Gait Model Research Articles

Two-year 3D gait outcomes following in-situ pinning or modified Dunn procedure in children with slipped capital femoral epiphysis

BackgroundSlipped Capital Femoral Epiphysis (SCFE) is femoral head slippage off the femoral neck through the physis occurring in children aged 8–16 years. Surgical intervention is required in all paediatric cases and there is no universal agreement on choice of surgical procedure. Research questionWhat are the two-year 3D gait outcomes in children with SCFE who have undergone in-situ pinning (PIN) or modified Dunn procedure (MDP) compared with normative reference values? Methods17 children with SCFE who had undergone PIN (n=7, slip severity mild to moderate) or MDP (n=10, slip severity moderate to severe) surgical procedures prospectively underwent a 3D gait analysis post-surgery (2∙0 ± 0∙5 years). Ten age-matched children were also recruited to provide normative reference values. The conventional gait model was modified to incorporate Hara hip equations and Lerner pelvic tracking methods. Gait Profile Scores, Gait Variable Scores, kinematics, kinetics and spatiotemporal data were calculated for each group. ResultsOverall gait pattern, determined by the Gait Profile Score, indicated that both SCFE groups differed from the normative reference group (PIN 6∙6 ± 2∙5⁰, MDP 6∙2 ± 2∙0⁰ vs. 4∙0 ± 1∙3⁰ norm, p<0∙05). Normalised walking speed was reduced in the MDP group (0∙40 ± 0∙04) compared to the normative reference group (0∙46 ± 0∙06; p=0∙032). SignificanceGait patterns of children with SCFE treated with PIN was more markedly altered than that of children with SCFE treated with MDP, despite having lower SCFE severity. Increased external hip rotation observed in the PIN group may be a pre-cursor for osteoarthritis in adulthood. Therefore the use of the corrective MDP which normalises hip rotation may be beneficial for reducing functional impairments.

Investigating the Effect of Motion Capture Suits on the Test–Retest Reliability of Gait Parameters

When collecting marker-based motion capture data from clinical populations, speed of collection and comfort for the participant is a priority. This could be achieved by attaching markers to motion capture Velcro suits, as opposed to the skin. This study aimed to ascertain the reliability of sagittal-plane gait parameters estimated using Plug-in Gait (PiG) and Conventional Gait Model 2 (CGM2) marker sets from data collected in Suited and Non-suited (markers placed onto skin) conditions. For ten participants, markers were placed based on PiG and CGM2 models and data captured during a 2-min treadmill walk. Trials were repeated in suited and non-suited conditions. PiG ankle flexion/extension measurements had poor/moderate reliability (Non-suited ICC = 0.531, Suited ICC = 0.435). CGM2 ankle flexion/extension measurements had good/excellent reliability (Non-suited ICC = 0.916, Suited ICC = 0.900). There were significant differences in minimal detectable change (MDC) between conditions at the ankle for PiG (Non-suited MDC = 2.32°, Suited MDC = 18.90°), but not for CGM2 (Non-suited MDC = 0.63°, Suited MDC = 0.95°). When using CGM2, knee (Non-suited ICC = 0.878, Suited ICC = 0.855) and hip (Non-suited ICC = 0.897, Suited ICC = 0.948) showed good/excellent reliability in both conditions. A motion capture suit is not a reliable solution when collecting joint angle data using the PiG model but is reliable enough to consider when using the CGM2 model.

The Shriners Children's Standard Gait Model (SCGM)

The Shriners Children's Standard Gait Model (SCGM)

Knee joint kinematics with the new conventional gait model (CGM2): A comparison of inverse versus direct kinematics

Knee joint kinematics with the new conventional gait model (CGM2): A comparison of inverse versus direct kinematics

Modelling Human-Structure Interaction in Pedestrian Bridges Using a Three-Dimensional Biomechanical Approach

Pedestrian bridges, which are essential in urban and rural infrastructures, are vulnerable to vibrations induced by pedestrian traffic owing to their low mass, stiffness, and damping. This paper presents a novel predictive model of Human-Structure Interaction (HSI) that integrates a three-dimensional biomechanical model of the human body, and a pedestrian bridge represented as a simply supported Euler-Bernoulli beam. Using inverse dynamics, the human model accurately captures three-dimensional gait and its interaction with structural vibrations. The results show that this approach provides precise estimates of human gait kinematics and kinetics, as well as the bridge response under pedestrian loads. The incorporation of a three-dimensional human gait model reflects the changes induced by bridge vibrations, providing a robust tool for evaluating and improving the effect of structural vibrations on the properties and gait patterns.

The effect of impaired unilateral ankle propulsion on contralateral knee joint loading

BackgroundImpairments in unilateral ankle propulsion may result from restriction by an external device or pathology such as lower limb amputation. Models of gait suggest this reduction may lead to increased collisional force on the contralateral side, potentially increasing force through the knee and increasing the risk of knee pain or osteoarthritis. Research questionHow do restrictions in unilateral ankle propulsive force affect contralateral knee joint loading in otherwise healthy individuals? Methods18 individuals without impairment walked on a treadmill at 1.5 m/s for two conditions: one free of restrictions, and one where a randomized limb’s ankle propulsive force was restricted using an off-the-shelf ankle-foot orthosis (AFO). Ankle propulsive power, lower extremity joint work, and ground reaction force variables were calculated for the final 3 gait cycles of each condition. Tibiofemoral joint contact force (TJCF) for the limb contralateral to the AFO was calculated through a standard OpenSim workflow utilizing the gait2392 model. Intra-limb pair-wise comparisons were made between conditions. ResultsCompared to walking unrestricted, the limb wearing the AFO demonstrated a significant reduction in peak ankle propulsive power and positive ankle work by approximately 50 % each (p<0.01). With ankle restriction, the ipsilateral knee significantly increased positive work (p<0.01). The overall propulsion produced by that limb did not change between conditions, demonstrated by a lack of change in anterior ground reaction force impulse (p=0.11). The knee of the limb contralateral to the AFO did not display differences in any TJCF variable between conditions (all p>0.07). SignificanceThese results suggest a unilateral deficit in ankle propulsion will not increase contralateral knee joint forces in individuals who are able to use other joints of the limb to compensate for the loss of ankle function. However, further research should investigate this relationship in those who display pathologies that may prevent more proximal compensations.

REAL-TIME HIP RANGE OF MOVEMENT MEASUREMENT IN TELEREHABILITATION; COMPARISON OF HUMAN POSE ESTIMATION TOOL, PHYSIOROM, VS 3D MOTION CAPTURE SYSTEM

INTRODUCTION AND AIMS Telerehabilitation is widely acknowledged, but its adoption in musculoskeletal cohorts has been restricted due to challenges in accurately measuring objective parameters such as range of movement (ROM). This research assesses the accuracy of a human pose estimation tool utilising two-dimensional (2D) video (PhysioROM, Coviu) for evaluating active hip flexion and abduction ROM during common rehabilitation exercises, compared to three-dimensional (3D) motion capture. METHODS Fifty participants (18 to 80 years) were recruited, each performing three common hip movements; standing hip flexion, standing hip abduction and a sit-to-stand. The motions were captured using the 12-camera, 3D Vicon motion capture system in conjunction with simultaneous 2D video, simulating a home telehealth consultation scenario. Joint kinematics were computed using either the Vicon Plug-in Gait model (3D Vicon) or the human pose estimation tool integrated into the PhysioROM algorithm (2D PhysioROM). RESULTS No significant differences were observed in peak hip ROM measurements during the tasks undertaken. Mean peak hip flexion was 2.4° (p=1.0) less for 3D Vicon versus 2D PhysioROM in standing hip flexion, though 2.1° (p=0.46) greater during sit-to-stand movement. Hip abduction was 5.3° (p&amp;lt; 0.001) less for 3D Vicon versus 2D PhysioROM in standing hip abduction. Statistical parametric mapping revealed significant differences (p&amp;lt;0.001) in hip flexion between Vicon 3D and 2D PhysioROM for 32% of timepoints for both standing hip flexion and sit-to-stand movements, clustered around full hip extension. During standing hip abduction, significant differences (p&amp;lt;0.001) were found at 58% of timepoints clustered around neutral postures. Overall mean absolute deviation was 10.1°, 9.7° and 9.0° for hip flexion/extension, sit-to-stand, and hip abduction respectively. CONCLUSION Validity of PhysioROM to accurately measure peak hip flexion and peak hip abduction was high. PhysioROM may provide an effective method of accurately and objectively quantifying hip movement during a telerehabilitation session using 2D video.

TELEREHABILITATION ASSESSMENT OF KNEE RANGE OF MOVEMENT; COMPARISON OF HUMAN POSE ESTIMATION TOOL, PHYSIOROM, VS 3D MOTION CAPTURE SYSTEM

INTRODUCTION AND AIMS Telerehabilitation is increasingly acknowledged, though uptake remains limited by an inability to accurately undertake objective measurement. This study sought to determine the validity of a human pose estimation tool (PhysioROM, Coviu) assessed via two-dimensional (2D) video to measure active knee flexion and extension movement during common rehabilitation exercises, versus gold-standard three-dimensional (3D) motion capture. METHODS Fifty participants were recruited (aged 18 to 30), each performing three common knee rehabilitation exercises; sit-to-stand, seated and reclined active knee flexion. Movements were recorded using the 12-camera, 3D Vicon motion capture system simultaneously with 2D video simulating a home telehealth consultation. Joint kinematics were calculated using the Vicon Plug-in Gait model (3D Vicon) or the human pose estimation tool within the PhysioROM algorithm (2D PhysioROM). RESULTS Mean peak knee flexion was 3.1°, 9.9° and 24.8° (p&amp;lt;0.001) greater for 3D Vicon versus 2D PhysioROM (sit-to-stand, seated flexion and reclined flexion, respectively). For peak knee extension, Vicon 3D was 2.4° and 1.93° greater than 2D PhysioROM in sit-to-stand (p=0.020) and seated flexion (p&amp;lt; 0.001), whilst 3.6° less than PhysioROM for reclined knee flexion (p=0.030). Statistical parametric mapping revealed significant differences between Vicon 3D and PhysioROM for 71% and 42% of timepoints (p&amp;lt;0.001) for seated and reclined movements, clustered around full knee flexion. Significant differences were also found at an additional 37% (p&amp;lt;0.001) of timepoints clustered around knee extension for reclined postures. Overall mean absolute deviation was 8.7°, 7.6° and 16.5° for sit-to-stand, seated flexion and reclined flexion, respectively. CONCLUSION Validity of PhysioROM to accurately measure knee flexion was high, less so in extension, during sit-to stand movements in a seated posture. Measurement in a reclined position were less accurate. PhysioROM may provide an effective method of accurately and objectively quantifying knee movement during a telerehabilitation session using 2D video.

Effects of different step lengths at a preferred walking speed on forefoot, midfoot, and hindfoot motion in healthy young adults

Hindfoot, midfoot, and forefoot motion during the stance phase of walking provide insights into the forward progression of the body over the feet via the rocker mechanisms. These segmental motions are affected by walking speed. Increases in walking speed are accomplished by increasing step length and cadence. It is unknown if taking short, medium, and long steps at the same speed would increase hindfoot, midfoot, and forefoot motion similarly to walking speed. We examined effects of different step lengths at the same preferred walking speed on peak forefoot, midfoot, and hindfoot motions related to the foot rockers. Twelve young healthy adults completed five walking trials under three step length conditions in a random order as feet and lower extremity motion were measured via marker positions for the combined Oxford foot and conventional gait models. Peak hindfoot, midfoot, and forefoot joint angles indicating heel, ankle, and forefoot rockers were identified. When walking at the same preferred speed with increase in step length, there were increases in peak hindfoot-tibia plantarflexion angle (p < 0.001; ηp2 = 0.76) in early stance associated with the heel rocker and peak hindfoot-tibia dorsiflexion angle (p = 0.016; ηp2 = 0.39) in midstance associated with ankle rocker. In late stance, the peak hindfoot-tibia plantarflexion angle, forefoot-hindfoot angle, and forefoot-hallux dorsiflexion angle indicating forefoot rocker motion also increased with step length (p < 0.01). When foot kinematics are compared across different individuals or the same individual across different sessions, researchers and clinicians should consider the influence of step length as a contributor to differences in foot kinematics observed.

Current practices in clinical gait analysis in Europe: A comprehensive survey-based study from the European society for movement analysis in adults and children (ESMAC) standard initiative

BackgroundClinical gait analysis (CGA) is a systematic approach to comprehensively evaluate gait patterns, quantify impairments, plan targeted interventions, and evaluate the impact of interventions. However, international standards for CGA are currently lacking, resulting in various national initiatives. Standards are important to ensure safe and effective healthcare practices and to enable evidence-based clinical decision-making, facilitating interoperability, and reimbursement under national healthcare policies. Collaborative clinical and research work between European countries would benefit from common standards. Research objectiveThis study aimed to review the current laboratory practices for CGA in Europe. MethodsA comprehensive survey was conducted by the European Society for Movement Analysis in Adults and Children (ESMAC), in close collaboration with the European national societies. The survey involved 97 gait laboratories across 16 countries. The survey assessed several aspects related to CGA, including equipment used, data collection, processing, and reporting methods. ResultsThere was a consensus between laboratories concerning the data collected during CGA. The Conventional Gait Model (CGM) was the most used biomechanical model for calculating kinematics and kinetics. Respondents also reported the use of video recording, 3D motion capture systems, force plates, and surface electromyography. While there was a consensus on the reporting of CGA data, variations were reported in training, documentation, data preprocessing and equipment maintenance practices. SignificanceThe findings of this study will serve as a foundation for the development of standardized guidelines for CGA in Europe.

The primary stability of a cementless PEEK femoral component is sensitive to BMI: A population-based FE study

The use of polyetheretherketone (PEEK) for cementless femoral total knee arthroplasty (TKA) components is of interest due to several potential advantages, e.g. the use in patients with metal hypersensitivity. Additionally, the stiffness of PEEK closer resembles the stiffness of bone, and therefore, peri-prosthetic stress-shielding may be avoided. When introducing a new implant material for cementless TKA designs, it is important to study its effect on the primary fixation, which is required for the long-term fixation. Finite element (FE) studies can be used to study the effect of PEEK as implant material on the primary fixation, which may be dependent on patient factors such as age, gender and body weight index (BMI). Therefore, the research objectives of this study were to investigate the effect of PEEK vs cobalt-chrome (CoCr) and patient characteristics on the primary fixation of a cementless femoral component. 280 FE models of 70 femora were created with varying implant material and gait and squat activity. Overall, the PEEK models generated larger peak micromotions than the CoCr models. Distinct differences were seen in the micromotion distributions between the PEEK and CoCr models for both the gait and squat models. The micromotions of all femoral models significantly increased with BMI. Neither gender nor age of the patients had a significant effect on the micromotions. This population study gives insights into the primary fixation of a cementless femoral component in a cohort of FE models with varying implant material and patient characteristics.

Multi-gait snake robot for inspecting inner wall of a pipeline

In the field of pipeline inner wall inspection, the snake robot demonstrates significant advantages over other inspection methods. While a simple traveling wave or meandering motion will suffice for inspecting the inner wall of small-diameter pipes, comprehensively and meticulously inspecting the inner wall of large-diameter pipes requires the snake robot to adopt a helical gait that closely adheres to the inner wall. Our review of existing literature indicates that most research and development on the helical gait of snake robots has focused on the outer surface of cylinders, with very few studies dedicated to developing a helical gait specifically for the inspection of the inner wall of pipes. Therefore, in this study, we propose a helical gait that is suitable for the inner wall of pipes and meets the requirements of gas pipeline engineering. The helical gait is designed using the backbone curve method. First, we create a mathematical model for a circular helix curve with constant curvature and torsion, ensuring it is applicable to a snake robot prototype in a laboratory environment. Subsequently, we calculate the joint angles required for two conical spiral curves with variable curvature and torsion, establish a new model, and define the physical significance of the specific parameters. To ensure the feasibility of the proposed gait, we conduct experiments involving meandering and traveling wave motions to verify the communication and control between the host computer and the snake robot. Building upon this foundation, we further validate the mathematical model of the complex helical motion gait through simulation experiments. Our findings provide a theoretical basis for realizing helical movement with a real snake robot.

Motion acquisition of gait characteristics one week after total hip arthroplasty: a factor analysis

IntroductionClinical gait analysis can be used to evaluate the recovery process of patients undergoing total hip arthroplasty (THA). The postoperative walking patterns of these patients can be significantly influenced by the choice of surgical approach, as each procedure alters distinct anatomical structures. The aim of this study is twofold. The first objective is to develop a gait model to describe the change in ambulation one week after THA. The secondary goal is to describe the differences associated with the surgical approach.Materials and methodsThirty-six patients undergoing THA with lateral (n = 9), anterior (n = 15), and posterior (n = 12) approaches were included in the study. Walking before and 7 days after surgery was recorded using a markerless motion capture system. Exploratory Factor Analysis (EFA), a data reduction technique, condensed 21 spatiotemporal gait parameters to a smaller set of dominant variables. The EFA-derived gait domains were utilized to study post-surgical gait variations and to compare the post-surgical gait among the three groups.ResultsFour distinct gait domains were identified. The most pronounced variation one week after surgery is in the Rhythm (gait cycle time: +32.9%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$+32.9\\mathrm{\\%}$$\\end{document}), followed by Postural control (step width: +27.0%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$+27.0\\mathrm{\\%}$$\\end{document}), Phases (stance time: +11.0%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$+11.0\\%$$\\end{document}), and Pace (stride length: − 9.3%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$9.3\\%$$\\end{document}). In postsurgical walking, Phases is statistically significantly different in patients operated with the posterior approach compared to lateral (p-value = 0.017) and anterior (p-value = 0.002) approaches. Furthermore, stance time in the posterior approach group is significantly lower than in healthy individuals (p-value < 0.001).ConclusionsThis study identified a four-component gait model specific to THA patients. The results showed that patients after THA have longer stride time but shorter stride length, wider base of support, and longer stance time, although the posterior group had a statistically significant shorter stance time than the others. The findings of this research have the potential to simplify the reporting of gait outcomes, reduce redundancy, and inform targeted interventions in regards to specific gait domains.

Gait Recognition and Assistance Parameter Prediction Determination Based on Kinematic Information Measured by Inertial Measurement Units.

The gait recognition of exoskeletons includes motion recognition and gait phase recognition under various road conditions. The recognition of gait phase is a prerequisite for predicting exoskeleton assistance time. The estimation of real-time assistance time is crucial for the safety and accurate control of lower-limb exoskeletons. To solve the problem of predicting exoskeleton assistance time, this paper proposes a gait recognition model based on inertial measurement units that combines the real-time motion state recognition of support vector machines and phase recognition of long short-term memory networks. A recognition validation experiment was conducted on 30 subjects to determine the reliability of the gait recognition model. The results showed that the accuracy of motion state and gait phase were 99.98% and 98.26%, respectively. Based on the proposed SVM-LSTM gait model, exoskeleton assistance time was predicted. A test was conducted on 10 subjects, and the results showed that using assistive therapy based on exercise status and gait stage can significantly improve gait movement and reduce metabolic costs by an average of more than 10%.

The Shriners Children’s Gait Model (SCGM)

The Shriners Children’s Gait Model (SCGM)

The Effect of Patient-Related Factors on the Primary Fixation of PEEK and Titanium Tibial Components: A Population-Based FE Study.

Polyetheretherketone (PEEK) is of interest as implant material for cementless tibial total knee arthroplasty (TKA) components due to its potential advantages. One main advantage is that the stiffness of PEEK closely resembles the stiffness of bone, potentially avoiding peri-prosthetic stress-shielding. When introducing a new implant material for cementless TKA designs, it is essential to study its effect on the primary fixation. The primary fixation may be influenced by patient factors such as age, gender, and body mass index (BMI). Therefore, the research objectives of this finite element (FE) study were to investigate the effect of material (PEEK vs. titanium) and patient characteristics on the primary fixation (i.e., micromotions) of a cementless tibial tray component. A total of 296 FE models of 74 tibiae were created with either PEEK or titanium material properties, under gait and squat loading conditions. Overall, the PEEK models generated larger peak micromotions than the titanium models. Differences were seen in the micromotion distributions between the PEEK and titanium models for both the gait and squat models. The micromotions of all tibial models significantly increased with BMI, while gender and age did not influence micromotions.

State identification for a class of uncertain switched systems by differential neural networks

ABSTRACT This paper presents a non-parametric identification scheme for a class of uncertain switched nonlinear systems based on continuous-time neural networks. This scheme is based on a continuous neural network identifier. This adaptive identifier guaranteed the convergence of the identification errors to a small vicinity of the origin. The convergence of the identification error was determined by the Lyapunov theory supported by a practical stability variation for switched systems. The same stability analysis generated the learning laws that adjust the identifier structure. The upper bound of the convergence region was characterized in terms of uncertainties and noises affecting the switched system. A second finite-time convergence learning law was also developed to describe an alternative way of forcing the identification error’s stability. The study presented in this paper described a formal technique for analysing the application of adaptive identifiers based on continuous neural networks for uncertain switched systems. The identifier was tested for two basic problems: a simple mechanical system and a switched representation of the human gait model. In both cases, accurate results for the identification problem were achieved.

Height-Adaptive Human Gait Model Through Radar-Driven Pipeline With Two Co-Located mmWave MIMO Radars

Height-Adaptive Human Gait Model Through Radar-Driven Pipeline With Two Co-Located mmWave MIMO Radars

Modeling the Heterogeneity of Post-Stroke Gait Control in Free-Living Environments Using a Personalized Causal Network.

Post-stroke gait control is a complex, often fail to account for the heterogeneity and continuity of gait in existing gait models. Precisely evaluating gait speed adjustability and gait instability in free-living environments is important to understand how individuals with post-stroke gait dysfunction approach diverse environments and contexts. This study aimed to explore individual causal interactions in the free-living gait control of persons with stroke. To this end, fifty persons with stroke wore an accelerometer on the fifth lumbar vertebra (L5) for 24 h in a free-living environment. Individually directed acyclic graphs (DAGs) were generated based on the spatiotemporal gait parameters at contemporaneous and temporal points calculated from the acceleration data. Spectral clustering and Bayesian model comparison were used to characterize the DAGs. Finally, the DAG patterns were interpreted via Bayesian logistic analysis. Spectral clustering identified three optimal clusters from the DAGs. Cluster 1 included persons with moderate stroke who showed high gait asymmetry and gait instability and primarily adjusted gait speed based on cadence. Cluster 2 included individuals with mild stroke who primarily adjusted their gait speed based on step length. Cluster 3 comprised individuals with mild stroke who primarily adjusted their gait speed based on both step length and cadence. These three clusters could be accurately classified based on four variables: Ashman's D for step velocity, Fugl-Meyer Assessment, step time asymmetry, and step length. The diverse DAG patterns of gait control identified suggest the heterogeneity of gait patterns and the functional diversity of persons with stroke. Understanding the theoretical interactions between gait functions will provide a foundation for highly tailored rehabilitation.

A Novel 3D Gait Model for Subject Identification Robust against Carrying and Dressing Variations

A Novel 3D Gait Model for Subject Identification Robust against Carrying and Dressing Variations