Habitual physical activity levels and sedentary time of children in different childcare arrangements from a nationally representative sample of Canadian preschoolers

BackgroundChildren spend substantial time in childcare, and the reasons parents choose a particular childcare type may differ by family. However, little is known about how childcare type influences habitual (full day) activity levels among children. Therefore, exploring patterns between childcare type and habitual physical activity (PA) (i.e., light, moderate-to-vigorous PA (MVPA), and total PA) and sedentary time (ST) in young Canadian children is needed.MethodsA nationally representative sample of preschoolers from Cycles 3 and 4 of the Canadian Health Measures Survey was used in this cross-sectional study. Childcare type (e.g., center-based childcare, home-based childcare, home with parent, kindergarten) was reported by parents. Preschoolers wore an Actical accelerometer for 7 days. Device and population-spcific cut-points were applied to delineate PA intensities and ST. Population means and sample totals were calculated to examine average daily and hourly rates of activity.ResultsPreschoolers’ rates of MVPA and total PA from the 4 childcare arrangements ranged from 65.99 min/day to 74.62 min/day (5.48–6.18 min/h) and 274.20 min/day to 281.66 min/day 22.69–23.21 min/h), respectively, while ST ranged from 443.13 min/day to 460.57 min/day (36.80–37.31 min/h). No significant differences were observed in daily or hourly rates of activity.ConclusionThis study provides a snapshot of the levels of PA and ST among preschoolers in various childcare settings at a national level, with no differences observed in habitual activity levels based on childcare enrollment. Additional research is needed to clarify the relationship between young children's PA and childcare type, with consideration given to the quality of the childcare settings.     

Low fundamental movement skill proficiency is associated with high BMI and body fatness in girls but not boys aged 6–11 years old

This study examined differences in children’s body mass index (BMI) and body fatness (BF%) as a function of gender and fundamental movement skill (FMS) proficiency. Following ethics approval and parental consent, 248, 6–11 year-old children (112 boys, 136 girls) underwent assessment of 7 FMS: sprint run, side gallop, hop, kick, catch, throw and vertical jump. FMS tertiles (“high”, “medium” or “low” FMS) were created based on the summed components of the FMS. Skinfold measures were used to calculate BF%. Physical activity (PA) was assessed using pedometry and maturation predicted using anthropometry. Data were analysed using a 2 (Gender) × 3 (FMS tertile) ways analysis of covariance (ANCOVA), controlling for age, maturation and PA. Age (P = .001) and maturation (P = .006) were associated with BMI. Girls classified as high FMS proficiency had significantly lower BMI compared to girls with low and medium FMS proficiency. Age (P = .0001) and maturation (P = .007) were associated with BF%. BF% was also higher for girls with low FMS compared to those with medium and high FMS. BF% and BMI were not different across FMS tertile in boys. Such findings suggest focusing on FMS may be especially important for healthy weight, particularly in girls.     

Effects of different physical education programmes on children’s skill- and health-related outcomes: a pilot randomised controlled trial

Aim of this study was to evaluate the effectiveness of two different 5-month physical education (PE) interventions conducted by a specialist PE teacher on primary school children’s skill- and health-related outcomes. About 230 children were randomly assigned to one of three intervention groups: experimental_1 group, experimental_2 group or control group (school curriculum given by the generalist teacher). Pre- and post-intervention tests assessed pupils’ fitness (pacer, curl-up, push-up, trunk lift, sit and reach tests) and gross motor coordination (shifting platforms, balance beam, jumping laterally, hopping on one leg over an obstacle tests). Both experimental groups significantly improved some fitness and coordinative tests after the intervention period when compared with control group. However, no differential changes on coordinative development were observed between the 2 experimental groups. Results of this study demonstrated that children benefitted from a well-structured PE intervention conducted and supervised by a specialist PE teacher improving their motor skills and fitness.     

运动技能教学中学生学习策略的培养

学习策略是学生进行自我学习的一种高级方式,学习策略的形成有其内在的规律性。就学习策略的基本特征以及在运动技术教学中如何培养学生运动技术的学习策略提出了一些基本的建议。     

Slowed driving-reaction time following concussion-symptom resolution

Background: Concussed patients have impaired reaction time (RT) and cognition following injury that may linger and impair driving performance. Limited research has used direct methods to assess driving-RT post-concussion. Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT''s relationship with traditional computerized neurocognitive testing (CNT) domains.MethodsWe employed a cross-sectional study among 14 concussed (15.9 ± 9.8 days post-concussion, mean ± SD) individuals and 14 healthy controls matched for age, sex, and driving experience. Participants completed a driving simulator and CNT (CNS Vital Signs) assessment within 48 h of symptom resolution. A driving-RT composite (ms) was derived from 3 simulated driving scenarios: stoplight (green to yellow), evasion (avoiding approaching vehicle), and pedestrian (person running in front of vehicle). The CNT domains included verbal and visual memory; CNT-RT (simple-, complex-, Stroop-RT individually); simple and complex attention; motor, psychomotor, and processing speed; executive function; and cognitive flexibility. Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups, Pearson correlations (r) examined driving RT and CNT domain relationships among cohorts separately, and p values were controlled for false discovery rate via Benjamini-Hochberg procedures (α = 0.05).ResultsConcussed participants demonstrated slower driving-RT composite scores than controls (mean difference = 292.86 ms; 95% confidence interval (95%CI): 70.18–515.54; p = 0.023; d = 0.992). Evasion-RT (p = 0.054; d = 0.806), pedestrian-RT (p = 0.258; d = 0.312), and stoplight-RT (p = 0.292; d = 0.585) outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits. Among concussed individuals, driving-RT outcomes did not significantly correlate with CNT domains (r-range: –0.51 to 0.55; p > 0.05). No correlations existed between driving-RT outcomes and CNT domains among control participants either (r-range: –0.52 to 0.72; p > 0.05).ConclusionSlowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns. Driving-RT and CNT-RT measures correlated moderately but not statistically, which indicates that CNT-RT is not an optimal surrogate for driving RT.     

Multidimensional joint coupling: a case study visualisation approach to movement coordination and variability

Abstract

A case study visualisation approach to examining the coordination and variability of multiple interacting segments is presented using a whole-body gymnastic skill as the task example. One elite male gymnast performed 10 trials of 10 longswings whilst three-dimensional locations of joint centres were tracked using a motion analysis system. Segment angles were used to define coupling between the arms and trunk, trunk and thighs and thighs and shanks. Rectified continuous relative phase profiles for each interacting couple for 80 longswings were produced. Graphical representations of coordination couplings are presented that include the traditional single coupling, followed by the relational dynamics of two couplings and finally three couplings simultaneously plotted. This method highlights the power of visualisation of movement dynamics and identifies properties of the global interacting segmental couplings that a more formal analysis may not reveal. Visualisation precedes and informs the appropriate qualitative and quantitative analysis of the dynamics.     

Influence of Adiposity and Maturation on the Motor Performance of Girls Aged 8 to 16 Years

ABSTRACT

Excess adipose tissue may impact the motor performance of youth. Therefore, the current study examined (a) if adiposityinfluenced performance in the jump and reach and 30-yard dash and (b) if maturation predicted motor performance. Participants (N = 267) included girls aged 8 to 16 years. Latent growth curves were used to assess changes in motor performance. Sum of skinfolds predicted jump and reach performance from age 8.5 to 10.5 years, 11.5–12.0 years, 13.0 years, and from age 14 to 14.5 years (b = ?0.013 to 0.051, p < 0.05). Sum of skinfolds predicted 30-yard dash performance from age 8.5 to 14.0 years and at age 15.5 years (b = 0.003 to 0.005, p < 0.05). Maturation did not predict performance. Future research should examine determinants that explain the link between adiposity and motor performance.     

基于运动技能分类的运动心理准备

运动技能对运动员赛场发挥及优异表现具有决定性作用,在运动训练和体育教学实践中也是核心要素.虽然长期以来对运动技能有多种不同的分类方式,但所有运动技能大体上可以分为开放式和封闭式运动技能.基于此,本文主要论述三个问题:(1)解释开放式和封闭式运动技能各自的特征;(2)论述开放式和封闭式运动技能的训练要点;(3)根据两种不同技能分类,介绍心理准备的方法,使运动员在比赛中取得最佳成绩.开放式运动技能要求运动员必须根据外界刺激做出快速决断,快速反应时间至关重要.运动员的动作应集中于结果而不是过程,因此,运动员可以自由选择任何形式的技能来完成特定任务.另外,开放式运动技能还应有很大的创造性和准确性.与此相反,封闭式运动技能允许运动员有相对充足的决策或判断时间,竞争环境稳定、可预测,且规则和评判运动技能的标准也是预定的.更为重要的是,封闭式运动技能强调技能的完美表现.开放式和封闭式运动技能的执行是通过两个不同的神经肌肉系统:闭环神经控制系统和开环神经控制系统.依据动作技能的不同特征和控制系统,在训练中应具有针对性.开放式运动技能应培养运动员快速决策能力,使运动员在执行运动技能时采取尽可能快的行动,同时,还应对技能的准确性进行重点训练.在科学的训练过程中,应使运动员拥有最大限度的技能贮备以应对竞赛中的不同状况.需要指出的是,开放式运动技能的训练或学习应强调结果而不是过程.封闭式运动技能的训练应强调在规则和技能标准的范畴内最大限度保证动作技能完成的准确性,在此基础之上进行重复训练,追求技能的完美表现.训练中还应重点对运动员的注意力进行强化.开放式运动技能的心理准备要点包括认知竞赛动态性的本质、了解敌我双方的优劣势、与队友在比赛中有效沟通、实施有效的激励策略、建立运动员自信.封闭式运动技能的心理准备要点包括动作执行之前进行充分的决策、认知运动技能的生物力学特征、根据运动技能的难易准确有效控制发力程度、运动技能表现应确保具有高度的一致性和准确性、充分重视运动技能之间的衔接和转换、高度集中注意力进而有效排除运动技能执行过程中的干扰因素.     

微型飞行器驱动装置特性试验研究

本文以南航研究成功的某型号微型飞行器为背景,用理论计算和试验验证的方法,研究了利用传统飞行器飞行力学方程推算微型飞行器驱动装置参数的可行性,同时研究了静态条件下电动机和螺旋桨的不同匹配对整个动力装置的影响。     

第斯多惠的主张与运动训练中的和谐教育

长期以来,我们的运动训练只注重成绩的提高,缺乏对运动员的人性教育和精神的培养,致使出现了一些个人的和社会的问题。"和谐社会"理论引导我们要培养"和谐"的人,要重视对运动员进行和谐教育,促进全面发展。按照第斯多惠的和谐教育主张,我们的训练中要激发运动员的主动性、遵循运动员的自然发展规律、注重运动员的自我完善、全面发展身体和精神。这样才能培养出"和谐社会"需要的人才,才能保证运动员与社会的"和谐"。