The biomechanical characteristics of high-performance endurance running

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.     

No effect of HMB or α-HICA supplementation on training-induced changes in body composition

β-hydroxy-β-methylbutyrate (calcium: HMB-Ca and free acid: HMB-FA) and α-hydroxyisocaproic acid (α-HICA) are leucine metabolites that have been proposed to improve body composition and strength when combined with resistance exercise training (RET). In this double-blind randomized controlled pragmatic trial, we evaluated the effects of off-the-shelf supplements: α-HICA, HMB-FA and HMB-Ca, on RET-induced changes in body composition and performance. Forty men were blocked randomized to receive α-HICA (n?=?10, fat-free mass [FFM]?=?62.0?±?7.1?kg), HMB-FA (n?=?11, FFM?=?62.7?±?10.5?kg), HMB-Ca (n?=?9, FFM?=?65.6?±?10.1?kg) or placebo (PLA; n?=?10, FFM?=?64.2?±?5.7?kg). The training protocol consisted of a whole-body resistance training routine, thrice weekly for 8 weeks. Body composition was assessed by dual-energy x-ray absorptiometry (DXA) and total body water (TBW) by whole-body bioimpedance spectroscopy (BIS), both at baseline and at the end of weeks 4 and 8. Time-dependent changes were observed for increase in trunk FFM (p?相似文献   

女性私人健身教练从业限制因素模型构建与分析

运用文献资料法、调查法和逻辑分析法,对女性私人健身教练从业限制因素进行研究。利用访谈和问卷调查获得的数据,构建了女性私教从业限制因素的结构模型,并采用验证性因素分析对模型进行检验。结果显示：限制女性私教从业的因素主要包括个人限制因素、人际限制因素和企业限制因素,构建的三因素结构模型各项指标拟合度良好,结构稳定,可以为促进女性私人健身教练从业提供参考。进而从三个因素的角度,提出促进女性私教从业的建议,包括女性私教合理规划个人职业生涯,坚定从业信念;家人、同伴转变观念,提升女性私教的社会支持;健身企业切实履行对员工的社会责任,增强女性私教的工作满意度和企业认同感。     

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

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。     

大众化背景下一般高校的区域化发展

大众化背景下,办学的特色化和个性化、构建核心竞争力、强化区域服务功能和拓展办学空间,已成为高等学校所追求的重要目标。一般地方高校应根植于区域发展的需要,培育具有区域特征的办学特色;立足区域特色培育核心竞争力;培育具有区域特色的科研方向,依托区域特色提升科研层次;不断推动区域特色的国际化,力争把区域特色打造成国际品牌。     

早期阶段创新项目的财政资助政策研究

在激励理论的分析框架下对早期阶段创新项目的财政资助政策进行了研究,主要结论包括:1)为担保创业企业家的努力投入,创新企业必须投入足够的自有资本才能吸引创业资本的进入,因此政府的财政资助可以弱化创新企业的财富约束,从而激励更多的创新活动;2)要求按比例分享项目收益的有偿资助方式帕累托劣于无偿资助,而仅要求固定回报的有偿资助则是激励中性的。根据上述结论进一步解释了创业投资家在投资项目选择上的阶段偏好现象,并分析了天使投资的矛盾性,证明了在对早期阶段创新项目的扶持中,公共资本起着不可替代的作用。     

江苏省战略性新兴产业发展的金融支持研究*

战略性新兴产业的培育与发展离不开金融业的支持。但由于战略性新兴产业的自身特性及其金融需求与传统融资模式之间存在着一定的不匹配性,导致当下金融业在支持战略性 新兴产业发展上仍存在一些问题。本文在分析江苏省战略性新兴产业金融支持现状基础上,以22家江苏省战略性新兴产业上市公司为例建立面板数据模型,通过实证分析发现：留存收益融资和商业信用融资对江苏省战略性新兴产业发展起正向支持作用,而银行信用融资和股权融资对江苏省战略性新兴产业发展起负向支持作用,债券融资对江苏省战略性新兴产业发展的作用则不显著。总之金融对江苏省战略性新兴产业的支持作用尚未得到充分发挥,金融支持效率偏低。由此从政策性金融、银行信贷、资本市场以及风险投资等四个维度系统提出金融支持江苏省战略性新兴产业发展路径的政策建议。     

基于时间聚类的加权关联规则及其在企业中的应用

针对煤炭企业采用的基于关联规则的数据挖掘技术存在的不足,文章提出了一种基于时间聚类的加权关联规则挖掘算法,分析了关联规则的基本概念,简要介绍了传统Apriori算法原理,详细介绍了基于时间聚类的加权关联规则挖掘算法原理及实现．实际应用范例表明,与Apriori算法相比,基于时间聚类的加权关联规则挖掘算法具有较高的准确性．     

土钉与槽钢组合支护在软土深基坑中的应用

在高层建筑深基坑支护各种方案中,通常土钉支护费用最低,当深基坑土质条件较差,如沿海地区淤泥质土层,含水量较大,基坑垂直支护面难以成型,难以采用土钉支护方案,引用钢板桩支护原理,本文采用25号槽钢与土钉组合深基坑支护方案,解决土钉在软土中应用不足和发挥槽钢封面的特点,成功解决软土地区土钉支护问题,由于槽钢可以全部回收重复使用,该支护方案造价较低,经济效益较好。     

Fault diagnosis model based on fuzzy support vector machine combined with weighted fuzzy clustering

A fault diagnosis model is proposed based on fuzzy support vector machine (FSVM) combined with fuzzy clustering (FC).Considering the relationship between the sample point and non-self class,FC algorithm is applied to generate fuzzy memberships.In the algorithm,sample weights based on a distribution density function of data point and genetic algorithm (GA) are introduced to enhance the performance of FC.Then a multi-class FSVM with radial basis function kernel is established according to directed acyclic graph algorithm,the penalty factor and kernel parameter of which are optimized by GA.Finally,the model is executed for multi-class fault diagnosis of rolling element bearings.The results show that the presented model achieves high performances both in identifying fault types and fault degrees.The performance comparisons of the presented model with SVM and distance-based FSVM for noisy case demonstrate the capacity of dealing with noise and generalization.