This study investigated a series of independent unassisted and device-assisted transfers from a wheelchair to vehicle mock-up and vice versa while simultaneously capturing kinematic, kinetic and electromyographic (EMG) data of impaired volunteers. The study provides a venue for observation and evaluation of upper extremity (UE) joint stresses, muscular force and functional demands associated with transfers in persons with spinal cord injury (SCI) to ultimately prevent UE injury, minimize excessive stress, preserve functionality and limit pain. If people with SCI lose function of their UEs, due to pain and/or degeneration, they must then rely on others for everyday tasks. Five paraplegic males from the Tampa Bay area were recruited to take part in the study. Participants were asked to perform a series of transfers using 4 commercially available devices or mock-ups of that device as well as an unassisted transfer, which permitted the use of no assistive device. Three data types were captured: kinematic data using motion capture, kinetic data using force transducers which were integrated into the vehicle mock-up and EMG of 5 bilateral muscle groups. Data collection took approximately 4 hours per subject. Forces occurring during the unassisted transfers were found to be the highest. This is also supported by the EMG data. Performing level transfers lessened stresses at the UE versus non-level transfers. The highest moments of the UEs were found at the shoulders with high variability between subjects. It was also found that body mass index (BMI) had an affect on a subjects ability to perform transfers. Ultimately this study found that using an assistive device is better than not using an assistive device. This is proven by EMG and force data, which were both found to be less with the use of an assistive device as opposed to transferring independently with no assistance. Performing level transfers, maintaining ones body mass and staying active are all factors that will limit stresses at the UEs during wheelchair transfers to and from a vehicle.

Correct muscular activation of the body segments during an overhand throw is achieved when movement originates in the larger and more proximal legs and trunk and moves sequentially to the smaller, distal segments of the shoulder and arm. This sequence permits angular velocity to transfer progressively through the throw as part of an open kinetic chain. The athlete can summate angular velocity and segmental forces only if he is able to create a separation between the body segments during the movement pattern, and this separation is thus essential to effective segmental sequencing for activation of the trunk muscles to occur separately from distal segment motion. Limited mobility of the shoulder and scapula during the kinematic sequence will limit the ability of that segment to receive and contribute to the angular velocity of its proximal neighbors and to apply its own muscle torque to the throwing implement. This may result in compensatory motion of the proximal muscle groups to meet the demands placed on the body. To establish a link between compensatory activation of the trunk muscles and mobility in the rotator cuff and to apply this relationship to the pattern of the overhand throw, activity in the latissimus dorsi and external oblique/quadratus lumborum muscles was measured using surface electromyography in 40 college-age participants during arm flexion and lateral shoulder rotation. Muscle activation was recorded both before and after mobilization of relevant throwing muscles through targeted functional exercise. Results showed no significant change but suggested a general decrease in the level of peak muscle activation after participants engaged shoulder exercises. This is indicative of a downward trend in compensatory trunk activation during the initiation of shoulder motion. An increase in overall trunk muscle activity was also observed after exercise, which may imply a simultaneous engagement of the proximal throwing muscles in response to shoulder motion.

Author: Bc. Veronika Szabóová Title: Comparative analysis of selected muscles activity during ropeclimbing, pull-up and its modifications. Objectives: The aim of the theoretical part of this thesis is to make a search of the available studies in the field of ropeclimbing and its training methods. The aim of this study is to evaluate the coordination of the selected muscles in terms of its timing during three specific training exercises compared to legless ropeclimbing. Methods: The theoretical part of the thesis was elaborated on the basis of information from printed and electronic sources in the Czech and English language in the form of a research. In the practical part of the thesis the activity of ten selected muscles during ropeclimbing, pull-up and its modifications was monitored. The main research method was the surface electromyography. The representative sample of 11 participants examined in the study was properly chosen from active competitors in ropeclimbing. The study evaluates the order of muscle activation compared to the legless ropeclimbing as the reference movement. The treshold method was used for detection of the muscle activity. The Spearman correlation coefficient was used to evaluate the relationship between the variables and for statistical testing. Results: In terms of timing...

Work-related musculoskeletal disorders (WMSDs) due to overexertion and consequently the low back pain (LBP) are one of the most prevalent sources of nonfatal occupational injuries and illnesses in all over the world. In the past several years, the industrial exoskeletons especially the passive ones have been proposed as alternative intervention and assistive devices, which are capable of reducing the risk of WMSDs and LBP. However, more research is warranted to validate the applicability of these exoskeletons. In addition, because the majority of previous studies have been limited to specific lifting tasks using only one type of lift assistive exoskeleton, more research is needed to examine the effect of alteration of different lift-assistive exoskeletons on reducing the activity of back muscles and metabolic reduction. The main objective of this dissertation is to render an overview of three studies that attempt to improve the literature by providing comprehensive biomechanical evaluations and metabolic assessments of three passive lift-assistive exoskeletons (VT-Lowe's Exoskeleton (developed in ARLab at VT), Laevo and SuitX). This dissertation has been composed of three related studies. The first study aimed to investigate and examine the capability of a novel lift assistive exoskeleton, VT-Lowe's exoskeleton, in reducing the peak and mean activity of back and leg muscles. Findings revealed that the exoskeleton significantly decreased the peak and mean activity of back muscles (IL(iliocostalis lumborum) and LT(longissimus thoracis)) by 31.5% and 29.3% respectively for symmetric lifts, and by 28.2% and 29.5% respectively for asymmetric lifts. Furthermore, the peak and mean EMG of leg muscles were significantly reduced by 19.1% and 14.1% during symmetric lifts, and 17.4% and 14.6% during asymmetric lifts. Interestingly, the VT-Lowe's exoskeleton showed higher reduction in activity of back and leg muscles compared to other passive lift-assistive exoskeletons available in the literatures. In the second study, the metabolic cost reduction associated with the use of VT-Lowe's exoskeleton during freestyle lifting was theoretically modelled, validated and corresponding metabolic savings were reported. The metabolic cost and the oxygen consumption results supported the hypothesis that the VT-Lowe's exoskeleton could significantly reduce the metabolic demands (~7.9% on average) and oxygen uptake (~8.7% on average) during freestyle lifting. Additionally, we presented a prediction model for the metabolic cost of exoskeleton during repetitive freestyle lifting tasks. The prediction models were very accurate as the absolute prediction errors were small for both 0% (< 1.4%) and 20% (< 0.7%) of body weight. In the third study, the biomechanical evaluation, energy expenditure and subjective assessments of two passive back-support exoskeletons (Laevo and SuitX) were examined in the context of repetitive lifting tasks. The experimental lifting tasks in this study were simulated in a laboratory environment for two different levels of lifting symmetry (symmetric vs. asymmetric) and lifting posture (standing vs. kneeling). Results of this study demonstrated that using both exoskeletons during dynamic lifting tasks could significantly lower the peak activity of trunk extensor muscles by ~10-28%. In addition, using both exoskeletons could save the energy expenditure by ~4-13% in all conditions tested by partially offsetting the weight of the torso. Such reductions were, though, task-dependent and differed between the two tested exoskeletons. Overall, the results of all three studies in this dissertation showed the capability of passive lift-assistive exoskeletons in reducing the activity of back and leg muscles and providing metabolic savings during repetitive lifting tasks. / Doctor of Philosophy / Low back pain (LBP) due to overexertion is known as one of the most important sources of nonfatal occupational injuries especially for the workers or manual material handlers who are involved in frequent or repetitive lifting tasks. Every year, many workers are temporarily or permanently disabled due to overuse injuries at workplace. In the past several years, industrial exoskeletons have gained growing interest among biomechanist, roboticist, and other human factor researchers as potential assistive devices to reduce the risk of LBP. In general, the industrial exoskeletons are either “passive or “active”; Active exoskeletons are powered by mechanical/electrical motors and actuators, however, the passive exoskeletons often work using cheaper devices such as gas or metal springs, elastic elements, etc. The exoskeletons discussed in this dissertation are categorized as passive rigid lower-back exoskeletons and they function by storing energy in a spring when the wearer bends and returning the stored energy when the wearer lifts. This dissertation consists of three studies that attempt to provide comprehensive biomechanical evaluations and metabolic assessments of three passive lift-assistive exoskeletons (i.e., VT-Lowe’s Exoskeleton, Laevo and SuitX). The first study examined the efficacy of a novel lift-assistive exoskeleton, VT-Lowe’s exoskeleton, in reducing the peak and mean activity of back and leg muscles. The results of this study demonstrated that the exoskeleton reduced the peak and mean activity of back and leg muscles for symmetric and asymmetric lifting tasks. VT-Lowe’s exoskeleton also showed higher reduction in activity of back muscles compared to other passive lift-assistive exoskeletons available in the literature. In the second study, the metabolic cost reduction with VT-Lowe’s exoskeleton was theoretically modeled and the modeling outcomes were compared to metabolic costs measurements when the exoskeleton was worn. The experimental findings of this study supported the applicability of the exoskeleton by significantly reducing the metabolic cost and oxygen uptake during the freestyle repetitive lifting tasks. Moreover, the prediction metabolic cost model of the exoskeleton showed high accuracy as the absolute prediction errors were within 1.5%. In the third study, the biomechanical evaluation, energy expenditure and subjective assessments of two passive back-support exoskeletons (Laevo and SuitX) were examined in repetitive lifting tasks. The lifting tasks of this study were simulated in a laboratory environment for two different levels of lifting symmetry (symmetric vs. asymmetric) and lifting posture (standing vs. kneeling). Findings of this study showed that both exoskeleton significantly lowered the peak activity of back muscles during the dynamic lifting tasks. Moreover, using both exoskeletons provided metabolic cost savings in all of the studies conditions. Overall, results obtained from the three studies in this dissertation verified the capability of these passive lift- vi assistive exoskeleton in reducing the activity of back and leg muscles and providing the metabolic savings during repetitive lifting tasks.

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Pacientes lesados medulares frequentemente mencionam dores nos ombros, devido à elevada demanda dos membros superiores. Estes pacientes se submetem a diferentes tipos de reabilitação, no entanto é importante avaliar os métodos utilizados em tais programas para evitar possíveis prejuízos. O objetivo deste trabalho é avaliar o esforço e a atividade muscular dos ombros em pacientes paraplégicos caminhando com Estimulação Elétrica Neuro Muscular (EENM) e um andador em seções de reabilitação e comparar com duas atividades diárias executadas por estes indivíduos: propulsão da cadeira de rodas e elevação para alívio da pressão. Quinze homens adultos com paraplegia foram avaliados. Os movimentos em 3 dimensões foram obtidos com um sistema de 6 câmeras de infravermelho, e a atividade mioelétrica de 6 músculos dos ombros foi obtida bilateralmente por eletrodos de superfície ativos. Um andador instrumentalizado capturou a força durante a marcha, e a força nas outras duas atividades foi obtida por dinâmica inversa utilizando os dados cinemáticos e antropométricos. Os dados cinéticos e da atividade muscular foram avaliados estatisticamente utilizando análise de variância (ANOVA) e o teste das diferenças menos significativas de Tukey com nível de significância p<0,05. Foram obtidos picos de força quatro vezes maiores durante a marcha comparando-se à propulsão da cadeira de rodas. O esforço do ombro durante a marcha e a elevação foi equivalente, porém o lado direito durante a marcha apresentou maiores valores. O músculo mais ativo durante a marcha foi o tríceps, seguido pelo peitoral maior, deltóide anterior e trapézio inferior. A ação geral dos músculos durante a marcha também foi maior comparada aos outros exercícios executados. A marcha com EENM e andador, realizada por lesados medulares durante as seções de reabilitação, requer esforços significativos dos membros superiores, podendo gerar complicações nas articulações do ombro. Lesados medulares submetidos a seções de reabilitação que executam esforços significativos devem ser frequentemente monitorados, por métodos de ultra-som ou ressonância magnética, para evitar o comprometimento dos membros superiores e a consequente perda das funções de independência remanescentes / Spinal Cord Injured subjects often refer pain in their shoulders, due to the increased demand of the upper limbs. These subjects usually go through different rehabilitation strategies. Therefore, it becomes rather important to assess those methods in order to avoid further injuries to the patients. The goal of this work was to evaluate the shoulder effort and muscular activity in paraplegic subjects during gait with Neuromuscular Electrical Stimulation (NMES) with the aid of a walker and to compare it with two daily activities: wheelchair start up and weight relief raise. Fifteen adult male paraplegics were part of this study. The three-dimensional motions were acquired with six infrared cameras, and surface-active electrodes recorded the electromyography activity of 6 shoulder muscles, bilaterally. The vertical reaction force during walking was measured with a strain gauge instrumented walker, and the horizontal (wheelchair start-up) and vertical (weight relief raise) forces were obtained by inverse dynamics from kinematics and anthropometric data. The statistics of kinetic and electromyography data were done by analysis of variance (ANOVA) and the Tukey least significant differences post hoc test with significance level of p<0,05. Results have shown NMES gait force peaks being about four times higher than the values obtained for wheelchair start-up. The shoulder effort (force and torque) during walking and weight relief was similar, although the right side during NMES gait presented greater values. The triceps was the most active muscle during NMES walking, followed by pectoralis major, anterior deltoid and lower trapezius. The overall muscular activity during NMES walking was again higher than the other tasks executed. The NMES walking, when performed by spinal cord injured subjects can lead to injuries to the shoulder girdle. Due to the results obtained, continuous supervision of paraplegic upper limb effort should therefore be part of any rehabilitation center and for that ultrasound or magnetic resonance imaging may be recommended

La stimulation éléctrique fonctionnelle (SEF) peut améliorer de manière significative la mobilité des blessés médullaires ainsi que la stabilité et la prévention des effets secondaires. Dans le domaine de la SEF pour les membres inférieurs, le couple articulaire doit être fournie de façon appropriée pour effectuer le mouvement prévu afin de maintenir l'équilibre postural. Toutefois, les changements d'état du muscle telle que la fatigue musculaire est une cause majeure qui dégrade ses performances. En outre, la plupart des patients, dont la blessure médulaire est complète, n'ont pas le retour sensorielle qui permet de détecter la fatigue. De plus, et les capteurs de couples in-vivo ne sont pas disponibles à l'heure actuelle. Les systèmes conventionnels de commande SEF sont soit en boucle ouverte ou en boucle fermée mais cependant pas assez robustes aux changements d'état du muscle. L'objectif de cette thèse est le développement de la prédiction du couple articulaire et de la commande en boucle fermée afin d'améliorer les performances de la commande SEF en termes de précision, de robustesse et de sécurité pour les patients. Afin de prédire le couple articliare induit de la SEF, l'électromyographie (EMG) induit est utilisée pour corréler l'activité musculaire éléctrique et mécanique. Bien que la fatigue musculaire représente une variation dans le temps, une dépendance aux sujets et aux protocoles, la méthode proposée d'identification adaptative, basée sur le filtre de Kalman, est capable de prédire le couple articlaire variant dans le temps de manière systématique. La robustesse de la prédiction du couple articulaire a été evaluée lors d'une tâche de suivi de la fatigue en expérimentation chez des sujets blessés médullaires. Les résultats montrent une bonne performance de suivi des variations d'état des muscles en présence de fatigue et face à d'autres perturbations. Basée sur les performances de precision de la méthode prédictive proposée, une nouvelle stratégie de commande utilisant le retour EMG, "EMG-Feedback Predictive Control (EFPC)", est proposée afin de contrôler de manière adaptative les séquences de stimulation en compensant la variation dans le temps de l'état du muscle. De plus, cette stratégie de commande permet explicitement d'éviter d'appliquer une stimulation excessive aux patients, et de générer les séquences de stimulation appropriées pour obtenir la trajectoire désirée des couples articulaires.

Pacientes lesados medulares frequentemente mencionam dores nos ombros, devido à elevada demanda dos membros superiores. Estes pacientes se submetem a diferentes tipos de reabilitação, no entanto é importante avaliar os métodos utilizados em tais programas para evitar possíveis prejuízos. O objetivo deste trabalho é avaliar o esforço e a atividade muscular dos ombros em pacientes paraplégicos caminhando com Estimulação Elétrica Neuro Muscular (EENM) e um andador em seções de reabilitação e comparar com duas atividades diárias executadas por estes indivíduos: propulsão da cadeira de rodas e elevação para alívio da pressão. Quinze homens adultos com paraplegia foram avaliados. Os movimentos em 3 dimensões foram obtidos com um sistema de 6 câmeras de infravermelho, e a atividade mioelétrica de 6 músculos dos ombros foi obtida bilateralmente por eletrodos de superfície ativos. Um andador instrumentalizado capturou a força durante a marcha, e a força nas outras duas atividades foi obtida por dinâmica inversa utilizando os dados cinemáticos e antropométricos. Os dados cinéticos e da atividade muscular foram avaliados estatisticamente utilizando análise de variância (ANOVA) e o teste das diferenças menos significativas de Tukey com nível de significância p<0,05. Foram obtidos picos de força quatro vezes maiores durante a marcha comparando-se à propulsão da cadeira de rodas. O esforço do ombro durante a marcha e a elevação foi equivalente, porém o lado direito durante a marcha apresentou maiores valores. O músculo mais ativo durante a marcha foi o tríceps, seguido pelo peitoral maior, deltóide anterior e trapézio inferior. A ação geral dos músculos durante a marcha também foi maior comparada aos outros exercícios executados. A marcha com EENM e andador, realizada por lesados medulares durante as seções de reabilitação, requer esforços significativos dos membros superiores, podendo gerar complicações nas articulações do ombro. Lesados medulares submetidos a seções de reabilitação que executam esforços significativos devem ser frequentemente monitorados, por métodos de ultra-som ou ressonância magnética, para evitar o comprometimento dos membros superiores e a consequente perda das funções de independência remanescentes / Spinal Cord Injured subjects often refer pain in their shoulders, due to the increased demand of the upper limbs. These subjects usually go through different rehabilitation strategies. Therefore, it becomes rather important to assess those methods in order to avoid further injuries to the patients. The goal of this work was to evaluate the shoulder effort and muscular activity in paraplegic subjects during gait with Neuromuscular Electrical Stimulation (NMES) with the aid of a walker and to compare it with two daily activities: wheelchair start up and weight relief raise. Fifteen adult male paraplegics were part of this study. The three-dimensional motions were acquired with six infrared cameras, and surface-active electrodes recorded the electromyography activity of 6 shoulder muscles, bilaterally. The vertical reaction force during walking was measured with a strain gauge instrumented walker, and the horizontal (wheelchair start-up) and vertical (weight relief raise) forces were obtained by inverse dynamics from kinematics and anthropometric data. The statistics of kinetic and electromyography data were done by analysis of variance (ANOVA) and the Tukey least significant differences post hoc test with significance level of p<0,05. Results have shown NMES gait force peaks being about four times higher than the values obtained for wheelchair start-up. The shoulder effort (force and torque) during walking and weight relief was similar, although the right side during NMES gait presented greater values. The triceps was the most active muscle during NMES walking, followed by pectoralis major, anterior deltoid and lower trapezius. The overall muscular activity during NMES walking was again higher than the other tasks executed. The NMES walking, when performed by spinal cord injured subjects can lead to injuries to the shoulder girdle. Due to the results obtained, continuous supervision of paraplegic upper limb effort should therefore be part of any rehabilitation center and for that ultrasound or magnetic resonance imaging may be recommended

La stimulation électrique fonctionnelle (SEF) a le potentiel de fournir une amélioration active aux blessés médullaires en termes de mobilité, de stabilité et de prévention des effets secondaires.Dans le domaine des système SEF pour les membres inférieurs, le couple articulaire adéquat doit être fournie de façon appropriée pour effectuer le mouvement prévu et maintenir l'équilibre postural. Toutefois, les changements d'état du muscle tels que la fatigue musculaire est une cause majeure qui dégrade ses performances. En outre, la plupart des patients, dont la blessure médullaire est complète, n'ont pas le retour sensorielle qui permet de détecter la fatigue et les capteurs de couples in-vivo ne sont pas disponible à l'heure actuelle. Les systèmes conventionnels de commande SEF sont soit en boucle ouverte ou pas assez robustes aux changements d'état du muscle. L'objectif de cette thèse est le développement de la prédiction du couple articulaire et la commande en boucle fermée afin d'améliorer les performances de la commande SEF en termes de précision, de robustesse et de sécurité pour les patients.Afin de prédire le couple articulaire induit de la SEF, l'électromyographie (EMG) induit est utilisé pour corréler l'activité musculaire électrique et mécanique. Bien que la fatigue musculaire représente une variation dans le temps, une dépendance aux sujets et aux protocoles, la méthode proposée d'identification adaptative, basée sur le filtre de Kalman, est capable de prédire le couple articulaire variant dans le temps de manière systématique. La robustesse de la prédiction du couple articulaire a été évaluée lors d'une tâche de suivi de la fatigue en expérimentation chez des sujets blessés médulaires.Les résultats montrent une bonne performance de suivi des variations d'état des muscles en présence de fatigue et face à d'autres perturbations. Basé sur les performances de précision de la méthode prédictive proposée, une nouvelle stratégie de commande basée sur le retour EMG, «EMG-Feedback Predictive Control» (EFPC), est proposée afin de contrôler de manière adaptative les séquences de stimulation en compensant la variation dans le temps de l'état du muscle. De plus, cette stratégie de commande permet explicitement d'éviter d'appliquer une stimulation excessive aux patients, et de générer les séquences de stimulation appropriées pour obtenir la trajectoire désirée des couples articulaires. / Functional electrical stimulation (FES) has the potential to provide active improvement to spinal cord injured (SCI) patients in terms of mobility, stability and side-effect prevention. In the domain of lower limb FES system, elicited muscle force must be provided appropriately to perform intended movement and the torque generation by FES should be accurate not to lose the posture balance. However, muscle state changes such as muscle fatigue is a major cause which degrades its performance. In addition, most of the complete SCI patients don't have sensory feedback to detect the fatigue and in-vivo joint torque sensor is not available yet. Conventional FES control systems are either in open-loop or not robust to muscle state changes. This thesis aims at a development of joint torque prediction and feedback control in order to enhance the FES performance in terms of accuracy, robustness, and safety to the patients.In order to predict FES-induced joint torque, evoked-Electromyography (eEMG) has been applied to correlate muscle electrical activity and mechanical activity. Although muscle fatigue represents time-variant, subject-specific and protocol-specific characteristics, the proposed Kalman filter-based adaptive identification was able to predict the time-variant torque systematically. The robustness of the torque prediction has been investigated in a fatigue tracking task in experiment with SCI subjects. The results demonstrated good tracking performance for muscle variations and against some disturbances.Based on accurate predictive performance of the proposed method, a new control strategy, EMG-Feedback Predictive Control (EFPC), was proposed to adaptively control stimulation pattern compensating to time-varying muscle state changes. In addition, this control strategy was able to explicitly avoid overstimulation to the patients, and conveniently generate appropriate stimulation pattern for desired torque trajectory.

Title: The reflection kinesiology analyse of cross country skiing Purposes: To compare coordination of chosen muscles on leg during reflection of cross country skiing classic technique, skating and herringbone. Methods: Comparative analysis: the dates were measured by surface electromyography and 2-D video-analysis. Results: We founded statistical significance by comparisons muscle activation on right leg during kick during cross country skiing: classic technique, diagonal stride and herringbone and V-1 skating and herringbone. In case the left leg the statistical significance was disprove by: m. peroneus longus sin during comparison of diagonal stride and herringbone and m. gastrocnemius medialis sin V-1 skating and herringbone. We founded high level of laterality of diagonal stride and herringbone. In case V-1 skating, the significant similarity was not founded for m. vastus lateralis and m. gluteus medialis. Key words: Cross country skiing, classical technique, skating, herring bone, kinesiology, surface electromyography (EMG), muscles activation