The application of inertial measurement units and functional principal component analysis to evaluate movement in the forward 3½ pike somersault springboard dive     

Cherie Walker  John Warmenhoven  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(2):146-162

Based on technological and analytical advances, the capability to more accurately and finitely examine biomechanical and skill characteristics of movement has improved. The purpose of this study was to use Inertial Measurement Units (IMUs) and Functional Principal Components Analysis (fPCA) to examine the role of movement variability (assessed via angular velocity), on 2 divers (1 international level; 1 national) performing the forward 3½ pike somersault dive. Analysis of angular velocity curves during ive-flight identified 5 fPCs, accounting for 96.5% of movement variability. The national diver’s scatter plots and standard deviation of fPC scores illustrated larger magnitudes of angular velocity variability across dive flight. For fPC1 and fPC3, magnitudes of SD variability were 282.6 and 201.5, respectively. The international diver illustrated more consistent angular velocity profiles, with clustering of fPCs scores (e.g., fPC1 & 3 = SD’s of 75.2 & 68.0). To account for lower variability in the international diver, the ability to better coordinate movement sequences and functionally utilise feedback in response to initiation of the somersault position is highlighted. Overall, findings highlight how both IMUs and fPCA can more holistically and finitely examine the biomechanical and skill characteristics of movement sequences with the capability to inform athlete development.  相似文献   

基于用户兴趣度量的知识发现服务精准推荐     

丁梦晓  毕强  许鹏程  李洁  牟冬梅 《图书情报工作》2019,63(3):21-29

[目的/意义]针对当前知识发现服务中存在的个性化程度不高和推荐效果不佳等问题，提出一种基于用户兴趣度量和内容分析的推荐算法。[方法/过程]文章通过特征词分布、LDA主题分布、引文结构网络三个维度构建学术资源模型，并通过对用户行为的度量，计算用户对其浏览学术资源的兴趣度，结合学术资源模型构建用户兴趣模型。将用户兴趣模型与学术资源模型匹配，计算其相似度，得到用户对每条学术资源的兴趣值，最后将兴趣值最高的TOP-N学术资源推荐给用户。[结果/结论]通过实验检验算法的有效性和推荐准确率，结果显示，本文从实时动态度量兴趣的角度，提出的推荐算法能较好地预测用户兴趣，推荐效果显著，为实现发现服务精准推荐提供思路。  相似文献   

The influence of water depth on kinematic and spatiotemporal gait parameters during aquatic treadmill walking     

Taeyou Jung  Yumi Kim  Hyosok Lim  Konstantinos Vrongistinos 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):297-307

The purpose of this study was to investigate kinematic and spatiotemporal variables of aquatic treadmill walking at three different water depths. A total of 15 healthy individuals completed three two-minute walking trials at three different water depths. The aquatic treadmill walking was conducted at waist-depth, chest-depth and neck-depth, while a customised 3-D underwater motion analysis system captured their walking. Each participant’s self-selected walking speed at the waist level was used as a reference speed, which was applied to the remaining two test conditions. A repeated measures ANOVA showed statistically significant differences among the three walking conditions in stride length, cadence, peak hip extension, hip range of motion (ROM), peak ankle plantar flexion and ankle ROM (All p values < 0.05). The participants walked with increased stride length and decreased cadence during neck level as compared to waist and chest level. They also showed increased ankle ROM and decreased hip ROM as the water depth rose from waist and chest to the neck level. However, our study found no significant difference between waist and chest level water in all variables. Hydrodynamics, such as buoyancy and drag force, in response to changes in water depths, can affect gait patterns during aquatic treadmill walking.  相似文献   

The biomechanical characteristics of high-performance endurance running     

Stephen J. Preece  Christopher Bramah  Duncan Mason 《European Journal of Sport Science》2019,19(6):784-792

The biomechanical profile of high-level endurance runners may represent a useful model that could be used for developing training programmes designed to improve running style. This study, therefore, sought to compare the biomechanical characteristics of high-performance and recreational runners. Kinematic and kinetic measurements were taken during overground running from a cohort of 14 high-performance (8 male) and 14 recreational (8 male) runners, at four speeds ranging from 3.3 to 5.6?m?s^?1. Two-way ANOVA analysis was then used to explore group and speed effects and principal component analysis used to explore the interdependence of the tested variables. The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group. The high-performance group were also observed to adopt a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment. Importantly, although observed group differences were mostly independent of speed, the tested variables showed a high degree of interdependence suggesting an underlying unitary phenomenon. This is the first study to compare high-performance and recreational runners across a full range of kinematic and kinetic variables. The results suggest that high-performance runners maintain stride length with a prolonged aerial phase, rather than by landing with a more extended knee. These findings motivate future intervention studies that should investigate whether recreational runners could benefit from instruction to decrease shank inclination at foot contact.  相似文献   

Investigating Identity: Gender,Overseas Experience,and Japanese Youth     

Erina Ogawa 《Journal of Intercultural Communication Research》2019,48(3):185-202

Identity is prominent in academia, despite it being difficult to define and measure due to its dynamic and multifaceted nature. In Japan, awareness of the make-up of Japanese youth is increasingly crucial as Japan becomes a more internationalized and ageing society. This paper examines, by identity mapping and discriminant analysis, the cultural identities of 94 Japanese youth. While strong Global identities separated the respondents with from without overseas experience, ties to National identities and Relationships were found respectively for males and females. This paper suggests that regarding the study of cultural identities, gender does matter – at least in Japan.  相似文献   

2017年世界男排联赛中国男排与对手比赛技术效果对比分析          下载免费PDF全文

陈贞祥  赵德峰  沈琼 《体育科研》2019,(2):97-108

通过对比分析在2017年世界男排联赛上中国男排与对手在比赛中的整体技术效果、3站比赛间中国男排自身的技术效果及各站对手的技术效果，得出在劳尔教练任期的第一次世界大赛中国男排技术效果上的优势与不足，为其日后训练比赛提供数据参考和建议。研究发现：中国男排在发球、一传和防守技术效果上显著差于对手，一攻和反攻技术效果略差于对手，仅拦网技术效果显著好于对手。发现中国男排存在如下问题：（1）发球技术能力与外教战术意图不匹配，且缺少沟通；（2）一传稳定性差，顶不住大力发球冲击成为被对手制约的短板，且一传的差距直接转化为一攻的差距表现出来；（3）二传传平拉开球速度不够快，导致战术进攻意图过于明显；（4）比赛中拦网技术存在补拦意识仍不够、移动跟不上、拦一点放弃了两点的不足；（5）防守队员预判能力不够，下蹲过浅造成移动慢，从而对拦起球的保护跟不上。此外，研究还就3站比赛进行分类对比分析，得出了相应结论与建议。  相似文献   

Where are all the males? Gender-specific typologies of childhood adversity based on a large community sample     

《Child abuse & neglect》2019

BackgroundMethodological issues have been identified when quantifying exposure to adversity and abuse. To address a single type may obscure covarying effects. To sum multiple exposures gives equal weight to each. Latent class analysis (LCA) addresses this by identifying homogenous subpopulations. Most studies using LCA have pooled gender data in spite of evidence that the nature and frequency of exposure differs by gender. Males report more interpersonal abuse, females report more of other exposures, particularly sexual.ObjectiveThis study aimed to identify if stratifying data by gender resulted in different profiles of adversity/abuseParticipants and setting: The National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) wave II, a large community-based survey, nationally representative of the US population.MethodThis study used 14 indicators of childhood adversity as the basis for LCA.ResultsThe number and nature of classes differed by gender. The best solution for females was 4-class: a low risk class; a class at higher risk of sexual abuse; a class at higher risk of physical abuse; a class at higher risk of combined physical and sexual abuse. The best solution for males had only 3-classes; a low risk class, a class at higher risk of sexual abuse; a class at higher risk of physical abuse. The combined dataset resulted in a solution similar to the female solution.ConclusionThe importance of developing models for males and females separately was evidenced by the male and female classes being differentially associated with mental health variables.  相似文献   

对韩国文献太极拳理论研究的计量学分析*     

焦〓春  李爱增 《广州体育学院学报》2019,(1):60-64

太极拳是我国首批非物质文化遗产，作为中国传统民族特色的文化形态，近年来也越来越受到世界各国人民的喜爱，在世界范围内影响广泛、传播迅速。通过对韩国学术界的太极拳文献进行计量学统计分析，着重分析了文献的发表时间、作者、发行单位、研究主题和研究方法，旨在研究太极拳在韩国的发展史和传播过程，从社会学、文化学、体育学、传播学等角度，探索太极拳在异国推广和传播的规律及有效的推广方法，以期太极拳在世界大舞台上发扬光大，将太极拳的正能量传播到世界的各个角落。  相似文献   

Twenty-four-hour movement behaviours and fundamental movement skills in preschool children: A compositional and isotemporal substitution analysis     

Jéssica Gomes Mota  Cain Craig Truman Clark  Luís Lemos  Cézane Priscilla Reuter  Jorge Augusto Pinto Silva Mota 《Journal of sports sciences》2020,38(18):2071-2079

ABSTRACT

Studies that have analysed the association between the different movement behaviours and fundamental movement skills (FMS) have considered it in an independent manner, disregarding the compositional nature of 24-h movement behaviours (24-h MB). The aim of this study was to investigate the relationship between the 24-h MB and FMS in preschoolers using a compositional data analysis . Two hundred and four preschoolers (4.5 ± 0.8 years old; 101 boys) provided objectively assessed physical activity (PA) and sedentary behaviour (SB) data (Actigraph wGT3X), and FMS (TGMD-2). Sleep duration (SD) was reported by parents. Association of daily composition of movement behaviours with FMS was explored using compositional analysis and isotemporal substitution (R Core Team, 3.6.1). When considered as a 24-h MB composition (PA, SB and SD), adjusted for age, BMI and sex, the composition predicted locomotor (r² = 0.31), object control (r² = 0.19), and total motor score (r² = 0.35), respectively (all P < 0.001). Reallocation of time from light to moderate-to-vigorous PA was associated with greatest positive changes in total motor score. Achieving adequate balance between movement behaviours over the 24-h period, and its relationship with locomotor and object control skills should be considered and further investigated in early childhood.  相似文献   

形意拳柔性思想的教学理念分析     

张国栋  王文清 《中华武术(研究)》2020,(3):95-97

形意拳历来以刚猛粗扩、实战性强著称,随着时代发展,形意大师布学宽提出的形意拳柔化教学思想被逐漸认同。本文从现代教育学的角度,结合形意拳自身特点及现代教育教学理论,探讨形意拳柔性思想下的教学理念,为形意拳由竞技拳转变为健身拳、文化拳的柔性思想教学提供参考和借鉴。  相似文献