太极拳上步弓步动作足前进角对膝关节载荷的影响及肌肉协调收缩策略

目的考察太极拳运动姿势对膝关节载荷的影响及肌肉协调收缩策略。方法募集20名具有3年以上健康太极拳习练者,借助红外高速运动捕捉系统和三维测力台,采集太极拳上步弓步动作支撑腿内收角、胫骨角、关节力、关节力矩等参数,通过仿真方法获取股四头肌和腓肠肌肌肉力。比较惯用步、外展步和内收步肌肉力表现、募集模式和激活方式特征。结果外展步胫骨角和内收力增大,而内收步不变;外展步股内肌、半膜半腱肌及外侧腓肠肌力增大;内收步股外肌和内侧腓肠肌力增强,腓肠肌比股四头肌被优先激活,肌群募集方式发生改变。结论太极拳运动姿势改变肌肉力募集方式,影响膝关节功能,规范动作可作为骨性关节炎运动疗法借鉴,具有临床应用意义。     

基于AnyBody仿真的太极拳不同步型特征

目的 对比太极拳初学者和专业者不同步型的下肢运动学、动力学、肌肉力参数差异,为太极拳科学化及制定运动处方提供依据。方法 以练习时长超过3年的30名太极拳练习者为专业组,30名无太极拳经历初学者作为对照组。用BTS红外捕捉系统、Kistler三维测力台采集太极拳动作数据,以AnyBody 7.0建模仿真系统计算运动学、动力学、肌力参数。结果 专业组独立步膝关节屈伸角度、膝关节X轴受力明显大于对照组（P＜0.01）。弓步、虚步、开立步、马步、仆步、独立步中,专业组下肢肌力均为大于对照组。专业组马步半膜肌、半腱肌、股二头肌肌力大于对照组（P＜0.05）,专业组仆步臀大肌、臀中肌、臀小肌、阔筋膜张肌、股外侧肌、股二头肌肌力大于对照组（P＜0.05）,独立步股外侧肌、股内侧肌、股二头肌、胫骨前肌肌力大于对照组（P＜0.05）。结论 太极拳练习时,膝关节为主要发力关节,专业者下肢用力明显大于初学者。独立步对髋关节影响较大,弓步、仆步对膝关节影响较大。不同水平太极拳练习者对下肢肌肉的激活程度不同,初学者练习时要针对不同动作影响刺激的肌肉,有针对性地区分练习,进而促进下肢肌肉协同用力。     

亚洲蹲和西方蹲的下肢关节运动学和肌肉激活比较

目的分析比较亚洲蹲和西方蹲动作中下肢关节运动学和肌肉激活程度的差异。方法以11名健康成年人为研究对象,采用三维运动捕捉系统、测力台和表面肌电同步采集两种下蹲动作的运动学、动力学和肌肉激活信息,并通过OpenSim计算下肢肌力。结果在膝关节弯曲角度峰值时刻,亚洲蹲骨盆前倾,而西方蹲骨盆后倾;此外,与亚洲蹲相比,西方蹲具有显著较小的髋关节屈角、较大的膝关节屈角、较大的髋关节外展角和内旋角。在自重深蹲的下降期和上升期中,西方蹲的比目鱼肌力峰值均显著大于亚洲蹲,西方蹲的胫骨前肌力均显著小于亚洲蹲,峰值时刻未见统计学差异。结论在亚洲蹲中,胫骨前肌激活和近侧端关节前屈可能有利于稳定;而在脚跟抬起的西方蹲中,比目鱼肌激活显著,但两者近端肌肉激活模式相同。研究结果为临床深蹲康复方案制定或深蹲训练方式的选择提供理论指导。     

冲击载荷作用下运动员下肢动态响应的逆向动力学仿真

目的分析冲击载荷作用下羽毛球运动员下肢关节肌肉的动态响应变化。方法基于Any Body Modeling System软件建立人体肌骨模型,采用实测表面肌电信号进行验证,以运动捕捉系统和测力台测量数据进行模型驱动,对羽毛球右前场蹬跨步上网过程中下肢肌肉肌力、关节力和关节力矩进行逆向动力学仿真与分析。结果所建人体下肢肌骨模型经肌电信号验证有效。羽毛球蹬跨步上网过程中,髋、踝关节Z方向内力峰值显著高于X和Y方向内力峰值,而膝关节X方向内力峰值显著高于Y和Z方向内力峰值;缓冲期,髋关节X、Y、Z方向依次表现为内收力矩、伸髋力矩和内旋力矩,膝关节X、Y、Z方向依次表现为外展力矩、屈膝力矩、外旋力矩,踝关节X、Y方向依次表现为内翻力矩、跖屈力矩,且髋、膝、踝关节X方向力矩峰值显著高于Y和Z方向;股外侧肌、股二头肌、胫骨前肌、腓肠肌内侧在对抗地面冲击载荷时的肌力发挥较大,股直肌、半膜肌、比目鱼肌发挥的作用相对较小。结论建立的下肢肌骨模型可为冲击载荷作用下运动员下肢生物力学特性分析提供技术平台。为避免运动损伤,类似羽毛球前场蹬跨步上网冲击动作中尤其要重视触地瞬间地面反作用力载荷对髋、膝、踝关节前后及内外侧方向生物力学性质的影响,同时在对羽毛球运动员进行专项训练时切勿忽视对股外侧肌、股二头肌、胫骨前肌的专项力量发展。     

脑卒中患者步态启动时早期姿势调节阶段时间和强度参数特点

背景：早期姿势调节为即将执行的动作或面临的姿势干扰做出准备，从而有助于更好地执行动作以及减少干扰对姿势造成的不稳定影响。目的：探索不同平衡能力的脑卒中患者在以舒适速度启动步行时下肢关键肌在早期姿势调节阶段的时间和强度参数特点。方法：观察16例脑卒中恢复期患者早期姿势调节特点，根据有无跌倒史及Berg平衡量表得分分为无跌倒组8例和跌倒组8例。使用Noraxon惯性传感器、Noraxon Ultium EMG无线表面肌电仪采集步态启动过程中患者身体运动学数据和表面肌电数据。分析早期姿势调节阶段下肢胫骨前肌、腓肠肌内外侧、股直肌、股外侧肌和股二头肌6块关键肌的肌肉激活时间和激活顺序，以及步态启动前4个时间窗(各150 ms)的标准化的肌电积分值。结果与结论：(1)有跌倒史的患者在步态启动时，下肢6块关键肌的肌肉激活时间均早于无跌倒组，胫骨前肌、腓肠肌外侧头和股外侧肌的激活时间显著早于无跌倒组(P <0.01,P <0.05)；无跌倒组的肌肉激活顺序呈现出了比较规律的先激活伸肌后激活屈肌、大腿部肌肉激活早于小腿肌肉激活的特点；而跌倒组小腿部伸肌的激活要早于大腿部伸肌的激活，股外侧肌...     

两种不同肌肉力求解算法的对比分析

目的 探究静态优化(static optimization, SO)算法和计算肌肉控制(computed muscle control, CMC)算法求解肌肉力结果的异同,为研究人员选择合适的肌肉力求解算法和横向对比不同研究的结果提供依据。方法 以4种不同速度下跑步的步态作为研究动作,分别利用SO和CMC算法求解单个步态周期中下肢主要肌肉的肌肉力和肌肉激活,并进行对比分析。结果 在参与跑步的10块主要肌肉中,除了胫骨前肌和股直肌外,两种算法求解的肌肉力和肌肉激活具有相似的变化曲线,且相关系数均在0.91以上,但SO算法求解的肌肉力峰值偏高,肌肉激活峰值的位置约有10 ms延迟。结论 在动作分析时,如果研究重点在肌肉发力的时序以及不同肌肉之间的贡献比时,两种算法的选择没有太大区别,建议选择简单高效的SO算法。在横向对比不同研究中SO和CMC算法求解的肌肉力和肌肉激活结果时,需要考虑两者的差异。     

搂膝拗步膝踝关节预激活与共收缩的表面肌电分析

目的 分析长期太极拳练习者进行搂膝拗步和正常行走时下肢膝、踝关节肌群预激活与共收缩的表面肌电（surface electromyography, sEMG）特征,探讨太极预防跌倒的神经肌肉控制策略。方法 采用Vicon运动捕捉系统、Kistler测力板和Noraxon表面肌电图系统同步采集搂膝拗步和正常行走时股直肌、股二头肌、胫骨前肌、外侧腓肠肌的sEMG信号和体位信息。通过股直肌和股二头肌、胫骨前肌和外侧腓肠肌两对肌肉的积分肌电分别计算膝、踝关节预激活和共收缩。结果 与正常行走相比,搂膝拗步在4个阶段的平均用时显著增加;搂膝拗步在4个阶段内时间百分比存在显著性差异;搂膝拗步膝关节共收缩水平和预激活水平降低,踝关节共收缩水平和预激活水平升高。结论 长期的太极拳练习可能使膝关节周围肌肉的激活水平提高,增强肌肉群之间的协同作用,以帮助稳定关节。研究结果为神经肌肉控制障碍疾病的康复评估和训练提供参考。     

痉挛型脑瘫儿童手术后表面肌电信号和关节角度评估

目的 通过表面肌电(surface electromyography, sEMG)和关节角度评估脑瘫儿童手术后运动功能。方法 采集16名痉挛型脑瘫患儿手术前后直线行走时股直肌、股二头肌、半腱肌、胫骨前肌、腓肠肌内外侧sEMG和髋、膝、踝关节角度,计算各步态时期sEMG均方根、积分肌电值和关节角度均值,进行肌力肌张力评估。结果 手术后,患儿下肢肌肉肌张力均显著降低(P<0.05),股直肌和股二头肌在摆动阶段肌力减小。胫骨前肌在摆动中末期肌力增大(P<0.05)。髋、膝关节屈曲角降低(P<0.05)。踝关节背屈角增大(P<0.05),内翻角减小(P<0.05)。结论 治疗后患者蹲伏步态和马蹄内翻足均得到改善,运动功能得到提升。sEMG结合关节角度分析可对患者肌肉功能进行定量评估,为临床诊断提供参考。     

太极拳白鹤亮翅对下肢肌电活动的影响

目的通过对比太极拳初学者和太极拳运动员白鹤亮翅动作关节角度活动变化、压力中心(center of pres-sure,COP)变化和肌肉活动特点,分析运动员是如何通过肌肉活动控制其白鹤亮翅的姿势平衡。方法太极拳运动员和初学者分两组各10人。记录太极白鹤亮翅动作时双下肢10块骨骼肌表面肌电图、双下肢3大关节的二维角运动和COP在侧方和前后的移位。每次试验8 s完成,重复5次。统计处理后,做肌电运动和平衡分析;其中肌电数据做标准化处理,并比较太极拳运动员和初学者的异同。结果运动员组支撑腿胫骨前肌、股二头肌、臀中肌)的肌电活动表现为显著高于初学者同侧腿骨骼肌的肌电活动;运动员组虚步腿的腓肠肌和股直肌的肌电活动显著高于初学组同侧同名肌。运动员组下肢3大关节最大平均活动角度比初学组大,支撑腿髋关节显著高于初学组同侧同关节。运动员组COP前后方向位移显著小于初学组。结论运动员可以通过肌肉活动的增强对抗COP的移位,保持姿势平衡稳定,而初学者COP前后移位失控时并没表现出积极的肌肉活动。初步解释了太极拳练习能提高人体下肢肌肉力量和平衡控制能力的原因。     

基于AnyBody仿真和肌电测试分析不同体质量指数男性青年球类运动中的生物力学特征

文题释义： Anybody仿真：使用数学建模技术模拟人体肌肉骨骼在不同载荷中的情况,计算各块肌肉和关节的受力、变形、肌腱的弹性能、拮抗肌肉运动和其他对于工作中的人体有用的特性,以计量方式计算出人体对于环境的反应,兼与人机工程学和生物力学分析,为人体运动建模、人机工程学产品性能改进和生物医学工程研究提供平台。 均方根振幅：是将振幅平方的平均值开平方,把振幅值平均然后开方,最原始的是针对正弦波推导出来的,但实际上对所有的波形都适用,均方根值(RMS)也称作为效值,表示在一段周期内,参加肌肉活动的肌肉瞬间肌电图振幅均方根值,是一定时间内肌电位值平方和的平方根。 背景：Anybody肌肉骨骼建模系统,使用数学建模技术模拟人体骨骼、肌肉和环境的关系,可对人体的逆向动力学进行研究,得出下肢三关节最大肌肉力等指标。 目的：研究24名不同体质量指数男大学生在坐瑞士球一个动作周期的下肢肌肉力值,及受试者在坐瑞士球与平凳的均方根肌电平均值对比情况。 方法：将24名男大学生按体质量指数分为正常组、超重组、肥胖组,用BTS三维红外动作捕捉系统、Kistler 三维测力台、BTS表面肌电测试系统,同步记录动力学和肌电参数,以单因素方差分析定性比较不同组间肌力和肌电参数差异,用定量差异分析法对比均值差异。 结果与结论：①肌肉力量方面,由坐到站过程中,正常组与肥胖组相比,股直肌、半膜肌、股二头肌长头、腘肌、比目鱼肌、胫骨前肌差异显著(P < 0.05,0.47≤QD<0.80),股方肌与耻骨肌的两组肌肉力差异极其显著(P < 0.01,QD≥0.80);超重组与肥胖组肌肉力相比,股方肌具有显著性差异(P < 0.05,0.47≤QD<0.80),由站到坐过程中,正常组与肥胖组相比,缝匠肌、拇长伸肌、腓肠肌肌肉力差异显著(P < 0.05,0.47≤QD<0.80);②均方根肌电值方面,坐平凳状态下,由坐到站过程中,正常组与肥胖组相比,股二头肌和腓肠肌差异显著(P < 0.05,0.47≤QD<0.80),由站到坐过程中,正常组与肥胖组相比,股直肌差异显著(P < 0.05,0.47≤QD<0.80);坐瑞士球状态下,由坐到站过程中,正常组与肥胖组相比,胫骨前肌、股二头肌差异显著(P < 0.05,0.47≤QD<0.80);由站到坐过程中,正常组与肥胖组相比,腓肠肌、右竖脊肌肌电值差异显著(P < 0.05,0.47≤QD<0.80)。提示：①各组由坐到站过程中主导发力肌肉是臀中肌、股外侧肌、股二头肌长头、股直肌、腓肠肌、胫骨前肌、比目鱼肌,由站到坐过程中下肢臀中肌、股外侧肌和股二头肌长头、腓肠肌、胫骨前肌、比目鱼肌主导发力;②与坐平凳相比,受试者在坐瑞士球时胫骨前肌、股直肌、股二头肌、腓肠肌均方根肌电值高。ORCID: 0000-0003-0520-5606(庞博) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Length and moment arm of human leg muscles as a function of knee and hip-joint angles

Summary Lengths of muscle tendon complexes of the quadriceps femoris muscle and some of its heads, biceps femoris and gastrocnemius muscles, were measured for six limbs of human cadavers as a function of knee and hip-joint angles. Length-angle curves were fitted using second degree polynomials. Using these polynomials the relationships between knee and hip-joint angles and moment arms were calculated. The effect of changing the hip angle on the biceps femoris muscle length is much larger than that of changing the knee angle. For the rectus femoris muscle the reverse was found. The moment arm of the biceps femoris muscle was found to remain constant throughout the whole range of knee flexion as was the case for the medial part of the vastus medialis muscle. Changes in the length of the lateral part of the vastus medialis muscle as well as the medial part of the vastus lateralis muscle are very similar to those of vastus intermedius muscle to which they are adjacent, while those changes in the length of the medial part of the vastus medialis muscle and the lateral part of the vastus lateralis muscle, which are similar to each other, differ substantially from those of the vastus intermedius muscle. Application of the results to jumping showed that bi-articular rectus femoris and biceps femoris muscles, which are antagonists, both contract eccentrically early in the push off phase and concentrically in last part of this phase.     

Atlas of the muscle motor points for the lower limb: implications for electrical stimulation procedures and electrode positioning

The aim of the study was to investigate the uniformity of the muscle motor point location for lower limb muscles in healthy subjects. Fifty-three subjects of both genders (age range: 18–50 years) were recruited. The muscle motor points were identified for the following ten muscles of the lower limb (dominant side): vastus medialis, rectus femoris, and vastus lateralis of the quadriceps femoris, biceps femoris, semitendinosus, and semimembranosus of the hamstring muscles, tibialis anterior, peroneus longus, lateral and medial gastrocnemius. The muscle motor point was identified by scanning the skin surface with a stimulation pen electrode and corresponded to the location of the skin area above the muscle in which an electrical pulse evoked a muscle twitch with the least injected current. For each investigated muscle, 0.15 ms square pulses were delivered through the pen electrode at low current amplitude (<10 mA) and frequency (2 Hz). 16 motor points were identified in the 10 investigated muscles of almost all subjects: 3 motor points for the vastus lateralis, 2 motor points for rectus femoris, vastus medialis, biceps femoris, and tibialis anterior, 1 motor point for the remaining muscles. An important inter-individual variability was observed for the position of the following 4 out of 16 motor points: vastus lateralis (proximal), biceps femoris (short head), semimembranosus, and medial gastrocnemius. Possible implications for electrical stimulation procedures and electrode positioning different from those commonly applied for thigh and leg muscles are discussed.     

Synchronization of lower limb motor unit activity during walking in human subjects

Synchronization of motor unit activity was investigated during treadmill walking (speed: 3-4 km/h) in 25 healthy human subjects. Recordings were made by pairs of wire electrodes inserted into the tibialis anterior (TA) muscle and by pairs of surface electrodes placed over this muscle and a number of other lower limb muscles (soleus, gastrocnemius lateralis, gastrocnemius medialis, biceps femoris, vastus lateralis, and vastus medialis). Short-lasting synchronization (average duration: 9.6 +/- 1.1 ms) was observed between spike trains generated from multiunit electromyographic (EMG) signals recorded by the wire electrodes in TA in eight of nine subjects. Synchronization with a slightly longer duration (12.8 +/- 1.2 ms) was also found in 13 of 14 subjects for paired TA surface EMG recordings. The duration and size of this synchronization was within the same range as that observed during tonic dorsiflexion in sitting subjects. There was no relationship between the amount of synchronization and the speed of walking. Synchronization was also observed for pairs of surface EMG recordings from different ankle plantarflexors (soleus, medial gastrocnemius, and lateral gastrocnemius) and knee extensors (vastus lateralis and medialis of quadriceps), but not or rarely for paired recordings from ankle and knee muscles. The data demonstrate that human motor units within a muscle as well as synergistic muscles acting on the same joint receive a common synaptic drive during human gait. It is speculated that the common drive responsible for the motor unit synchronization during gait may be similar to that responsible for short-term synchronization during tonic voluntary contraction.     

不同负荷运动中下肢肌表面肌电图的变化

背景：尝试应用曲线拟合分析方法对表面肌电图进行分析和研究国内外尚处于起步阶段,将其应用于功率自行车运动至疲劳的研究鲜见报道。 目的：探讨功率自行车不同负荷运动中下肢肌中值频率值的变化特征和规律,分析肌肉疲劳拟合曲线的特点及其影响肌肉疲劳的相关因素。 方法：受试者为苏州大学体育学院8名男性青年,利用MONARK功率自行车,对受试者在不同负荷以及不同踏蹬频率下进行测试至疲劳,同时对股直肌、股外侧肌、股内侧肌、胫骨前肌、腓肠肌内侧头和腓肠肌外侧头进行表面肌电信号的采集与记录。分析中值频率指标的变化,并用minitab.15统计软件,按照在F检验的统计学差异有非常显著性意义(P < 0.001)的前提下,选取判定系数R2最大,偏差的平方和最小的原则,对实验结果进行曲线优度拟合。 结果与结论：①功率自行车150 W运动时,肌纤维的募集形式由运动初始快肌纤维募集数量逐渐增多向慢肌纤维募集比例增高转变。②功率自行车300 W运动时,肌纤维的募集形式从运动初期的快肌纤维募集为主逐渐向慢肌纤维募集比例增高转变。③功率自行车150 W运动时,肌肉疲劳的拟合曲线均为三次项曲线,提示影响肌肉疲劳的主要因素有3个。300 W运动时,肌肉疲劳的拟合曲线均为二次项曲线,提示影响肌肉疲劳的主要因素有2个。     

A comparison of the moment arms of pelvic limb muscles in horses bred for acceleration (Quarter Horse) and endurance (Arab)

Selective breeding for performance has resulted in distinct breeds of horse, such as the Quarter Horse (bred for acceleration) and the Arab (bred for endurance). Rapid acceleration, seen during Quarter Horse racing, requires fast powerful muscular contraction and the generation of large joint torques, particularly by the hind limb muscles. This study compared hind limb moment arm lengths in the Quarter Horse and Arab. We hypothesized that Quarter Horse hind limb extensor muscles would have longer moment arms when compared to the Arab, conferring a greater potential for torque generation at the hip, stifle and tarsus during limb extension. Six Quarter Horse and six Arab hind limbs were dissected to determine muscle moment arm lengths for the following muscles: gluteus medius, biceps femoris, semitendinosus, vastus lateralis, gastrocnemius (medialis and lateralis) and tibialis cranialis. The moment arms of biceps femoris (acting at the hip) and gastrocnemius lateralis (acting at the stifle) were significantly longer in the Quarter Horse, although the length of the remaining muscle moment arms were similar in both breeds of horse. All the Quarter Horse muscles were capable of generating greater muscle moments owing to their greater physiological cross-sectional area (PCSA) and therefore greater isometric force potential, which suggests that PCSA is a better determinant of muscle torque than moment arm length in these two breeds of horse. With the exception of gastrocnemius and tibialis cranialis, the observed muscle fascicle length to moment arm ratio (MFL : MA ratio) was greater for the Arab horse muscles. It appears that the Arab muscles have the potential to operate at slower velocities of contraction and hence generate greater force outputs when compared to the Quarter Horse muscles working over a similar range of joint motion; this would indicate that Arab hind limb muscles are optimized to function at maximum economy rather than maximum power output.     

Theoretical determination of force-length relations of intact human skeletal muscles using the cross-bridge model

The purpose of this study was to determine force-length relations of selected human skeletal muscles, based on the theoretical foundations of the cross-bridge model and to calculate a strength curve for knee extension from these relations. Force-length relations were determined for the rectus femoris, vastus lateralis, vastus medialis, vastus intermedius and gastrocnemius muscles, using sarcomere/ fiber length data form both legs of four cadavers and sarcomere geometry data reported in the literature. It appears that the two-joint muscles investigated in this study are not able to produce force throughout their full anatomical range of motion, whereas the one-joint muscles can. The strength curve for knee extension was determined as the sum of the force-length relations of the individual knee extensor muscles and showed good agreement with experimentally obtained knee extensor strength curves.     

Characteristic of Changes in the Structure and Metabolism of the Vastus Lateralis Muscles in Monkeys after Space Flight

Monkeys subjected to space flight were found to have significant decreases in the sizes of slow and rapid fibers in the vastus lateralis muscle, due not only to weightlessness but also, to some extent, to restriction of movement activity within the capsule. The quantity of total protein in muscle fibers did not decrease. The respiratory peak in the pool of vastus lateralis muscle fibers decreased after space flight, as did the activity of oxidative enzymes (particularly in rapid fibers of the vastus lateralis muscle).