on actual movements, for example, depending on the type of motion capture, there are some cases where information about the spine of the person performing the rotational movement is not available. Without information about the spine, it is not possible to position each part of the spine, left arm, and right arm described above.

[Ideal rotation center]
Even if such information about the spine is not available, it is possible to define the center of rotation by considering an ideal center of rotation.

The ideal rotation center coordinate point Ci shown in FIG.

It is defined as:

The above ideal center of rotation can also be used to calculate the center of rotation in a rotating coordinate system model.

In addition, performance can be evaluated at this point by evaluating the degree of agreement between the ideal center of rotation and the actual center of rotation near the maximum speed.

[Rotation center coincidence rate]
The distance from the origin O of the world coordinate system to the rotation center coordinate point C shown in FIG.

The distance from the origin O of the world coordinate system to the ideal rotation center coordinate point Ci shown in FIG.

Then,
The center coordinate coincidence rate between the rotation center coordinate point C and the ideal rotation center coordinate point Ci is

It becomes.

Rotation center coincidence rate (1)
[Rate of coincidence between the center of rotation at maximum speed and the center of rotation at each time of rotational movement]
The rotation center coincidence rate, as viewed from the center of rotation at the time of maximum velocity and the center of rotation at each time of rotational motion, can be used to evaluate the performance of rotational motion (for example, pitching motion in baseball). By looking at this rotation center coincidence rate, it can be used to determine whether the body is shaking at the final acceleration of the rotational motion (for example, when the ball is released). If the center of rotation is shaking, energy is also used in the translational motion, which is thought to reduce efficiency. In this case, for example, in the case of pitching motion in baseball, the evaluation is based on the center of rotation at the time of maximum velocity of the elbow or wrist (when the ball is released). If there is no data on the spine of the actual rotation center, the rotation center coincidence rate, as viewed from the center of rotation at the time of maximum velocity and the center of rotation at each time of rotational motion, can be seen by substituting the ideal center of rotation for the central coordinates at each time. In other words, the efficiency of the actual motion can be evaluated by looking at the rotation center coincidence rate, as viewed from the center of rotation at the time of maximum velocity and the center of rotation at each time of rotational motion.

Rotation center coincidence rate (2)
[Rate of agreement between ideal and actual rotation centers]
Also, when considering the rotation of the torso in a rotational motion such as pitching, it is considered ideal that the center of rotation is located at the midpoint of the line connecting the right shoulder and the left shoulder. If the agreement rate between the ideal center of rotation near the maximum speed and the real center of rotation, which is the actual center of rotation, is not 100%, the athlete (for example, a pitcher) still has room to improve the efficiency of the rotational motion. In other words, the efficiency of the rotational motion mechanics can be evaluated by looking at the agreement rate between the ideal center of rotation and the real center of rotation. In summary, if the center of rotation near the maximum speed is the ideal center of rotation, the motion mechanics of the pitcher's torso can be evaluated as being in the best state for rotational motion. Note that, if it is necessary to analyze a motion without information data on the spine, it is not possible to evaluate the efficiency of the mechanics by looking at the agreement rate between the ideal center of rotation and the real center of rotation. This is because the ideal rotation coordinates are substituted for the central coordinates of each data.

Next, an embodiment of the rotational motion evaluation system of the present invention will be described. A block diagram of an embodiment of the rotational motion evaluation system of the present invention is shown in Figure 15.

The rotational motion assessment system 20 of one embodiment shown in FIG. 15 includes a server 30, a terminal device 32, and a communication network 34. The memory unit 22 and the control unit 26 are stored in the server 30, and are connected to the terminal device 32 via a communication network 34 such as the Internet or an in-house LAN (Local Area Network).

The terminal device 32 is equipped with an information input operation unit 24 and a display unit 28. Furthermore, the terminal device 32 is equipped with an input unit 36, a communication interface 38, RAM/ROM 40, a CPU (control device/arithmetic unit) 42, a memory (main storage device) 44, and a display interface 46. A keyboard or touch panel can be used as the information input operation unit 24, and an LCD display, for example, can be used as the display unit 28. The terminal device 32 can be various computers, and can also be a mobile terminal type computer such as a smartphone or tablet.

As the information input, at least one real rotation center obtained from the group of actual movements, skeletal estimation, and rotation movements by motion capture is input, or an ideal rotation center is input. Alternatively, at least one real rotation center obtained from the group of actual movements, skeletal estimation, and rotation movements by motion capture and an ideal rotation center may be input to define the rotation center. The actual movements include various actual movements such as videos of actual movements, actual movements recorded on a recording medium, and live view images. Here, the input of the actual movements is, for example, the input of a captured image of the actual movements. The captured images of the actual movements include both still images and videos. As the input of rotation movements by skeletal estimation, for example, information on the skeletal estimation during the rotation movements can be input using an application that performs skeletal estimation from a captured image of the actual movements. Also, as the rotation movements by motion capture, for example, information on the motion capture during the rotation movements can be input using an application that performs motion capture from a captured image of the actual movements. The real center of rotation can be obtained from a group of actual movements, skeletal estimation, and rotational movements obtained by motion capture. The real center of rotation can be calculated from at least one of these groups, or can be automatically detected from at least one of these groups. Note that the real center of rotation can be obtained by combining any of these groups, for example, actual photographed images and skeletal estimation. Such information is input from the information input operation unit 24.

Based on the input information, the display unit 28 outputs the rotational movement exercise evaluation. All of this input to output can be done by a program. When using a program to do everything on the system, the only user information to be input is the ID (name, height, registration number, etc.),
All of the steps from capturing the rotational motion → outputting a world coordinate system data group → detecting the center of rotation → converting to a rotational coordinate system → verification can be done automatically. Also, if the rotational motion is the motion of throwing a baseball, it is also possible to automatically define left-handed or right-handed throwing by detecting the direction in which the ball is thrown. For example, if a camera is set in the information input operation unit 24, then by inputting user information from the information input operation unit 24 and inputting an image from the information input operation unit 24, all of the steps from input to output of evaluation can be done automatically on the system.
Furthermore, in the illustrated example, an example of a rotational movement evaluation system 20 is shown, but with a similar configuration, by simply changing the program, it can also be made into a coordinate data conversion system for rotational movement that performs conversion of coordinate data in rotational movement.

The first aspect of the program of the present invention is a program for making a computer function as each device in a rotational motion evaluation system 20. That is, the first aspect of the program of the present invention makes a computer function as each device in a rotational motion evaluation system including a rotational center definition device that defines a rotational center from at least one real rotational center and/or ideal rotational center obtained from a group of actual movements, skeletal estimation, and rotational movements by motion capture, a world coordinate system coordinate data acquisition device that obtains world coordinate system coordinate data, which is coordinate data of the world coordinate system in the rotational movement from the defined rotational center, a conversion device that converts the world coordinate system coordinate data into rotational coordinate system local coordinate data, which is local coordinate data of a rotational coordinate system whose origin is the rotational center inside the human body in the rotational movement, and a relative comparison device that relatively compares the values of the two data, the world coordinate system coordinate data and the rotational coordinate system local coordinate data, obtained from the same movement in the rotational movement.

The second aspect of the program of the present invention is a program for making a computer function as each device in a coordinate data conversion system. That is, the second aspect of the program of the present invention makes a computer function as each device in a coordinate data conversion system in a rotational motion, including a rotational center definition device that defines a rotational center from at least one real rotational center and/or ideal rotational center obtained from a group of actual motion, skeletal estimation, and rotational motion by motion capture, a world coordinate system coordinate data acquisition device that obtains world coordinate system coordinate data, which is coordinate data of the world coordinate system that indicates the world coordinates of a predetermined position in the human body in the rotational motion for each time from the defined rotational center, a device that defines the center coordinate of the world coordinate system coordinate data for each time, a device that obtains orthogonal coordinate system data by matching one axis of an orthogonal coordinate system with a line segment connecting the center coordinate and a predetermined joint position, and a conversion device that converts the orthogonal coordinate system data into local coordinate data that indicates the local coordinates of a predetermined position in the human body for each time, with the rotational center in the human body as the origin.

In the illustrated example, the terminal device 32 and the server 30 are connected via the communication network 34, but it is also possible to input all programs into the terminal device 32 without using the communication network 34 and have the terminal device 32 function offline as a rotational motion evaluation system, or as a coordinate data conversion system.

FIG. 16 shows a flowchart illustrating one embodiment of the rotational movement evaluation method in the rotational movement evaluation system 20 of the present invention. FIG. 16 shows a pattern in which a rotation center is defined from an actual rotation center using skeletal estimation. In the example shown in FIG. 16, the computer processing is broadly divided into three parts: a part in which skeletal estimation is performed in the rotational movement evaluation system 20, an analysis part in which analysis is performed in the rotational movement evaluation system 20, and a display part in which the evaluation of the rotational movement is displayed in the rotational movement evaluation system 20.

The steps in the flowchart in FIG. 16 are as follows. Note that the flowchart in FIG. 16 is merely one embodiment, and it goes without saying that changes such as the order of the steps or the deletion or addition of steps can be made by modifying the program.

[Step (S) described in FIG. 16]
S100: <Video Recording Step> Video recording of an actual rotational motion, for example, a baseball pitching motion, is performed.
S102: <Skeletal Estimation Step> Skeletal estimation is performed using a skeletal estimation technique from the photographic data captured in S100. For example, the skeletal estimation technique disclosed in Japanese Patent Laid-Open No. 2003-233999 and various other known skeletal estimation techniques can be used for skeletal estimation.
S104: <Three-dimensional coordinate detection step> Three-dimensional coordinates are detected from the skeleton estimation in the rotational motion.
S106: <Three-dimensional coordinate data extraction step> The detected three-dimensional coordinate data is extracted.
S108a: <Body frame image insertion step> A body frame image is inserted. At this time, the body frame definition file in the database in S107 is referenced (S107: body frame definition file reference step).
S110: <Bone structure estimation video step> Displaying a bone structure estimation video Here, rather than performing evaluation through relative comparison, the bone structure estimation video is displayed for reference.

The next step includes a step of converting coordinate data from the world coordinate system to a rotating coordinate system, which is a characteristic step of the present invention.
S108b: <Three-dimensional coordinate-time data acquisition step [world coordinate system]> Time-based data of three-dimensional coordinates in the world coordinate system is acquired.
S112: <Rotation center coordinate calculation step> The rotation center coordinate is calculated from the three-dimensional coordinate data in S108b. At this time, the rotation center coordinate calculation object skeleton definition file in the database is referenced in S111 (S111: rotation center coordinate calculation object skeleton definition file reference step).
S114: <3D coordinates/rotation center coordinates-time data acquisition step [world coordinate system]>
Three-dimensional coordinate data in the world coordinate system is acquired for each time period.
S116a: <Unit Vector Calculation Step (During Rotation--Target Joint)> A unit vector of a joint that is an evaluation target during a rotational motion is calculated.
S118: <Unit Vector and Euler Angle Calculation Step> A unit vector and an Euler angle are calculated.
S120: <Coordinate conversion step> The coordinate axes are converted from the world coordinate system to a rotating coordinate system.
S122: <Three-dimensional coordinate-time data acquisition step [rotating coordinate system]> Three-dimensional coordinate data in a rotating coordinate system for each time period is acquired.
S124: <Joint part velocity calculation step [rotating coordinate system]> The velocity of the joint part in the rotating coordinate system is calculated.
S125: <Step for evaluating relative joint position (straight line matching rate) [rotating coordinate system]> The relative joint position (straight line matching rate) of the joint part to be evaluated in the rotating coordinate system is evaluated and displayed. This step can be provided as necessary. For example, in terms of the rotational motion of pitching, the linear matching rate between the line R1 from the spine to the right shoulder and the line L1 from the spine to the left shoulder shown in FIG. 7 can be evaluated, or the linear matching rate between the line R1 from the spine to the right shoulder and the line LA from the spine to the left arm can be evaluated. It can be evaluated that the higher the linear matching rate, the closer the rotational motion is to the ideal.
S126: <Step of Drawing a Speed-Time Graph [Rotating Coordinate System]> A graph showing the speed of the joint part to be evaluated in the rotating coordinate system over time is drawn and displayed.
S127: <Acceleration-time graph drawing step [rotating coordinate system]> A graph showing the acceleration over time in the rotating coordinate system of the joint part that is the evaluation target is drawn and displayed.

On the other hand, world coordinate system data for relative comparison with the local coordinate data of the rotating coordinate system is also acquired in the next step.
S116b: <Joint velocity calculation step [world coordinate system]> The velocity of the joint in the world coordinate system is calculated.
S128: <Step of calculating peak velocity (Vmax) of target joint [world coordinate system]> The peak velocity (Vmax) in the world coordinate system of the joint part that is the evaluation target is calculated.
S130: <Calculation of ideal rotation center [world coordinate system]> If necessary, the coordinates of the ideal rotation center are calculated.
S131: <Rotation center coordinate agreement rate [world coordinate system]> The agreement rate between the rotation center coordinates in the world coordinate system of the joint part to be evaluated and the ideal rotation center coordinates is evaluated and displayed. This step may be provided as necessary.
S132: <Step of Drawing a Speed-Time Graph [World Coordinate System]> A graph showing the speed of the joint portion to be evaluated in the world coordinate system over time is drawn and displayed.
S133: <Acceleration-time graph drawing step [world coordinate system]> A graph showing the acceleration of the joint part to be evaluated in the world coordinate system over time is drawn and displayed.

Next, the obtained local coordinate data in the rotating coordinate system and the coordinate data in the world coordinate system are relatively compared and evaluated.
S135: <Relative comparison evaluation step> The obtained local coordinate data in the rotating coordinate system and the coordinate data in the world coordinate system are relatively compared and evaluated. In this relative comparison, for example, a graph showing the velocity in the rotating coordinate system of a predetermined position in the human body that is the evaluation target of S126, such as a joint, over time, is compared and evaluated with a graph showing the velocity in the world coordinate system of the joint that is the evaluation target of S132 over time.

As a criterion for evaluating the relative comparison between the velocities in the rotating coordinate system and the world coordinate system, if the maximum velocity of the rotating coordinate system local coordinate data is close to or greater than the maximum velocity of the world coordinate system coordinate data, it can be determined that the physical load is large.
<Evaluation: Low load>
If the maximum speed of the joint part that is the evaluation target in the world coordinate system is 100%, the maximum speed of the joint part that is the evaluation target in the rotational coordinate system is 60% or less.
This pitching motion places less strain on the joints, and is less likely to cause injury even if the pitching motion is continued.
<Evaluation: Medium load>
If the maximum speed of the joint part that is the evaluation target in the world coordinate system is 100%, the maximum speed of the joint part that is the evaluation target in the rotational coordinate system is more than 60% and is 80% or less.
It is believed that a considerable amount of strain is being placed on the joint in question, and caution is required if such a pitching motion is continued.
<Evaluation: Heavy load>
If the maximum speed of the joint part serving as the evaluation target in the world coordinate system is 100%, the maximum speed of the joint part serving as the evaluation target in the rotating coordinate system exceeds 80%.
This pitching motion places a great strain on the relevant joints, and there is a high possibility of injury if such a pitching motion is continued.

In addition, in the relative comparison evaluation step of S135, for example, a maximum acceleration of a graph showing the acceleration in the rotating coordinate system of the joint part, which is the evaluation target of S127, for each time, is relatively compared with a maximum acceleration of a graph showing the acceleration in the world coordinate system of a predetermined position in the human body, for example, a joint, which is the evaluation target of S133, for each time, and if the maximum acceleration in the rotating coordinate system is close to or greater than the maximum acceleration in the world coordinate system, it can be determined that the load on the joint part is large. In addition, a relative comparison is made between the areas of the graphs of the speeds shown for each time of the rotating coordinate system and the world coordinate system of a predetermined position in the human body, and if the area of the graph of the speeds shown for each time of the rotating coordinate system is close to or greater than the area of the graph of the speeds shown for each time of the world coordinate system, it can be determined that the load on the predetermined position in the human body, for example, a joint part, is large.
In addition, by relatively comparing the displacement of a specific position within the human body in the rotating coordinate system and the world coordinate system, if the displacement in the rotating coordinate system is close to or greater than the displacement in the world coordinate system, it can be determined that the load on the specific position within the human body, such as a joint, is large.

The present invention is characterized by the fact that it does not compare data with that of others, but with one's own data. Therefore, although physical loads such as the load on joints caused by rotational movements vary from person to person, by comparing with one's own data, it is now possible to visualize, i.e., quantify, and evaluate physical loads, which was not possible before. Furthermore, in addition to evaluating physical loads such as the load on joints caused by rotational movements, the rotational movement motion evaluation system and rotational movement motion evaluation method of the present invention can also evaluate performance due to rotational movements by relatively comparing the data in the rotational coordinate system with the data in the world coordinate system.

Next, an embodiment will be described. In the present invention, the center of rotation may be at least one real center of rotation obtained from the group of actual movements, skeletal estimation, and rotation movements by motion capture, and/or an ideal center of rotation may be used.

Example 1
A left-handed pitcher A was actually asked to throw a baseball with his left arm, and a video of the left arm pitching was taken. The center of rotation was calculated based on skeletal estimation from the video. Then, the speed of the elbow in the left arm pitching motion was calculated for each time in the world coordinate system and the local rotating coordinate system. FIG. 17 shows a graph of the results in the world coordinate system. The maximum speed Vmax in the world coordinate system was 16.19 m/sec. FIG. 18 shows a graph of the results of the speed per time in the rotating coordinate system. In a relative comparison, the speed per time in the rotating coordinate system was 8.67 m/sec, even at the maximum speed Vmax, which is much slower than the maximum speed Vmax of the world coordinate system of 16.19 m/sec (53.55% when the maximum speed in the world coordinate system is 100%), and it can be determined that the load on the elbow in the left arm pitching motion is small. There is little possibility of injury even if such a pitching motion is continued.
19 shows the results of calculating the acceleration over time of the elbow in the world coordinate system and the local rotating coordinate system and comparing them relative to each other for the left arm's pitching motion. Since the maximum acceleration of the rotating coordinate system is neither close to nor exceeds the maximum acceleration of the world coordinate system, it can be determined that the load on the elbow, which is the joint in question, is small.
20 shows the results of calculating and relatively comparing the displacement of the elbow in the world coordinate system and the local rotating coordinate system for the elbow during the pitching motion of the left arm. Since the displacement of the elbow in the rotating coordinate system is neither close to nor exceeds the displacement of the elbow in the world coordinate system, it can be determined that the load on the elbow, which is the joint in question, is small.

Example 2
Next, the center of rotation was calculated based on the skeleton estimation from a recorded video of right-handed pitcher B throwing a baseball with his right arm. Then, the velocity of the elbow in the pitching motion of the right arm was calculated for each time in the world coordinate system and the local rotating coordinate system. FIG. 21 shows a graph of the results in the world coordinate system. The maximum velocity Vmax in the world coordinate system was 16.21 m/sec. FIG. 22 shows a graph of the results of the velocity per time in the rotating coordinate system. In a relative comparison, the maximum velocity Vmax per time in the rotating coordinate system reached a value close to the Vmax of the world coordinate system of 16.21 m/sec, which was 16.03 m/sec (98.89% when the maximum velocity in the world coordinate system is 100%). From this, it can be determined that the pitching motion places a large load on the elbow.
23 shows the results of calculating the acceleration over time of the elbow in the world coordinate system and the local rotating coordinate system and comparing them relatively for the right arm during the pitching motion. The maximum acceleration in the rotating coordinate system exceeds the maximum acceleration in the world coordinate system, and it can be determined that this is a pitching motion that places a large load on the elbow, which is the joint in question.
24 shows the results of calculating and relatively comparing the displacement of the elbow in the world coordinate system and the local rotating coordinate system in relation to the elbow during the pitching motion of the right arm. The displacement of the elbow in the rotating coordinate system exceeds the displacement of the elbow in the world coordinate system, and it can be determined that this is a pitching motion that places a large load on the elbow, which is a joint part.

In the above embodiment, an example of pitching a baseball is shown. In the present invention, the movement involving a rotational motion with an acceleration of more than 9.8 m/sec ² refers to a movement involving a rotational motion with an acceleration of more than 9.8 m/sec ² in the world coordinate system. In the present invention, the movement involving a rotational motion with an acceleration of more than 9.8 m/sec ² includes any movement involving a rotational motion with an acceleration of more than 9.8 m/sec ^2. For example, the movement involving a rotational motion in sports using flying objects or sliding objects such as baseball, softball, soccer, tennis, golf, volleyball, basketball, cricket, hockey, rugby, American football, handball, water polo, bowling, lacrosse, table tennis, squash, badminton, ice hockey, etc., as well as any movement involving a rotational motion such as dance or figure skating, etc. are included. In addition, even if the movement involves a rotational motion with an acceleration of more than 9.8 m/sec ² , even if the movement involves a rotational motion in athletics, swimming, diving, gymnastics, acrobatics, exercise, etc., the movement involving a rotational motion of the present invention is included. Of course, any movement involving a rotational motion other than the above listed movements is included.

When pitching a baseball, the center of rotation of the body during the movement is somewhere on the spine, but in rotational movements in other sports, such as kicking a ball in soccer, the center of rotation is at the hip joint, etc. In this way, the center of rotation within the human body during movements involving rotational movements in this invention will differ depending on the type of movement, but the center of rotation within the human body can be defined according to the type of movement.

According to the present invention, in the above-mentioned various exercises involving rotational movements with an acceleration of 9.8 m/sec2 or ^more , the rotational coordinate system coordinate data of one's own rotational movement can be relatively compared with the world coordinate system data of one's own rotational movement, thereby visualizing and evaluating the physical load acting on the joints of the body, performance, etc.

10, 12: bones, 14: joints, 16: arbitrary object, 18: center, 20: rotational movement evaluation system, 22: memory unit, 24: information input operation unit, 26: control unit, 28: display unit, 30: server, 32: terminal device, 34: communication network, 36: input unit, 38: communication interface, 40: RAM/ROM, 42: CPU, 44: memory, 46: display interface.

Claims

A rotational movement exercise evaluation method for estimating and evaluating performance and/or physical load in an exercise involving a rotational movement with an acceleration exceeding 9.8 m/ sec2 ,
A rotation center definition process for defining a rotation center from at least one real rotation center obtained from a group of an actual movement, a rotation movement by skeletal estimation, and a motion capture, and/or an ideal rotation center;
obtaining world coordinate system coordinate data, which is coordinate data in the world coordinate system during the rotational motion from the defined rotation center;
A step of converting the world coordinate system coordinate data into rotating coordinate system local coordinate data, which is local coordinate data of a rotating coordinate system having a rotation center within the human body as an origin during the rotational motion;
an evaluation step of relatively comparing and evaluating two data values of the world coordinate system coordinate data and the rotating coordinate system local coordinate data of a predetermined position in the human body obtained from the same rotational motion;
A rotational motion assessment method comprising:
the world coordinate system coordinate data is world coordinate data indicating world coordinates of a predetermined position in a human body for each time period,
2. The rotational motion evaluation method according to claim 1, wherein the rotating coordinate system local coordinate data is local coordinate data indicating local coordinates of a predetermined position within the human body for each time period, the local coordinates being taken as an origin at a center of rotation within the human body during the rotational motion.
The method for evaluating rotational motion according to claim 1, wherein the evaluation step is a step of evaluating by relative comparison the speed or acceleration shown for each time at a predetermined position in the human body.
The evaluation is an evaluation of physical load,
The two pieces of data, the world coordinate system coordinate data and the rotation coordinate system local coordinate data, are data relating to a velocity or acceleration indicated for each time at a predetermined position in a human body,
4. The rotational motion assessment method according to claim 3, wherein the physical load is determined to be large when the maximum velocity or maximum acceleration of the rotating coordinate system local coordinate data is close to or greater than the maximum velocity or maximum acceleration of the world coordinate system coordinate data.
The evaluation is an evaluation of physical load,
the two pieces of data, the world coordinate system coordinate data and the rotating coordinate system local coordinate data, are data relating to an area of a velocity graph shown for each time at a predetermined position in the human body or data relating to a displacement of a predetermined position in the human body;
The area of a graph of the velocity of a predetermined position in the human body shown per time in the rotating coordinate system local coordinate data or the displacement of a predetermined position in the human body is
The area of a graph of the velocity of a predetermined position in the human body shown per time in the world coordinate system coordinate data or the displacement of a predetermined position in the human body,
2. The method of claim 1, wherein the physical load is determined to be large when the measured value is close to or greater than .
The method for evaluating rotational motion as described in claim 1, further comprising a step of evaluating the rotational center coincidence rate between the actual rotational center and the ideal rotational center in the rotational center definition step.
A method for converting coordinate data in a rotational movement, which is used in the rotational movement evaluation method according to claim 1,
In motion involving rotational motion with an acceleration exceeding 9.8 m/ sec2 ,
A rotation center definition process for defining a rotation center from at least one real rotation center obtained from a group of an actual movement, a rotation movement by skeletal estimation, and a motion capture, and/or an ideal rotation center;
obtaining world coordinate system coordinate data which is coordinate data of a world coordinate system indicating the world coordinates of a predetermined position in the human body during the rotational movement from the defined rotation center for each time;
defining a center coordinate of the world coordinate system coordinate data for each time;
A step of obtaining orthogonal coordinate system data by matching one axis of the orthogonal coordinate system with a line segment connecting the center coordinate and a predetermined joint position;
converting the orthogonal coordinate system data into local coordinate data that indicates local coordinates of a predetermined position within the human body for each time period, the local coordinates being defined by a center of rotation within the human body during the rotational motion as an origin;
A method for converting coordinate data in a rotational motion, comprising:
A rotational movement exercise evaluation system that estimates and evaluates performance and/or physical load in exercise involving rotational movements with acceleration exceeding 9.8 m/ sec2 ,
A rotation center definition device that defines a rotation center from at least one real rotation center obtained from a group of an actual movement, a rotation movement by skeletal estimation, and a motion capture, and/or an ideal rotation center;
a world coordinate system coordinate data acquisition device for acquiring world coordinate system coordinate data, which is coordinate data in the world coordinate system during the rotational movement from the defined rotation center;
a conversion device for converting the world coordinate system coordinate data into rotating coordinate system local coordinate data, which is local coordinate data of a rotating coordinate system having an origin at a rotation center within the human body during the rotational motion;
a relative comparison device for relatively comparing two data values of the world coordinate system coordinate data and the rotating coordinate system local coordinate data of a predetermined position in the human body obtained by the same rotational motion;
A rotational motion assessment system comprising:
the world coordinate system coordinate data is world coordinate data indicating world coordinates of a predetermined position in a human body for each time period,
9. The rotational motion motion evaluation system according to claim 8, wherein the rotating coordinate system local coordinate data is local coordinate data indicating local coordinates of a predetermined position within the human body for each time period, the local coordinates being taken as an origin at a center of rotation within the human body during the rotational motion.
The evaluation is an evaluation of physical load,
The two pieces of data, the world coordinate system coordinate data and the rotational coordinate system local coordinate data, are data relating to a velocity of a predetermined position in a human body for each time period,
9. The rotational motion exercise evaluation system according to claim 8, wherein the physical load is determined to be large when the velocity of the rotational coordinate system local coordinate data is close to or greater than the velocity of the world coordinate system coordinate data.
A conversion system for converting coordinate data in a rotational movement, which is used in the rotational movement evaluation system according to claim 8,
In motion involving rotational motion with an acceleration exceeding 9.8 m/ sec2 ,
A rotation center definition device that defines a rotation center from at least one real rotation center obtained from a group of an actual movement, a rotation movement by skeletal estimation, and a motion capture, and/or an ideal rotation center;
a world coordinate system coordinate data acquisition device for acquiring world coordinate system coordinate data, which is coordinate data of a world coordinate system indicating the world coordinates of a predetermined position in the human body during the rotational movement from the defined rotation center for each time;
a device for defining the center coordinates of the world coordinate system coordinate data for each time;
a device for obtaining orthogonal coordinate system data by matching one axis of an orthogonal coordinate system with a line segment connecting the center coordinate and a predetermined joint position;
and a conversion device that converts the Cartesian coordinate system data into local coordinate data that indicates, for each time period, local coordinates of a predetermined position within the human body during the rotational motion, with the center of rotation within the human body as the origin.
A program for causing a computer to function as each device in the rotational motion evaluation system described in claim 8.
A program for causing a computer to function as each device in a coordinate data conversion system for rotational motion as described in claim 11.