Reviewing the Variability-Overuse Injury Hypothesis: Does Movement Variability Relate to Landing Injuries?     

Andrew D. Nordin  Janet S. Dufek 《Research quarterly for exercise and sport》2019,90(2):190-205

Purpose: Overuse injuries are common in sport, but complete understanding of injury risk factors remains incomplete. Although biomechanical studies frequently examine musculoskeletal injury mechanisms, human movement variability studies aim to better understand neuromotor functioning, with proposed connections between overuse injury mechanisms and changes in motor variability. Method: In a narrative review, we discuss the variability-overuse injury hypothesis, which suggests repeated load application leads to mechanical tissue breakdown and subsequent injury when exceeding the rate of physiological adaptation. Due to the multidisciplinary nature of this hypothesis, we incorporate concepts from motor control, neurophysiology, biomechanics, as well as research design and data analysis. We therefore summarize multiple perspectives while proposing theoretical relationships between movement variability and lower extremity overuse injuries. Results: Experimental data are presented and summarized from published experiments examining interactions between experimental task demands and movement variability in the context of drop landing movements, along with comparisons to previous movement variability studies. Conclusion: We provide a conceptual framework for sports medicine researchers interested in predicting and preventing sports injuries. Under performance conditions with greater task demands, we predict reduced trial-to-trial movement variability that could increase the likelihood of overuse injuries.  相似文献   

竞技太极拳中32系列难度动作单脚支撑落地稳定性训练探析     

易鹏  王飞  夏成才  于君玲 《武汉体育学院学报》2019,53(8):76-81

基于运动人体科学与运动训练学的相关理论，采用文献分析法、参与观察法、专家访谈法、问卷调查法等研究方法，对竞技太极拳中32系列难度动作落地单脚支撑技术特征进行理论分析和规律探讨。旨在从整体上系统地理解竞技太极拳中32系列难度动作各阶段间的关系，进而准确把握此类动作训练方法设计的理论基础，从而设计科学合理的训练方法，以提高运动员32系列难度动作落地单脚支撑的稳定性。研究得出，可通过SWISS球上俯卧转体等训练提高核心肌群的协调控制能力，BOSU球上单双腿直立或半蹲等练习增强髋关节肌群的离心收缩能力和协调控制能力，仰卧屈膝足跟夹SWISS球、手法松解等方式增强膝关节不同肌群的等长收缩、向心收缩、神经协调控制能力；通过踝关节PNF拉伸、跖趾关节PNF拉伸等增强足底非固有肌离心收缩能力和柔韧性，提高足底固有肌的神经协调能力。  相似文献   

半主动控制起落架实验系统   总被引：1，自引：0，他引：1  

贾玉红  吴永康  张冠超 《实验室研究与探索》2006,25(2):173-175

介绍了半主动控制起落架实验系统的组成,提出了半主动控制的实验方案,并对振动模块、结构模块、数据采集模块和控制模块进行了分析。在建立起落架减振系统力学模型的基础上,提出了提高起落架性能的半主动控制的控制律。本实验系统具有综合性、通用性和先进性的特点。  相似文献   

关于田径教材中跑步技术原理某些理论问题的探讨     

张明俊 《许昌学院学报》2004,23(5):128-131

对于跑步技术提出了新的观点：基于两腿周期动作同时具有对应性、同步性和反方向性的特征，把单腿动作周期划分为折叠后摆、前摆、下压着地缓冲、后蹬四个阶段，有利于双腿动作协调配合的动力学特征分析．  相似文献   

基于复杂网络和粒子群算法的滤波与轨道优化模型     

杨凌  许铭 《丽水学院学报》2015,(2):14-21

嫦娥三号已成功完成软着陆,其着陆准备轨道的位置和着陆轨道及其控制策略是嫦娥三号月球着陆的关键问题。运用天体物理相关理论及智能优化算法构建了基于复杂网络的滤波模型和基于粒子群算法的着陆轨道优化模型,并通过matlab计算及matlab仿真,给出了着陆轨道及其控制策略。  相似文献   

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

K. Michael Rowley  James G. Richards 《Journal of sports sciences》2015,33(18):1922-1931

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.  相似文献   

应用非线性规划求解月球探测器着陆轨道最优控制     

肖刚 《韩山师范学院学报》2015,(3)

为了减少有限推力作用下月球探测器软着陆所需的燃料消耗,提出了应用非线性规划方法来求解该最优控制问题。首先,将有限推力作用下月球软着陆问题转化为数学上的两点边值问题;在考虑边界条件的前提下,利用拉格朗日原理将该两点边值问题转化为针对控制变量的优化问题;然后应用非线性规划方法求解所形成的参数优化问题。实验仿真结果显示,该方法能够成功实现月面软着陆,表明提出的设计方法简单有效。  相似文献   

Blocking landing techniques in volleyball and the possible association with anterior cruciate ligament injury     

David Zahradnik  Daniel Jandacka  Michal Holcapek  Roman Farana  Jaroslav Uchytil  Joseph Hamill 《Journal of sports sciences》2018,36(8):955-961

The number and type of landings performed after blocking during volleyball matches has been related to the potential risk of ACL injury. The aim of the present study was to determine whether gender affects the frequency of specific blocking landing techniques with potential risk of ACL injury from the perspective of foot contact and subsequent movement after the block used by volleyball players during competitive matches. Three matches involving four female volleyball teams (fourteen sets) and three matches involving four male volleyball teams (thirteen sets) in the Czech Republic were analyzed for this study. A Pearson chi-square test of independence was used to detect the relationship between gender and different blocking techniques. The results of the present study showed that gender affected single-leg landings with subsequent movement in lateral direction and double-leg landings. Although the total number of landings was lower for male athletes than for female athletes, a larger portion of male athletes demonstrated single leg landings with a subsequent movement than female athletes. Single leg landings with a subsequent movement have a higher potential risk of ACL injury.  相似文献   

2019年夏季全国气候趋势展望          下载免费PDF全文

彭京备  布和朝鲁  郑飞  陈红  郎咸梅  詹艳玲  林朝晖  张庆云  林壬萍  李超凡  马洁华  田宝强  包庆  穆松宁  陆日宇  朱江 《中国科学院院刊》2019,34(6):693-699

2019年春夏季，赤道中东太平洋将维持弱-中等强度厄尔尼诺（El Niño）。中国科学院大气物理研究所的全国气候趋势预测结果表明，预计2019年汛期（6—8月），长江中下游以南大部分地区降水偏多，其中江南地区偏多2—5成，可能发生局地洪涝灾害；新疆北部、东北北部、四川东部和陕西南部等地降水正常略偏多。我国其他大部分地区降水正常略偏少，其中河套地区降水偏少2—5成。预计2019年登陆台风数正常略偏多。  相似文献   

基层电大开放教育接轨农村、服务农民的和谐理念     

严晓琴  吴国富 《南京广播电视大学学报》2006,(1):25-28

致力于中国农民素质教育是电大系统实施网络教育必须担负的历史使命,基层电大接轨农村、服务农民是开放教育可持续发展的必然趋势。当今农村地区发展的不平衡现状和农民个体活动呈现的独立性、选择性、多变性等形态,决定了各地基层电大在向农村和农民实施开放教育的过程中,必须于教育观念、教育技术以及教育中远期目标上紧紧把持和谐的理念。  相似文献