Determination of the motor unit behavior of lumbar erector spinae muscles through surface EMG decomposition technology in healthy female subjects

Introduction: The aims of this study were to determine the motor unit behavior of the erector spinae muscles and to assess whether differences exist between the dominant/non-dominant sides of the back muscles. Methods: Nine healthy women, aged 21.7 years (±0.7), performed a back extension test. Surface electromyographic decomposition data were collected from both sides of the erector spinae and decomposed into individual motor unit action potential trains. The mean firing rate for each motor unit was calculated, and a regression analysis was performed against the corresponding recruitment thresholds. Results: The mean firing rate ranged from 15.9 to 23.9 pulses per second (pps) and 15.8 to 20.6 pps on the dominant and non-dominant sides, respectively. However, the early motor unit potential s of the non-dominant lumbar erector spinae muscles were recruited at a lower firing rate. Conclusions: This technique may further our understanding of individuals with back pain and other underlying neuromuscular diseases

Evaluación isocinética de los músculos de la rodilla en jugadores de fútbol : análisis discriminante

Introdução: a atividade muscular em jogadores de futebol pode ser medida por meio do dinamômetro isocinético, que é um instrumento confiável para avaliação do desempenho humano. Objetivos: conduzir análises isocinéticas e discriminar quais variáveis diferenciam a categoria sub-17 (S17) da profissional (PRO).Métodos:Trinta e quatro jogadores de futebol (n=17 para cada categoria) foram avaliados. As variáveis isocinéticas utilizadas para a análise de extensão-flexão do joelho foram: pico de torque (Nm), trabalho total (J), potência média (W), ângulo de pico de torque (graus), razão agonista/antagonista (%), testadas em três velocidades (60°/s, 120°/s e 300°/s), com cada série contendo cinco repetições. Três análises discriminantes foram feitas usando o método Wilk's Lambda para identificar quais variáveis fariam uma discriminação significativa entre as duas categorias. Resultados: as variáveis discriminantes a 60°/s na categoria PRO foram: pico de torque extensores, trabalho total flexores, potência média de extensores e razão agonista/antagonista; e para os S17 foram: trabalho total de extensores, pico de torque de flexores e potência média de flexores. A 120°/s para a categoria PRO as variáveis discriminantes foram: pico de torque de flexores e potência média de extensores; para os S17 foram: trabalho total de extensores e potência média de flexores. A 300°/s, as variáveis encontradas para as categorias PRO e S17 foram, respectivamente: potência média de extensores e trabalho total de extensores. Conclusão: as variáveis isocinéticas para os músculos do joelho flexores e extensores foram capazes de fazer uma discriminação significativa entre jogadores de futebol PRO e S17.Introduction: muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance. Objectives: to perform isokinetic analyses and to determine which variables differentiate the under-17 (U17) soccer category from the professional (PRO). Methods: thirty four players were assessed (n=17 for each category). The isokinetic variables used for the knee extension-flexion analysis were: peak torque (Nm), total work (J), average power (W), angle of peak torque (deg.), agonist/ antagonist ratio (%), measured for three velocities (60°/s, 120°/s and 300°/s), with each series containing five repetitions. Three Wilks' Lambda discriminant analyses were performed, to identify which variables were more significant for the definition of each of the categories. Results: the discriminative variables at 60°/s in the PRO category were: extension peak torque, flexion total work, extension average power and agonist/antagonist ratio; and for the U17s were: extension total work, flexion peak torque and flexion average power. At 120°/s for the PRO category the discriminant variables were: flexion peak torque and extension average power; for the U17s they were: extension total work and flexion average power. Finally at 300°/s, the variables found in the PRO and U17 categories respectively were: extension average power and extension total work. Conclusion: isokinetic variables for flexion and extension knee muscles were able to significantly discriminate between PRO and U17 soccer players.Introducción: la actividad muscular en jugadores de fútbol puede ser medida por medio del dinamómetro isocinético, que es un instrumento confiable para evaluación del desempeño humano. Objetivos: conducir análisis isocinéticos y discriminar qué variables diferencian la categoría sub-17 (S17) de la profesional (PRO). Métodos: fueron evaluados treinta y cuatro jugadores de fútbol (n=17 para cada categoría). Las variables isocinéticas utilizadas para el análisis de extensión-flexión de la rodilla fueron: pico de torque (Nm), trabajo total (J), potencia media (W), ángulo de pico de torque (grados), razón agonista/antagonista (%), probadas en tres velocidades (60°/s, 120°/s y 300°/s), con cada serie conteniendo cinco repeticiones. Fueron realizados tres análisis discriminantes usando el método Wilk's Lambda para identificar qué variables harían una discriminación significativa entre las dos categorías. Resultados: las variables discriminantes a 60°/s en la categoría PRO fueron: pico de torque extensores, trabajo total flexores, potencia media de extensores y razón agonista/antagonista; y para los S17 fueron: trabajo total de extensores, pico de torque de flexores y potencia media de flexores. A 120°/s para la categoría PRO las variables discriminantes fueron: pico de torque de flexores y potencia media de extensores; para los S17 fueron: trabajo total de extensores y potencia media de flexores. A 300°/s, las variables encontradas para las categorías PRO y S17 fueron, respectivamente: potencia media de extensores y trabajo total de extensores. Conclusión: las variables isocinéticas para los músculos de la rodilla flexores y extensores fueron capaces de hacer una discriminación significativa entre jugadores de fútbol PRO y S17

Isokinetic evaluation of knee muscles in soccer players: discriminant analysis [Avaliação isocinética dos músculos do joelho em jogadores de futebol: análise discriminante]; [Evaluación isocinética de los músculos de la rodilla en jugadores de fútbol: análisis discriminante]

Introduction: Muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance. Objectives: To perform isokinetic analyses and to determine which variables differentiate the under-17 (U17) soccer category from the professional (PRO). Methods: Thirty four players were assessed (n=17 for each category). The isokinetic variables used for the knee extension-flexion analysis were: peak torque (Nm), total work (J), average power (W), angle of peak torque (deg.), agonist/ antagonist ratio (%), measured for three velocities (60°/s, 120°/s and 300°/s), with each series containing five repetitions. Three Wilks' Lambda discriminant analyses were performed, to identify which variables were more significant for the definition of each of the categories. Results: The discriminative variables at 60°/s in the PRO category were: extension peak torque, flexion total work, extension average power and agonist/antagonist ratio; and for the U17s were: extension total work, flexion peak torque and flexion average power. At 120°/s for the PRO category the discriminant variables were: flexion peak torque and extension average power; for the U17s they were: extension total work and flexion average power. Finally at 300°/s, the variables found in the PRO and U17 categories respectively were: extension average power and extension total work. Conclusion: Isokinetic variables for flexion and extension knee muscles were able to significantly discriminate between PRO and U17 soccer players. RESUMO Introdução: A atividade muscular em jogadores de futebol pode ser medida por meio do dinamômetro isocinético, que é um instrumento confiável para avaliação do desempenho humano. Objetivos: Conduzir análises isocinéticas e discriminar quais variáveis diferenciam a categoria sub-17 (S17) da profissional (PRO). Métodos: Trinta e quatro jogadores de futebol (n=17 para cada categoria) foram avaliados. As variáveis isocinéticas utilizadas para a análise de extensão-flexão do joelho foram: pico de torque (Nm), trabalho total (J), potência média (W), ângulo de pico de torque (graus), razão agonista/antagonista (%), testadas em três velocidades (60°/s, 120°/s e 300°/s), com cada série contendo cinco repetições. Três análises discriminantes foram feitas usando o método Wilk's Lambda para identificar quais variáveis fariam uma discriminação significativa entre as duas categorias. Resultados: As variáveis discriminantes a 60°/s na categoria PRO foram: pico de torque extensores, trabalho total flexores, potência média de extensores e razão agonista/antagonista; e para os S17 foram: trabalho total de extensores, pico de torque de flexores e potência média de flexores. A 120°/s para a categoria PRO as variáveis discriminantes foram: pico de torque de flexores e potência média de extensores; para os S17 foram: trabalho total de extensores e potência média de flexores. A 300°/s, as variáveis encontradas para as categorias PRO e S17 foram, respectivamente: potência média de extensores e trabalho total de extensores. Conclusão: As variáveis isocinéticas para os músculos do joelho flexores e extensores foram capazes de fazer uma discriminação significativa entre jogadores de futebol PRO e S17. RESUMEN Introducción: La actividad muscular en jugadores de fútbol puede ser medida por medio del dinamómetro isocinético, que es un instrumento confiable para evaluación del desempeño humano. Objetivos: Conducir análisis isocinéticos y discriminar qué variables diferencian la categoría sub-17 (S17) de la profesional (PRO). Métodos: Fueron evaluados treinta y cuatro jugadores de fútbol (n=17 para cada categoría). Las variables isocinéticas utilizadas para el análisis de extensión-flexión de la rodilla fueron: pico de torque (Nm), trabajo total (J), potencia media (W), ángulo de pico de torque (grados), razón agonista/antagonista (%), probadas en tres velocidades (60°/s, 120°/s y 300°/s), con cada serie conteniendo cinco repeticiones. Fueron realizados tres análisis discriminantes usando el método Wilk's Lambda para identificar qué variables harían una discriminación significativa entre las dos categorías. Resultados: Las variables discriminantes a 60°/s en la categoría PRO fueron: pico de torque extensores, trabajo total flexores, potencia media de extensores y razón agonista/antagonista; y para los S17 fueron: trabajo total de extensores, pico de torque de flexores y potencia media de flexores. A 120°/s para la categoría PRO las variables discriminantes fueron: pico de torque de flexores y potencia media de extensores; para los S17 fueron: trabajo total de extensores y potencia media de flexores. A 300°/s, las variables encontradas para las categorías PRO y S17 fueron, respectivamente: potencia media de extensores y trabajo total de extensores. Conclusión: Las variables isocinéticas para los músculos de la rodilla flexores y extensores fueron capaces de hacer una discriminación significativa entre jugadores de fútbol PRO y S17

Análise comparativa da atividade elétrica do músculo multífido durante exercícios do Pilates, série de Williams e Spine Stabilization

Introdução: A fraqueza da musculatura paraespinhal está relacionada à etiologia da dor lombar. Atualmente existem vários métodos que apresentam exercícios para o fortalecimento dessa musculatura. Objetivos: Comparare analisar o sinal eletromiográfico do músculo multífido bilateralmente durante exercícios do método Pilates, série de Williams e Spine Stabilization. Materiais e métodos: Participaram do estudo dez mulheres voluntárias e saudáveis que realizaram os exercícios leg pull front support modificado do Pilates, o quarto exercício da série adicional de Williams e o quadruped exercise do Spine Stabilization. O sinal foi normalizado pelo pico eletromiográfico da atividade dinâmica e foram ajustados para 2000 amostras por segundo e o filtro em uma frequência de passagem de 20 a 450 Hz. A ANOVA foi utilizada para verificar diferenças entre os exercícios, o teste t para amostras dependentes foi usado para comparar a ativação entre os lados direito e esquerdo do multífido para cada exercício. Resultados e considerações finais: Na comparação entre os exercícios, observaram-se diferenças significativas para o músculo multífido a favor do exercício do método Pilates tanto na fase concêntrica quanto na excêntrica, o que demonstra ser o exercício de melhor ativação elétrica para o músculo analisado

Análise comparativa da atividade elétrica do músculo multífido durante exercícios do Pilates, série de Williams e Spine Stabilization

INTRODUÇÃO: A fraqueza da musculatura paraespinhal está relacionada à etiologia da dor lombar. Atualmente existem vários métodos que apresentam exercícios para o fortalecimento dessa musculatura. OBJETIVOS: Comparar e analisar o sinal eletromiográfico do músculo multífido bilateralmente durante exercícios do método Pilates, série de Williams e Spine Stabilization. MATERIAIS E MÉTODOS: Participaram do estudo dez mulheres voluntárias e saudáveis que realizaram os exercícios leg pull front support modificado do Pilates, o quarto exercício da série adicional de Williams e o quadruped exercise do Spine Stabilization. O sinal foi normalizado pelo pico eletromiográfico da atividade dinâmica e foram ajustados para 2000 amostras por segundo e o filtro em uma frequência de passagem de 20 a 450 Hz. A ANOVA foi utilizada para verificar diferenças entre os exercícios, o teste t para amostras dependentes foi usado para comparar a ativação entre os lados direito e esquerdo do multífido para cada exercício. RESULTADOS E CONSIDERAÇÕES FINAIS: Na comparação entre os exercícios, observaram-se diferenças significativas para o músculo multífido a favor do exercício do método Pilates tanto na fase concêntrica quanto na excêntrica, o que demonstra ser o exercício de melhor ativação elétrica para o músculo analisado

Effect of an exercise program on risk factors of falls in elderly women = Efeito de um programa de exercícios físicos nos fatores de risco de quedas em idosas

The aim of this study was to verify the benefits of an exercise program on functional capacity and balance in elderly community. A longitudinal study was conducted with 11 female subjects with mean age 77 (SD = 13) years. All individuals were evaluated at the beginning and at the end of the study by ‘Berg’ Balance Scale and ‘Timed Up and Go’ Test. Initially, the participants answered a questionnaire about the socio-demographics aspects, health conditions, falls and physical activity practice. Then, the subjects were submitted to a program of exercises for balance, strengthening and stretching muscles. The results of the ‘Berg’ Scale ranged from 46 to 56 points before the intervention, and from 50 to 56, after the intervention (p = 0.01). Individuals older than 75 years old had a better improvement (p = 0.04). In the ‘Timed Up and Go’ Test the percentage of improvement was 8.2% ( = 13.1; SD= 11.7). The exercise program showed a positive effect in improving risk factors of falls in the elderly community.<br><br>Objetivo deste estudo foi verificar os benefícios de um programa de exercícios físicos na capacidade funcional e equilíbrio de idosos. Foi realizado um estudo longitudinal com a participação de 11 indivíduos do gênero feminino, com idade média de 77 anos (DP = 13). Todos foram avaliados no início e final do estudo pela Escala de Equilíbrio de Berg e pelo teste Timed Up and Go. Inicialmente, as participantes responderam um questionário por meio de entrevista, que abordava aspectos sociodemográficos, condições de saúde, quedas e prática de atividade física. Na sequência, as idosas foram submetidas a um programa de exercícios de treino de equilíbrio, fortalecimento e alongamentos musculares. Os resultados da escala de Berg variaram de 46 a 56 pontos, antes da intervenção e de 50 a 56 após a intervenção (p = 0,01). Os sujeitos com mais de 75 anos tiveram melhora superior (p = 0,04). No teste Timed Up and Go o percentual de melhora foi de 8,2% ( = 13,1; DP = 11,7). O programa de exercícios desenvolvido apresentou efeito positivo na melhora dos fatores de risco de quedas em idosos

Intervening factors in the walking of children presenting myelomeningocele

Introduction: All children presenting myelomeningocele are capable of walking. Certain interventionscan influence the walking prognosis of these children: physical therapy, medication, and nutritional orientation.Objectives: The aim of this study was to verify the association between ability to walk in childrenwith myelomeningocele and clinical, socioeconomic and therapeutic factors. Method: This cross-sectionalstudy was conducted at the University Hospital. The participants were children aged two years-old ormore, diagnosed with myelomeningocele. Data collection was conducted by physical therapy assessmentand medical records. The dependent variable was walking and the independent variables were clinical,socioeconomic and therapeutic factors. Results: Forty-one children were evaluated, with a median age of5 years-old (2-9). The clinical factors that revealed an association with walking were neurological area (p elt; 0,0001) and fractures (p = 0,022). Socioeconomic factors showed not to be significant in relation to ability towalk. Surgery (p = 0,017) and the use of assistive devices (p = 0,023) were also associated with the ability towalk. Conclusion: The determinant clinical factor for walking prognosis was the neurological area. The useof assistive devices and surgical intervention were shown to be necessary for promoting walking activity

Assessment of measurement properties of the Brazilian-Portuguese version of the low back activity confidence scale (LoBACS) in patients with chronic low back pain.

The Low Back Activity Confidence Scale (LoBACS) assesses the self-efficacy to perform activities in individuals with chronic low back pain (CLBP). As self-efficacy appears to directly influence the patient's functional capacity and prognosis, it is important to develop a scale that evaluates this attribute to guide treatment strategy and monitor the clinical course of patients. This study aimed to evaluate the reliability, construct validity, and responsiveness of the Brazilian version of the LoBACS. The scale was applied to 112 male and female patients (age, 18-65 years) with specific and nonspecific CLBP. For evaluating the interobserver reliability, the scale was applied twice on the first evaluation day by two trained evaluators (A and B). Within 48-72 h of the first evaluation, assessor A reapplied the scale to evaluate intraobserver reliability (test-retest), which was analyzed by intraclass correlation coefficient (ICC). The first LoBACS applied in the baseline evaluation was also used to assess the construct validity of the scale by factor analysis. For responsiveness, the scale was applied 5 times at 2-week intervals and the change in scores was analyzed by the repeated measures ANOVA. Although factor analysis indicated three subscales, they did not present acceptable values of convergent and divergent validity. Reliability ranged from good to excellent, with ICC values of .90 (95% CI, .84; .93) and .85 (95% CI, .77; .91) for inter- and intraobserver variability for total score. Moreover, the total score was responsive in all comparisons, with no floor or ceiling effects. Thus, only the total score of the Brazilian version of LoBACS proved to be reliable, valid, and responsive

Intervening factors in the walking of children presenting myelomeningocele

INTRODUCTION: All children presenting myelomeningocele are capable of walking. Certain interventions can influence the walking prognosis of these children: physical therapy, medication, and nutritional orientation. OBJECTIVES: The aim of this study was to verify the association between ability to walk in children with myelomeningocele and clinical, socioeconomic and therapeutic factors. METHOD: This cross-sectional study was conducted at the University Hospital. The participants were children aged two years-old or more, diagnosed with myelomeningocele. Data collection was conducted by physical therapy assessment and medical records. The dependent variable was walking and the independent variables were clinical, socioeconomic and therapeutic factors. RESULTS: Forty-one children were evaluated, with a median age of 5 years-old (2-9). The clinical factors that revealed an association with walking were neurological area (p < 0,0001) and fractures (p = 0,022). Socioeconomic factors showed not to be significant in relation to ability to walk. Surgery (p = 0,017) and the use of assistive devices (p = 0,023) were also associated with the ability to walk. Conclusion: The determinant clinical factor for walking prognosis was the neurological area. The use of assistive devices and surgical intervention were shown to be necessary for promoting walking activity

Kinematic gait analysis using inertial sensors with subjects after stroke in two different arteries

[Purpose] The aim of the present study was described the kinematic characteristics of gait in stroke patients with two different arteries involved. [Subjects and Methods] Two patients who had suffered a basilar (A) or middle (B) cerebral artery ischemic stroke were compared with a control (C). Seventeen inertial sensors were used with acquisition rate of 120 Hz. The participants walked 3 times on a 10 meter walkway. From the raw data, the three gait cycles from the middle of each trial were chosen and analyzed. [Results] During the stance phase, patients A and B had a lower hip angle at initial contact and maximum flexion angle during load response than the control. Patient A and the control subject had similar knee angle values at initial contact, and patient B presented a flexed position in the initial phase of the gait cycle. The maximum flexion angles during loading response were also higher for patient B. The sagittal plane excursion for the ankle joint was lower for patient B in comparison with the other subjects. [Conclusion] Differences during walking between patients who had stroke in different arteries may be related to an alternative compensatory strategy. Patient A and the control subject had similar gait cycle curves at all joints, while patient B showed a rigid synergic pattern