The mirror’s curse: Weight perceptions mediate the link between physical activity and life satisfaction among 727,865 teens in 44 countries

Purpose:The present study aimed to examine the link between physical activity(PA)and life satisfaction in a large international study of adolescents.We also aimed to test whether overweight and underweight perceptions act as mediators and whether age and sex acted as moderators.Methods:For this purpose,we analyzed data from the Health Behavior in School-aged Children study,which comprises 727,865 observations from 44 nations at 4 measurement occasions.Results:Multilevel analyses revealed a positive link between PA and life satisfaction.In addition,underweight and overweight perceptions mediated the effect of PA on life satisfaction.We further found that age and sex acted as moderators.In older adolescents,stronger effects were found in the links between PA and life satisfaction,PA and overweight perception,and both weight perceptions and life satisfaction.In addition,in female adolescents,the link between overweight perception and life satisfaction was stronger.Conversely,the links between PA and both weight perceptions were stronger for boys.Conclusion:The results suggest that weight perception explains part of the relationship between PA and life satisfaction in adolescents and that these effects vary as a function of age and sex.     

中学生体育学习动机与坚持性和努力程度的关系研究——成就目标理论多元观视角

The purpose of this study was to examine students' achievement goals,social goals,and their relationships with their self-reported persistence and effort in secondary school physical activity settings. The results from regression analyses revealed that students' social-responsibility goals ,mastery-ap-proach goals,social-relationship goals,and performance-avoidance goals had a significant positive effect toward their persistence and effort in physical activity settings,while students' mastery-avoidance goals had a significant negative effect toward their persistence and effort. There were significantly interactive effects between social goals and achievement goals. Additionally,students' social-responsibility goals and social-relationship goals had both direct and indirect effects toward their persistence and effort. Finally,mastery-approach and mastery-avoidance goals not only had direct effects toward their persistence and effort,but had important mediated effects between students' social goals and their persistence and effort in physical activity settings.     

Chronic ankle instability is associated with proprioception deficits: A systematic review and meta-analysis

Background:Acute ankle injury causes damage to joint mechanoreceptors and deafferentation and contributes to proprioception deficits in patients with chronic ankle instability(CAI).We aimed to explore whether deficits of proprioception,including kinesthesia and joint position sense(JPS),exist in patients with CAI when compared with the uninjured contralateral side and healthy people.We hypothesized that proprioception deficits did exist in patients with CAI and that the deficits varied by test methodologies.Methods:The study was a systematic review and meta-analysis.We identified studies that compared kinesthesia or JPS in patients with CAI with the uninjured contralateral side or with healthy controls.Meta-analyses were conducted for the studies with similar test procedures,and narrative syntheses were undertaken for the rest.Results:A total of 7731 studies were identified,of which 30 were included for review.A total of 21 studies were eligible for meta-analysis.Compared with the contralateral side,patients with CAI had ankle kinesthesia deficits in inversion and plantarflexion,with a standardized mean difference(SMD)of 0.41 and 0.92,respectively,and active and passive JPS deficits in inversion(SMD=0.92 and 0.72,respectively).Compared with healthy people,patients with CAI had ankle kinesthesia deficits in inversion and eversion(SMD=0.64 and 0.76,respectively),and active JPS deficits in inversion and eversion(SMD=1.00 and 4.82,respectively).Proprioception deficits in the knee and shoulder of patients with CAI were not statistically significant.Conclusion:Proprioception,including both kinesthesia and JPS,of the injured ankle of patients with CAI was impaired,compared with the uninjured contralateral limbs and healthy people.Proprioception varied depending on different movement directions and test methodologies.The use of more detailed measurements of proprioception and interventions for restoring the deficits are recommended in the clinical management of CAI.     

Journal of Sport and Health Science Guide for Authors

Please visit https://www.journals.elsevier.com/journal-of-sport-and-health-science for the detailed version of Guide for Authors.Aims The Journal of Sport and Health Science (JSHS) is a peer-reviewed,international,multidisciplinary journal dedicated to the advancement of sport,exercise,physical activity,and health sciences.JSHS publishes original and impactful research,topical reviews,editorials,opinion,and commentary papers relating physical and mental health,injury and disease prevention,traditional Chinese exercise,and human performance.Through a distinguished,carefully selected international editorial board,JSHS has adopted the highest academic standards,impeccable integrity,and an efficient publication platform.     

数据库

1. Beijing will host a series of high-profile international competitions next year. The Chinese capital will stage the opening and closing ceremonies and the final of the Asian Cup soccer finals and an NBA game between the Houston Rockets and the Sacramento Kings. Beijing is also preparing for the 2005 Sudirman Cup badminton championship and bidding for the 2005 World Taekwondo Championships and 2006 World Youth Athletics Championships.     

Beijing Seeks Better Weather Forecasts

Chinese Vice-Premier Zeng Peiyan has urged Beijing and other cities to improve their urban planning and increase their disaster prevention and control capability.The call came as downpours caused casualties and traffic jams in some major cities in July.The vice-premier said all localities and departments should increase their investment in urban infrastructure concerning water supply and drainage, energy and telecommunications, and     

基于 OpenSim 技术的跨栏跟腱仿真分析

Using the biomechanical simulation method based on OpenSim software which combines motion capture and muscle-bone model techniques ,this study built a lower extremity model. The dynamic optimization method was adopted to calculate the muscle force and biomechanical analysis was also used on Achilles tendon（AT）loading and muscle-tendon unit（MTU）strain. The results indicated that soleus MTU and Gastrocnemius MTU were tensile and had deformation during hurdling and running. Soleus MTU deformation difference were 0.031 mm and 0.016 mm ;Gastrocnemius MTU deformation difference were 0.031 mm and 0.031 mm;Achilles tendon loading in hurdling and running were （ 4 066.91±322.56）N and （3 361.76±194.01 ）N. This study can provide a scientific basis for the prevention of Achilles tendon injury in hurdling and further the study on Achilles tendon injury mechanism.     

Injury and illness in short-course triathletes:A systematic review

Background:Determining the incidence and prevalence of injury and illness in short-course triathletes would improve understanding of their etiologies and therefore assist in the development and implementation of prevention strategies.This study synthesizes the existing evidence on the incidence and prevalence of injury and illness and summarizes reported injury or illness etiology and risk factors affecting short-course triathletes.Methods:This review followed the Preferred Reporting Items for S...     

Journal of Sport and Health Science Guide for Authors

Aims The Journal of Sport and Health Science(JSHS)is a peer-reviewed,international,multidisciplinary journal dedicated to the advancement of sport,exercise,physical activity,and health sciences.JSHS publishes original and impactful research,topical reviews,editorials,opinion,and commentary papers relating physical and mental health,injury and disease prevention,traditional Chinese exercise,and human performance.Through a distinguished,carefully selected international editorial board,JSHS has adopted the highest academic standards,impeccable integrity,and an efficient publication platform.     

Social correlates of sedentary behavior in young people:The UP&DOWN study

Purpose:The aim of the present study was to analyze the associations of youths' sedentary behavior(SB) with parents' and siblings' SB and physical activity(PA),as well as the associations of youths' coparticipation with parents,siblings,and friends in PA and SB with youths' SB.Methods:The sample consisted of 1543 youths(12.02±2.51 years;788 boys) enrolled in the baseline cohort of the UP&DOWN study.SB was assessed by accelerometry and questionnaire.Participants reported the time spent by their parents and siblings watching television,playing videogames,surfing the Internet,sitting/resting,and doing PA.Further,participants reported coparticipation with parents,siblings,and friends in these activities.Linear mixed models,including school and city as random effects,were performed.Results:Parents' television time was positively associated with youths' screen-based SB.Coparticipation with friends in playing videogames(in boys) and in surfing the Internet(in girls) showed a positive association with screen-based SB and a negative association with educational-based SB.Moreover,coparticipation with siblings and friends in PA was inversely associated with accelerometer-based SB in boys and girls.Conclusion:Our results emphasize the important role of social modeling in the development of sedentary lifestyles in youths.Interventions aimed at reducing health risk behaviors in youths could be more effective if they are oriented from a social perspective that involves their families and networks of their closest friends.     

Author biographies of EIC's choice

Dr.Eduardo Iglesias-Gutiérrez is a faculty member of the Department of Functional Biology,at the University of Oviedo,Spain.He holds a Ph.D.on Molecular and Functional Biology and a M.Sc.in Food Biotechnology.His research interests focus on the molecular response to exercise,with particular emphasis on nutrition and epigenetics.These research lines aim to translate basic scientific information into applied strategies to promote a healthy lifestyle and optimize performance.He is an author of more than 30 peer-reviewed publications,representing research that has received funding from different national agencies and other sources.Dr.Iglesias-Gutiérrez is an Associate Editor of Nutrients and Pharma Nutrition.     

Correlation network analysis shows divergent effects of a long-term,high-fat diet and exercise on early stage osteoarthritis phenotypes in mice

Background:Obesity increases knee osteoarthritis(OA) risk through metabolic,inflammatory,and biomechanical factors,but how these systemic and local mediators interact to drive OA pathology is not well understood.We tested the effect of voluntary running exercise after chronic diet-induced obesity on knee OA-related cartilage and bone pathology in mice.We then used a correlation-based network analysis to identify systemic and local factors associated with early-stage knee OA phenotypes among the different diet and exercise groups.Methods:Male C57 BL/6 J mice were fed a defined control(10% kcal fat) or high fat(HF)(60% kcal fat) diet from 6 to 37 weeks of age.At 25 weeks,one-half of the mice from each diet group were housed in cages with running wheels for the remainder of the study.Histology,micro computed tomography,and magnetic resonance imaging were used to evaluate changes in joint tissue structure and OA pathology.These local variables were then compared to systemic metabolic(body mass,body fat,and glucose tolerance),inflammatory(serum adipokines and inflammatory mediators),and functional(mechanical tactile sensitivity and grip strength) outcomes using a correlation-based network analysis.Diet and exercise effects were evaluated by two-way analysis of variance.Results:An HF diet increased the infrapatellar fat pad size and posterior joint osteophytes,and wheel running primarily altered the subchondral cortical and trabecular bone.Neither HF diet nor exercise altered average knee cartilage OA scores compared to control groups.However,the coefficient of variation was≥25% for many outcomes,and some mice in both diet groups developed moderate OA(>33% maximum score).This supported using correlation-based network analyses to identify systemic and local factors associated with early-stage knee OA phenotypes.In wheel-running cohorts,an HF diet reduced the network size compared to the control diet group despite similar running distances,suggesting that diet-induced obesity dampens the effects of exercise on systemic and local OA-related factors.Each of the 4 diet and activity groups showed mostly unique networks of local and systemic factors correlated with early-stage knee OA.Conclusion:Despite minimal group-level effects of chronic diet-induced obesity and voluntary wheel running on knee OA pathology under the current test durations,diet and exercise substantially altered the relationships among systemic and local variables associated with early-stage knee OA.These results suggest that distinct pre-OA phenotypes may exist prior to the development of disease.     

Overtraining/Overreaching:Leptin and Ghrelin in Male Recruits

Background In many sports,athletes with low body weight and/or low body fat content have a distinct advantage over their opponents.Such an advantage can easily turn into a noticeable disadvantage because low body weight and 'leanness' may also be associated with health problems.Anorexia Athletica(AA) is associated with leanness and thinness in female and male sports athletes despite the fact that these athletes are often very successful.High-competitive athletes often restrict their caloric intake and/or increase their energy expenditure to maintain a low body mass and/or a low amount of body fat.Several metabolic and endocrine disturbances are often the result of prolonged energy restriction.These disturbances can be detected by alterations in the hormonal profile(low levels of leptin,increased levels of ghrelin) and in changes in body composition.     

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 ...     

Ancient City Athens

Athens is an ancient city and it has anenormous amount to offer both touristsand business travelers alike. The city hasmild winters and hot summers and isworth a visit whatever time of the year. Plaka is the old town of Athens and hasbeen populated for over 5,000 years.Situated on the north and east slopes ofthe Acropolis, it is rich with historic sites,su ch a s a ncie nt monu men ts a ndchurches, and Plaka in Athens is wellworth exploring. Within Athens there areeight large hills, includi…     

Knee biomechanics of patients with total knee replacement during downhill walking on different slopes

Purpose:The purpose of this study was to compare knee biomechanics of the replaced limb to the non-replaced limb of total knee replacement(TKR)patients and healthy controls during walking on level ground and on decline surfaces of 5°,10°,and 15°.Methods:Twenty-five TKR patients and 10 healthy controls performed 5 walking trials on different decline slopes on a force platform and an instrumented ramp system.Two analyses of variance,2×2(limb×group)and 2×4(limb×decline slope),were used to examine selected biomechanics variables.Results:The replaced limb of TKR patients had lower peak loading-response and push-off knee extension moment than the non-replaced and the matched limb of healthy controls.No differences were found in loading-response and push-off knee internal abduction moments among replaced,non-replaced,and matched limb of healthy controls.The knee flexion range of motion,peak loading-response vertical ground reaction force,and peak knee extension moment increased across all slope comparisons between 0°and 15°in both the replaced and non-replaced limb of TKR patients.Conclusion:Downhill walking may not be appropriate to include in early stage rehabilitation exercise protocols for TKR patients.     

At,In and On:Expressions of Time and Place

At,in and on are the three common preposions They are all used to talk about time and position in space.The differences between them are rather complicated.and it is not always to know which of the three is correct.In order to provide refendnece for studying and teaching,I‘vesummed up the usage of the threeas follows.     

承前启后的体育盛会

The Ninth Game of the People's Republic of China was held in Guangzhou from November 11th to 25th of 2001. 12314 athletes of 45 teams from all over the country attended preliminary contests, and 8608 athletes attended final games. Our athletes have struggled with their full strengths and created a bunch of excellent results at this game. 24 persons and 35 person-times have exceeded seven world records in 30 items and 345 sub-items, and six persons and one team have     

纵跳落地动作地面反作用力计算机仿真方法的研究

It is significant to investigate the landing load suffered by high-level athletes for evaluating the training effect and prevention of injury. Simulation can get the ground reaction force （GRF）that can't be gotten by force platforms,but the accuracy of data needs to be confirmed. The study investigated the similarity and characteristic values of landing force curves got by simulation and force platforms to verify the accuracy and reliability of Lifemod simulation. Results showed that the CMCs of GRF curves gotten by simulation and force platforms were all about 0.90 representing the high correlation. The difference value of maximum GRF was 1.4% of the maximum GRF got by force platforms,and the time difference of getting the maximum GRF was 0.002s.Conclusion：Accurate data matching the real value could be got by simulation. It is feasible and accurate to get the GRF of national level athletes in the training and match.     

Using compositional data analysis to explore accumulation of sedentary behavior,physical activity and youth health

Purpose:The study aimed to describe youth time-use compositions,focusing on time spent in shorter and longer bouts of sedentary behavior and physical activity(PA),and to examine associations of these time-use compositions with cardiometabolic biomarkers.Methods:Accelerometer and cardiometabolic biomarker data from 2 Australian studies involving youths 7-13 years old were pooled(complete cases with accelerometry and adiposity marker data,n=782).A 9-component time-use composition was formed using compositional data analysis:time in shorter and longer bouts of sedentary behavior;time in shorter and longer bouts of light-,moderate-,or vigorous-intensity PA;and"other time"(i.e.,non-wear/sleep).Shorter and longer bouts of sedentary time were defined as<5 min and>5 min,respectively.Shorter bouts of light-,moderate-,and vigorous-intensity PA were defined as<1 min;longer bouts were defined as≥1 min.Regression models examined associations between overall time-use composition and cardiometabolic biomarkers.Then,associations were derived between ratios of longer activity patterns relative to shorter activity patterns,and of each intensity level relative to the other intensity levels and"other time",and cardiometabolic biomarkers.Results:Confounder-adjusted models showed that the overall time-use composition was associated with adiposity,blood pressure,lipids,and the summary score.Specifically,more time in longer bouts of light-intensity PA relative to shorter bouts of light-intensity PA was significantly associated with greater body mass index z-score(zBMI)(β=1.79;SE=0.68)and waist circumference(β=18.35,SE=4.78).When each activity intensity was considered relative to all higher intensities and"other time",more time in light-and vigorous-intensity PA,and less time in sedentary behavior and moderate-intensity PA,were associated with lower waist circumference.Conclusion:Accumulating PA,particularly light-intensity PA,in frequent short bursts may be more beneficial for limiting adiposity compared to accumulating the same amount of PA at these intensities in longer bouts.