Variação da atividade elétrica entre o repouso e a máxima contração voluntária dos músculos masseteres em homens adultos / Variation of electrical activity between rest and maximum voluntary contraction of masseter muscles in adult men / Variación de la actividad eléctrica entre el descanso y la contracción voluntaria máxima de los músculos maseteros en hombres adultos

Introdução: A eletromiografia de superfície (EMGs) é um exame objetivo, indolor, não invasivo e de fácil aplicação utilizado para avaliar as atividades elétricas de determinado músculo ou grupo muscular durante a máxima contração voluntária, repouso e dinâmica funcional. Objetivo: Comparar a variação do potencial elétrico dos músculos masseteres entre o repouso e máxima contração voluntária em indivíduos com faixas etárias diferentes. Método: A pesquisa foi aprovada em comitê de ética e executada na Clínica Escola do Departamento de Fonoaudiologia da Universidade Federal de Sergipe obedecendo aos rigores éticos e de biossegurança. A amostra foi composta por 26 adultos sem queixas orofaciais, sexo masculino e idade variando entre 26 e 42 anos, divididos em Grupo 1 e Grupo 2, os quais assinaram um termo de consentimento livre e esclarecido concordando com a participação na pesquisa. Os voluntários foram submetidos à avaliação eletromiográfica dos músculos masseteres durante o repouso e máxima contração voluntária. Resultados: Houve uma diminuição da atividade elétrica do masseter quando se comparou o G1 com o G2, porém não foi observada uma linearidade desse declínio ao analisar o universo estudado. Por isso, deve-se levar em consideração que o envelhecimento é um processo fisiológico particular de cada ser, sendo influenciado por múltiplos fatores intrínsecos e extrínsecos ao organismo. Observou-se, também, que no repouso nenhum indivíduo teve absolutamente 0 nos seus registros eletromiográficos, caracterizando um estado basal de atividade elétrica para garantia do tônus. Conclusão: Foi verificado que os voluntários com 30 anos ou mais apresentaram um declínio nos potenciais mioelétricos e, possivelmente, um déficit de força associado.

Introduction: Surface electromyography (EMGs) is an objective, painless, non-invasive and easily applied test used to assess the electrical activities of a particular muscle or muscle group during maximum voluntary contraction, rest and functional dynamics. Objective: Compare the variation in the electrical potential of the masseter muscles between rest and maximum voluntary contraction in individuals with different age groups. Method: The research was approved by the ethics committee and carried out at the Clínica Escola of the department of Speech, Language and Hearing Sciences at the Federal University of Sergipe, obeying ethical and biosafety rigors. The sample consisted of 26 adults without orofacial complaints, male with age from 26 to 42 years old, divided into Group 1 and Group 2, who signed a consent form agreeing to participate in the research. The volunteers underwent electromyographic evaluation of the masseter muscles during rest and maximum voluntary contraction. Results: There was a decrease in the electrical activity of the masseter when comparing G1 to G2; however, there was no linearity of this decline when analyzing the universe studied. Therefore, it must be taken into account that aging is a particular physiological process of each individual, being influenced by multiple factors, intrinsic and extrinsic to the organism. It was also observed at rest, no individual had absolutely 0 in their electromyographic records, characterizing a baseline state of electrical activity to guarantee tone. Conclusion: It was found that volunteers aged 30 years or more showed a decline in myoelectric potentials and possibly an associated strength deficit.

Introducción: Electromiografía de superficie (EMG) es una prueba objetiva, indolora, no invasiva y de fácil aplicación que se utiliza para evaluar actividades eléctricas de un músculo o grupo muscular en particular durante la contracción voluntaria máxima, el reposo y la dinámica funcional. Objetivo: Comparar la variación del potencial eléctrico de los maseteros entre reposo y contracción voluntaria máxima en individuos de diferentes grupos de edad. Método: La investigación fue aprobada por el comité de ética y realizada en la Clínica Escola del departamento de logopedia de la Universidad Federal de Sergipe obedeciendo rigores éticos y de bioseguridad. La muestra estuvo conformada por 26 adultos sin quejas orofaciales, varones y edades comprendidas entre 26 y 42 años dividido en Grupo 1 y Grupo 2, quienes firmaron formulario de consentimiento aceptando participar en la investigación. Los voluntarios se sometieron a evaluación electromiográfica de los músculos maseteros durante reposo y la máxima contracción voluntaria. Resultados: Hubo disminución en la actividad eléctrica del masetero cuando se comparó G1 con G2, sin embargo no hubo linealidad de esta disminución al analizar el universo estudiado. Por tanto, hay que tener en cuenta que el envejecimiento es proceso fisiológico particular de cada ser, siendo influenciado por múltiples factores intrínsecos y extrínsecos al organismo. También se observó que en reposo ningún individuo tenía absolutamente 0 en sus registros electromiográficos, caracterizando estado basal de actividad eléctrica para garantizar el tono. Conclusión: Se encontró que los voluntarios de 30 años o más mostraron una disminución en los potenciales mioeléctricos y posiblemente un déficit de fuerza asociado.

Effects of ankle exoskeleton assistance during human walking on lower limb muscle contractions and coordination patterns / 生物医学工程学杂志

Lower limb ankle exoskeletons have been used to improve walking efficiency and assist the elderly and patients with motor dysfunction in daily activities or rehabilitation training, while the assistance patterns may influence the wearer's lower limb muscle activities and coordination patterns. In this paper, we aim to evaluate the effects of different ankle exoskeleton assistance patterns on wearer's lower limb muscle activities and coordination patterns. A tethered ankle exoskeleton with nine assistance patterns that combined with differenet actuation timing values and torque magnitude levels was used to assist human walking. Lower limb muscle surface electromyography signals were collected from 7 participants walking on a treadmill at a speed of 1.25 m/s. Results showed that the soleus muscle activities were significantly reduced during assisted walking. In one assistance pattern with peak time in 49% of stride and peak torque at 0.7 N·m/kg, the soleus muscle activity was decreased by (38.5 ± 10.8)%. Compared with actuation timing, the assistance torque magnitude had a more significant influence on soleus muscle activity. In all assistance patterns, the eight lower limb muscle activities could be decomposed to five basic muscle synergies. The muscle synergies changed little under assistance with appropriate actuation timing and torque magnitude. Besides, co-contraction indexs of soleus and tibialis anterior, rectus femoris and semitendinosus under exoskeleton assistance were higher than normal walking. Our results are expected to help to understand how healthy wearers adjust their neuromuscular control mechanisms to adapt to different exoskeleton assistance patterns, and provide reference to select appropriate assistance to improve walking efficiency.

Rate of force development and stretch-shortening cycle in different jumps in the elite volleyball players / Tasa de desarrollo de fuerza y ciclo de estiramiento-acortamiento en diferentes saltos en jugadores de voleibol de élite

SUMMARY: As it is currently played, volleyball is a game in which success depends in large measure on the athleticism of the participants. The aim of this research was to point out the importance of the cycle of stretching and shortening in different jumps for elite volleyball players. Thus, it is common for volleyball athletes to place considerable emphasis on jump training. Not surprisingly, overload injuries of the knee and ankle joints, both acute and chronic, occur frequently among volleyball players and are related to the volume of jump training and skill repetition. Understanding the biomechanics of jumping is therefore a prerequisite for designing effective training programs which minimize the risk of overuse injuries that may result from excessive jumping, and the repetitive mechanical loading of muscles and joints that are involved in jump training Muscles acting about a joint function naturally through a combination of eccentric (lengthening) and concentric (shortening) activations. In the lower limb, the stretch-shortening cycle is a reflex arc in which the tendomuscular system acting about the knee or ankle is eccentrically preloaded (stretched) in the loading or impact phase of the jump before concentrically shortening in the push-off or take-off phase.

RESUMEN: Actualmente, el voleibol es un juego en el que el éxito depende en gran medida del atletismo de los participantes. El objetivo de esta investigación fue señalar la importancia del ciclo de estiramiento y acortamiento en diferentes saltos para jugadores de voleibol de élite. Es común que los atletas de voleibol pongan un énfasis considerable en el entrenamiento de salto. No es sorprendente que las lesiones por sobrecarga de las articulaciones de la rodilla y el tobillo, tanto agudas como crónicas, ocurran con frecuencia entre los jugadores de voleibol y estén relacionadas con el volumen de entrenamiento de saltos y la repetición de destrezas. Comprender la biomecánica del salto es, por lo tanto, un requisito previo para diseñar programas de entrenamiento efectivos que minimicen el riesgo de lesiones por uso excesivo que pueden resultar de un salto excesivo y la carga mecánica repetitiva de los músculos y las articulaciones que están involucrados en el entrenamiento del salto. Los músculos que actúan sobre una articulación funcionan de forma natural a través de una combinación de activaciones excéntricas (alargamiento) y concéntricas (acortamiento). En el miembro inferior, el ciclo de estiramiento-acortamiento es un arco reflejo en el que el sistema tendomuscular que actúa sobre la rodilla o el tobillo se precarga (estira) excéntricamente en la fase de carga o impacto del salto antes de acortarse concéntricamente en el despegue o toma. -fase de apagado.

Força muscular do assoalho pélvico em mulheres com queixas de disfunção pélvica / Pelvic floor muscle strength in women with pelvic dysfunction complaint

A disfunção do assoalho pélvico envolve condições nosológicas, como incontinência urinária e disfunção sexual, com impacto negativo na qualidade de vida. O presente estudo objetivou avaliar a força muscular do assoalho pélvico de mulheres com disfunção pélvica. Trata-se de desenho analítico transversal realizado com uma amostra de conveniência de 167 mulheres com queixas de disfunções musculares do assoalho pélvico. Foram analisadas características sociodemográficas e clínicas, qualidade de vida relacionada à incontinência e força muscular pélvica. Estatísticas univariadas e bivariadas foram calculadas. A idade média das mulheres foi de 50,2 anos. A maioria foi classificada com impacto muito grave (76,6%) na qualidade de vida relacionada à incontinência, 41 (24,6%) apresentaram contração muscular não sustentada e 7 (4,2%) apresentaram contração. Associações significativas foram identificadas entre força muscular pélvica e idade (p = 0,025), menopausa (p = 0,039) e histerectomia (p = 0,026). A pesquisa permitiu concluir que os fatores de risco responsáveis por problemas no assoalho pélvico podem ser considerados cruciais para avaliar o nível de impacto da incontinência urinária e sua evolução como resultado de intervenções precoces, simples e de baixo custo na atenção primária à saúde. As disfunções do assoalho pélvico afetam negativa e substancialmente a qualidade de vida das mulheres. (AU)

Pelvic floor dysfunction involves nosological conditions, such as urinary incontinence and sexual dysfunction, which have a negative impact on quality of life. This study aimed to evaluate pelvic floor muscle strength of women with pelvic dysfunction. This is an analytical cross-sectional performed design with a convenience sample of 167 women with complaints of pelvic floor muscle dysfunctions. Sociodemographic and clinical characteristics, quality of life related to incontinence and pelvic muscle strength were analyzed. Univariate and bivariate statistics were calculated. The mean age of women was 50.2 years. Most were classified having a very severe impact (76.6%) on incontinencerelated quality of life, 41 (24.6%) presented non-sustained muscle contraction and 7 (4.2%) presented in contraction. Significant associations were identified between pelvic muscle strength and age (p = 0.025), menopause (p = 0.039) and hysterectomy (p = 0.026). This study allowed us to conclude that the risk factors responsible for pelvic floor problems can be considered crucial to assess the level of impact of urinary incontinence and its evolution as a result of early, simple and low cost interventions in primary health care. Pelvic floor dysfunctions affect negatively and substantially the quality of life of women. (AU)

Enhanced active contraction of the transversus abdominis during walking / Aumento de la contracción activa del músculo transverso del abdomen durante la caminata / Aumento da contração ativa do músculo transverso do abdome durante a caminhada

ABSTRACT Introduction: We applied three-dimensional gait analysis to assess the effects of enhanced active contraction of the transversus abdominis (EACTA) during walking. We sought to evaluate the effect of EACTA during walking in order to improve walking quality. Methods: Thirty college students were recruited and trained to perform EACTA during walking. We examined gait parameters under different conditions, including EACTA and habitual ACTA (natural walking with mild contraction of the feedforward mechanism of ACTA, HACTA) during walking using three-dimensional gait analysis. We compared differences in gait parameters under the two walking conditions using SPSS 16.0 statistical software. Results: The following gait parameters were significantly lower under EACTA conditions than under HACTA conditions (P < 0.05): stance phase, 59.151% ± 1.903% vs. 59.825% ± 1.495%; stride time, 1.104 s ± 0.080 s vs. 1.134 s ± 0.073 s:; stance time, 0.656 s ± 0.057 s vs. 0.678 s ± 0.053 s; and swing time, 0.447 s ± 0.028 s vs. 0.454 s ± 0.031 s, respectively. Gait parameters single support phase and mean velocity were significantly higher for EACTA than for HACTA conditions (both P < 0.05). Conclusions: Overall, the results revealed that EACTA during walking can improve gait. This method is simple, and EACTA training during walking to improve gait quality in daily life could provide a positive basis for people to strengthen the transverse abdominal muscle. Level of evidence III; Retrospective comparative study .

RESUMEN Introducción: Aplicamos el análisis tridimensional de la marcha para evaluar los efectos del aumento de la contracción activa del músculo transverso del abdomen (EACTA) durante la caminata. Buscamos evaluar el efecto del EACTA durante la caminata para mejorar su calidad. Métodos: Treinta estudiantes universitarios fueron reclutados y entrenados para realizar el EACTA durante la caminata. Examinamos los parámetros de la marcha en diferentes condiciones, incluyendo EACTA y ACTA habitual (caminata natural con leve contracción del mecanismo de feedforward del ACTA, HACTA) durante la caminata usando análisis tridimensional de la marcha. Comparamos las diferencias en los parámetros de la marcha en las dos condiciones de caminata en el software estadístico SPSS 16.0. Resultados: Los siguientes parámetros de marcha fueron significativamente más bajos en la condición EACTA que en condiciones HACTA (P <0,05): fase de apoyo 59,151 ± 1,903% vs 59,825 ± 1,495%, tiempo de zancada 1,104 s ± 0,080 s vs 1,134 s ± 0,073 s, tiempo de apoyo 0,656 s ± 0,057 s vs 0,678 s ± 0,053 s y tiempo de balance 0,447 s ± 0,028 s vs 0,454 s ± 0,031 s, respectivamente. Los parámetros de la marcha, fase de apoyo simple y velocidad promedio fueron significativamente mayores en el EACTA que en las condiciones HACTA (ambos P <0,05). Conclusiones: En general, los resultados revelaron que el EACTA durante la caminata puede mejorar la marcha. Este método es simple, y el entrenamiento del EACTA durante la caminata para mejorar la calidad de la marcha en la vida diaria puede ser una base positiva para el fortalecimiento del músculo transverso del abdomen. Nivel de evidencia III; Estudio retrospectivo comparativo .

RESUMO Introdução: Aplicamos a análise tridimensional da marcha para avaliar os efeitos do aumento da contração ativa do músculo transverso do abdome (EACTA) durante a caminhada. Procuramos avaliar o efeito do EACTA durante a caminhada para melhorar sua qualidade. Métodos: Trinta estudantes universitários foram recrutados e treinados para realizar o EACTA durante a caminhada. Examinamos os parâmetros da marcha em diferentes condições, incluindo EACTA e ACTA habitual (caminhada natural com leve contração do mecanismo de feedforward do ACTA, HACTA) durante a caminhada usando análise tridimensional da marcha. Comparamos as diferenças nos parâmetros da marcha nas duas condições de caminhada no software estatístico SPSS 16.0. Resultados: Os seguintes parâmetros da marcha foram significativamente mais baixos na condição EACTA do que em condições HACTA (P < 0,05): fase de apoio 59,151 ± 1,903% vs. 59,825 ± 1,495%, tempo de passada 1,104 s ± 0,080 s vs. 1,134 s ± 0,073 s, tempo de apoio 0,656 s ± 0,057 s vs. 0,678 s ± 0,053 s e tempo de balanço 0,447 s ± 0,028 s vs. 0,454 s ± 0,031 s, respectivamente. Os parâmetros da marcha fase de apoio simples e velocidade média foram significativamente maiores no EACTA do que nas condições HACTA (ambos P < 0,05). Conclusões: No geral, os resultados revelaram que o EACTA durante a caminhada pode melhorar a marcha. Esse método é simples, e o treinamento do EACTA durante a caminhada para melhorar a qualidade da marcha na vida diária pode ser uma base positiva para o fortalecimento do músculo transverso do abdome. Nível de evidência III; Estudo retrospectivo comparativo .

Pelvic floor muscles after prostate radiation therapy: morpho-functional assessment by magnetic resonance imaging, surface electromyography and digital anal palpation

ABSTRACT Aim: To evaluate the radiotherapy (RT) effect in the pelvic floor muscles (PFM) function in men with prostate cancer (PC). Materials and Methods: A cross-sectional study included three groups of patients with PC and RT indication: 1) Pre-RT group: evaluated before the beginning of RT; 2) Acute group: evaluated between six months and one year after RT; 3) Late Group: evaluated between two and a half years and four years post-RT. PFM assessment was divided into: a) functional assessment through the digital anal palpation (Modified Oxford Scale) and surface electromyography (sEMG) with anal probe; b) anatomical assessment by pelvic magnetic resonance imaging (MRI) with thickness measurements of levator ani muscle and pelvic specific parameters at rest and under Valsalva maneuver. We used Student t test, considering as significant p <0.05. Results: Thirty-three men were assessed: Pre-RT (n=12); Acute (n=10) and Late (n=11) groups. PFM functional assessment showed Late group with lower electromyographic activity, especially in the sustained contractions when compared to the Pre-RT (p=0.003) and Acute groups (p=0.006). There was no significant difference between groups in MRI. Conclusion: PFM functional assessment showed a decrease in sEMG activity in the Late group post-RT. Most of the sample (72.7%) did not know how to actively contract the PFM or had a weak voluntary contraction when assessed by digital anal palpation. Also, these patients presented higher prevalence of pelvic complaints. No changes were observed in the morpho-functional parameters evaluated by MRI, except the measurement of the membranous urethra length when comparing Pre-RT Group and Acute and Late Groups.

Reliability of a simple novel field test for the measurement of plantar flexor muscle strength / Confiabilidade de um novo teste de campo simples para medir a força dos músculos flexores plantares / Confiabilidad de un nuevo test de campo simple para medir la fuerza de los músculos flexores plantares

ABSTRACT Introduction When a person is in a standing position, the plantar flexor muscles are involved in most static and dynamic body movements. Objectives The aim of this study was to investigate the trial to trial and factorial reliability of measuring the contractile characteristics of PF muscles using a simple novel field test. Methods The sample consisted of 452 healthy subjects, 120 male and 332 female. The research was conducted by means of the trial to trial testing method, using isometric dynamometry performed in field conditions. ANOVA was used to estimate the differences among the trials, Cronbach's alpha and interclass correlation to estimate the correlations among the trials, and principal component analysis to evaluate the contribution of each trial to overall variability. Results The main findings of this study are that trials differed significantly (p<0.000) for maximal force (Fmax) and maximal rate of force development (RFDmax), indicating that the three procedural trials were necessary. The trials were highly correlated (Fmax, RFDmax, r>0.9), proving that measuring was reliable, and the factorial analysis separated the second and third trials, the second trial accounting for most of the total variability. Conclusions The simple novel field test for the measurement of plantar flexor contractile characteristics recommended by this study proved to be as highly reliable as laboratory testing, but was easy to perform in conditions outside of scientific or diagnostic institutions, which greatly facilitates the work of scientists, coaches and professionals. Level of Evidence II; Diagnostic Studies - Investigating a diagnostics test.

RESUMO Introdução Quando uma pessoa está em pé, os músculos flexores plantares são envolvidos na maioria dos movimentos corporais estáticos e dinâmicos. Objetivos O objetivo deste estudo foi investigar a confiabilidade teste-reteste e fatorial da mensuração das características contráteis dos músculos plantares, usando um novo teste de campo simples. Métodos A amostra consistiu em 452 indivíduos saudáveis, 120 homens e 332 mulheres. O estudo foi realizado pelo método de teste-reteste, com dinamometria isométrica conduzida em condições de campo. Empregou-se a ANOVA para estimar a diferença entre os testes o alfa de Cronbach e a correlação interclasse para estimar a correlação entre os testes e análise de componentes principais , para avaliar a contribuição de cada teste para a variabilidade global. Resultados Os principais achados deste estudo são que os testes diferiram significativamente (p < 0,000) para a força máxima (Fmáx) e a taxa máxima de desenvolvimento de força (TDFmáx), indicando que os três testes de procedimento foram necessários. Os testes foram altamente correlacionados (Fmáx, TDFmáx, r > 0,9), provando que a medição era confiável, e a análise fatorial separou o segundo e o terceiro testes, sendo que o segundo teste apresentou a maior parte da variabilidade total. Conclusões O novo teste de campo simples para medição das características contráteis dos flexores plantares recomendado por este estudo provou ser tão confiável quanto os testes de laboratório e, ao mesmo tempo, mais fácil de realizar fora das instituições científicas ou de diagnóstico, o que facilita muito o trabalho de cientistas, treinadores e profissionais. Nível de Evidência II; Estudos Diagnósticos - Investigação de um exame para diagnóstico.

RESUMEN Introducción Cuando una persona está de pie, los músculos flexores plantares son involucrados en la mayoría de los movimientos corporales estáticos y dinámicos. Objetivos El objetivo de este estudio fue investigar la confiabilidad test-retest y factorial de la medición de las características contráctiles de los músculos plantares, usando un nuevo test de campo simple. Métodos La muestra consistió en 452 individuos saludables, 120 hombres y 332 mujeres. El estudio fue realizado a través del método de test-retest, con dinamometría isométrica conducida en condiciones de campo. Se empleó ANOVA para estimar la diferencia entre los tests, alpha de Crombach y la correlación interclase para estimar la correlación entre los tests y el análisis de componentes principales, para evaluar la contribución de cada test para la variabilidad global. Resultados Los principales hallazgos de este estudio son que los tests difirieron significativamente (p<0,000) para la fuerza máxima (Fmáx) y la tasa máxima de desarrollo de fuerza (TDFmáx) indicando que los tres tests de procedimiento fueron necesarios. Los tests fueron altamente correlacionados (Fmáx, TDFmáx, r>0,9) probando que la medición era confiable, y el análisis factorial separó el segundo y tercer test, siendo que el segundo test presentó la mayor parte de variabilidad total. Conclusiones El nuevo test de campo simple para medición de las características contráctiles de los flexores plantares recomendado por este estudio probó ser tan confiable como los tests de laboratorio y, al mismo tiempo, más fácil de realizar fuera de las instituciones científicas o de diagnóstico, lo que facilita mucho el trabajo de científicos, entrenadores y profesionales. Nivel de evidencia II; Estudios diagnósticos - Investigación de un examen para diagnóstico.

A new method for high-density surface electromyography decomposition in dynamic muscle contraction / 生物医学工程学杂志

In this paper, a new surface electromyography (sEMG) signal decomposition method based on spatial location is proposed for the high-density sEMG signals in dynamic muscle contraction. Firstly, according to the waveform correlation of each muscle motor units (MU) in each channel, the firing times are extracted, and then the firing times are classified by the spatial location of MU. The MU firing trains are finally obtained. The simulation results show that the accuracy rate of a single MU firing train after classification is more than 91.67%. For real sEMG signals, the accuracy rate to find a same MU by the "two source" method is over (88.3 ± 2.1)%. This paper provides a new idea for dynamic sEMG signal decomposition.

The effects of active vs. passive recovery on riding performance during a simulated motocross race

Abstract Aims: Motocross consists of two races of 30 min with a break in between. Recovery between races is paramount to performance, this study aimed to compare the effects of active and passive recovery between motocross races on riding performance. Methods: Thirteen elite and non-elite racers performed two races of 30 min with 1 h break, twice with two-week interval. Between the races active (20 min ergometer cycling at 60% of HRmax) or passive recovery (no activity) were executed in a randomized order. Lap times, heart rate during riding, blood lactate, reaction time, handgrip strength, upper back pull strength, counter movement jump height, and medicine ball throw distance were measured before and after both races. Serum creatine kinase enzyme activity and strength tests were assessed also 24 h after the races. Results: No statistically significant differences were observed in any variables between protocols. A significant drop in handgrip strength was found post-race values (p < 0.001). Post-racing creatine kinase values were above resting levels. Conclusion: These results do not support the use of active recovery in between motocross races for restoration of neuromuscular or riding performance. Motocross seems to cause some exercise-induced muscle damage; thus, some rest is required to recover homeostasis.

Characterization of electrocorticographic, electromyographic and electrocardiographic recordings after the use of caffeine in Wistar rats / Caracterização dos registros eletrocorticográficos, eletromiográficos e eletrocardiográficos após uso de cafeína em ratos Wistar

ABSTRACT Objective: To describe electrocorticographic, electromyographic and electrocardiographic profiles to report the electrophysiological effects of caffeine in Wistar rats. Methods: Male adult Wistar rats weighing 230g to 250g were used. Rats were allocated to one of two groups, as follows: Group 1, Control, intraperitoneal injection of 0.9% saline solution (n=27); and Group 2, treated with intraperitoneal injection of caffeine (50mg/kg; n=27). The rats were submitted to electrocorticographic, electromyographic and electrocardiographic assessment. Results: Brain oscillations (delta, theta, alpha, beta and gamma) in the frequency range up to 40Hz varied after caffeine administration to rats. Powers in delta and theta oscillations ranges were preponderant. The contractile force of the skeletal striated and cardiac muscles increased. Electrocardiogram analysis revealed shorter RR, QRS and QT intervals under the effect of caffeine. Conclusion: In the central nervous system, there was an increase in the delta, theta and alpha amplitude spectrum, which are related to memory encoding and enhanced learning. With regard to skeletal muscle, increased contraction of the gastrocnemius muscle was demonstrated, a clear indication of how caffeine can be used to enhance performance of some physical activities. Electrocardiographic changes observed after caffeine administration are primarily related to increased heart rate and energy consumption.

RESUMO Objetivo: Descrever os perfis eletrocorticográficos, eletromiográficos e eletrocardiográficos para relatar os efeitos eletrofisiológicos da cafeína em ratos Wistar. Métodos: Foram utilizados ratos Wistar, machos, adultos, pesando de 230g a 250g. Os animais foram divididos nos seguintes grupos: Grupo 1, Controle com solução fisiológica 0,9% por via intraperitoneal (n=27), e Grupo 2, Tratado com Cafeína (50mg/kg intraperitoneal; n=27). Foram realizadas avaliações por eletrocorticograma, eletromiograma e eletrocardiograma. Resultados: Houve variações nas oscilações cerebrais (delta, teta, alfa, beta e gama) na faixa de frequência de até 40Hz após a aplicação de cafeína em ratos. Observou-se que as potências nas faixas das oscilações delta e teta foram preponderantes. A força de contração nos músculos estriado esquelético e cardíaco aumentou. A avaliação do eletrocardiograma demonstrou que a duração dos intervalos RR, QRS e QT foram menores na presença da cafeína. Conclusão: No sistema nervoso central, houve aumento dos espectros de amplitude delta, teta e alfa, que auxiliam na codificação das memórias e estão relacionados à melhora do aprendizado. Em relação à musculatura esquelética, demonstrou-se aumento da contração do músculo gastrocnêmio, uma clara indicação de como a cafeína pode ser usada para aumentar o desempenho em algumas atividades físicas. As alterações eletrocardiográficas observadas após a administração de cafeína estiveram relacionadas principalmente ao aumento da frequência cardíaca e do consumo de energia.

Evaluation of Lateral Pterygoid Muscle Contraction in Patients with Temporomandibular Disorders Based on 3D-T2 Weighted Imaging / 中国医学科学院学报

Objective To evaluate lateral pterygoid muscle(LPM)contraction in the patients with temporomandibular disorders(TMD)based on 3D-T2 weighted imaging(3D-T2WI).Multiplanar reconstruction(MPR)was employed to measure the length of LPM in the images taken in closed-and open-mouth positions. Methods Seventeen TMD patients [age of(29.82±10.70)years,males/females=8/9] and 13 normal volunteers [control,age of(23.54±3.31)years,males/females=6/7] received 3D-T2WI of the temporomandibular joints in closed-and open-mouth positions from November 2019 to April 2020 in Department of Radiology,Hainan Hospital of Chinese PLA General Hospital.According to the position of the discs,the subjects were classified into the following groups:TMD with disc displacement without reduction(TMD-DDwoR),TMD with disc displacement with reduction(TMD-DDwR),TMD without disc displacement(TMDwoDD),and normal control without disc displacement(NCwoDD).MPR was employed to measure the maximal length of the superior belly of LPM.One-way analysis of variance,receiver operating characteristic curve,and permutation test were employed for the statistical analyses. Results The contraction of LPM was significantly shorter in TMD-DDwoR group [(3.36±1.96)mm] than in TMDwoDD group [(7.90±3.95)mm],NCwoDD group [(8.77±3.13)mm](

Torque estimation based on surface electromyography: potential tool for knee rehabilitation / Estimación de par basada en electromiografía de superficie: potencial herramienta para la rehabilitación de rodilla

Abstract Introduction: Multiple signal processing studies have reported the application of surface electromyography (sEMG) signals in robotics and motor rehabilitation processes. Objective: To conduct a literature review on the use of sEMG signals as an alternative method for knee torque estimation in order to objectively measure the progress of patients at different stages of knee injury rehabilitation. Materials and methods: A literature review of studies published between 1986 and 2018, without geographical limits, was carried out in the Engineering Village, IEEE Xplore, Science-Direct, Web of Science, Scopus, and PubMed databases by combining 8 search terms. Results: After completing the initial search, 355 records were retrieved. Duplicated publications were eliminated, and 308 articles were analyzed to determine if they met the inclusion criteria. Finally, 18 studies describing, in a comparative way, how to estimate torque based on sEMG signals were included. Conclusion: The use of sEMG signals to calculate joint torque is an alternative method that allows therapists to obtain quantitative parameters and assess the progress of patients undergoing knee rehabilitation processes.

Resumen Introducción. Múltiples estudios de procesamiento de señales han reportado la aplicación de las señales de electromiografía de superficie (sEMG) en robótica y en procesos de rehabilitación motora. Objetivo. Realizar una revisión de la literatura sobre el uso de señales de sEMG como alternativa para la estimación del par de rodilla con el fin de medir objetivamente el progreso de los pacientes en las diferentes etapas de rehabilitación de lesiones de rodilla. Materiales y métodos. Se realizó una revisión de la literatura publicada entre 1986 y 2018, sin límites geográficos, en las bases de datos Engineering Village, IEEE Xplore, ScienceDirect, Web of Science, Scopus y PubMed mediante la combinación de 8 términos de búsqueda. Resultados. Al finalizar la búsqueda inicial se obtuvieron 355 registros. Luego de realizar la remoción de duplicados esta cifra descendió a 308, los cuales fueron analizados para determinar si cumplían con los criterios de inclusión. Finalmente se incluyeron 18 estudios que describen de forma comparativa cómo estimar el par a partir de señales de sEMG. Conclusión. El uso de señales de sEMG para calcular el par en una articulación es una herramienta alternativa que permite al terapeuta acceder a parámetros cuantitativos y, de esta forma, valorar el progreso de los pacientes durante el proceso de rehabilitación de rodilla.

Avaliação da força muscular dos membros superiores através dinamometro hand held: estudo piloto / Evaluation of muscular strength of the upper limbs through dynamometer hand held: pilot study

Introdução: a avaliação de componentes físicos é importante para a estratificação da capacidade funcional de um indivíduo. A contração muscular gerada por encurtamento das unidades contráteis do músculo, promovendo força muscular. Objetivos: descrever um protocolo de avaliação da força muscular periférica dos membros superiores (MMSS) através do dinamômetro Hand Held (DHH), assim como testar, em estudo piloto, o instrumento e o protocolo de coleta propostos. Metodologia: trata-se de um estudo piloto, de caráter descritivo, de corte transversal, que expõe e aplica o protocolo de avaliação da força muscular periférica de MMSS em indivíduos saudáveis. A amostra foi composta por voluntários saudáveis, com idade entre 18 e 80 anos, que assinaram o termo de consentimento livre e esclarecido (TCLE). Foi testada a contração isométrica para os principais movimentos das maiores articulações dos MMSS superior do membro de dominância. A pesquisa foi aprovada pelo comitê de ética em pesquisa do ICS/UFBA, parecer n°1537948. Os dados qualitativos foram expostos em frequência absoluta e relativa, e os dados quantitativos expressos em média e desvio padrão e (ou) mínimo e máximo. Foi realizada a correlação de Pearson entre o torque dos flexores do cotovelo com variáveis antropométricas escalares. Resultado: a amostra foi composta por 16 voluntários, com idade entre 20 e 40 anos, predominância do sexo feminino (62,5%), IMC médio 23,7 (4,8), fisicamente ativos (68,8%). A mensuração do torque demonstrou maiores torques flexores de cotovelo, rotadores internos de ombro, extensores de punho e extensores de ombro. Conclusão: o protocolo demonstrouse prático e factível, com tempo de mensuração médio de 30 minutos. Não foram observados eventos adversos conhecidos durante as avaliações.

Introduction: t evaluation of physical components is important for the stratification of an individual's functional capacity. The muscle contraction generated by shortening of the contractile units of the muscle, promoting muscle strength. Objectives: to describe a protocol for the assessment of upper limb muscle strength (MMSS) using the Hand Held Dynamometer (DHH), as well as to test the proposed instrument and collection protocol in a pilot study. Methodology this is a descriptive, cross-sectional, pilot study that exposes and applies the protocol for the evaluation of peripheral muscle strength of MMSS in healthy individuals. The sample consisted of healthy volunteers, aged between 18 and 80 years, who signed the informed consent form (TCLE). We tested the isometric contraction for the major movements of the major joints of the superior MMSS of the dominance limb. The research was approved by the research ethics committee of ICS / UFBA, opinion n1537948. The qualitative data were exposed in absolute and relative frequency, and the quantitative data expressed in mean and standard deviation and (or) minimum and maximum. The Pearson correlation between the torque of the elbow flexors and scalar anthropometric variables was performed. Results: the sample consisted of 16 volunteers, aged between 20 and 40 years, predominantly female (62.5%), mean BMI 23.7 (4.8), physically active (68.8%). Torque measurement showed greater elbow flexor torques, internal rotators of the shoulder, wrist extensors, and shoulder extensors. Conclusion: the protocol proved to be practical and feasible, with an average measurement time of 30 minutes. No known adverse events were observed during the assessments.

Concurrent validity of the static and dynamic measures of inspiratory muscle strength: comparison between maximal inspiratory pressure and s-index

Abstract Objective: To verify the concurrent validity between the inspiratory muscle strength (IMS) values obtained in static (maximal inspiratory pressure [MIP]) and dynamic (S-Index) assessments. Methods: Healthy individuals were submitted to two periods of evaluation: i) MIP, static maneuver to obtain IMS, determined by the Mueller's maneuver from residual volume (RV) until total lung capacity (TLC); ii) and S-Index, inspiration against open airway starting from RV until TLC. Both measures were performed by the same evaluator and the subjects received the same instructions. Isolated maneuvers with differences < 10% were considered as reproducible measures. Results: Data from 45 subjects (21 males) were analyzed and that showed statistical difference between MIP and S-Index values (133.5 ± 33.3 and 125.6 ± 32.2 in cmH2O, respectively), with P=0.014. Linear regression showed r2=0.54 and S-Index prediction formula = 39.8+(0.75×MIP). Pearson's correlation demonstrated a strong and significant association between the measures with r=0.74. The measurements showed good concordance evidenced by the Bland-Altman test. Conclusion: S-Index and MIP do not present similar values since they are evaluations of different events of the muscular contraction. However, they have a strong correlation and good agreement, which indicate that both are able to evaluate the IMS of healthy individuals.

Síndrome de persona rígida, presentación de un caso clínico y actualidad en el tratamiento / Stiff person syndrome, presentation of a clinical case and an update on the treatment

RESUMEN El síndrome de persona rígida afecta el sistema nervioso central. Los signos clínicos relevantes son la rigidez, los espasmos musculares y sensibilidad incrementada a los estímulos externos, que inducen las contracciones musculares. Las mujeres son afectadas de 2 a 3 veces más con relación a los hombres. Hay marcadores de tipo clínico y electrofisiológico característicos. La etiología se asocia con la mediación por anticuerpos y puede ser la expresión de un síndrome paraneoplásico. El tratamiento farmacológico se realiza con medicamentos relajantes musculares y medicamentos con mecanismo inmunomodulador o inmunosupresor. Adicionalmente, se requiere un plan complementario de rehabilitación. El propósito del grupo es hacer una descripción del caso clínico, que consideramos es relevante por su baja frecuencia de presentación y realizar una actualización sobre el tema.

A B S T R A C T Stiff person syndrome affects the central nervous system. Relevant clinical signs are stiffness, muscle spasms, increased sensitivity with external stimuli that increase muscle contractions. Women are affected twice to three times more, in comparation with the men. There are characteristic clinical and electrophysiological type markers. The etiology is associated with mediation by antibodies and may be the expression of a paraneoplastic syndrome. Pharmacological treatment is focused on muscle relaxant-type medications, drugs with immunomodulatory or immunosuppressive mechanism. In adition, complementary rehabilitation treatment is required. The purpose of the group is to make the description of the clinical case that is relevant due to the low frequency of presentation and to carry out an update of the topic.

Bilateral Femoral Neck Fracture Secondary to Seizure: Treatment with Total Hip Arthroplasty by the Direct Anterior approach / Fratura bilateral do colo do fêmur secundária a crise convulsiva: Tratamento com artroplastia total do quadril pelo acesso anterior direto

Abstract Bilateral fracture of the femoral neck secondary to seizure is a rare event. The occurrence of these lesions is related to vigorous tonic-clonic muscular contractions and to the use of anticonvulsive medications. Femoral neck fractures in young adults treated with total hip arthroplasty are the exception, and the choice of surgical access should consider several factors; the direct anterior approach is a possibility for total hip arthroplasty. The authors present the case of a 36-year-old male with bilateral fracture of the femoral neck secondary to seizure, and in regular use of phenytoin. Due to the risk of fixation failure and prolonged evolution time, bilateral total hip arthroplasty was the procedure of choice. The choice of the approach should take into consideration the patient's anatomy, material availability, and surgeon's experience. Thus, the greater ease of preparation and positioning of the patient, the shorter hospital stay, the early postoperative rehabilitation, and the mastery of the technique by the surgeon, are possible justifications for the adoption of the direct anterior approach.

Resumo A fratura bilateral do colo do fêmur secundária à crise convulsiva é um evento raro. A ocorrência dessas lesões está relacionada a contrações musculares tônico-clônicas vigorosas e ao uso de medicações anticonvulsivantes. As fraturas do colo do fêmur no adulto jovem tratadas com artroplastia total do quadril são exceção, e a escolha do acesso cirúrgico deve levar em consideração diversos fatores; o acesso anterior direto é uma possibilidade para artroplastia total do quadril. Os autores apresentam o caso de um homem de 36 anos com fratura bilateral do colo do fêmur secundária a crise convulsiva e em uso regular de fenitoína. Devido ao risco de falha da fixação e ao tempo de evolução prolongado, optou-se pela artroplastia total do quadril bilateral. A escolha da via de acesso deve levar em consideração a anatomia do paciente, a disponibilidade de materiais e a experiência do cirurgião. Dessa forma, a maior facilidade de preparo e posicionamento do paciente, o menor tempo de internação, a reabilitação pós-operatória precoce e o domínio da técnica pelo cirurgião são possíveis justificativas para a adoção do acesso anterior direto.

La rigidez cadavérica, el espasmo cadavérico y tipos de fibras musculares / The cadaveric rigidity, the cadaveric spasm and types of muscle fibers

La rigidez cadavérica (rigor mortis) es un proceso no muy bien comprendido por la mayoría de los médicos. El conocimiento de la intimidad del proceso de la rigidez cadavérica es de vital importancia ya que es una de las variables que junto con las livideces (livor mortis) y la temperatura (algor mortis) del cadáver ayudan a determinar el cronotanatodiagnóstico, tanatocronodiagnóstico o intervalo postmortal del período inmediato de la muerte. Para entender el mecanismo de la rigidez y el espasmo cadavérico es preciso hacer un repaso de la contracción muscular fisiológica en el vivo. Hay que tener presente que el tipo de fibra muscular predominante modificará las características de la contracción muscular fisiológica en el vivo, y también la rigidez y el espasmo cadavérico. (AU)

The cadaveric rigidity (rigor mortis) is a process which is not very well understood by the majority of the doctors. The knowledge of the intimacy of the cadaveric stiffness process is of vital importance since it is one of the variables that, as well as the postmortem lividity (livor mortis) and the body temperature post mortem (algor mortis) help determine the chronotanatodiagnostic, tanatochronodiagnostic or postmortal interval of the immediate period of death. In order to understand the mechanism of stiffness and cadaveric spasm, it is necessary to review the physiological muscle contraction in vivo. We should keep in mind that the predominant type of muscle fiber will modify the characteristics of physiological muscle contraction in vivo, as well as stiffness and cadaveric spasm. (AU)

Oximetría, Frecuencia Cardíaca, Apnea y Actividad de los Músculos Masticatorios en Sujetos con BS / Oximetry, Heart Rate, Apnea and Mastication Muscle Activity in Subjects with Sleep Bruxism

RESUMEN: El objectivo de este estudio fue describir los valores promedio de oximetría, frecuencia cardíaca y eventos de apnea durante la noche y la actividad de los músculos maseteros y temporales en un grupo de adultos jóvenes con BS. Estudio observacional descriptivo de serie de casos que consideró una muestra 20 jóvenes entre 21 y 25 años diagnosticados con BS mediante polisomnografía. Se describieron las condiciones de actividad de los músculos maseteros y temporales mediante electromiografía y los valores e los signos vitales mediante polisomnografía. El análisis estadístico fue de tipo descriptivo, se aplicaron medidas de tendencia central, frecuencias absolutas y relativas. El promedio de la actividad muscular durante la masticación de los maseteros fue (D: 86) (I: 520). El promedio de la actividad muscular durante la masticación de los temporales fue (D: 340) (I: 510). El promedio en los episodios de hipopnea fue de (28,9). El promedio de oximetría fue (NMOR: 93,5) (MOR: 93,8). El promedio de la tasa cardiaca fue (NMOR: 65,4) (MOR: 66,8) latidos/minuto. El promedio de eventos de bruxismo fue (NREM: 135,4) (REM: 120,2).y el índice (eventos BS/hora) (40,60). Las características de las musculares masticatorias y los signos vitales durante el sueño de los sujetos con BS pueden ayudar al entendimiento y a la toma de decisiones en el tratamiento.

ABSTRACT: The objective of the study was to describe the average oximetry, heart rate, and apnea events values during sleep, and the activity of masseter and temporal muscles in a group of young adults with SB (Sleep Bruxism). This serial case and observational descriptive study comprised of a sample of 20 young people between 21 and 25 years of age, who were diagnosed with SB through a polysomnography test. Electromyography recordings served to describe the activity conditions of masseter and temporal muscles, while polysomnography was used to obtain measurement values and vital signs. A descriptive statistical analysis accounting for measures of central tendency, absolute and relative frequencies was performed. During mastication, the average masseter and temporal muscle activity values registered at (D: 86) (I: 520), and (D: 340) (I: 510) respectively. While, the average value for hypopnea episodes was (28.9), and (NREM: 93.5) (REM: 93.8) for oximetry. The average heart rate exhibited a value of (NREM: 65.4) (REM: 66.8) beats / minute, while the values for bruxism events registered at (NREM: 135.4) (REM: 120.2) with an index value of (SB events / hour) (40.60). Muscles of mastication characteristics, and vital signs during sleep for subjects with SB can aid in understanding and decision making in treatment.

Melatonin protects against myocardial ischemia-reperfusion injury by inhibiting contracture in isolated rat hearts / 浙江大学学报·医学版

OBJECTIVE@#To investigate the protective effect of melatonin against myocardial ischemia reperfusion (IR) injury in isolated rat hearts and explore the underlying mechanisms.@*METHODS@#The isolated hearts from 40 male SD rats were randomly divided into 4 groups (=10): the control group, where the hearts were perfused with KH solution for 175 min; IR group, where the hearts were subjected to global ischemia for 45 min followed by reperfusion for 120 min; IR+melatonin (Mel+IR) group, where melatonin (5 μmol/L) was administered to the hearts 1 min before ischemia and during the first 5 min of reperfusion, followed by 115 min of reperfusion; and IR+2, 3-butanedione monoxime (IR+BDM) group, where the hearts were treated with BDM (20 mmol/L) in the same manner as melatonin treatment. Myocardial injury in the isolated hearts was assessed based on myocardial injury area, caspase-3 activity, and expressions of cytochrome C and cleaved caspase-3 proteins. Cardiac contracture was assessed using HE staining and by detecting lactate dehydrogenase (LDH) activity and the content of cardiac troponin I (cTnI) in the coronary outflow, measurement of left ventricular end-diastolic pressure (LVEDP) and electron microscopy. The content of ATP in the cardiac tissue was also determined.@*RESULTS@#Compared with those in the control group, the isolated hearts in IR group showed significantly larger myocardial injury area and higher caspase-3 activity and the protein expressions of cytochrome C and cleaved caspase-3 with significantly increased LDH activity and cTnI content in the coronary outflow and elevated LVEDP at the end of reperfusion; HE staining showed obvious fractures of the myocardial fibers and the content of ATP was significantly decreased in the cardiac tissue; electron microscopy revealed the development of contraction bands. In the isolated hearts with IR, treatment with Mel or BDM significantly reduced the myocardial injury area, caspase-3 activity, and protein expressions of cytochrome C and cleaved caspase-3, obviously inhibited LDH activity, lowered the content of cTnI and LVEDP, reduced myocardial fiber fracture, and increased ATP content in the cardiac tissue. Both Mel and BDM inhibited the formation of contraction bands in the isolated hearts with IR injury.@*CONCLUSIONS@#Mel can alleviate myocardial IR injury in isolated rat hearts by inhibiting cardiac contracture, the mechanism of which may involve the upregulation of ATP in the cardiac myocytes to lessen the tear of membrane and reduce cell content leakage.

Intermuscular coupling based on wavelet packet-cross frequency coherence / 生物医学工程学杂志

Human motion control system has a high degree of nonlinear characteristics. Through quantitative evaluation of the nonlinear coupling strength between surface electromyogram (sEMG) signals, we can get the functional state of the muscles related to the movement, and then explore the mechanism of human motion control. In this paper, wavelet packet decomposition and : coherence analysis are combined to construct an intermuscular cross-frequency coupling analysis model based on wavelet packet- : coherence. In the elbow flexion and extension state with 30% maximum voluntary contraction force (MVC), sEMG signals of 20 healthy adults were collected. Firstly, the subband components were obtained based on wavelet packet decomposition, and then the : coherence of subband signals was calculated to analyze the coupling characteristics between muscles. The results show that the linear coupling strength (frequency ratio 1:1) of the cooperative and antagonistic pairs is higher than that of the nonlinear coupling (frequency ratio 1:2, 2:1 and 1:3, 3:1) under the elbow flexion motion of 30% MVC; the coupling strength decreases with the increase of frequency ratio for the intermuscular nonlinear coupling, and there is no significant difference between the frequency ratio : and : . The intermuscular coupling in beta and gamma bands is mainly reflected in the linear coupling (1:1), nonlinear coupling of low frequency ratio (1:2, 2:1) between synergetic pair and the linear coupling between antagonistic pairs. The results show that the wavelet packet- : coherence method can qualitatively describe the nonlinear coupling strength between muscles, which provides a theoretical reference for further revealing the mechanism of human motion control and the rehabilitation evaluation of patients with motor dysfunction.