It is most important to reach the maximum bone density in the childhood period to prevent developing osteoporosis; it is widely known that increased body weight has a positive correlation with bone density and that even though both the fat mass and lean mass have a significant impact on bone density, the latter mass has more importance for adults. Therefore, the study analyzed to identify the relationship between bone density and both fat mass and lean mass of Korean adolescents. Subjects were chosen among 21,303 people from the Korea National Health and Nutrition Examination Survey (KNHNES) between 2008 and 2011 that took a bone density checkup; as a result, 1454 teenagers aged between 12 and 18 were selected. Data analysis was performed in SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA) following the KNHNES and the weighted complex sample analysis was conducted; body fat mass and lean mass were divided into quintile groups, and to figure out the differences in bone density that were analyzed in six models adjusted by body weight (kg) and walking (yes/no), muscle strengthening exercises (yes/no), nutrition (intake of ca (g), and serum vitamin D (ng/mL)). Then, the generalized linear model (GLM) and trend test were conducted for each gender with a significance level of 0.05. The bone density differences of fat mass and lean mass were analyzed. The result of Model 6 considering all correction variables is as follows; in the case of male adolescents, the total femur and lumbar spine showed a significant difference (F = 13.120, p < 0.001; F = 12.900, p < 0.001) for fat mass, and the trend test showed that the figures significantly decreased (β = −0.030, p < 0.001; −0.035, p < 0.001). Meanwhile, for lean mass, the total femur and lumbar spine had a significant difference (F = 16.740, p < 0.001; F = 20.590, p < 0.001) too, but the trend test showed a significant increase (β = 0.054, p < 0.001; 0.057, p < 0.001). In the case of female adolescents, the lumbar spine (F = 3.600, p < 0.05) for lean mass showed a significant difference, and it also significantly rose in the trend test too (β = 0.020, p < 0.01). To sum up the results, for male adolescents, the bone density differences for fat mass (FM) and lean mass (LM) all had significant differences, but for female adolescents, only the lumbar spine for LM showed such a result. Meanwhile, both genders showed that LM had a more positive impact on bone density than FM.

This study aims to examine the effect of a 12-week intradialytic exercise program on patients’ blood indices, physical performance, and quality of life. Forty-six outpatients who were diagnosed with end-stage renal failure by a nephrologist and received hemodialysis therapy for six months or longer were recruited. The data were analyzed using SPSS and Kruskal-Wallis test was employed to analyze the continuous variables. Among blood indices, Hematocrit decreased significantly after aerobic and complex exercise; hemoglobin dropped only after complex exercise; P and Ca×P increased for a considerable amount only after complex exercise, but the postexamination results show no significant difference. As for physical performance, sit-to-stand (STS)-5 decreased with resistance and complex exercise (p < .01), while there was a significant increase in STS-30 after aerobic, resistance, and complex exercise (p < .01). 6-minute walk test (MWT) grew significantly in all groups (p < .01), but alongside gait speed, and grip strength, it diminished significantly in the non-exercise group (p< .05). When it comes to SF-36, there was a significant rise in the physical component score (PCS) (p< .01) with resistance and complex exercise. In the meantime, mental component summary (MCS) went up significantly after all types of exercises (p < .01). In contrast, Beck depression inventory (BDI) showed a significant decline only with complex exercise (p < .01). To sum up, this study suggests intradialytic complex exercise appears to be effective in enhancing Short Form (SF)-36 and BDI as well as physical performance, which is why we recommend this type of complex exercise program for hemodialysis patients.

The purpose of this study is to examine changes in physical activity in Korean society, after the outbreak of COVID-19. Method This study was conducted using the Korean Community Health Survey conducted in 2019 and 2020. Subjects that have been diagnosed with hypertension and diabetes were excluded; a total of 355,914 cases were involved for analysis. In terms of the analysis method, General Linear Model (GLM) was conducted to examine the changes in physical activities in 2019 and 2020 depending on the presence of a spouse, educational status, and economic activities. In addition, the GLM was adopted to divide the subjects by gender and age, and analyze their physical activity changes in 2019 and 2020 with spouse presence, educational status, and economic activities as adjusted variables. Result In terms of Koreans, those without a spouse, high educational attainment, and economically inactive were less engaged in physical activities. Differences were found in subjects regarding moderate-intensity physical activities after social distancing following the spread of COVID-19. Senior females without a spouse, both males and females with low educational attainment, economically inactive adult females, and economically active senior males showed a greater drop in physical activities. For walking hours, both adult males and females without a spouse, adult females with all educational attainment level excluding elementary and middle school graduates, and economically inactive adult males and females also showed a downward trend. Conclusion The study recommends that people develop a strategy to increase their post-outbreak physical activity, taking into account the sociodemographic.

Taekwondo is a Korean martial art and international sport, and its psychosocial benefits for its trainees have been studied extensively. This review aims to systematically assess and meta-analyze the effects of Taekwondo training on sociality, character, etiquette, and school life adjustment. We searched the RISS, NDSL, and KISS electronic databases between January 1985 and December 2019. We also included gray literature, such as theses, in addition to peer-reviewed articles. R software (version 3.6.2, R Core Team, Vienna, Austria) was used to synthesize the effect sizes and perform moderation analyses. Twenty-eight studies (24 cross-sectional and four intervention studies) were included in the final meta-analysis. Significant positive effects of Taekwondo training were found on sociality (MD = 0.266, 95% CI: 0.191 to 0.341), character (MD = 0.446, 95% CI: 0.331–0.560), etiquette (MD = 0.562, 95% CI: 0.500–0.624), and school life adjustment (MD = 0.308, 95% CI: 0.195–0.421). Overall, the findings of this meta-analysis support that Taekwondo can have a positive impact on the psychosocial factors of trainees. Due to several limitations discussed, well-designed RCTs and multiple levels of Taekwondo intervention studies should be conducted in future research to validate the current findings.

The tendency of misperceiving one’s body image was found to be higher among those at normal body mass index (BMI). Thus, the present study aims to provide basic data to seek solutions for ideal physical activities and right body image perception by comparing health-related behaviors of women at normal BMI. Among the 39,225 respondents from the Korea National Health and Nutrition Examination Survey (KNHNES) conducted from 2013 to 2017, 10,798 adult women with World Health Organization (WHO) BMI Classifications of 18.5 ≤ BMI < 25 (Asia-Pacific) were considered, from which pregnant and breast-feeding women and women whose body image perception was not identified were excluded, leading to a total of 9288 women. Data were analyzed utilizing SAS ver. 9.4 for frequency analysis, cross tabulation, GLM (generalized linear model), and logistic regression analysis with complex samples design, in conformity with the guidelines of the KNHNES. The results showed that approximately most (87.6%) of adult Korean women misperceived their body image. Misperception of body image was related to inappropriate health-related behaviors such as smoking, insufficient sleeping, and excessive body weight management; those who had underestimated their body image (≤64 odds ratio (OR) (0.718 (confidence interval (C.I.) 0.594–0.866))) carried out fewer health-related behaviors, while women aged 65 or above engaged in more health-related behaviors when they perceived themselves as obese (OR 1.683 (C.I. 1.260–2.248; overestimation)). To sum up, it was found that lack of health management, inappropriate body weight control, and health-related behaviors are related to body image misperception compared with real BMI. As such, it is necessary to have educational programs to encourage building proper perception of one’s body image and body weight, and to carry out health-related behaviors.