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After a stroke, gait and balance are often affected and an orthosis is typically required to facilitate postural control. This study has been conducted to examine how the Range of Motion in an Ankle-Foot-Orthosis (AFO) impacts on stroke patients’ dynamic balance. It was hypothesized that better dynamic balance would be recorded when individuals were wearing a flexible AFO. The tests that was used in this study were the Timed Up and Go test (TUG), and the Center of Pressure (CoP)/Center of Mass (CoM) inclination angle, both in Anterior-Posterior (AP) and Medio-Lateral (ML) planes. The three patients participating in this study were all users, or had been users of AFO’s, and during the study they were asked to wear a customized AFO with the possibility to change the settings to open, flexible and rigid ankle joints. The order was randomized within each patient. No clear pattern was observed across all patients, either in the TUG test or CoP/CoM inclination angles. Further studies are required to explore the impact that AFO flexibility has on dynamic balance in individuals who have had a stroke.

Nas últimas décadas a população idosa vem aumentando rapidamente. Com o avanço da idade, os indivíduos têm diversas perdas morfológicas, funcionais e mecânicas. Assim, 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 e movimentos das articulações, obtidas por cinemática, e o centro de pressão, obtido através da plataforma de força, fornecem variáveis que permitem análise do comportamento do controle postural. O controle postural e a execução de dupla-tarefa são amplamente estudados na população idosa. No entanto, a grande maioria de estudos não utiliza ou não fornece dados referentes à validade dos testes adjacentes utilizados ao controle postural. O objetivo central do estudo foi determinar a confiabilidade teste-reteste, a reprodutibilidade intra-avaliador, a objetividade, a sensibilidade e a validade do instrumento (teste do laser) criado para ser utilizado em testes adjacentes ao controle postural (dupla-tarefa). Além disso, objetivou-se comparar o controle postural entre adultos-jovens e idosos em diferentes alturas com desafio de duplatarefa. Também foi objetivo desse estudo, verificar as correlações entre variáveis do centro de massa (COM) e do centro de pressão (COP) em idosos na situação de controle postural quase-estático. Para obtenção dos dados cinemáticos foi utilizado o sistema VICON e os dados do COP foram obtidos através de uma plataforma de força AMTI OR6-6-2000. Ambos os instrumentos capturaram os dados simultaneamente na frequência de 100 Hz. O tempo de duração de cada tentativa foi de 30 segundos. Os achados do presente estudo mostraram que o teste do laser possui confiabilidade, validade, reprodutibilidade, sensibilidade e foi válido como teste adicional para o controle postural. Os idosos têm pior controle postural que adultos-jovens, fazendo maior uso da estratégia do quadril na manutenção do equilíbrio. Em situação elevada, os valores de oscilação corporal foram maiores que em nível do solo. Os idosos apresentaram maiores deslocamentos do COP que adultos-jovens tanto elevados quanto em nível do solo. Com relação aos testes utilizados como dupla-tarefa, conclui-se que todos foram capazes de alterar os valores em comparação com tarefa simples. As correlações entre as variáveis área da elipse, velocidade média de oscilação, amplitude ântero-posterior e amplitude médio-lateral do COM e as respectivas variáveis do COP foram todas fortes e significativas. / In recent decades the elderly population is increasing rapidly. With advancing age, individuals have different morphological, functional and mechanical losses. So it is important to address issues related to physical abilities of this population. A relevant variable analysis is postural control, which is important in carrying out daily tasks. The oscillations of the center of mass and movement of the joints, obtained by kinematics, and the center of pressure, obtained by force platform, provide variables that allow analysis of postural control behavior. Postural control and dual-task execution are widely studied in the elderly. However, most studies do not use or do not provide data concerning the validity of the tests used adjacent to the postural control. The main objective of the study was to determine the test-retest reliability, intra-examiner reproducibility, objectivity, sensitivity and instrument validity (laser test) designed for use in adjacent tests to postural control (dual-task). In addition, the objective was to compare the postural control among young adults and elderly people in different heights with dual-task challenge and verify the correlations between COM and COP in the elderly in the static postural control situation. To obtain kinematic data was used VICON system and COP data were obtained through a force platform AMTI OR6-6-2000. Both instruments simultaneously captured data at a frequency of 100 Hz. The duration of each trial was 30 seconds. The finding of this study showed that the laser test has reliability, validity, reproducibility, sensitivity, and was valid as an additional test for postural control. The elderly have worse postural control than young adults, making greater use of the hip strategy in maintaining balance. In high position, the body oscillation values were higher than in the ground. The elderly had higher COP shifts than young adults so high as in the ground level. Regarding the tests used as dual-task, it is concluded that all were able to change the values compared to simple task. The correlations between variables area of the ellipse, average speed of oscillation, anteroposterior amplitude and medial-lateral extent of the COM and its COP variables were all strong and significant.

Nas últimas décadas a população idosa vem aumentando rapidamente. Com o avanço da idade, os indivíduos têm diversas perdas morfológicas, funcionais e mecânicas. Assim, 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 e movimentos das articulações, obtidas por cinemática, e o centro de pressão, obtido através da plataforma de força, fornecem variáveis que permitem análise do comportamento do controle postural. O controle postural e a execução de dupla-tarefa são amplamente estudados na população idosa. No entanto, a grande maioria de estudos não utiliza ou não fornece dados referentes à validade dos testes adjacentes utilizados ao controle postural. O objetivo central do estudo foi determinar a confiabilidade teste-reteste, a reprodutibilidade intra-avaliador, a objetividade, a sensibilidade e a validade do instrumento (teste do laser) criado para ser utilizado em testes adjacentes ao controle postural (dupla-tarefa). Além disso, objetivou-se comparar o controle postural entre adultos-jovens e idosos em diferentes alturas com desafio de duplatarefa. Também foi objetivo desse estudo, verificar as correlações entre variáveis do centro de massa (COM) e do centro de pressão (COP) em idosos na situação de controle postural quase-estático. Para obtenção dos dados cinemáticos foi utilizado o sistema VICON e os dados do COP foram obtidos através de uma plataforma de força AMTI OR6-6-2000. Ambos os instrumentos capturaram os dados simultaneamente na frequência de 100 Hz. O tempo de duração de cada tentativa foi de 30 segundos. Os achados do presente estudo mostraram que o teste do laser possui confiabilidade, validade, reprodutibilidade, sensibilidade e foi válido como teste adicional para o controle postural. Os idosos têm pior controle postural que adultos-jovens, fazendo maior uso da estratégia do quadril na manutenção do equilíbrio. Em situação elevada, os valores de oscilação corporal foram maiores que em nível do solo. Os idosos apresentaram maiores deslocamentos do COP que adultos-jovens tanto elevados quanto em nível do solo. Com relação aos testes utilizados como dupla-tarefa, conclui-se que todos foram capazes de alterar os valores em comparação com tarefa simples. As correlações entre as variáveis área da elipse, velocidade média de oscilação, amplitude ântero-posterior e amplitude médio-lateral do COM e as respectivas variáveis do COP foram todas fortes e significativas. / In recent decades the elderly population is increasing rapidly. With advancing age, individuals have different morphological, functional and mechanical losses. So it is important to address issues related to physical abilities of this population. A relevant variable analysis is postural control, which is important in carrying out daily tasks. The oscillations of the center of mass and movement of the joints, obtained by kinematics, and the center of pressure, obtained by force platform, provide variables that allow analysis of postural control behavior. Postural control and dual-task execution are widely studied in the elderly. However, most studies do not use or do not provide data concerning the validity of the tests used adjacent to the postural control. The main objective of the study was to determine the test-retest reliability, intra-examiner reproducibility, objectivity, sensitivity and instrument validity (laser test) designed for use in adjacent tests to postural control (dual-task). In addition, the objective was to compare the postural control among young adults and elderly people in different heights with dual-task challenge and verify the correlations between COM and COP in the elderly in the static postural control situation. To obtain kinematic data was used VICON system and COP data were obtained through a force platform AMTI OR6-6-2000. Both instruments simultaneously captured data at a frequency of 100 Hz. The duration of each trial was 30 seconds. The finding of this study showed that the laser test has reliability, validity, reproducibility, sensitivity, and was valid as an additional test for postural control. The elderly have worse postural control than young adults, making greater use of the hip strategy in maintaining balance. In high position, the body oscillation values were higher than in the ground. The elderly had higher COP shifts than young adults so high as in the ground level. Regarding the tests used as dual-task, it is concluded that all were able to change the values compared to simple task. The correlations between variables area of the ellipse, average speed of oscillation, anteroposterior amplitude and medial-lateral extent of the COM and its COP variables were all strong and significant.

Nas últimas décadas a população idosa vem aumentando rapidamente. Com o avanço da idade, os indivíduos têm diversas perdas morfológicas, funcionais e mecânicas. Assim, 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 e movimentos das articulações, obtidas por cinemática, e o centro de pressão, obtido através da plataforma de força, fornecem variáveis que permitem análise do comportamento do controle postural. O controle postural e a execução de dupla-tarefa são amplamente estudados na população idosa. No entanto, a grande maioria de estudos não utiliza ou não fornece dados referentes à validade dos testes adjacentes utilizados ao controle postural. O objetivo central do estudo foi determinar a confiabilidade teste-reteste, a reprodutibilidade intra-avaliador, a objetividade, a sensibilidade e a validade do instrumento (teste do laser) criado para ser utilizado em testes adjacentes ao controle postural (dupla-tarefa). Além disso, objetivou-se comparar o controle postural entre adultos-jovens e idosos em diferentes alturas com desafio de duplatarefa. Também foi objetivo desse estudo, verificar as correlações entre variáveis do centro de massa (COM) e do centro de pressão (COP) em idosos na situação de controle postural quase-estático. Para obtenção dos dados cinemáticos foi utilizado o sistema VICON e os dados do COP foram obtidos através de uma plataforma de força AMTI OR6-6-2000. Ambos os instrumentos capturaram os dados simultaneamente na frequência de 100 Hz. O tempo de duração de cada tentativa foi de 30 segundos. Os achados do presente estudo mostraram que o teste do laser possui confiabilidade, validade, reprodutibilidade, sensibilidade e foi válido como teste adicional para o controle postural. Os idosos têm pior controle postural que adultos-jovens, fazendo maior uso da estratégia do quadril na manutenção do equilíbrio. Em situação elevada, os valores de oscilação corporal foram maiores que em nível do solo. Os idosos apresentaram maiores deslocamentos do COP que adultos-jovens tanto elevados quanto em nível do solo. Com relação aos testes utilizados como dupla-tarefa, conclui-se que todos foram capazes de alterar os valores em comparação com tarefa simples. As correlações entre as variáveis área da elipse, velocidade média de oscilação, amplitude ântero-posterior e amplitude médio-lateral do COM e as respectivas variáveis do COP foram todas fortes e significativas. / In recent decades the elderly population is increasing rapidly. With advancing age, individuals have different morphological, functional and mechanical losses. So it is important to address issues related to physical abilities of this population. A relevant variable analysis is postural control, which is important in carrying out daily tasks. The oscillations of the center of mass and movement of the joints, obtained by kinematics, and the center of pressure, obtained by force platform, provide variables that allow analysis of postural control behavior. Postural control and dual-task execution are widely studied in the elderly. However, most studies do not use or do not provide data concerning the validity of the tests used adjacent to the postural control. The main objective of the study was to determine the test-retest reliability, intra-examiner reproducibility, objectivity, sensitivity and instrument validity (laser test) designed for use in adjacent tests to postural control (dual-task). In addition, the objective was to compare the postural control among young adults and elderly people in different heights with dual-task challenge and verify the correlations between COM and COP in the elderly in the static postural control situation. To obtain kinematic data was used VICON system and COP data were obtained through a force platform AMTI OR6-6-2000. Both instruments simultaneously captured data at a frequency of 100 Hz. The duration of each trial was 30 seconds. The finding of this study showed that the laser test has reliability, validity, reproducibility, sensitivity, and was valid as an additional test for postural control. The elderly have worse postural control than young adults, making greater use of the hip strategy in maintaining balance. In high position, the body oscillation values were higher than in the ground. The elderly had higher COP shifts than young adults so high as in the ground level. Regarding the tests used as dual-task, it is concluded that all were able to change the values compared to simple task. The correlations between variables area of the ellipse, average speed of oscillation, anteroposterior amplitude and medial-lateral extent of the COM and its COP variables were all strong and significant.

A escoliose idiopática do adolescente (EIA) é uma deformidade da coluna vertebral que acomete indivíduos entre 10 e 19 anos de idade, caracteriza-se por desvios das curvas nos planos frontal e sagital, e rotação intervertebral no plano axial. Devido a sua natureza tridimensional apresenta alterações biomecânicas que geram adaptações em músculos e ligamentos da coluna vertebral, alterando suas funções no controle postural. O tratamento cirúrgico visa corrigir os desvios e manter as curvas no plano sagital, através de artrodeses. Com base nesses conceitos, o objetivo do estudo foi avaliar a influência da escoliose idiopática do adolescente, e da sua correção cirúrgica, sobre o equilíbrio semi-estático. Participaram do estudo 30 adolescentes divididas em dois grupos: Grupo Controle (GC) [n=15], idade média de 15,13 ± 1,59 anos, massa corporal de 51,22 ± 2,5Kg e estatura de 159 ± 3cm, e Grupo Escoliose (GE) [n=15] com média de idade de 15 ± 1,64 anos, massa corporal de 46,1 ± 3,26Kg e estatura de 156 ± 3cm; das quais foi mesurada a oscilação do centro de pressão a partir de uma plataforma de força avaliando as variáveis: desvio ântero-posterior (DAP); desvio médio-lateral (DML); velocidade ântero-posterior (VAP); velocidade médio-lateral (VML) e área (A²). O GC realizou a avaliação do equilíbrio semi-estático em um único momento, enquanto o GE realizou a avaliação do equilíbrio semi-estático no momento pré-operatório (PRÉ) e no 7°, 30°, 60° e 90° dia de pós-operatório (PO). Foi avaliado o grau de correção da curvatura e a relação entre número de vértebras artrodesadas e a oscilação corporal. O equilíbrio semi-estático foi avaliado nas 4 posições de Romberg (P1 - pés separados, P2 - pés unidos, P3 - série parcial e P4 - série completa) nas condições olhos abertos (AO) e olhos fechado (OF). Os resultados mostram que o GE apresentou uma redução média de 49,8° para a curva torácica e 18,14° para as lombares. O número de vértebras artrodesadas foi de 11,26 ± 1,7. O GE apresentou maior oscilação que o GC, com diferença significativa nas quatro variáveis estudadas (DAP, DML, VAP, VML e A²) e em todas as posições/condições. Com base nos resultados verificou-se que o GE oscila mais que o GC tanto no pré-operatório como nos momentos pós-operatório. Na comparação entre as posições, GE oscilou mais no sentido AP em P1 e no sentido ML em P4, também obteve maior valor para a A². Para a VAP P2 foi a mais desafiadora e para VML foi P4. Os dados apontam para uma diminuição gradativa da oscilação com o passar dos dias de PO, porém no 90° dia o GE ainda apresenta valores superiores ao momento PRÉ. Portanto, os resultados mostram que a escoliose afeta o controle postural e que no 90° dia pós-cirúrgico a oscilação postural ainda se apresenta superior ao período pré-operatório, e que pode estar associado a um comprometimento sensório-motor ou a um problema de integração sensorial pré-existente, também relacionado as alterações biomecânicas decorrentes da cirurgia e seu efeito agudo. / The adolescent idiopathic scoliosis (AIS) is a spinal deformity that affects individuals between 10 and 19 years of age, characterized by deviations of the curves in the frontal and sagittal planes, and intervertebral rotation in the axial plane. Due to its three-dimensional nature presents biomechanical changes that cause changes in muscles and ligaments of the spinal column, altering their functions in postural control. Surgical treatment aims to correct the deviations and maintain the curves in the sagittal plane through arthrodesis. Based on these concepts, the study aimed to evaluate the influence of adolescent idiopathic scoliosis and its surgical correction on the semi-static balance. The study included 30 adolescents divided into two groups: control group (CG) [n = 15], mean age 15.13 ± 1.59 years, body mass 51.22 ± 2.5kg and height 159 ± 3cm, and scoliotic group (SG) [n = 15] mean age 15 ± 1.64 years, body mass index of 46.1 ± 3.26kg and height 156 ± 3cm, which was gauged from the oscillation the center of pressure from a force platform to evaluate the variables: anteroposterior deviation (APD); average-lateral devitation (MLD); anteroposterior speed (APS); average-lateral speed (MLS) and area (A²). CG carried out the assessment of the semi-static balance in a single moment, while the SG was evaluated at the preoperative period (PRE) and at the 7th, 30th, 60th and 90th days post operative (PO). We assessed the degree of curvature correction and the relationship between number of vertebrae arthrodesed and body sway. The static balance was assessed in 4 Romberg\'s positions (P1 - feet apart, P2 - feet together, P3 - partial series P4 and - full series) in eyes open conditions (EO) and eyes closed (EC). The results show that the SG had an average reduction of 49.8 degrees for the thoracic curve and 18.14 degrees for the lumbar. The number of vertebrae arthrodesed was 11.26 ± 1.7. The SG showed greater sway than the CG, with a significant difference in the four variables (APD; MLD; APS; MLS and A²) and in all positions/conditions. Based on the results it was found that the SG oscillates more than the CG (preoperatively and postoperatively). Comparing the positions of the SG volunteers ranged more towards AP in P1 and P4 in the ML direction, which also had higher values for the A². For the APS P2 was the most challenging and MLS was P4. The data indicate a gradual decrease of the oscillation over the postoperative days, but in the 90th day the GE still has higher values when the PRE. Therefore, the results show that scoliosis affects postural control and at the 90th day after the surgery the postural oscillation still superior tham postsurgery period, and maybe it can be associated with an impaired sensorimotor or a sensory integration problem pre-existing, related to the biomechanical changes followed from the surgery and its acute effect.

Notre objectif a été d'étudier l'apport d'une analyse temps-fréquence par transformée en ondelettes dans l'évaluation stabilométrique de la stabilité posturale de sujets présentant une pathologie neurologique. A partir d'un corpus de données incluant 199 patients présentant une pathologie neurologique et 41 sujets témoins, nous avons étudié la reproductibilité et la validité des paramètres stabilométriques. Nous avons déterminé les valeurs d'erreur de mesure de paramètres issus d'une analyse temps-fréquence, d'une analyse fréquentielle par méthode FFT et d'une analyse linéaire du signal, chez des patients hémiplégiques vasculaires. Pour la moyenne de 3 acquisitions de 30 secondes, nous proposons de privilégier l'utilisation de paramètres issus d'une analyse temps-fréquence qui sont les plus reproductibles. L'évaluation stabilométrique a montré un intérêt au moins équivalent aux critères cliniques dans la prédiction du risque de chute chez le patient hémiplégique vasculaire. Le modèle de prédiction reste cependant insuffisant pour être appliqué de manière isolé en pratique clinique, où une évaluation multi-modale du patient reste nécessaire. Une étude des déterminants neurologiques et biomécaniques de la distribution du contenu fréquentiel a été réalisée avec l'analyse en ondelettes. Nous avons montré qu'en l'absence de tremblement postural caractérisé, la distribution du contenu fréquentiel était essentiellement liée au degré d'instabilité posturale. Nos perspectives sont d'approfondir l'intérêt de l'analyse temps-fréquence par transformée en ondelettes, qui permet d'étudier à la fois la stabilité posturale et les mécanismes de contrôle sous-jacents. / Our objective was to study the interest of time-frequency analysis by wavelet transform in stabilometric assessment of postural sway in neurological patients. From a corpus of data including 199 patients with neurological disease and 41 control subjects, we studied the reliability and validity of stabilometric parameters. We determined the error measurement from a time-frequency analysis, a FFT analysis and a linear analysis of the stabilogram, in stroke patients. For the average of 3 acquisitions of 30 seconds, we propose to use the time-frequency parameters that are most reliable. Stabilometric assessment showed an interest at least equivalent to clinical criteria in predicting the risk of falls in the stroke patient. The prediction model remains insufficient to be applied alone in clinical practice, where a multi-modal patient assessment is still required. A study of the neurological and biomechanical determinants of the distribution of frequency content was carried out with the wavelet analysis. We have shown that in the absence of postural tremor, the distribution of frequency content was mostly related to the degree of postural instability. Our outlook is to deepen the time-frequency analysis by wavelet transform, which allows to study both postural stability and the underlying control mechanisms.

Context: Knee pain is experienced by many people. Because of this, authors have started researching the effects of pain on lower extremity mechanics and also on static and dynamic postural control. However, the effects of pain are difficult to study due to associated confounding variables. Objective: We asked: (1) Will experimentally-induced anterior knee pain alter perceived pain using the visual analogue scale? ; (2) will perceived pain affect postural control as measured by center-of-pressure during static and dynamic movement? Design: Crossover. Setting: Biomechanics laboratory. Participants: Fifteen healthy subjects. Intervention: Each subject participated in single leg quiet stance, landing, and walking trials under three conditions (pain, sham, control), at three different times for each condition (pre-injection, injection, and post-injection). Main Outcome Measures: The dependent variables were measured at pre-injection, injection, and post-injection. Pain was measured using the visual analogue scale across all three times during each condition. Center-of-pressure sway was measured during single leg quiet stance to calculate the average center-of-pressure velocity in the anterior-posterior and medial-lateral directions. The center-of-pressure time to stabilization was measured in anterior-posterior, medial-lateral, and vertical directions, and center-of-pressure trajectory excursion was measured in the medial-lateral direction during walking. Results: Perceived pain was significant (P < 0.05) but did not affect postural control as measured by center-of-pressure medial-lateral and anterior-posterior sway during single leg quiet stance, in time to stabilization during landing, and in medial-lateral excursion during walking. Conclusions: Injection of hypertonic saline resulted in statistically significant perceived pain but did not affect postural control as measured by center-of-pressure medial-lateral and anterior-posterior sway during single leg quiet stance, in time to stabilization during landing, and medial-lateral excursion during walking.

The most common way to measure postural stability is to examine the displacement of the center of pressure (CoP). But some scientists claim that the center of mass (CoM) is what really indicates the sway of the whole body, since the body is a multi-joint system. Many previous studies of human balance have targeted groups with diffrent kinds of balance impairments. In a recent study C. Lidbeck investigated factors influencing standing in children with bilateral spastic cerebral palsy (BSCP). The conclusion of that study was that the crouched position, that is common with this kind of disability, was not found to be related to strength and not entirely related to the degree of their motor disorders. In this thesis a number methods were chosen to assess the postural stability of children with BSCP, using both the CoP and the CoM. The hypothesis was that the different methods would show different aspects of the children's balance impairment. Also, the influence of visual stimuli on the crouching position was examined. The long term aim is that the results may contribute to a deeper understanding of the balance disturbances that often accompany this group of children. 16 children with BSCP (GMFCS level I-III) and 20 typically developing (TD) children were included in the study. Data was collected, before the start of this project, using two force plates and an eight-camera 3D motion analysis system with passive markers. The children performed three different standing tasks during 30 seconds each; quiet standing, blindfolded and an attention-task. Five methods were chosen (based on previous literature) and implemented in Matlab to examine the postural stability of the two groups during the three tasks. Result shows that all methods used can clearly distinguish between the balance in the BSCP group and the TD group. When comparing the quiet standing task with the blindfolded task in the BSCP group, there were some significant results from the statistical evaluation (P$&lt;$0.05). The result from several of the methods indicated that the children of this group have better postural stability when blindfolded, which is not in agreement with previous literature. In contrast, one method using the total mean velocity indicated that the postural stability decreased. During the attention-task, the methods disagreed with each other, implying a change in balance strategy in the BSCP group that was different from the TD group. Four methods are suggested for future studies, two using the CoP and two using the CoM. These four methods highlighted different aspects of the data and in combination they may provide a bigger picture of the postural stability of children with BSCP. Even though there were no significant difference in the vertical displacement of the CoM between the BSCP and the TD group, the CoM was slightly elevated during the attention-task in the BSCP group. In the TD group the CoM was lowered during the same task. This indicates that the children with BSCP in this study straighten up a bit when they can focus on something outside of their own body.

The objectives of this study were to implement force sensors on the feet of a bipedal robot and analyze their response at different conditions. The data will be used to design a control strategy for the robot. The powered joints of the robot are driven by linear motors. A force sensor circuit was made and calibrated with different kinds of weight. A trajectory generator and inverse kinematics calculator for the robot were made to control the robot walking movement in an open-loop manner. The force data were taken at a certain period of time when the robot was in a standing position. Experiments with external disturbances were also performed on the robot. The ZMP position and mass of the robot were calculated by using the data of force sensors. The force sensor circuit was reliable in taking and handling the data from the sensor although the noise from the motors of the robot was present. / <p>Validerat; 20111115 (anonymous)</p>