间歇性低氧训练对气体代谢影响的实验研究

间歇性低氧训练是 90年代初在俄罗斯率先发展的一种新的科学训练方法 ,在运动训练中发挥了积极有效的作用。笔者通过人体实验 ,探讨间歇性低氧训练对气体代谢及运动耐力的影响 ,为该训练方法在我国的推广应用提供必要的理论 ,实践依据。实验结果表明 :间歇性低氧训练可有效提高呼吸系统功能 ,提高气体代谢效率 ,促进运动能力提高 ,是一种科学有效的训练方法     

在职体育教师培训路径的思考

为适应新世纪高校体育教学改革需求，有效提高体育教学质量，对在职体育教师的培训必须综合考虑时间、经费和效果三方面的因素，制定出切实可行的培训方案除校内交流外，走出去与请进来相结合的基本思路是拓宽专业口径，拔高专业水平的有效措施：以请进来为主的培训路径，辅之以形成学习型团队或组织、制定合理的培训考核制度，将会在短期内提高在职体育教师整体的专业水平，拓宽专业口径，以解目前体育教学中存在的燃眉之急。     

地球辐射带的膨胀和收缩Ⅱ

本文论述地球辐射带的膨胀和收缩的范围:当地球从近日点运动到远日点时,地球辐射带向外膨胀;当地球从远日点运动到近日点时,地球辐射带向内收缩。其膨胀或收缩范围是:第一层辐射带大约为30m,第二层辐射带大约为80m。     

远距离单手肩上投篮训练方法探讨

讨论影响投篮命中率有7个因素:手法、瞄准的方向、球的旋转、抛物线、协调性、判断反应和心理因素,并提出提高远距离投篮命中率的训练方法.     

范德瓦耳斯气体的临界指数β=1/3

从范德瓦耳斯气体的对比态方程出发,推导出临界指数的数值为1/3,与实验值相近。     

The Issue of Range Restriction in Bookmark Standard Setting

This article uses data from a large‐scale assessment program to illustrate the potential issue of range restriction with the Bookmark method in the context of trying to set cut scores to closely align with a set of college and career readiness benchmarks. Analyses indicated that range restriction issues existed across different response probability (RP) values and item response theory (IRT) models if one were to apply the Bookmark procedure using intact test forms. Results also suggested that range restriction may still be present if one had access to additional data from an item bank. This demonstration critically highlights challenges that may exist in some practical applications of the Bookmark method due items not being designed to cover the full range of examinee abilities.     

欧盟基本法的本质

欧盟基本法是欧盟法律的主要渊源。欧盟基本法在欧盟法律体系中具有宪法的三个最基本特征,即地位具最高性,内容具根本性,程序具严格性,在欧盟法律体系中实际上起着宪法的作用。     

新型氧气-丙烷气割嘴

与乙炔相比,无论工作性能还是气源条件,丙烷都具有相当的优势.介绍了一种新型氧气-丙烷气割嘴,以改进传统的采用氧气-乙炔的气割方式,并采用F luent软件对氧气-丙烷的混合情况进行了数值模拟,结果显示割嘴出口速度场分布均匀,氧气-丙烷的混合情况对燃烧有利,证明此种割嘴形式具有较好的混气效果.     

焦耳定律的非独立性问题

本文指出有关焦耳定律非独立性的证明中仍存在的问题，并给出新的证明．     

Hip and upper extremity kinematics in youth baseball pitchers

The purpose of this study was to examine the relationship between dynamic hip rotational range of motion and upper extremity kinematics during baseball pitching. Thirty-one youth baseball pitchers (10.87 ± 0.92 years; 150.03 ± 5.48 cm; 44.83 ± 8.04 kg) participated. A strong correlation was found between stance hip rotation and scapular upward rotation at maximum shoulder external rotation (r = 0.531, P = 0.002) and at ball release (r = 0.536, P = 0.002). No statistically significant correlations were found between dynamic hip rotational range of motion and passive hip range of motion. Hip range of motion deficits can constrain pelvis rotation and limit energy generation in the lower extremities. Shoulder pathomechanics can then develop as greater responsibility is placed on the shoulder to generate the energy lost from the proximal segments, increasing risk of upper extremity injury. Additionally, it appears that passive seated measurements of hip range of motion may not accurately reflect the dynamic range of motion of the hips through the progression of the pitch cycle.