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     

改变步频对无氧阈跑速下能量消耗、表面肌电和步态特征的影响

背景:长跑训练中流行的观点是通过提高步频可以提高跑步效率,这需要多方面的科学评价及研究。目的:通过比较个体无氧阈强度下自选步频与改变步频后机体的心率、摄氧量、表面肌电和步态特征的变化,探究改变步频对跑者产生的影响,为提高跑步效率提供科学策略。方法:选择12名男性马拉松跑步爱好者。在试验开始前,首先通过跑台递增负荷试验进行有氧能力测试,得到跑者的通气无氧阈及无氧阈速度。在正式试验开始后,采用随机交叉设计,在无氧阈跑速下,进行自选步频、自选步频±5%和自选步频±10%跑台测试。使用配对t检验和皮尔逊相关分析等方法对心率、摄氧量、表面肌电和步态特征等指标进行统计分析,探究改变步频后各指标的变化规律。研究方案的实施符合北京体育大学的相关伦理要求,受试者对试验过程完全知情同意。结果与结论:(1)心率和摄氧量:改变步频后,心率显著增加(P <0.01),步幅发生显著变化(P <0.01),自选步频-5%(P <0.05)和自选步频±10%(P <0.01)时摄氧量显著增加;步幅和与摄氧量呈正相关关系(r=0.57,P <0.01),步频/步幅与摄氧量呈负相关关系(r=...     

正常青年人三维步态:时空及运动学和运动力学参数分析

背景:三维步态分析作为一种客观步态评估方法越来越广泛应用于临床检测。但尚缺乏统一的标准来衡量正常人的步态特征。目的:检测中国正常青年人自然行走步态数据,为临床上异常步态的分析提供参考依据。方法:应用英国Vicon三维运动捕捉系统,对100名正常青年人进行步态测试,得到时空参数、运动学参数、运动力学参数。结果与结论:正常青年人左右侧(髋、膝、踝关节的活动角度和垂直地板反力)曲线分布规律基本一致;髋、膝、踝关节活动角度(最初着地角度、最大屈曲角度、最大伸展角度、矢状面最大活动范围)和垂直地板反力参数(第1波峰值、谷值、第2波峰值)的左右侧相比,差异无显著性意义(P0.05)。说明建立的中国正常人步态数据,可供临床步态分析参考使用。     

步态周期中踝关节有限元模型的构建及生物力学分析

背景:踝关节属于人体最重要的承重关节之一,在行走过程中发挥着重要作用,目前缺少有关踝关节在步态周期中应力的相关研究。目的:基于有限元法分析步态周期中踝关节的应力大小及区域变化。方法:首先通过Mimics 16.0软件及Rapidform XOR364软件构建踝关节有限元模型;利用此踝关节模型与Anderson构建的胫距下关节面有限元模型的应力及接触面积进行对比,验证模型的有效性;最后通过ABAQUS有限元分析软件,模拟踝关节在步态周期中平衡站立工况及支撑末期工况的应力状态,通过对比相同区域不同工况的应力变化,分析踝关节在步态周期中的作用,探讨踝关节失稳状态下踝关节的应力变化。结果与结论:(1)构建的踝关节有限元模型共包括44 551个单元、16 718个节点,并验证了其有效性与合理性;(2)平衡站立工况下:主要应力集中在距腓前韧带(A、B)、胫距前韧带(C、D)、胫距后韧带近端(F)、胫距关节下表面(H);踝关节最大应力在胫距后韧带近端附着点(F),为10.670 MPa;最小应力在内踝胫骨关节面(J),为2.965 MPa;(3)支撑末期工况下:主要应力集中在距腓前韧带(A、B)、胫...     

痉挛型脑瘫患者功能性选择性脊神经后根切断术前后的三维步态特征分析

目的分析痉挛型脑瘫患者功能性选择性脊神经后根切断(functional selective posterior rhizotomy,FSPR)手术前后的步态特征,客观量化评估手术疗效。方法选取15名将要进行FSPR手术治疗的痉挛型脑瘫患者,应用VICON三维运动捕捉系统结合AMTI三维测力台对患者进行手术前后的步态采集,分析手术前后步态的时空、运动学及动力学参数。结果手术后,左、右支撑时间均大于手术前,左侧步长明显大于手术前,步高、步速及冠状面重心偏移均小于手术前;着地时的膝关节矢状面角度(即屈伸角度)出现明显提高,髋、踝关节未见明显差异。手术后,步行过程中左右侧髋、膝、踝关节活动范围(range of motion,ROM)在矢状面均出现不同程度的提高,且有统计学差异;右踝关节冠状面ROM也出现明显提高。手术后,右膝关节最小屈曲角度及左、右踝关节最大跖屈角度均出现显著减小;左、右侧支撑相最大垂直力较手术前明显提高,而下肢关节力矩未见明显差异。结论三维步态分析可以在一定程度上评估痉挛型脑瘫患者FSPR手术的疗效。术后痉挛型脑瘫患者的痉挛得到缓解,对步态的时空参数及下肢关节运动学参数改善比较明显,而对于动力学参数改善相对不明显,需进行进一步康复治疗。     

脑卒中患者运动过程中动力学特征的智能预测

目的 使用主成分分析（principal component analysis,PCA）和反向传播(back propagation,BP)神经网络预测脑卒中患者行走时患侧髋、膝、踝的关节力矩。方法 30例脑卒中患者通过8镜头Qualisys红外光点高速运动捕捉系统和Kistler三维测力台同步采集运动学和动力学数据。通过OpenSim计算脑卒中患者髋、膝、踝患侧关节力矩,采用PCA来筛选累积贡献率达到99%的初始变量,采用标准均方根误差（normalized root mean squared error,NRMSE）、均方根误差（root mean squared error,RMSE）、平均绝对百分比误差（mean absolute percentage error,MAPE）和平均绝对误差（mean absolute error,MAE）、R2作为PCA-BP模型的评价指标。使用肯德尔W系数评价计算关节力矩与预测力矩之间的一致性。结果 PCA数据显示躯干、骨盆、患侧髋、膝和踝关节在x、y、z轴（矢状、冠状、垂直轴）对患侧髋、膝、踝关节力矩具有显著影响。预测值与测量值间NRMSE为5.14%~8.86%,RMSE为0.184~0.371,MAPE为3.5%~4.0%,MAE为0.143~0.248,R2为0.998~0.999。结论 建立的PCA-BP模型可准确预测脑卒中患者行走时的髋膝踝关节力矩,显著缩短测量时间。在脑卒中患者的步态分析中本模型可代替传统的关节力矩计算,为获得脑卒中患者生物力学数据提供新途径,以及为脑卒中患者临床治疗提供有效的方法。     

跑姿再训练对冲击力、下肢生物力学及刚度的影响

目的 通过建立12周跑姿再训练（gait retraining,GR）的干预模式（即通过一定的姿态目标改变跑者原有跑姿）,确定GR前后跑步时垂直地面反作用力（vertical ground reaction force, vGRF）以及髋、膝、踝三关节运动学、动力学和下肢刚度特征的变化,探究跑姿转换对冲击力和下肢生物力学的影响。方法 采用Vicon 运动捕捉系统和Kistler三维测力台同步采集30名跑步爱好者（GR组15人,对照组15人）GR前后穿着极简鞋以 12 km/h±5%速度通过测力台的GRF以及标记点轨迹。结果 共17名受试者（GR组9人,对照组8人）完成训练。训练后两组最大负载率都显著下降,GR组相比对照组最大负载率更低;GR组足部触地角度显著减小,两组跖屈角度和髋关节蹬伸角速度都显著增加;GR组踝关节力矩增加;两组下肢刚度均显著增加。结论 成功建立12周GR运动干预模型（前掌着地转化率为78%）。GR能有效避免冲击力峰值、降低最大负载率、提高下肢刚度,进而在减小甚至避免由冲击力引起的跑步损伤风险的同时,为提高跑步经济性提供可能。     

不同跑步着地习惯对跟腱形态学及其负荷特征的影响

目的 探究不同着地模式对跟腱形态学和负荷特征的影响。方法 招募习惯后跟着地跑者和习惯前掌着地跑者各14人,利用超声医学影像仪采集受试者的跟腱形态学特征（跟腱长度、横截面积、厚度）;利用三维测力跑台采集并计算受试者穿着缓冲跑鞋以10 km/h速度跑步时的跟腱负荷特征（跖屈力矩、跟腱力、负载率、冲量、应力等）。结果 与习惯后跟着地跑者相比,习惯前掌着地跑者踝关节跖屈力矩峰值、跟腱力峰值、平均负载率、峰值负载率均显著增加（P＜0.05）,但两组跑者跟腱长度、跟腱横截面积和跟腱厚度差异无统计学意义（P＞0.05）。结论 长期的前掌着地模式可以适应性地提高跟腱在重复性的“拉长-收缩”循环刺激中的力学特性。深入理解跟腱在不同着地方式下的响应,对于跑步爱好者以及运动医学领域中预防跟腱相关损伤具有重要的临床意义。     

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。     

步态分析技术评估人工踝关节置换前后踝关节功能的改善程度

背景：人工踝关节置换目前得到了广泛的应用,疗效也得到了一定的认同,但目前的疗效评估多是通过各类评分标准进行评估,但对于踝关节置换后患者步态改变尚缺乏研究。 目的：通过Kofoed评价系统及步态分析技术比较人工踝关节置换患者置换前置换后踝关节功能的改善程度。 方法：收集2007-09/2011-06在上海交通大学医学院附属仁济医院骨科进行人工踝关节置换的患者,对其置换前后行Kofoed评分及步态分析,并与15例正常对照者进行比较,观察置换前后患者踝关节功能的改变。 结果与结论：人工踝关节置换后,Kofoed评分及步态参数步长、步速、患侧单腿支撑时间、双腿支撑时间、患侧踝关节、健侧踝关节、患侧髋关节、患侧膝关节、健侧膝关节行进中关节最大活动度出现明显改善(P < 0.05)。     

Lower extremity mechanical work during stance phase of running partially explains interindividual variability of metabolic power

Recent attention given to the mechanical work of the lower extremity joints, the emerging importance of the stance phase of running, and the lack of consensus regarding the biomechanical correlates to economical running were primary justifications for this study. The purpose of this experiment was to identify the correlations between metabolic power and the positive and negative mechanical work at lower extremity joints during stance. Recreational runners (n = 16) ran on a treadmill at 3.35 m s⁻¹ for physiological measures and overground for biomechanical measures. Inverse dynamics were used to calculate net joint moments and powers at the ankle, knee, and hip. Joint powers were then integrated over the stance phase so that positive and negative joint mechanical work were correlated with metabolic power (r = 0.60–0.69). Positive work at the hip and ankle during stance was positively correlated to metabolic power. In addition to these results, more economical runners (lower metabolic power) exhibited greater negative work at the hip, greater positive work at the knee, and less negative work at the ankle. Between the most and least economical runners, different mechanical strategies were present at the hip and knee, whereas the kinetics of the ankle joint differed only in magnitude.     

基于统计参数映射分析跑鞋跟掌落差对下肢关节负荷的影响

目的 探讨在相同跑速下穿着不同落差跑鞋对下肢关节负荷的影响,为跑鞋设计和跑步者选购跑鞋提供依据。方法 18名男性跑步者分别穿着零落差和10 mm落差跑鞋以(4.0±0.2) m/s速度完成测试,使用红外高速运动捕捉系统和三维测力台同步采集下肢运动学参数和地面反作用力(ground reaction force, GRF)。使用统计参数映射法(statistical parameter mapping, SPM)分析跑鞋跟掌落差对支撑期垂直GRF、下肢关节三维力矩的影响。结果 跑鞋跟掌落差对垂直GRF无影响,对下肢关节部分力矩-时间序列影响显著。与穿着零落差跑鞋相比,穿着10 mm落差跑鞋在27%～38%支撑期髋关节内旋力矩增加,在47%～75%支撑期膝关节伸展力矩增加,在16%～33%、25%～30%、12%～25%支撑期踝关节跖屈力矩、外翻力矩和外旋力矩降低。结论 与穿着零落差跑鞋相比,穿着10 mm落差跑鞋在支撑前期髋关节负荷增加,踝关节负荷降低,在支撑中期膝关节负荷增加。建议跑步者结合自身特点及跑鞋跟掌落差对下肢关节负荷特征的影响,选择适合自己的跑鞋。     

Reduced plantar cutaneous sensation modifies gait dynamics, lower-limb kinematics and muscle activity during walking

Peripheral neuropathy is the most common long-term complication in diabetes and is involved in changes in diabetic gait and posture. The regression of nerve function leads to various deficits in the sensory and motor systems, impairing afferent and efferent pathways in the lower extremities. This study aimed to examine how reduced plantar-afferent feedback impacts the gait pattern. Cutaneous sensation in the soles of both feet was experimentally reduced by means of intradermal injections of an anaesthetic solution, without affecting foot proprioception or muscles. Ten subjects performed level walking at a controlled velocity before and after plantar anaesthesia. Muscle activity of five leg-muscles, co-contraction ratios for the knee and ankle joint, ground reaction forces (GRF), spatiotemporal characteristics, joint angles and moments of the hip, knee and ankle were analysed. The intervention significantly lowered plantar sensation, reducing it to the level of sensory neuropathy. Spatiotemporal gait characteristics remained unchanged. The ankle joint was more dorsiflexed which coincided with increased tibialis anterior and decreased gastrocnemius medialis muscle activity during foot flat to mid-stance. In addition, the knee joint was more flexed accompanied by increased biceps femoris activity and higher internal knee-extension moment. With regard to gait dynamics, a delay of the first peak of the vertical GRF was observed. Increased soleus and tibialis anterior muscle activity were found during the end of stance. Short-term loss of plantar sensation affects lower-limb kinematics and gait dynamics, particularly during the first half of stance, and contributes to modified muscle-activation patterns during locomotion.     

Limited knee extension during gait after total knee arthroplasty is related to a low Oxford Knee Score

BackgroundAfter total knee replacement (TKR) some patients report low self-perceived function, which is clinically measured using patient reported outcome measures (PROMs). However, PROMs, e.g. the Oxford Knee Score (OKS), inherently lack objective parameters of knee function. Biomechanical gait analysis is an objective and reliable measurement to quantitatively assess joint function. Therefore, the aim of this study was to explore the relationship between biomechanical gait parameters and the OKS.MethodsGait analyses were recorded in 37 patients at least one year after primary TKR and in 24 healthy controls. Parameters from this analysis were calculated for hip, knee and ankle joint angles and joint moments in the sagittal and frontal plane including initial contact, early, late stance and swing. For the patients these parameters were expressed as its difference to control values at matched walking speed. Linear regression analyses were performed between the parameters from gait analysis and the OKS, with speed as covariate.ResultsThe difference in knee extension angle at initial contact and late stance between patients and controls was significantly related to the OKS. Per one degree knee extension difference increase, the OKS reduced with 1.0 to 1.6 points. Overall, patients extended their knee less than controls. Neither ankle and hip gait parameters, nor joint moments showed a relation with OKS.ConclusionsAll patients with a submaximal score on the OKS showed limited knee extension during gait, even without a mechanical constraint in knee extension. This could be related to motor control limitations in this patient group.     

Ageing effects on knee and ankle joint angles at key events and phases of the gait cycle

The objective of this research was to determine whether joint angles at critical gait events and during major energy generation/absorption phases of the gait cycle would reliably discriminate age-related degeneration during unobstructed walking. The gaits of 24 healthy adults (12 young and 12 elderly) were analysed using the PEAK Motus motion analysis system. The elderly participants showed significantly greater single (60.3% versus 62.3%, p < 0.01) and double ( p < 0.05) support times, reduced knee flexion (47.7 degrees versus 43.0 degrees , p < 0.05) and ankle plantarflexion (16.8 degrees compared to 3.3 degrees , p = 0.053) at toe off, reduced knee flexion during push-off and reduced ankle dorsiflexion (16.8 degrees compared to 22.0 degrees , p < 0.05) during the swing phase. The plantarflexing ankle joint motion during the stance to swing phase transition (A2) for the young group (31.3 degrees ) was about twice ( p < 0.05) that of the elderly (16.9 degrees ). Reduced knee extension range of motion suggests that the elderly favoured a flexed-knee gait to assist in weight acceptance. Reduced dorsiflexion by the elderly in the swing phase implies greater risk of toe contact with obstacles. Overall, the results suggest that joint angle measures at critical events/phases in the gait cycle provide a useful indication of age-related degeneration in the control of lower limb trajectories during unobstructed walking.     

Influence of the instrumented force shoe on gait pattern in patients with osteoarthritis of the knee

Osteoarthritis (OA) of the knee is associated with alterations in gait. As an alternative to force plates, instrumented force shoes (IFSs) can be used to measure ground reaction forces. This study evaluated the influence of IFS on gait pattern in patients with knee OA. Twenty patients with knee OA walked in a gait laboratory on IFS and control shoes (CSs). An optoelectronic system and force plate were used to perform 3D gait analyses. A comparison of temporal-spatial gait parameters, kinematics, and kinetics was made between IFS and CS. Patients wearing IFS showed a decrease in walking velocity and cadence (8%), unchanged stride length, an increase in stance time (13%), stride time (11%) and step width (14%). No differences were found in knee adduction moment or knee kinematics. Small differences were found in foot and ankle kinematics (2–5°), knee transverse moments (5%), ankle frontal (3%) and sagittal moments (1%) and ground reaction force (1–6%). The gait of patients with knee OA was only mildly influenced by the IFS, due to increased shoe height and weight and a change in sole stiffness. The changes were small compared to normal variation and clinically relevant differences. Importantly, in OA patients no effect was found on the knee adduction moment.     

Immediate effects of a controllable knee ankle foot orthosis for functional compensation of gait in patients with proximal leg weakness

Application of intermittent control of the knee joint stiffness in a knee ankle foot orthosis (KAFO) during gait is proposed. The approach combines inertial sensors and an actuator system in order to apply compensation in quadriceps weakness with a wearable device. Two methods, segment-angular rotation based and segment-angular velocity based, are analysed for the control of the knee joint state (intermittent stiffness) based on the inertial sensors signals. Protocolled tests are developed with two post-polio syndrome patients (PPS). In this study, the cases of gait with free-swinging leg and safe stance with the orthotic system are presented in terms of quantified kinematics (average peak angle of knee flexion of 50°) and evidences of reduction of frequent compensations (e.g. leg lateral movement) in post-polio syndrome patients. The results from immediate inspection indicate an important improvement of the gait patterns in two patients with proximal leg weakness by means of compensations applied by the wearable orthosis.     

Ageing effects on knee and ankle joint angles at key events and phases of the gait cycle

The objective of this research was to determine whether joint angles at critical gait events and during major energy generation/absorption phases of the gait cycle would reliably discriminate age-related degeneration during unobstructed walking. The gaits of 24 healthy adults (12 young and 12 elderly) were analysed using the PEAK Motus motion analysis system. The elderly participants showed significantly greater single (60.3% versus 62.3%, p < 0.01) and double ( p < 0.05) support times, reduced knee flexion (47.7° versus 43.0°, p < 0.05) and ankle plantarflexion (16.8° compared to 3.3°, p = 0.053) at toe off, reduced knee flexion during push-off and reduced ankle dorsiflexion (16.8° compared to 22.0°, p < 0.05) during the swing phase. The plantarflexing ankle joint motion during the stance to swing phase transition (A₂) for the young group (31.3°) was about twice ( p < 0.05) that of the elderly (16.9°). Reduced knee extension range of motion suggests that the elderly favoured a flexed-knee gait to assist in weight acceptance. Reduced dorsiflexion by the elderly in the swing phase implies greater risk of toe contact with obstacles. Overall, the results suggest that joint angle measures at critical events/phases in the gait cycle provide a useful indication of age-related degeneration in the control of lower limb trajectories during unobstructed walking.     

Knee joint dysfunctions that influence gait in cerebrovascular injury

INTRODUCTION: There is still no consensus among different specialists on the subject of kinematic variation during the hemiparetic gait, including the main changes that take place during the gait cycle and whether the gait velocity changes the patterns of joint mobility. One of the most frequently discussed joints is the knee. OBJECTIVES: This study aims to evaluate the variables found in the angular kinematics of knee joint, and to describe the alterations found in the hemiparetic gait resulting from cerebrovascular injury. METHODS: This study included 66 adult patients of both genders with a diagnosis of either right or left hemiparesis resulting from ischemic cerebrovascular injury. All the participants underwent three-dimensional gait evaluation, an the angular kinematics of the joint knee were selected for analysis. RESULTS: The results were distributed into four groups formed based on the median of the gait speed and the side of hemiparesis. CONCLUSIONS: The relevant clinical characteristics included the important mechanisms of loading response in the stance, knee hyperextension in single stance, and reduction of the peak flexion and movement amplitude of the knee in the swing phase. These mechanisms should be taken into account when choosing the best treatment. We believe that the findings presented here may aid in preventing the occurrence of the problems found, and also in identifying the origin of these problems.     

Generation,absorption, and transfer of mechanical energy during walking in children

The purpose of this study was to characterize the manner in which net joint moments and non-muscular forces generate, absorb, and transfer mechanical energy during walking in able-bodied children. Standard gait data from seven healthy subjects between 6 and 17 years of age were combined with a dynamic model of the whole body to perform a power analysis based on induced acceleration techniques. These data were used to determine how each moment and force generates energy to, absorbs energy from, and transfers energy among the major body segments. The joint moments were found to induce transfers of mechanical energy between body segments that generally exceeded the magnitudes of energy generation and absorption. The amount of energy transferred by gravitational and velocity-dependent forces was considerably less than for the joint moments. The hip and ankle joint moments had relatively simple power patterns that tended to oppose each other, particularly over the stance phase. The knee joint moment had a more complex power pattern that appeared distinct from the hip and ankle moments. The general patterns of mechanical energy flow were similar to previous reports in adults. The approach described in this paper should provide a useful complement to standard clinical gait analysis procedures.