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.

BODY PRESSURE DISTRIBUTION OF AUTOMOBILE DRIVING HUMAN MACHINE CONTACT INTERFACE

Aiming at the fatigue and comfort issues of human-machine contact interface in automobile driving and based on physiological and anatomical principle, the physiological and biochemical process of muscles and nerves in the formation and development of fatigue is analyzed systematically. The fatigue-causing physiological characteristic indexes are mapped to biomechanical indexes like muscle stress-strain, the compression deformation of blood vessels and nerves etc. from the perspective of formation mechanism. The geometrical model of skeleton and parenchyma is established by applying CT-scanned body data and MRI images. The general rule of comfort body pressure distribution is acquired through the analysis of anatomical structure of buttocks and femoral region. The comprehensive test platform for sitting comfort of 3D adjustable contact interface is constructed. The test of body pressure distribution of human-machine contact interface and its comparison with subjective evaluation indicates that the biomechanical indexes of automobile driving human-machine contact interface and body pressure distribution rule studied can effectively evaluate the fatigue and comfort issues of human-machine contact interface and provide theoretical basis for the optimal design of human-machine contact interface.

Effect of Sand Body Enrichment Under the Restriction of a Tectonic Transfer Zone: A Case Study on the Pinghu Formation in the Kongqueting Region on the Pinghu Slope

Results of long-term explorations in the Kongqueting region,located in an East China Sea depression,suggest that the strong fault activity during the sedimentary period of the Pinghu formation significantly influenced the development of the sedimentary system.However,the aggregation and enrichment of the sand body under a tectonic background has become a problem that requires an immediate solution.Considering research outcomes of previous studies,this study used three-dimensional seismic and logging data to identify Y-or H-type and the en echelon distribution patterns of the fault plane,as well as identify the locations wherein the fault growth index value is greater than 1 in the study region,indicating the tectonic background of the fault transfer zone in the region.Second,the development type of the fault transfer zone was studied,and the sand body enrichment site was identified based on seismic inversion data and the development position of the fault transfer point.This helps clarify the evolution of sedimentary facies of the Pinghu formation combined with the sedimentary environment of the braided-river delta.Finally,after summarizing the coupling relationship between the synsedimentary fault systems and the sand body enrichment patterns,three sand-control models were determined,namely,the flexural-parallel,the en echelon collinear,and the torsional-reformed superimposed transfer zones.The findings of this study lay a foundation for the subsequent search of tectonic lithologic oil and gas reservoirs.

Distribution of shallow water delta sand bodies and the genesis of thick layer sand bodies of the Triassic Yanchang Formation, Longdong Area, Ordos Basin

Based on the cores from 47 wells and logging data of 130 wells,the main types of sand bodies in the shallow water delta of the Chang 8_(2) sub-member in the Triassic Yanchang Formation,Longdong Area,Ordos Basin were comprehensively analyzed,the distribution characteristics of sand bodies more than 20 m thick were identified,and the genetic types of the thick sand bodies were sorted out.In this region,thick-bed sand bodies can be divided into two types according to the shape and position:type 1 is the sand body in wide strip and is distributed between the average high water mark and the average low water mark;type 2 is distributed on both sides of the average low water mark and is in irregular lump shape.Based on the principle of the volume distribution of sediments and the change rule of accommodation space,the genetic models of two types of thick-bed sand bodies in the Chang 8_(2) sub-member are superimposed distributary channel sand bodies in high accommodation space and superimposed composite sand bodies in low accommodation space.

Overweight and obesity in young adults with patellofemoral pain:Impact on functional capacity and strength

Purpose:This study aimed to(a)investigate the proportion of overweight/obesity in a cohort of young adults with patellofemoral pain(PFP)and(b)explore the association of body mass index(BMI),body fat,and lean mass with functional capacity and hip and knee strength in people with PFP.Methods:We included a mixed-sex sample of young adults(18-35 years old)with PFP(n=100).Measurements for BMI,percentage of body fat,and lean mass(assessed by bioelectrical impedance)were obtained.Functional capacity was assessed by the Anterior Knee Pain Scale,plank test,and single-leg hop test.Strength of the knee extensors,knee flexors,and hip abductors was evaluated isometrically using an isokinetic dynamometer.The proportion of overweight/obesity was calculated based on BMI.The association between BMI,body fat,and lean mass and functional capacity and strength was investigated using partial correlations,followed by hierarchical regression analysis,adjusted for covariates(sex,bilateral pain,and current pain level).Results:A total of 38%of our cohort had their BMI categorized as overweight/obese.Higher BMI was associated with poor functional capacity(ΔR^(2)=0.06-0.12,p<0.001)and with knee flexion strength only(ΔR^(2)=0.04,p=0.030).Higher body fat was associated with poor functional capacity(ΔR^(2)=0.05-0.15,p≤0.015)and reduced strength(ΔR^(2)=0.15-0.23,p<0.001).Lower lean mass was associated with poor functional capacity(ΔR^(2)=0.04-0.13,p≤0.032)and reduced strength(ΔR^(2)=0.29-0.31,p<0.001).Conclusion:BMI,body fat,and lean mass should be considered in the assessment and management of young people with PFP because it may be detrimental to function and strength.

Fatty liver is an independent risk factor for gallbladder polyps

BACKGROUND Gallbladder polyps(GBPs)are known to be associated with obesity and metabolic diseases.However,to date,the relationship between GBPs and abnormal body fat distribution,such as fatty liver,visceral obesity,or sarcopenia,has not yet been established.AIM To evaluate whether GBPs are associated with fatty liver,visceral obesity,or sarcopenia.METHODS We retrospectively reviewed the medical records of subjects who underwent various laboratory tests,body composition measurement with a non-invasive body composition analyzer,and abdominal ultrasonography during health checkups.A total of 1405 subjects with GBPs were compared with 2810 age-and sex-matched controls.RESULTS The mean age of the subjects was 46.8±11.7 years,and 63.8%were male.According to multiple logistic regression analysis,the presence of fatty liver[odds ratio(OR)1.413;95%confidence interval(CI)1.218-1.638;P<0.001]was an independent risk factor for GBP,together with low levels of alanine aminotransferase(OR 0.993;95%CI 0.989-0.996;P<0.001).Additionally,fatty liver showed both independent(OR 1.629;95%CI,1.335-1.988;P<0.001)and dosedependent(moderate to severe fatty liver;OR 2.137;95%CI,1.662-2.749;P<0.001)relationship with large GBPs(≥5 mm).The presence of sarcopenia and high visceral fat area were not significantly associated with GBPs.CONCLUSION Fatty liver was found to be closely associated with GBPs irrespective of sarcopenia and visceral obesity.

Sequence of fat partitioning and its relationship with whole body insulin resistance

Background Currently it is unclear whether lipid accumulation occurs in a particular sequence and its relationship with whole body insulin resistance （IR）. This study aimed to answer this question.Methods Male Sprague-Dawley （SD） rats were fed on a normal or a high-fat diet for 20 weeks. Serum triglycerides （TG）, serum free fatty acids （FFA）, fasting plasma glucose （FPG）, and liver and skeletal muscle TG were measured. The glucose infusion rate （GIR） and mRNA levels of acetyl-CoA carboxylase （ACC） and carnitine palmitoyltransferase-1 （CPT-1） in the liver and skeletal muscle were determined at different stages.Results Compared with rats fed on the normal diet, serum FFA was not significantly increased in rats fed on the high-fat diet until 20 weeks. In contrast, liver TG was significantly increased by the high-fat diet by four weeks （20-fold; P ＜0.01）,and remained elevated until the end of the study. However, skeletal muscle TG was not significantly increased by the high-fat diet until 20 weeks （10.6-fold; P＜0.01）, and neither was the FPG. The GIR was significantly reduced （1.6-fold; P ＜0.01） by the high-fat diet after 8 weeks. The mRNA levels of ACC gradually increased over time and CPT-1 decreased over time, in both the liver and skeletal muscle in rats fed the high-fat diet.Conclusions Lipid accumulation in the liver occurs earlier than lipid accumulation in the skeletal muscle. Fatty liver may be one of the early markers of whole body IR. Changes in the gene expression levels of ACC and CPT-1 may have important roles in the process of IR development.