The purpose of this study is to provide essential data for the establishment of education and policy for the formation of healthy lifestyles of adolescents in the future by analyzing the patterns of changes in society due to the prolonged COVID-19 in the physical activities, sleeping habits, obesity, and mental health of Korean adolescents. To this end, a total of 147,346 adolescents were selected and analyzed according to the purpose of the study in the 2018 (14th), 2019 (15th), and 2020 (16th) raw data of the “Youth Health Behavior Online Survey,” an annual national approval statistical survey conducted by a Korean government agency. The study examined changes in the physical activity, obesity, sleep, and mental health of Korean adolescents due to COVID-19. The physical activity rate of Korean adolescents in 2019 decreased by 5.3% from 2018. In addition, the physical activity rate in 2020 decreased by 2.1% compared to 2019. It was found that physical activity steadily decreased (p < 0.001). The obesity rate increased by 0.9% in 2019 compared to 2018 and by 1.8% in 2020 compared to 2019. Although the obesity rate steadily increased, it was found that it was accelerated due to COVID-19 (p < 0.001). Looking at the subjective sleep satisfaction rate of Korean adolescents, in 2019, it was 0.1% lower than in 2018, while in 2020, when COVID-19 began, it increased by 3.5% compared to 2019. It was found that satisfaction with sleep increased after COVID-19. Finally, the mental health characteristics of Korean adolescents by year were divided into stress and depression. Stress decreased by 1% compared to 2019 and 2018 and by 6.2% compared to 2020 and 2019. Depression increased by 1% in 2019 compared to 2018 and decreased by 3.4% in 2020 compared to 2019. In other words, stress and depression decreased after COVID-19. In 2020, when COVID-19 occurred, it was confirmed that there was a change in the health behavior of adolescents compared to 2018 and 2019. Therefore, active responses from schools, families, and communities are required to foster healthy lifestyle habits in social changes such as COVID-19.

As the competition among businesses intensifies and customer needs become increasingly diverse and complex, the need for personalized service has emerged. This study examines the effect of technology-based self-service (TBSS) characteristics of a Taekwondo academy on perceived value and intention to use continuously. The study sample consisted of masters managing a Taekwondo academy who had prior experience with TBSS. A total of 188 responses were collected using an online questionnaire. The collected data were analyzed using SPSS 23.0 and AMOS 23.0. The results demonstrated the following: first, among the sub-factors of TBSS characteristics, reliability, usefulness, and enjoyment were found to affect the perceived value positively; second, among the sub-factors of TBSS characteristics, usefulness and ease of use positively affected the intention to use continuously; and finally, the perceived value was found to affect the intention to use continuously positively. This study provides practical implications for more efficient use of the TBSS provided by a Taekwondo academy by discovering the relationship between the TBSS configuration of the Taekwondo academy, perceived value, and intention to use continuously.