Dual energy X-ray absorptiometry (DXA) reliability and intraobserver reproducibility for segmental body composition measuring / Reproducibilidad de la absorciometría dual de rayos X (DXA) y la reproducibilidad intraobservador para la medición de la composición corporal segmentaria

Background: the measurement precision of body composition can interfere on the diagnosis and prescription of diseases' treatment. Furthermore, with regard to dual energy X-rays absorptiometry (DXA), there may be important differences between the measures of regions of interest (ROI) automatically performed by DXA or manually by an evaluator, which can cause measurement error and influence the evaluation or diagnosis. Aim: thus, this study aimed to evaluate the measurement reliability of body composition by DXA and intraobserver reproducibility for the ROI measurement. Methods: a total of 15 young adults were subjected to two full-body scans by DXA, under the same conditions. The first scan of all volunteers was chosen and the extent of the ROI was performed, in two stages, separated by a period of 2 weeks, by a single trained evaluator. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated with a significance level of p < 0.05. Results: high-precision measurements of DXA for whole body mass (ICC = 0.999; CV = 2.3%), fat mass (ICC = 0.998; CV = 1.6%), lean mass (ICC = 0.995; CV = 0.3%) and bone mineral content (ICC = 0.996; CV < 0.1%) were obtained. Further, it was observed high intraobserver reproducibility for ROI measurement, with ICC values ranging between 0.952 and 0.999. Conclusion: body composition measurement by DXA presents high reproducibility for whole body mass, fat mass, lean mass and bone mineral content and also high intraobserver reproducibility for the ROI measurement

Introducción: la precisión de las medidas de la composición corporal puede interferir en el diagnóstico y prescripción del tratamiento de las enfermedades. Además, con respecto a la absorciometría dual de rayos X (DXA), pueden existir diferencias importantes entre las medidas de regiones de interés (ROI) realizadas automáticamente por DXA o manualmente por un evaluador, lo que puede causar error de medición e influir en la evaluación o diagnóstico. Objetivo: evaluar la reproducibilidad de la medida de la composición corporal por DXA y la reproducibilidad intraobservador para la medición de las ROI. Métodos: quince adultos jóvenes fueron sometidos a dos exploraciones de cuerpo completo por DXA, en las mismas condiciones. Se escogió la primera exploración de los voluntarios y se realizó la extensión de las ROI en dos etapas, separadas por un periodo de 2 semanas, por un solo evaluador capacitado. El coeficiente de variación (CV) y el coeficiente de correlación intraclase (ICC) se calcularon con un nivel de significación de p < 0,05. Resultados: la DXA presentó alta precisión para las medidas de la masa corporal total (ICC = 0.999, CV = 2.3%), masa grasa (ICC = 0.998, CV = 1.6%), masa magra (ICC = 0.995, CV = 0.3%) y hueso (ICC = 0,996, CV < 0,1%). Además, se observó una alta reproducibilidad intraobservador para la medida de las ROI, con valores de ICC entre 0,952 y 0,999. Conclusión: la medida de la composición corporal por DXA presenta alta reproducibilidad para todos los componentes y también alta reproducibilidad intraobservador para la medida de las ROI

Effects of Classic Progressive Resistance Training Versus Eccentric-Enhanced Resistance Training in People With Multiple Sclerosis.

OBJECTIVE: To compare the effects of classic progressive resistance training (PRT) versus eccentric strength-enhanced training (EST) on the performance of functional tests and different strength manifestations in the lower limb of people with multiple sclerosis (PwMS). DESIGN: Experimental trial. SETTING: Strength training program. PARTICIPANTS: PwMS (N=52; 19 men, 33 women) belonging to MS associations from the Castilla y León, Spain. INTERVENTIONS: Participants were assigned to 1 of 2 groups: a control group that performed PRT or an experimental group that performed EST. In both groups, the knee extensor muscles were trained for 12 weeks. MAIN OUTCOME MEASURES: Before and after 12 weeks of training, maximal voluntary isometric contraction and 1 repetition maximum (1RM) of the knee extensors were evaluated, as were the Chair Stand Test (CST) and Timed 8-Foot Up and Go (TUG) functional tests. RESULTS: No differences were found between the groups in the initial values for different tests. Intragroup comparisons found significant differences in CST (F=69.4; P<.001), TUG (F=40.0; P<.001), and 1RM (F=57.8; P<.001). For intergroup comparisons, EST presented better results than PRT in the CST (EST, 4.7%±2.8%; PRT, 1.9%±2.8%; F=13.1; P=.001) and TUG (EST, -2.9±4.7; PRT, -.41±5.6; F=5.6; P=.022). CONCLUSIONS: In PwMS, EST leads to improvements in 1RM, TUG, and CST that are similar to those of PRT. However, for patients who participated in this study, the EST seems to promote a better transfer of strength adaptations to the functional tests, which are closer to daily-living activities.

Métodos de evaluación de la masa muscular: una revisión sistemática de ensayos controlados aleatorios / Methods of evaluation of muscle mass: a systematic review of randomized controlled trials

Introducción: en los últimos años las investigaciones sobre la masa muscular han cobrado popularidad por su relación con la salud. Así, la medición precisa de la masa muscular puede tener aplicación clínica, ya que puede interferir en el diagnóstico y prescripción del tratamiento medicamentoso o no medicamentoso. Objetivo: realizar una revisión sistemática de los métodos más utilizados para la evaluación de la masa muscular en ensayos controlados aleatorios, con sus ventajas y desventajas. Método: se llevó a cabo una búsqueda en las bases de datos Pubmed, Web of Science y Scopus, con las palabras muscle mass, measurement, assessment y evaluation, combinadas de esta manera: 'muscle mass' AND (measurement OR assessment OR evaluation). Resultados: 23 estudios fueron recuperados y analizados, todos ellos en inglés. El 69,56% utilizaron solamente un método para la cuantificación de la masa muscular; el 69,57% utilizaron la doble absorciometría de rayos X (DXA); en el 45,46% el tipo de medida utilizado fue la masa corporal total libre de grasa; y el 51,61% eligieron el cuerpo total como sitio de medida. Conclusiones: en los ensayos controlados aleatorios analizados la mayor parte utilizó apenas un método de evaluación, siendo la DXA el método más empleado, la masa corporal total libre de grasa el tipo de medida más utilizado y el cuerpo total el sitio de medida más común (AU)

Introduction: in recent years, research about muscle mass has gained popularity for their relationship to health. Thus precise measurement of muscle mass may have clinical application once may interfere with the diagnosis and prescription drug or drug treatment. Objective: to conduct a systematic review of the methods most used for evaluation of muscle mass in randomized controlled trials, with its advantages and disadvantages. Methods: we conducted a search of the data bases PubMed, Web of Science and Scopus, with words 'muscle mass', 'measurement', 'assessment' and 'evaluation', combined in this way: 'muscle mass' AND (assessment OR measurement OR evaluation). Results: 23 studies were recovered and analyzed, all in English. 69.56% only used a method for quantification of muscle mass; 69.57% used dual X-ray absorptiometry (DXA); in 45.46% the type of measure used was the body lean mass; and 51.61% chose the whole body as a site of measurement. Conclusions: in the randomized controlled trials analyzed the majority used just one method of assessment, with the DXA being the method most used, the body lean mass the measurement type most used and total body the most common site of measure (AU)