基于TSM模型的感应电机有限时间跟踪控制

根据变结构控制理论提出了一种新的设计方法——有限时间切换控制。在控制器设计中利用中继切换控制使系统在给定的当前控制律的作用下运行到某一特定状态（或某一特定区域）后,控制律被切换为有限时间收敛的终端滑模控制器,并使得系统在有限时间内达到平衡状态。有限时间跟踪控制器的设计保证了闭环系统所有信号的有界性和平衡点的全局稳定性,以及系统在有限时间内精确地跟踪给定的参考信号,仿真结果说明该控制策略的有效性。     

运动与丝裂原活化蛋白激酶信号系统的研究动态

丝裂原活化蛋白激酶信号系统(mitogen activated protein kinase，MAPKs)在细胞的信号传导中起着很重要的作用。其中以ERK1／2、JNK／SAPK、p38研究得最为深入。运动能够激活骨骼肌中MAPKs信号传导系统。不同运动方式、不同类型的肌肉可以影响到MAPKs的激活，而且激活后MAPKs具有不同的时相性。MAPKs对运动后骨骼肌的适应性变化具有重要作用。     

机械生长因子(MGF)与运动

机械生长因子MGF（Mechano Growth Factor）起源于胰岛素生长因子1（IGF-1），是IGF-1基因经过不同剪切而衍生的。MGF的表达主要受机械刺激和组织损伤的影响，且比肝型IGF-1具有潜在的增加肌肉质量的能力。为更好认识MGF在肌肉生长中的作用，对MGF的生物学作用，以及运动、激素对MGF的影响进行综述。     

负重训练和补充大豆多肽干预大鼠骨骼肌衰老过程的实验研究

目的:探讨负重训练和补充大豆多肽干预大鼠骨骼肌衰老过程的作用效果.方法:56只雄性SD大鼠随机分为7组:成年组,模型组,D-半乳糖小负重组,D-半乳糖大负重组,D-半乳糖补肽组,D-半乳糖补肽小负重组,D-半乳糖补肽大负重组.6周后处死大鼠,制作冰冻切片,测试血清以及骨骼肌各项指标.结果:与成年组相比,模型组大鼠体重和每日摄食量分别呈现升高和下降的趋势,负重和补肽可以在一定程度上缓解两种趋势,但都无统计学意义;模型组大鼠骨骼肌细胞出现萎缩和退行性改变等衰老的迹象,负重和补肽可以在一定程度上减轻这种现象;模型组大鼠血清SOD、SOD/MDA比值和骨骼肌总蛋白含量显著低于成年组,血清MDA显著高于成年组,运动和营养干预各组显著逆转这种趋势,并有明显的交互作用;与成年组相比,模型组大鼠骨骼肌脂褐素含量显著升高,负重或补肽可以一定程度上缓解或逆转这种趋势,两种具有明显的交互作用.结论:负重训练或补充大豆多肽均可以有效的预防大鼠骨骼肌衰老过早的出现,两种方式联合运用效果更为明显.     

大强度间歇运动骨骼肌分子适应机制

大强度间歇运动可能代表一个独特的运动方式,充分认识大强度间歇运动诱导骨骼肌分子适应机制非常助于制定相关的训练方法。大强度间歇运动特征为短暂的间歇性肌肉收缩。当前研究表明大强度间歇运动诱导骨骼肌的表型变化可能和传统耐力训练一致。但不同运动方式激活信号途径可能存在信号间交互方式、前反馈和后反馈调节等。因此,尚需大量的研究证实。     

Creatine supplementation does not decrease oxidative stress and inflammation in skeletal muscle after eccentric exercise

Abstract

Thirty-six male rats were used; divided into 6 groups (n = 6): saline; creatine (Cr); eccentric exercise (EE) plus saline 24 h (saline + 24 h); eccentric exercise plus Cr 24 h (Cr + 24 h); eccentric exercise plus saline 48 h (saline + 48 h); and eccentric exercise plus Cr 48 h (Cr + 48h). Cr supplementation was administered as a solution of 300 mg · kg body weight^?1 · day^?1 in 1 mL water, for two weeks, before the eccentric exercise. The animals were submitted to one downhill run session at 1.0 km · h^?1 until exhaustion. Twenty-four and forty-eight hours after the exercise, the animals were killed, and the quadriceps were removed. Creatine kinase levels, superoxide production, thiobarbituric acid reactive substances (TBARS) level, carbonyl content, total thiol content, superoxide dismutase, catalase, glutathione peroxidase, interleukin-1b (IL-1β), nuclear factor kappa B (NF-kb), and tumour necrosis factor (TNF) were analysed. Cr supplementation neither decreases Cr kinase, superoxide production, lipoperoxidation, carbonylation, total thiol, IL-1β, NF-kb, or TNF nor alters the enzyme activity of superoxide dismutase, catalase, and glutathione peroxides in relation to the saline group, respectively (P < 0.05). There are positive correlations between Cr kinase and TBARS and TNF-α 48 hours after eccentric exercise. The present study suggests that Cr supplementation does not decrease oxidative stress and inflammation after eccentric contraction.     

Skeleton Changes Induced by Horse Riding on Medieval Skeletal Remains from Croatia

Skeletal remains of 35 individuals from the Croatian excavation site Kamen Most – Kaldrma from the fourteenth to fifteenth centuries were analyzed anthropologically. Due to specific skeletal characteristics, eight of them were analyzed in great detail in this study. The results of additional analysis indicated that all bone elements, except pelves, of all eight persons belonged to males. All pelvic girdle have characteristics of female sex and pronounced muscle attachments that are both indicative of horse riding. All eight persons had at least two of six changes on femora indicative of horse riding. Vertebrae of seven persons (one person did not have preserved vertebrae) have Schmorl's nodes. Signs of advanced osteoarthritis were found on all joints in all eight persons. All of them also have visible signs of periostitis especially on lower extremities. Pathological signs of trauma were found in five persons. Two of them had skull fractures and the rest had fractures of extremities which are also characteristic for horse riders. The average age of all eight persons was above 45 years at death. DNA analysis confirmed male sex for seven individuals. The results were additionally confirmed by later archeological findings of tombstones with illustrations of horse riders.     

骨骼肌基因转移系统的建立

以EGFP为标记基因，利用重新构建的pAV-EGFP质粒，采用直接注射方法，进行了离体和在体基因转移研究。实验结果显示，经脂质体包裹后，质粒可以有效地进行细胞转移；DNA表达载体肌肉直接注射后，利用共聚焦显微镜可以在注射点周围的肌细胞观察到绿色荧光蛋白；而在对侧肢PCR和共聚焦显微镜的结果均为阴性。实验结果表明，肌肉直接注射DNA可以在肌肉得到表达，将会为治疗肌肉损伤带来新的方法。     

视觉运动追踪及其在体育运动中的应用与启示

运动员的视觉运动追踪能力是众多运动项目获得优异比赛成绩的关键因素,也是近些年运动心理学研究的重要问题。运用文献综述法对国内外关于视觉运动追踪的基本理论、研究范式及其在体育运动中的应用进行剖析,总结以往研究所取得的成果和存在的不足,探讨视觉运动追踪研究对体育运动成绩的影响与启示,为后续相关研究提供一定的思路与方法借鉴,为运动员心理选材及心理技能训练方法与策略提供理论参考和实证依据。     

Validity of Self-Reported Pedometer Steps per Day in College Students

The purpose of this article was to examine the validity of self-reported pedometer steps/day. Forty-seven participants were provided a New Lifestyles NL-2000 (NL-2000; Lees Summit, MO, USA) pedometer and a physical activity (PA) diary for 3 weeks, but not informed of the data-storing capabilities. For weeks 2 and 3, each participant was given a step goal of 3,000 steps/day above week 1 average. A 2 × 3 repeated measures analysis of variance (ANOVA) was used to examine differences between reported steps/day. Bland–Altman plots assessed the mean bias and limits of agreement between reporting methods. Mean self-reported and NL-2000 steps/day were 9,264 ± 3,555 and 8,971 ± 3,590 steps/day (n = 26, p > .05). Mean biases were 216 ± 1,753 (week 1), –506 ± 1,355 (week 2), and –590 ± 1,360 (week 3) steps/day. Negative mean bias values indicate higher self-reported steps/day. Mean steps/day were similar between recording methods, but large differences were observed among individuals, suggesting self-reported steps/day may be valid for PA research at the population level, but not the individual level.