The influence of frontal alignment in the advanced reciprocating gait orthosis on energy cost and crutch force requirements during paraplegic gait

Reduction of energy cost and upper body load during paraplegic walking is considered to be an important criterion in future developments of walking systems. A high energy cost limits the maximum walking distance in the current devices, whereas wrist and shoulder pathology can deteriorate because of the high upper body load. A change in alignment of the mechanical brace in the frontal plane, i.e. abduction, can contribute to a more efficient gait pattern with sufficient foot clearance with less pelvic lateral sway. A decrease in pelvic lateral sway after aligning in abduction results in a shift of the centre of mass to the swing leg crutch which may result in a decrease in required crutch force on stance side to maintain foot clearance. Five paraplegic subjects were provided with a standard Advanced Reciprocating Gait Orthosis (ARGO) and an ARGO aligned in 4 different degrees of abduction (0°, 3°, 6° and 9°). After determining an optimal abduction angle for each of the subjects, a cross over design was used to compare the ARGO with the individually optimised abducted orthosis. An abduction angle between 0° and 3° was chosen as optimal abduction angle. Subjects were not able to walk satisfactory with abduction angles 6° and 9°. A significant reduction in crutch peak force on stance side was found (approx. 12% , p < 0.01) in the abducted orthosis. Reduction in crutch force time integral (15%) as well as crutch peak force on swing side (5%) was not significant. No differences in oxygen uptake as well as oxygen cost was found. We concluded that an abduction angle between 0° and 3° is beneficial with respect to upper boHy load, whereas energy requirements did not change

A review of the effectiveness of lower limb orthoses used in cerebral palsy

To produce this review, a systematic literature search was conducted for relevant articles published in the period between the date of the previous ISPO consensus conference report on cerebral palsy (1994) and April 2008. The search terms were 'cerebral and pals* (palsy, palsies), 'hemiplegia', 'diplegia', 'orthos*' (orthoses, orthosis) orthot* (orthotic, orthotics), brace or AFO

Joint Trajectory Generation and High-level Control for Patient-tailored Robotic Gait Rehabilitation

This dissertation presents a group of novel methods for robot-based gait rehabilitation which were developed aiming to offer more individualized therapies based on the specific condition of each patient, as well as to improve the overall rehabilitation experience for both patient and therapist. A novel methodology for gait pattern generation is proposed, which offers estimated hip and knee joint trajectories corresponding to healthy walking, and allows the therapist to graphically adapt the reference trajectories in order to fit better the patient's needs and disabilities. Additionally, the motion controllers for the hip and knee joints, mobile platform, and pelvic mechanism of an over-ground gait rehabilitation robotic system are also presented, as well as some proposed methods for assist as needed therapy. Two robot-patient synchronization approaches are also included in this work, together with a novel algorithm for online hip trajectory adaptation developed to reduce obstructive forces applied to the patient during therapy with compliant robotic systems. Finally, a prototype graphical user interface for the therapist is also presented

A Novel Design of a Cable-driven Active Leg Exoskeleton (C-ALEX) and Gait Training with Human Subjects

Exoskeletons for gait training commonly use a rigid-linked "skeleton" which makes them heavy and bulky. Cable-driven exoskeletons eliminate the rigid-linked skeleton structure, therefore creating a lighter and more transparent design. Current cable-driven leg exoskeletons are limited to gait assistance use. This thesis presented the Cable-driven Active Leg Exoskeleton (C-ALEX) designed for gait retraining and rehabilitation. Benefited from the cable-driven design, C-ALEX has minimal weight and inertia (4.7 kg) and allows all the degrees-of-freedom (DoF) of the leg of the user. C-ALEX uses an assist-as-needed (AAN) controller to train the user to walk in a new gait pattern. A preliminary design of C-ALEX was first presented, and an experiment was done with this preliminary design to study the effectiveness of the AAN controller. The result on six healthy subjects showed that the subjects were able to follow a new gait pattern significantly more accurately with the help of the AAN controller. After this experiment, C-ALEX was redesigned to improve its functionality. The improved design of C-ALEX is lighter, has more DoFs and larger range-of-motion. The controller of the improved design improved the continuity of the generated cable tensions and added the function to estimate the phase of the gait of the user in real-time. With the improved design of C-ALEX, an experiment was performed to study the effect of the weight and inertia of an exoskeleton on the gait of the user. C-ALEX was used to simulate exoskeletons with different levels of weight and inertia by adding extra mass and change the weight compensation level. The result on ten subjects showed that adding extra mass increased step length and reduced knee flexion. Compensating the weight of the mass partially restored the knee flexion but not the step length, implying that the inertia of the mass is responsible for the change. This study showed the distinctive effect of weight and inertia on gait and demonstrated the benefit of a lightweight exoskeleton. C-ALEX was designed for gait training and rehabilitation, and its training effectiveness was studied in nine healthy subjects and a stroke patient. The healthy subjects trained with C-ALEX to walk in a new gait pattern with 30% increase in step height for 40 min. After the training, the subjects were able to closely repeat the trained gait pattern without C-ALEX, and the step height of the subjects increased significantly. A stroke patient also tested C-ALEX for 40 minutes and showed short-term improvements in step length, step height, and knee flexion after training. The result showed the effectiveness of C-ALEX in gait training and its potential to be used in stroke rehabilitation

Development of a New Experimental Protocol for Analysing the Race-walking Technique Based on Kinematic and Dynamic Parameters

Abstract This paper describes a new motion analysis protocol for race-walking. The protocol has been tested under laboratory conditions on a real athlete of the Italian national race-walking team. The experimental setup included a motion capture system and a force platform to record both kinematic and dynamic aspects of the athletic action. Thus, any infringement of the rules can be detected, based on the measure of knee flexion-extension and the loss of ground contact. The biomechanical efficiency can be determined from the joint angles and the temporal components of gait. The results of experiments show that the protocol can be a valuable tool to assist athletes and trainers in improving race-walking technique

퇴행성 슬 관절염의 객관적 평가를 위한 기계학습 기반의 보행 데이터 분석 연구

학위논문 (박사) -- 서울대학교 대학원 : 공과대학 협동과정 바이오엔지니어링전공, 2020. 8. 김희찬.Osteoarthritis (OA) is a disease that affects above 30% of the elderly population aged 60 years and older. Western Ontario and McMaster Osteoarthritis (WOMAC) and radiographic-based Kellgren–Lawrence (KL) grade methods are currently used to evaluate the severity of knee osteoarthritis (KOA). However, the WOMAC is a subjective method which cannot be performed to certain patients, and is not suitable for tracking changes in severity over time. KL grade requires highly trained experts and is a time consuming process. This dissertation hypothesized that objective and biomechanical gait data can supplement unmet needs of current gold standard. It was hypothesized that specific features from gait data would reflect the severity of KOA. Therefore, this study aims to identify key gait features associated with the severity of KOA and provide a new objective and explainable evaluation method for KOA based on gait analysis. Features were extracted from the gait signal and an automated severity evaluation model was designed based on machine learning technique for WOMAC severity evaluation model. To develop an automated severity evaluation algorithm for KL grade, features were extracted from the plain radiography image using deep learning network, and machine learning was applied to select features from the gait data. Both image and gait features were used to develop a machine learning algorithm for KL grade evaluation. The evaluation algorithm for WOMAC and KL grade showed a correlation of 0.741 and an accuracy of 75.2% with gold standard method, respectively. This dissertation proposed a new evaluation method for KOA and showed the clinical utility of the gait data application that was limited in clinical practice due to the complexity of the signal.퇴행성 관절염은 60세 이상의 노인 인구 약 30%에서 발병하는 질병이다. 현재 퇴행성 슬 관절염의 진단은 Western Ontario and McMaster Osteoarthritis (WOMAC) 방법과 방사선 촬영 기반의 Kellgren–Lawrence (KL) grade 방법이 사용되고 있다. 그러나 WOMAC 환자의 주관적인 판단을 토대로 중증도를 정량화하는 방법이어서 일부 환자들에게 적용이 불가능하고, 수술 후의 중증도를 반영하지 못한다는 단점이 있다. KL grade은 고도로 훈련된 전문가를 필요로 하며, 정확한 진단을 위하여서는 많은 시간을 필요로 한다. 반면 보행 신호는 환자의 보행에 따른 객관적인 생체 역학 신호를 제공하며, 보행이 가능한 모든 사람에게 적용이 가능하며, 주기적인 추적 관찰에 용의하다. 따라서 본 연구는 보행 신호를 이용하여 객관적이며, 결과에 대한 생체 역학적 이유를 알 수 있는 퇴행성 슬 관절염의 새로운 분석 방법을 제시함에 있다. 먼저 자동으로 WOMAC 방법을 진단하기 위해 보행신호에서 특징들을 추출하고 기계학습 기법을 이용하여 평가하는 모델을 개발하였다. 또한 KL grade 방법을 평가하기 위해 방사선 영상에서 딥러닝 알고리즘으로 추출한 특징들과 보행신호에서 추출한 특징들을 기계학습 기법을 이용하였다. 제안하는 퇴행성 슬 관절염의 평가 방법은 WOMAC 및 KL grade 방법과 각각 상관관계 0.741, 정확도 75.2%를 보였다. 본 연구는 퇴행성 슬 관절염의 새로운 평가 방법을 제시하였으며, 신호의 복잡성으로 인하여 임상에서 사용되지 못했던 보행 신호의 임상적 활용성을 보여주었다.1. Introduction 1 1.1. Knee Osteoarthritis 2 1.2. Severity Evaluation of Knee Osteoarthritis 4 1.2.1. Symptomatic Severity evaluation 4 1.2.2. Structural Severity evaluation 5 1.3. Unmet Clinical Needs 7 1.4. Gait analysis and KOA 8 1.5. Thesis objectives 12 2. Symptomatic Severity of Knee Osteoarthritis 14 2.1. Introduction 15 2.2. Methods 18 2.2.1. Participants 18 2.2.2. Gait Data Collection 20 2.2.3. Statistical Analysis and WOMAC Estimation Model 21 2.3. Results 25 2.4. Discussion 34 2.5. Conclusion 41 3. Structural Severity of Knee Osteoarthritis 42 3.1. Introduction 43 3.2. Methods 49 3.2.1. Participants 49 3.2.2. Gait Data Collection 52 3.2.3. Radiographic Assessment 53 3.2.4. Feature Extraction and Classification 54 3.3. Results 62 3.3.1. Feature Analysis 62 3.3.2. Deep Learning Approach Based on Radiographic Images 72 3.3.3. Proposed Model Based on Gait Data and Radiographic Images 74 3.4. Discussion 76 3.5. Conclusion 83 4. Conclusion 84 4.1. Thesis Summary and Contributions 85 4.2. Future Direction 87 Bibliography 89 Abstract in Korean 98Docto

Doctor of Philosophy

dissertationOver the years, the soldier's load has increased; weapon system improvements and the need for increased protection and firepower require individuals to carry more equipment. Although the current army field manual provides recommended guidelines for a soldier's load per operation, soldiers typically carry loads exceeding the recommended guidelines. The overall effect of these heavy loads on the soldier's body and the impact on the soldier's performance is still uncertain. In this study, we analyzed the existing and proposed Korean army backpack designs and determined how each of the designs impacts stress on the soldier's upper body. Twenty healthy male subjects participated in this study. Subjects were selected from among University of Utah students who have not experienced or have fully recovered from discomfort, injuries, or disorders that could affect normal gait. Each trial had 3 repetitions. The independent variables being controlled were surface types and orientations, backpack types and loads, and marching speed. While each subject walked on the tracks with or without a backpack, threedimensional motion data and analog data (EMG, load cell) were collected with 16 Optitrack V100:R2 cameras, AMASS software, and LabVIEW. The captured data were then processed with Visual3D, Vicon Nexus, and MATLAB software. Using inverse dynamics and recorded erector spinae electromyography (EMG) data, force on the L5/S1 disc was estimated using the proposed biomechanical model. Shoulder force data was measured from customized load cells integrated into the shoulder straps of the backpacks. Upper body segments exhibited greater deviations from neutral positions (i.e., greater thorax flexion, greater thorax lateral flexion, and more pelvic anterior tilt) when carrying a backpack than under normal walking conditions. These deviations resulted in increased shoulder tension, which, in turn, increased compressive and shear forces on the L5/S1 disc

The effect of altered running form on overuse injury risk factors

Running is a popular sport with more competitive participants every year. This rise in popularity has contributed to a rise in prevalence of overuse injuries such as patellofemoral pain, iliotibial band syndrome, and tibial stress fractures. While it is widely believed by coaches and runners that running form, which includes core control and position, plays an important role in injury prevention, little quantitative data exists to support these claims. The impact of altering running form on biomechanical loadings, as well as the best method to achieve changes, is unknown. Previous studies have explored the association of biomechanical loadings with particular overuse injuries, but the impact of core stability and control on those loadings is unknown. Pelvic tilt is a factor in core control and can indicate weakness or abnormal muscle activation in the trunk, and so may also play a role in changing loadings during motion. To explore the association between pelvic tilt and biomechanical loadings associated with running overuse injuries, and to test the effects of one type of technique instruction for running biomechanics, human subjects performed running tasks. Via motion and force capture technology, the gait cycle and loadings of the subjects were collected as they performed normal running and altered pelvic tilt running tasks. Loadings were calculated and normalized by body mass. Subjects were found to have the ability to change pelvic tilt in the anterior or posterior direction. Hip adduction moment and impulse were reduced when subjects altered running form by increasing anterior tilt, and these reductions may correlate to a decreased risk for iliotibial band syndrome. Further study and confirmation of this data is recommended. Advisor: Ajit ChaudhariNFL Charities FoundationA one-year embargo was granted for this item

Biomechanical models of the lower limb and pelvis, for female human gait in regular and overload conditions related to pregnancy.

Doutoramento em Motricidade Humana na especialidade de BiomecânicaA gravidez é uma fase especial da vida , considerando as adaptações morfológicas, fisiológicas, biomecânicas e hormonais vivenciadas pelas mulheres durante cerca de 40 semanas e no período pós-parto, podendo modificar o padrão de marcha e contribuir para uma sobrecarga no sistema músculo-esquelético, causando dor nos membros inferiores, bacia e zona lombar. Os objetivos do presente trabalho foram: 1) analisar a marcha de mulheres grávidas no segundo trimestre; 2) comparar as adaptações biomecânicas da marcha, entre as mulheres grávidas no segundo trimestre, mulheres não grávidas e mulheres com condições de sobrecarga artificiais; 3) analisar modelos biomecânicos com quatro set ups diferentes de análise; e, 4) analisar um modelo de contacto que determina a força vertical de reação do apoio. Os resultados demonstraram que as mulheres grávidas têm uma padrão de marcha similar ao normal. Observou-se que o ganho do peso no tronco aumenta o tempo das fases de apoio e de duplo apoio, quer nas mulheres grávidas quer nas mulheres com carga adicional. A resposta ao momento externo flexor da anca está relacionada com maior atividade dos extensores para suportar a carga anterior do tronco na direção da translação do centro de massa. Nas mulheres grávidas, o modelo universal-revolução-esférica afetou mais as variáveis cinemáticas quando comparado com o modelo de juntas com seis graus de liberdade. O modelo de contacto entre o pé e o solo, sobrestimou as forças verticais de reação. O aumento da massa do pé, devido ao inchaço consequente da gravidez, reduz a rigidez durante a fase de apoio. Os resultados do presente trabalho serão úteis para promover a investigação biomecânica do padrão de marcha durante a gravidez.FCT - Fundação para Ciência e a Tecnologi

Subjects with hip osteoarthritis show distinctive patterns of trunk movements during gait-a body-fixed-sensor based analysis

<p>Abstract</p> <p>Background</p> <p>Compensatory trunk movements during gait, such as a Duchenne limp, are observed frequently in subjects with osteoarthritis of the hip, yet angular trunk movements are seldom included in clinical gait assessments. Hence, the objective of this study was to quantify compensatory trunk movements during gait in subjects with hip osteoarthritis, outside a gait laboratory, using a body-fixed-sensor based gait analysis. Frontal plane angular movements of the pelvis and thorax and spatiotemporal parameters of persons who showed a Duchenne limp during gait were compared to healthy subjects and persons without a Duchenne limp.</p> <p>Methods</p> <p>A Body-fixed-sensor based gait analysis approach was used. Two body-fixed sensors were positioned at the dorsal side of the pelvis and on the upper thorax. Peak-to-peak frontal plane range of motion (ROM) and spatiotemporal parameters (walking speed, step length and cadence) of persons with a Duchenne limp during gait were compared to healthy subjects and persons without a Duchenne limp. Participants were instructed to walk at a self-selected low, preferred and high speed along a hospital corridor. Generalized estimating equations (GEE) analyses were used to assess group differences between persons with a Duchenne limp, without a Duchenne limp and healthy subjects.</p> <p>Results</p> <p>Persons with a Duchenne limp showed a significantly larger thoracic ROM during walking compared to healthy subjects and to persons without a Duchenne limp. In both groups of persons with hip osteoarthritis, pelvic ROM was lower than in healthy subjects. This difference however only reached significance in persons without a Duchenne limp. The ratio of thoracic ROM relative to pelvic ROM revealed distinct differences in trunk movement patterns. Persons with hip osteoarthritis walked at a significantly lower speed compared to healthy subjects. No differences in step length and cadence were found between patients and healthy subjects, after correction for differences in walking speed.</p> <p>Conclusions</p> <p>Distinctive patterns of frontal plane angular trunk movements during gait could be objectively quantified in healthy subjects and in persons with hip osteoarthritis using a body-fixed-sensor based gait analysis approach. Therefore, frontal plane angular trunk movements should be included in clinical gait assessments of persons with hip osteoarthritis.</p