Oct. 17, 2023

Ability enhancement by recovering human inherent abilitiesIntroduction to the New Ability Enhancement Concept ERIA^TM

Toyota's Frontier Research Center conducts human research that contributes to health in order to achieve our mission of "Producing Happiness for All." In this article, lead researcher Tadashi Odashima introduces Enhancement by Recovering Inherent Abilities (ERIA), a new human ability enhancement concept, and the progress of the research in "How can we help people's bodies and minds become healthier while sitting?" featured at the end of the October 2021 article, "Research for Turning Sedentary Time into Health-Promoting Time?!"

The old Japanese were Amazing

: Fig. 1 Old Japanese woman carrying charcoal^*1

―What is this impactful picture?

Odashima: This is a picture taken in 1911 that shows the amazingness of the old Japanese people at that time. According to Reference^*1, the location where the photo was taken was in the mountains of Nikko, and the bale was filled with charcoal, which she carried on foot along a 6.5 km mountain road. Depending on how the charcoal was packed, it must have been quite hard work to carry the bales, which were not light considering their size, on the mountain paths with poor footholds. Some may think that this person was exceptionally strong, but there are other stories of people's athletic abilities that amaze us in the past.

―What kind of stories?

Odashima: There is a record^*2 of a rickshaw man who pulled a rickshaw from Tokyo to Nikko, a distance of 110 km, carrying 54 kg of passengers, in 14.5 hours during the Meiji Era (1868-1912). The same document states that it took 14 hours to change horses six times when traveling the same distance by carriage, which shows the amazing power of the rickshaw man. As we learned about these stories, we began to think that it was not just the old Japanese people were amazing, but that modern Japanese people are losing their abilities, and we began to think about improving their abilities by regaining those lost abilities. We refer to this concept as ERIA.

New Ability Enhancement Concept: ERIA

―Can you tell me more about ERIA?

Odashima: While ability enhancement is commonly associated with training such as various types of muscle training and brain training, and the use of tools such as glasses and hearing aids, ERIA's approach is fundamentally different. Figs. 2 and 3 show schematically the relationship between the brain, muscle, and sensory organs. The traditional way to expand capabilities is to strengthen the vertices of the triangle as shown in Fig. 2, however, the ERIA concept focuses on the "connections" between the vertices as shown in Fig. 3, especially the relationships that are initially present but no longer used in daily life. We thought that the amazingness of people in the past, which I introduced at the beginning of this article, was that the connection between the apexes of this triangle worked better in people in the past than in people today, and they were able to demonstrate high athletic ability because they were able to efficiently coordinate the various parts of their bodies. We named ERIA after the first letter of each word for Enhancement by Recovering Inherent Abilities.

Fig. 2 Conventional enhancements
Fig. 3 Enhancements in ERIA

Utilization of ERIA―Turning Sedentary Time into Health-Promoting Time

―I understand that you and your colleagues are exploring ways to utilize the idea of ERIA to improve health just by sitting. Why did you start such an initiative?

Odashima: Details are given in the aforementioned article, "Research for Turning Sedentary Time into Health-Promoting Time?!"^*3 There is a study that showed that prolonged sedentary time is associated with lower physical activity, increased risk of disease, and increased risk of death. However, we cannot stop sitting at all. For example, for long-distance drivers, long periods of sitting are inevitable. Then, what if sedentary time could be conversely turned into health-enhancing time? If this were to happen, it would be a dream come true to improve one's health just by sitting around.

―But is there such a convenient way to achieve this?

Odashima: The clue was in the postural maintenance ability inherent in all people. Humans try to maintain their body position, posture, and equilibrium without being aware of it through reflex movements called postural reflexes. If the pelvis is tilted, for example by tilting the seat of the chair in which you are sitting, humans will unconsciously try to maintain a stable posture. Postural changes in the trunk are caused by the antigravity muscles, the deep muscles (inner muscles) around the spine, which are also known to be difficult to activate consciously. We thought that even if we could not activate the deep muscle intentionally, the tilting of the seat surface would induce movement that would activate the deep muscles more than usual, and that by tilting it very slowly and very slightly, we could promote this activation almost without being aware of it. We have devised and are researching a slight tilt swivel chair as a way to test this hypothesis.

: Fig. 4 Pelvic tilt produces trunk motion

―What else can you say about the slight tilt swivel chair?

Odashima: The motion of the slight tilt swivel chair is shown in Movie 1. The seat is supported by an elastic support and three support posts. However, one of the support columns is slightly shorter than the other two, so that the seat tilts very slightly when a human sits on it. In addition, three support posts are fixed at equal intervals on the circumference of the rotating disk and rotate with it. This mechanism changes the direction of the seat's tilt from time to time.

: Movie 1 Structure of the slight tilt swivel chair

―I totally understood. By the way, does such a simple structure really induce deep muscle activity?

: Fig. 5 Muscle-solid THUMS

Odashima: Yes, we believe that deep muscle activity is triggered. However, to really know the activity of the deep muscles, a needle electrode must be inserted into the body. We therefore decided to use a musculoskeletal simulator to calculate which deep muscles would be affected by sitting on the slight tilt swivel chair. We don't want to stick needle electrodes all over our body (laughs). The musculoskeletal simulator used a model that extends the Total HUman Model for Safety (THUMS^Ⓡ)^*4 with muscles as three-dimensional elements developed at Toyota Central R&D Labs., Inc.. There are 312 implemented muscles, allowing visualization of the behavior of muscles throughout the body, including deep muscles^*5. THUMS was seated on the slight tilt swivel chair as shown in Fig. 5, and the generation of muscular force throughout the body was calculated to maintain the head position.

Movie 2 compares THUMS sitting on a chair with a fixed seat surface to sitting on a slight tilt swivel chair. The activity level of all muscles in the body is indicated by color changes. The red areas show higher activity, but the high activity areas change in the slight tilt swivel chair. By graphing these changes, interesting results were revealed.

: Movie 2 Comparison of whole-body muscle activity changes

: Fig. 6 Differences in changes in the activation of deep lumbar back muscles due to chairs

―Please explain the graph.

Odashima

Fig. 6 compares the changes in the activation of the deep lumbar back muscles in different chairs. The vertical axis is proportional to muscle strength, with a large value indicating tension and a low value indicating weakness (relaxation). For the fixed seat chair in (a), the values converge to almost constant values within 10 seconds after seating. On the other hand, the slight tilt swivel chair in (b) shows a change in value over time. Time (1) is the time when the pelvic tilt has shifted from left to right, and here the magnitude of muscle activation of the left and right iliopsoas muscles swapped. It is thought that the tilt of the seat caused a reversal of the tightness and relaxation of the right and left iliopsoas muscles. These tilt-related changes in muscle activity were also observed in the deep muscles of the abdominal and neck^*6. These results indicate the following:

Tension and relaxation of deep muscles are repeated
A very slight change in the tilt of the seat surface affects the deep muscles from the lumbar region to the cervical region
However, the level of activity generated is not high enough to expect an increase in muscle mass

The repetition of tension and relaxation occurs here and there throughout the body, allowing for constant changes in the seated person's posture. This is expected to reduce the stress on the body caused by prolonged sitting.

―I see that the tilt of the seat causes changes in the deep muscles. What can you say about this in view of the ERIA idea?

Odashima: The stimulation of the slight tilt of the seat surface by the slight tilt swivel chair repeatedly causes the coordination of muscles in various parts of the body to tense and relax. We believe that by strengthening muscle coordination through this repetition, we can expect to improve the ability to control posture with precision, which has been inactive. This is exactly the kind of ability enhancement that is consistent with the idea of ERIA.

Future perspectives

―Finally, could you tell me about future perspectives?

Odashima: First of all, by sitting on the actual prototype of the slight tilt swivel chair, we would like to confirm the answers to the following questions:
Is postural control ability improved?
What other effects will it have on posture control?

: Fig. 7 Prototype of slight tilt swivel chair

We are also interested in why people lose abilities that they should naturally have. We imagine that this is probably the result of lifestyle changes due to cultural and social changes, and we believe that tracing it backward may reveal a way to regain competence. And we are eager to explore further applications by developing the ERIA concept.

References

*1	National Geographic Magazine November 1911, GLIMPSES OF JAPAN, p.986.
*2	Erwin von Bälz, "Nutritional balance and efficacy of plant foods in the working class", Chugai Medical Journal, No. 516 (1901), pp.1247-1249
*3	Research for Turning Sedentary Time into Health-Promoting Time?!
*4	THUMS
*5	Yuko Nakahira, Masami Iwamoto, "Estimation of physical burden while holding a box in a half-crouching position using a whole-body finite element model with 3D skeletal muscles," Transactions of the JSME, Vol.89, No.922 (2023), pp.1-15.
*6	Tadashi Odashima, Yuko Nakahira, "Assessment of motion produced by time-varying micro-seated plane inclination," and Robotics Mechatronics 2023 Lecture Progress 2A2-H08

Author

Tadashi Odashima
Project Manager, Human Research Group, R-Frontier Division
Engaging in human research. He likes making things as well as robotics and qigong.