This thesis examined Autonomic Nervous System activity evoked by postural instability. Autonomic reactions were assessed using measures of electrodermal activity at the surface of the skin. Perturbation-evoked electrodermal responses (EDRs) were consistently observed in conjunction with both upper and lower limb postural reactions. These autonomic responses were sensitive to perturbation amplitude, as well as experimental manipulations which did not influence the perturbation itself but which affected response execution. In particular, stimulus predictability and movement challenge modulated EDRs, although purely cognitive manipulations did not significantly affect autonomic responses. Probes examining the potential role of such autonomic potentials in compensatory balance control revealed that EDRs evoked during compensatory postural reactions were larger and more consistent than potentials evoked by purely motor or sensory stimuli, suggesting that evoked autonomic activity plays a role in compensatory behavior. While the specific role of autonomic contributions in compensatory balance control require further study, speculative models for autonomic contributions propose either feedback-based pathways for detection of instability to initiate the postural reaction, and/ or an adaptive role to higher centers important for establishing sensorimotor gain in future conditions. This thesis presents new evidence regarding basic neural mechanisms engaged in the recognition and response to postural instability, and future work may extend these findings in clinical populations with high fall incidence and offer clues as to alternative causes for falls and fall prevention.

This thesis examined Autonomic Nervous System activity evoked by postural instability. Autonomic reactions were assessed using measures of electrodermal activity at the surface of the skin. Perturbation-evoked electrodermal responses (EDRs) were consistently observed in conjunction with both upper and lower limb postural reactions. These autonomic responses were sensitive to perturbation amplitude, as well as experimental manipulations which did not influence the perturbation itself but which affected response execution. In particular, stimulus predictability and movement challenge modulated EDRs, although purely cognitive manipulations did not significantly affect autonomic responses. Probes examining the potential role of such autonomic potentials in compensatory balance control revealed that EDRs evoked during compensatory postural reactions were larger and more consistent than potentials evoked by purely motor or sensory stimuli, suggesting that evoked autonomic activity plays a role in compensatory behavior. While the specific role of autonomic contributions in compensatory balance control require further study, speculative models for autonomic contributions propose either feedback-based pathways for detection of instability to initiate the postural reaction, and/ or an adaptive role to higher centers important for establishing sensorimotor gain in future conditions. This thesis presents new evidence regarding basic neural mechanisms engaged in the recognition and response to postural instability, and future work may extend these findings in clinical populations with high fall incidence and offer clues as to alternative causes for falls and fall prevention.

名古屋大学博士学位論文 学位の種類 : 博士(医学)(論文) 学位授与年月日:平成4年12月22日 市川真澄氏の博士論文として提出された

Travel time has generally been regarded as an unproductive period, representing a means-to-an-end in order to engage in activities at specific destinations. Rapid developments in mobile technology have provided people with innovative ways to multi-task and engage in meaningful activities while travelling. Rail transportation specifically, offers passengers advantages over other means of transportation as there is no need to focus on driving tasks. Due to the increase in passenger numbers and limited seating availability in train carriages, over one third of rail passengers are required to stand while travelling (DfT, 2013). The vibration to which rail passengers are exposed has been shown to interfere with the performance of activities and for standing passengers, it is often necessary to use postural supports such as holding on to grab rails or leaning on walls in order to maintain stability. The overall aim of the research is to evaluate the influence of whole-body vibration (WBV) exposure and standing posture on the performance of manual control tasks and the associated subjective workloads experienced by rail passengers. The use of supports, such as a backrest in seated postures, has been found to influence the response of the human body to WBV exposure, yet no reported studies have investigated the effects of postural supports on the response of the body in standing postures. Understanding how the body is affected in these conditions would increase the current state of knowledge on the biomechanical responses of the human body to vibration exposure and provide improved representation of standing postures within vibration standards (for example, ISO2631-4 (2001)) and guidelines for device interface design. A field study, using direct observation, was conducted to assess the behaviour of standing rail passengers and determine the characteristics of typical vibration exposures. This information provided the basis for the design of four subsequent laboratory studies. The main investigations of the laboratory studies were the influence of WBV exposure on objective performance measures, such as task completion time and error rate, and subjective workloads (for example, NASA TLX) for a range of manual control tasks. One of these laboratory studies evaluated the influence of various postural supports (for example, backrests) on the biomechanical responses of standing individuals. Measurements obtained during the field investigation indicated that the vibration exposures did not exceed the EU Physical Agents Exposure Action Value (EAV) and therefore posed little risk of injury. Vibration magnitudes in the horizontal directions (x- and y-axes) were higher than in the vertical direction (z-axis) and it was necessary for standing passengers to alter behaviours and use supports in order to maintain stability while travelling. The results of the laboratory studies indicated that in conditions where decrements in task performance occurred, the extent to which performance was degraded increased progressively with increases in vibration magnitude. There were conditions (for example, in the continuous control task and the Overhead Handle supported posture in the serial control task) where vibration exposure showed no significant influence on performance measures. This suggested that individuals were able to adapt and compensate for the added stress of vibration exposure in order to maintain performance levels however, this occurred at the expense of mental workload. The workload experienced by the participants increased with corresponding increases in magnitude. Vibration frequency-dependent effects in performance and workload were found to match the biomechanical responses (apparent mass and transmissibility) of the human body and resemble the frequency weightings described in the standards (ISO2631-1 (1997)). During the serial control task, the postures which demonstrated the greatest decrements to performance (for example, Lean Shoulder and Lean Back ) corresponded to the same postures that showed the greatest influence on the biomechanical responses of the body. It was concluded therefore, that measurements of the biomechanical responses to WBV could be used to offer predictions for the likelihood of activity interference. Consideration should however, be given to the applicability of this research before these results can be generalised to wider contexts. Further validation is recommended for future work to include different conditions in order to substantiate the findings of this research.

Background: PostureScreen Mobile® is an app created to quickly screen posture using front and side-view photographs. There is currently a lack of evidence that establishes PostureScreen Mobile® (PSM) as a valid measure of posture. Therefore, the purpose of this preliminary study was to document the validity and reliability of PostureScreen Mobile® in assessing static standing posture. Methods: This study was an experimental trial in which the posture of 50 male participants was assessed a total of six times using two different methods: PostureScreen Mobile® and Vicon 3D motion analysis system (VIC). Postural deviations, as measured during six trials of PSM assessments (3 trials with and 3 trials without anatomical markers), were compared to the postural deviations as measured using the VIC as the criterion measure. Measurement of lateral displacement on the x-axis (shift) and rotation on the y-axis (tilt) were made of the head, shoulders, and hips in the frontal plane. Measurement of forward/rearward displacement on the Z-axis (shift) of the head, shoulders, hips, and knees were made in the sagittal plane. Validity was evaluated by comparing the PSM measurements of shift and tilt of each body part to that of the VIC. Reliability was evaluated by comparing the variance of PSM measurements to the variance of VIC measurements. The statistical model employed the Bayesian framework and consisted of the scaled product of the likelihood of the data given the parameters and prior probability densities for each of the parameters. Results: PSM tended to overestimate VIC postural tilt and shift measurements in the frontal plane and underestimate VIC postural shift measurements in the sagittal plane. Use of anatomical markers did not universally improve postural measurements with PSM, and in most cases, the variance of postural measurements using PSM exceeded that of VIC. The patterns in the intraclass correlation coefficients (ICC) suggest high trial-to-trial variation in posture. Conclusions: We conclude that until research further establishes the validity and reliability of the PSM app, it should not be used in research or clinical applications when accurate postural assessments are necessary or when serial measurements of posture will be performed. We suggest that the PSM be used by health and fitness professionals as a screening tool, as described by the manufacturer. Due to the suspected trial-to-trial variation in posture, we question the usefulness of a single postural assessment.

Made available in DSpace on 2014-06-11T19:30:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-21Bitstream added on 2014-06-13T20:40:47Z : No. of bitstreams: 1 ferreira_dma_dr_rcla.pdf: 659123 bytes, checksum: baf4d8518bae6e1d0b27e68eae1725f9 (MD5) / O objetivo deste estudo foi avaliar as alterações estáticas e dinâmicas em pacientes com escoliose idiopática na posição ortostática, sem e com inclinação lateral com restrição associadas ou não as mudanças unilaterais de calços. O grupo experimental foi constituído por pacientes com escoliose idiopática com curva dupla (³ 10°) e o grupo controle por participantes sem escoliose na mesma faixa etária (13-24 anos). Foram utilizadas três câmeras de vídeo, 18 marcadores fixados em referências anatômicas dos participantes, dois calços, de 1 e de 3 cm de altura e uma escala para restrição e padronização da inclinação lateral. As tentativas foram realizadas aleatoriamente, nas condições sem calço ou com calço baixo ou alto sob o pé direito e esquerdo e nas tarefas, estática (15 segundos) ou dinâmica (5 movimentos de inclinação lateral para direita ou esquerda). Foram calculados os ângulos posturais: alfa 1 (torácico alto), alfa 2 (torácico médio), alfa 3 (tóraco-lombar) e alfa 4 (lombar) e os ângulos segmentares: beta 1 (ombros), beta 2 (escápulas), beta 3 (pelves) e beta 4 (joelhos). Na situação estática, os grupos e os calços tiveram uma maior influência nos ângulos posturais tóracolombar e lombar e nos ângulos segmentares da pelve e do joelho. Na situação dinâmica sem calço, nenhuma diferença foi observada entre grupos, porém o calço associado aos movimentos de inclinação lateral provocou ajustes posturais compensatórios nos ângulos posturais alfas e segmentares betas, sendo que as diferenças foram maiores com o calço alto nos pacientes com escoliose, indicando um possível mecanismo corretivo. Estas alterações posturais tanto estáticas como dinâmicas, indicam a busca de uma nova organização estrutural e equilíbrio do tronco, sendo que os segmentos superiores foram mais influenciados na condição dinâmica... / The purpose of this study was to evaluate static and dynamic changes in patients with idiopathic scoliosis in the orthostatic position, with and without restricted lateral inclination associated with or not unilateral changes of shoe lifting. The experimental group was constituted by patients with idiopathic scoliosis with double curve (³ 10°) and the control group by participants without scoliosis with the same age (13-24 years). Three video cameras were used, with 18 markers fixed on the participants' anatomical references, along with two shoe lifts, 1 and 3 cm of height, and a scale for restriction and standardization of the lateral inclination. The trails were accomplished randomly, in the conditions without or with shoe lift (low or high) under the right and left foot and in the tasks, static (15 seconds) or dynamic (5 movements of lateral inclination for right or left). Postural angles: alpha 1 (thoracic high), alpha 2 (thoracic medium), alpha 3 (thoracolumbar) and alpha 4 (lumbar); and segmental angles: beta 1 (shoulders), beta 2 (scapulas), beta 3 (pelvis) and beta 4 (knees) were calculated. In the static condition, group and shoe lift mostly influenced the postural angles, thoracic-lumbar and lumbar, and the segmental angles of the pelvis and knee. In the dynamic condition without shoe lift, no difference was observed between groups, however, with shoe lift.and lateral inclination compensatory postural adjustments were observed in the postural alpha angles and segmental beta angles, with the largest differences observed in the condition with the high shoe lifting in the patients with scoliosis, indicating a possible corrective mechanism. These, static and dynamics, postural changes suggest a new structural organization and equilibrium of the trunk, with the trunk upper segments being the ones more influenced by the dynamic condition with low and high shoe lifting whereas... (Complete abstract click electronic access below)

Orientador: José angelo Barela / Banca: Ana Maria Pellegrini / Banca: Cláudia Regina Sgobbi de Faria / Banca: Paula Hentschel Lobo da Costa / Banca: Rúben de Faria Negrão Filho / Resumo: O objetivo deste estudo foi avaliar as alterações estáticas e dinâmicas em pacientes com escoliose idiopática na posição ortostática, sem e com inclinação lateral com restrição associadas ou não as mudanças unilaterais de calços. O grupo experimental foi constituído por pacientes com escoliose idiopática com curva dupla (³ 10°) e o grupo controle por participantes sem escoliose na mesma faixa etária (13-24 anos). Foram utilizadas três câmeras de vídeo, 18 marcadores fixados em referências anatômicas dos participantes, dois calços, de 1 e de 3 cm de altura e uma escala para restrição e padronização da inclinação lateral. As tentativas foram realizadas aleatoriamente, nas condições sem calço ou com calço baixo ou alto sob o pé direito e esquerdo e nas tarefas, estática (15 segundos) ou dinâmica (5 movimentos de inclinação lateral para direita ou esquerda). Foram calculados os ângulos posturais: alfa 1 (torácico alto), alfa 2 (torácico médio), alfa 3 (tóraco-lombar) e alfa 4 (lombar) e os ângulos segmentares: beta 1 (ombros), beta 2 (escápulas), beta 3 (pelves) e beta 4 (joelhos). Na situação estática, os grupos e os calços tiveram uma maior influência nos ângulos posturais tóracolombar e lombar e nos ângulos segmentares da pelve e do joelho. Na situação dinâmica sem calço, nenhuma diferença foi observada entre grupos, porém o calço associado aos movimentos de inclinação lateral provocou ajustes posturais compensatórios nos ângulos posturais alfas e segmentares betas, sendo que as diferenças foram maiores com o calço alto nos pacientes com escoliose, indicando um possível mecanismo corretivo. Estas alterações posturais tanto estáticas como dinâmicas, indicam a busca de uma nova organização estrutural e equilíbrio do tronco, sendo que os segmentos superiores foram mais influenciados na condição dinâmica... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this study was to evaluate static and dynamic changes in patients with idiopathic scoliosis in the orthostatic position, with and without restricted lateral inclination associated with or not unilateral changes of shoe lifting. The experimental group was constituted by patients with idiopathic scoliosis with double curve (³ 10°) and the control group by participants without scoliosis with the same age (13-24 years). Three video cameras were used, with 18 markers fixed on the participants' anatomical references, along with two shoe lifts, 1 and 3 cm of height, and a scale for restriction and standardization of the lateral inclination. The trails were accomplished randomly, in the conditions without or with shoe lift (low or high) under the right and left foot and in the tasks, static (15 seconds) or dynamic (5 movements of lateral inclination for right or left). Postural angles: alpha 1 (thoracic high), alpha 2 (thoracic medium), alpha 3 (thoracolumbar) and alpha 4 (lumbar); and segmental angles: beta 1 (shoulders), beta 2 (scapulas), beta 3 (pelvis) and beta 4 (knees) were calculated. In the static condition, group and shoe lift mostly influenced the postural angles, thoracic-lumbar and lumbar, and the segmental angles of the pelvis and knee. In the dynamic condition without shoe lift, no difference was observed between groups, however, with shoe lift.and lateral inclination compensatory postural adjustments were observed in the postural alpha angles and segmental beta angles, with the largest differences observed in the condition with the high shoe lifting in the patients with scoliosis, indicating a possible corrective mechanism. These, static and dynamics, postural changes suggest a new structural organization and equilibrium of the trunk, with the trunk upper segments being the ones more influenced by the dynamic condition with low and high shoe lifting whereas... (Complete abstract click electronic access below) / Doutor

Title: Differences in postural activity during quiet standing when breathing abdominally. Aim and purpose: Aim of this study was to examine the effects of abdominal breathing on selected muscles and stability during quiet standing to find empirical evidence if it can reduce the strain and change the activity pattern, which erect standing demands from the muscles. Methods and materials: This thesis begins with an introduction to theoretical part in which we gathered all the already existing and written information needed to form the knowledge base for our experiment. Continuing in 9th chapter, methodology and experiment procedure are described where we measured muscle activity using surface EMG and to monitor changes in stability we used force- plate for posturography where only linear parameters were acquired. Both devices were used simultaneously while the subject was in quiet stance for a period of 90 seconds. Results: Results shown decrease in most of the muscles, with a higher increase in body sway in medio- lateral than in antero-posterior direction. Signal didn't change to a more distinct wave-like pattern of rhythmic oscillations, as we had thought it would. Keywords: Posture, quiet standing, abdominal breathing, diaphragm, system interrelation, EMG, posturography

Les adolescents-hockeyeurs peuvent être affligés de troubles musculosquelettiques (TMS) résultant d’un excès de tension musculaire lequel peut mener à des déformations ou déséquilibres musculaires ainsi qu’à une attitude posturale inadéquate. Les conséquences de ces changements mènent souvent à une surcharge inutile du système musculosquelettique (SMS), à la perturbation des mécanismes du contrôle postural et éventuellement à l’apparition de douleurs musculaires et articulaires. Les interventions qui s’attaquent aux TMS par une rééquilibration de la tension musculaire sont peu nombreuses. Les interventions qui s’attaquent aux TMS par une normalisation de la tension musculaire sont peu nombreuses. La Reconstruction Posturale® (RP), testée cliniquement, est l’une d’entre elles. Dans un premier temps, cette thèse visait à identifier les caractéristiques du contrôle postural chez les adolescents-hockeyeurs de niveau élite lorsque le système somatosensoriel est mis à l’épreuve en position debout quasi statique pieds nus et en patins. Dans un deuxième temps, nous avons évalué l’impact d’une intervention en RP sur des variables cliniques et biomécaniques, chez ces athlètes qui souffrent de TMS. Soixante-sept adolescents-hockeyeurs de niveau élite âgés de 15 à 18 ans ont participé à l’étude. Le contrôle postural de cinquante-sept joueurs a été évalué en position debout sur deux plateformes de force les yeux ouverts et les yeux fermés, pieds nus sur une surface dure et sur une mousse. De ce groupe, trente-cinq sujets ont également été évalués en patins, les yeux ouverts et les yeux fermés. Par la suite, neuf adolescents-hockeyeurs souffrant de TMS, ont été sélectionnés pour participer au protocole d’intervention thérapeutique en RP qui consistait en l’application de six séances de thérapie prodiguées sur une période de six semaines. Le déplacement du centre de pression (CP) sous les pieds a été calculé dans les directions antéro-postérieure (AP) et médio-latérale (ML). La vélocité moyenne du CP, le déplacement moyen du CP et l’étendue du CP ont été retenus pour rendre compte de la performance du contrôle posturale. D’autre part, l’asymétrie de mise en charge, la trajectoire du CP sous les pieds gauche et droit, le CPc pour rendre compte de la stratégie de chevilles et le CPv pour rendre compte de la stratégie de hanches ont été retenues pour identifier les stratégies utilisées pour maintenir l’équilibre. L’impact de l’intervention en RP a été évalué à l’aide de trois variables cliniques soit la douleur à l’aide de l’échelle visuelle analogue (ÉVA), la capacité fonctionnelle à l’aide d’un un questionnaire autoadministré et des photographies de la posture debout pour rendre compte des variables posturales biomécaniques. Nos résultats montrent que chez les adolescents-hockeyeurs la performance du contrôle postural en position debout statique est davantage perturbée par les changements somatosensoriels en direction ML alors qu’en AP, la perte d’informations visuelles ainsi que des changements somatosensoriels affectent la performance. Dans toutes les conditions expérimentales et dans les deux directions, nous avons observé une vélocité du CP remarquablement élevée, variant entre 18 et 22 mm/s. Au niveau des stratégies et indépendamment de la condition expérimentale, nous avons observé une dominance presque complète de la stratégie de cheville en AP alors qu’en ML, la stratégie de hanche dominait avec une contribution de la stratégie de cheville de plus de 20 %. En patins, en direction ML, aucun changement significatif de la performance n’a été observé. Toutefois en AP, nous avons observé une augmentation significative de la vélocité du CP, yeux ouverts et yeux fermés ainsi qu’une augmentation significative de l’étendue, yeux ouverts seulement. Au niveau des stratégies, la stratégie de cheville domine en AP et la stratégie de hanche domine en ML avec une contribution plus modeste de la stratégie de cheville qui était inférieure à 12 %. Chez les adolescents-hockeyeurs souffrant de TMS, post-intervention, nos résultats indiquent une diminution significative de la douleur et une amélioration des capacités fonctionnelles ainsi que de l’attitude posturale. Pré intervention en direction ML, nous avons observé une contribution significativement plus élevée de la stratégie de cheville au contrôle du CPnet et un retour vers des valeurs normales post-intervention. L’impact de l’intervention thérapeutique sur la performance du contrôle postural s’est avéré non significatif en ML et en AP. / Adolescent hockey players can suffer from musculoskeletal disorders (MSD) resulting from excess muscle tension that can lead to dysmorphisms, muscle imbalances as well as inadequate standing posture. The consequences of these changes often lead to unnecessary overload of the musculoskeletal system (MSS), disturbances in postural control mechanisms and eventually the development of muscular and joint pain. Very few interventions are design to address MSD by rebalancing muscle tension. One of the clinically tested interventions is Postural Reconstruction® (PR). Our first objective was to identify the characteristics of postural control among a population of elite adolescent-hockey players when the somatosensory system is disturbed while standing in a quasi static position barefoot and on skates. Secondly, we assessed the impact of an intervention in PR on various clinical and biomechanical variables among a population of elite adolescent hockey players suffering from MSD. Sixty seven elite adolescent hockey players, 15 to 18 years of age participated in the study. The postural control of fifty seven players was assessed in standing using two force platforms, in eyes open (EO) and eyes closed (EC) conditions barefoot on hard surface and on foam. From that group, thirty five players were also assessed on skates, EO and EC. Then, nine players suffering from MSD were selected to participate in the intervention protocol in RP consisting in the application of six therapeutic sessions held once a week for six consecutive weeks. Center of pressure (COP) movements under the feet was calculated in the antero-posterior (AP) and medio-lateral (ML) directions. To account for the performance of the postural control system, mean COP velocity and displacements as well COP range were used. The variables retained to account for the strategies used to maintain balance in the upright position were weight baring asymmetry, concordance of the COP trajectory as well as COPc for the contribution of the ankle strategy and COPv for the contribution of the hip strategy. Finally, the impact of PR intervention was assessed on pain level, functional capacity and postural biomechanical variables. Our results show that among elite adolescent hockey players, the performance of the postural control in standing in a quasi static position is more disturbed by changes somatosensory information in ML direction while in AP, the absence of visual information as well as changes in somatosensory information significantly affect the performance. In all experimental conditions, and in both directions, we observed a remarkably high mean velocity, ranging between 18 to 22 mm/sec. As for the strategies, independent of the experimental condition, we observed total dominance of the ankle strategy in AP while in ML, the hip strategy dominated with a 25 % contribution for the ankle strategy. On skates, in ML direction, no significant changes were observed in the performance. However, in AP, we observed a significant increase in the mean COP velocity, EO and EC, and significant increase in COP range, EO only. As for the strategies, we observed the same dominance but the contribution on the ankle strategy in ML was more modest, that is less than 12 %. For players suffering from MSD, our results show that six sessions of PR significantly improved the level of pain, functional capacity and body alignment in standing. Pre intervention in ML, we observed a significantly higher contribution of the ankle strategy to the control of the COPnet and post-intervention, a return to normal values. The impact of the PR intervention on postural control performance was not significant in ML and AP. In conclusion, our results show that in the early stage, a PR intervention has a greater impact on postural control stratégies rather than performance.