Influence of the diabetic neuropathy on the behavior of electromyographic and sensorial responses in treadmill gait.

OBJECTIVE: We describe and interpret self-cadence treadmill walking by neuropathic diabetic subjects under biomechanical and somatosensorial considerations. DESIGN: EMG variables during stance phase of neuropathic diabetic subjects were acquired and analyzed. We also evaluated sensorial and motor aspects of the feet and legs. METHODS: The experimental procedures are divided as follows: (a) determination of the sensitive cronaxie and pain tolerance in selected plantar areas, (b) determination and description of temporal aspects of EMG patterns of the vastus lateralis, tibialis anterior and lateral gastrocnemius of both sides during treadmill walking. We analyze and compare the results of the sensitive cronaxie, pain tolerance and the EMG parameters obtained by two experimental groups: diabetic neuropathic (n=20) and non-diabetic control subjects (n=20). RESULTS: The somatosensorial responses and pain tolerance threshold in the diabetic neuropathic group were significantly higher and considered far from the normal patterns. The EMG responses of the thigh and leg muscles in the diabetic neuropathic group were delayed if compared to the normal recruitment pattern, especially the tibialis anterior and vastus lateralis. CONCLUSIONS: These findings lead us to conclude that probably central and/or peripheral control mechanisms of the gait of neuropathic diabetic patients are altered due to somatosensorial and motor deficits. The mechanism of load reduction during walking was considered inefficient because of the activation delay of the vastus lateralis and tibialis anterior. We have concluded that the peripheral diabetic neuropathy damages not only somatosensorial and motor sources but also intrinsic mechanisms of motor control leading to alterations in the ankle efficiency in gait. This resulting distal inefficiency compromises some of the principal requirements for gait, such as progression and balance. RELEVANCE: This investigation is based on an innovating thematic approach involving the diabetic peripheral neuropathy. This innovation concerns the use of EMG and an instrumented treadmill in a clinical application to study and interpret the motor control during gait in neuropathic diabetic patients.

Analise biomecanica da locomocao de individuos com e sem lesao no ligamento cruzado anterior: um estudo de caso / Biomechanics parameters for the analysis of locomotion pattern in subject presenting Anterior Cruciate Ligament injury

A lesao do Ligamento Cruzado Anterior(LCA) influencia os mecanismo funcionais da articulacao do joelho,por intermedio de processos adaptativos ainda nao muito claros. O objetivo do presente estudo foi identificar as alteracoes biomecanicas da locomocao devido a lesao do LCA em um estudo de caso. Foram analisadas a atividade eletrica dos musculos vasto lateral, vasto medial e biceps da coxa, a forca de reacao do solo, a variacao angular e o momento de forca da articulacao do joelho durante a fase de apoio do andar. Foram estudados um sujeito com lesao do LCA e um sujeito sem nenhuma difusao musculo-esqueletica. Os resultados indicam a presenca de mecanismo compensatorios de reducao do momento de forca interno extensor no inicio da fase de apoio do andar, que corrobora com o aumento da atividade eletromiografica do musculo biceps da coxa nessa fase

On the inter- and intra-subject variability of the electromyographic signal in isometric contractions.

The objective of the present study was to evaluate the variability of the surface EMG signal of the same muscle in healthy subjects, because of lack of reproducibility of the EMG signal for the same subject and muscle in different trials of maximal isometric voluntary contraction. The results showed an EMG coefficient of variability of 21.61%, indicating that this variability must be considered in experiments with an inappropriate condition for normalization procedures, such as EMG biofeedback in rehabilitation sessions, or normalization procedures by the maximal isometric voluntary contraction.

Comparative study of Mm. Multifidi in lumbar and thoracic spine.

Imbalance of Mm. Multifidi may play a role in spinal disorders such as scoliosis in the thoracic spine, and lumbar disc herniation and lower back pain in the lumbar spine. Even though changes in these muscles are related to the etiology of these disorders, their anatomy is still poorly understood, especially in the upper regions of the spine. With the aim of gaining a better understanding of the anatomy of Mm. Multifidi in the lumbar and thoracic spine, 12 fresh and two embalmed cadavers were dissected. Our results indicate that Mm. Multifidi present differences in lumbar and thoracic spines concerning their deepness, fibre trajectory, muscle length, muscle mass and tendinous tissue. In the lumbar spine Mm. Multifidi are a superficial, thick and fleshy mass, and their fibres are more vertical in relation to the spinous processes. In the thoracic spine Mm. Multifidi are deeper, thinner, and their fibres are more tendinous and oblique than in the lumbar spine. These differences have implications on Mm. Multifidi architecture and consequently for their function in these two regions of the spine.

A study of biomechanical parameters in gait analysis and sensitive cronaxie of diabetic neuropathic patients.

OBJECTIVE: The present investigation aims at studying the sensitive cronaxie in neuropathic and non-neuropathic diabetic patients as a measure of sensorial deficit. We seek to describe the gait using dynamic and temporal parameters. We have compared the results of the neuropathic patients to the results of a non-diabetic group. We have looked for relationships between peak plantar pressure and sensitive cronaxie in selected plantar areas. DESIGN AND METHODS: The experimental procedures were divided in: (a) determination of the sensitive cronaxie in four selected plantar areas, (b) determination and description of peak plantar pressure, ground reaction force variables and single and double stance time. We analyzed and compared the results of the sensitive cronaxie and the biomechanical parameters obtained by three experimental groups: diabetic, neuropathic and non-diabetic subjects. RESULTS: The pathological response of the sensitive cronaxie worsened progressively for neuropathic and diabetic patients, respectively. Longer double and single stance times, lower minimum vertical force and lower growth rates were seen in the neuropathic patients when compared to diabetic and non-diabetic subjects. CONCLUSIONS: These results indicate an alteration in the neuropathic patient movement structure. We have speculated that compensatory musculoskeletal mechanisms have been developed by neuropathic patients to compensate for their sensorial deficit. Future research is necessary to verify the relationship between neurophysiological and dynamic variables, since this relationship seems to be a good parameter for the interpretation and comprehension of the peripheral neuropathy. RelevancePeripheral neuropathy is one of the most insidious chronic complications of diabetes. It has been observed that dynamic changes in gait are usually associated with the peripheral neuropathy somatosensory deficits. Biomechanical studies have highlighted that dynamic gait evaluation can identify functional alterations, besides the analysis of sensitive cronaxie as a measure of sensorial deficits. They are also useful as a complimentary routine in the clinic treatment of diabetes and its further long-term complications.

Comportamento adaptativo de funçöes neuro-musculares e cinéticas selecionadas em diferentes tarefas locomotoras / Adaptative behavior of neuromuscular function and selected kinets in different locomotor methods

O movimento humano requer controle e coordenação simultâneos entre diversos segmentos corporais e, para tanto, o sistema motor elabora estratégias neuro-musculares e fiom de reduzir os graus de liberdade. Uma maneira de se investigar a flexibilidade e adaptabilidade do sistema motor e através do estudo biomecânico de padrões de movimentos submetidos a diferentes demandas ambientais. Assim, este estudo propõe-se a avaliar respostas eletromiográficas dos principais músculos locomotores, bem como a componente vertical da força reação do solo durante o andar no plano, subindo e descendo escadas em crianças. Através da análise do comportamento adaptativo destes parâmetros neuro-musculares e cinéticos, pode-se obter indicadores quantitativos e qualitativos da função coordenativa do sistema motor

Abstract - The human movement is dependent on the contrai of multiple coordinations and the motor system elaborates neuro-muscular strategies to reduce the degrees of freedom of multi-joint movements. A way to investigate the flexibility and adaptability characteristics of the motor system is through the biomechanical study of movement patterns submitted to different environmental constraints. The purpose of this study is to analyse the electromyographic activity of locomotor muscles and the vertical componente ofthe ground reaction force in children during levei and stair walking. Through the analysis of the adaptative behavior of these selected neuromuscular and kinetic parameters, it is possible to identify qualitative and quantitative indicators of the coordinative function ofthe human motor system