Electromyographic analysis of thigh muscles during track cycling on a velodrome

We aimed to investigate neuromuscular activation of thigh muscles during track cycling at various speeds. Eight male competitive cyclists volunteered to participate in this study. Surface electromyography of the vastus lateralis, biceps femoris and adductor magnus muscles of the bilateral legs was recorded during track cycling on velodromes with a 250-m track. The participants were instructed to maintain three different lap times: 20, 18 and 16 s. The average rectified value (ARV) was calculated from the sampled surface electromyography. Significantly higher ARVs were observed in the right compared to left leg for the biceps femoris muscle during both straight and curved sections at 18- and 16-s lap times (P < 0.05). In the biceps femoris muscle, significant changes in ARVs during the recovery phase with an increase in speed were seen in the right leg only (P < 0.05). There were no significant differences in ARVs between the straight and curved sections for all three muscles (P > 0.05). From our findings, it was suggested that during track cycling on a velodrome the laterality of the biceps femoris muscle activity is a key strategy to regulate the speed, and fixed neuromuscular strategies are adopted between straight and curved sections for thigh muscles.     

高师声乐课教学模式改革试探

要提高学生的整体音乐素质，有一个十分重要的环节必须特别加以重视，即应改革音乐教学模式。突出主体性，并利用“微格教学”，拓宽教学内容，这样才能培养出高素质和开拓型的音乐教育人才。     

ISAS课程的引入和推广

本文介绍了信息搜索和分析技能（ISAS）课程的引入情况，简要说明了ISAS课程目的、评分标准，并对引入该课程后的效果进行了评价分析，最后介绍了ISAS课程的推广情况。     

语篇连贯的扩展——互文性与连贯的超语篇认知阐释

连贯是语篇分析的重要课题之一。从互文性角度对连贯现象进行重新审视,一方面,展示出了互文性与连贯的紧密联系,另一方面,更揭示了语篇连贯的实质,即语篇的连贯是与当前语篇相关的主客体在语篇交际中的认知整合性连贯,是超出单个语篇范围、诸因素间的理据性关系。连贯的互文分析法,能给研究语篇连贯提供一个新的视角。     

增程式混合动力集装箱龙门起重机能量智能控制策略

针对集装箱龙门起重机的具体工况需求和特点,构建一种适用于集装箱龙门起重机的增程式混合动力系统,提出并分析该动力系统的能量智能控制策略,设计相应的智能控制模型.通过以动力电池组的荷电状态（State Of Charge, SOC）和集装箱龙门起重机运行能量需求为模糊输入,以动力电池组的充电功率为模糊输出,实现了对增程式混合动力系统的智能控制.仿真结果验证了该控制策略和控制模型的可行性和有效性.     

跆拳道后旋踢技术动作的运动学特征分析

采用三维高速摄像技术和运动生物力学原理,对后旋踢技术身体重心移动、动作所用时间、踝关节角度、膝关节角度和髋关节角度的运动学特征进行比较分析,得出结论:踢击腿在离地瞬间身体重心要快速向回旋方向移动;踢击腿膝关节最大程度弯曲,以缩短动作时间、加快踢击速度;踢击腿髋关节只有最大程度地弯曲,弯曲的膝关节才能快速展开;踢击腿的髋关节最大程度弯曲再打开时,踝关节能快速鞭打;支撑腿弯曲后在踢击腿踢出的瞬间,髋关节开始伸展,将对打击高度产生影响;踢击腿膝关节和髋关节最大程度弯曲时能增加击打力度.     

Sexual dimorphism in bone–muscle relationship in young adults

The purpose of this study was to analyse associations between lean soft tissue (LST), a surrogate of skeletal muscle mass and key fracture-related geometric characteristics of the proximal femur. Moreover, we examined the role that muscle played on the proximal femur geometry in response to physical activity (PA). Participants were 83 young adults. Leg LST (exposure) was assessed by dual energy X-ray absorptiometry (DXA). Proximal femur geometry was derived from a left hip DXA scan. Geometric variables (outcomes) included the femoral neck axis length (FNAL), the femoral neck width (FNW), the neck–shaft angle and FNW|FNAL (an index of robustness). PA was evaluated by accelerometry. Linear regression was used to analyse relationships. Additional exposure variables included body height and mass. In males, leg LST explained 17.4% of variation in FNAL (P < 0.001) and 15% in FNW (P = 0.015). In females, it explained 8.8% of the variance in FNAL (P = 0.020). Associations remained significant in males, but not in females, when vigorous PA was added to the models. These results suggest that public health approaches to promote PA may be particularly important in females since vigorous PA seems to convey advantages in femur geometry and consequently in bone strength.     

街舞运动的文化特征与功能

为了更高层次上理解、认识街舞运动以及挖掘街舞运动社会文化功能，从文化学的角度，探讨了街舞运动所具有的健身性和艺术性、多样性和变异性、国际性和地域性、竞争性和自由性、兼容性和从属性的文化特征，分析了街舞运动在人的社会化、人生命价值观的表意性符号、社会经济发展、实施全民健身战略、构建和谐社会等方面具有的文化功能。     

不同角速度下男子跳远运动员髋关节肌群等速向心收缩的肌力研究

利用Cybex-770等速肌力测试与康复系统,以150°/s、90°/s、60°/s 3种角速度对17名优秀跳远运动员起跳腿髋关节进行等速向心收缩测试.获得了相应的等速向心收缩的相对峰力矩、相对总功、相对平均功率和峰力矩屈伸比的指标,并结合项目特点,力争为跳远训练提供更科学的服务.     

Increasing plantarflexion angle during landing reduces vertical ground reaction forces,loading rates and the hip’s contribution to support moment within participants

The ankle joint’s role in shock absorption during landing has been researched in many studies, which have found that landing with higher amounts of plantarflexion (PF) results in lower peak vertical ground reaction forces and loading rates. However, there has not yet been a study that compares drop landings within participants along a quantitative continuum of PF angles. Using a custom-written real-time feedback program, participants adjusted their ankles to an instructed PF angle and dropped onto two force platforms. For increasing PF, peak ground reaction force and peak loading rate during weight acceptance decreased significantly. The hip’s contribution to peak support moment decreased as PF at initial contact increased up to 30°. The ankle and knee contributions increased over this same continuum of PF angles. There appears to be no optimal PF angle based on peak ground reaction force and loading rate measurements, but there may be an optimum where joint contributions to peak support moment converge and the hip moment’s contribution is minimised.