In recent years, there has been a sharp increase in the number of elderly people in South Korea; this has led to rising costs and concerns on the quality of physical therapy treatment involving rehabilitation robotic devices. Therefore, the government has asked academia to expand its research scope to evaluate the usability of these devices. Hence, this study aimed to identify the major factors influencing the usability of a rehabilitation robotic device for lower limbs and the reasons for involving several diverse user groups for a more comprehensive evaluation. To measure usability as perceived by three primary user groups of user experience (UX) professionals, rehab professionals, and lay people, this study collected 196 survey. The results of an EFA showed that among three general quality factors and five device specific factors, visual pertinence, use confidence, and safety were the critical factors influencing usability, and the results of ANOVA offered that there was discrepancy in the influential factors, namely visual pertinence, transferring, and holding the body. These findings indicate that the necessity of employing a posture-centered approach and multiple user groups in assessing the usability of rehabilitation devices. Given these findings, it is suggested that the industry and design community should move toward implementing a more explorative perspective to enable a more human-centered and posture-concerned approach to provide better usability to the diverse users of medical devices.

Recognizing modern society’s multiple risks, this study examines single-use plastic water bottles at the intersection of environmental degradation and societal carelessness for the elderly. While prioritising economic profits and plastic waste, we have neglected bottles’ typical poor openability for older people. Thus, we evaluated the openability of bottles with environmentally friendly and socially inclusive designs in South Korea by comparing older and younger adults’ experiences. Integrating different attributes than existing studies that analyse opening torque or one-handed opening, the test results show that older adults experience the poorest two-handed openability when bottles have both a weight thickness lower than 14.42 g and an easily squeezable bottle structure. In South Korea, companies advocate eco-friendliness by valuing lighter weight with less plastic and support user-friendliness by adopting easily squeezed sidewall patterns, while the industry maintains broad opening torque regulations; however, we show this combination exceeds older users’ capabilities. That is, for openability, bottles need to keep a weight thickness greater than 12 g, abandon easily squeezed sidewall patterns or reduce the opening torque regulation range to 100 N-cm. These socially favourable but ecologically adverse measures will be sustainable when the efficient linear economy transitions to an effective circular economy.