Association of daily sitting time and leisure-time physical activity with body fat among U.S.adults

Background:Prolonged sitting and reduced physical activity lead to low energy expenditures.However,little is known about the joint impact of daily sitting time and physical activity on body fat distribution.We investigated the independent and joint associations of daily sitting time and physical activity with body fat among adults.Methods:This was a cross-sectional analysis of U.S.nationally representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or older.Daily sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity Questionnaire.Body fat(total and trunk fat percentage)was determined via dual X-ray absorptiometry.Results:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past week.After fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both sexes.When stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently active.In the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/day.Conclusion:Prolonged daily sitting time was associated with increased body fat among U.S.adults.The higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

Effects of combined physical and cognitive training on executive function of adolescent shooting athletes:A functional near-infrared spectroscopy study

Individual executive function improvement through physical and cognitive training is a research hotspot in physical education and cognitive science.However,few studies have evaluated whether combined physical and cognitive training(CPCT)has greater benefits for executive function performance and cerebral oxygenation in adolescent athletes than cognitive training alone.This study randomly assigned 33 adolescent shooting athletes to a CPCT(n=17)or computerized cognitive training(CCT,n=16)group and compared their executive function after six weeks of training.All subjects were assessed using the 2-back,task-switching,and Stroop tests before and after training.The prefrontal cortex oxygenated hemoglobin(Oxy-Hb)activation level was monitored while executing the three tasks using functional near-infrared spectroscopy.Our results showed that the CPCT and CCT groups similarly improved their updating function as indicated by the 2-back task accuracy.The CPCT group significantly improved the switching function in the task-switching test accuracy,while the CCT group did not.However,both groups did not improve in behavioral performance as indicated by the inhibition function in the Stroop task.Cerebral oxygenation,indicated by the oxy-Hb activation level in the frontal pole area of the prefrontal lobe,significantly improved in the CPCT group during the three cognitive tasks,whereas the CCT group showed no change.These findings indicated that CPCT endowed greater advantages in task-switching in the behavioral performance of the executive function than CCT.Moreover,CPCT was superior to CCT in increasing task-efficient cerebral oxygenation during the activation of the prefrontal cortex in adolescent shooting athletes.

Effects of a 12-Week Recreational Soccer Program on Resting Metabolic Rate Among Adolescents with Obesity

Objectives The purpose of this study was to investigate the chronic effects of a 12-week recreational soccer program(RSP)on resting metabolic rate(RMR)in adolescents with obesity.Methods Eighteen adolescents with obesity were assigned to RSP[n=10,age=13.8±1.5 years,body mass index(BMI)=30.7±5 kg/m^(2)]and control(n=8,age=14.9±1.4 years,BMI=32.5±4.1 kg/m^(2))groups.Participants underwent anthropometric,body composition,cardiorespiratory fitness and RMR assessments at baseline and post-intervention.The 12-week RSP consisted of small-sided games with 60-min performed 3 times per week.Results Post-intervention,between-group differences due to RSP emerged for body mass(Δ:−15.1 kg,P=0.043),BMI(Δ:−4.7 kg,P=0.05),waist and hip circumferences(Δ:−14.6 and−16.6 cm,P=0.015 and P=0.017,respectively),fat mass(Δ:−8.7 kg,P=0.049)and VO2max(Δ:5.5 mL/kg/min,P=0.013).No significant differences were detected for the absolute and adjusted RMR for fat mass and fat-free mass at baseline and after 12 weeks for both RSP and control groups,although a marked downward trend of 27.6%for adjusted RMR was observed post-control(1915 vs.1386 kcal/day;Δ:−529 kcal/day).Conclusion A 12-week RSP was effective for improving anthropometric,body composition and cardiorespiratory fitness health markers in adolescents with obesity,but not for RMR.