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The body weight support rehabilitation training system has now become an important treatment method for the rehabilitation of lower limb motor dysfunction. In this paper, a pelvic brace body weight support rehabilitation system is proposed, which follows the center of mass height (CoMH) of the human body. It aims to address the problems that the existing pelvic brace body weight support rehabilitation system with constant impedance provides a fixed motion trajectory for the pelvic mechanism during the rehabilitation training and that the patients have low participation in rehabilitation training. The system collectes human lower limb motion information through inertial measurement unit and predicts CoMH through artificial neural network to realize the tracking control of pelvic brace height. The proposed CoMH model was tested through rehabilitation training of hemiplegic patients. The results showed that the range of motion of the hip and knee joints on the affected side of the patient was improved by 25.0% and 31.4%, respectively, and the ratio of swing phase to support phase on the affected side was closer to that of the gait phase on the healthy side, as opposed to the traditional body weight support rehabilitation training model with fixed motion trajectory of pelvic brace. The motion trajectory of the pelvic brace in CoMH mode depends on the current state of the trainer so as to realize the walking training guided by active movement on the healthy side of hemiplegia patients. The strategy of dynamically adjustment of body weight support is more helpful to improve the efficiency of walking rehabilitation training.
Subject(s)
Humans , Biomechanical Phenomena , Gait , Hemiplegia , Pelvis , Range of Motion, Articular , Stroke Rehabilitation , WalkingABSTRACT
Objective To analyze human gait stability by acceleration signal at the head and lumbar under different walking conditions, and make comparison with parameters by the traditional COM (center of mass)-COP(center of pressure) method, so as to discuss the reliability of applying wearable sensors to analyze human gait stability. Methods The harmonic ratio (HR) parameter at the head and lumbar based on acceleration signal was applied to analyze gait stability of 18 healthy young adults under 3 walking conditions (footwear normal walking, barefoot normal walking and barefoot walking at different velocities), and the results were compared with the assessment results from the COM-COP method. Results Walking at normal velocity was most stable, with the maximum HR parameter. Compared with footwear walking, HR parameters were significantly decreased (P＜0.05) during barefoot walking, indicating that gait stability was reduced. The results were consistent with the assessment results from the COM-COP method. Considering the factors of walking velocity and footwear, the gait stability parameters obtained by the two methods showed a significant negative linear correlation (R2＞0.50). Lumbar HR parameter and COM-COP parameters showed a stronger linear correlation (R2＞0.65). Conclusions The application of acceleration signal-based analysis algorithm could effectively and reliably evaluate the stability of human gait, and acceleration at the lumbar was more sensitive than the head signal for analyzing gait stability.
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The aim of this study was to evaluate the influence of balance on the spatiotemporal features, lower-limb kinematics, and center of mass (COM) of the non-faller elderly during walking. In this study, 20 healthy elderly women (age, 76.2 ± 5.6 years; height, 150.1 ± 3.2 cm; weight, 55.8 ± 9.0 kg) were enrolled. Based on the Berg balance scale (BBS), the elderly were classified into two groups: poor balance (PB; BBS scores 0.05). The ROM of the mediolateral COM was greater in PB than in GB. Hip transversal movements in the two groups were different. The impairment of the lateral balance function might contribute to an increase in the incidence of fall events in the elderly with poor balance.
Subject(s)
Adult , Aged , Female , Humans , Biomechanical Phenomena , Gait , Hip , Incidence , Range of Motion, Articular , WalkingABSTRACT
Objective To compare the difference of static balance ability in different aged people, with the maximum angle of center of mass (COM) and center of pressure (COP). Methods 37 healthy people without cardiovascular and cerebrovascular diseases including 15 young people (18~40 years old), 10 middle age people (41~65 years old) and 12 old people (>65 years old) participated in this study. The maximum angle of COM-COP and the corresponding envelope areas were recorded in 4 standing posture:natural standing, close eyes stand-ing, single leg standing and single leg standing with eyes closed. Results There was no significant difference in the maximum angle of COM-COP among 3 groups in 3 states (nature standing, close eyes standing, single leg standing with eyes closed) (P>0.05), but there was significant difference in the state of single leg standing (P<0.05) between the young and the old, and the middle-aged and the old. Conclu-sion The maximum angle of COM-COP in the state of single leg standing can sensitively detect the deterioration of stability of older people. It may be a new index of static balance in clinic.
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@#Objective To compare the difference of static balance ability in different aged people, with the maximum angle of center of mass (COM) and center of pressure (COP). Methods 37 healthy people without cardiovascular and cerebrovascular diseases including 15 young people (18~40 years old), 10 middle age people (41~65 years old) and 12 old people (>65 years old) participated in this study. The maximum angle of COM-COP and the corresponding envelope areas were recorded in 4 standing posture: natural standing, close eyes standing, single leg standing and single leg standing with eyes closed. Results There was no significant difference in the maximum angle of COM-COP among 3 groups in 3 states (nature standing, close eyes standing, single leg standing with eyes closed) (P>0.05), but there was significant difference in the state of single leg standing (P<0.05) between the young and the old, and the middle-aged and the old. Conclusion The maximum angle of COM-COP in the state of single leg standing can sensitively detect the deterioration of stability of older people. It may be a new index of static balance in clinic.
ABSTRACT
Nas últimas décadas a população idosa vem aumentando rapidamente. Com esse aumento, torna-se cada vez mais relevante abordar questões relacionadas às capacidades físicas dessa população. Uma variável relevante de análise é o controle postural, o qual é importante na realização das tarefas diárias. As oscilações do centro de massa (CM), obtidas por cinemetria, e o centro de pressão (COP), obtido através da plataforma de força, fornecem variáveis que permitem análise do comportamento do controle postural. Objetivo: Verificar as correlações entre CM e COP em idosos na situação de controle de postura lestático. Materiais e métodos: Participaram do estudo 35 idosos ativos. Para obtenção do CM foi utilizado o sistema VICON de cinemetria e os dados do COP foram obtidos através de uma plataforma de força AMTIOR6-6-2000. Ambos os instrumentos capturaram os dados simultaneamente na frequência de 100 Hz. O tempo de duração de cada tentativa foi de 30 segundo. Na análise estatística inicial utilizou-se: Shapiro-Wilk para o teste de normalidade dos dados e as características dos indivíduos e as variáveis estudadas foram submetidas à estatística descritiva. Para a comparação das situações de olhos abertos e olhos fechados foram realizados o teste t pareado de Student e o teste de Wilcoxon. Os idosos não apresentaram diferenças em relação ao sexo,portanto as correlações entre CM e COP foram realizadas num único grupo de idosos. Para as correlações,utilizou-se o teste de correlação de Pearson. O nível de significância adotado foi de 5%. Resultados: As correlações entre as variáveis 95% da área de elipse, velocidade média de oscilação, amplitude ântero-posteriore amplitude médio-lateral do CM entre as respectivas variáveis do COP foram todas fortes e significativas(p<0,005). Conclusão: Esses achados demonstram que a observação do COP foi representativa na análise do controle postural estático para o grupo de idosos ativos avaliados...
In recent decades the elderly population is increasing rapidly. With this increase, itbecomes increasingly important to address issues related to the physical abilities of this population. An analysisof relevant variable is the postural control, which is important in carrying out daily tasks. The oscillations of thecenter of mass (CM), obtained by kinematics, and the center of pressure (COP) obtained by the force plate,provide variables that allow analysis of the behavior of postural control. Objective: To investigate thecorrelations between CM and COP in the elderly in the situation of static postural control. Materials andmethods: The study included 35 elderly active. To obtain the CM was used VICON system, of kinematics, anddata COP were obtained using a force plate AMTI OR6-6-2000. Both instruments simultaneously captured dataon the frequency of 100 Hz The duration of each trial was 30 seconds. In the initial statistical analysis was used:Shapiro-Wilk test for normality of the data and the characteristics of individuals and variables were subjected todescriptive statistics. To compare the situation with eyes open and eyes closed were performed the Student'spaired t test and Wilcoxon test. The elderly did not differ in relation to sex, so the correlations between CM andCOP were performed in a single group of elderlys. For the correlations, we used the Pearson correlation test.The level of significance was set at 5%. Results: The correlations between variables 95% of the area of theellipse, average speed of oscillation amplitude AP and ML breadth of CM between the respective variables ofCOP were all strong and significant (p <0.005). Conclusion: These findings suggest that the observation wasrepresentative of the COP in the analysis of static postural control in the elderly group assets valued...
Subject(s)
Humans , Male , Female , Aged , Aged , Postural Balance , Blood Pressure , Body Mass IndexABSTRACT
Assuming the ground reaction force of both feet to be the same in the same phase of a stride cycle, we establish the relationships between the time of initial foot contact and the ground reaction force, acceleration, velocity, displacement and average kinetic energy of center of mass. We employ the dispersion to analyze the effect of the time of the initial foot contact that imposes upon these physical quantities. We present results of an analytic and numerical calculation that studies the relationship between the time of initial foot contact and the ground reaction force of human gait and explores the dynamic principle of center of mass. Our study reveals that when the time of one foot's initial contact falls right in the middle of the other foot's stride cycle, these physical quantities reach extrema. An action function has been identified as the dispersion of the physical quantities and optimized analysis used to prove the least-action principle in gait. In addition to being very significant to the research domains such as clinical diagnosis, biped robot's gait control, the exploration of this principle can simplify our understanding of the basic properties of gait.
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The aim of the present study was to investigate whether personal hamstring muscular activation increased by landing with the trunk bent forward. First, 14 healthy female university students were instructed to perform normal drop landing from a 40 cm-high box on both legs. Second, subjects were directed to perform drop landing with the trunk bent forward. Using images obtained from a high-speed video camera, the upper center of mass was calculated in the sagittal plane for determining the differences in these landings. For 0.1 second after toe contact, the muscular activation of quadriceps femoris and hamstring muscles was analyzed using an electromyogram (EMG), and these findings were compared between the 2 types of landings. There was no significant difference in the activation of quadriceps femoris, but the activation tended to decrease during landing with the trunk bent forward. However, the activation of hamstring muscles increased significantly during landing with the trunk bent forward compared with that during normal landing. During landing with the trunk bent forward, the activation of hamstring muscles increased, and the activation of quadriceps femoris tended to decrease. Because contraction of hamstring muscles decreases tension in the anterior cruciate ligament, the findings of this study may help in the prevention of anterior cruciate ligament (ACL) injury.
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Objective To investigate any correlation between walking capacity, center of mass, and pelvic and hemiparetic lower limb motions in stroke survivors. Methods The kinematic variables studied included maximum walking speed, center of mass ( CoM ), pelvic movements and lower-limb movements on the paretic side. These were examined using a three-dimension motion analysis system as thirty-two post-stroke hemiparetic patients walked without aids. Results Average walking capacity was significantly correlated with lateral shifting of the CoM, with paretic limb hip extension, and with deficient knee flexion motions. There was a significant correlation between lateral CoM shifting and paretic limb hip extension and also deficient knee movement. Conclusions Walking capacity after stroke is associated with the lateral shifting of the CoM, paretic limb hip extension and deficient knee flexion. The lateral CoM shifting was associated with paretic limb hip extension and deficient knee movements.
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Objective: To evaluate the reliability of the digital marker tracing method combined with center-of-mass algorithm in measuring human pelvic displacement. Methods: Six cadaveric specimens of the third lumbar vertebra to the proximal 1/3 part of femur were used in present study. The specimens had no structural abnormality and all the soft tissues were dissected, reserving the hip joint capsules and the ligaments of the pelvic ring and floor. Markers with black dots against white back-ground were used to mark the key points of the pelvis. Axial loadings from the proximal lumbar (simulating the two-legged stance) were applied by MTS in the gradient of 0 N to 500 N. Images of the front and lateral views were obtained using two CCD cameras. Using Image J software, we calculated the vertical displacement of S1, (the first sacral vertebrae) in the front view and the micro-angular rotation of sacroiliac joint in the lateral view by measuring the marker's movement. Results: There was good correlation between the marked points before and after deformation of the pelvis, with the average correlation coefficient being 0. 983. Based on the 768 X 576 pixels, pixel size (mm) 0. 681 5 X 0. 681 5 image,the accuracy of the displacement was about 0. 018 pixels and the comparative error could reach 1. 11‰. The load-displacement curves obtained in this study accorded well with the clinical results. The pelvic load-displacement curve exhibited approximately a linear behavior; the sacroiliac joint load-angular rotation curve in the sagittal plane exhibited a non-linear behavior. Under a vertical load of 500 N,the average vertical displacement of S1, of the pelvis was (0. 835 6 ± 0. 283 0) mm and the average micro-angular rotation of sacroiliac joint in lateral view was (0. 584 ±0. 221). Conclusion: Digital marker tracing method combined with the center-of-mass algorithm is a simple, accurate method for measurement of pelvic displacement, which can be widely used in biomechanical research.
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El salto vertical es una habilidad relevante en el desempeño de muchos deportes de alto rendimiento, como el voleibol, básquetbol y fútbol. El gesto está basado en un conjunto de variables independientes específicas, cada una de las cuales puede afectar o favorecer en el rendimiento final. En este trabajo se realizó un análisis cinemático del salto vertical en deportistas amateurs sin antecedentes patológicos en extremidades inferiores, por medio de dos técnicas de squat jump. Para esto, se utilizó un sistema de videografía bidimensional y softwares desarrollados anteriormente en el laboratorio de biomecánica. Se evaluaron los ángulos entre segmentos, posiciones y desplazamientos de los centros de gravedad y velocidades de las articulaciones anatómicas, en cada variante del ejercicio. Los resultados obtenidos permiten caracterizar el gesto realizado y comparar las dos técnicas evaluadas. Se demostró que la técnica mejora el desempeño del salto vertical cuando se usa el balanceo de los brazos, aumentando la altura del centro de masa del cuerpo entero. El estudio demuestra ser una herramienta factible como referencias para futuros análisis del salto vertical en extremidades inferiores.
Vertical jumping is a crucial ability in the performance of several sports such as volleyball, basketball and football. The standing vertical jump is based on several specific independent variables, where each can affect or improve the final performance. The main goal of this study was to examine the kinematic vertical jump in amateurs sportsmen without pathological antecedents in lower limbs, through two types of squat jump. The movement was analyzed using two-dimensional video system and the data were processed with the use of software developed in the laboratory. The angles among segments, positions and displacements of the center of mass and anatomical joints velocities were evaluated, in each variant of the exercise. The results obtained allow the characterization of the standing vertical jump performed by the subject and allow the comparison of both techniques as well. It was demonstrated that this technique improves performance of the vertical jump while using arm swing which leads to an increase in height of the body's center of mass.
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OBJECTIVE: As the rapid progress of aged society, there must be solutions of preparation against unpredicted accidents for aged solitary people. The most important thing that we must consider is the unconstraint of daily life. So, we are to develop a system and algorithm which meet our objectives. METHODS: We have monitored the degree of activity of the aged solitary person. The CCD camera was used not to disturb the daily activity and we evaluated the degree of activity using image processing on personal computer. The activity monitoring during night was assumed by sleeping on the bed, so the major method was breath monitoring during sleeping. On the other hand, daily activity was monitored by wide viewing camera in the living room. To prevent the privacy trouble, the acquired image was converted to binary form and the degree of breath and moving factor was estimated. RESULTS: In this paper we propose a new processing algorithm to accurately measure breathing characteristics in sleep apnea sufferers. We improved the conventional center-of-mass method and further applied the projection-profile method. As a result, we have improved breath measurement accuracy. In a comparison with conventional polysomnography, our method was 92% effective in detecting apnea cases. CONCLUSION: As a result of this study, we can monitor sleep apnea more simply and with no sleep interference. In measuring the activity of daily life, these improved algorithms were applied. So, we established a monitoring method of no-constrained, quantitative measurement for the aged solitary people during the whole day.
Subject(s)
Humans , Apnea , Hand , Microcomputers , Polysomnography , Privacy , Respiration , Sleep Apnea SyndromesABSTRACT
OBJECTIVE: A sleep apnea is the most frequent symptom among sleep disorders. As the number of aged people are increasing, research activities are also increasing to monitor sleeping disorders of the elderly who lives alone. We proposed a new processing algorithm to measure the quantity of breaths accurately. METHODS: We improved the conventional center-of-mass method and further apply the projection profile method. RESULTS: In this study a system that can monitors respiration non-invasively and automatically, by identifying the movement of the chest and abdomen using image processing technique during sleep, was implemented. We can see breathing status in real time based on the acquired breathing waves. To verify the designed system, the values from the polysomnography were compared and analyzed to validate the system accuracy. As a result, the mean accuracy is 96%. CONCLUSION: We can simply monitor the sleep apnea with no sleep interferences.
Subject(s)
Aged , Humans , Abdomen , Polysomnography , Respiration , Sleep Apnea Syndromes , Sleep Wake Disorders , ThoraxABSTRACT
This study is to determine the biomechanical characteristics of Korean adults. Male 32 and female 28 were participated for the measurement which was performed by immersion method and reaction board method. Body segments were head with neck, trunk, upper arm, forearm, hand, thigh, leg and foot. Their volumes were measures by immersion method. Their weight were determined by using Dempster (1955), Drills and Contini (1969) density data. Each COM (center of mass) of body segment weight were determined by specific posture on the reaction board. The postures were asked to the subject total arm-lifted posture, forearm-lifted posture, total leg-lifted posture, leg-lifted posture. According to each posture, the COM of each segment were calculated. Also, center positions of mass according to posture change were estimated. The results were compared with cadaver data from Dempster (1955), Cluaser (1969), Matsui (1958) which are applied very often and also bio data from Lim (1994) and Jung (1993) on Korean adults.