下坡跑运动对骨骼肌α7β1整合素及FAK表达的影响

通过观察下坡跑运动后α7β1整合素及FAK的表达和FAK活性的变化,探讨α7β1整合素在运动重复效应中作用机制。将32只小鼠随机分为安静对照组,运动后3 h组、24 h组、8 d组。小鼠进行一次性下坡跑运动,速度为17 m/min,坡度为-20°,时间为30 min。各组于各时刻点摘眼球取血及取双侧腓肠肌。比色法检测血清CK活性,Real-time PCR检测α7β1整合素及FAK的m RNA表达,Western blot检测α7β1整合素及p FAK397的蛋白表达。结果显示一次下坡跑运动后CK活性升高显著,且在24 h增幅增大。α7 integrin m RNA在一次运动后3 h显著增加,但在24 h变化不明显,但8 d时仍增加显著,其蛋白水平在运动后3 h显著增加,虽在24 h和8 d时升高程度逐渐降低但仍呈显著。β1 integrin m RNA在一次运动后3 h显著增加,24 h及8 d变化不明显,蛋白水平在一次运动后3 h呈显著升高,24 h升高程度增加,在8 d时回复。FAK m RNA在一次运动后3 h显著增加,24 h及8 d变化不明显,p FAK397水平在一次运动后呈现显著升高,24 h升高程度降低,8 d时基本回复。结果表明α7β1整合素-FAK信号通路介导了运动重复效应。     

智能手机动作识别系统线性反馈控制算法

智能手机动作识别系统设计中,设计线性反馈控制算法,提高手机对动作识别的灵敏度和准确度。传统的智能手机动作识别控制算法采用分层子维空间运动规划,提出一种加权最小范数广义逆RRT规划算法,提出一种改进的智能手机动作识别系统线性反馈控制算法,但存在对智能手机动作识别控制精度不高,控制延迟较大等问题。为此,提出一种改进的智能手机动作识别系统线性反馈控制算法,进行了智能手机的动作识别系统模型构建,构建智能手机动作识别系统的运动方程。然后采用线性控制策略,提高对智能手机动作识别的稳定性和精确性,构建智能手机动作识别的闭环系统,求得动作控制矩阵两边相应的元素,构成时变时滞函数,得到改进的线性反馈控制输出。在算法设计的基础上,进行软件编译,在应用层运行Android的应用程序,由此实现了对智能手机的动作识别控制。仿真结果表明,设计的智能手机动作识别系统具有较好的控制精度,抗干扰能力较强,稳定性好,控制精度较高,能准确跟踪动作变化情况,避免了迟延控制和差错控制。     

主动肌肉收缩对缓解运动疲劳的实验分析

目的:研究主动肌肉收缩对缓解运动疲劳的作用,对人体的适当运动对缓解肌肉疲劳有一定的调节指导意义。传统的分析方法基于蛋白质的分析方法,通过对于人体中蛋白质的详细分析和测试,推理出人体主动肌肉收缩对缓解疲劳的机理分析,但只是结果定性分析,没有详细描述机体的肌肉收缩详细过程。方法:提出一种基于主动肌肉收缩特性的方法,通过实验测试了三种不同运动状态所造成的疲劳程度,等长训练,等张训练,等动训练下的训练特性与相应的主动肌肉收缩特性,并且调查分析了不同年龄段的人群对于主动肌肉收缩下的运动疲劳缓解调节能力。结果:实验结果表明,主动肌肉收缩能够在一定程度上降低运动的疲劳感,并且随着年龄的增长,疲劳缓解调节达到预期效果的比例在逐渐降低,同时主动肌肉收缩的机理特性也在降低。结论:主动肌肉收缩对缓解运动疲劳具有很好的指导意义。     

创业行动学习过程研究——基于新兴产业的多案例分析

随着新兴产业成为经济转型的重要动力,我国创业情境特征在发生变化:创业领域向新兴产业转移;经营模式往团队项目形式发展。聚焦于传统行业和个体学习行为的创业学习理论面临新挑战,创业学习的概念模型需要修正。基于创业学习与行动学习理论,本文提出创业行动学习新构思:创业者通过社会互动方式来解决创业问题进而促进学习的过程。遵循亲验学习理论,本文建构创业行动学习的过程框架,并采用多案例研究方法提炼该概念模型。通过对新兴产业三个创业案例的长期跟踪研究发现:创业行动学习受创业问题驱动,是由体验搜集、交互反思、系统整合和行动验证四个要素组成的螺旋上升模型。文章最后深入讨论该过程模型产生学习效果的机理。     

中国足协纪律处罚现状、问题与立法完善

通过对近三年中国足协纪律处罚实施情况的统计,可以看出纪律处罚被广泛运用,它在规范足球比赛秩序,维护公平竞争环境,促进足球运动健康发展方面发挥了重要的作用。但中国足协纪律处罚在规则制定、处罚程序、被处罚人权利救济等方面也存在着诸多问题,这既影响了纪律处罚作用的发挥,又不利于相对人合法权益的保护,同时也容易造成纪律处罚权的滥用。因此,有必要对中国足协纪律处罚予以完善。通过完善规则的制定,以保证规则的科学性、稳定性;通过保障相对人程序权利,以实现纪律处罚的公正性;通过建立完整的权利救济体系,明确不同救济机制的运行规则,防止权力滥用与权利侵害,这是完善中国足协纪律处罚的基本路径。     

不同时程下[Ca2+]i介导骨骼肌微细损伤与修复的机制及针刺的干预作用

目的:观察离心运动介导骨骼肌微损伤与修复过程,肌细胞不同微区钙离子浓度变化所起的作用,以及肌浆网钙释放通道兰尼定受体(RyR)的调控信号。方法:114只雄性SD大鼠,分为离心运动(E组,36只)、离心运动+针刺(EA组,36只)、单纯针刺(A组,36只)和安静对照(C组,6只)。E、EA和A组在运动后即刻、6、12、24、48、72 h取材,电镜观察结构,能谱分析Z线和H区钙元素,WB观察磷酸二酯酶-4-D3(PDE4D3)和FK506绑定蛋白12(FKBP12)表达。结果:E与EA组Z线附近的钙离子浓度在运动后即刻和恢复期的12~72 h呈2次上升趋势,其中EA组第2次上升更早且明显。1次离心运动不能破坏RyR的稳定性。结论:运动后即刻的[Ca2+]i升高介导导了损伤,而运动后12~72 h内的第2次[Ca2+]i升高与组织修复有关,此升高非RyR不稳产生"钙漏"而导致的破坏性"钙超载"。研究价值:本研究发现离心运动过后72 h内不同时间段内,钙离子升高具有截然不同的效应,为肌肉损伤和恢复的钙机制研究提供新的方向。     

Effects of forward trunk lean on hamstring muscle kinematics during sprinting

This study aimed to investigate the effects of forward trunk lean on hamstring muscle kinematics during sprinting. Eight male sprinters performed maximal-effort sprints in two trunk positions: forward lean and upright. A three-dimensional musculoskeletal model was used to compute the musculotendon lengths and velocity of the biceps femoris long head, semitendinosus, and semimembranosus muscles during the sprinting gait cycle. The musculotendon lengths of all the three hamstring muscles at foot strike and toe-off were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. In addition, a positive peak musculotendon lengthening velocity was observed in the biceps femoris long head and semimembranosus muscles during the late stance phase, and musculotendon lengths at that instant were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. The present study provides significant evidence that a potential for hamstring muscle strain injury involving forward trunk lean sprinting would exist during the stance phase. The results also indicate that the biceps femoris long head and semimembranosus muscles are stretched during forward trunk lean sprinting while contracting eccentrically in the late stance phase; thus, the elongation load on these muscles could be increased.     

Impact of age on haematological markers pre- and post-marathon running

This study investigated whether haematological markers differ between young and masters marathon participants, running at similar performance levels. Nine young (31.89 ± 4.96 years) and eight masters (63.13 ± 4.61 years) runners participated. At five time points (pre-race through 54 h post-race), a complete blood cell count, basic metabolic panel and creatine kinase (CK) isoenzyme panel were assessed. Race performance was standardised using the World Masters Association Age Grading Performance Tables. Total CK levels were elevated for all participants at all time points post-race (P < 0.001). The CK-isoenzyme MB% was elevated across groups at 6, 30 and 54 h post-race (P < 0.01, P < 0.01 and P < 0.05), with masters runners having a higher CK-MB% at 30 and 54 h (P < 0.05, P < 0.05). Total white blood cell and neutrophil counts were elevated through 6 h post-race (P < 0.001), with higher levels found in younger runners (P < 0.001). When considering all blood work, masters runners had a higher number of abnormal values at 6, 30 and 54 h post-race (P < 0.05, P < 0.01 and P < 0.05). In conclusion, masters runners demonstrated sustained CK-MB elevation, which may suggest greater cardiac stress. However, future studies using additional cardiac markers should be completed to confirm these findings. In addition, masters runners showed an increased number of laboratory values outside normal range, indicating the body’s reduced capacity to respond to marathon running.     

Temporal specificity of training: intra-day effects on biochemical responses and Olympic-Weightlifting performances

The aim of this study was to investigate the performance of an Olympic-Weightlifting session training at three times of the day on the performance related to biochemical responses. Nine weightlifters (21 ± 0.5 years) performed, in randomised order, on three Olympic-Weightlifting training (snatch, clean and jerk) sessions (08:00 a.m., 02:00 p. m., 06:00 p. m.). Blood samples were collected: before, 3 min and 48 h after each training session. Haematological parameters and markers of muscle injury were assessed. Resting oral temperature and rating of perceived exertion (RPE) were also assessed during each session. ANOVA showed that the performance was better (P < 0.001) at 02:00 p. m. with a less RPE (P < 0.01) compared to the morning and the evening sessions while there was higher (P < 0.05) oral temperature at 06:00 p. m. versus 08:00 a.m. and 02:00 p. m. Muscle damage changed immediately (without significant effect after 48 h) after the training sessions with lower values ??in the evening compared to the morning. In conclusion, the afternoon training is more effective than morning or evening sessions for weightlifters. Therefore, coaches and weightlifters should be advised to schedule their training session in the afternoon hour.     

竞技健美操有氧舞蹈项目第二风格动作编排特征研究

第二风格动作是有氧舞蹈区别于其他竞技健美操项目显著的构成要素,运用文献资料法、录像观察法、数理统计法对第13届健美操世锦赛有氧舞蹈项目决赛8支队伍第二风格动作编排进行研究,结果显示编排特征为:目前第二风格动作出现位置在成套动作的中1/3比较合理;第二风格动作可选择的舞蹈风格广泛,应大胆尝试;内容中多融入大幅度动作和复杂多变的配合,技术技巧和托举动作不适合出现;音乐节奏感强,注重与成套音乐的衔接和配合及音乐风格的吻合或呼应。