Peak muscle activation, joint kinematics, and kinetics during elliptical and stepping movement pattern on a Precor Adaptive Motion Trainer

Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = .01), 29% more knee extension (p = .003), 101% higher peak knee flexor moments (p < .001) 54% greater hip extensor moments (p < .001), 268% greater anterior joint reaction force (p = .009), 37% more RF activation (p < .001), and 200 % more ES activation (p <. 001) for the elliptical motion. Sixteen percent more hip flexion (p < .001), 42% higher knee extensor moments (p < .001), and 54% greater hip flexor moments (p = .041) occurred during the step motion. Biomechanical differences between motions should be considered when planning an exercise regimen.     

师爱如山

看到一个个儿童在废墟中卷曲着身子，稚嫩的脸上满是尘土，看到那一个个书包已经失去主人，我这几天内心如焚，眼泪也烧干了，默默地祈祷，祈祷他们的纯洁灵魂升入天堂安息。     

Experimental and theoretical evidences for the formation of transition metal complexes with five coplanar metal–carbon σ bonds

The σ bond is an important concept in chemistry, and the metal–carbon(M–C) σ bond in particular is a central feature in organometallic chemistry. Synthesis of stable complexes with five coplanar M–C σ bonds is challenging. Here, we describe the synthesis of two different types of stable complexes with five coplanar M–C σ bonds, and examine the stability of such complexes which use rigid conjugated carbon chains to chelate with the metal center. Density functional theory(DFT) calculations show th...     

The associated evolution of raptorial foreleg and mantispid diversification during 200 million years

<正>Adaptive evolution of predatory structure grants carnivores selective advantages[1], which evokes questions regarding the mechanism of functional adaptation via morphological variation and their potential impact on lineage diversification. Raptorial foreleg, as a key predatory structure in insects, is typically characterized by elongate coxae and stout femora possessing spines, and has evolved independently in many lineages [2].     

Two-dimensional superconducting MoSi2N4(MoN)4n homologous compoundsOA

The number and stacking order of layers are two important degrees of freedom that can modulate the properties of 2D van der Waals(vdW) materials. However, the layers’ structures are essentially limited to the known layered 3D vdW materials. Recently, a new 2D vdW material, MoSi₂N₄, without known 3D counterparts, was synthesized by passivating the surface dangling bonds of non-layered 2D molybdenum nitride with elemental silicon, whose monolayer can be viewed as a monolayer ...     

Level pinning of anti-PT-symmetric circuits for efficient wireless power transferOA

Wireless power transfer(WPT) technology based on magnetic resonance(a basic physical phenomenon)can directly transfer energy from the source to the load without wires and other physical contacts, and has been successfully applied to implantable medical devices, electric vehicles, robotic arms and other fields.However, due to the frequency splitting of near-field coupling, the resonant WPT system has some unique limitations, such as poor transmission stability and low efficiency. Here, we propose...     

中国的大学教育与高考制度

一、中国大学的“英才”教育按照美国教育学家 M·特罗根据历史的发展把高等教育制度历史发展过程分为“英才”、“大众”和“普及”三个阶段,英才教育的大学制度只能容纳同龄人中2—5%青年,在大学收纳不超过15%的同龄人口以前,高等教育对象在很大程度上是精英分子,大学就是以精英主义原则组织的。一方面,社会及其高等教育认为进入大学的人本来就是精英;另一方面,大学不但促使这些精英的成长,而且也分配了社会的高等教育资源,使     

基于SECI的城市商业休闲体育组织知识管理初探

伴随奥运经济后续效应,体育休闲消费也将成为城市居民的新宠,因此,各种商业体育休闲组织的涌现势不可挡.然而,当前知识经济形态的存在,使得知识成为组织进行市场竞争的法宝,这对商业体育休闲组织的管理提出新的要求.研究试图以日本管理学家Nonaka和Konno所提出的SECI模型为基础,主要对商业体育休闲组织及其实施知识管理的必要性以及如何搭建知识管理系统平台等问题逐一进行探讨.     

我国休闲体育产业集群的壁龛性及其市场拓展的衍生路径探究

首次以壁龛特性为视角,将我国休闲体育产业集群分为以依托于其他产业类型为主和以依托于大型体育赛事而集聚起来的休闲体育产业集群两大类,研究发现这两类休闲体育产业集群具有明显的共性--嵌入并依附于其他市场的小壁龛市场特征.那么,如何促进其进一步发展,文章借助社会网络分析法中的弱关联和强关联,提出了我国壁龛型休闲体育产业集群产生和进一步拓展市场的路径衍生模型.