Evidence for data missing at random in youth physical activity monitoring research     

P. F. Saint-Maurice  Y. Kim  G. J. Welk 《Journal of sports sciences》2017,35(5):484-490

This study examined whether or not activity monitor data collected as part of a typical 7-day physical activity (PA) measurement protocol can be expected to be missing at random. A total of 315 participants (9–18 years) each wore a SenseWear Armband monitor for 7 consecutive days. Participants were classified as “compliant” (86 boys and 124 girls) if they had recorded accelerometer data during 70% or more of the predefined awake time (7 AM–10 PM) on four different days; and “non-compliant” (44 boys and 51 girls) when not meeting these criteria. Linear mixed models were used to examine differences in energy expenditure (EE) levels by compliance across 10 different time periods. The results indicated that non-compliant girls were older (13.4 ± 2.9 vs. 12.2 ± 2.5) and taller (156.8 ± 10.3 vs. 152.8 ± 11.3) than their same gender compliant peers (P < .05). Comparisons of EE rates at segmented portions of the day revealed no differences between compliant and non-compliant groups (P ≥ .05). Differences in EE ranged from ?0.32 kcal · kg^?1 · h^?1 (before school time) to 0.62 kcal · kg^?1 · h^?1 (physical education class) in boys and ?0.39 kcal · kg^?1 · h^?1 (transportation from school) to 0.37 kcal · kg^?1 · hour^?1 (recess) in girls. The results showed that compliant and non-compliant individuals differed in a few demographic characteristics but exhibited similar activity patterns. This suggests that data were considered to be missing at random, but additional work is needed to confirm this observation in a representative sample of children using other types of activity monitors and protocols.  相似文献   

Tribute to Dr Jacques Rogge: muscle activity and fatigue during hiking in Olympic dinghy sailing     

Jan G. Bourgois  Jasmien Dumortier  Margot Callewaert  Bert Celie  Carlo Capelli  Gisela Sjøgaard 《European Journal of Sport Science》2017,17(5):611-620

‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.

Highlights

• Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.

• Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.

• Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.

• Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.

  相似文献   

Nrf2在有氧运动训练中对小鼠骨骼肌抗氧化能力的作用     

何诗依  张缨 《北京体育大学学报》2017,40(12):50-54

摘要：目的：Nrf2是机体氧化还原平衡的主要调节因子，本研究试图探讨Nrf2在有氧运动训练中对小鼠骨骼肌抗氧化能力的作用。方法：8周龄野生C57BL/6J小鼠和Nrf2敲除小鼠40只，雌雄各半。进一步各为安静组和运动组，每组10只，共4组：分别为野生安静组（WC），野生运动组（WE），敲除安静组（KC）和敲除运动组（KE）。运动组进行4周运动强度为70%VO2max跑速的跑台运动，每周运动6 d，每天运动1 h。运动组最后一次运动后休息48 h脱颈处死，取小鼠后腿骨骼肌。RT-PCR测量Nrf2及Nrf2介导的抗氧化基因mRNA表达量；Western blot法测定骨骼肌Nrf2及抗氧化蛋白含量； GSH试剂盒测量GSH/GSSG比值。结果：1）在安静情况下，KC组和WC组相比，骨骼肌中GSR、NQO1、GCLc、GPX、HO-1和SOD2这6个抗氧化蛋白表达以及GSH/GSSG值没有显著性改变。 2）4周有氧运动训练之后，Nrf2敲除运动组的大部分抗氧化蛋白（CAT, NQO1-1, GCLc, HO-1 and SOD2）和GSH/GSSG值都要显著低于野生运动组。结论：4周70%VO2max强度的有氧运动训练，增加了成年Nrf2敲除和野生鼠骨骼肌抗氧化蛋白表达量和GSH/GSSG比值的差异，而在无训练安静情况下在两种鼠中这些指标的差异不大。说明Nrf2对有氧运动训练中骨骼肌的抗氧化反应起着非常重要的作用。  相似文献   

The effects of school-based physical activity interventions on students' health-related fitness knowledge: A systematic review     

《Educational Research Review》2015

This systematic review includes 34 studies examining the effects of school-based physical activity interventions on students' health-related fitness knowledge. The study design, methodological quality, and effectiveness of interventions on students' health-related fitness knowledge were analysed. The majority of the studies (79.4%) revealed significant positive intervention effects on students' health-related fitness knowledge. Studies examining adolescents were more frequently in a position to influence students' health-related fitness knowledge (87.5%) than studies examining children (75%), and studies with low methodological quality (88.8%) had more frequent positive effects than studies with moderate quality (75%). The effects on students' health-related fitness knowledge were independent of moderator variables such as the intervention content, duration and frequency. Only few studies were able to simultaneously positively influence students' health-related fitness knowledge and students' physical activity and/or fitness levels. These programmes can positively influence students' health-related fitness knowledge, but it remains unclear what the practical significance of these changes is. Further research is needed to clarify the influence of students' health-related fitness knowledge on reflection, understanding, physical activity behaviour, and overall physical literacy levels.  相似文献   

α-淀粉酶活性对不对称重力大小与方向的依赖性     

袁龙飞  刘荣  周影  肖亚婷  何裕建 《中国科学院大学学报》2016,33(3):354-359

手性有左右之分.对于重力,可人为产生左、右手螺旋力.通过光谱学手段,考察不对称重力大小及方向变化对α-淀粉酶活性的影响.结果表明,在1~9 000 g范围内,超重力的增加能够逐渐提高α-淀粉酶活性,并且右手螺旋力比左手螺旋力对于α-淀粉酶活性具有更强的激活作用.考虑到地球天然重力昼夜周期性变化的事实和酶活性对重力大小与方向的依赖性,重力24 h的周期变化可能是昼夜生理节律产生的重要力学原因之一.  相似文献   

父母教养方式对大学生子女体重指数和身体活动行为的影响研究          下载免费PDF全文

尚博睿 《河北体育学院学报》2019,33(4):74-79

运用问卷调查法和数理统计法，对176名大学生及其父母的饮食、身体活动及教养方式进行调查分析。结果显示，子女同父母在体重指数（BMI）上具有显著正相关关系（r=19，P＜05），而在每周平均身体活动量上无显著相关（r=08，P=17）。回归分析表明，三类教养方式对子女BMI均无直接预测作用，然而专制型父母教养方式对父母与子女BMI的相关关系起间接调节作用（P＜01）；在子女身体活动行为方面，溺爱型父母教养方式更有可能导致子女的身体活动不足（P＜01）。研究结果表明，大学生离开家庭环境后，父母教养方式仍然对子女BMI和身体活动行为产生持续影响，父母与子女BMI方面存在相关关系。为今后在青少年肥胖干预及身体活动促进研究中纳入教养方式因素提供了实证依据。  相似文献   

生活方式干预对心血管疾病危险因素的影响——美国HELPS项目成果     

Peter H. Brubaker  罗曦娟  Chelsea Boltj  Shuchang Du 《北京体育大学学报》2017,40(6):48-53

摘要：心血管疾病（CVD）一直是全世界最主要的死因。由于CVD等慢性疾病对健康的威胁越来越大，有必要开展生活方式干预项目以控制这些疾病的危险因素。本研究的目的是评估美国的重要慢病干预项目—HELPS治疗型生活方式改变（TLC）项目对减少CVD危险因素和其他慢性疾病的有效性。方法：140位大学教职工参加为期12周的HELPS TLC项目，干预前后用配对t检验对其体重、BMI、腰围（WC）、6分钟步行距离（6MWD）、空腹血脂和血糖进行测定和比较。结果：干预后6MWD显著增加，总胆固醇（TC）和WC显著下降。对“高危”参与者进一步分析显示：BMI（-1.5±0.5，-3.9%）、TC（- 22.8±4.0，-9.0%）、LDL（- 14.1±4.9，9.3%）和血糖（-6.9±2.2，-6.1%）均显著下降；男性腰围（-4.5±0.8，-10%）显著减小，女性未见显著改变（-1.5±0.5，-4.0%）。此外，体重的变化与TC（r=0.43）、LDL（r=0.35）和血糖（r=0.44）的变化均显著相关。结论：参加12周的生活方式干预项目可以使CVD危险因素减少，特别是在CVD“高危”个体中。HELPS TLC项目的远期效果还待进一步深入研究。  相似文献   

Facilitators and Barriers to Movement Integration in Elementary Classrooms: A Systematic Review     

Robert Dan Michael  Cate A. Egan  Lynda Nilges  Ali Brian  Robert Johnson 《Research quarterly for exercise and sport》2019,90(2):151-162

Purpose: A systematic review was conducted to identify facilitators and barriers to movement integration (MI) in elementary school classrooms. Method: Online databases (Educational Resources Information Center, Google Scholar, PsycINFO, and PubMed) served as data sources for the study. Following the PRISMA guidelines, relevant published research on MI was identified and screened for inclusion in a qualitative synthesis. Content analysis of the included articles (N = 28) was used to identify themes of MI facilitators and barriers. Facilitators and barriers were then categorized using a social-ecological framework. Results: A total of 12 themes of MI facilitators and barriers were identified and categorized into two social-ecological levels: institutional factors (e.g., administrative support, resources) and intrapersonal factors (e.g., teacher confidence, ease of implementation). Conclusion: This review can inform research and practice aimed at supporting the implementation of MI in elementary classrooms.  相似文献   

他山之石：中美高校课外体育活动课程比较研究     

李加奎 《南京体育学院学报(社会科学版)》2016,(4):108-112

我国青年大学生体质健康水平日益下滑，我国大学现行的体育教学模式已不能满足对大学生综合素质培养的需要，构建新的大学体育活动课程体系有利于扭转大学生体质健康水平下滑的不利局面，也为大学生未来的全面发展做铺垫。采用文献资料法和归纳法对美国大学校园娱乐体育的组织管理机制进行梳理和研究，提出我国大学必须完善体育活动课程组织管理体系、加强体育活动课程制度化管理、拓展学校体育活动课程空间、增加大学体育课堂教学内容、纳入体育课程评价体系、推进体育活动课程有偿化服务等建议，以图为我国大学体育活动课程新体系的建设提供思路。  相似文献   

Development and Initial Validation of the Volition in Exercise Questionnaire (VEQ)     

P. Elsborg  J. M. Wikman  G. Nielsen  A. Tolver  A.-M. Elbe 《Measurement in physical education and exercise science》2017,21(2):57-68

The present study describes the development and validation of an instrument to measure volition in the exercise context. Volition describes an individual’s self-regulatory mental processes that are responsible for taking and maintaining a desirable action (e.g., exercising regularly). The scale structure was developed in an exploratory factor analysis which resulted in a reliable structure of the following six factors: Volitional Inhibition—Reasons, Volitional Inhibition—Postponing Training, Volitional Facilitation—Self-Confidence, Volitional Inhibition—Unrelated Thoughts, Volitional Inhibition—Approval From Others, and Volitional Facilitation—Coping with Failure. A sound theoretical explanation for these six factors is based on the Personal System Interaction Theory. This six-factor structure was also confirmed in a new sample in a confirmatory factor analysis, delivering an 18-item questionnaire with strong model fit and good internal consistency. In addition, the Volition in Exercise Questionnaire showed convergent validity because it was able to predict exercise participation. It showed incremental validity by explaining additional variance to the Sport Motivation Scale’s well-established predictors of exercise participation.  相似文献