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Background/Objectives: During the COVID-19 pandemic, children in Japan were restricted from sports and outdoor activities. Regular physical activity is essential for healthy growth and development in children, with recommendations advocating for activities such as strength training. However, the long-term effects of the restrictions have not been fully investigated. This study aimed to evaluate the effectiveness of an "exercise class", specifically a dance program, designed to improve motor function in elementary school children affected by the coronavirus disease 2019 (COVID-19) pandemic, which may have compromised their motor function. Methods: The dance program was developed by a sports science teacher, a professional dancer, and a physical therapist, and it was evaluated in a community-based participatory study. Trained dance instructors conducted one-hour dance sessions in a medical center, held once a week for two months from June to August 2023. A physical therapist and dance instructors led the elementary school children. Outcome measures included grip strength, lower extremity muscle strength, back muscle strength, dynamic balance function during movement, physical activity time, and body fat percentages. Descriptive statistics were used for analysis. Results: Twenty-four children aged 6–9 years participated in the exercise class over a two-month period. Improvement was observed in grip strength, lower extremity muscle strength, and dynamic balance function during movement. However, physical activity time, body fat percentages, and back muscle strength did not change. Conclusions: The results indicated a significant improvement in motor skills. Dance is an inexpensive program that elementary school children can enjoy while improving their motor skills. [ABSTRACT FROM AUTHOR]

Low-back pain is common among school-aged children. Decreased trunk flexibility in childhood influences low-back pain in adulthood. Previous studies examining the association between low-back pain and trunk flexibility in children are insufficient. Examining this association among elementary school children may help to better understand trunk flexibility in children with low-back pain and to modify the management of inflexibility. Therefore, this study aimed to identify the prevalence of low-back pain and its relationship with physical function among elementary school students. School-aged children aged 6–12 years were recruited in Japan between May 2018 and March 2023. Fingertip-to-floor distance, back muscle strength, pelvic tilt angle during gait, and the visual analog scale for low-back pain were measured. In addition, factors independently related to low-back pain were determined through logistic regression analysis. Low-back pain was reported in 9.6% of the 394 participants (boys, 191; girls, 203). All children with low-back pain presented with back pain when they moved; however, the pain was non-specific. Logistic regression analysis showed that the fingertip-to-floor distance was an independent risk factor for low-back pain (odds ratio, 0.921; p = 0.007). The odds ratios calculated in the logistic regression analysis confirmed that low-back pain frequency increased as the fingertip-to-floor distance decreased. The risk of low-back pain was associated with inflexibility, regardless of sex and muscle strength. These findings suggest that children with low-back pain must increase their trunk and lower extremity flexibility. [ABSTRACT FROM AUTHOR]

Carcinogenicity and chronic toxicity of 1,4-dichloro-2-nitrobenzene (DCNB) were examined by feeding each group of 50 F344 rats and 50 BDF1 mice of both sexes a DCNB-containing diet at a concentration of 0 (control), 320, 800 or 2,000 ppm (w/w) for 2 yr. In rats, incidences of hepatocellular adenomas and carcinomas and their combined incidence were increased in the 2,000 ppm-fed males, together with increased incidence of basophilic cell foci in the 800 and 2,000 ppm-fed males. A dose-related increase in combined incidences of renal cell adenomas and carcinomas was noted. Incidence of Zymbal gland adenomas tended to increase in the 2,000 ppm-fed males. In mice, incidences of hepatocellular adenomas in the 800 and 2,000 ppm-fed females and hepatocellular carcinomas in the 2,000 ppm-fed males and in the 800 and 2,000 ppm-fed females were increased. Incidence of hepatoblastomas was increased in all DCNB-fed males and in the 2,000 ppm-fed females. Signs of chronic toxicity were characterized by centrilobular hypertrophy of hepatocytes with nuclear atypia in mice, increased relative liver weight in rats, a dose-related increase in incidences of chronic progressive nephropathy with advanced grades of severity in male rats, and decreased hemoglobin concentration and hematocrit accompanied by increased bone marrow hematopoiesis in female rats. Carcinogenic activity of DCNB was evaluated for the three different tumors, and sensitive signs of the chronic toxicity were dis-