Research for Turning Sedentary Time into Health-Promoting Time?!Research for Turning Sedentary Time into Health-Promoting Time?!

October 12, 2021

Research for Turning Sedentary Time into Health-Promoting Time?!

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  • SDG ICON. Goal 3: Good health and well-being

At some point later in this century, people may be able to lead more convenient and prosperous lives thanks to technological innovations, such as fully automated driving, a home robot for each family, and mobile office spaces. But what if these advances make people more prone to sickness and shorter life spans? Research shows that if humans are sedentary for long periods, their physical activity level declines, increasing the risk of disease and death.1-5 The current sitting time (median value) among Japanese is 7 hours,6 which can be expected to increase in the future when people move their bodies even less.7 Thus, we wondered whether it could be possible to improve health even with long sedentary periods, and we began investigating that question in 2020. This article describes that research.

Applying Experience from Developing a Rehabilitation Assist Robot

Regular exercise, adequate rest and nutritionally balanced diet are usually regarded as the three principles for improving health. Among them, we decided to focus on exercise by applying the know-how we cultivated when developing the rehabilitation assist robot, Welwalk WW-2000(Figure 1). That robot was designed to provide rehabilitation support to individuals with lower limb paralysis as a result of stroke or other causes. If common exercise methods are plotted along axes for effectiveness and continuity (Figure 2), most of them turn out to be effective but difficult to continue; alternatively, they are easy to continue but not effective: very few exercise methods satisfy both requirements. Therefore, our aim was to simultaneously achieve effectiveness and continuity with the goal of attaining sitting time = exercise time.

  • Welwalk WW-2000Welwalk WW-2000
    Figure 1. Welwalk WW-2000
  • Existing exercise methods (axis of compliance and effect)Existing exercise methods (axis of compliance and effect)
    Figure 2. Existing exercise methods
    (continuity and effectiveness axes)

Focus on Low Exercise Level at Elderly Care Facilities

One facility of the Toyota Motor Health Insurance Society is an elderly health-care facility called Joystay. To avert COVID-19 infection there, restrictions have been placed on the residents’ movements among the floors. Accordingly, rehabilitation opportunities have become restricted, and ensuring that the residents get sufficient exercise is a major challenge. Generally, when the amount of exercise decreases and sedentary time rises, muscles atrophy and bones become brittle. Further, the range of joint movements becomes narrower, increasing the risk of falls when walking, standing up, or sitting down. Our hope was to provide the elderly residents with opportunities to securely increase the amount of exercise for their lower limbs without having to receive assistance from other people. After consulting the doctors and physical therapists at the Toyota Memorial Hospital as well as the staff of Joystay, we proposed the seated pedal exerciser detailed in Table 1.

  • Requirements for development equipmentRequirements for development equipment
    Table 1. Requirements for prototype exerciser

To validate the effectiveness of the pedal exerciser, we worked jointly with Toyota Central R&D Labs., Inc., utilizing a human musculoskeletal finite element analysis model. The results confirmed that the range of movements of the joints used changed when the steps of the exerciser were moved back and forth or tilted. In addition, the load on individual joints was much smaller than during the action of standing up or starting to walk—even when the equipment load was set to its maximum level during usage (40 W) (Figure 3).

  • Joint research with Toyota Central R & D Labs., Inc. Simulation results using a finite element analysis modelJoint research with Toyota Central R & D Labs., Inc. Simulation results using a finite element analysis model
    Figure 3. Joint research with Toyota Central R&D Labs., Inc.: results of simulations using a human musculoskeletal finite element analysis model
  • Features of the developed foot pedaling exercise equipmentFeatures of the developed foot pedaling exercise equipment
    Figure 4. Characteristics of the developed pedaling

Figure 4 shows the completed prototype exerciser. It can be employed when the user is seated; it has an elliptical orbit, which is less stressful for the user’s knees, and a low load (5–40 W), which is gentle even for frail elderly people. Small enough to be portable, it can also be adjusted to match the user’s range of joint movements. Further, to provide a sense of accomplishment based on the distance pedaled with people who are exercising together, a game was introduced: it awards users with collecting scarlet ink stamps by visiting virtual shrines and temples to help maintain motivation in continuing their rehabilitation efforts.
With cooperation from Joystay, the prototype exerciser was used by residents for 10–15 minutes a day, five times a week for about two months (Figure 5). The results confirmed some effectiveness in maintaining or improving the movements that occur in daily life, including the following: expanding the range of joint movements (Figure 6); improvements in walking ability (Figure 7); balance (Figure 8); and the ability to stand up (Figure 9).

  • Rehabilitation of pedaling exercise (cooperation with Joysty)Rehabilitation of pedaling exercise (cooperation with Joysty)
    Figure 5. Pedaling movements in rehabilitation (courtesy of Joystay)
  • Evaluation result of ankle joint (right foot) -plantar flexion range of motion [deg]Evaluation result of ankle joint (right foot) -plantar flexion range of motion [deg]
    Figure 6. Foot joint (right foot): plantar flexion joint movement range (degrees)
  • 10m walking time [s] Evaluation result10m walking time [s] Evaluation result
    Figure 7. Time (seconds) required for walking 10 meters
  • Evaluation of standing time with one leg open [sec]Evaluation of standing time with one leg open [sec]
    Figure 8. Ability to balance on one leg with the eyes open (seconds)
  • Evaluation of 30-second rise test [times]Evaluation of 30-second rise test [times]
    Figure 9. Thirty-second stand-up test (number of times)

Converting Office Sedentary Time to Health-Promoting Time

During that joint research with Toyota Central R&D Labs., we observed that users of the pedal exerciser were also employing their trunk muscles. They did that so as not to lose balance during pedaling motions when their trunk swayed sideways without a backrest.
As a consequence of that finding, we investigated body structures in greater detail. We discovered that human bodies have a mechanism called a kinetic chain: movements in the feet lead to movements in the foot joints, knee joints, hip joints, and then up to the trunk.
We discovered that if a kinetic chain is produced from the lower limbs to the trunk, it is also possible to achieve exercising of the trunk muscles (represented by the vertical and transverse muscles of the abdomen and erector spinae muscles) when the user exercises the lower limbs while seated.
We also found that the pelvis does not move much if the seat of the exerciser is fixed, preventing a kinetic chain from occurring during such exercise. Therefore, to achieve a kinetic chain between the lower limbs and trunk, we designed the seat to be unstable.
Further, we observed that making the pedaling movements follow a horizontally long elliptical orbit and providing a transversal turning freedom (yawing axis) to the seat resulted in rotational movements of the lower limbs and trunk similar to those that occur when walking. Those movements can be seen in the video.

  • Swinging chair that also moves the trunk in the movement chain of foot rowing exercise and its movement (left:real movement, right:simulation movement)Swinging chair that also moves the trunk in the movement chain of foot rowing exercise and its movement (left:real movement, right:simulation movement)
    movie. Rocking chair that also exercises the trunk based on a kinetic chain of pedaling movements; the chair’s movements (right, motion capture)

Using Kinetic Chain for Effective Exercise in a Short Time When Seated

On the basis of those findings, we made a new prototype exerciser for offices. It has a horizontally long elliptical orbit for pedaling, an unstable seat, and a transversal turning freedom (yawing axis) so that a kinetic chain can occur more effectively. We asked two office workers who were not in the habit of exercising to pedal on the exerciser for three months. After that time, one test subject’s weight dropped from 100 to 91 kilograms; the other’s decreased from 67 to 63 kilograms. As a synergistic effect, the strength of the muscles used for maintaining good posture increased, which improved the subjects’ hunchbacked condition. We were pleased to observe that when the prototype exerciser was kept under the test subjects’ desk, they spontaneously placed their feet on the pedaling steps and began pedaling every time they sat at their desk. Even now, after one year, the subjects have maintained their reduced weight because they can exercise while in the office. To convert office sedentary time to health-promoting time, we believe we have successfully developed a prototype exerciser that achieves both effectiveness and continuity. We plan to continue validating the effectiveness of this prototype exerciser.

Future Research Goals

Through this research, we felt better in ourselves while exercising. On the basis of that experience, we plan to continue our research next by focusing on the following question: how can we help people’s bodies and minds become healthier while sitting? We also plan to conduct research toward helping people improve their posture the longer they sit as well as alleviating lower back pain and tight shoulders. We aim to work on technologies that will predict human behavior using ideas obtained from our research. We hope to report our results on this website in the future.

  • Photos of authors and research members Eisuke Aoki, Ph.D. Project Manager Robotics Group No.1 R-Frontier Div. Frontier Research Center. The author is interested in developing new businesses in medical and healthcare field and is promoting human research using needs-driven development and design thinking.Photos of authors and research members Eisuke Aoki, Ph.D. Project Manager Robotics Group No.1 R-Frontier Div. Frontier Research Center. The author is interested in developing new businesses in medical and healthcare field and is promoting human research using needs-driven development and design thinking.
    Author (center back) and research team

Author: Eisuke Aoki, R-Frontier Division, First Robotics Group, Project Manager, PhD (Science); interested in developing new businesses in medical and health-care fields; completed the Japan Biodesign Fellowship Program (2017–2018); promoting design-thinking-based and need-driven research on humans. As of 2021, the author has 49 patents registered under his name.

References

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岡 浩一朗, 杉山 岳巳, 井上 茂, 柴田 愛, 石井 香織, Neville OWEN: 特別報告 座位行動の科学―行動疫学の枠組みの応用, 日健教誌 第21巻 第2号 2013年より
2
van der Ploeg HP, Chey T, Korda RJ, et al. Sitting time and all-cause mortality risk in 222,497 Australian adults. Arch Intern Med 2012:172:494-500
3
Owen N, Healy GN, Howard B, et al. Too much sitting: Health risks of sedentary behaviour and opportunities for change. Research Digest published quarterly by President's Council on Fitness, Sports & Nutrition 2012;13:1-11
4
Dunstan DW, Howard B, Healy GN, et al. Too much sitting--A health hazard. Diabetes Res Clin Pract2012, 97,368-76.
5
Thorp A, Owen N, Neuhaus M, et al. Sedentar ybehaviors and subsequent health outcomes: a systematic review of longitudinal studies.1996-2011, Am J Prev Med 2011;41:207-215
6
Bauman AE, Ainswor th B., Sallis J, et al. The descriptive epidemiology of sitting: A 20-country comparison using the International Physical Activity, Questionnaire(IPAQ). Am J Prev Med 2011;41:228-235
7
Ng SW, Popkin BM. Time use and physical activity: a shift away from movement across the globe. Obes Rev. 2012 Aug;13(8):659-80. doi: 10.1111/j.1467-789X.2011.00982.x. Epub 2012 Jun 14. PMID: 22694051; PMCID: PMC3401184.

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