CN116348080A - Method for evaluating gait influence of absorbent article - Google Patents

Abstract

The present invention provides a method for evaluating the influence of gait on an absorbent article, which evaluates the extent of the influence of wearing of the absorbent article on gait, comprising the following steps (A) - (C). (A) A step of monitoring a normal gait by walking for at least 3 walking cycles while the person is not wearing the absorbent article to be evaluated; (B) A step of monitoring gait during wearing of the absorbent article to be evaluated by walking for at least 3 walking cycles; and (C) a comparison step of comparing the normal gait with the gait when worn.

Description

Method for evaluating gait influence of absorbent article

Technical Field

The present invention relates to a method for evaluating gait influence of an absorbent article.

Background

As one of various performances required of an absorbent article such as a disposable diaper, there is an ease of movement of a lower limb in a worn state, and an evaluation method thereof has also been proposed.

For example, the applicant has proposed a method for evaluating the ease of movement of the lower limb in a state where a pants-type diaper is worn, based on the degree of muscular load of the lower limb of the wearer when walking in the state where the diaper is worn (see patent document 1).

According to the method of patent document 1, the activity easiness of the lower limb of the wearer in the state of wearing the pants-type diaper can be objectively evaluated, for example, the activity easiness of the lower limb can be objectively evaluated even in the case where the wearer is an infant who is difficult to directly hear the opinion.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2011-15747

Disclosure of Invention

The invention provides a method for evaluating the gait influence of an absorbent article, which evaluates the extent of the influence of wearing of the absorbent article on gait.

The evaluation method of the present invention preferably includes the following steps (a) to (C).

(A) A step of monitoring a person by taking a normal gait at least 3 walking cycles without wearing an absorbent article to be evaluated;

(B) A step of monitoring by taking a picture of gait at the time of wearing at least 3 walking cycles in a state where an absorbent article to be evaluated is worn; and

(C) A comparison step of comparing the normal gait with the gait when worn.

In the step (C), it is preferable that information on gait, a parameter (gait parameter) indicating gait, obtained by analyzing or processing data obtained by the monitoring results in the step (a) and the step (B), be compared between a normal gait and a wearing-time gait. The term "analyze or process" also includes both analysis and processing.

In the comparison of gait in the step (C), all of the data of the 3 walking periods detected in the steps (a) and (B) may be omitted, and only the data of one walking period may be extracted and compared with the data of the one walking period.

The invention provides a method for evaluating gait influence of an absorbent article, which is used for comparing and evaluating the influence degree of wearing of the absorbent article on gait for at least 2 different absorbent articles.

The evaluation method of the present invention preferably includes the following steps (D) to (F).

(D) A step of monitoring a gait of wearing the absorbent article by taking a picture of the gait of the wearer while walking for at least 3 walking cycles;

(E) A step of monitoring a gait of wearing the absorbent article by taking a picture of the gait of the wearer while walking for at least 3 walking cycles; and

(F) A comparison step of comparing the wearing gait of the one absorbent article with the wearing gait of the other absorbent article.

In the step (F), it is preferable that the gait of the plurality of absorbent articles is compared based on information on gait obtained by analyzing or processing data obtained by the monitoring in the step (D) and the step (E) and a parameter (gait parameter) indicating gait. The term "analyze or process" also includes both analysis and processing.

In the comparison of gait in the step (F), all of the data of the 3 walking periods detected in the steps (D) and (E) may be omitted, and only the data of one walking period may be extracted and compared with the data of the one walking period.

Other features of the present invention will be apparent from the description of the scope of the claims and from the description below.

Drawings

Fig. 1 is an overhead view of a walk that shows a preferable example of a walk for monitoring gait.

Fig. 2 is a state of sensor wear for taking three-dimensional images in a method of analyzing a monitored gait.

Fig. 3 (a) and 3 (b) are explanatory diagrams of the coronal hip joint angle and the change in the coronal hip joint angle, and fig. 3 (c) is a graph showing the measurement result of the change in the coronal hip joint angle in walking for a child wearing a diaper and a child not wearing a diaper.

Fig. 4 (a) and 4 (b) are explanatory diagrams of changes in the pelvic angle and the pelvic angle, and fig. 4 (c) is a graph showing measurement results of changes in the pelvic angle during walking of a baby wearing a diaper and a baby not wearing a diaper.

Fig. 5 (a) and 5 (b) are explanatory views of the sagittal hip joint angle and the change in the sagittal hip joint angle, and fig. 5 (c) is a graph showing the measurement result of the change in the sagittal hip joint angle in walking for a baby wearing a diaper and a baby not wearing a diaper.

Fig. 6 (a) and 6 (b) are explanatory views of the body center of gravity and the left-right direction change of the body center of gravity, and fig. 6 (c) is a graph showing the measurement result of the total movement distance of the body center of gravity in the left-right direction in walking of a baby wearing a diaper and a baby not wearing a diaper.

Fig. 7 (a) is an explanatory view of the change in the vertical direction of the body center of gravity, and fig. 7 (b) is a movement distance in the extending direction of the body center of gravity during walking of a baby wearing a diaper and a baby not wearing the diaper.

Fig. 8 (a) is an explanatory diagram of the step distance, and fig. 8 (b) is a graph showing the measurement result of the step distance during walking of a baby wearing a diaper and a baby not wearing a diaper.

Fig. 9 (a) is a block diagram of the gait influence evaluation system, and fig. 9 (b) is a flowchart of evaluation based on the gait influence evaluation system.

Fig. 10 is a cross-sectional view of an absorber used in the diaper of test example 1 along the diaper width direction.

Fig. 11 is a graph showing the relationship between the coronal hip joint angle and the ratio of the pressure applied to the inner side of the leg.

Fig. 12 is a graph showing measurement results of coronal hip joint angle in evaluation I of gait influence.

Fig. 13 is a graph showing the measurement result of the total movement distance of the body center of gravity in the left-right direction in the evaluation I of the gait influence.

Fig. 14 is a graph showing the measurement result of the step pitch based on the bone information in the evaluation II of the gait influence.

Fig. 15 is a graph showing the measurement result of the interval between the knees in the evaluation II of the gait influence.

Detailed Description

The performance of absorbent articles is expected to be improved year by year, for example, diapers having more excellent ease of movement of lower limbs in a state where diapers are worn, or, when evaluating the ease of movement in a state where diapers are worn for a plurality of diapers, it is desired that small differences in gait occurring between the plurality of diapers can be detected, but there is room for improvement in the conventional evaluation methods in detecting small differences occurring between the plurality of diapers.

In patent document 1, there is no description about monitoring gait by measuring a change in myoelectric potential during walking with an electrode attached to a leg.

The present invention relates to a method for evaluating the influence of gait of an absorbent article, which can evaluate the influence of the absorbent article on human gait with high accuracy.

The present invention will be described below with reference to the drawings based on preferred embodiments.

In this specification, "measurement" is not limited to the acquisition of a value of data, but includes acquiring data, and calculating a predetermined parameter using the acquired value.

The method for evaluating an absorbent article according to the present invention is a method for evaluating the effect of an absorbent article such as a diaper on the gait of a wearer wearing the absorbent article. Gait is a state of a walker that can be visually captured, and is a dynamic feature such as a walking posture, an action, a joint movement mode, or a feature such as a stride (stride) or a step distance when the walker touches the ground. Gait is visually monitored by photographing the walker. The dynamic characteristics and the characteristics at the time of touchdown may be monitored either alone or in combination.

Absorbent articles to be evaluated widely include articles for absorbing liquid discharged from a human body. The absorbent article generally has a liquid-permeable front sheet, a liquid-impermeable or water-repellent leakage-preventing sheet, and a liquid-retentive absorbent member interposed between the two sheets. Examples of the absorbent article include, but are not limited to, disposable diapers, sanitary napkins, incontinence pads, and panty liners.

The absorbent article to be evaluated is preferably a disposable diaper. Disposable diapers include pant-type diapers and unfolding-type diapers. The pants-type diaper generally has an absorbent main body including a liquid-permeable front sheet, a liquid-impermeable or water-repellent leakage-preventing sheet, and a liquid-retaining absorbent body disposed between the two sheets, and is formed into pants by joining both side edges of one end portion and both side edges of the other end portion in the longitudinal direction of the absorbent main body. The developed diaper generally has an absorbent main body including a liquid-permeable front sheet, a liquid-impermeable or water-repellent leakage-preventing sheet, and a liquid-retaining absorbent body disposed between the two sheets, wherein a fastening tape is provided at both side edges of one end portion in the longitudinal direction of the absorbent main body, and a fastened region to which the fastening tape is fastened is provided at an outer surface of the other end portion.

The diaper to be evaluated may be a diaper for adults or a diaper for infants.

A preferred first embodiment of the present invention is a method for evaluating the degree of influence of wearing of an absorbent article on gait, the method being used for evaluating the degree of influence of gait of the absorbent article. The evaluation method according to the first embodiment includes the following steps (a) to (C). The order in which steps (A) and (B) are performed is not distinguished. For example, step (B) may be performed after step (a), or step (a) may be performed after step (B).

[ step (A) ]

Step (a) is a step of monitoring the gait by walking at least 3 walking cycles while the person is not wearing the absorbent article to be evaluated. The gait in a state where the absorbent article is not worn is referred to as a normal gait. The gait of a state in which the absorbent article is worn is referred to as a wearing gait. The "state without wearing an absorbent article" herein refers to a state in which the body is not in any way worn as bare body, or a state in which only underwear made of cloth, nonwoven fabric, or the like without an absorber is worn.

Hereinafter, a case where the absorbent article to be evaluated is a disposable diaper (hereinafter also referred to as a diaper) will be described as an example.

In step (a), a person is walked without wearing an absorbent article to be evaluated, and the walking state is monitored. The monitoring is preferably performed by photographing a person walking by a known imaging device. It is sufficient to monitor data necessary for obtaining walking information for comparison evaluation in order to obtain a later-described amount of change in hip joint angle, a pelvic rotation amount, a movement amount of the center of gravity, or the like. As described in this embodiment, when an imaging device is used, the imaging device may be a device that captures a moving image, or may be a device that captures a still image a plurality of times at appropriate intervals. In addition, a three-dimensional motion capture device (three-dimensional motion analysis device) that can take in the positions of marks provided at a plurality of parts of the body of the wearer at a predetermined time may be used. As the marker of the three-dimensional motion capture device (three-dimensional motion analysis device), a suitable marker may be selected and used according to the type of the device, and for example, a sheet-like or spherical member that reflects various light rays such as infrared rays may be used.

A particularly preferred imaging device is a Vicon imaging system, for example, a Vantage/Vero imaging system of Vicon can be used. The Vicon imaging system can measure the position information and movement information of the mark with high accuracy in real time, and process the information with motion capture software such as Nexus, shogun, tracker, polygon, pegasus, so that not only the imaging in step 2 can be performed, but also the measurement of the change of the wearer with time change in step 3 can be easily performed.

In step (a), gait of the walking person is monitored, and data of changes in the position of the mark generated in at least 3 walking cycles is acquired. By monitoring gait for 3 or more gait cycles, a more accurate evaluation can be achieved.

In step (a), the specific position of the body can be extracted from moving image data obtained by capturing the walking state of the walking person without marking the mark by using a known skeleton information acquisition technique, for example, openPose (url=https:// gthub.com/CMU-periodic-Computing-Lab/pos) or vision Pose (url=https:// www.next-system.com/vision). In the bone information acquisition technique, for example, a neck, a shoulder, an elbow, a wrist, a waist, a knee, an ankle, and the like are extracted, and the extracted portions are represented by points and lines to estimate the posture. In addition, the joint position can be determined by using bone information acquisition technology. By using the dynamic image data of the photographed gait and the bone information acquisition technique, the measurement of gait parameters and changes thereof for comparison of gait becomes easy.

[ step (B) ]

Step (B) is a step of walking at least 3 walking cycles in a state where the person wears the absorbent article to be evaluated, and monitoring the gait at the time of wearing. The monitoring is preferably performed by photographing a person walking by a known image pickup device.

From the standpoint of excluding the influence of the personal difference, it is preferable that the person walking in step (a) and the person walking in step (B) are substantially the same person, but the present invention is not limited thereto, and groups of a plurality of persons having similar attributes may be compared with each other, and the present invention is not necessarily limited to the same person.

In step (B), the diaper to be evaluated is preferably worn on a person who assumes the age of wearing the diaper. For example, the wearer in the case of a diaper for an adult is an adult, and the wearer in the case of a diaper for an infant is an infant. However, in order to evaluate the influence on the walking of the wearer, the wearer in the case of evaluating the pants-type diaper for infants is limited to infants of a walking-enabled age. The term "age" as used herein includes month-old ones.

Since the walking ability of infants varies greatly from the time when the hand can stand to the time when the hand can freely walk back and forth, and since the influence of the diaper on walking also varies in the time when the walking ability rapidly progresses, it is useful to investigate the influence of the diaper on the walking of the wearer for infants in this time, and to develop diapers suitable for each stage of development. From this point of view, the wearer wearing the garment preferably has a month-old period of 12 months to 30 months.

The diaper to be worn by the wearer as the evaluation target may be a diaper in a dry state in which the liquid assumed by urine or the like is not absorbed, or may be a diaper in a wet state in which the liquid assumed by urine or the like is absorbed. As the liquid such as urine, water and physiological saline are preferably used.

Comparing the case of wearing a diaper in a dry state with the case of wearing a diaper in a wet state, whether or not the diaper in a dry state and the diaper in a wet state have a difference in influence on the gait of the diaper can be examined.

[ step C ]

Step (C) is a step of comparing the normal gait with the gait when worn.

In step (C), based on the data obtained as a result of the monitoring in step (a) and step (B), walking information is obtained for the normal gait and the gait at the time of wearing, respectively, by a method of analyzing the gait. The data obtained as a result of the monitoring is, for example, position information or movement information of a marker obtained by the Vicon imaging system.

The method of analyzing gait is preferably three-dimensional image analysis. Positional information on walking body type, bones, joints, and the like is obtained by using three-dimensional image analysis, and time-series motion information of moving images or a plurality of still images taken continuously is obtained by analyzing them. As a method of three-dimensional image analysis, there can be exemplified: a mode of constructing a shooting space by utilizing a plurality of cameras and tracking the position of the reflective mark, namely an optical method; an inertial sensor method for calculating a position and a posture from information of inverse motion of an inertial sensor composed of a gyro sensor (angular velocity meter) and an accelerometer; mechanical methods using sensors for measuring rotation angle and displacement such as positioners and encoders; a magnetic method in which a magnetic field is transmitted to a shooting range by using a magnetic field generating device and received by a magnetic sensor to be worn, and the like. Among these, from the viewpoint of high absolute positional accuracy, an optical motion capture system such as a Vantage/Vero imaging system of Vicon is preferably used. A method of extracting the three-dimensional coordinates (kinect) of the feature point from the moving image without the mark may be used.

The method for analyzing gait is preferably a method for calculating three-dimensional image coordinates from two-dimensional dynamic image coordinates from the viewpoint of being less limited in equipment and being able to monitor more daily gait. As a method for obtaining three-dimensional image coordinates from a two-dimensional moving image, there is a technique for estimating three-dimensional coordinates from a two-dimensional image using deep learning and a neural network. In either case, three-dimensional coordinates are constructed by inference of two-dimensional skeleton point coordinates by openelse or the like. Among these methods, there are supervised learning and unsupervised learning, but from the viewpoint of accuracy, a gait analysis method constructed from three-dimensional coordinates based on two-dimensional skeleton point coordinates of the supervised learning is preferable.

The comparison of the gait in the step (C) is preferably performed using information indicating the gait and gait parameters indicating the gait. The gait parameters preferably include any one or more of (1) a coronal hip joint angle, (2) a pelvic angle, (3) a sagittal hip joint angle, (4) a movement amount of the body center of gravity, (5) a stride, and (6) a distance between both knees, and in step (C), the normal gait and the gait at the time of wearing are preferably compared with each other based on a change in the coronal hip joint angle, a change in the pelvic angle, a change in the sagittal hip joint angle, or a movement amount of the body center of gravity, as a change in the wearer with a time change.

(1) Variation of coronal hip joint angle

The measurement of the change in the coronal hip angle and the evaluation based on the measurement result thereof will be described.

As shown in fig. 3 (a) and 3 (b), the coronal hip joint angle is an index mainly indicating the movement amount of the thigh section to the side of the pelvis. For example, when an XYZ coordinate system of the pelvis [ refer to fig. 4 (a), hereinafter also referred to as a pelvic coordinate system ] and an XYZ coordinate system of the thigh [ refer to fig. 3 (a), hereinafter also referred to as a thigh coordinate system ] are assumed, an inclination angle of an X-Z plane or an X-Y plane of the pelvic coordinate system with respect to an X-axis or a Z-axis of the thigh coordinate system rotated about a Y axis of the pelvic coordinate system, or the like is measured as the coronal hip joint angle. The Z-axis of the thigh coordinate system is assumed to be on a straight line connecting the hip joint center P1 and the knee joint center P2. Regarding the hip joint center P1 and the knee joint center P2, for example, the hip joint center P1 can be calculated from the positions of the greater trochanter M1 and the pelvis, and the position of the knee joint center P2 can be calculated as the midpoint of the outer knee M2 and the inner knee M3. The position of the pelvis is constituted by the sacrum P5 and the left and right anterior superior iliac spines P3, P4 [ refer to fig. 4 (a) ]. The Y axis of the thigh coordinate system is assumed to be a straight line passing through the hip joint center P1 and perpendicular to a plane passing through 3 points of the hip joint center P1, the knee joint center P2, and the greater trochanter M1, and the X axis of the thigh coordinate system is assumed to be a straight line passing through the hip joint center P1 and perpendicular to the Y and Z axes of the thigh coordinate system. Each of the portions of the hip joint center P1, the knee joint center P2, and the like is obtained by using known analysis software such as Visual3D based on a portion detected by a motion capture device or the like, for example.

In the step of monitoring gait, by monitoring gait of the wearer for 3 or more walking cycles, for example, data of the change in the position of the mark generated in 3 walking cycles can be obtained, and therefore, using these data, the change in the hip joint angle generated in one walking cycle as shown in fig. 3 (c) can be measured.

As shown in the present embodiment, in terms of the hip joint angle (coronal hip joint angle, sagittal hip joint angle), it is preferable to measure or analyze the displacement of the hip joint, thigh joint, or the like from the relation with the coordinate system set in the pelvis, from the viewpoint of more accurately comparing gait. The method of measuring the coronal hip joint angle is not limited to the above method. The same applies to the sagittal hip joint angle described later.

Fig. 3 (c) is a graph showing the hip joint angle change of the number of one walking cycle generated when the walker 3 shown in fig. 3 is walked without teaching the speed or the stride for 26 infants who can walk on their own with the age of 18 to 20 months who wear only the pants-type diapers 1 to 3, together with the result of walking in the same manner as in the bare state without wearing the diapers.

Diapers 1 and 2 are the same structure, diaper 3 is different from diapers 1 and 2, diapers 1 and 3 are wet states in which 160g of physiological saline is absorbed, and diaper 2 is a dry state diaper. The dry state is a state before absorption of physiological saline water. Around the walkway 3 shown in fig. 1, a plurality of Vicon31 are arranged as three-dimensional motion capturing devices. Reference numeral 32 indicates a device for measuring the force received from the ground, a force measuring plate (AMTI, 2000 Hz) being used.

The following table 1 shows the structures of diapers 1, 2, and 3. In table 1, the meaning of the absorbent core, the central region, the side regions, the pair of curved guides, and the other curved guides is the same as that of the diaper 4 described in the test example described later (see fig. 10). In tables 1 and 3, the dimensions of each portion of the absorbent core are values in the dry state.

TABLE 1

[ measurement of pressure applied to the inner side of the leg ]

The values of the pressure applied from both side portions of the crotch portion of the diaper to the inner sides of the legs were measured for the diaper 2 in the dry state and the diapers 1 and 3 in the wet state by the following methods. In table 2, the ratio of the pressure applied to the inner side of the leg (kPa) to the pressure applied to the diaper 2 in the dry state (kPa) is shown as a reference value 1 for each diaper.

[ method of measuring pressure applied to the inner side of leg ]

The diaper was put on a lower limb movable baby model, and the pressure applied to the inner sides of the left and right legs by the diaper when the left and right legs at the position where the left and right spacing between the legs is narrowest were staggered during walking was measured by a contact pressure gauge (AMI Techno co., ltd., "AMI 3037").

TABLE 2

As shown in fig. 3 b, the value of the coronal hip angle (°) decreases when the knee center P2 is abducted (abducted) at the hip joint moving to the outside in the lateral direction of the wearer, and increases when the knee center P2 is adducted (adducted) at the hip joint moving to the inside in the lateral direction of the wearer. In fig. 3 (c), the difference in walking distance between each of the walking cycles based on the difference in diapers is ignored, and the walking distance in the X-axis direction corresponding to the amount of one walking cycle is represented as the same. In the graph of fig. 3 (b), the average value of the values of the coronal hip joint angle of the right foot and the coronal hip joint angle of the left foot is 1/2 of the total value of the values at the same position from the start of one walking cycle. Regarding the change in the amount of one walking cycle of each of the right foot and the left foot, the amount of 3 walking cycles was measured for at least one foot, and the average value of the values at the same ratio from the start of one walking cycle was averaged as the change in the amount of one cycle of each foot.

As shown in fig. 3 (c), walking with the diapers 1 to 3 on is hip abducted walking relative to walking in a bare state. Since the bare state is the state in which the diaper has the least influence on the walking of the wearer, the influence of the diapers 1 to 3 on the walking of the wearer can be evaluated by comparing the changes in the hip joint angles of the walking in the state in which the diapers 1 to 3 are worn and the walking in the bare state.

In order to reduce the influence of the absorbent article on walking, it is preferable that the change in hip joint angle is not different or is small in a normal gait and a gait when worn.

For example, the integral value of the entire or a part of the region of the chart of the coronal hip joint angle change in one gait cycle is calculated, and when the integral value is compared with the gait at the time of wearing, the integral value at the time of ordinary gait is larger than the integral value at the time of wearing, but it is preferable that the difference is smaller. The integral value is, for example, an area of a region surrounded by a straight line having an angle of zero and a curve of 1 whole walking cycle in fig. 3 (c), and from the viewpoint of obtaining an absorbent article having a small degree of influence of gait, a difference between the integral value at normal gait and the integral value at wearing gait, that is, (integral value at normal gait) - (integral value at wearing gait) is preferably 0 to 5, more preferably 0 to 4. In this case, the area lower than the straight line with the angle of zero, that is, the negative area is calculated as a negative value.

In addition, it is preferable to compare the maximum or minimum value of the coronal hip joint angle for one walking cycle with the normal gait and the gait when worn. The coronal hip joint angle here is an angle in which the angle on the adduction side is positive and the angle on the abduction side is negative, as shown in fig. 3 (c). At the maximum value of the coronal hip angle, the value at gait is usually larger than the value at gait when worn, but the difference is preferably small. At the minimum value of the hip angle, the value at normal gait is greater than the value at gait when worn, but the difference is preferably small.

From the viewpoint of forming an absorbent article having a small degree of influence of gait, the difference between the maximum value of the coronal hip joint angle at normal gait and the maximum value of the coronal hip joint angle at wearing gait, that is, (maximum value at normal gait) - (maximum value at wearing gait) is 0 or more and 2 or less, more preferably 0 or more and 1.6 or less.

The difference between the minimum value of the coronal hip angle at normal gait and the minimum value of the coronal hip angle at wearing gait, that is, (the minimum value at normal gait) - (the minimum value at wearing gait) is preferably 0 or more and 2 or less, more preferably 0 or more and 1.6 or less.

It is preferable that the value of the coronal hip joint angle at a predetermined point in the swing phase of one walking cycle is compared with the normal gait and the wearing gait. The coronal hip joint angle here is an angle in which the angle of the adduction side is positive and the angle of the supination side is negative, as shown in fig. 3 (c). For example, the value of the coronal hip angle at a position of a walking distance of 80% of one walking cycle at a predetermined point in the step period of the coronal hip angle can be used as a parameter concerning gait.

Fig. 11 graphically illustrates the relationship between the value of the coronal hip joint angle at a position of 80% of the walking distance in one walking cycle and the ratio of the pressure applied to the inner side of the leg at a predetermined point in the walking phase of the coronal hip joint angle in the non-worn state (nude) and the worn state of the diapers 1 to 3.

As shown in the graph of fig. 11, as a parameter concerning gait, when the coronal hip joint angle at 80% is used, there is a correlation between the evaluation result of the evaluation method based on the degree of gait influence and the magnitude of the pressure applied to the inner side of the leg by the diaper. Thus, the gait influence degree of the gait influence degree can be quantified based on the information of the correlation. The evaluation result of the method for evaluating the degree of gait influence according to the present invention varies according to the performance of the diaper, such as the walking easiness, and therefore the degree of influence on gait can be quantified.

In this way, when comparing the normal gait with the wearing gait, the value of the coronal hip joint angle at the predetermined point in the swing period is larger than the value of the wearing gait, but the difference is preferably small.

From the viewpoint of forming an absorbent article with a small degree of gait influence, the value of the coronal hip joint angle at a predetermined point in the swing period, for example, at a position of 80% of the walking distance in one walking cycle, that is (coronal hip joint angle at a position of 80% of the walking distance in normal gait) - (coronal hip joint angle at a position of 80% of the walking distance in wearing gait) is preferably 0 to 3, more preferably 0 to 2.5.

A preferred second embodiment of the present invention is a method for evaluating gait impact of an absorbent article by comparing and evaluating at least 2 different absorbent articles, comprising the following steps (D) to (F).

(D) A step of monitoring walking for at least 3 walking cycles while wearing one absorbent article by capturing a gait during wearing;

(E) A step of monitoring a gait of walking for at least 3 walking cycles while wearing another absorbent article;

(F) Comparing the gait of the one absorbent article when worn with the gait of the other absorbent article when worn.

Steps (D) and (E) of the second embodiment can be performed in the same manner as step (B) of the first embodiment. Step (F) of the second embodiment can be performed in the same manner as step (C) of the second embodiment. In the second embodiment, the order in which steps (D) and (E) are performed is not distinguished. For example, step (E) may be performed after step (D), or step (D) may be performed after step (E). From the standpoint of excluding the influence of personal differences, it is preferable to make the person walking in step (D) and the person walking in step (E) substantially the same person, but this is not a limitation, and groups of persons having similar attributes may be compared with each other, and thus the present invention is not necessarily limited to the same person. In addition, 2 different absorbent articles may be absorbent articles having a difference in state such as a wet state and a dry state, in addition to a difference in structure.

By wearing different absorbent articles in step (D) and step (E) and comparing walking information obtained by monitoring the gait of each wearing, the magnitude of the effect of wearing on the gait of a person can be compared for different 2 absorbent articles.

For example, although the diaper 1 and the diaper 2 shown in fig. 3 (c) have the same structure, since one diaper 1 in a wet state and the other diaper 2 in a dry state have a high tendency to be stretched out as compared with the diaper 2 in a dry state, it can be evaluated that the diaper 1 in a wet state has a large influence on the walking of the wearer as compared with the diaper 2 in a dry state. Further, since the diaper 3 tends to be stretched out more than the diaper 1 even in the wet state, it can be evaluated that the wet diaper 3 has a larger influence on the walking of the wearer than the diaper 1 even in the wet state.

In the step (B), the step (D), the step (E), and the like, it is preferable to perform an acclimation (training) step after the person wears the absorbent article and before the person walks to monitor the gait when the person monitors the gait during wearing. The domestication step is a step of adapting the absorbent article to the body shape of the person, and as the domestication treatment, for example, after the person wears a certain absorbent article, the person walks for 3 minutes or longer, and it is preferable to perform the domestication treatment every time the absorbent article is replaced.

A comparison of a normal gait with a wearing gait based on walking information or gait parameters, or a comparison of wearing gaits between different absorbent articles will be further described.

(2) Changes in pelvic angle

A measurement based on a change in the pelvic angle and evaluation of the measurement result thereof will be described.

As shown in fig. 4 (a) and 4 (b), the pelvic angle is defined as a relative angle to the laboratory coordinate system (X-Y plane) by the X-axis or Y-axis of the coordinate system of the pelvic plane P rotating around the Z-axis when, for example, the plane passing through the 3 points of the left and right anterior superior iliac spines P3, P4 and the sacrum P5 is set as the pelvic plane P.

The change in the pelvic angle can be exemplified: rotation about the X-axis, with the sacrum P5 side in the pelvic plane P displaced in the up-down direction, relative to the X-axis passing through the left and right anterior superior iliac spines P3, P4; a rotation about a Z axis, which is moved in one direction toward the front side of the wearer and in the other direction toward the rear side of the wearer, with respect to the Z axis passing through the center position between the left and right anterior-superior iliac spines P3, P4 and perpendicular to the pelvic plane P; rotation about the Y axis, in which one of the left and right anterior superior iliac spines P3, P4 is displaced upward in the vertical direction and the other is displaced downward in the vertical direction, with respect to the Y axis orthogonal to the X axis and the Z axis; and a compound rotation of 2 or more of these rotations.

The positions of the anterior superior iliac spines P3, P4 and the position of the sacrum P5 can be calculated from the position information of the marks provided in correspondence with each other, and the change in the pelvic angle generated in one walking cycle, for example, the above-described rotation about the X-axis, Y-axis or Z-axis pelvic plane can be obtained from the measurement of the position information of the marks provided in correspondence with the positions of the anterior superior iliac spines P3, P4 and the position of the sacrum P5 and the movement thereof.

Fig. 4 (c) is a graph showing the change of the pelvic angle, more specifically, the rotation about the Z-axis (rotation of the pelvis), of the individual walking cycle amount generated when the individual walking in the walk 3 shown in fig. 3 without giving the individual walking speed or the individual walking steps to the individual infants with 18 to 20 months of the month age of wearing the pants-type diapers 1 to 3, together with the result of the individual walking in the same manner without wearing the diaper in the bare state. The diapers 1 to 3 were the same as the diapers 1 to 3 in that they were in a wet state or a dry state in which 160g of physiological saline was absorbed. The graph shown in fig. 4 (c) shows the average value of the rotation angle with respect to the right foot and the rotation angle with respect to the left foot, with respect to one walking cycle of the right foot, the rotation around the Z axis in which the front upper iliac spine P3 on the right side of the wearer moves rearward being referred to as outward rotation, and with respect to one walking cycle of the left foot, the rotation around the Z axis in which the front upper iliac spine P4 on the left side of the wearer moves rearward being referred to as outward rotation.

As shown in fig. 4 (c), the rotation angle in the outward direction increases when walking in the state where diapers 1 to 3 are worn relative to walking in the bare state. Since the bare state is the state in which the diaper has the least influence on the walking of the wearer, the influence of the diapers 1 to 3 on the walking of the wearer can be evaluated by comparing the magnitudes of the rotation angles of the pelvis in the outward direction with respect to the walking of the diapers 1 to 3 in the bare state. The degree of rotation in the outward direction of walking on the diapers 1 to 3 is greater than that in the bare body, and it is presumed that the pelvis is rotated more than in the bare body because the difficulty of swinging the feet forward is dealt with in order to avoid the bulge of the diaper.

In addition, the diaper 1 and the diaper 2 have the same structure, but one is in a wet state and the other is in a dry state, and the diaper 1 in the wet state rotates in the outward direction to a greater extent than the diaper 2 in the dry state, so that it can be evaluated that the diaper 1 in the wet state has a greater influence on the walking of the wearer than the diaper 2 in the dry state. Further, even in the wet state, since the diaper 3 has a higher tendency to spin outward than the diaper 1, it can be evaluated that the diaper 3 has a larger influence on the walking of the wearer than the diaper 1.

In order to form an absorbent article that does not affect walking, it is preferable that there is no difference or a small difference in the change in the pelvic angle between a normal gait and a gait when worn.

For example, the integral value of the entire or a part of the region of one walking cycle in the map of the pelvic angle change in one walking cycle is calculated, and when the integral value is compared with the gait at the time of wearing, the integral value at the time of normal gait is smaller than the integral value at the time of wearing, but the smaller the difference is, the better. The integral value is, for example, the area of the region surrounded by the straight line having the angle of zero and the curve of the amount of 1 walking cycle in fig. 4 (c), and from the viewpoint of constituting the absorbent article having a small gait influence, the difference between the integral value at normal gait and the integral value at wearing gait, that is, the difference between (the integral value at normal gait) and the integral value at wearing gait is preferably-450 or more and 0 or less, more preferably-400 or more and 0 or less. At this time, a negative region lower than the straight line where the angle is zero, that is, a negative region is calculated as a negative value.

It is preferable that the differential value in a predetermined region of the map of the pelvic angle change in one walking cycle is compared between the normal gait and the wearing gait. From the viewpoint of forming an absorbent article having a small effect of gait, the value at normal gait is preferably smaller than the value at gait when worn in the first half 0 to 50% of one walking cycle, but the difference is preferably smaller, and the value at normal gait is larger than the value at gait when worn in the second half 050 to 100% of one walking cycle, but the difference is preferably smaller. From the viewpoint of constituting an absorbent article having a small degree of influence of gait, the ratio of the maximum value of the differential value at normal gait in the first half 0 to 50% of one walking cycle to the maximum value of the differential value at wearing gait, or the ratio of the minimum value of the differential value at normal gait to the minimum value of the differential value at wearing gait in the second half 050 to 100% of one walking cycle, that is, (differential value at wearing gait)/(differential value at normal gait) is preferably 1 to 1.5, more preferably 1 to 1.3. The differential value normalizes 1 walking cycle to 101 points, and the ratio of the change per 1 point is calculated.

Further, it is preferable to compare the normal gait with the gait at the time of wearing, with the value of the pelvic angle at a predetermined point in one walking cycle. As shown in fig. 4 (c), the pelvic angle is an angle in which the angle of the supination side is positive and the angle of the pronation side is negative. When comparing the value of the pelvic angle at a predetermined point in one walking cycle with the normal gait when worn, the value at normal gait is smaller than the value at worn gait, but the difference is preferably smaller.

From the viewpoint of forming an absorbent article having a small effect on gait, the value of the pelvic angle at a predetermined point in one walking cycle, for example, at a position of 50% of the walking distance in one walking cycle, that is (the pelvic angle at a position of 50% of the walking distance in normal gait) - (the pelvic angle at a position of 50% of the walking distance in wearing gait) is preferably-10 or more and 0 or less, more preferably-7 or more and 0 or less.

(3) Sagittal hip joint angle change

The measurement of the change in the sagittal hip angle and the evaluation based on the measurement result thereof are explained.

The sagittal hip joint angle is an angle that changes by rotating the thigh section around the X-axis of the coordinate system of the pelvis as shown in fig. 5 (a) and 5 (b) [ see fig. 4 (a) ]. For example, the angle of flexion increases and the angle of extension decreases as measured by the angle of inclination of the Z axis of the thigh with respect to the X-Z plane of the pelvis.

As shown in fig. 5 (c), the sagittal hip joint angle tends to be lower when walking with the diapers 1 to 3 on than when walking in a bare state. Since the bare state is the state in which the diaper has the least influence on the walking of the wearer, the influence of the diapers 1 to 3 on the walking of the wearer can be evaluated by comparing the magnitudes of the sagittal hip joint angles with the walking of the bare state in the state in which the diapers 1 to 3 are worn. The sagittal hip joint angle of the foot on which the diapers 1 to 3 were worn was smaller than that of the bare body, indicating that the diapers 1 to 3 had an effect on gait.

In order to form an absorbent article having little effect on walking, it is preferable that there is no difference or a small difference in sagittal hip joint angle between a normal gait and a gait when worn.

For example, the integral value of the whole or a part of the walking cycle in the chart of the sagittal hip joint angle of one walking cycle is calculated, and when the integral value is compared with the gait at the time of wearing, the integral value at the time of ordinary gait is smaller than the integral value at the time of wearing, and preferably the smaller the difference is, the better. The integrated value is, for example, the area of the region surrounded by a straight line having an angle of minus 10 degrees and a curve of the second half of 1 walking cycle in fig. 5 (c), and from the viewpoint of constituting an absorbent article having a small gait influence, the difference between the integrated value at normal gait and the integrated value at wearing gait, that is, (the integrated value at normal gait) - (the integrated value at wearing gait) is preferably 0 to 700, more preferably 0 to 650. At this time, a negative region lower than the straight line where the angle is zero, that is, a negative region is calculated as a negative value.

It is preferable that the change in the sagittal hip joint angle in one walking cycle, that is, the difference between the maximum value and the minimum value, is compared with the gait at the time of wearing. When comparing the maximum value and the minimum value with each other in the normal gait and the wearing gait, it is preferable that the difference in the normal gait is larger than the difference in the wearing gait, and the smaller the difference is, the better. From the viewpoint of the absorbent article having a small gait influence, the difference between the change amount of the sagittal hip joint angle in one walking cycle and the change amount in normal gait (the integral value in normal gait) - (the integral value in wearing gait), which is the difference between the change amount in normal gait and the change amount in wearing gait, is preferably-300 or more and 5 or less, and more preferably-200 or more and 0 or less.

(4) Movement of body center of gravity

The measurement of the movement amount of the body center of gravity and the evaluation based on the measurement result thereof will be described.

The body center of gravity is the center of gravity P6 of the wearer's body, and in the upright state of the wearer, as shown in fig. 6 (a), is located near the widthwise central portion at approximately the same position as the position of the pelvis, but the position swings left and right when walking. In a preferred method for measuring the amount of movement of the body's center of gravity, as shown in fig. 6 (a), the center of gravity of the entire body is calculated taking into consideration the center of gravity of the head calculated from the marker position provided on the head, the center of gravity of the upper limb calculated from the marker position provided on the upper limb, the center of gravity of the pelvis calculated from the marker position provided on the pelvis, and the center of gravity of the lower limb calculated from the marker position provided on the lower limb. Methods for calculating the position of the center of gravity of the body are known, and can be obtained by using the Visual3D function of motion capture software, for example.

As the movement amount of the body center of gravity, it is preferable to measure the total movement distance in the left-right direction, which is an integral value of the body center of gravity in the left-right direction (X direction) in one walking cycle. The left-right direction (X direction) is a direction intersecting the traveling direction (Y direction) of the wearer in a plan view of the walk. The total moving distance of the body center of gravity in the left-right direction without shaking at all is zero.

Fig. 6 (c) is a graph showing the total distance of movement of the center of gravity in the left-right direction of one walking cycle amount generated when the infant who wears the pants-type diapers 1 to 3 and walks on the walking path 3 shown in fig. 1 without teaching the speed and the stride for the infant who can walk on himself/herself for 18 to 20 months of the month of the wearing, together with the result of the same walking without wearing the diaper. The diapers 1 to 3 were similar to the diapers 1 to 3 in that they had been wet or dry with 160g of physiological saline absorbed. The graph shown in fig. 6 (c) represents an average value of the total movement distance of each walking cycle of the right foot and the total movement distance of each walking cycle of the left foot.

In fig. 6 (c), the average value and standard deviation of the total movement distance of 26 infants are shown. In fig. 7, "indicates that there is a significant difference in p-value <0.01 between the diaper or the diaper and the bare state (significant difference), and" "indicates that there is a significant difference in p-value <0.05 between the diaper or the diaper and the bare state.

As shown in fig. 6 (c), walking with the diapers 1 to 3 put on has a larger total distance of movement in the left-right direction of the center of gravity than walking in the bare state. Since the bare state is the state where the diaper has the least influence on the walking of the wearer, the influence of the diapers 1 to 3 on the walking of the wearer can be evaluated by comparing the length of the total movement distance in the left-right direction of the center of gravity between the walking of the diaper 1 to 3 and the walking of the bare state. The total distance of movement of the center of gravity in the lateral direction in walking with the diapers 1 to 3 is longer than in the bare state, which means that the influence on walking with the diapers 1 to 3 is larger and walking is less likely than in the bare state. The diaper 1 has the same structure as the diaper 2, but one is in a wet state and the other is in a dry state, and the total distance of movement of the center of gravity in the lateral direction is longer in the wet state than in the dry state of the diaper 2, so that the wet state of the diaper 1 has a larger influence on the walking of the wearer than in the dry state of the diaper 2, and can be evaluated as being difficult to walk. Further, even in the wet state, the total distance of movement of the center of gravity of the diaper 3 in the lateral direction is longer than that of the diaper 1, and therefore, the influence of the diaper 3 on the walking of the wearer is larger than that of the diaper 1, and it can be evaluated that walking is difficult.

In order to construct an absorbent article having little influence on walking, it is preferable that the movement amount of the body center of gravity is not different or is small in a normal gait and a gait at the time of wearing.

For example, when comparing a normal gait with a wearing gait, the total movement distance in the left-right direction of the body center of gravity in one walking cycle is smaller in the normal gait value than in the wearing gait value, but it is preferable that the smaller the difference is, the better. From the viewpoint of constituting an absorbent article having a small effect of gait, the difference between the total movement distance in the lateral direction of the body center of gravity in one walking cycle and the total movement distance in the lateral direction of the body center of gravity in the normal gait when worn, that is, (the total movement distance in the lateral direction of the body center of gravity in the normal gait) - (the total movement distance in the lateral direction of the body center of gravity in the worn) is preferably-0.020 or more and 0 or less, more preferably-0.012 or more and 0 or less.

As shown in fig. 6, the difference between the maximum value and the minimum value, which is the movement distance of the body center of gravity in the vertical direction, can be applied as walking information. In order to form an absorbent article having a small effect of gait, it is preferable that the distance of movement in the vertical direction of the body center of gravity is not or little different between a normal gait and a gait when worn.

For example, when comparing a normal gait with a wearing gait, it is preferable that the maximum value or the minimum value of the movement distance in the vertical direction of the body center of gravity in one walking cycle or 1/2 walking cycle is smaller if the value in the normal gait is larger than the value in the wearing gait.

From the viewpoint of constituting an absorbent article having a small effect of gait, the difference between the total movement distance in the vertical direction of the body center of gravity in normal gait and the total movement distance in the vertical direction of the body center of gravity in wearing gait, that is, (the total movement distance in the vertical direction of the body center of gravity in normal gait) - (the total movement distance in the vertical direction of the body center of gravity in wearing gait) is preferably 0 or more and 0.015 or less, more preferably 0 or more and 0.010 or less.

It is also preferable that the maximum value or the minimum value of the movement distance of the body center of gravity in the vertical direction in one walking cycle be compared with the gait at the time of wearing. When comparing the maximum value with the normal gait and the wearing gait, it is preferable that the difference is smaller if the maximum value at the normal gait is larger than the maximum value at the wearing gait. From the viewpoint of forming an absorbent article having a small effect of gait, the difference between the maximum value and the minimum value of the movement distance in the vertical direction of the body center of gravity in one walking cycle or 1/2 walking cycle, that is, the difference between the maximum value at normal gait and the maximum value at wearing gait (the maximum value at normal gait) - (the maximum value at wearing gait), is preferably 0 or more and 0.003 or less, more preferably 0 or more and 0.002 or less.

In addition, when comparing the normal gait with the wearing gait, it is preferable that the minimum value of the movement distance in the vertical direction of the body center of gravity in one walking cycle is smaller than the minimum value in the wearing gait, and the smaller the difference is, the better. From the viewpoint of forming an absorbent article having a small degree of gait influence, the difference between the maximum value and the minimum value of the movement distance in the vertical direction of the body center of gravity in one walking cycle or 1/2 walking cycle, that is, the difference between the maximum value at normal gait and the maximum value at wearing gait (the maximum value at normal gait) - (the maximum value at wearing gait), is preferably-0.001 or more and 0 or less, and more preferably-0.0005 or more and 0 or less.

According to the method for evaluating an absorbent article of the first and second embodiments, as a change in a wearer, a change in a hip joint angle (coronal hip joint angle, sagittal hip joint angle), a change in a pelvic angle, or a movement amount of the body center of gravity is measured, and based on the measurement result, the influence of the absorbent article on the walking of the wearer is evaluated, so that, as described above, the influence of the diaper on the walking can be evaluated as compared with the case of walking on bare ground, and, in addition, the influence of the diaper on the walking can be evaluated with high accuracy, for example, a difference in walking easiness, which cannot clearly show a difference in the method of the related art, can be objectively expressed. Further, since the evaluation can be performed objectively without directly inquiring the wearer, subjective knowledge of the wearer can be eliminated, and the evaluation of walking easiness, walking difficulty, and the like can be performed in an objective flow with high accuracy, regardless of whether the diaper is for infants or for adults.

The present invention has been described above based on preferred embodiments thereof, but the present invention is not limited to the above embodiments and can be appropriately modified.

For example, in the step of evaluating (step (C)), as a change of the wearer with time change, (1) a change of the coronal hip joint angle, (2) a change of the pelvic angle, (3) a sagittal hip joint angle, and (4) 2 or more of the movement amount of the body center of gravity may be measured, and the influence of the diaper on the walking of the wearer may be evaluated based on the measurement results of the plurality of indexes.

Alternatively, instead of this, the walking of the wearer wearing the diaper may be captured, and the walking pitch of the wearer may be measured. The pitch is the distance along the X direction between a straight line connecting the ground contact positions of the heels of one foot in series in the traveling direction (Y direction) at the time of walking and a straight line connecting the ground contact positions of the heels of the other foot in series in the traveling direction (Y direction) at the time of walking.

Fig. 7 is a graph showing a value of a step distance calculated by taking a photograph of 26 infants wearing pants-type diapers, that is, diapers 1 to 3, who can walk on their own for 18 to 20 months of the month, without teaching the infant to walk on the walker 3 shown in fig. 1 in terms of speed and step.

As for the step distance, the step distance becomes larger in the walking state in which the diapers 1 to 3 are worn than in the bare state. Since the bare state is the state in which the diaper has the least influence on the walking of the wearer, the influence of the diapers 1 to 3 on the walking of the wearer can be evaluated by comparing the walking pitch between the walking in the state in which the diapers 1 to 3 are worn and the walking in the bare state. The step length of walking with the diapers 1 to 3 is longer than in the bare state, which means that the effect on walking is greater with the diapers 1 to 3 than in the bare state, and walking is not easy. In addition, although the diaper 1 has the same structure as the diaper 2, when one of the diapers 1 is in a wet state and the other is in a dry state, the diaper 1 in the wet state has a longer step distance than the diaper 2 in the dry state, and therefore the diaper 1 in the wet state has a larger influence on the walking of the wearer than the diaper 2 in the dry state, and can be evaluated as being not easy to walk. Further, even in the wet state, since the diaper 3 has a longer step length than the diaper 1, the diaper 3 has a larger influence on the walking of the wearer than the diaper 1, and can be evaluated as being not easy to walk.

The influence of the diaper on the walking of the wearer is evaluated together with one or more measurement results of the change in the hip joint angle, the change in the pelvic angle, and the movement amount of the body center of gravity, and the measurement result of the step distance, whereby the evaluation of the diaper can be realized with higher accuracy.

A specific example of a method for evaluating the degree of gait influence using the step distance and the distance between the knees as information (gait parameters) indicating gait is described in test example 2 described below.

The gait influence evaluation system according to the present invention will be described based on a preferred embodiment.

The gait influence evaluation system 200 of the present embodiment acquires moving image data captured by a walking person via a network or by using a predetermined medium.

As shown in fig. 9 (a), the gait influence evaluation system 200 includes an acquisition unit 110, an extraction unit 120, a calculation unit 130, and a comparison evaluation unit 140. The acquisition unit 110 acquires moving image data acquired via a network or by using a predetermined medium into the information processing terminal 100. The extraction unit 120 extracts a specific part of a person in the acquired moving image data. As the extraction unit, a known bone information acquisition technique from a human body image, a motion capture technique by attaching a mark to a specific portion, or the like can be exemplified. The calculation unit 130 calculates gait parameters indicating gait using the extracted temporal change in the position of the specific portion. The comparison and evaluation unit 140 compares a gait parameter of a normal gait calculated from moving image data obtained by capturing a gait when the wearer is walking without wearing an absorbent article with a gait parameter of a wearing gait calculated from moving image data obtained by capturing a gait when the wearer is walking with an absorbent article, or compares a plurality of wearing gait parameters calculated from moving image data obtained by capturing a gait when the wearer is walking with a different absorbent article with each other, and outputs the comparison result. The comparison result is preferably output in a visually easy-to-grasp form, and for example, gait parameters to be compared are preferably summarized in one graph (refer to fig. 3 (c), fig. 4 (c)), or gait parameters to be compared are shown in one or more graphs in a row (refer to fig. 8 (b)). It is preferable to perform comparison display with other gait parameters, comparison display of past data, and the like. The gait influence evaluation system 200 includes an information processing terminal 100 capable of executing various processes, and the information processing terminal 100 includes an extraction unit 120, a calculation unit 130, and a comparison evaluation unit 140. The information processing terminal 100 includes an input device such as a keyboard and a pointing device, an arithmetic processing device, a storage unit, and the like.

The moving image data is moving image data captured by an imaging device, which may be a normal RGB camera, a black-and-white camera, or a spectral camera, and the performance and specification of the imaging device are not limited. The imaging device includes a video recorder, a camera built in a smart phone, a camera built in a tablet terminal, a WEB camera which can be attached to a personal computer or the like by a connection method such as a cable, and the like.

The photographer who uses the gait of the imaging device may be a parent, grandparent, or the like of the pedestrian, in addition to the developer of the absorbent article, and preferably imaging is performed by a camera incorporated in the smartphone.

The captured dynamic image data is preferably transmitted (delivered) to the development stage computing system 200 via a network or with a prescribed medium. The comparison result by the evaluation unit 140 may be output to a display unit, a printing device, or the like included in the development stage computing system 200, or may be transmitted to a smart phone.

A preferred example of the flow of the evaluation by the gait influence evaluation system 200 will be described with reference to fig. 9 (b).

Step S10 acquires a plurality of moving image data obtained by capturing gait of a person. The moving image data may be acquired directly from an imaging device included in the gait influence evaluation system 200, or may be acquired from an imaging device independent of the gait influence evaluation system 200 via a network or by using a predetermined medium.

Step S11 is a step of extracting a specific portion from the acquired moving image data. The specific part may be a part to which the marker is attached or a part of the body of the person who moves by walking calculated without attaching the marker. Specific parts include, but are not limited to, the top of the head, the eyebrows, the neck, the upper end of the sternum on the back side, the left and right acromion, the left and right elbow, the left and right wrist, the left and right anterior superior iliac spine, the left and right greater trochanter, the left and right knee, the left and right lateral femoral epicondyle (knee joint), the left and right lateral malleolus (foot joint), the left and right ankle, and the like.

Step S12 is a step of calculating gait parameters for a plurality of pedestrians from a plurality of moving image data. Step S13 is a step of outputting the comparison result directly to a display unit included in the gait influence degree evaluation system 200 or to another device such as a smart phone independent of the gait influence degree evaluation system 200 via a network or by using a predetermined medium.

In step S12, a gait parameter of a normal gait calculated from moving image data obtained by capturing a gait when the person is walking without wearing an absorbent article is compared with a gait parameter of a wearing gait calculated from moving image data obtained by capturing a gait when the person is walking with wearing an absorbent article, or a plurality of wearing gait parameters calculated from moving image data obtained by capturing a gait when the person is walking with wearing a different absorbent article are compared with each other. Specifically, the method can be the method described above or the method shown in the test example described later.

The gait influence evaluation program of the present invention is, for example, software that causes a computer to function as a gait influence evaluation system. As the computer, a known general-purpose computer, a smart phone, a tablet terminal, or the like can be used. The general-purpose computer includes CPU, ROM, RAM, SDD, HDD, and the like. The processing of steps S11 to S13 is realized by the CPU expanding the present program stored in the ROM, the optical disk, or the like in the RAM and executing the program. The above processing may be implemented by GPU (Graphics processing Unit ) or ASIC (Application Specific Integrated Circuit, application specific integrated circuit), FPGA (Field Programmable Gate Array ), or by a combination of ASIC and FPGA.

[ test example ]

The present invention will be described in more detail below with reference to test examples. However, the scope of the present invention is not limited to these test examples.

As pants-type diapers used in the test examples, the following 2 types of diapers 4 and 5 were manufactured.

[ diaper 4 ]

First, an absorber 4 having a cross-sectional structure shown in fig. 10 is disposed between a front sheet made of nonwoven fabric and a back sheet made of a resin film, and is formed as an absorbent body, and leakage-proof cuffs are provided on both side portions of the absorbent body, and leakage-proof cuff forming elastic members are fixed in an elongated state to the leakage-proof cuff forming sheets. The outer body is joined to the non-skin-facing surface side of the absorbent main body, and both side edges of the abdomen side portion and the back side portion of the outer body are joined to each other to form a pair of side seals. The absorbent body 4 of the diaper 4 thus obtained is composed of an absorbent core 40 containing a fibrous material and a water-absorbent polymer 46, and a core wrap 48 covering the surface of the absorbent core 40, and has a central absorbent body 4C and a pair of side absorbent bodies 4S, 4S in the crotch portion C, and a pair of curved guide portions 45, 45 between the central absorbent body 4C and the side absorbent bodies 4S. The absorbent core 40 has a central region 41 in the central absorbent body 4C and side regions 43 in the side absorbent bodies 4S, and the central region 41 and the side regions 43 are defined by a pair of curved guide portions 45, 45. The pair of curved guide portions 45, 45 extend in the longitudinal direction of the diaper in the crotch portion of the diaper. The curved guide portion 45 is formed by a slit penetrating the absorbent core 40 in the thickness direction Z. The absorbent body 4 of the diaper 4 is formed such that the core sheets 48 located on the skin-facing side and the non-skin-facing side of the absorbent core 40 are joined to each other in the gap.

In table 3 below, the respective structures of diapers 4 and 5 are shown. In fig. 10, W1 is the width of the central region 41, W2 is the width of the side regions, W3 is the width of the curved guide portion, and Wa is 1/2 of the width W1 of the central region.

[ diaper 5 ]

As the bending guide portion, instead of providing a slit in the absorbent core, a low basis weight portion having a thin thickness is provided in a part of the absorbent core, and except for this point, a diaper 5 having the same structure as the diaper 4 is produced.

TABLE 3

The diapers 1, 3, 4 and 5 described above were measured for 30mm compressive load.

160g of artificial urine is injected from the central position of the diaper to an injection point located 7cm away from the side of the abdomen in the longitudinal direction, and in a standard swelling state after standing for 5 minutes, the thickness of the crotch portion of the diaper bent so as to equally divide the width 2 of the diaper is reduced to a compression load of 30mm (hereinafter referred to as 30mm compression load) of 7N or less, more preferably 6.5N or less.

The 30mm compressive load was measured by the following method.

After the diaper was developed and stretched, the diaper was bent along the longitudinal center line CL so as to equally divide the width 2 of the diaper, and the diaper was used as the test body 1a. The test piece 1a was placed on a horizontal place without wrinkles or bending so that the longitudinal direction of the bent diaper (the direction perpendicular to the width direction Y, hereinafter also referred to as "longitudinal direction X") matches the horizontal direction. The test piece 1a was placed with a rectangular acrylic plate having a width of 5cm×a length of 15cm and a weight of 28.7g at a central position in the longitudinal direction X (hereinafter referred to as "first measurement position") and a position 2.5cm away from the central position toward the side of the abdomen a (hereinafter referred to as "second measurement position"). At this time, the acrylic plate is placed such that the width of the acrylic plate coincides with the longitudinal direction X of the diaper and the center of the width coincides with the first measurement position or the second measurement position. The acrylic plate was moved downward at a compression rate of 100 mm/min, and compressed to a thickness of 30mm in the test body 1a. The compression was performed using a material tester (for example, autograph AG-X, manufactured by Shimadzu corporation). The compressive load at the first measurement position and the second measurement position was measured at a diaper thickness of 30mm, and the average value at these 2 points was taken as 30mm compressive load.

The side absorber 4S in the normal swollen state was confirmed to have a compression load when the thickness thereof was compressed to 10mm (hereinafter referred to as "10mm compression load"), and contributed to the 30mm compression load. That is, by adjusting the compression load of 10mm of the side absorber 4S, the compression load of 30mm of the test body 1a can be adjusted within the above-described range.

From this viewpoint, the 10mm compression load of at least one side absorber 4S is preferably 4.5N or less, more preferably 4N or less, and is preferably 0.1N or more and 4.5N or less, more preferably 0.5N or more and 4N or less.

The 10mm compressive load of both the pair of side absorbers 4S, 4S is preferably within the above-described range.

The measurement method of the 10mm compression load of the side absorber 4S is as follows. First, the absorbent body 4 is taken out from the diaper in a normal swelling state, and is placed in a horizontal place without wrinkles or bending so that the skin-facing surface of the absorbent body 4 faces upward in the vertical direction. Next, a compression load when the side absorber 4S was compressed to a thickness of 10mm was measured by a material testing machine (for example, autograph AG-X manufactured by shimadzu corporation) equipped with a compression testing tool having a rod shape with a diameter of 2 cm. The measurement was performed at any 3 of the portions of the side absorber 4S where the absorbent core 40 was present, and the average value thereof was taken as a compression load of 10 mm.

Table 4 shows a 30mm compression load and a 10mm compression load of the side absorber.

TABLE 4

Compression physical properties	Diaper	1	Diaper 3	Diaper 4	Diaper 5
						Compression load of 30mm is rolled over to 2	7.52	10.21	5.77	6.88
Side absorber 10mm compression load	0.46	6.17	3.77	0.89

[ evaluation of gait influence degree I ]

The diapers 1 and 3 and the manufactured diaper 4 were evaluated for the degree of gait influence by the method having the following steps (a), (B) and (C). In the present evaluation method, 13 infants with a month age of 12 to 25 months were used as subjects.

First, in the step (a), a subject is walked for at least 3 walking cycles in a state where no diaper is worn (hereinafter referred to as "non-worn state"), and the walking state is monitored by a three-dimensional motion capture device (VICON imaging system×16 200 hz). In this monitoring, marks are attached to a plurality of parts of the body of the subject, position information and movement information of the marks in a walking state are acquired, and gait of the subject is monitored. In this monitoring, the subject was walked on a floor reaction force meter (force measuring plate AMTI, 2000 Hz) that measures the force received from the floor. The monitoring result obtained in the present step (a) is set as a result of the normal gait.

Next, in the step (B), the subject is walked for at least 3 walking cycles while wearing the diapers 1, 3 and 4, respectively, and the walking state is monitored by the three-dimensional motion capture device. In this monitoring, the subject is walked on the floor reaction force meter.

Diapers 1, 3 and 4 were prepared in a swollen state (hereinafter also referred to as "swollen state") in which 160g of physiological saline was injected by the following method. In the case of forming the swollen state, first, a mark (hereinafter referred to as "first mark") is marked with an oil pen at a center position located at the center in the longitudinal direction X (a crease in the crotch portion of the product) and at the center in the width direction Y in the unused diaper, and another mark is marked at a position 7cm apart from the center position marked with the first mark toward the side of the abdomen portion a in the longitudinal direction X, and the position marked with the other mark is taken as the injection point of physiological saline. Next, the portion forming the waist opening WH of the diaper was gripped, and 160g of physiological saline was injected at an injection rate of 5 g/sec to the injection point in a state where the crotch C of the diaper was drooped so that the center position of the first mark was the lowest position. The injection uses a tube pump. After the injection of physiological saline, the diaper was left to stand in the above-mentioned sagging state for 1 minute, and was used as a diaper in a swollen state.

The monitoring result obtained in the step (B) is used as a result of the gait at the time of wearing.

In the step (C), the result of the normal gait obtained in the step (a) and the result of the wearing gait obtained in the step (B) are compared. The comparison uses three-dimensional image analysis software (Visual 3D C-motion). Specifically, measurements of coronal hip angle of a normal gait and a gait when worn are compared.

The coronal hip joint angle is mainly an index indicating the movement amount of the thigh joint to the side of the pelvis, and when the pelvic coordinate system of XYZ axis of the pelvis and the femur coordinate system of XYZ axis of the thigh joint are assumed, the inclination angle of the X axis or the Z axis of the thigh joint coordinate system rotating around the Y axis of the pelvic coordinate system with respect to the Y-Z plane or the X-Y plane of the pelvic coordinate system is measured. In the present evaluation method, in order to compare the value of the coronal hip joint angle at the position of 80% of the walking distance in one walking cycle with the wearing gait, the value of the wearing gait is subtracted from the value of the normal gait. The "one walking cycle" is a period from when the left heel of the subject touches the floor surface to when the next left heel touches the floor surface during walking.

[ test example 1 ]

Regarding the diapers 1 and 3 and the manufactured diaper 4 (both in a swollen state), the value of the coronal hip joint angle at a position of 80% of the walking distance in one walking cycle and the total movement distance (cm) of the body center of gravity in the left-right direction were measured, and the normal gait (nude) and the gait at the time of wearing were compared. The results are shown in fig. 12 and 13.

In fig. 12, 13, + (2 asterisks) indicated a significant level of p <0.01/N, significant differences were confirmed between the 2 subjects compared, 1 asterisk) indicated a significant level of p <0.05/N, significant differences were confirmed, + (1 positive) indicated no significant differences were confirmed, but p <0.1/N. N is the number of detection times.

As shown in fig. 12, the manufactured diaper 4 had no significant difference from the bare diaper at the coronal hip angle as a gait parameter, but a tendency of difference was observed with the comparative diaper 3 having a significant difference from the bare diaper. On the other hand, there was no significant difference between diaper 1 and the bare body, but no difference from diaper 3 was observed.

As shown in fig. 13, the manufactured diaper 4 has no significant difference from the bare diaper 3 in the total movement distance in the left-right direction of the body center of gravity, which is a gait parameter, but tends to be different from the diaper 1.

As a result, according to the method for evaluating the degree of gait influence of the present invention, preferably using a three-dimensional image analysis, it is known that the manufactured diaper 4 has a smaller degree of influence on gait than other diapers, and the difference in the degree of influence on gait can be clearly distinguished among a plurality of diapers.

[ test example 2 ]

The following evaluation of gait influence II was performed by using the diapers 1 and 3 and the manufactured diaper 5.

[ evaluation of gait influence degree II ]

In the present evaluation method, 14 infants with a month age of 18 to 20 months were used as subjects. First, the test subject is walked in the non-wearing state and the wearing state of the diapers 1, 3, and 5, respectively, and the walking is imaged as a moving image. At this time, the subject is walked on the floor reaction force meter.

In the present evaluation method, the physiological saline solution was injected into the diaper to form a swollen state in the same manner as in the above-described evaluation I of the gait influence degree.

Next, bone information is acquired by openelse for moving image data of walking of the subject. The bone information is synthesized data obtained by extracting a portion such as a neck, a shoulder, an elbow, a wrist, a waist, a knee, or an ankle from dynamic image data, and by synchronizing the extracted portion with the dynamic image data and expressing the three-dimensional coordinates of the portion. Based on the bone information, the step distance (cm) and the interval (cm) between the knees of the subject at the time of walking are calculated, and the average value thereof is calculated. Based on the step distance of the bone information, the distance between the left and right sides of the midpoint of the line connecting the lateral malleolus and the medial malleolus is measured. The distance between the two knees based on the bone information is obtained by measuring the distance between the center of the right knee and the center of the left knee.

Based on bone information at the time of walking, the step distance is shown in fig. 14, and the interval between both knees (knee interval distance) is shown in fig. 15. Regarding the step distance and the interval between the knees, the statistical difference (significant difference) of 2 test cases was confirmed by the corresponding t-test.

Fig. 14 shows the interval between the knees at the time when the center of the knee is farthest from the perpendicular line from the center of gravity of the body. The larger the value of the interval between the knees, the more apart the left and right knees are during walking.

In fig. 14 and 15,/x (2 asterisks) indicated a significant difference between the 2 subjects compared at a significant level p <0.01, and (1 asterisk) indicated a significant level p < 0.05.

As shown in fig. 14 and 15, in both the step distance and the interval between both knees (knee interval distance) as gait parameters, the manufactured diapers 5 were not significantly different from the nude, but the diapers 1 and 3 were significantly different from the nude. In addition, there is also a significant difference between the diaper 5 and the diaper 3 in both the step distance and the interval between the knees (knee interval distance). According to the method for evaluating gait influence of the present invention, preferably, the method for calculating three-dimensional image coordinates from two-dimensional moving image data, it is possible to clearly distinguish the difference in the degree of influence on gait among a plurality of diapers.

The above embodiment further discloses the following evaluation method.

<1>

A method for evaluating the degree of influence of gait on an absorbent article, the method being characterized by:

comprising the following steps (A) - (C):

(A) A step of monitoring a person by taking a normal gait at least 3 walking cycles without wearing an absorbent article to be evaluated;

(B) A step of monitoring by taking a picture of gait at the time of wearing at least 3 walking cycles in a state where an absorbent article to be evaluated is worn; and

(C) A comparison step of comparing the normal gait with the gait when worn.

<2>

A method for evaluating the degree of gait influence of an absorbent article, which is characterized in that, for at least 2 different absorbent articles, the degree of influence of wearing of the absorbent article on gait is compared and evaluated, and the method for evaluating the degree of gait influence is characterized in that:

comprising the following steps (D) to (F):

(D) A step of monitoring a person by taking a picture of gait of the person when wearing the absorbent article while walking for at least 3 walking cycles;

(E) A step of monitoring a gait of wearing the absorbent article by taking a picture of the gait of the wearer while walking for at least 3 walking cycles; and

(F) A comparison step of comparing the wearing gait of the one absorbent article with the wearing gait of the other absorbent article.

<3>

The method for evaluating gait influence according to <1> or <2>, wherein,

in the monitoring step, dynamic image data is acquired,

the comparing step includes a three-dimensional analyzing step of analyzing using three-dimensional information obtained from the dynamic image data acquired in the monitoring step.

<4>

The method for evaluating gait influence according to <3> above, wherein,

in the monitoring step, two-dimensional dynamic image data is acquired by an RGB camera, a black-and-white camera or a spectral camera,

the method includes a three-dimensional information acquisition step of calculating three-dimensional image coordinates from the two-dimensional moving image data acquired in the monitoring step, thereby obtaining the three-dimensional information used in the three-dimensional analysis step.

<5>

The method for evaluating gait influence according to any one of the above items <1> to <4>, wherein,

in the comparison step, the coronal hip joint angles are compared.

<6>

The method for evaluating gait influence according to any one of the above items <1> to <4>, wherein,

in the comparison step, the pelvic angle is compared.

<7>

The method for evaluating gait influence according to any one of the above items <1> to <4>, wherein,

in the comparing step, the sagittal hip joint angle is compared.

<8>

The method for evaluating gait influence according to any one of the above items <1> to <4>, wherein,

in the comparing step, the movement amount of the body's center of gravity is compared.

<9>

The method for evaluating gait influence according to any one of the above items <1> to <4>, wherein,

in the comparing step, the step sizes are compared.

<10>

The method for evaluating gait influence according to any one of the above items <1> to <4>, wherein,

in the comparing step, the distance between the two knees is compared.

<11>

The method for evaluating gait influence according to any one of the above items <1> to <4>, wherein,

in the comparing step, a coronal hip joint angle obtained from a relationship with a coordinate system set in the pelvis or a sagittal hip joint angle obtained from a relationship with a coordinate system set in the pelvis is compared.

<12>

The method for evaluating gait influence according to <5> above, wherein,

In the comparing step, an integral value of a whole or a part of a region of one walking cycle in the chart of coronal hip joint angle change of one walking cycle is calculated, and the integral value is compared between a normal gait and a wearing gait or between gaits at the wearing time of different absorbent articles.

<13>

The method for evaluating gait influence according to <5> above, wherein,

in the comparison step, the maximum or minimum value of the coronal hip joint angle for one walking cycle is compared with the normal gait and the gait at the time of wearing or the gaits at the time of wearing different absorbent articles.

<14>

The method for evaluating gait influence according to <5> above, wherein,

in the comparison step, the value of the coronal hip angle at the end of one walking cycle is compared with the normal gait and the wearing gait or with each other at the wearing time of different absorbent articles.

<15>

The method for evaluating gait influence according to <5> above, wherein,

in the comparison step, the value of the coronal hip joint angle at a predetermined point in the step period of one walking cycle is compared between a normal gait and a wearing gait or between different wearing gaits of the absorbent article.

<16>

The method for evaluating gait influence according to <6> above, wherein,

in the comparison step, an integral value of a whole or a part of a region of one walking cycle in the map of pelvic angle change of one walking cycle is calculated, and the integral value is compared between a normal gait and a wearing gait or between gaits at the wearing time of different absorbent articles.

<17>

The method for evaluating gait influence according to <6> above, wherein,

in the comparison step, the maximum value of the pelvic angle for one walking cycle is compared between the normal gait and the gait at the time of wearing or between the gaits at the time of wearing different absorbent articles.

<18>

The method for evaluating gait influence according to <6> above, wherein,

in the comparison step, the differential values in the predetermined region of the map of the pelvic angle change in one walking cycle are compared between the normal gait and the gait at the time of wearing or between the gaits at the time of wearing different absorbent articles.

<19>

The method for evaluating gait influence according to <7> above, wherein,

in the comparison step, an integral value of a whole or a part of a region of one walking cycle in a chart of sagittal hip joint angle change of one walking cycle is calculated, and the integral value is compared between a normal gait and a wearing gait or between gaits when different absorbent articles are worn.

<20>

The method for evaluating gait influence according to <7> above, wherein,

in the comparing step, the difference between the maximum value and the minimum value of the sagittal hip joint angle in one walking cycle is compared between the normal gait and the gait at the time of wearing or the gaits at the time of wearing of different absorbent articles.

<21>

The method for evaluating gait influence according to <8> above, wherein,

in the comparison step, the total movement distance in the lateral direction of the body center of gravity in one walking cycle is compared with the normal gait and the wearing gait or with the gaits of different absorbent articles when worn.

<22>

The method for evaluating gait influence according to <8> above, wherein,

in the comparison step, the maximum value or the minimum value of the movement distance in the vertical direction of the body center of gravity in one walking cycle or 1/2 walking cycle is compared with the normal gait or the gaits at the time of wearing different absorbent articles.

<23>

The method for evaluating gait influence according to <8> above, wherein,

in the comparison step, the difference between the maximum value and the minimum value in the vertical direction of the body center of gravity, that is, the total movement distance in one walking cycle or 1/2 walking cycle is compared between the normal gait and the gait at the time of wearing or between the gaits at the time of wearing different absorbent articles.

<24>

The method for evaluating gait influence according to any one of the above items <1> to <23>, wherein,

before the step (B), or the step (D) and the step (D), performing an acclimatization step of adapting the absorbent article to the body shape of the walking person.

<25>

The method for evaluating gait influence according to any one of the above items <1> to <24>, wherein,

the absorbent article is a disposable diaper for infants.

<26>

The method for evaluating gait influence according to any one of the above items <1> to <25>, wherein,

the absorbent article is a pants-type disposable diaper.

<27>

A gait-impact evaluation system that evaluates an impact of wearing an absorbent article on a gait, the gait-impact evaluation system comprising:

an acquisition unit for acquiring moving image data obtained by capturing a walking person;

an extraction unit for extracting a specific part of a person in the acquired moving image data;

a calculation unit for calculating gait parameters representing gait using the extracted time-varying position of the specific portion; and

and a comparison and evaluation unit that compares a gait parameter of a normal gait calculated from moving image data obtained by capturing a gait when the absorbent article is not worn with a gait parameter of a wearing gait calculated from moving image data obtained by capturing a gait when the absorbent article is worn, or compares a plurality of wearing gait parameters calculated from moving image data obtained by capturing a gait when the absorbent article is worn with different ones, and outputs a comparison result.

<28>

A gait impact evaluation program, characterized in that:

the computer was caused to function as the gait impact evaluation system described in <27 >.

Industrial applicability

According to the method for evaluating the gait influence of the absorbent article of the present invention, the influence of the absorbent article such as a disposable diaper on the gait of the wearer can be evaluated with high accuracy.

Claims (27)

1. A method for evaluating the degree of influence of gait on an absorbent article, the method being characterized by:

comprising the following steps (A) - (C):

(A) A step of monitoring a person by taking a normal gait at least 3 walking cycles without wearing an absorbent article to be evaluated;

(B) A step of monitoring by taking a picture of gait at the time of wearing at least 3 walking cycles in a state where an absorbent article to be evaluated is worn; and

(C) A comparison step of comparing the normal gait with the gait when worn.

2. A method for evaluating the degree of gait influence of an absorbent article, which is characterized in that, for at least 2 different absorbent articles, the degree of influence of wearing of the absorbent article on gait is compared and evaluated, and the method for evaluating the degree of gait influence is characterized in that:

Comprising the following steps (D) to (F):

(D) A step of monitoring a person by taking a picture of gait of the person when wearing the absorbent article while walking for at least 3 walking cycles;

(E) A step of monitoring a gait of wearing the absorbent article by taking a picture of the gait of the wearer while walking for at least 3 walking cycles; and

(F) A comparison step of comparing the wearing gait of the one absorbent article with the wearing gait of the other absorbent article.

3. The method for evaluating gait influence according to claim 1 or 2, wherein:

in the monitoring step, dynamic image data is acquired,

the comparing step includes a three-dimensional analyzing step of analyzing using three-dimensional information obtained from the dynamic image data acquired in the monitoring step.

4. The method for evaluating gait influence according to claim 3, wherein:

in the monitoring step, two-dimensional dynamic image data is acquired by an RGB camera, a black-and-white camera or a spectral camera,

the method includes a three-dimensional information acquisition step of calculating three-dimensional image coordinates from the two-dimensional moving image data acquired in the monitoring step, thereby obtaining the three-dimensional information used in the three-dimensional analysis step.

5. The method for evaluating gait influence according to any one of claims 1 to 4, wherein:

in the comparison step, the coronal hip joint angles are compared.

6. The method for evaluating gait influence according to any one of claims 1 to 4, wherein:

in the comparison step, the pelvic angle is compared.

7. The method for evaluating gait influence according to any one of claims 1 to 4, wherein:

in the comparing step, the sagittal hip joint angle is compared.

8. The method for evaluating gait influence according to any one of claims 1 to 4, wherein:

in the comparing step, the movement amount of the body's center of gravity is compared.

9. The method for evaluating gait influence according to any one of claims 1 to 4, wherein:

in the comparing step, the step sizes are compared.

10. The method for evaluating gait influence according to any one of claims 1 to 4, wherein:

in the comparing step, the distance between the two knees is compared.

11. The method for evaluating gait influence according to any one of claims 1 to 4, wherein:

In the comparing step, a coronal hip joint angle obtained from a relationship with a coordinate system set in the pelvis or a sagittal hip joint angle obtained from a relationship with a coordinate system set in the pelvis is compared.

12. The method for evaluating gait influence according to claim 5, wherein:

in the comparing step, an integral value of a whole or a part of a region of one walking cycle in the chart of coronal hip joint angle change of one walking cycle is calculated, and the integral value is compared between a normal gait and a wearing gait or between gaits at the wearing time of different absorbent articles.

13. The method for evaluating gait influence according to claim 5, wherein:

in the comparison step, the maximum or minimum value of the coronal hip joint angle for one walking cycle is compared with the normal gait and the gait at the time of wearing or the gaits at the time of wearing different absorbent articles.

14. The method for evaluating gait influence according to claim 5, wherein:

in the comparison step, the value of the coronal hip angle at the end of one walking cycle is compared with the normal gait and the wearing gait or with each other at the wearing time of different absorbent articles.

15. The method for evaluating gait influence according to claim 5, wherein:

in the comparison step, the value of the coronal hip joint angle at a predetermined point in the step period of one walking cycle is compared between a normal gait and a wearing gait or between different wearing gaits of the absorbent article.

16. The method for evaluating gait influence according to claim 6, wherein:

in the comparison step, an integral value of a whole or a part of a region of one walking cycle in the map of pelvic angle change of one walking cycle is calculated, and the integral value is compared between a normal gait and a wearing gait or between gaits at the wearing time of different absorbent articles.

17. The method for evaluating gait influence according to claim 6, wherein:

in the comparison step, the maximum value of the pelvic angle for one walking cycle is compared between the normal gait and the gait at the time of wearing or between the gaits at the time of wearing different absorbent articles.

18. The method for evaluating gait influence according to claim 6, wherein:

In the comparison step, the differential values in the predetermined region of the map of the pelvic angle change in one walking cycle are compared between the normal gait and the gait at the time of wearing or between the gaits at the time of wearing different absorbent articles.

19. The method for evaluating gait influence according to claim 7, wherein:

in the comparison step, an integral value of a whole or a part of a region of one walking cycle in a chart of sagittal hip joint angle change of one walking cycle is calculated, and the integral value is compared between a normal gait and a wearing gait or between gaits when different absorbent articles are worn.

20. The method for evaluating gait influence according to claim 7, wherein:

in the comparing step, the difference between the maximum value and the minimum value of the sagittal hip joint angle in one walking cycle is compared between the normal gait and the gait at the time of wearing or the gaits at the time of wearing of different absorbent articles.

21. The method for evaluating gait influence according to claim 8, wherein:

In the comparison step, the total movement distance in the lateral direction of the body center of gravity in one walking cycle is compared with the normal gait and the wearing gait or with the gaits of different absorbent articles when worn.

22. The method for evaluating gait influence according to claim 8, wherein:

in the comparison step, the maximum value or the minimum value of the movement distance in the vertical direction of the body center of gravity in one walking cycle or 1/2 walking cycle is compared with the normal gait or the gaits at the time of wearing different absorbent articles.

23. The method for evaluating gait influence according to claim 8, wherein:

in the comparison step, the difference between the maximum value and the minimum value in the vertical direction of the body center of gravity, that is, the total movement distance in one walking cycle or 1/2 walking cycle is compared between the normal gait and the gait at the time of wearing or between the gaits at the time of wearing different absorbent articles.

24. The method for evaluating gait influence according to any one of claims 1 to 23, wherein:

The absorbent article is a disposable diaper for infants.

25. The method for evaluating gait influence according to any one of claims 1 to 24, wherein:

the absorbent article is a pants-type disposable diaper.

26. A gait-impact evaluation system that evaluates an impact of wearing an absorbent article on a gait, the gait-impact evaluation system comprising:

an acquisition unit for acquiring moving image data obtained by capturing a walking person;

an extraction unit for extracting a specific part of a person in the acquired moving image data;

a calculation unit for calculating gait parameters representing gait using the extracted time-varying position of the specific portion; and

and a comparison and evaluation unit that compares a gait parameter of a normal gait calculated from moving image data obtained by capturing a gait when the absorbent article is not worn with a gait parameter of a wearing gait calculated from moving image data obtained by capturing a gait when the absorbent article is worn, or compares a plurality of wearing gait parameters calculated from moving image data obtained by capturing a gait when the absorbent article is worn with different ones, and outputs a comparison result.

27. A gait impact evaluation program, characterized in that:

the gait influence evaluation system of claim 26, wherein the computer is caused to function.

Images