【作者】 钟运健；

【导师】 刘宇；

【作者基本信息】 上海体育学院 ， 运动人体科学， 2010， 博士

【摘要】 研究目的：利用环节互动动力学方法计算快速跑时下肢各关节肌力矩、惯性力矩、外力矩、重力矩,并量化各关节角度变化和下肢各肌群功率,以提升快速跑时下肢各关节动力学的理解；量化快速跑时下肢单块肌肉长度变化和速度变化,探讨快速跑时最优化算法中反映快速跑时人体神经肌肉系统最优控制的目标函数和算法,以静态最优化算法估算出肌肉力量(应力),并进一步量化单块肌肉单位面积功率及做功总和,结合快速跑完整步态中下肢各单块肌肉工作性质,尤其是运动过程中极易受伤的胭绳肌的工作状态及其在跑速中所扮演的角色以综合探讨其损伤机理及发生时相。研究方法：采集8名优秀短跑运动员在塑胶跑道上途中跑时完整步态的二维运动学数据(300 Hz)及与之同步的地面反作用力(1200Hz)数据和肌电图(1200Hz),利用环节互动动力学方法分析下肢各关节力矩,并量化各关节角度变化和下肢各关节肌群功率变化。基于受测对象个体的下肢骨性形态学参数和快速跑时下肢运动学二维参数,通过下肢肌肉功能模型计算机应用分析系统分别计算出受测对象快速跑时下肢主要肌肉长度变化、速度变化及对于各关节各伪力臂变化。建立简化下肢骨骼-肌肉二维模型,确立目标函数和约束方程,应用中尺度序列二次规划拟牛顿线性搜索算法将快速跑时关节肌力矩优化求解单块肌肉应力,并进一步计算肌肉单位面积功率和单位面积做功总量。研究结果：在支撑阶段,关节力矩起主要控制作用的为肌力矩和外力矩,肌力矩的主要作用为对抗地面反作用力矩。同时,从近端到远端关节依次出现角速度峰值和伸肌的正功率峰值；踝关节角速度峰值和肌肉功率峰值明显高于其它关节的角速度峰值和肌肉功率峰值,而膝关节肌群在整个支撑期功率远低于髋关节和踝关节肌群功率值。摆动阶段,关节力矩主要为肌力矩和惯性力矩,肌力矩则主要对抗惯性力矩做负功以控制动作。在快速跑完整步态中,髋关节伸肌群、膝关节屈肌群及踝关节跖屈群功率峰值均分别显著高于髋关节屈肌群、膝关节伸肌群及踝关节背屈肌群功率峰值,同时,髋关节伸肌群和膝关节屈肌做正功时功率峰值均显著高于其做负功时功率峰值,踝关节跖屈肌群做负功时功率峰值显著高于其做正功时功率峰值；双关节肌胭绳肌、股直肌和腓肠肌应力峰值、长度峰值、收缩速度峰值和做负功单位面积功率峰值均显著高于其他下肢骨骼肌；各肌肉均不同程度地作为拮抗肌在离心收缩且输出较大功率(做负功)对抗外力矩或惯性力矩。快速跑时不少双关节肌在同一时刻分别对两个关节做负功和正功；在摆动期中间阶段,胭绳肌在顺应性离心收缩时突然被激活并快速出现做负功功率峰值；摆动末期,出现胭绳肌长度、速度、应力峰值；触地瞬间,胭绳肌应力和单位面积功率快速增长至支撑期峰值；股二头肌长头的应力峰值、长度峰值、做负功的功率峰值和做负功的总和均显著高于半膜肌和半腱肌。研究结论：快速跑时,作用于身体各环节的外力和惯性力(还包括科氏力和离心力)对各关节肌群工作性质产生重要影响；髋关节伸肌群和膝关节屈肌群的快速主动收缩能力和踝关节跖屈肌群的退让性快速收缩能力在快速跑时极其重要；短跑的专项训练中,应充分重视下肢各相关肌群的在离心收缩情况下的做功能力；应挖掘与短跑时下肢肌肉复杂的工作特点相类似的下肢整体运动(多关节)的训练方法；下肢双关节肌为快速跑时最易受伤的肌肉；摆动期中间阶段、摆动末期及触动地瞬间为快速跑时易发生胭绳肌拉伤的时相；股二头肌长头是胭绳肌群最易拉伤的肌肉。更多还原

【Abstract】 Research objectives:To work out lower-limb joints’muscle torque, inertial torque, contact torque and gravitational torque by using the method of intersegmental dynamics, and to quantify every joint’s angular variation and lower-limb muscles’ power, so as to promote the understanding of lower-limb joints dynamics in sprint running; To quantify lower-limb single muscle’s length and speed variations in sprint running, and to study the objective function and arithmetic of optimization that reflect human body’s optimal control of neuromuscular system in sprint running; To estimate muscle stress by using the method of static optimization, thus to further quantify every single muscle’s unit power and power sum; To study the damage mechanism and time phase of easily-strained hamstring by analyzing every lower-limb muscle’s working feature in the integral gait of sprint running, especially hamstring’s working state and its role in sprint running.Research methods:Eight excellent sprinters’two-dimensional kinetic data (300 Hz) and the data of the ground’s counterforce (1200Hz) are collected in integral gait in their maximum velocity sprint running on a synthetic surface track. In addition, this research applies the approach of intersegmental dynamics to analyze the torque of every lower-limb joint, and to work out the variations of joints angle and muscles power. Based on every examinee’s lower-limb skeletal morphological parameter and his two-dimensional kinetic parameter in sprint running, this research tries to work out respectively length and speed variations of lower-limb major muscles and tension arm variation of every joint by utilizing the method of computer analyzing system of the muscular function model of human lower extremity. In addition, this research also builds a two-dimensional lower-limb musculoskeletal model, establishes objective function and constraint equation, and applies mesoscale sequential quadratic programming pseudo-newton for linear search algorithm to optimize muscle’s torque, thereby working out single muscle’s stress, and further works out muscle unit power and its total power.Research results:During the support phase it is muscle torque and contact torque that take control, and the main function of muscle torque is to withstand contact torque. Meanwhile the peak value of angular velocity and that of the extensor muscle’s positive power emerge in turn from proximal end to distal end. During that phase the ankle’s peak values of angular velocity and muscle power are obviously higher than those of other joints, while the power of knee muscles is much lower than that of hip and ankle muscles. During the swing phase the main joint torques are muscle torque and inertial torque, and muscle torque controls action by acting negatively on inertial torque. In the complete gait of sprint running the peak values of the powers of hip extensor muscles, knee flexor muscles and ankle plantar flexion muscles are apparently higher than those of hip flexor muscles, knee extensor muscles and ankle dorsiflexion muscles. And in the mean time when hip extensor muscles and knee flexor muscles are doing positive work, their peak values of powers are evidently higher than the time when they are doing negative work, and when ankle plantar flexion muscles are doing negative work its peak value of power is obviously higher than the time when they are doing positive work. During every phase the stress value of such two-joint muscles as HAM, RF and GAS is higher than that of the other muscles that do work, and in the integral gait their peak value of stress and the negative work they accumulate in a single gait(the per unit negative work in a single gait) are higher than those of the other muscles. As a kind of antagonistic muscle, every muscle, to some extend, fights against contact torque and inertial torque when it contracts eccentrically and does negative work. In sprint running, some joint muscles do positive work and negative work to two joints at the same time. In the middle phase of swing, hamstring will be triggered abruptly in its compliance eccentric contraction and its peak value of power of negative work emerges immediately. In the telophase of swing peak values of hamstring’s length, speed and stress appears. At the moment of touching the ground hamstring’s stress and per unit power increase quickly to the peak values in support phase, and the peak values of biceps femoris’stress, length and power of doing negative work and sum of negative work are obviously higher than those of semimembranosus and semitendinosusResearch conclusions:In sprint running, external and inertia forces acting on joints of human body (including Coriolis force and centrifugal force) greatly influence the working nature of joint muscles. In the support phase, an outstanding runner can successfully transfer energy to ankle joints, that is, from proximal end to remote end, which strengthens its power on the ground, thus to keep his running speed in a better way. The main function of knee joints is to keep the height of gravity center and deliver energy from hip joint to ankle joint. In sprint running, it is very important of the active swift contractility of hip extensor muscles and knee flexor muscles, and of ankle plantar flexion muscles’passive swift contractility. For that reason, in the specialized training of sprint running, great importance should be attached to lower-limb muscles’ ability of doing work under the circumstances of eccentric contraction. Meanwhile, trainers should try to find out a new training method that is similar to the complicated working feature of lower-limb muscles in sprint running. The research also finds out that lower-limb two-joint muscles are most easily strained in sprint running, that in sprint running hamstring is easily strained in the middle phase and telophase of swing and at the moment of touching the ground, and that long head of biceps femoris muscle is the most easily strained muscle in hamstring muscles.更多还原