不同鞋条件对后跟着地跑者跟腱负荷特征的影响

目的 探究不同鞋条件（极简鞋和传统跑鞋）对跑步时跟腱负荷特征的影响。方法 招募16名健康男性后跟着地跑步爱好者,要求其以3.16~3.50 m/s速度在两种鞋条件下完成跑步实验。采用超声影像仪获取跟腱横截面积成像。采用运动捕捉系统和三维测力台获取踝关节矢状面运动学和地面反作用力数据,并计算踝关节和跟腱的力学参数。采用配对样本t检验比较两种鞋条件对各因变参数（踝关节角度、触地角度、跟腱力、应力、应变等）的影响。结果 与传统跑鞋相比,穿着极简鞋时的足触地角度显著降低39.9%。同时,踝关节力矩、跟腱力峰值、跟腱负载率峰值和平均负载率均显著增加,而达到跟腱力峰值的时间显著减小。穿着极简鞋时的跟腱应力峰值、跟腱应变峰值及其应力率和应变率峰值也显著增加。结论 习惯穿着传统跑鞋并采用后跟着地的跑者在穿着极简鞋后显著增加了跟腱的负荷特征,建议该类跑者循序渐进地过渡至极简鞋,以适应性地提高跟腱承受负荷的能力。     

幼儿不同跑步着地方式的生物力学特征

文题释义：跑：跑是双脚交替接触地面的周期性运动，但跑有一个双脚都离开地面的腾空期。幼儿在 1 岁多开始学习跑步，最初是走跑结合的移动方式，由于身体发育不完善，下肢力量弱，平衡能力差，容易摔倒；到 2.5岁，幼儿跑步的腾空阶段明显；到 6岁，早期跑步的特点基本消失。 着地方式：指的是人体在跑步着地阶段足部接触地面的方式，一般分为3种方式：分别为足跟着地(fore foot strike)，跟骨先接触地面；全足着地(mid foot strike)，全脚掌着地，即足跟与前足同时接触地面；前足着地(rear foot strike)：前足部首先接触地面。 背景：成年人跑步着地方式一直是国内外学者研究的重点，而幼儿跑步的着地方式也是不容忽视的内容。 目的：运用生物力学方法探究幼儿在跑步过程中，不同着地方式下的运动学和动力学指标的差异，为幼儿正确的跑步着地方式提供科学依据。 方法：在北京市海淀区某公立幼儿园中随机抽取幼儿74名，按年龄分为3岁组、4岁组、5岁组，采用BTS红外动作捕捉系统、Kistler三维测力台和VIXTA录像解析系统同步采集幼儿跑步过程中不同着地方式下的运动学、动力学数据；运用Anybody 5.2仿真建模软件计算下肢肌肉力量指标。试验前向受试者父母详细解释并签署知情同意书，试验方案符合北京师范大学的相关伦理要求。 结果与结论：①3岁组全足着地的比例最高，足跟着地的比例最低，5岁组全足着地的比例最低，足跟着地的比例最高；前足着地者的蹬伸时间大于足跟着地(P < 0.01)和全足着地(P < 0.05)；②着地时刻，踝屈曲角度足跟着地者大于前足着地(P < 0.01)和全足着地者(P < 0.05)，全足着地者大于前足着地(P < 0.05)；前足着地者髋内收-外展角度、最大髋内收-外展角、髋内-收外展的关节变化量及最大膝内收-外展角速度大于足跟着地(P < 0.01)和全足着地者(P < 0.05)；前足着地者的踝屈伸最小值大于足跟着地者(P < 0.05)，而最大髋内收-外展角速度小于足跟着地者(P < 0.05)；③足跟着地和全足着地者的腓骨短肌、腓骨长肌、第三腓骨肌的肌力大于前足着地者(P < 0.05)，前足着地者的股中间肌、股外侧肌下束、股外侧肌上束、股内侧肌下束、股内侧肌上束、股内侧肌中束肌力均大于足跟着地(P < 0.01)和全足着地者(P < 0.05)；④结果提示：在3-6岁阶段，幼儿多采用足跟或全足着地模式进行奔跑，以满足自己在跑步过程的稳定性，随着年龄的增长，逐渐出现前足着地方式的跑步模式；前足着地能够动用更多髋关节和膝关节额状面的运动来维持人体运动中的稳定，足跟着地和全足着地能够动用更多的小腿前侧和后侧的肌力，而前足着地动用更多的大腿前侧肌力。 ORCID: 0000-0002-8337-3931(赵盼超) 中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程     

跑鞋与着地方式对跑步损伤的影响

长跑是骨骼肌肉系统损伤发病率最高的运动健身项目之一,与跑鞋和着地方式有很大关系。在百链云图书馆和谷歌学术数据库中检索有关跑鞋和着地方式与跑步损伤关系的生物力学研究,最终选择42篇进行文献综述,发表时间为1981~2016年。跑鞋所宣称的缓冲和动作控制的作用并未得到证实,裸足跑作为更自然的跑步方式得到提倡。前脚掌着地的跑步方式对膝关节的损伤更小,但踝关节和跖骨的负荷较大;后跟着地则相反。因此,跑步者应根据自身情况选择适合的跑步方式。但转变跑步方法对跑步者下肢生物力学特征的影响尚未明确,这方面的研究会对跑步者转变跑步方式提出更好的建议。     

不同角度制动对跟腱力学特性影响的实验研究

目的探讨不同角度制动对跟腱力学特性的影响.方法分别将兔踝关节于伸直位和背屈90°位制动4周,然后对跟腱本构方程、应力-应变关系等进行对照研究.结果正常组与二制动组之间跟腱的应力-应变关系理论曲线均有明显不同,其材料常数亦有显著差异;而在二个制动组之间却并不显著.结论"静止应力”并不能延缓制动所致的组织退变.     

足支撑时相跟腱不同拉力负荷时足底压力的分布

目的探讨足支撑时相跟腱不同拉力负荷过程中足底前、后部压力分布的变化。方法将6个新鲜足标本置于Bose材料试验机上,保持足标本中立位,调整垂直压力350 N不变,通过砝码分别给予跟腱0～80 kg不同级别(0、100、200、300、400、500、600、700、800 N)的拉力;分别放置两个秤在足底前、后部,记录足底前、后部在不同跟腱提拉力下的压力值。结果在跟腱不同提拉力下,前足底的压力值不断增加,后足底的压力值不断降低,前足底和后足底压力值占整个足底压力值的百分比与跟腱拉力呈线性关系(P<0.01,R2=0.996)。结论本研究模拟了人活体状态下足的支撑时相,探讨了支撑期足底前、后部压力值的变化趋势,为临床上一些由于跟腱收缩紊乱引起足底压力变化而导致的疾病(如糖尿病足底溃疡、跖骨痛)提供理论基础。     

跟腱运动功能与生物力学特征的研究进展

跟腱是连接足跟和足跖屈肌的关键结构,主要承担运动时小腿三头肌肌力的传递,是下肢在跑、跳时有效完成力/能量储存和释放的关键。现阶段,着地过程中跟腱的非同源性载荷以及过载后的无法完全恢复是跟腱损伤的首要原因,然而,针对预防跟腱损伤的相关手段并不能达到完全康复的效果。针对跟腱的运动功能及其在国内外生物力学领域的应用进行综述,重新考量跟腱在人体跑、跳运动中所起的作用,包括运动中跟腱内/外力学因素的系统关系、训练跟腱的有效方案。积极提升跟腱的力学特性,改善跟腱承受力,使之在一个较优范围,并最终达到提高运动表现,从源头上减少跟腱损伤,将是未来探究跟腱力学运动功能的关键。     

不同生物材料修复跟腱损伤的应用

背景：构建组织工程化肌腱的关键是寻找适于肌腱细胞黏附、生长及功能分化的支架材料。 目的：评价不同生物材料在跟腱损伤修复中的效果。 方法：以“生物材料,跟腱,修复” 为关键词在万方数据库中检索1985-01/2011-01关于生物材料治疗跟腱缺损的文章。 结果与结论：陈旧性跟腱断裂难以自行愈合及修复,易遗留疼痛及功能障碍。长期以来,不少学者对跟腱缺损的治疗进行了较多的研究,从自体肌腱移植、同种异体肌腱移植到人工肌腱移植、组织工程肌腱移植等,实践证明这些方法手段都存在一定的优点和缺点。虽然肌腱组织工程中支架材料的研究与应用已经取得了一些成功,但是目前应用的材料或存在生物相容性问题、降解性问题或存在力学性能差、难加工成型等缺陷,与理想的支架材料还存在很大差距。     

即刻改变触地方式对着鞋跑时内侧纵弓在体运动学的影响

目的 探究即刻转换触地方式对着鞋跑步时内侧纵弓在体运动学的影响。 方法 采用高速双平面荧光透视成像系统采集 15 名健康男性跑者即刻改变触地方式前后右足在跑步支撑阶段[跑速:(3±0. 15) m/ s]的荧光图像。根据 CT 图像重建第 1 跖骨和跟骨三维骨骼模型及其局部坐标系,并通过 3D-2D 配准获取内侧纵弓在跑步支撑期的 6 自由度(six degree of freedom,6 DOF) 数据(简化为第 1 跖骨相对跟骨的运动)。 采用一维统计参数映射(statistical parametric mapping,SPM)比较即刻改变触地方式前后内侧纵弓的 6 DOF 运动趋势,并对其特征值进行配对样本 t 检验。 结果 相比后跟跑,即刻前掌跑时,在支撑期的 15% ~ 21% 第 1 跖骨相对跟骨的外移、支撑期 17% ~45% 第 1 跖骨的前移和支撑期的 18% ~ 39% 第 1 跖骨的背屈均显著增加(P<0. 05)。 即刻前掌跑时,第 1 跖骨相对跟骨的前移最大值、背屈最大值、前后平移活动范围及内侧纵弓压缩变化量均显著增加(P<0. 05)。 结论 由习惯后跟跑即刻转换为前掌跑后,内侧纵弓矢状面的形变显著增加,尤其是内侧纵弓的压缩变化量增加约 10% ,可能有助于其弹性能量的储存与释放。     

miR-34a对脂肪干细胞移植治疗跟腱炎的影响

目的:探讨微小RNA-34a (miR-34a)的表达对人脂肪干细胞(hADSCs)移植治疗大鼠跟腱炎的影响。方法:CCK-8法检测h ADSCs被分别转染miR-34a mimic和miR-34a inhibitor 24 h、48 h、72 h和96 h后的细胞活力情况。注射胶原蛋白酶构建跟腱炎大鼠模型,建模后将大鼠随机分为5组:PBS注射对照组(PBS组)、h ADSCs治疗组(h ADSCs组)、转染阴性对照(NC)的h ADSCs治疗组(hADSCs+NC组)、转染miR-34a mimics的h ADSCs治疗组(h ADSCs+miR-34a组)和转染anti-sense miR-34a的h ADSCs治疗组(h ADSCs+anti-miR-34a组)。分离跟腱组织,检测跟腱组织的硬度、压力和最大负荷拉力等生物力学指标;利用RT-qPCR检测miR-34a及I型胶原蛋白(collagen I)、scleraxis (Scx)和生腱蛋白C(tenascin C,TNC) mRNA的表达水平; Western blot测定collagen I、Scx和TNC蛋白表达水平。结果:在体外过表达和敲减miR-34a可分别抑制和促进h ADSCs的活力; 5组大鼠跟腱组织生物力学测定结果显示,与PBS组相比,h ADSCs组大鼠跟腱组织硬度、压力和最大负荷拉力显著提高;与h ADSCs+NC组相比,h ADSCs+miR-34a组和h ADSCs+anti-miR-34a组分别显著降低和提高了上述生物力学指标。与PBS组相比,h ADSCs组大鼠collagen I、Scx和TNC的mRNA和蛋白表达水平上调;与h ADSCs+NC组相比,h ADSCs+miR-34a组miR-34a的表达水平升高,collagen I、Scx和TNC的mRNA和蛋白表达水平降低,而h ADSCs+anti-miR-34a逆转了上述趋势。结论:miR-34a通过调控脂肪干细胞活力和分化,影响跟腱炎的治疗效果。     

双蒂腓肠肌皮瓣修复跟腱复合缺损的改进及其解剖学依据

目的改进双蒂腓肠肌皮瓣下滑术式,细化其修复跟腱复合组织缺损适应证,减少供区创伤。方法0侧成人下肢标本,模拟只切断比目鱼肌近端附着点、保留跟腱远端完整性的双蒂腓肠肌V-Y推进皮瓣,测定膝关节不同屈曲角度下皮瓣下滑的距离。结果在膝关节屈曲0°、30°、60°、90°时,上述方法后双蒂腓肠肌皮瓣下滑的平均距离分别为(13.83±5.31)mm、(25.00±2.83)mm、(32.67±4.41)mm、(39.50±4.85)mm。结论双蒂腓肠肌V-Y下滑术式中只切断比目鱼肌近端附着点后重建,保留跟腱远端完整性的这一改进在解剖学上是可行的,适用于40mm以内的成人跟腱复合组织缺损。     

The Effect of Foot Strike Pattern on Achilles Tendon Load During Running

In this study we compared Achilles tendon loading parameters during barefoot running among females with different foot strike patterns using open-source computer muscle modeling software to provide dynamic simulations of running. Muscle forces of the gastrocnemius and soleus were estimated from experimental data collected in a motion capture laboratory during barefoot running for 11 runners utilizing a rearfoot strike (RFS) and 8 runners utilizing a non-RFS (NRFS) pattern. Our results show that peak Achilles tendon force occurred earlier in stance phase (p = 0.007), which contributed to a 15% increase in average Achilles tendon loading rate among participants adopting a NRFS pattern (p = 0.06). Stance time, step length, and the estimated number of steps per mile were similar between groups. However, runners with a NRFS pattern experienced 11% greater Achilles tendon impulse each step (p = 0.05) and nearly significantly greater Achilles tendon impulse per mile run (p = 0.06). This difference equates to an additional 47.7 body weights for each mile run with a NRFS pattern. Runners considering a NRFS pattern may want to account for these novel stressors and adapt training programs accordingly.     

Response of Rabbit Achilles Tendon to Chronic Repetitive Loading

The objective of this work was to assess the response of tendon to chronic repetitive loading. Controlled muscle stimulation was used to load the rabbit Achilles tendon at a frequency of 1.25 Hz for two hours per day, three days per week for a period of 11 weeks. Average peak tendon force was 26 N during the protocol. The loading protocol did not modify the gross morphology of the tissue, nor its water content or cellularity. Increases in mRNA expression of collagen Type III and MMPs were observed, but no signs of injury were detected by histologic examination of tendon and paratenon structures. The lack of a detectable injury response suggests that the tendons were not loaded beyond their capacity for repair. Factors additional to mechanical loading such as aging, illness or stress may be necessary to produce pathology.     

Changes of Achilles Tendon Reflex Amplitudes During a Fixed Foreperiod of Four Seconds

Preparation for a voluntary foot or finger response was studied by evoking Achilles tendon (T) reflexes. Reflexes were evoked simultaneously in both legs at 13 points between 100 and 4300 msec after the warning signal. With this paradigm, the time course of changes in reflex amplitudes related to preparatory processes could be measured simultaneously in the leg involved in the response and in the uninvolved leg. Immediately following the warning stimulus, the reflex amplitudes increased in both involved and non-involved muscles, presumably reflecting a general non-specific arousal. During the second half of the foreperiod, reflex amplitudes in non-involved muscles remained elevated, perhaps reflecting a general activation of the motor system, but returned to baseline in the involved muscles. It is hypothesized that the consistently smaller reflex amplitudes in the involved leg during the entire ISI reflect a presynaptic inhibition of the la afferents to the motoneurons involved in the response. Following the response stimulus, reflex amplitudes increased in both involved and non-involved muscles, although in the former at an earlier point and to a greater extent. It is suggested that this increase following the response stimulus is a manifestation of the transition from motor preparation to response execution.     

The Effect of the Achilles Tendon on Trabecular Structure in the Primate Calcaneus

Humans possess the longest Achilles tendon relative to total muscle length of any primate, an anatomy that is beneficial for bipedal locomotion. Reconstructing the evolutionary history of the Achilles tendon has been challenging, in part because soft tissue does not fossilize. The only skeletal evidence for Achilles tendon anatomy in extinct taxa is the insertion site on the calcaneal tuber, which is rarely preserved in the fossil record and, when present, is equivocal for reconstructing tendon morphology. In this study, we used high‐resolution three‐dimensional microcomputed tomography (micro‐CT) to quantify the microstructure of the trabecular bone underlying the Achilles tendon insertion site in baboons, gibbons, chimpanzees, and humans to test the hypothesis that trabecular orientation differs among primates with different tendon morphologies. Surprisingly, despite their very different Achilles tendon lengths, we were unable to find differences between the trabecular properties of chimpanzee and human calcanei in this specific region. There were regional differences within the calcaneus in the degree of anisotropy (DA) in both chimpanzees and humans, though the patterns were similar between the two species (higher DA inferiorly in the calcaneal tuber). Our results suggest that while trabecular bone within the calcaneus varies, it does not respond to the variation of Achilles tendon morphology across taxa in the way we hypothesized. These results imply that internal bone architecture may not be informative for reconstructing Achilles tendon anatomy in early hominins. Anat Rec, 296:1509–1517, 2013. © 2013 Wiley Periodicals, Inc.     

Motor Preparation: Changes in Amplitude of Achilles Tendon Reflexes During a Fixed Foreperiod of One Second

Achilles tendon (T) reflexes were evoked simultaneously in both legs during a fixed foreperiod of 1 sec. Volunteers were instructed to react as quickly as possible by one of four responses (in blocks): a plantar flexion of the left or right foot and a flexion of the left or right index finger. Prior to a foot response one leg was always involved in the response, prior to a finger response neither leg. Reflexes were evoked at 13 different points in time, from 100 msec prior to the warning signal (WS) to 100 msec after the response signal (RS). Amplitudes were expressed in percentages of control (intertrial interval) reflex amplitudes. In all conditions, amplitudes in both legs reached a peak 100 msec after the WS. After this non-selective increment, reflex amplitudes preceding a finger response decreased but remained larger than the baseline. Prior to a foot movement, amplitudes in uninvolved muscles remained larger than the baseline as well, whereas amplitudes in the involved muscle were no longer different from the baseline. This differential effect was independent of the response side. It was concluded that preparation for a response is characterized by a selective lack of activation in the reflex arc of the agonist, and a non-selective activation of the uninvolved spinal motor structures.     

伞式经跟骨缝合组合修复跟腱断裂的实验研究

目的 评价伞式经跟骨组合缝合法修复跟腱断裂的生物力学特性。方法 采用伞式经跟骨缝合法，组合应用0-薇乔线(Poliglactin-910)、腱周采用交叉缝合法修复8只家兔单侧跟腱断裂模型，术后固定3天，功能锻炼25天后行离体生物力学实验。结果术后28天组达正常组跟腱生物力学特性的90％。结论 采用伞式经跟骨组合缝合法修复跟腱允许早期康复活动，早期功能锻炼可以迅速提高跟腱的生物力学特性。     

Role of moderate exercising on Achilles tendon collagen crimping patterns and proteoglycans

Abstract

In this study, the morphological and morphometric changes in the collagen crimping pattern of Achilles tendon and metabolism/expression of tenocytes explanted from tendons of running (RUN) and sedentary (SED) rats were investigated to assess the effects of 12 weeks moderate running exercise. The number, the top angle width and the base length of each crimp in three different regions (proximal, central and distal) of RUN and SED tendons were measured with a polarized light microscope. The most significant morphometric differences in the crimps were detectable in the central region of the RUN tendons. In this region, crimps were fewer, larger and more flattened than those of other regions as a consequence of a functional adaptation of extracellular matrix to running, in order to increase tendon stiffness and force transmission efficiency. Conversely, the top angle width of the crimps reduced in proximal and distal regions of the RUN tendons, suggesting that these crimps might act as more reactive mechanical springs, able to store and improve the release of the stored strain energy in most loaded regions. Tenocytes explanted from Achilles tendons of both RUN and SED groups were cultured. Running influenced tenocytes which showed a significant increase in collagen type-I synthesis and proteoglycans production, suggesting enhancement of the loading transmission efficiency and facilitate inter-fibril and inter-fiber sliding.