Effect of individualized resistance training prescription with heart rate variability on individual muscle hypertrophy and strength responses

Abstract

The aim of the present study was to investigate if resistance training (RT), performed with individualized recovery between sessions (RT-IND), promotes greater gains in strength and muscle mass and reduces the variability on adaptations compared to RT with fixed recovery intervals (RT-FIX). Twenty young men (age 21.9?±?3.3 years) were randomized in the RT-IND and RT-FIX groups. Five days before the beginning of the training, measurements of the root mean square of successive R-R intervals differences (RMSSD) values of each individual were performed to establish the baseline values. Before each RT session, the RMSSD values determined whether the participants from RT-IND protocol were recovered from the previous session. Participants performed the RT session only if RMSSD values had returned to the baseline, otherwise they had to wait for an additional 24?h. RT-FIX performed an RT session every 48?h. Muscle strength was measured by one-maximal repetition (1-RM) test and muscle cross-section area (CSA) of the vastus laterals by ultrasonography were assessed pre- and post-training. 1-RM values increased significantly from pre to post-training for both groups (RT-IND: 30% and RT-FIX: 42%, main time effect, P?<?0001), with no significant difference between groups. Muscle CSA increased significantly from pre to post-training (RT-IND: 15.7% and RT-FIX: 15.8%, main time effect, P?<?0001), with no significant difference between groups. In conclusion, RT-IND did not increase the gains in muscle strength and mass neither reduce the variability in muscle adaptations when compared to the RT-FIX.     

导引术对大学生健身理念的启示

文章运用文献资料法和对比分析法,发现近年来大学生学习和就业等压力大及身体运动不足等原因,从而导致身体素质逐年下降。通过对中国传统导引术的理论研究与分析,探索其对大学生的身体发展产生的良好影响,为大学生提供优质的健身理念,以促进大学生的身体健康。     

The Effects of Using Concept Mapping for Improving Advanced Level Biology Students' Lower- and Higher-Order Cognitive Skills

This paper reports on teachers' use of concept mapping as an alternative assessment strategy in advanced level biology classes and its effects on students' cognitive skills on selected biology concepts. Using a mixed methods approach, the study employed a pre-test/post-test quasi-experimental design involving 156 students and 8 teachers from intact classes. A researcher-constructed Biology Cognitive Skills Test was used to collect the quantitative data. Qualitative data were collected through interviews and students' personal documents. The data showed that the participants utilized concept mapping in various ways and they described positive experiences while being engaged in its use. The main challenge cited by teachers was the limited time available for more consistent use. The results showed that the use of concept mapping in advanced level biology can lead to learning gains that exceed those achieved in classes where mainly traditional methods are used. The students in the concept mapping experimental groups performed significantly better than their peers in the control group on both the lower-order (F₍₁₎?=?21.508; p?<?.001) and higher-order (F₍₁₎?=?42.842, p?<?.001) cognitive items of the biology test. A mean effect size of .56 was calculated representing the contribution of treatment to the students' performance on the test items.     

伴流场中大侧斜桨无空化水动力和噪声的尺度效应分析(英文)

针对艇尾伴流场中大侧斜桨无空化水动力和水声性能的尺度效应问题,对几何相似但直径分别为250,500和1000mm的七叶大侧斜桨的无空化线谱噪声及其标准化谱曲线经验公式和总声压级进行了分析.噪声预报同时采用频域和时域计算2种方法.作为脉动噪声源的桨叶表面脉动压力和法向速度分布由URANS模拟得到.结果表明,在相同进速系数下3种尺度桨的0.7R截面压力系数分布重合度高;3个桨的推力脉动均能准确地反映出轴频和叶频信息,且中桨相对于小桨在叶频处的推力脉动幅值增量较大桨相对于中桨要大.2种噪声预报方法得到的大桨相对于小桨的总声级增量相差2.49dB;大桨和中桨标准化谱曲线较为一致,但与小桨差异明显.随着直径的增加,线谱谱级和总声级增量增加.建议应尽可能增大模型桨的几何尺度,以减小经验公式的预报误差和尺度效应影响.     

基于混频MF-VAR模型的中国海洋经济增长研究

由于中国海洋经济相关指标月度数据和季度数据未定期公布,所以以年度低频海洋经济样本数据进行分析时会因样本数据过短而结果不精确。本文构建了海洋经济增长混频MF-VAR模型,根据2005-2013年中国海洋经济增长实时数据对模型进行最优选取和参数估计,与基准模型进行测度对比,探索混频数据模型在海洋经济领域的应用。研究结果表明：①MF-VAR模型在测度中国海洋经济增长方面误差相对较小,且多变量MF-VAR模型拟合效果优于GOP与CIFA、GOP与VFH的单变量MF-VAR模型,说明海洋经济的周期波动受到各方面因素的影响,仅是影响程度大小不同;②相对于基准模型,MF-VAR模型在短期预测方面具有精准性的比较优势,随着预测步数的增加,估计和预测精度下降;③不论是单变量还是多变量MF-VAR模型,估计和预测的MSE均低于对应同频数据基准模型,因此混频数据模型不仅可以解决样本长度较短的问题,而且在提取海洋经济高频数据信息方面具有显著优势,可提高海洋经济分析的准确度和及时性。     

基于词频、词量、累积词频占比的共词分析词集范围选取方法研究

[目的/意义]提出一种基于词频、词量、累积词频占比三者变化关系的共词分析词集范围的确定方法,尝试对现有词集范围选取方法中仅凭经验判断和过度依赖词频为“1”的关键词的问题进行改进,为相关研究提供一种更加规范、科学、值得借鉴的做法。[方法/过程]该方法充分考虑词集实际分布规律和特点,将词或词组分类成高、中、低频,并选择高、中频词共同作为共词分析的对象。[结果/结论]通过在具体领域的实例验证以及与其他方法的对比,证明该方法可以有效地选择合适的词集范围,对今后相关研究具有一定借鉴意义。     

改进TF-IDF算法的文本特征项权值计算方法

首先,从特征项重要性和类别区分能力的角度出发,通过分析传统的权重函数TF-IDF(term frequency-inverse document frequency)及其相关改进算法,研究文本分类中向量化时的特征权重计算,构建权重修正函数TW。其次,通过对特征词的卡方分布和TW作对比实验,验证TW能提高类别中专有词汇的权值,降低常见但对分类不重要的特征的权值。最后,将TW与TF-IDF结合作为新的特征权重算法,通过在中文分类语料库上的实际分类实验,与其他权重算法比较,验证此种算法的有效性。     

2000-2011年中国图情研究主题的“变”与“不变”——以《图书情报工作》刊发的论文为样本

以《图书情报工作》2000-2011年刊发的论文为样本,以高频词和知识图谱为考察视角,发现图书馆学情报学相对"不变"的主题域主要有5个:数字图书馆、学科信息服务、竞争情报与知识管理、图书馆学与情报学理论研究和文献计量学研究。以关键词历年频次变化为考察视角,分别挖掘出最近6年新兴主题、增幅明显主题、消失主题及降幅明显主题若干,并筛选出30个左右"突现词"作为最具"变"的意味的关键词,以考察图书馆学情报学的情境性演变。研究发现《图书情报工作》热切关注前沿主题,在某种程度上引领着我国图书馆学情报学的发展方向。     

参考咨询研究主题的演变和趋向——基于1998-2012年CSSCI数据的分析

以CSSCI数据为来源,运用文献计量法,从论文时间分布、作者分布和关键词分布等维度,统计分析1998-2012年我国参考咨询领域的研究成果,揭示高频关键词出现、转移和消失的现象及其变化规律,从中探讨参考咨询研究主题的演变和发展趋向,以期为相关领域的研究方向带来价值判断和理论支撑,为我国图书情报机构提高参考咨询服务水平提供参考。