Jaesoo Hong

Evaluation of Seat Pan Inclination During Sit-to-stand for Development of Elderly Lifting-chair

Objective: The aim of this study is to set the design direction of the lift chairs tilting seat for development. Background: Great attention has been shown to the development of senior friendly product, because of increasing elderly population rapidly in Korea. Therefore, we need to study on sit-to-stand(STS) motion of elderly systematically for developing lift chair that is one of senior friendly products. Method: In this study, we analyzed joint moment(knee, hip) and muscle activity (Erector spinae, Rectus femoris, Vastus lateralis) on STS motion of elderly(female, 60~70: 7) and young people(female, 20~30: 7) using 3 dimension motion capture camera, force plate, wireless EMG. Results: The results of muscle activity showed a similar trend but the results of joint moment were a lot of differences between the young and the elderly. Conclusion: The results of knee joint moment suggest the angle(10~30deg)-adjustable seat that can be better than to find the optimal seats angle. Application: The method and results of this study are expected to develop senior friendly product and verification as well as be available to various application.

Anthropometric Analysis and Usability Evaluation of Four-wheeled Walker

In this study, anthropometric analysis and usability evaluation for four-wheeled walker were carried out and then ergonomics design guidelines were proposed. In anthropometric analysis, design factors of four-wheeled walker were firstly identified and anthropometric design guidelines were made using Korean human scales. Design suitability for two typical four-wheeled walkers was analyzed in based on anthropometric design guidelines. Usability evaluation for two typical walkers was also performed through observation method and expert evaluation. Several usability problems were identified and design solutions were proposed for the design improvement of four-wheeled walker. Finally a design model of four wheeled walker considering analysis results was proposed.

Optimized balance rehabilitation training strategy for the elderly through an evaluation of balance characteristics in response to dynamic motions

Balance is important in daily activities and essential for maintaining an independent lifestyle in the elderly. Recent studies have shown that balance rehabilitation training can improve the balance ability of the elderly, and diverse balance rehabilitation training equipment has been developed. However, there has been little research into optimized strategies for balance rehabilitation training. To provide an optimized strategy, we analyzed the balance characteristics of participants in response to the rotation of a base plate on multiple axes. Seven male adults with no musculoskeletal or nervous system-related diseases (age: 25.5±1.7 years; height: 173.9±6.4 cm; body mass: 71.3±6.5 kg; body mass index: 23.6±2.4 kg/m2) were selected to investigate the balance rehabilitation training using customized rehabilitation equipment. Rotation of the base plate of the equipment was controlled to induce dynamic rotation of participants in the anterior–posterior, right-diagonal, medial–lateral, and left-diagonal directions. We used a three-dimensional motion capture system employing infrared cameras and the Pedar Flexible Insoles System to characterize the major lower-extremity joint angles, center of body mass, and center of pressure. We found statistically significant differences between the changes in joint angles in the lower extremities in response to dynamic rotation of the participants (P<0.05). The maximum was greater with anterior–posterior and medial–lateral dynamic rotation than with that in other directions (P<0.05). However, there were no statistically significant differences in the frequency of center of body mass deviations from the base of support (P>0.05). These results indicate that optimizing rotation control of the base plate of balance rehabilitation training equipment to induce anterior–posterior and medial–lateral dynamic rotation preferentially can lead to effective balance training. Additional tests with varied speeds and ranges of angles of base plate rotation are expected to be useful as well as an analysis of the balance characteristics considering a balance index that reflects the muscle activity and cooperative characteristics.

Case Study on Developing an Elderly Automatic Shower System

Objective: The aim of this study is developing an elderly automatic showering system by optimizing nozzle position and angle of water injection on ergonomics approach. Background: The elderly living in nursing home or hospital were increased by an aging population. Helping the elderly on showering is so hard. In addition, the existing showering/bathing systems are not effective because shower pattern of the elderly and washed range of nozzle were not considered. Method: Firstly, basic specification were determined by anthropometric approach. Secondly, position of nozzle and angle of water injection were determined through observation of elderly behavior on showering. And, finally, they were optimized by washing test and showering simulation. Results: On showering importance of body parts were able to analysis through observation of elderly behavior. The position of nozzle and angle of water injection was able to optimize by showering simulation. The automatic showering system was developed by considering their results. Conclusion: The most important technology of developing a showering system is the determining position of nozzle and angle of water injection, number of nozzle. It was developed by applying its results through user centered-research. Application: The user centered-research of developing products was able to apply directly to develop automatic bath, showering products etc. Further more it was available to apply senior friendly products.

Comparison of Muscle Activity in Young People and Seniors During Hip Adduction and Abduction Movements According to Backrest Angle

The purpose of this study was to analysis patterns of changes in muscle activity and subjective assessment at various backrest angles during lower-limb rehabilitative exercises across different age groups to determine the appropriate backrest angles during exercise. Elderly people experience difficulties in normal walking due to their reduced muscle strength, balance, and flexibility caused by aging. Although equipment has been developed for muscle strengthening and rehabilitative exercises, studies on exercise postures and chair backrests are relatively insufficient. In this study, participants performed hip adduction and abduction rehabilitative exercises. Electromyogram test and a subjective questionnaire survey were conducted for 15 healthy adults in their 20s and 4 healthy elderly persons aged 65 years or older. Differences in muscle activity level according to backrest angle were observed. A significant difference in angle preference was found between young and old participants (p < 0.05). Results of this study may be used as ergonomic data to develop rehabilitative exercise equipment.

Development on the Auto Showering System Concerning Bed Type for the Elderly: Focusing on Nozzle Optimization

Objective: The aim of this study is to design an auto showering system regarding bed type for old people or bedridden patients. Background: The rapid growth concerning the aging population leads to an increase in elderly bedridden patients living in senior care centers and hospitals where care givers have difficulty bathing older people with limited mobility. Method: In this study, a showering equipment for experiment was based on anthropometric and researching existing products. The nozzle position was optimized by showering tests and simulations using showering equipment. Results: The problems regarding the existing products were analyzed and the nozzle position was optimized through showering tests. The number, position, and spraying angle of the nozzle were optimized through showering simulations. The automatic showering system concerning bed type was designed by considering their results. Conclusion: When designing an automatic showering system, the most important design element involves determining the position of nozzle and angle of water injection and the number of nozzles. The system was developed by applying the results through user centered-research. Application: The user centered-research for developing products was applied directly in order to develop automatic baths, showering products etc. Furthermore, it was also available to be applied towards senior friendly products.