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INTRODUCTION: The quadriceps femoris muscle is present in the anterior region of the thigh and is classically described as a muscle with four heads: rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. A few years ago, a "fifth head" was described and named the tensor of the vastus intermedius (TVI). The TVI belly is in line with the belly of the vastus lateralis, and its aponeurosis imposes considerable tension on the vastus intermedius, medializing its action, to play a significant role in knee extension. OBJECTIVE: To perform a study of the TVI incidence in a Brazilian population and describe its variations. MATERIAL AND METHODS: We dissected lower limbs from cadavers previously fixed in 10% formaldehyde, belonging to the Laboratory of Anatomy of the Department of Morphology of the Biosciences Center of the Federal University of Rio Grande do Norte. RESULTS: Eighty-one lower limbs were analyzed with only 33 (40.74%) of them presenting TVI. All four types of TVI described by the literature were present in our sample with the following distribution: type 1 with 15.15%; type 2 with 9.1%; type 3 with 33.33%; type 4 with 42.42%. DISCUSSION: Although the literature points to the TVI as a normal belly of the quadriceps, making it a "quinticeps", our analysis points to the TVI as a variation and probably a matter of regionality. However, the presence of TVI is not a rare case and cannot be disregarded, which makes this study important for anatomists, physiotherapists, physicians, and surgeons.

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Background: An increased number of breast cancer patients are challenged by acute and persistent treatment side effects. Oncology guidelines have been establishing physical exercise to counteract several treatment-related toxicities throughout cancer care. However, evidence regarding the optimal dose-response, feasibility, and the minimal resistance exercise volume and/or intensity remains unclear. The ABRACE Study will assess the impact of different resistance training volumes (i.e., single or multiple sets) combined with aerobic exercise on physical and psychological outcomes of breast cancer patients undergoing primary treatment. Methods: This study is a randomized, controlled, three-armed parallel trial. A total of 84 participants, aged ≥18 years, with breast cancer stages I-III, initiating adjuvant or neoadjuvant chemotherapy (≤50% of sessions completed) will be randomized to multiple sets resistance training plus aerobic training group, single set resistance training plus aerobic training group or control group. Neuromuscular and cancer-related fatigue (primary outcomes), muscle strength, muscle thickness, muscle quality by echo intensity, body composition, cardiorespiratory capacity, functional performance, upper-body endurance and quality of life will be measured before and after the 12-week intervention. Our analysis will follow the intention-to-treat approach and per-protocol criteria, with additional sub-group analysis. Discussion: Findings support prescribing exercise during chemotherapy for breast cancer and elucidate the potential role of different resistance training volumes as a management strategy for physical and psychological impairments in women with early-stage breast cancer. Our main hypothesis is for superiority in physical and psychological outcomes for both training groups compared to the control group, with no difference between single or multiple sets groups. Trial registration: Clinical trials NCT03314168.

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OBJECTIVE: To evaluate learning results of critical care physiotherapists participating in a muscle ultrasound (MUS) educational program. DESIGN: Cross-sectional study. SETTING: A custom-made 20-hour MUS course was performed over a 2-week time period, including knobs familiarization, patient positioning, anatomic landmarks, image acquisition, and limb muscle measurements. PARTICIPANTS: Nineteen critical care physiotherapists with little to no prior experience in ultrasound (N=19). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Theoretical knowledge, hands-on skills acquisition, and satisfaction were assessed. Inter- and intrarater reliability on landmarks, thickness, and pennation angle of quadriceps between participants was evaluated using intraclass correlation coefficients (ICCs). Reliability among instructors measured prior to the course was also reported as a reference. RESULTS: The percentage score (mean±SD) of knowledge questionnaires was 69±11 (pre-course), 89±10 (post-course), and 92±9 (hands-on skills). Course satisfaction scores ranged from 90%-100%. Pooled interrater reliability of participants (median ICC [interquartile range]) was good (0.70 [0.59-0.79]) for thickness, moderate (0.47 [0.46-0.92]) for landmarks, and absent (0.00 [0.00-0.05]) for pennation angle and the intrarater reliability was good (0.76 [0.51-0.91]) for thickness and weak (0.35 [0.29-0.52]) for pennation angle. Interrater ICC values for instructors were excellent (0.90) for thickness, good (0.67) for landmarks, and moderate (0.41) for pennation angle and intrarater ICC values were excellent (0.94) for thickness and good (0.75) for pennation angle. CONCLUSIONS: Although our sample was quite small and homogeneous, increased theoretical knowledge, high hands-on performance acquisition, and good satisfaction of physiotherapists were observed. Reliability was moderate to excellent for thickness and landmarks and absent to weak for pennation angle. Landmarking and pennation angle remain challenges for physiotherapist training in the application of MUS. Further studies are needed to identify variables that could modify reliability during MUS training.

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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.

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OBJECTIVES: The purpose of this study was to determine the association between functionality as assessed by the 6-minute walking test (6MWT), maximal voluntary contraction of the quadriceps (MVCQ), and quadriceps thickness and echo intensity as measured by sonography, in patients with chronic obstructive pulmonary disease (COPD). METHODS: Maximal voluntary contraction of the quadriceps and the thickness and echo intensity of the rectus femoris and vastus intermedius were evaluated in 20 patients with COPD. Functionality was assessed by the 6MWT. Differences between the evaluated muscles were determined by the Student t test. Pearson and Spearman rank correlation coefficients were used to analyze relationships between variables of interest, according to data characteristics. Finally, multivariate regression models were applied. RESULTS: There was a positive correlation between MVCQ and rectus femoris and vastus intermedius thickness (r = 0.427; P = .030; r = 0.469; P= .018, respectively) and a negative correlation between MVCQ and rectus femoris and vastus intermedius echo intensity (r= -0.500; P= .012; r= -0.482; P= .016). No correlation was found between MVCQ and the 6MWT (r = 0.319; P = .085). Multivariate regression analysis showed that the rectus femoris echo intensity, vastus intermedius echo intensity, and vastus intermedius thickness explained 70% of the variance in the distance walked during the 6MWT. CONCLUSIONS: These results indicate that, in patients with COPD, both quadriceps force and exercise capacity are associated with quantitative (thickness) and qualitative (echo intensity) characteristics of the quadriceps. Consequently, comprehensive assessments of peripheral muscles should simultaneously include both measurements.

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