Recently, Difficulties and problems in the daily lives of the elderly have recently emerged. Older people lose muscle strength as aging progresses. The Decrease in muscle strength is caused by aging as age increases and less physical activity. As you get older, your lower body muscles weaken, leading to decreased muscle strength, which leads to falls. The need to support the elderly''s self-reliance in their homes is being emphasized as the number of elderly single-person households and elderly couple households increases along with the increase in the elderly population. In order to enable the elderly to live on their own, they must basically ensure smooth movement. In this study, a lift-chair was developed to reduce safety accidents in their daily lives of elderly people with reduced muscle strength as the importance of health and well-being of the elderly was emphasized by the increase in the elderly population. In addition, muscle strength characteristics of the elderly and those in their 20s were compared and analyzed when using lift-chairs. The lift-chairs used are chairs that can be raised and lowered and designed to reach the floor in full descent. The electromyography was measured to compare the near-term use of lift-chairs to those in their 20s. As a result, the elderly had higher use of lower limb muscles compared to young subjects. It was judged that the upper and lower extremities were difficult to move due to the characteristics of the elderly with reduced muscle strength and that the upper and lower limbs were used simultaneously to complete the movement. In addition, the body pressure of users by height was analyzed during the lift. As a result, the distribution of body pressure by height and the timing of dispersion were known, and the results of the center of gravity shift showed basic data for safe design. Finally, a usability evaluation was conducted. The usability assessment was conducted with a universal design PPP assessment and a QUEST assessment. Through this, opinions on developed products were collected, and results on satisfaction compared to importance were obtained quantitatively. The results showed the characteristics of everyday motion of the elderly for the development of lift-chairs and can help improve design, function, etc. in the later development of lift-chairs.