RESUMO
Objective@#To investigate the effects of after school exercise service (referred to as the "after school ES") on physical health, so as to provide evidence for possible beneficial effect of after school ES.@*Methods@#Students in the fourth grade of primary school were recruited from September 2021 to July 2022 in Changsha City and divided into the control group ( n =220) and the after school ES group ( n =220). The control group only participated in the regular physical education activities of the school. The after school ES group received after school ES for one academic year, 4 times a week, 40-50 minutes per time, for a total of 32 weeks. Body shape indicators such as height, weight and percentage of body fat, as well as physical fitness indicators such as 50 meter running, grip strength and progressive aerobic cardiovascular endurance run (PACER) were measured in September to October 2021 and June to July 2022, respectively. Independent sample t-test, Chi square test and two factors repeated measurement analysis of variance were used for statistical analysis of the data.@*Results@#After one academic year, compared with the control group [(13.52±2.30)kg], muscle mass of primary school students in the after school ES group [(13.76±2.32)kg] significantly increased, while waist to hip ratio [(0.95±0.16)] and percentage of body fat [(20.17±7.43)%] significantly decreased compared to the control group [(1.01±0.21), (22.02±12.34)%]( F=330.70, 6.85, 4.33, P <0.05). The proportion of overweight and obesity in after school ES group decreased significantly from 19.5% to 12.3% ( χ 2=4.35, P <0.05). Compared with the control group, the scores of 50 meter running [(10.00±1.06, 10.21±0.83)s], 1 minute sit up [(33.25±8.24, 30.76±9.34)times], sitting and flexion [(14.53±7.50, 8.59±6.32)cm], 1 minute rope skipping [(125.01±30.50, 115.97±32.09)times], eyes closed and single legged standing [(30.00±34.72, 25.72±23.82)s], selective response time [(635.66±91.72, 652.79±120.42)ms] and VO 2max [(45.31± 1.02 , 43.67±0.85)mL/(kg〖 ·min)] in the after school ES group were significantly improved, with statistical significance ( F= 5.32 , 443.14, 97.23, 814.07, 36.49, 6.11, 396.91, P <0.05).@*Conclusions@#After school ES can improve body shape of primary school students, reduce the risk of overweight and obesity and enhance physical fitness. It is recommended that schools should appropriately increase after school ES to promote physical fitness of students.
RESUMO
Objective: To explore physical shape changes in preschool children from 2000 to 2020, and forecast development trends over the next 10 years. Method: The grey GM (1,1) prediction model was used to fit the physical shape indicators of preschool children in China from 2000 to 2020, and then the longitudinal change trend of physical shape was compared and analyzed. Finally, the development trend of physical shape in China in 2025 and 2030 was predicted. Results: (1) During the period from 2000 to 2020, the height, weight and chest circumference of Chinese preschool children all increased rapidly. Specifically, the weight of male and female children increased by 1.8 kg and 1.6 kg, their chest circumference increased by 1.6 cm and 1.5 cm, respectively, and both their heights increased by 3.6 cm. Among these indicators, the older the age, the greater the growth rate. It is expected that all the indicators will continue to grow rapidly over the next 10 years, but the growth rate will slow. (2) From 2000 to 2020, the growth rate of weight was higher than that of height, and BMI showed an increasing trend. The obesity detection rates in boys and girls increased by 5.6 and 2.8%, respectively. Over the next 10 years, the incidence of obesity is expected to increase by 3.8% in boys and 2.8% in girls. (3) Improvement in the growth and development of preschool children in China has a certain correlation with the rapid growth of China's economy,less physical activity, education and other factors. Conclusion: Over the past 20 years, the growth and nutritional status of Chinese preschoolers have improved dramatically, but overweight and obesity remain. Overweight and obesity rates are expected to continue to increase rapidly over the next 10 years, particularly among boys, and effective measures should be taken to control the obesity epidemic.
