Na literatura atual é consenso que o fornecimento de feedback extrínseco é um fator relevante para melhora do desempenho de indivíduos pós acidente vascular cerebral. Contudo, não é claro qual o melhor tipo de feedback extrínseco a ser fornecido para essa população. Tal fato está relacionado ás diferentes formas de frequência e momento de fornecimento de feedback apresentadas nos delineamentos heterogêneos dos estudos. Este trabalho procurou investigar os efeitos do tipo de feedback, conhecimento de performance (CP) e conhecimento de resultado (CR), fornecidos de forma igual em termos de momento e frequência na aprendizagem de uma habilidade motora em indivíduos pós-AVC. Participaram do estudo vinte indivíduos pós-AVC aleatorizados em dois grupos, dez indivíduos formaram o grupo experimental conhecimento de resultado (GECR) e dez indivíduos formaram o grupo experimental conhecimento de performance (GECP). Vinte indivíduos saudáveis pareados em idade com o grupo experimental (GE) foram recrutados para formação do grupo controle (GC). Todos os participantes realizaram movimentos de apontamento com o braço hemiparético em direção ao centro de um alvo exposto no ambiente virtual. Esse alvo possuía áreas de pontuação (AP) que variavam de 0 a 6 pontos. O GECR recebeu informação sobre a AP tocada e a pontuação atingida. O GECP recebeu informação relacionada a trajetória do movimento executado em direção ao centro do alvo. A fase de aquisição foi composta por três dias consecutivos de prática. A cada dia foram realizados 15 blocos de 5 tentativas, sendo a informação de feedback extrínseco emitida a todos os grupos em uma frequência sumária de 20%, na última tentativa de cada bloco. Após 4 dias foram realizados dois testes de retenção, cada um composto por um bloco de 5 tentativas sem emissão de feedback. As variáveis dependentes foram desempenho motor (pontuação) e padrão motor (tempo de movimento, pico de velocidade do dedo, linearidade, suavidade do movimento e ângulo de ombro por cotovelo). As variáveis dependentes foram comparadas entre os grupos (GE x GC) confrontando os dados do pré-teste, pós-teste, teste de retenção 1 e teste de retenção 2, por meio de uma Anova two way (4 grupos (GECP, GECR, GCCP, GCCR) x 4 testes (pré-teste, pós-teste, teste de retenção 1, teste de retenção 2), com medidas repetidas no fator testes, seguido do teste post hoc de Tukey. Os resultados revelaram que em relação ao desempenho motor (pontuação), apenas o GECR não aprendeu uma tarefa de apontamento. Não houve diferença entre GECP e GC. Em relação as variáveis de padrão motor GE e GC não apresentaram diferenças em relação ao tempo de movimento, contudo ambos os grupos demonstraram diminuição do pico de velocidade, melhora na linearidade do movimento e melhor coordenação interarticular. Em relação a variável suavidade o GECP apresentou pior desempenho através de maiores correções do movimento em relação ao GECR. Conclui-se que em indivíduos pós-AVC, o fornecimento de CP promoveu melhor comparado ao fornecimento de CR. Indivíduos pós-AVC que receberam CP aprenderam de forma semelhante a indivíduos saudáveis / In the current literature, it is agreed that the provision of extrinsic feedback is a relevant factor for improving the performance in stroke individuals. However, it is not clear which is the best type of extrinsic feedback to be provided for this population. This fact is related to the different forms of frequency and moment of feedback provided in the heterogeneous studies. This work searched to investigate the effects of the type of feedback knowledge of performance (KP) and knowledge of results (KR), in learning a motor skill at stroke individuals. Participated in the study Twenty stroke individuals were randomized into two groups, ten patients were designated to the Knowledge of Result Experimental Group (KREG) and ten individuals were designated to Knowledge of Performance Experimental Group (KPEG). Twenty healthy age-matched individuals with the experimental group (EG) were recruited for the control group (CG). All participants performed a pointing movement with the hemiparetic arm to the center of a target on a virtual environment. This target has scoring areas (SA) Varied from 0 to 6 points. The KREG received information about the SA reached and the score achieved. The KPEG received information related to the enpoint of movement performed to the center of the target. The acquisition phase was composed for three consecutive practice days. It were performed 15 blocks of 5 trials per day, and the extrinsic feedback information was provided to all groups at a summary frequency of 20%, in the last trial of each block. After 4 days, two retention tests were performed, each one composed of a block of 5 trials without feedback. The dependent variables were motor performance (score) and motor standard (movement time, peak finger speed, linearity, number of movement units (smoothness) and, elbow and shoulder angle). For analyses, it was performed an Anova two way (4 groups (KPEG, KREG, KPCG, KRCG) x 4 tests (pre-test, post-test, retention test 1, retention test 2), with repeated measures in the test factor, followed by Tukey post hoc test. The results revealed that in relation to motor performance, only the KREG did not learn a pointing task. There was not difference between KPEG and CG. Regarding the variables of motor pattern EG and CG did not present differences in relation to the time of movement, however, both groups showed a decrease in velocity peak, improvement in movement linearity and better interarticular coordination. In relation to the smoothness variable the KPEG presented worse performance through greater corrections of movement in relation to KREG. It was concluded that stroke individuals, the KP provision promoted better motor learning compared to KR delivery. Stroke individuals that received CP learned similarly from healthy individuals

O objetivo desse estudo foi verificar a mútua relação entre percepção de competência e aprendizagem motora. Para isso, 60 indivíduos entre 18 e 35 anos de idade, de ambos os sexos, inexperientes na habilidade forehand open space do tênis de campo foram divididos em três grupos de acordo com o preenchimento do questionário PSPP de percepção de competência: (1) alta percepção, (2) média percepção e (3) baixa percepção. Ainda, cada grupo foi subdividido de acordo com a possibilidade de controlar ou não uma determinada variável que afeta a aprendizagem motora, o estabelecimento de meta. Desta forma, os três grupos foram subdivididos em grupo escolha (auto-estabelecimento de meta) e grupo espelho (meta estabelecida pelo instrutor). A tarefa consistiu no forehand do tênis de campo com o objetivo de acertar um alvo redondo posicionado na quadra adversária. Foram três blocos de 20 tentativas durante três dias de aquisição e um teste de transferência, alterando a velocidade da bolinha, aplicado 10 minutos após o último bloco de tentativas da fase de aquisição. Os indivíduos preencheram o PSPP, todos os dias antes da prática e, no último dia antes e após a prática. Os resultados mostraram que a percepção de competência influenciou a aprendizagem motora de maneira que, indivíduos com alta percepção de competência aprenderam melhor que indivíduos de baixa percepção de competência. E, que o inverso não ocorreu, isto é, a aprendizagem motora não afetou a percepção de competência. Além disso, verificou-se que os grupos espelho obtiveram melhores desempenhos e superiores percepções de competência quando comparados aos grupos escolha / The aim of this study was to verify the mutual relationship between perceived competence and motor learning. For this purpose, 60 individuals between 18 and 35 years of age, of both sexes, inexperienced in the forehand open space skill of the tennis were divided into three groups according to the questionnaire PSPP of perceived competence: (1) high perception, (2) average perception and (3) low perception. Still, each group was subdivided by considering the possibility to control or not a particular variable that affects motor learning, the goal setting. Thus, they were divided into choice group (target of self-establishment) and yoked group (target set by the instructor). The task consisted in the forehand of the tennis field in order to hit a target positioned round the opponent\'s court. There were three blocks of 20 trials over three days of acquisition and a transfer test by changing the speed of the ball. This test was applied 10 minutes after the last block of trials of the acquisition phase. The participants answered the PSPP every day before the practice, and on the last day before and after practice. Results showed that the perception of competence influenced the motor learning so that individuals with high level of perceived competence learned better than those individuals with low levels of perceived competence. And, the inverse did not occur, i.e., motor learning did not affect the perception of competence. Furthermore, it was found that the yoked groups had better performances and higher levels of perceptions when compared to choice groups

O objetivo foi investigar a aquisição de habilidades motoras, no modelo do Processo Adaptativo, testando dois ciclos de Instabilidade-Estabilidade-Instabilidade (I-E-I). Duzentos e quarenta homens adultos jovens participaram de dois experimentos realizando uma tarefa seriada de rastreamento. As variáveis dependentes foram as respostas omissas, erradas, corretas e antecipatórias. O Experimento 1 testou o efeito dos Intervalos Inter-Estímulos (IIEs) em uma fase de aquisição num delineamento com seis grupos (300, 400, 500, 600, 700 e 800 ms de IIE); os testes estatísticos indicaram efeito de interação de grupos e blocos em todas as respostas. Com base nesses resultados foi elaborado o experimento principal com a mesma tarefa, num delineamento de três fases (Estabilização, Adaptação I e II) com o intuito de analisar o efeito dos ciclos I-E-I e dos IIEs no desempenho. Foram testados seis grupos nos quais os IIEs eram modificados de uma fase para outra. Os testes estatísticos mostraram efeito de interação entre grupos e blocos para os quatro tipos de resposta. Em seu conjunto, os resultados indicam que a aquisição de habilidades se dá mediante sucessivos ciclos de estabilização-adaptação, que leva ao aumento de complexidade; houve efeito do nível de estabilização alcançado no primeiro ciclo para o segundo ciclo de I-E-I e da magnitude da perturbação; a redundância inicial na estrutura teve efeito no desempenho em respostas funcionais ao longo dos ciclos / The aim of this study was to investigate the acquisition of motor learning as proposed by Adaptive Process model of motor learning by testing two Instability- Stability-Instability cycles (IN-ST-IN). Two hundred and forty young adult men participated in the two experiments in which a serial tracking task was used. The dependent variables were anticipatory, correct, incorrect and omission responses. The first experiment tested the effect of the Inter-Stimuli-Intervals (ISI) in an acquisition phase with a design comprised by six groups (300, 400, 500, 600, 700 e 800 ms of ISI); the MANOVA statistics (6 Groups X 3 Blocks) indicated interaction effect in all responses. Based on these results the main experiment was set up with a design of three phases (Stabilization, Adaptation I and II) with the aim to analyze the effect of the IN-ST-IN cycles and the ISIs on four responses. Six groups were tested in which the ISI were modified in each phase. The MANOVA statistics (6 Groups X 5 Blocks) indicated interaction effect in all responses. In sum, the results indicated that the acquisition process of motor skills takes place in the course of successive stabilization-adaptation cycles that lead to the increase to system\'s complexity; there was observed effect of the first cycle stabilization level on the second cycle; the early redundancy in the structure had effect on the functional responses performance, throughout the cycles

O presente estudo teve como objetivo avaliar o efeito de prática mental e sua associação com prática física na aprendizagem em uma tarefa envolvendo velocidade e precisão, em adolescentes com paralisia cerebral (PC) do tipo hemiparesia, comparando o efeito de lesões nos hemisférios cerebrais direito versus esquerdo. Participaram deste experimento 31 adolescentes com PC, os quais foram distribuídos em quatro grupos: (a) prática mental com hemiparesia direita, (b) prática mental com hemiparesia esquerda, e grupos controle com hemiparesia (c) direita ou (d) esquerda. A tarefa motora consistiu em tocar um alvo empregando o braço parético com demanda de precisão e rapidez. As sessões de prática foram divididas em dois dias. No primeiro dia, os grupos experimentais realizaram duas sessões de prática mental, sendo que cada sessão foi constituída de 5 blocos de 10 ensaios mentais. Os grupos controle realizaram nesta fase um jogo em microcomputador. No segundo dia, os grupos experimentais e controles receberam o mesmo tratamento, realizando prática física na tarefa. As avaliações motoras foram feitas imediatamente após as atividades do primeiro dia do experimento, e antes, imediatamente após e 30 min. após o fim da sessão de prática física. As análises dos resultados mostraram uma superioridade da prática mental em relação à prática física no tempo de movimento e índice de retidão. A prática física isolada apresentou superioridade na diminuição do deslocamento vertical da mão e na diminuição da quantidade de unidades de movimento. Os efeitos observados foram persistentes, indicando ganho de desempenho derivado de aprendizagem. Não houve diferença significante associada ao lado da lesão em nenhuma das variáveis analisadas. Os resultados do presente estudo revelaram que a prática mental foi efetiva em promover aprendizagem de forma equivalente entre indivíduos com lesão no hemisfério direito ou esquerdo / The present study aimed to evaluate the effect of mental practice on learning a task involving speed and accuracy in adolescents with hemiparethic cerebral palsy (CP), comparing the effect of lesions to the left versus right cerebral hemispheres. Participated in this experiment 31 CP adolescents who were assigned to four groups: (a) mental practice with right hemiparesis, (b) mental practice with left hemiparesis, and control groups with (c) right or (d) left hemiparesis. The motor task consisted of fast aiming at a target using the paretic arm. The practice sessions were divided into two days. On the first day, the experimental group held two sessions of mental practice, each session consisted of five blocks of 10 mental rehearsals. The control group played on a microcomputer game. On the second day, experimental and control groups received the same treatment, having physical practice on the task. Performance tests were made immediately after the activities of the first experimental session, and before, immediately after, and 30 min. after the end of the second session. Analysis of results showed a superiority of mental practice in relation to the physical practice in movement time and index of straightness. The physical practice alone was superior in reducing the vertical displacement of the hand and the decreased amount of units of movement. Those effects were persistent over time, indicating performance gains derived from learning. No significant differences associated with side of lesion were found. These results revealed that mental practice was effective in inducing learning similarly between individuals with lesions to the right or left cerebral hemispheres

The human central nervous system (CNS) is capable of significant architectural and physiological reorganization in response to environmental stimuli. Novel sensorimotor experiences stimulate neuronal networks to modify their intrinsic excitability and spatial connectivity within and between CNS structures. Early learning-induced adaptations in the primary motor cortex are thought to serve as a priming stimulus for long term CNS reorganization underlying long-lasting changes in motor skill. Recent animal and human studies suggest that whole body exercise and core temperature elevation as systemic stressors also recruit activity-dependent processes that prime the motor cortex, cerebellum, and hippocampus to process sensorimotor stimuli from the environment, enhancing overall CNS learning and performance. A primary goal of rehabilitation specialists is to evaluate and design activity-based intervention strategies that induce or enhance beneficial neuroplastic processes across the lifespan. As such, an investgation of the influence of physical, non-pharmacological interventions on cortical excitability, motor learning, and cognitive function provide the central theme of this dissertation. The first study investigated the effects of a visually-guided motor learning task on motor cortex excitability at rest and during voluntary activation measured via transcranical magnetic stimulation (TMS). Motor learning significantly increased resting cortical excitability that was not accompanied by changes in excitability as a function of voluntary muscle activation. The cortical silent period, a measure of inhibition, increased after learning and was associated with the magnitude of learning at low activation. These findings suggest that separate excitatory and inhibitory mechanisms may influence motor output as a function of learning success. The following studies investigated the influence of systemic whole-body thermal stress on motor cortex excitability, motor learning and cognitive performance. We established the reliability of a novel TMS cortical mapping procedure to study neurophysiological responses after whole-body heat stress. Heat stress significantly potentiated motor cortex excitability, though acute motor learning and cognitive test performance did not differ between subjects receiving heat stress and control subjects. Future research is needed to delineate the potential of whole body heat stress as a therapeutic modality to influence central nervous system plasticity and performance.

Clinicians working on motor skill learning interventions often find that improvements observed during training are not sustained and do not transfer to very similar tasks. Research suggests that strategies such as real-time biofeedback and learner's focus of attention seem to facilitate motor skill learning. However, research on the implications of these strategies in rehabilitation is limited and has not been investigated in healthy individuals. The motor learning effects of these strategies need to be assessed as they offer the possibility of enhancing rehabilitation regimens. The purpose of this study was to investigate the generalizability of real-time biofeedback and learner's focus of attention to a treadmill gait retraining program aimed at correcting knee hyperextension insidious gait patterns in healthy young women. Assessing the acquisition, retention, and transfer of kinematic improvements was the focus of this study. 1.Knee sagittal plane kinematics could be influenced with dynamic gait training using real-time biofeedback. Gained proficiency in controlling knee hyperextension during treadmill training was evident during overground walking immediately and 1 month after training. 2.The effectiveness of real-time biofeedback in improving performance does not seem to be influenced by the focus of attention, internal or external, induced during treadmill training. Participants in both intervention groups improved in a similar way as a consequence of practice. However, there were trends in the data that pointed that the external focus of attention group had better long-term retention. It is not known if participants actively switched to an external focus of attention despite the instructions provided during training. Tests to ensure instructional compliance should be used. 3.A treadmill gait retraining program using learner's focus of attention indicated that that there were not differences in learning acquisition, short and long-term retention, and transfer to overground walking and obstacle crossing between intervention groups. It is not known if these changes persist beyond the 4-month follow-up included in this study. The results of this study will help to reduce knee hyperextension gait patterns in women. Future studies may also use the methodology used in this study to further investigate the implications of learner's focus of attention in rehabilitation. Similarly, the findings of this study could offer an additional strategy for rehabilitation regimens.

Upper body control is required to complete many daily tasks. One needs to stabilize the head and trunk over the pelvis, as one shifts the center of mass to interact with the world. While healthy individuals can perform activities that require leaning, reaching, and grasping readily, those with neurological and musculoskeletal disorders present with control deficits. These deficits can lead to difficulty in shifting the body center of mass away from the stable midline, leading to functional limitations and a decline in the quality of activity. Often these patient groups use canes, walkers, and wheelchairs for support, leading to occasional strapping or joint locking of the body for trunk stabilization. Current rehabilitation strategies focus on isolated components of stability. This includes strengthening, isometric exercises, hand-eye coordination tasks, isolated movement, and proprioceptive training. Although all these components are evidence based and directly correlate to better stability, motor learning theories such as those by Nikolai Bernstein, suggest that task and context specific training can lead to better outcomes. In specific, based on our experimentation, we believe functional postural exploration, while encompassing aspects of strengthening, hand-eye coordination, and proprioceptive feedback can provide better results. In this work, we present two novel cable robotic platforms for seated and standing posture training. The Trunk Support Trainer (TruST) is a platform for seated posture rehabilitation that provides controlled external wrench on the human trunk in any direction in real-time. The Stand Trainer is a platform for standing posture rehabilitation that can control the trunk, pelvis, and knees, simultaneously. The system works through the use of novel force-field algorithms that are modular and user-specific. The control uses an assist-as-needed strategy to apply forces on the user during regions of postural instability. The device also allows perturbations for postural reactive training. We have conducted several studies using healthy adult populations and pilot studies on patient groups including cerebral palsy, cerebellar ataxia, and spinal cord injury. We propose new training methods that incorporate motor learning theory and objective interventions for improving posture control. We identify novel methods to characterize posture in form of the “8-point star test”. This is to assess the postural workspace. We also demonstrate novel methods for functional training of posture and balance. Our results show that training with our robotic platforms can change the trunk kinematics. Specifically, healthy adults are able to translate the trunk further and rotate the trunk more anteriorly in the seated position. In the standing position, they can alter their reach strategy to maintain the upper trunk more vertically while reaching. Similarly, Cerebral Palsy patients improve their trunk translations, reaching workspace, and maintain a more vertical posture after training, in the seated position. Our results also showed that an Ataxia patient was able to improve their reaching workspace and trunk translations in the standing position. Finally, our results show that the robotic platforms can successfully reduce trunk and pelvis sway in spinal cord injury patients. The results of the pilot studies suggest that training with our robotic platforms and methods is beneficial in improving trunk control.

This thesis describes three boys diagnosed with dyspraxia and their whanau (families and extended families) as they enter and become part of a community gymnastics group in a city in New Zealand. The study builds on literature that has defined dyspraxia in terms of dysfunction, but generally failed to resolve the disorder. Through the social perspective of health and well-being, participation of children and adults with disabilities has been explored in terms of the person and the environments in which they participate; however, the influence activity itself has on participation has not been thoroughly described. There has been a growing interest in the participation of children with disabilities in recreation and leisure activities and this study provides an in depth cultural perspective of such participation in New Zealand context. This study aims to answer the question "What do children with dyspraxia and their whanau do in a gymnastics group, and what does it mean to them to participate?". The overarching question is "What is the culture of a community gymnastics group in which children with dyspraxia participate?". Ethnographic methodology is employed to ensure that the participants' perspectives, including the beliefs, values and meaning that their participation holds is portrayed, while the associated activities and behaviours are also captured. As the boys with dyspraxia and their whanau entered the gym, they built on their previous experiences to make sense of what they needed to do and what meaning the environment held. I had not planned on the boys being integrated with an established group, but on the first night they spontaneously joined in with a noncompetitive, mixed age, boys group. The parents perceived the Club as professional, while the boys were initially intimidated. Fortunately, the equipment, which made the gym look like a playground, enticed the boys to participate. To shift the boys from their initial perception of the gym being a playground, the coaches used two styles of An Ethnography of Children with Dyspraxia Participating in Gymnastics coaching to support and encourage their participation, while suppressing behaviour that did not fit with the norms of the Club. The boys needed to develop gymnastics skills and fit into the group to become gymnasts. The boys succeeded in fitting into the group by both developing skills and adapting their behaviour, while the type of boys without dyspraxia, the style of coaching afforded, the range of equipment and the activity of gymnastics itself meant that some of their initial difficulties were accommodated and they were seen as group members. The participants developed values and beliefs about what the boys participation in the group meant. Having fun and developing confidence and fitness were highlighted, while the social aspects (making friends and the whanau experiences) were also seen as important. The parents and coaches felt that the boys' experiences in gymnastics had an impact on them that would transfer to the world beyond the gym. This study contributes a qualitative perspective on the participation of children with disabilities in a sports occupation, with a focus on the cultural context of their participation.

The objects with which the hand interacts with may significantly change the dynamics of the arm. How does the brain adapt control of arm movements to this new dynamic? We show that adaptation is via composition of a model of the task's dynamics. By exploring generalization capabilities of this adaptation we infer some of the properties of the computational elements with which the brain formed this model: the elements have broad receptive fields and encode the learned dynamics as a map structured in an intrinsic coordinate system closely related to the geometry of the skeletomusculature. The low--level nature of these elements suggests that they may represent asset of primitives with which a movement is represented in the CNS.

In their challenge-point framework (CPF) Guadagnoli and Lee’s (2004) argue that learning is maximized when a person faces an optimal level of challenge during practice. It is suggested that challenge level can be manipulated through the combination of different practice variables. The purpose of this study was to investigate how practice schedule and self-controlled feedback frequency manipulations affect performance and learning of motor skills. Participants (n=96) attempted to learn three versions of a key-pressing task. The task consisted of pressing five computer keys in specified sequences in a goal criterion time. Participants were assigned to either a blocked practice schedule with self-controlled feedback (BLK-SC), a random practice schedule with self-controlled feedback (RND-SC), a blocked practice schedule with yoked feedback (BLK-YK), a random practice schedule with yoked feedback (RND-YK), a blocked practice schedule and 100 percent feedback (BLK-100), or a random practice schedule with 100 percent feedback (RND-100). Participants in the blocked conditions practiced 30 trials of each task according to a blocked practice schedule. Participants in the random conditions practiced 30 trial of each task according to a random practice schedule. Participants in the self-controlled feedback condition were allowed to choose whether or not to receive feedback on each trial. Yoked participants had their feedback schedule matched to a participant with similar characteristics in the self-control condition. Participants in the 100% feedback condition received feedback after every trial. Participants were also asked to complete the NASA Task Load Index (Hart & Staveland, 1988) and an adapted Perceived Competence for Learning scale (adapted from Williams & Deci, 1996) after the completion of the 5th and 90th trial. After 24 hr participants performed a retention test. The results indicated no difference between groups during retention or for the NASA-TLX and PCL scores. The feedback frequency analysis indicated no differences between BLK-SC and RND-SC groups. In general, the findings of the present study show that the effects of practice schedule conditions can be offset by self-controlled feedback manipulations. They also suggest that a number of different combinations of practice schedules and feedback frequencies can lead to similar challenge levels.