Component analysis of relationship between 24 hour movement behavior and physical fitness in college students / 中国学校卫生

Objective@#To explore the relationship between 24 hour movement behavior and physical fitness in college students, so as to provide a reference for physical fitness interventions for college students.@*Methods@#A survey was conducted from September 23 to November 12, 2022, involving 342 college students selected from one comprehensive college among Shanghai City, Hubei Province and Zhejiang Province. Accelerometers were used to measure 24 hour movement behavior, and programs specified in the National Physical Fitness Standards for Students (2014 revision) were used to evaluate physical fitness. Compositional linear regression was used to analyze the association between 24 hour movement behavior and physical fitness. The effects of compositional isotemporal substitution of 24 hour movement behavior on physical fitness were also examined.@*Results@#The geometric means for sleep, sedentary behavior, light physical activity (LPA), and moderate to vigorous physical activity (MVPA) were 515.89, 678.88 , 196.30, 48.92 min/d, respectively, and the comprehensive physical fitness score was (73.09±8.55). The proportion of participants who passed the fitness test was 72.51%. Overall, 20.76% had excellent or good scores, whereas 6.73% failed. Compositional linear regression indicated that physical fitness was significantly positively associated with MVPA ( β =2.55) and LPA ( β = 5.88 )( P <0.05), but no significantly associated with sleep ( β =-5.18) and sedentary behavior ( β =-3.24)( P >0.05). Isotemporal substitution indicated that reallocation of 15 minutes from sleep and sedentary behavior to MVPA resulted in a 0.71 and 0.64 point increase in physical fitness, respectively. Similarly, reallocating the same duration to LPA led to a 0.50 and 0.43 point increase in physical fitness, respectively. Dose response analysis revealed that the mutual substitution of LPA with sedentary behavior and sleep had symmetry, whereas the mutual substitution of MVPA with sedentary behavior and sleep had asymmetry. The effectiveness of replacing sleep or sedentary behavior with MVPA in improving physical fitness decreased with increasing allocation time, whereas the adverse effects of replacing MVPA with sleep or sedentary behavior increased with increasing allocation time.@*Conclusion@#In the context of 24 hour movement behavior, increasing the time spent on LPA and MVPA is beneficial for physical fitness among college students. It should be recommend that college students actively transition from sedentary behavior to engaging in physical activity, with a particular emphasis on incorporating MVPA.

Relationship between 24 hour movement behavior and obesity indicators in children and adolescents / 中国学校卫生

Objective@#The method of compositional data analysis was used to explore the relationship between 24 hour movement behavior and obesity indicators, and to examine the difference of quantitative effect on obesity indicators when one behavior replaced another behavior, so as to provide specific movement behavior advice for weight control in children and adolescents.@*Methods@#In June 2021, 231 students from eight classes in a primary school and a middle school in Taiyuan City, Shanxi Province were voluntarily recruited by using random cluster sampling. ActiGraph GT3X+ accelerometer was used to measure 24 hour movement behavior and Inbody J20 body composition analyzer was used to measure body composition. The relationship between each component and obesity indicators was analyzed by compositional multivariate linear regression model. In addition, 30 minutes of one behavior was used to replace another behavior to predict the effect difference of the outcomes.@*Results@#After adjusting for covariates such as height, weight, age, and sex, compared with time spent in sedentary behavior(SB), sleep (SLP) and light physical activity (LPA), time spent on moderate to vigorous physical activity (MVPA) was positively correlated with fat free mass index (FFMI) ( β= 0.40, P ＜0.05), negatively correlated with waist circumference (WC) ( β=-2.50, P ＜0.05) and waist hip ratio (WHR) ( β= -0.04 , P ＜0.05). Compared with SB, SLP and MVPA, time spent on LPA was positively correlated with WHR ( β=0.06, P < 0.05 ). If MVPA of 30 min/d replaces SLP, SB, and LPA respectively, WC and WHR decrease 1.10,1.10,1.34 cm and 0.02, 0.02 ,0.02 respectively, and FFMI increases 0.19,0.19,0.15 kg/m 2 respectively.@*Conclusion@#In 24 h movement behavior, with consistent level of sedentary behavior, sleep or low intensity movement behavior, maintaining a high level of MVPA and replacing sedentary with active activities are crucial for optimal abdominal fat and fat free mass in children and adolescents.

A systematic review of the association between 24 hour movement behavior and obesity in children and adolescents / 中国学校卫生

Objective@#To systematically review the associations of physical activity (PA), sedentary behavior (SB) and sleep with obesity, as well as isotemporal substitution effects among behaviors, determined with compositional data analysis methods, to provide a reference for obesity interventions among children and adolescents.@*Methods@#Studies in the CNKI, Wanfang, PubMed, SPORTDiscus, Web of Science and Medline databases were searched from January 1, 2014 to May 1, 2022. Two experienced reviewers independently completed document screening, data extraction and quality assessment.@*Results@#Sixteen articles were included, with a methodological quality score range of 7-12 points. Moderate to vigorous physical activity (MVPA), sleep and obesity were negatively correlated, and substituting other behaviors with MVPA decreased obesity risk. The substitution time ranged from 1.5 min/day to 60 min/day. Light physical activity(LPA) and SB were positively correlated with obesity.@*Conclusion@#MVPA is the primary focus of obesity interventions in children and adolescents, and extra 60 min of MVPA per week on the existing level of physical activity may be the minimum necessary to decrease the risk of obesity.

Relationship between 24 hour movement behavior and physical fitness among pupils / 中国学校卫生

Objective@#To examine the relationship between 24 hour movement behavior and physical fitness of pupils by using compositional analyses, so as to provide a theoretical basis for physical activity promotion and physical fitness improvement.@*Methods@#By random cluster sampling method, 120 students of grade 4 and 5 from the Second Experimental Primary School of Yingze District of Taiyuan were selected. Physical fitness was evaluated by the indicators of the Protocol of National Physical Training Standard and 20 meter shuttle run. The movement behavior was measured by accelerometer. The relationship between each behavior and physical fitness was analysed by component multiple linear regression, and the effect of replacement of components on physical fitness was discussed.@*Results@#Girls 1minute situps were lower than boys（24.79±7.77，28.21±6.52），and sitting forward flexion was higher than boys[9.00（5.00，14.00），5.20（1.00，9.75）cm]（ t/Z =2.60，-3.15， P ＜0.05）. Boys showed higher light physical activity(LPA), moderate to vigorous physical activity(MVPA) and lower sedentary behavior(SB), while girls showed lower LPA, MVPA and higher SB. MVPA was positively correlated with the performance of 30 second rope skipping and 20 meter shuttle run ( β= 13.19, 7.90, P <0.05). Sleep(SLP), SB, and LPA were not significantly correlated with physical fitness. After re allocating 10 min MVPA to SB and SLP，the performance of 30 second rope skipping and 20 meter shuttle run increased by 2.25，2.28 and 1.28 ,1.34 times，respectively，while significantly decreased after reverse reallocation ( P <0.05). MVPA replaced LPA，the 20 meter shuttle run performance increased 1.46 times，while decreased significantly in reverses ( P <0.05).@*Conclusion@#MVPA is positively correlated with the speed and endurance of pupils. There are gender differences in movement behavior patterns and physical fitness. Children, especially girls, should be encouraged to raise exercise awareness and increase PA, especially MVPA.

A scientific 24 hour movement behavior guideline for the implementation of the "double reduction" policy / 中国学校卫生

Abstract@#As the compositional nature of "constant sum" of physical activity, sedentary behavior and sleep are widely recognized, the methodological and result limitations of previous studies that considered physical activity, sedentary behavior, or sleep as independent influences on physical fitness and health have been highlighted. At present,physical activity guidelines of various countries have shifted from local recommendations based on physical activity amount to global recommendations based on 24 h time frame. From the perspective of time use, the content of daily schedule of children and adolescents also has the attribute of "constant sum" of compositional data, and the reduction of students homework burden and extracurricular discipline training after "double reduction" inevitably means an increase in the time allocated to other activities. From the perspective of time use, the paper focuses on physical fitness and health promotion strategies in the context of "double reduction".

Replacing school and out-of-school sedentary behaviors with physical activity and its associations with adiposity in children and adolescents: a compositional isotemporal substitution analysis

BACKGROUND@#Little is known on how context-specific sedentary behaviors (SB) affect adiposity. This study aimed to investigate compositional associations between context-specific SB and adiposity and estimate the differences in adiposity associated with replacing school and out-of-school SB with physical activity (PA).@*METHODS@#This study included 336 children and adolescents. Time spent in SB and PA was estimated using multi-day 24-hour raw accelerometer data. SB and PA were specified for school and out-of-school times. Fat mass percentage (FM%) and fat mass index (FMI) were used as adiposity indicators. A compositional isotemporal substitution model was used to estimate differences in adiposity associated with one-to-one reallocations of time from context-specific SB to PA.@*RESULTS@#Participants spent approximately two thirds of their school and out-of-school time being sedentary. Relative to the remaining 24-h movement behaviors, significant associations between out-of-school SB and adiposity were found in both boys (β@*CONCLUSIONS@#A reduction of out-of-school SB in favor of light PA should be advocated as an appropriate target for interventions and strategies to prevent childhood obesity.

Associations of distribution of time spent in physical activity and sedentary behavior with obesity / 北京大学学报(医学版)

OBJECTIVE@#To explore associations of distribution of time spent in physical activity (PA) and sedentary behavior (SB) with obesity with taking account that time is finite during the day of adult residents in Wuhai City.@*METHODS@#A cross-sectional study was undertaken in Wuhai City, and we carried out a sampling of local residents aged 18-79 by using multiple stratified cluster sampling method. Data about social demographic characteristics, time spent in PA and SB, diet intake, controlling situation of chronic disease and other covariates were obtained by qualified investigators for face-to-face questionnaire survey. Data about height, weight, and waist circumstance, were obtained by doctors in a secondary hospital or above for body measurements. The statistical method used in our study was known as compositional data analysis, which had been used to process compositional data in many fields. Liner regression analysis with compositional data was used to synthetically analyze the associations of distribution of time spent in PA and SB with obesity,and to investigate the effect of re-allocating time from one behavior to another one whilst the remaining one was kept stable.@*RESULTS@#The investigation revealed the special advantage of compositional data analysis in processing time-use data. The result of liner regression analysis with the compositional data showed that after controlling the potential confounding factors, the associations of distribution of time spent in PA and SB was significantly associated with body mass index (BMI, P<0.001) and the negative natural logarithm of waist to height ratio (-lnWHtR, P<0.001). Among them, in professional population, the proportion of time spent in moderate-to-vigorous physical activity (MVPA) was negatively correlated with -lnWHtR (β=-0.008, P=0.022), while the proportion of time spent in SB was positively correlated with BMI and -lnWHtR (β=0.117, P=0.003; β=0.007, P=0.005). However, in nonprofessional population, the proportion of time spent in MVPA was only negatively correlated with BMI (β=-0.079, P=0.041). Nevertheless, the proportion of time spent in low-intensity physical activity (LIPA) was not significantly associated with BMI and -lnWHtR in both professional and nonprofessional population. In addition, the effects of MVPA replacing another behavior and of MVPA being displaced by another behavior were not symmetrical, and 10 minutes of MVPA replacing LIPA or SB had a greater influence on intervention and prevention of obesity than 10 minutes MVPA being replaced by LIPA or SB.@*CONCLUSION@#The research has resulted in a solution of the associations of the distribution of time spent in PA, SB with health risk. Our results suggest that public health messages should target the health effects of the distribution of time of PA and SB synergistically in developing PA guidelines and health management practice, rather than simply increasing or decreasing the absolute time of PA or SB, so that we can provide scientific suggestions to make people get a profounder healthy effect.

Survey Data on Perceptions of Contraceptive Methods as Compositional Tables / Datos de encuesta sobre percepciones de medidas contraceptivas como tablas composicionales

Abstract This paper studies the relative evaluation of young people and the possible benefits associated with three methods of avoiding sexually transmitted infections/AIDS and/or unwanted pregnancies (condoms, contraceptive pills, morning-after pills). A survey evaluating these three methods, with respect to ten different items, was given to 145 undergraduate students (76% females, 24% males). Results show that, compared to pills, condoms are positively valued as protection against sexually transmitted infections/AIDS, couples are interested in using them to protect their health, and they are appreciated for their lack of side effects. Pills are better valued than condoms with respect to feelings of pleasure for both sexes and not as valued in preventing sexually transmitted infections. Females' assessments are less extreme than male's for five of the six items, but are more pronounced with respect to the assumption that using condoms shows an interest in the couple taking care of their sexual health. The study shows a general preference towards condoms rather than contraceptive pills and postcoital pills, but men are far more likely to choose this option. The conclusions are based on a compositional analysis of two way tables.

Resumen Este trabajo estudia la percepción relativa de los jóvenes de los posibles beneficios asociados a tres métodos para evitar infecciones de transmisión sexual/SIDA y/o embarazos no deseados (condones, píldoras anticonceptivas, píldoras poscoitales o del día después). Al efecto de evaluar estos tres métodos se pasó una encuesta a 145 estudiantes de pregrado (76% mujeres, 24% hombres) con respecto a diez ítems diferentes. Los resultados muestran que, en comparación con las píldoras, los condones se valoran positivamente como protección contra infecciones de transmisión sexual/SIDA, las parejas están interesadas en utilizarlas para proteger su salud, y son apreciados por su falta de efectos secundarios. Las dos píldoras están mejor valoradas que los condones con respecto a los sentimientos de placer para ambos sexos y no tan valoradas en la prevención de infecciones de transmisión sexual. Las evaluaciones de las mujeres son menos extremas que las de los hombres en cinco de los seis ítems, pero son más pronunciadas con respecto a la suposición de que el uso de condones muestra un interés por la pareja cuidando su salud sexual. El estudio muestra una preferencia general hacia los condones en lugar de las píldoras anticonceptivas y las píldoras poscoitales, pero es mucho más probable que los hombres elijan esta opción. Las conclusiones se basan en un análisis composicional de tablas de doble entrada.