Influence of probe position in the measurement of muscle thickness and its association with lean mass: an ultrasound study / Influencia de la posición de la sonda en la medición del grosor muscular y su asociación con la masa magra: un estudio ecográfico

SUMMARY: Skeletal muscles play a fundamental role in people's lives and their evaluation provides significant information on health. Different tools have been used to evaluate muscle mass, and the evaluation of muscle thickness (MT) using ultrasound has been included as an alternative, which can be performed with the probe in different positions; however, these could present differences. The objectives of this study were to determine whether there are differences in the measurement of MT in the vastus lateralis (VL) muscle using the probe in the longitudinal or transverse position, and to determine its association with the lean mass of the lower limbs. The results indicated no significant differences between MT measurements with the probe in the longitudinal and transverse positions (p =0.084). However, when associating these measurements with lower limb lean mass, it was found that transverse measurements had a strong association (r =0.547; p < 0.001), while longitudinal measurements had a moderate association (r =0.351; p =0.007). This suggests that measurements with the probe positioned transversely to measure the MT would be the best option. Therefore, it could be useful as an indicator of lower limb lean mass in the absence of tools, such as bioelectrical bioimpedance or magnetic nuclear resonance.

El músculo esquelético cumple un rol fundamental en la vida de las personas, y su evaluación entrega mucha información de la salud. Se han utilizado diferentes herramientas para evaluar la masa muscular, y el último tiempo se ha incluido la evaluación del grosor muscular (MT) a través de la ecografía como una alternativa para estimarla, las cuales se pueden realizar con la sonda en distintas posiciones, sin embargo, estas podrían presentar diferencias. Los objetivos del estudio fueron determinar si existen diferencias en la medición de MT en el músculo vasto lateral (VL) utilizando la sonda en posición longitudinal o transversal y determinar su asociación con la masa magra de los miembros inferiores. Los resultados indican que no existen diferencias significativas entre las mediciones de MT con la sonda en posición longitudinal y transversal (valor p: 0.084). Sin embargo, al asociar estas mediciones con la masa magra de los miembros inferiores, se encontró que las mediciones transversales poseen una asociación fuerte (r: 0.547; valor p < 0.001), mientras que las mediciones longitudinales presentan una asociación moderada (r: 0.351; valor p: 0.007). Esto sugiere que las mediciones con la sonda posicionada transversal para medir MT serían la mejor opción. Por lo tanto, podría ser de utilidad como un indicador de masa magra de los miembros inferiores en caso de no contar con herramientas como la bioimpedancia bioeléctrica o resonancia nuclear magnética.

Localización biométrica de los puntos motores del músculo cuádriceps femoral de individuos brasileños / Biometric localization of the motor points of the femoral quadriceps muscle of Brazilian individuals

El músculo cuadríceps femoral es un músculo que participa principalmente en los movimientos de la rodilla y también en la cadera, pudiendo ser afectado por alteraciones en el trofismo muscular, tras lesiones de estas articulaciones o afecciones en el tono muscular, como la espasticidad, tras lesiones cerebrovasculares. Cada una de sus cabezas está inervada por ramos del nervio femoral. El presente estudio tuvo por objetivo la identificación y medición de la distancia de los puntos motores (Pm) del músculo cuadríceps femoral, en relación a estructuras anatómicas de relevancia clínica. Se utilizaron 30 miembros inferiores de 23 cadáveres formolizados, de individuos brasileños adultos. El estudio fue realizado en la Universidade Estadual de Ciências da Saúde de Alagoas (UNCISAL), Maceió, Brasil. Se realizó la disección por planos en la zona medial, anterior y lateral del muslo, identificando a los ramos del nervio femoral para cada componente, músculos recto femoral (mRf), vasto medial (mVm), vasto intermedio (mVint) y vasto lateral (mVlat), localizando cada uno de los Pm. Las mediciones se realizaron con un cáliper marca Mitutoyo de 0,05 mm de precisión. Los datos obtenidos fueron tratados estadísticamente, utilizando para ello, el software STATA (versión 14.1). El mRf, tuvo un promedio de 2,45 ± 1,39 Pm, estando la gran mayoría de los Pm (63 %), en la zona distal del tercio proximal del muslo; el mVm presentó 4,42 ± 2,74 Pm en promedio, encontrándose el 41 % de ellos en el tercio medio del muslo, zona distal; el mVint tuvo 3,99 ± 2,34 Pm en promedio y el 58 % de ellos, se localizaron en la zona proximal del tercio medio del muslo; el mVlat presentó un promedio de 3,88 ± 2,37 Pm y el 50 % de éstos se encontraron en del tercio proximal del muslo. La localización biométrica de los Pm se informa en resultados. La ubicación biométrica de los Pm, favorecerá el quehacer, tanto clínico como quirúrgico, de la zona anterior del muslo.

The quadriceps femoris muscle is a muscle that participates mainly in the movements of the knee and also in the hip, being able to be affected by alterations in muscle trophism, after injuries of these joints or muscular tone conditions, such as spasticity, after injuries cerebrovascular. Each of its heads is innervated by branches of the femoral nerve. The objective of this study was to identify and measure the distance of the motor points (MP) of the quadriceps femoris muscle, in relation to anatomical structures of clinical relevance. Thirty lower limbs of 23 formolized corpses of adult Brazilian individuals were used. The study was conducted at the State University of Ciências da Saúde de Alagoas (UNCISAL), Maceió, Brazil. The dissection was performed by planes in the medial, anterior and lateral thigh, identifying the femoral nerve branches for each component, rectus femoris muscles (Rfm), medial vastus (mVm), vastus intermedius (intVm) and vastus lateralis ( latVm), locating each of the MP. The measurements were made with a Mitutoyo caliper of 0.05 mm accuracy. The data obtained were treated statistically, using the STATA software (version 14.1). The Rfm had an average of 2.45 ± 1.39 MP, the great majority of the MP (63 %) being in the distal area of the proximal third of the thigh; the mVm presented 4.42 ± 2.74 MP on average, with 41 % of them in the middle third of the thigh, distal zone; the intVm had 3.99 + 2.34 MP on average and 58 % of them were located in the proximal area of the middle third of the thigh; the latVm presented an average of 3.88 ± 2.37 MP and 50 % of these were found in the proximal third of the thigh. The biometric localization of the MP is reported in results. The biometric location of the MP, will favor the task, both clinical and surgical of the anterior thigh area.

Efeitos do exercício passivo precoce em cicloergômetro na espessura muscular do quadríceps femoral de pacientes críticos: estudo-piloto randomizado controlado / Efectos del ejercicio pasivo precoz en cicloergómetro en el espesor muscular del cuádriceps femoral de pacientes críticos: un estudio piloto aleatorizado controlado / Effects of early passive cycling exercise on quadriceps femoris thickness in critically ill patients: a controlled randomized pilot study

RESUMO O objetivo deste estudo foi avaliar os efeitos do exercício passivo precoce em cicloergômetro na espessura muscular (EM) do quadríceps femoral (EMQ) de pacientes críticos admitidos em uma Unidade de Terapia Intensiva (UTI) de um hospital universitário terciário. O método utilizado foi um estudo-piloto randomizado controlado conduzido em uma amostra de 24 pacientes (51±18,11 anos, 16 do sexo masculino), com 24 a 48 horas de ventilação mecânica (VM), aleatoriamente divididos em dois grupos: grupo-controle (n=12), que recebeu a fisioterapia convencional; e grupo-intervenção (n=12), que recebeu o exercício passivo em cicloergômetro, uma vez ao dia, durante o período de sete dias do protocolo, em adição à fisioterapia convencional. A EMQ foi mensurada através da ultrassonografia. A primeira medida ultrassonográfica foi realizada entre as primeiras 48 horas de VM e a segunda ao término do protocolo. Não houve diferenças significativas na EMQ esquerda (27,29±5,86mm vs. 25,95±10,89mm; p=0,558) e direita (24,96±5,59mm vs 25,9±9,21mm; p=0,682) do grupo-controle e na EMQ esquerda (27,2±7,38mm vs 29,57±7,89mm; p=0,299) e direita (26,67±8,16mm vs 28,65±8,04mm; p=0,381) do grupo-intervenção. Na comparação entre os grupos, não houve alterações significativas em relação à EMQ esquerda (3,61±1,07mm; p=0,248) e a EMQ direita (2,75±0,85mm; p=0,738). Os resultados deste estudo-piloto demonstraram que a aplicação precoce do exercício passivo em cicloergômetro não promoveu mudanças significativas na espessura da camada muscular avaliada. No entanto, nossos achados sinalizam que a fisioterapia convencional foi capaz de preservar a EMQ de pacientes críticos admitidos em UTI.

RESUMEN El presente estudio tuvo como objetivo evaluar los efectos del ejercicio pasivo precoz en cicloergómetro en el espesor muscular (EM) del cuádriceps femoral (EMC) de pacientes críticos ingresados en una Unidad de Cuidados Intensivos (UCI) de un hospital universitario terciario. Se utilizó como método un estudio piloto aleatorizado controlado con una muestra de 24 pacientes (51±18,11 años, 16 varones), con 24 a 48 horas de ventilación mecánica (VM), quienes fueron divididos aleatoriamente en dos grupos: grupo de control (n=12), que recibió fisioterapia convencional; y grupo intervención (n=12), que recibió el ejercicio pasivo en cicloergómetro una vez al día durante el período de protocolo de siete días, además de la fisioterapia convencional. El EMC se midió por ecografía. La primera medición ecográfica se realizó entre las primeras 48 horas de VM, y la segunda al final del protocolo. No hubo diferencias significativas en el EMC izquierdo (27,29±5,86 mm vs. 25,95±10,89mm; p=0,558) y derecho (24,96±5,59mm vs 25,9±9,21mm; p=0,682) del grupo de control; y en el EMC izquierdo (27,2±7,38mm vs 29,57±7,89mm; p=0,299) y derecho (26,67±8,16mm vs 28,65±8,04mm; p=0,381) del grupo intervención. En la comparación entre grupos, no hubo cambios significativos en el EMC izquierdo (3,61±1,07 mm; p=0,248) y en el EMC derecho (2,75±0,85 mm, p=0,738). Los resultados de este estudio piloto demostraron que la aplicación precoz del ejercicio pasivo en cicloergómetro no promovió cambios significativos en el espesor de la capa muscular evaluada. Sin embargo, nuestros hallazgos indican que la fisioterapia convencional pudo preservar el EMC de pacientes críticos ingresados en la UCI.

ABSTRACT The objective of this study was to evaluate the effects of early passive cycling exercise on quadriceps femoris thickness (QFT) in critically ill patients admitted in the intensive care unit (ICU) of a tertiary care university hospital. A controlled randomized pilot study was conducted with a sample of 24 patients (51±18.11 years, 16 male), on mechanical ventilation (MV) from 24 to 48 hours, who were randomly divided into two groups: control group (n=12), receiving conventional physical therapy; and an intervention one (n=12), receiving passive cycle ergometer, once a day, throughout seven days of protocol, in addition to conventional physical therapy. The QFT was measured by ultrasonography. The first ultrasonographic measurement was performed within 48 hours after the start of MV, and the second at the end of the protocol. There were no significant differences in QFT of the left (27,29±5,86mm vs 25,95±10,89mm; p=0,558) and right (24,96±5,59mm vs 25,9±9,21mm; p=0,682) in the control group, and in QFT of the left (27,2±7,38mm vs 29,57±7,89mm; p=0,299) and right (26,67±8,16mm vs 28,65±8,04mm; p=0,381) in the intervention group. There were no significant between-groups differences for left QFT (3,61±1,07mm; p=0,248) and right QFT (2,75±0,85mm; p=0,738). The results of this pilot study demonstrate that application of early passive cycle ergometer exercises has not significantly change the muscle layer thickness. However, our findings indicate that conventional physical therapy is able to preserve the quadriceps femoris thickness in critically ill patients admitted in ICU.

Morphological analysis of articularis genus and involvement in muscle synchronicity with vastus intermedius / Análisis morfológico del músculo articular de la rodilla y su participación en la sincronicidad muscular con el músculo vasto intermedio

The articularis genus, which lies under the vastus intermedius, has been regarded as part of the quadriceps femoris. However, they are well known to have different function because their respective origins and insertions are mutually distinct. These muscles are considered to work almost simultaneously when the knee is extended. The electromyogram has been used to demonstrate muscle co-contraction. However, the articularis genus is deeper than other muscles. Moreover, it is difficult to analyze it by surface electromyogram. The relative proportions of muscle fiber types and the characteristics of these fiber types are important determinants of the surface electromyogram. Furthermore, biomechanical analysis of AG has remained unclear. This study investigated the ratio of muscle fiber types in these muscles. Muscle samples from seven human cadaveric specimens were used with application of immunofluorescence double staining. Results show that in the vastus intermedius and articularis genus, the percentage of Type I fibers was significantly higher than that of Type II fibers. No significant difference was found in the mean percentages of Type I and Type II fiber types. The percentages of Type I and Type II fibers in articularis genus muscle were correlated positively to the percentage in the vastus intermedius. These results suggest that similar muscle fiber compositions of these muscles might reflect their contraction during the same active phase of knee extension, despite their different functions.

El músculo articular de la rodilla, que se encuentra cubierto por el músculo vasto intermedio, se ha considerado como parte del músculo cuádriceps femoral. Sin embargo, es sabido que tienen diferentes funciones debido a que sus respectivos orígenes e inserciones son mutuamente distintas. Se considera que estos músculos trabajan de forma casi simultánea cuando la rodilla está extendida. El electromiograma se ha usado para demostrar la contracción muscular. Sin embargo, el músculo articular de la rodillas es más profundo que otros músculos. Además, es difícil analizarlo por electromiograma de superficie. Las proporciones relativas de los tipos de fibras musculares y las características de estos tipos de fibras son importantes determinantes del electromiograma de superficie. Además, el análisis biomecánico de músculo articular de la rodilla no ha sido claro. Este estudio investigó la proporción de tipos de fibras musculares en estos músculos. Se usaron muestras musculares de siete cadáveres humanos con la aplicación de doble tinción de inmunofluorescencia. Los resultados muestran que en los músculos articular de la rodilla y vasto intermedio, el porcentaje de fibras de Tipo I fue significativamente mayor que el de las fibras de Tipo II. No se encontraron diferencias significativas en los porcentajes medios de los Tipo I y Tipo II. Los porcentajes de fibras Tipo I y Tipo II en el músculo articular de la rodilla se correlacionaron positivamente con el porcentaje en el músculo vasto intermediario. Estos resultados sugieren que las composiciones de las fibras musculares similares de estos músculos podrían reflejar su contracción durante la misma fase activa de la extensión de la rodilla, a pesar de sus diferentes funciones.

Anatomical attributes of the musculus quadriceps femoris responsible for poor crawling ability in the greater horseshoe bat ( Rhinolophus ferrumequinum ) / Atributos anatómicos del músculo cuádriceps femoral responsable de la limitada capacidad de arrastre en el murciélago grande de herradura ( Rhinolophus ferrumequinum )

SUMMARY: In mammals, the Musculus quadriceps femoris is a well-developed extensor muscle of the thigh. It is also relatively well developed in bats. The muscle group consists of a distally elongated muscle belly, which is important for the full extension of the knee joint during terrestrial locomotion. However, most bats species demonstrate poor terrestrial locomotion, although several species are able to crawl on the ground. Among the crawling bats, knee joint extension is necessary for crawling. Among bat species generally, the M. quadriceps femoris has a distally elongated belly for extending the shank, although the feature also occurs among poor crawling bat species. The relationship between a relatively well-developed M. quadriceps femoris and poor crawling ability in bats is incongruous, but there is a possibility that bats with a reduced M. quadriceps femoris have not yet been found. The greater horseshoe bat (Rhinolophus ferrumequinum) has long been known to be incapable of crawling, but there are no detailed descriptions in the literature concerning this bat's M. quadriceps femoris. The findings of this study reveal that the M. quadriceps femoris of Rh. ferrumequinum has a short muscle belly attached to the proximal portion of the femur; furthermore, the insertional tendon of this muscle and its patellar ligament are very thin. These morphological features suggest that this species cannot exert a strong and long-distance extension of its knee joints, unlike most other bat species. In addition to the above described morphological features, the M. rectus femoris of Rh. ferrumequinum is fused with the vasti in the M. quadriceps femoris. This M. quadriceps femoris arises from the pelvis and inserts onto the femur. Therefore, Rh. ferrumequinum has an M. quadriceps femoris specialized for flexion of the hip joint.

RESUMEN: En los mamíferos, el Musculus quadriceps femoris es un músculo extensor bien desarrollado del muslo. Este músculo también está relativamente bien desarrollado en murciélagos. El grupo muscular consiste en un vientre muscular distalmente alargado, lo que es importante para la extensión completa de la articulación de la rodilla durante la locomoción terrestre. Sin embargo, la mayoría de las especies de murciélagos muestran limitada locomoción terrestre, aunque varias especies pueden arrastrarse por el suelo. Entre los murciélagos reptantes, la extensión de la articulación de la rodilla es necesaria para gatear. Entre las especies de murciélagos en general, el M. quadriceps femoris tiene un vientre distalmente alargado para extender la rodilla, aunque la característica también ocurre entre las especies de murciélagos de rastreo limitado. La relación entre un M. quadriceps femoris relativamente bien desarrollado y la escasa capacidad de rastreo en los murciélagos es incongruente, pero existe la posibilidad de que aún no se hayan encontrado murciélagos con M. cuádriceps femoral poco desarrollado. Se sabe desde hace tiempo que el murciélago de herradura (Rhinolophus ferrumequinum) es incapaz de gatear, pero no hay descripciones detalladas en la literatura sobre el M. quadriceps femoris de este murciélago. Los hallazgos de este estudio revelan que el M. quadriceps femoris de Rh. ferrumequinum tiene un vientre muscular corto, unido a la epífisis proximal del fémur; además, el tendón de inserción de este músculo y su ligamento patelar son muy delgados. Estas características morfológicas sugieren que esta especie no puede ejercer una extensión importante y de larga distancia de la articulación de la rodilla, a diferencia de la mayoría de otras especies de murciélagos. Además de las características morfológicas descritas anteriormente, el M. rectus femoris de Rh. ferrumequinum está fusionadocon el vasto del M. quadriceps femoris. El M. quadriceps femoris se origina de la pelvis y se inserta en el fémur. Por lo tanto, Rh. ferrumequinum tiene un M. quadriceps femoris especializado para la flexión de la articulación de la cadera.

Desgarros del músculo recto femoral: Actualización en RM / Muscle injuries of the rectus femoris muscle. MR Update

El desgarro del músculo recto femoral (RF) es el más frecuente dentro del grupo muscular cuadricipital y representa una de las causas más habituales de lesiones musculares del miembro inferior (luego de la injuria del grupo isquiotibial). Dada la complejidad de su anatomía, la sintomatología puede ser poco clara, por lo que los métodos de diagnóstico por imagen y, en especial, la resonancia magnética (RM) aportan información precisa sobre el tipo de desgarro, topografía, extensión y severidad. En el presente artículo, se describe detalladamente la anatomía del RFy su estudio selectivo mediante RM, con aportes técnicos específicos para optimizar este método de estudio. Además, se desarrollan los conceptos actuales del desgarro tendinoso, miotendinoso y el infrecuente desgarro miofascial, aportando datos clave que deben estar contemplados en el informe de RM y que son de suma importancia para el médico traumatólogo.

The tear of the anterior rectus femoris is the most frequent injury of the quadriceps muscle group, and one of the most common causes of lower limb muscle lesions (after the injury of the hamstring muscle group). As its anatomy is complex, and symptoms may be unclear, imaging and in particular, Magnetic Resonance Imaging (MRI) provides precise information on the type of tear, topography, extent, and severity. This article presents a detailed description of the anatomy of the RF and a selective study by MRI, with specific technical inputs to optimise this study method. The current concepts of tendinous, myotendinous, and the infrequent myofascial muscle-tendon tears are also presented, with details of key information that must be contemplated in MRI reports of paramount importance to the traumatology doctor.

Anatomic study of the portions long and oblique of the vastus lateralis and vastus muscles: review article

Although not mentioned directly in the classical anatomical literature, the vastus lateralis and vastus medialis, which make up the quadriceps femoris muscle, show variations in their anatomical structures due to the presence of long and oblique portions receiving the designation of vastus lateralis longus, vastus lateralis obliques to the vastus lateralis and vastus medialis oblique and vastus long, for the vastus medialis. The aim of this paper is to review the scientific literature regarding the presence of long and oblique portions of the broad medial and lateral portions recognize these as integral parts, anatomically, the quadriceps femoris. To this end, we used published articles in magazines and journals, located through Medline, and Lilacs Excerpa Medica, and the Portal Capes, with the key words: quadriceps, vastus medialis, vastus lateralis, vastus medialis longus, vastus medialis oblique , vastus lateralis longus and vastus lateralis oblique. Used to, still, a master’s thesis, located at Portal Capes, plus textbooks and atlases of anatomy. Among the 27 surveyed, only two do not recognize these portions as independent structures, considering the differences in fiber orientation. Of the 18 studied anatomy books, no mention such parts. However, eight anatomy books describe differences in trajectory of fiber insertions of the vastus lateralis and vastus medialis. Before this study it was concluded that these portions have not only morphological differences but also in other respects proved through scientific studies being published in some of them considered independent muscle suggesting inclusion of muscles in Anatomical Nomina.

Functional and morphological changes in the quadriceps muscle induced by eccentric training after ACL reconstruction / Alterações funcionais e morfológicas do quadríceps induzidas pelo treinamento excêntrico após reconstrução do LCA

OBJECTIVES: The purpose of this study was to investigate the contributions of functional and morphological factors in the recovery of the quadriceps muscle after anterior cruciate ligament (ACL) reconstruction. METHODS: Nine subjects (31.3±5.8 years) underwent eccentric exercise sessions twice a week for 12 weeks. Quadriceps muscle function was evaluated using an isokinetic dynamometer (isometric and eccentric peak torque) and electromyography (RMS). Morphological changes were measured using magnetic resonance imaging. RESULTS: The initial evaluation showed a significant deficit in knee extensor torque in the involved limb and significant muscle atrophy along the length of the quadriceps. EMG activity was lower in all tested situations. Eccentric training significantly increased isokinetic torque (from 199±51 to 240±63, p<0.05, respectively) and quadriceps area, with the greatest hypertrophy in the proximal thigh region (from 169±27 to 189±25.8 cm², p<0.01). The EMG activity of vastus medialis increased after the first six weeks of eccentric training. The increased extensor torque was correlated with quadriceps cross-sectional area (r=0.81, p<0.01) and EMG activity (r=0.69, p<0.05). After twelve weeks of training, there was a correlation only between torque and cross-sectional area (r=0.78, p<0.01). CONCLUSIONS: 1) eccentric training proved to be a potent resource for the quadriceps recovery, both morphologically and functionally, 2) the contributions of functional and morphological factors varied according to the length of training.

OBJETIVOS: O propósito deste estudo foi avaliar as contribuições dos fatores funcionais e morfológicos na recuperação da força muscular do quadríceps femoral após reconstrução do Ligamento Cruzado Anterior (LCA). MÉTODOS: Nove indivíduos (31,3±5,8 anos) foram treinados por meio de contrações excêntricas máximas, duas vezes por semana, durante 12 semanas. A função do quadríceps foi avaliada pela dinamometria isocinética (pico de torque isométrico e excêntrico) e pela eletromiografia (EMG). As alterações morfológicas foram mensuradas por meio de ressonância magnética (RNM). Na avaliação inicial, observou-se significativo déficit no torque extensor do joelho do membro acometido, com hipotrofia muscular de todo o quadríceps e redução na atividade EMG, quando comparado ao membro não-acometido. RESULTADOS: O treinamento excêntrico produziu aumento no torque excêntrico a 30º/s (de 199±51 Nm para 240±63 Nm, p<0,05) e no volume muscular, sendo que maiores hipertrofias ocorreram na região proximal da coxa (de 169±27 para 189±25,8 cm², p<0,01). A atividade EMG do Vasto Medial (VM) aumentou nas primeiras seis semanas de treinamento. O aumento no torque extensor demonstrou correlação positiva com o aumento no volume (r=0,81, p<0,01) e na atividade eletromiográfica (EMG) (r=0,69, p<0,05) nas primeiras seis semanas. Após 12 semanas de treinamento, houve correlação apenas entre o aumento do torque e do volume (r=0,78, p<0,01). CONCLUSÕES: 1) O treinamento excêntrico mostrou-se como potente recurso tanto na recuperação dos fatores morfológicos como funcionais do músculo quadríceps; 2) A contribuição dos fatores neurais e morfológicos varia em função do período de treinamento.

Quantitative EMG Changes During 12-Week DeLorme's Axiom Strength Training

Strength training is one of the most common exercises practiced in the field of physical therapy or sports training. However, limited methodology is available to evaluate its effect on the target muscle. This study aimed to test the hypothesis that surface electromyographic (EMG) data from both isometric and isotonic exercise can express changes within the muscle during a 12-week strength training program. Ten healthy male volunteer students (5 for training, 5 for controls) from Yonsei University were recruited for evaluation in this study. DeLorme's axiom was practiced for 12 weeks in the dominant elbow flexors and knee extensors of the training group. Tension for 1 repetition maximum and maximal voluntary isometric contraction, and surface EMG information such as the integrated EMG and three variables from the regression line of median frequency (MDF) data were measured at weeks 0, 3, 6, 9, and 12. The limb circumference was measured at weeks 0 and 12. During the strength training, which was enough for the increment of muscle strength and limb circumference, the rectified-integrated EMG and initial MDF increased with a significant linear pattern in both types of contraction. The two surface EMG variables were able to monitor the physiologic muscle changes during the training. Based on these results, we propose that these two surface EMG variables can be used for monitoring electrophysiological changes in the specific muscle that is undergoing the training program, under conditions where the contraction mode for EMG data collection is either static or dynamic.

O mito da ativação seletiva do músculo vasto medial / The myth of the selective activation of the vastus medialis

Por ativação seletiva do vasto medial entende-se uma maior solicitação do vasto medial em relação ao vasto lateral durante a execução de um dado exercício. Diversas técnicas têm sido utilizadas ao longo dos anos na tentativa de alcançar uma diminuição na diferença de força entre esses dois componentes do quadríceps. Neste estudo foram revisados 26 trabalhos publicados entre os anos de 1955 e 2001, em que foram abordadas duas teorias principais de ativação seletiva do vasto medial: a ativação durante os últimos graus de extensão do joelho e a ativação seletiva através da combinação de movimentos. Após esta revisão bibliográfica, conclui-se que a evidência científicadisponível não apóia a hipótese ativação seletiva do vasto medial ao final da extensão. Com relação à utilização da combinação de exercícios, observa-se uma falta de consenso entre os autores, com a grande diversidade de metodologias dificultando uma conclusão definitiva.

As selective activation of the vastus medialis is understood a larger request of the vastus medialis in respect to the lateralis during the execution of an exercise. Several techniques have been used along the years in the attempt of reaching a decrease in the difference of force among those two components of the quadriceps. In this study were revised 26 papers published between 1955 and 2001 that approached two main theories of selective activation of the vastus medialis: the activation during the last degrees of extension of the knee and the selective activation through the combination of movements. After this bibliographical revision, it is concluded that the available scientific evidence do not support the notion of selective activation of the vastus medialis at the end of the extension. Regarding the use of the combination of exercises, a great consensus lack exists among the authors, with the great diversity of methodologies hindering a definitive conclusion.

Contribution to the anatomical study of the oblique portionof the Vasculite Laterais muscle

Thirty-two human thighs were dissected to determine the anatomical organization of the two portions of the vastuslateralis muscle, and their relationships with associated structures the lateral retinaculum and iliotibial tract. In all ofthe cases, the vastus lateralis muscle consisted of a long, proximal portion, (the vastus lateralis longus - VLL), and anoblique, distal portion (the vastus lateralis obliquus - VLO). The oblique portion (VLO) originated from the asperaline of the femur and from the lateral intermuscular septum. The tendon of the VLO ran below and laterally to the longportion (VLL), which it subsequently joined on the superolateral border of the patella. The VLO also interdigitatedwith the lateral retinaculum and iliotibial tract. The VLL showed an extensive aponeurosis in its proximal two thirds.The gross morphology of the VL muscle agreed whith previous descriptions for this muscle and suggested that theVLO could play an important role in patella stabilization. This muscle could therefore be of clinical importance in thetreatment of disorders involving the patellofemoral joint.Key words: Anatomy, lower limb, muscle, quadriceps femoris