A questionnaire survey was conducted to investigate the condition with the highest frequency of falls as an external factor of falls. The subjects of the questionnaire are students of Fukuoka Institute of Technology and residents around the university. Data were collected and analyzed about the age, sex, existence of falling experience in the past year, existence of the injury, fall place, fall time and fall cause. The content of the questionnaire includes age, gender, experience of falls within the past year, presence of injury, location of fall, time zone of fall, cause of fall, etc.

Since many people have experienced falls, including stumbling, it was found that stumbling occurred at any age [6], and a questionnaire survey was conducted to obtain detailed data specific to stumbling. The questionnaire used a paper-based survey and a Google form survey together.

Experiments have shown that the physical functions of young people wearing elderly Simulated Experience Kit are similar to those of the elderly [7].

We used SANWA Elderly person simulated experience teaching material expert set III to simulate the state of the elderly (Figure 1). Supporters are attached to the knees and elbows to limit the range of motion, the weight band at the wrists and ankles makes the body heavy, and the vest with a weight forcefully puts the user in a leaning posture. It is a tool used to experience the posture and movement of a person.

Figure 2 shows the maximum bending angle when the kit is installed.

The knee and elbow supporters limit the range of motion, making it difficult to bend the knee and elbow at right angles (Figure 3).

As internal factors of a fall, for what kind of posture when the stumbled to

analyze whether the lead to the fall, to shoot the moment of falling or stumbling with a high-speed camera. The degree of joint bending and the appropriate toe height are calculated based on the captured images. Similarly, we give examples of how to walk easily and features, compare them, and propose a better way of walking.

The model of the high-speed camera is JVC HD MEMORY CAMERA GC-LJ25 (Figure 4) [8]. The shutter speed is auto, the recording setting is 300 fps, and 640 × 360 pixels. Connect the camera to the iPad by direct connection and operate it using the special application “Sports Coaching CAM” [9].

As internal factors fall, what walking in order to analyze whether the likely fall to investigate the movement of the center of gravity during walking using the pressure distribution sensor mat.

The equipment used in the experiment is pressure distribution measuring device FSA/BodiTrak bed system (Figure 5). The sensors are arranged vertically and horizontally 1 inch square, are thin and have excellent flexibility, and even small objects can detect contact within the range that can be read by one sensor (Table 1).

Pressure distribution sensor mat control software is FSA Software Ver 4.1.001. The electric signal of the pressure distribution sensor mat is displayed on the map as pressure data. At the same time, the line connecting the pressure center points in time series (pressure center line) and the pressure data in 3D map are displayed. It is also possible to change the measurement speed and edit the cut and paste.

A pressure distribution sensor mat (BodiTrak) is laid on a flat floor, a distance of 30 cm is taken from the edge of the mat, and walking is started from that point (Figure 6). The subjects were four men and four women, all around the age of twenty. When walking, ask them to take off their shoes and put them on socks. In addition, in the case of the elderly simulation experience kit is not mounted, and the case that reproduces the walking for the elderly at the time of mounting is measured and compared. Do not give detailed instructions to the subject and simply say, “Please walk normally”.

Among men and women in their 20 s, 20% have experienced a fall, and among elderly people aged 60 to 80, as many as 46% have experienced a fall. In addition, among the elderly who have experienced falls, the proportion of injuries such as broken teeth or facial injuries has reached 66%. Therefore, it can be seen that the elderly are more likely to fall and get injured.

The material of the stumbled area is asphalt, tiles, flooring in order (Figure 7).

The most worn ones were sneakers, sandals and slippers were also mentioned (Figure 8).

The causes of stumbling without being caught by things were the most inattentiveness such as being dim, looking away, and looking at the smartphone, followed by physical problems such as the leg not rising (Figure 9).

Instantly fall or stumble on a high-speed camera to analyze, when tripped flat ground without obstacles occur, cause of stumbling roughly divided into two types. The first is rubbing the toes against the ground, and the second is rubbing the soles of the feet against the ground.

When the toes rub the ground, it was found that a stumbling occurred when the heel of the stepped foot was raised too much (Figure 10).

When the sole of the foot rubs the ground, it was found that the sole of the foot was parallel to the ground for a long time, the knee was not raised, and just before stumbling, the patient leaned forward more than usual (Figure 11).

The narrower the movement range of the center of gravity coordinate and the smaller the support base [11], the easier it is to lose balance. The base surface of the support is an area where a line connects the parts where the body and the support are in contact with the floor surface (Figure 12). The stability limit is the limit region where the center of gravity of the body can be separated from the center of the supporting base without losing the balance.

Therefore, we focus on the movement of the barycentric coordinates and consider the balance during walking. Figures 13-15 show the barycentric coordinates detected by the pressure distribution sensor mat in chronological order from bottom to top (hereinafter referred to as the pressure center line), each of which is a 20-year-old subject’s kit. It is classified by the presence/absence of wearing and the gender without wearing the elderly simulated experience kit.

Generally, the greater the variation of the pressure center line, the wider the stability limit and the more difficult it is to fall. Wearing the simulated elderly experience kit increased the number of steps and widened the support base (Figure 13).

In addition, in comparison with gender, the pressure center line is slightly linear for women overall (Figure 14).

However, the pressure center line of some men is similar to that of women in the number of steps, stride length, and movement of the center of gravity (Figure 15).