慢跑的速度对青年女性下肢关节及肌肉的影响

目的 探讨合理的慢跑速度对体形和步姿的影响,使人在慢跑健身的同时兼得柔美的体态。方法 根据相关测量选择5种慢跑速度。利用运动捕捉系统采集研究对象(15位青年女性志愿者)在慢跑速度下的运动学数据,同时对下肢8块主要肌肉的肌电信号进行采集。计算获得在不同慢跑速度下髋、膝及踝关节矢状面的关节角度变化的均值。选择数据最接近均值的对象作为研究对象并进行运动学分析。结果 计算获得了该研究对象在不同慢跑速度下髋、膝及踝关节矢状面的关节角度以及下肢8块主要肌肉的激活度曲线。运用打分的方法,本文给出了研究对象慢跑速度、慢跑阶段、肌肉激活度与关节角度之间的关系。结论 各关节角的变化范围和各肌肉最大激活度并不随慢跑速度的变化而单调变化。本文为青年女性健身时选择适合自己的慢跑速度提供了参考。     

测量并分析上楼梯过程中下肢关节角变化

目的获取上楼梯运动过程中国人下肢关节活动范围的统计学数据,从而为大屈曲度人工关节设计提供依据。方法设计常规楼梯实验装置,利用运动捕捉系统(Optotrak Certus,NDI)和三维测力台(AMTI,Bertec),建立系统地测量上楼梯过程中下肢运动的方法,并应用此方法对40例样本进行测量。结果计算获得了40例样本在上楼梯过程中,髋关节、膝关节及踝关节在1个运动周期内沿各方向上关节角的变化规律及活动范围,其中髋、膝、踝关节在矢状面上活动范围分别是-1.6°～66.7°,0°～91.4°,-20.8°～22.4°。结论上楼梯运动过程中,髋、膝、踝关节在矢状面上活动度最大,且髋关节和膝关节屈曲度最大。与水平路面上正常行走和慢跑运动中关节运动范围比较,上楼梯运动中,髋关节和膝关节在矢状面上运动范围均较大。     

基于矢量编码技术研究功能性踝关节不稳者下肢协调性和变异性

目的 探索功能性踝关节不稳(functional ankle instability, FAI)人群在地面行走时的下肢协调性和协调变异性。 方法 12 名右侧 FAI 男性受试者(FAI 组)及配对招募 15 名健康男性受试者(对照组),以自选速度在地面上行走,运用 Qualisys 红外高速光学运动捕捉系统采集 5 min 步行的运动学数据,运用 Matlab 软件自编代码计算下肢关节间的耦合角及耦合角标准差。 耦合角采用圆形分布资料统计,耦合角标准差采用独立样本 t 检验。 使用Cohen’s d 评价效应量。 结果 FAI 组髋-膝关节矢状面耦合角在步态支撑中期前 1 / 2 和摆动期最后 1 / 4 均大于对照组;FAI 组髋-踝关节矢状面耦合角在支撑末期前 1 / 2 也大于对照组;膝-踝关节矢状面耦合角在支撑中期后 1 / 2和支撑末期前 1 / 2 均小于对照组。 FAI 组髋-踝关节冠状面耦合角在承重期 FAI 组比及摆动期最后 1 / 4 小于对照组。 在支撑末期及预摆期,FAI 组髋-踝关节冠状面和膝-踝关节矢状面耦合角标准差大于对照组。 结论 FAI 患者与正常人群的步态模式存在差异。 协调模式表现为某种代偿保护策略。 支撑末期及预摆期较大的协调变异性提示 FAI 患者踝关节感觉知觉的变化使髋、膝、踝关节的运动控制发生适应性变化     

模拟低重力下步态行走的下肢生物力学分析

目的研究重力水平对步态行走时下肢关节运动的影响规律。方法设计一种可随动悬吊式低重力模拟装置用于不同重力水平的模拟,利用运动捕捉系统和三维测力台对12名受试者在正常重力(1 G)、火星重力(1/3 G)及月球重力(1/6 G)下步态行走时下肢关节运动参数进行测量。结果重力水平降低后,髋、膝关节矢状面的活动范围显著减小(P0. 01),踝关节矢状面的活动范围显著增加(P0. 05),1 G重力下髋、膝关节、踝关节矢状面的活动范围分别为45. 2°、67. 7°、32. 5°,1/6 G重力下髋、膝、踝关节矢状面的活动范围分别为25. 1°、50. 8°、42. 4°。低重力环境下,下肢关节在矢状面上的关节力和力矩明显减小(P0. 01)。结论本研究得到的低重力下步态行走规律与以往使用跑步机得到的研究结果大体相同。航天员在地面可以使用跑步机在低重模拟装置的帮助下开展针对性的月面行走训练。     

穿戴式下肢外骨骼对人体步态特性的影响研究

本文拟探明穿戴式下肢外骨骼对人体下肢相应关节参数与肌肉运动学、动力学参数的影响变化,进而为优化其结构、提高其系统性能提供科学依据。本文通过采集受试者的行走数据,以人体下肢各关节在矢状面上的关节角度作为下肢外骨骼仿真分析的驱动数据,运用人体生物力学分析软件Anybody分别建立了人体模型(即未穿戴下肢外骨骼的人体模型)和人-机系统模型(即穿戴下肢外骨骼后的模型),并对比分析了两种情况下人体下肢运动时的运动学参数(关节力、关节力矩)及肌肉参数(肌肉力、肌肉激活程度、肌肉收缩速度、肌肉长度)的变化情况。实验结果表明,人体穿戴下肢外骨骼后行走的步态满足正常步态,但会出现个别肌肉力突增的现象;下肢主要肌肉的最大肌肉激活程度均未超过1,说明肌肉均未出现疲劳或损伤状况;股直肌的最大肌肉激活程度增加最多(0.456),半腱肌的最大肌肉激活程度增加最少(0.013),提示下肢外骨骼最容易引起股直肌疲劳或损伤。通过本文研究结果说明,为避免出现个别肌肉力突增导致人体下肢损伤,在设计下肢外骨骼时,要特别注意人体体段长与下肢外骨骼杆长的一致性和运动的平稳性。     

一种多自由度踝关节假肢的设计

为了适应不同的运动环境,设计了一款多自由度智能踝关节假肢.假肢具有球形踝关节结构,在运动过程中能实现矢状面和冠状面的自由运动,与配套控制系统共同作用,增加使用者的运动灵活性和稳定性,减少运动过程中的能量损耗,及时调整异常步态、步行速度、步幅等,辅助下肢截肢者自由行走.     

衰弱状态和步行速度对老年人下肢关节运动学特征的影响

目的 研究衰弱状态和步行速度对老年人步行时下肢关节运动学特征的影响。 方法 招募 59 名 60 岁及以上老年人,根据衰弱指数清单将受试者分为非衰弱组、衰弱前组和衰弱组,采用 Xsens MVN 运动捕捉惯性传感器采集 3 组老年人慢速、习惯速度、快速行走时的运动学数据,应用双因素重复测量方差分析比较不同衰弱状态和步速下老年人行走时的下肢关节运动学特征差异。 结果 衰弱组老年人的年龄显著高于非衰弱组(P<0. 01),膝关节最大屈角、膝关节和踝关节活动范围(range of motion,ROM)显著低于非衰弱组和衰弱前组(P<0. 05);同时,衰弱组老年人踝关节最大跖屈角显著低于非衰弱组(P<0. 05);随着步速增加,衰弱组老年人的单支撑相时间显著增加(P<0. 05),3 组老年人髋关节矢状面最大角及其 ROM、膝关节最大屈角、踝关节最大跖屈角及其 ROM 显著增加(P<0.05),双支撑相时间、踝关节最大背屈角度和膝关节 ROM 显著减小(P<0. 05);所有关节角度中只有髋关节最大伸角及其 ROM、膝关节最大屈角在慢速与习惯速度之间出现显著差异(P<0. 05)。 相关性分析显示,衰弱前组和衰弱组老年人不同速度步行时髋、膝关节 ROM 均显著正相关(P<0. 01),衰弱组老年人在习惯速度和快速行走时膝、踝关节 ROM 显著正相关(P<0. 05)。 结论 随着衰弱程度的进展,老年人下肢关节矢状面角度持续降低,主要集中于膝、踝关节。 在行走时两个关节间同步性增强,自由度降低,但在提高步行速度时,衰弱状态基本不影响老年人的步行策略。 研究结果有助于对衰弱老年人群进行筛查及康复指导。     

鞋跟高度对青年女性下楼梯步态的影响

目的 研究鞋跟高度对青年女性下楼梯步态的影响,分析女性穿高跟鞋下楼梯时的风险因素。方法 利用红外高速运动捕捉系统测试17名青年女性穿4种不同鞋跟高度皮鞋下楼梯的步态,计算受试者的步态时空参数和下肢关节角度。结果 与穿平跟鞋相比,穿3、5、7 cm高跟鞋下楼梯时步态周期增大,支撑相和双支撑相所占步态周期比例减小,步宽显著减小。与穿平跟鞋相比,穿5、7 cm高跟鞋下楼梯时踝关节矢状面内关节活动幅度均较小,穿3、5、7 cm高跟鞋时踝关节水平面内关节活动幅度均较大。穿3、5 cm高跟鞋时膝关节矢状面内关节活动度显著小于穿平跟鞋,穿3、5、7 cm高跟鞋时膝关节水平面内关节活动幅度显著大于穿平跟鞋。穿5、7 cm高跟鞋时髋关节最大屈曲角度显著大于穿平跟鞋,穿3、5、7 cm高跟鞋时髋关节最小屈曲角度显著大于穿平跟鞋。结论 随着鞋跟高度的增加,下楼梯时摆动期占步态周期百分比和步态周期都增大,而支撑相占步态周期百分比、双支撑相（后期）占步态周期百分比和步宽都减小,增加了下楼梯时跌倒的危险;同时,踝、膝关节矢状面内的关节活动幅度逐渐减小,水平面内的关节活动幅度增大。研究结果有助于深入了解鞋跟高度对穿着者下楼梯步态的影响特征和规律,为分析下楼时可能出现的损伤危险提供依据。     

基于表面肌电信号的不同步行速度下肌肉协同及肌肉功能网络分析

深入了解步行过程中的下肢肌肉协作机制是提高神经肌肉功能障碍患者步态康复疗效的关键。本文研究了步行速度的变化对下肢肌肉协同模式及肌肉功能网络的影响。招募了8名健康受试者分别以三种不同速度在跑步机上执行步行任务，同步采集右下肢8块肌肉的表面肌电信号（sEMG），通过非负矩阵分解（NNMF）方法提取肌肉协同模式，利用互信息（MI）方法分别构建alpha频段（8～13 Hz）、beta频段（14～30 Hz）和gamma频段（31～60 Hz）肌肉功能网络，引入复杂网络分析方法量化不同网络差异。肌肉协同分析提取到5个肌肉协同模式，步行速度的变化没有改变肌肉协同的数量，但导致了肌肉权值的变化；肌肉网络分析发现在同一速度下，高频段具有更低的全局效率和聚类系数，随着步行速度的增加，局部肌肉之间的连接强度增加。研究结果表明不同速度的步行运动存在不同的肌肉协同模式和肌肉功能网络，本研究为探索不同步行速度下肌肉协同机制提供了新的视野，有望为神经肌肉功能障碍患者的步态功能评估提供理论支撑。     

踝关节外骨骼助行模式对下肢肌肉激活与协调模式的影响EI北大核心CSCD

踝关节外骨骼可用来提高人的行走效率,辅助老年人、运动功能障碍患者等进行日常活动或康复训练,但外骨骼的助行模式会对穿戴者的下肢肌肉激活与协调模式产生影响。本文利用一款绳驱动踝关节外骨骼,设计了不同助力时机与助力大小组合的助行模式,采集了7名穿戴者在跑步机上以1.25 m/s速度水平行走时的下肢表面肌电信号,研究不同助行模式对穿戴者下肢肌肉激活与协调模式的影响。实验结果表明,比目鱼肌激活程度在踝关节外骨骼助力时有明显降低,在助力时机为步态周期49%、助力大小为0.7 N·m/kg时,最高可降低(38.5±10.8)%。并且,相对于助力时机,助力大小对比目鱼肌激活程度影响更为显著。踝关节外骨骼不同模式助行时,所测量下肢肌肉可分解为5个基本协同模式,且合适的助力时机与助力大小条件下,下肢肌肉协调模式和正常行走相比改变较小。此外,比目鱼肌-胫骨前肌、股直肌-半腱肌的协同收缩度在外骨骼助力时比正常行走均有升高。本研究有助于理解健康穿戴者如何调整自身的神经肌肉控制机制来适应不同外骨骼助力,并为选择合适的助行模式以及合理利用外骨骼提高行走效率提供依据。     

Asymptomatic Genu Recurvatum reshapes lower limb sagittal joint and elevation angles during gait at different speeds

BackgroundKinematic characteristics of walking with an asymptomatic genu recurvatum are currently unknown. The objective of this study is to characterize the lower limb sagittal joint and elevation angles during walking in participants with asymptomatic genu recurvatum and compare it with control participants without knee deformation at different speeds.MethodsThe spatio-temporal parameters and kinematics of the lower limb were recorded using an optoelectronic motion capture system in 26 participants (n = 13 with genu recurvatum and n = 13 controls). The participants walked on an instrumented treadmill during five minutes at three different speeds: slow, medium and fast.ResultsParticipants with genu recurvatum showed several significant differences with controls: a narrower step width, a greater maximum hip joint extension angle, a greater knee joint extension angle at mid stance, a lower maximum knee joint flexion angle during the swing phase, and a greater ankle joint extension angle at the end of the gait cycle. Participants with genu recurvatum had a greater minimum thigh elevation angle, a greater maximum foot elevation angle, and a change in the orientation of the covariance plane. Walking speed had a significant effect on nearly all lower limb joint and elevation angles, and covariance plane parameters.ConclusionOur findings show that genu recurvatum reshapes lower limb sagittal joint and elevation angles during walking at different speeds but preserves the covariation of elevation angles along a plane during both stance and swing phases and the rotation of this plane with increasing speed.     

基于深度学习融合算法的无标记点步态分析系统

目的 以有标记点三维运动捕捉系统(MoCap)为金标准,基于双向长短时记忆(bi-lateral long short term memory, BiLSTM)递归神经网络和线性回归算法构建深度学习融合模型,减小深度传感器的系统误差,从而提高深度传感器下肢运动学分析的准确性。方法 招募10名健康男性大学生进行步态分析,应用MoCap系统和Kinect V2传感器同时采集数据。通过Cleveland Clinic及Kinect逆运动学模型分别计算下肢关节角度。以MoCap系统为目标,Kinect系统得到的角度为输入构建数据集,分别用BiLSTM算法和线性回归算法构建学习模型,得到系统误差修正后的下肢关节角度。使用留一交叉验证法评估模型的性能。采用多重相关系数(coefficient of multiple correlations, CMC)及均方根误差(root mean square error, RMSE)表示下肢关节角度波形曲线相似程度以及平均误差。结果 BiLSTM网络比线性回归算法更能够处理高度非线性的回归问题,尤其是在髋关节内收/外展、髋关节内旋/外旋和踝关节趾屈/背屈角度...     

Asymmetric knee loading at heel contact during walking in patients with unilateral knee replacement

Increased load on the knee joint by excessive levels of impact forces during initial contact has been suggested to lead to knee osteoarthritis (OA). Asymmetric loading after knee replacement may also relate to the development of OA in the contralateral limb, therefore this study investigated the heel strike transient vertical force and subsequent lower extremity kinematic, kinetic and spatio-temporal parameters during level walking between the operated and the contralateral limbs in patients 12 months following unilateral knee replacement. A six camera motion analysis system with a force plate was used to investigate the differences between limbs in the heel strike transient vertical GRF and its relative timing, and hip, knee and ankle angles and moments at initial contact, as well as spatio-temporal parameters during the stance phase of walking in 19 subjects with unilateral knee replacement. Paired t tests showed a significant difference in the contralateral limb relative to the operated limb in the heel strike transient magnitude (p=0.03), hip moment (p=0.01), knee moment (p=0.02) and ankle moment (p=0.03). No significant differences were found for the joint angles at heel contact or the spatio-temporal parameters (p>0.05). The heel strike transient magnitude was lower for the operated limb with no differences in the spatio-temporal parameters or the joint angles at initial contact between the limbs. Differences in the hip, knee and ankle moments were also found indicating an asymmetric loading of the impact force at initial contact on the lower extremity. The current findings may indicate an asymmetric loading on the knee joint and therefore may be clinically relevant in patients undergoing unilateral knee replacement.     

Femoral Condyle Curvature is Correlated with Knee Walking Kinematics in Ungulates

The knee has been the focus of many studies linking mammalian postcranial form with locomotor behaviors and animal ecology. A more difficult task has been linking joint morphology with joint kinematics during locomotor tasks. Joint curvature represents one opportunity to link postcranial morphology with walking kinematics because joint curvature develops in response to mechanical loading. As an initial examination of mammalian knee joint curvature, the curvature of the medial femoral condyle was measured on femora representing 11 ungulate species. The position of a region of low curvature was measured using a metric termed the “angle to low curvature”. This low‐curvature region is important because it provides the greatest contact area between femoral and tibial condyles. Kinematic knee angles during walking were derived from the literature and kinematic knee angles across the gait cycle were correlated with angle to low curvature values. The highest correlation between kinematic knee angle and the angle to low curvature metric occurred at 20% of the walking gait cycle. This early portion of the walking gait cycle is associated with a peak in the vertical ground reaction force for some mammals. The chondral modeling theory predicts that frequent and heavy loading of particular regions of a joint surface during ontogeny will result in these regions being flatter than the surrounding joint surface. The locations of flatter regions of the femoral condyles of ungulates, and their association with knee angles used during the early stance phase of walking provides support for the chondral modeling theory. Anat Rec, 298:2039–2050, 2015. © 2015 Wiley Periodicals, Inc.     

基于不同刚体模型对老年女性步态的仿真研究

目的比较不同的多刚体模型在模拟老年女性步行过程中的仿真精度,并在最优模型的基础上探索行走速度对膝关节负荷的影响。方法在人体运动仿真软件ADAMS/Life MOD中分别建立19个环节(M1)、16个环节(M2)和12个环节(M3)的个性化人体模型和地面,并依次进行步态的仿真研究。结果综合比较3种模型仿真得到的垂直地面反作用力、步行时间和下肢关节角度,M2模型最适用于重现步态的实际情况。当老年女性加快步行速度时,垂直地面反作用力峰值、膝关节力矩和功率峰值都得到明显提高。结论建议老年女性多加强股四头肌的力量锻炼,以改善其步行行为。同时,研究结果在临床上也可为膝骨关节炎患者的康复治疗提供参考依据。     

下肢不等长对步态影响的实验分析

目的采用正常人体单侧增高模拟下肢不等长,分析下肢不等长步态特征,研究下肢不等长对步态的影响,为下肢假肢穿戴者因下肢不等长引起的慢性疾病提供理论依据。方法通过单侧穿鞋增高人为制造下肢不等长,利用三维动态捕捉系统和地面反力采集设备采集受试者在正常步态和下肢不等长步态下的时空参数、地面反力和关节角度,并进行对比分析。结果下肢不等长步态与正常步态在步长、步长时间和单侧支撑期存在显著差异。下肢不等长步态左右腿足跟着地期垂直方向地面反力均大于正常步态,髋、膝、踝角度存在明显变化。结论下肢不等长是造成行走步态异常的重要原因,可能是下肢假肢穿戴者产生腿部关节疾病的原因。     

Effect of medial foot loading self-practice on lower limb kinematics in young individuals with asymptomatic varus knee alignment

BackgroundVarus alignment of the knee is a risk factor for developing knee osteoarthritis. Recently, voluntary shifting the plantar pressure distribution medially (medial foot loading) during gait has been found to reduce knee adduction angle during stance, which may lower the joint load. However, it is not yet known whether such effect would persist after long-term self-practice. This study aimed to determine whether medial foot loading can be an effective self-care protocol for reducing the knee adduction angle.MethodsEight subjects with asymptomatic varus knee alignment were trained on medial foot loading once in a laboratory, then carried out as self-practice for 8 weeks outside the laboratory. Spatiotemporal gait parameters and lower limb joint kinematics data were collected during natural walking prior to the training (baseline walking), during the practice session immediately after the initial training (trained walking), and during natural walking after the self-practice period (post-practice walking).ResultsParticipants walked significantly faster after the self-practice period with longer step length compared with the baseline. The knee adduction angle at initial contact, maximum angle during stance, and mean angle during a gait cycle were significantly decreased during both the trained and post-practice walking compared with baseline. The 8-week self-practice caused larger decrements in the three angles than the single training, but no significant differences were found between the two conditions.ConclusionsSelf-practice of medial foot loading walking could be an effective gait strategy to reduce the knee adduction angle. The effect could be sustained for individuals with asymptomatic varus knee alignment.     

老年人上下楼梯的步态特征以及下肢关节运动功能特点

目的 探讨老年人上下楼梯的步态特征以及下肢关节运动的力学性能。 方法 通过17名青年人、15名老年人自然速度上下5个台阶的楼梯测试与分析,并结合红外高速运动捕捉系统和三维测力台获取步态参数、下肢关节角度以及地面反作用力,通过逆向动力学方法计算关节力矩和功率,采取独立样本 t 检验分析年龄对上述参数的影响。 结果 与青年人相比,老年人上下楼梯步态周期较长,步速和步频则明显较低(P<0. 05);同时,老年人上下楼梯支撑相和摆动相分别明显延长和缩短(P<0. 05)。 不论是青年人还是老年人,上下楼梯过程中下肢关节角度、力矩和功率的变化趋势较为一致。 但老年人上楼主要是通过踝、膝关节功率的产生来维持,而青年人则是通过近端肢体的能量,特别动用了较多的膝关节功率。 下楼过程中的能量吸收,两者皆是以膝关节为主。 结论 随着年龄的增长,下肢机能下降和肌力不足,老年人害怕在上下楼梯时发生跌倒,试图通过减少摆动时间来弥补身体的不稳定。 研究结果为临床上老年患者群体的康复管理以及预测跌倒的功能性评估提供参考。     

Knee osteoarthritis affects the distribution of joint moments during gait

Alterations in lower extremity kinetics have been shown to exist in persons with knee osteoarthritis (OA), however few investigations have examined how the intersegmental coordination of the lower extremity kinetic chain varies in the presence of knee joint pathology. The objective of this study was to evaluate how knee OA and walking speed affect total support moment and individual joint contributions to the total support moment. Fifteen healthy subjects and 30 persons with knee OA participated in 3D walking analysis at constrained (1.0 m/s), self-selected and fastest tolerable walking speeds. Individual joint contributions to total support moment were analyzed using separate ANOVAs with one repeated measure (walking speed). Linear regression analysis was used to evaluate the relationship between walking speed and joint contribution. Persons with knee OA reduced the contribution of the knee joint when walking at constrained (p = 0.04) and self-selected walking speeds (p = 0.009). There was a significant increase in the ankle contribution and a significant decrease in the hip contribution when walking speed was increased (p < 0.004), however individual walking speeds were not significantly related to joint contributions. This suggests that the relationship between walking speed and joint contribution is dependent on the individual's control strategy and we cannot estimate the joint contribution solely based on walking speed. The slower gait speed observed in persons with knee OA is not responsible for the reduction in knee joint moments, rather this change is likely due to alterations in the neuromuscular strategy of the lower extremity kinetic chain in response to joint pain or muscle weakness.