Specialized guidelines are required for the health behaviors of vulnerable populations such as children. This is especially true during the COVID-19 pandemic, wherein major lifestyle changes have occurred, especially among young children. The present study aims to use longitudinal data to understand changes in the physical activity, screen time, sleep, and mental health of preschoolers in Japan during the COVID-19 pandemic, compared to pre-pandemic period. Subjective and objective measures were used to assess the variables of interest longitudinally. It was found that physical activity, adherence to WHO-recommended screen time, and prosocial behaviors decreased significantly. On the other hand, sedentary time and hyperactivity increased. Our results are consistent with findings from other countries. The implications with respect to outdoor playtime, screen-time in the context of online learning during the pandemic, and the effects of parents’ mental health on preschool-aged children are discussed.

The interactions between movement behaviors (physical activity, screen time, and sleep) affect the health of preschool children. Therefore, we examined the status of adherence to combinations of 24-hour movement guidelines (24-h MG) in Japanese preschool children and determined the associations between overweight/obesity and adherence to these 24-h MG. This cross-sectional study was conducted with 421 children aged 3–5 years (216 boys and 199 girls) living in the northeastern region of Japan. To evaluate the 24-h MG, physical activity over one week was measured using a three-axis accelerometer. For screen time and sleep duration, a questionnaire survey was conducted. Children who failed to meet all the 24-h MG had a higher probability of overweight/obesity than those who met all the 24-h MG (odds ratio 1.139, 95% confidence interval: 1.009, 1.285). The percentage of adherence to the 24-h MG was 91.6% for physical activity, 82.5% for sleep duration, and 33.7% for screen time, and only 21.5% of the children adhered to all three areas of the guidelines. Our findings have important implications for developing public health policies and effective intervention programs for preschool children.

Blood flow restriction training (BFRT) is a new method for promoting muscle growth and improving muscle function, even with relatively low-intensity exercise. BFRT on patients with obesity has not been extensively studied. This study aimed to analyze the effects of cycling at 40% of maximum oxygen uptake (VO₂max) combined with BFRT on body composition and serum biomarkers among college students with obesity. This pilot study included thirty-seven male college students with obesity aged 18–22 years (experimental group (EG): n = 18; control group (CG): n = 19). The EG conducted 40% VO₂max cycling combined with BFRT activities and the CG conducted 40% VO₂max cycling without BFRT two times per week for 12 weeks. Our results showed that in EG, there were significant differences in weight, thigh skinfold thickness (TS), waist circumference, abdominal skinfold thickness, fat mass, body fat percentage, body mass index and glucose (GLU), total cholesterol (TC), triglyceride, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels before and after the experiment (p < 0.05, p < 0.01, and p < 0.001). After the experiment, TS, GLU, TC, HDL-C, and LDL-C in EG were significantly different than those of the CG (p < 0.05, p < 0.01, and p < 0.001). Together, our results demonstrate that cycling at 40% VO₂max combined with BFRT may improve body composition and blood lipid profile of male college students with obesity. Our findings have important implications for those who cannot perform moderate- and high-intensity exercises.

Gross motor locomotion is the basis of various sensory motor locomotion. Interventions helping preschoolers develop gross motor skills (GMS) could provide a solid foundation for complex motor skills. This study analyzed a table tennis physical activity program’s influence on preschoolers’ GMS development with 104 preschoolers (experimental group (EG): N = 52, 25 boys, 27 girls; control group (CG): N = 52, 25 boys, 27 girls). The EG conducted table tennis physical activities three times per week for 12 weeks. Preschoolers’ GMSs were assessed using the Test of Gross Motor Development (second edition). After 12 weeks, both the male and female EGs had significantly improved scores for GMS, locomotor subtest, gallop, hop, leap, slide, object control subtest, strike a stationary ball, stationary dribble, catch, overarm throw, and underhand roll (p < 0.05, p < 0.01, p < 0.001). The female EG also showed significant improvement for the run, horizontal jump, and catch in the post-test. Both the male and female EGs significantly outperformed the control group in their post-test scores for GMS, locomotor subtest, object control subtest, strike a stationary ball, overarm throw, and underhand roll (p < 0.05). The female EG also showed significant differences in slide scores (p < 0.05). Therefore, table tennis physical activities can promote preschoolers’ GMS development, especially object control skills. The research results provide an empirical basis for preschoolers’ physical education. Meanwhile, our findings have important implications for preschoolers’ GMS development and table tennis’ popularization in Chinese kindergartens.

Children aged 3–6 years (preschool children hereafter) are in a critical and sensitive period of developing fundamental movement skills (FMS). While appropriate measurement tools can accurately evaluate their FMS development, such a scale is lacking in China. In this study, a suitable scale for measuring the FMS of preschool children in China was developed by combining process- and results-oriented evaluation methods. The subjects of this cross-sectional study included 21 experts and 358 preschool children (188 boys and 170 girls). Based on a literature review, items suitable for measuring the FMS of preschool children in China were selected, and the final measurement scale includes 12 items in three dimensions: physical locomotion skills, object control skills, and physical stability skills. After a battery of tests to assess its suitability, including inter-rater reliability, test/retest reliability, homogeneity, and construct validity, we find that the proposed measurement scale has good reliability, validity, and sensitivity. This scale reflects the development level of the FMS of preschool children in China and can be used to monitor the FMS of this population in the future.

Specialized guidelines are required for the health behaviors of vulnerable populations such as children. This is especially true during the COVID-19 pandemic, wherein major lifestyle changes have occurred, especially among young children. The present study aims to use longitudinal data to understand changes in the physical activity, screen time, sleep, and mental health of preschool-aged children in Japan during the COVID-19 pandemic, compared to pre-pandemic periods. Subjective and objective measures were used to assess the variables of interest longitudinally. It was found that physical activity, adherence to WHO-recommended screen time, and prosocial behaviors decreased significantly. On the other hand, sedentary time and hyperactivity increased. Our results are consistent with findings from other countries. The implications with respect to outdoor playtime, screen-time in the context of online learning during the pandemic, and the effects of parents’ mental health on preschool-aged children are discussed.