Fat-free mass and maturity status are determinants of physical fitness performance in schoolchildren and adolescents

Abstract Objectives: The objective of the study was to verify whether (FFM), maturity status (MS) and chronological age (CA) are determinants of physical fitness performance, and to analyze FFM and physical performance aligned by CA and MS in children and adolescents. Methods: A descriptive correlational study was carried out in 863 schoolchildren. Weight, height, and waist circumference (WC) were evaluated. Body mass index (BMI), FFM, fat mass (FM), MS (Age at peak height velocity, APHV) were calculated. The physical tests of velocity 20 m, agility 5 m × 10rep, and horizontal jump (HJ) were evaluated. Results: The APHV was estimated in boys at 14.0 ± 0.36APHV and in girls at 11.96 ± 0.49APHV. The relationships between CA and APHV with FFM was r = 0.80 in boys and r = 0.44 to 0.45 in girls. The relationships between FFM and physical tests in boys were [HJ (r = 0.70), agility 5m × 10rep (r = -0.68), velocity (r = -0.61)] and in girls [HJ (r = 0.42), agility 5m × 10rep (r = -0.52), velocity (r = -0.20)]. The differences in FFM and physical fitness tests were more pronounced when aligned by APHV than by CA. Conclusion: It was verified that both FFM, CA, and APHV are determinants of physical fitness performance. In addition, the APHV should be introduced in physical education as a means of ranking physical performance among schoolchildren.

Comparación de parámetros antropométricos y de composición corporal de futbolistas profesionales / A Comparison of Anthropometric Parameters and the Body Composition of Professional Soccer Players

Resumen El presente estudio tuvo por objetivo comparar los parámetros antropométricos y de composición corporal en futbolistas profesionales en cinco temporadas. Se efectuó un estudio transversal (comparativo). Se estudió a 120 futbolistas, donde cada cohorte por año se evaluó a 24 futbolistas. El rango de edad fue de 18 a 37 años. Se evaluó a los futbolistas al inicio de cada temporada en los años 2012 a 2016: Se midió el peso, la estatura, seis pliegues cutáneos (Tríceps, subescapular, supra-iliaco, abdominal, muslo y pantorrilla). Se calculó el Índice de Masa corporal IMC, % de grasa, la masa grasa y masa libre de grasa MLG. El tejido adiposo se agrupó en tres grupos (brazo: (tricpes+subescapular, tronco: suprailiaco+abdominal, Piernas: muslo+pantorrilla). Hubo diferencias en el peso corporal, la estatura, la sumatoria de los 6 pliegues y la MLG a lo largo de los 5 años. [año 2012 (Peso: 76,6±7.8kg, estatura: 177.6±5.7cm, Pliegues: 58.7±12.8mm, MLG: 64.5±6.3mm), año 2013: (Peso: 77.8±6.4kg, Estatura: 178,4±4.4, Pliegues: 60.1±15.9mm, MLG:66.3±3.5mm), año 2014: (Peso: 74.9±5.7kg, Estatura: 177.0±5.8cm, Pliegues: 54.4±14.7mm, MLG: 64.5±4.5kg), año 2015: (Peso: 74.1±6.8kg, Estatura: 176.1±5.5cm, Pliegues: 54.9±15.6mm, MLG: 63.8±4.6kg), año 2016: (Peso: 72.7±kg, Estatura: 175.3±6.9kg, Pliegues: 50.8±12.mm, MLG: 62.8±5.9kg)]. Este estudio verificó que el perfil antropométrico y el tejido adiposo de los futbolistas fueron disminuyendo en cada temporada, mientras que la MLG reflejó similares valores en cada uno de las cohortes evaluadas.

Abstract The present cross-sectional (comparative) study aimed to compare the anthropometric and body composition parameters in professional soccer players over five seasons. It was conducted on 120 soccer players grouped in a cohort of 24 subjects per year. The age range was 18 to 37 years. The footballers were evaluated at the beginning of each season from 2012 to 2016; weight, height, six skin folds (triceps, subscapularis, supra-iliac, abdominal, thigh, and calf) were evaluated from 2012 to 2015. The Body Mass Index (BMI), fat percentage, fat mass, and FFM were calculated. The adipose tissue was grouped into three groups: arm (triceps + subscapular), trunk (supra iliac + abdominal), and legs (thigh + calf). Body weight, height, the sum of the 6 folds, and the MLG varied during the 5 years. For 2012 the results were the following: Weight, 76.6 ± 7.8kg; Height, 177.6 ± 5.7cm; Folds, 58.7 ± 12.8mm; MLG, 64.5 ± 6.3mm). In 2013, these were the results: Weight, 77.8 ± 6.4kg; Height, 178, 4 ± 4.4; Folds, 60.1 ± 15.9mm; MLG, 66.3 ± 3.5mm). These were the measures obtained in 2014: Weight, 74.9 ± 5.7kg; Height, 177.0 ± 5.8cm; Folds, 54.4 ± 14.7mm; MLG, 64.5 ± 4.5kg ). And these were of the year 2015: Weight, 74.1 ± 6.8kg; Height, 176.1 ± 5.5cm; Folds, 54.9 ± 15.6mm; MLG, 63.8 ± 4.6kg). Finally, in 2016 these were the measures collected: Weight, 72.7 ± kg; Height, 175.3 ± 6.9 kg; Folds, 50.8 ± 12.mm; MLG, 62.8 ± 5.9kg. This study verified that the soccer players' anthropometric profile and adipose tissue decreased each season, while the MLG reflected similar values in each of the evaluated cohorts.

Resumo O presente estudo teve como objetivo comparar os parâmetros antropométricos e de composição corporal em jogadores profissionais de futebol durante cinco temporadas. Foi realizado um estudo transversal (comparativo). Foi estudado um total de 120 jogadores de futebol, onde cada coorte por ano foram avaliados 24 jogadores. A faixa etária era de 18 a 37 anos. Os futebolistas foram avaliados no início de cada temporada, nos anos de 2012 a 2016. Foram medidas altura, peso, seis dobras da pele (tríceps, subescapular, supra ilíaca, abdominal, coxa e calcanhar). Foram calculados índice de massa corporal IMC, % de gordura, massa de gordura e massa livre de gordura MLG. O tecido adiposo foi agrupado em três grupos (braço: tríceps + subescapular, tronco: suprailíaco + abdominal, pernas: coxa + calcanhar). Houve diferenças no peso corporal, na altura, a soma de 6 dobras e a MLG ao longo dos 5 anos: ano 2012 (Peso: 76,6±7,8kg, Altura: 177,6±5,7cm, Dobras: 58,7±12,8mm, GLM: 64,5±6,3mm), ano 2013 (Peso: 77,8±6,4kg, Altura: 178,4±4,4, Dobras: 60,1±15,9mm, GLM:66,3±3.5mm), ano 2014 (Peso: 74,9±5,7kg, Altura: 177,0±5,8cm, Dobras: 54,4±14,7mm, GLM: 64,5±4,5kg), ano 2015 (Peso: 74,1±6,8kg, Altura: 176,1±5,5cm, Dobras: 54,9±15,6mm, GLM: 63,8±4,6kg), ano 2016 (Peso: 72,7±kg, Altura: 175,3±6,9kg, Dobras: 50,8±12,mm, GLM: 62,8±5,9kg). Este estudo verificou que o perfil antropométrico e o tecido adiposo dos jogadores de futebol diminuíram em cada temporada, enquanto que a MLG refletiu valores similares em cada um dos coortes avaliados.

Reference values of the body composition of young chilean soccer players / Valores de referencia de la composición corporal de jóvenes futbolistas chilenos / Valores de referência da composição corporal de jovens futebolistas chilenos

ABSTRACT Objective: To analyze whether fat mass (FM) and fat-free mass (FFM) should be evaluated by chronological age and/or biological age and propose curves to classify the body composition of young Chilean soccer players. Methods: A cross-sectional descriptive study was developed. Six hundred and forty-two soccer players between 13.0 and 18.9 years of age were recruited. Body mass, height, trunk-cephalic height, and tricipital and subscapular skinfolds were evaluated. Biological maturation was determined using peak height velocity age (PHV) and the percentage of fat mass was estimated by regression equations. The reference percentiles were calculated using the LMS method. Results: The values of R2 were lower for chronological age (FM = 0.07% and FFM = 0.13%) than for biological age (FM = 0.31% and FFM = 0.50%). Eleven percentiles (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95 and p97) were calculated for FFM and FM. Conclusion: Biological age (PHV) is a better predictor of FFM and FM than chronological age. The references proposed can be used to monitor the body composition of young Chilean soccer players. Level of Evidence II; Diagnostic Study .

Resumen Objetivo: Analizar si la masa grasa (MG) y la masa libre de grasa (MLG) deben ser evaluadas por la edad cronológica y/o por la edad biológica, y proponer curvas para clasificar la composición corporal de jóvenes futbolistas chilenos. Métodos: Se elaboró un estudio descriptivo transversal. Fueron reclutados 642 futbolistas entre 13,0 y 18,9 años. Fueron medidas masa corporal, estatura, altura tronco-cefálica, pliegues cutáneos tricipital y subescapular. La madurez biológica fue determinada por la edad de pico de velocidad de crecimiento (EPVC) y el porcentual de masa grasa fue estimado por ecuaciones de regresión. Los percentiles de referencia fueron calculados por el método LMS. Resultados: Los valores de R2 para edad cronológica fueron menores (MG=0,07% y MLG=0,13%) en comparación con los valores para la edad biológica (MG=0,31% y MLG=0,50%). Fueron calculados 11 percentiles (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95 y p97) para la MLG y MG. Conclusión: La edad biológica (EPVC) es un predictor mejor de la MLG y de la MG que la edad cronológica. Las referencias propuestas pueden servir para monitorizar la composición corporal de jóvenes futbolistas chilenos. Nivel de evidencia II; Estudio de diagnóstico .

RESUMO Objetivo: Analisar se a massa gorda (MG) e a massa livre de gordura (MLG) devem ser avaliadas pela idade cronológica e/ou pela idade biológica, e propor curvas para classificar a composição corporal de jovens futebolistas chilenos. Métodos: Elaborou-se um estudo descritivo transversal. Foram recrutados 642 futebolistas entre 13,0 e 18,9 anos. Massa corporal, estatura, altura tronco-cefálica, dobras cutâneas tricipital e subescapular foram medidas. A maturação biológica foi determinada pela idade de pico de velocidade de crescimento (IPVC) e o percentual de massa gorda foi estimado por equações de regressão. Os percentis de referência foram calculados pelo método LMS. Resultados: Os valores de R2para idade cronológica foram menores (MG = 0,07% e MLG=0,13%) em comparação com os valores para a idade biológica (MG = 0,31% e MLG = 0,50%). Foram calculados 11 percentis (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95 e p97) para a MLG e MG. Conclusão: A idade biológica (IPVC) é um preditor melhor da MLG e da MG do que a idade cronológica. As referências propostas podem servir para monitorar a composição corporal de jovens futebolistas chilenos. Nível de evidência II; Estudo de diagnóstico .

Reproductibilidad de pruebas de competencia motriz y percentiles para niños y adolescentes que viven a altitud moderada del Perú / Reproducibility of motor competence tests and percentiles for children and adolescents living at moderate altitude in Peru

Objetivo. Evaluar la reproductibilidad de las pruebas de competencia motriz (CM) de transposición lateral y salto lateral, y estimar percentiles por edad y sexo para niños que viven a altitud modera del Perú.Método. Se efectuó un estudio descriptivo transversal en la provincia de Arequipa (Perú). Se evaluó el peso, la estatura y la circunferencia de cintura. Se calculó el índice de masa corporal e índice ponderal. Se evaluó la prueba de transposición lateral y salto lateral (ambas de la batería Kopfer test für Kinder).Resultados. La muestra estuvo constituida por 885 niñas y 897 niños de 6,0 a 16,9 años. El error técnico de medida intraevaluador para ambas pruebas de CM oscilaron entre 1,75 y 3,9 repeticiones en ambos sexos, mientras que el coeficiente de correlación intraclase fue de 0,77 a 0,99. Los límites de acuerdo oscilaron entre -7,3 y 6,8 repeticiones en ambas pruebas. Se estimaron percentiles 5º, 15º, 50º, 85º y 95º por el método Least-Mean-Square algorithm. Los puntos de corte adoptados para las pruebas CM fueron bajo: < p15; regular: de p15 a p85; y alto: > p85.Conclusión. Las pruebas de transposición lateral y salto lateral mostraron una elevada capacidad de reproductibilidad. Los percentiles propuestos pueden servir para valorar la CM y podrían ser incluidos y adaptados como indicadores de desempeño en la educación física.

Objective. To assess the reproducibility of two motor competence (MC) tests: moving sideways and jumping sideways, and to estimate age and sex percentiles for children living at moderate altitude in Peru.Method. This was a descriptive, cross-sectional study conducted in the province of Arequipa, Peru. Weight, height, and waist circumference were assessed. Body mass index and ponderal index were estimated. The moving sideways and jumping sideways tests were assessed (both from the Körper test für Kinder test battery).Results. The sample was made up of 885 girls and 897 boys aged 6.0-16.9 years. The intra-evaluator technical error of measurement for both MC tests ranged between 1.75 and 3.9 repetitions in both males and females, whereas the intraclass correlation coefficient was 0.77-0.99. Agreement limits ranged between -7.3 and 6.8 repetitions for both tests. The 5th, 15th, 50th, 85th, and 95th percentiles were estimated using the Least-Mean-Square algorithm. The cut-off points for MC tests were low: < p15; medium: p15-p85; and high: > p85. Conclusion. Moving sideways and jumping sideways showed a high capacity for reproducibility. The proposed percentiles may be useful to assess MC and could be included and adapted as performance indicators in physical education

Análisis bibliométrico de las funciones ejecutivas de adultos mayores en Iberoamérica / Bibliometric analysis of executive functions of older adults in Ibero-America

RESUMEN Objetivos: a) Verificar la cantidad de estudios efectuados en Iberoamérica sobre función ejecutiva (FE) en adultos mayores; b) Identificar los instrumentos utilizados para medir las FE en adultos mayores durante los años 2009-2018. Material y métodos: Se efectuó un estudio bibliométrico sobre las FE en adultos mayores de Iberoamérica. La búsqueda de información se hizo en las base de datos Scopus y Scielo. Se consideraron estudios iberoamericanos publicados en idioma español y portugués, utilizándose ocho palabras clave y cinco indicadores registrados. Resultados: Se identificaron un total de 12 investigaciones originales en seis países iberoamericanos (España, Argentina, Chile, Colombia, Cuba, y Perú). La mayor cantidad de investigaciones relacionadas con FE en asultos mayores tuvo lugar en los periodos 2009-2010 y 2013-2014. En estos estudios, se han utilizado varios instrumentos con el Trail Making Test (TMT) y la Frontal Assessment Battery (FAB) como los de uso más frecuente. Conclusiones: Parece existir un interés limitado por investigar las FE en adultos mayores de Iberoamérica. La mayoría de los estudios idntificados en esta indagación utilizaron como tests cognitivos el TMT y la FAB.

SUMMARY Objectives: a) To verify the number of studies on executive functions (EF) in older adults carried out in Ibero-America; b) To identify the instruments used to measure EF in older adults during the years 2009-2018. Material and methods: A bibliometric study on EF in older adults in Latin America was carried out through the Scopus and Scielo databases. Studies published in Spanish and Portuguese languages using eight keywords and five registered indicators. Results: Between 2009 and 2018, a total of 12 original investigations have been carried out in six Iberoamerican countries (Spain, Argentina, Chile, Colombia, Cuba, and Peru). Most EF-related investigations were reported duing the 2010-2009 and 2013-2014 periods. Several instruments were used, the Trail Making Test and the Frontal Assessment Battery being the most frequent. Conclusions: There seems to be a limited interest in investigating EF in older adults in Ibero-America. Most of these studies identified in this inquiry used the TMT and the FAB as cognitive tests.

Ultrasound reference values for the calcaneus of children and adolescents at moderate altitudes in Peru

Abstract Objective: a) Establish reference values for bone parameters by using the speed of sound (SOS, m/s) of broadband ultrasound attenuation (BUA, dB/MHz) and establish a bone quality index (BQI = αSOS + βBUA) for children and adolescents living in a region of moderate altitude, b) compare bone parameters with an international standard (with different ethnic, socio-economic, and lifestyle backgrounds) by using ultrasound of the calcaneus (heel bone) (QUS). Methods: A descriptive cross-sectional study was carried out with children and adolescents between the ages of 6.0 and 16.9 years old. The sample was selected randomly. A total of 1322 subjects were studied. Weight, height, and bone parameters, using ultrasound of the calcaneus, were evaluated SOS, BUA, and BQI. Body Mass Index BMI was calculated. Results: The average age of males was 11.44 ± 0.35 years old, and for females, it was 11.43 ± 0.35 years old. The students in this research showed slightly higher values of SOS, BUA, and BQI for both sexes when compared with the international reference (the 50th percentile). Percentiles were generated (P3, P10, P25, P50, P75, P90, and P97) using the LMS method [median (M), standard deviation (S), and power of the Box-Cox transformation (L)] by age and sex. Conclusion: The students living at a moderate altitude showed slightly higher values in bone parameters in relation to the international reference. This pattern depicted a population with a better state of bone health. The proposed percentiles may be used to categorize adequate to at risk bone parameters based on age and sex.

Efectos de un programa de entrenamiento de marcha sobre las capacidad aeróbica y la función cognitiva en mujeres diabéticas de edad avanzada

Background: Among older people, physical exercise improves cognitive function, aerobic fitness, and thus functional independence. Aim: To determine the effects of a walking training program on aerobic fitness and cognitive function in older women with type 2 diabetes mellitus. Material and Methods: An experimental study was carried out in 76 women with type 2 diabetes mellitus aged between 64 and 78 years. Thirty-eight women in the exercise group (EG) participated in a controlled walking program 3 times a week for 48 sessions (60min /day) and 38 women in the control group (CG) were not trained. Weight, height, body mass index (BMI), estimated maximal oxygen uptake (VO2max), and cognitive function using the Minimental test were evaluated at baseline and the end of the intervention. Results: The Minimental test improved significantly in the exercise group and did not change in the control group. Estimated VO-2max improved in women aged between 69 and 78 years. The distance walked in 6 minutes increased in all women of the experimental group. No changes in these parameters were observed in the control group. Conclusions: A structured walking program improved cognitive function, estimated aerobic capacity, and walking distance in these diabetic women.

La Preparación de los Maestros para Estimular la Socialización De los Educandos con Autismo en Condiciones de Inclusión / The Preparation of School Teachers to Stimulate the Socialization of Students with Autism in Conditions of Inclusion

RESUMEN: Los maestros de educación general han expresado su preocupación por la inclusión de educandos con Trastornos del Espectro Autista, debido a la falta de habilidades sociales de los niños, comportamientos estereotipados e intereses restringidos. El objetivo de este estudio es describir y comparar el estado actual de la preparación de los maestros de primaria para estimular la socialización de los educandos con Trastornos del Espectro Autista en escuelas inclusivas. A la luz de una metodología cuantitativa se realizó un estudio descriptivo-comparativo de corte transversal. Se estudiaron 74 maestros (52 mujeres y 22 hombres) encargados de cumplir con el rol docente-educativo de atender a los educandos con Trastornos del Espectro Autista en condiciones de inclusión en una provincia occidental de Cuba. El rango de edad oscila entre 22 y 57 años. Se aplicó un cuestionario y una Ficha de Observación previamente validados para medir la preparación teórica-metodológica y práctica de los maestros. Los resultados muestran que los maestros presentan dificultades para estimular la socialización de los educandos con autismo en escuelas inclusivas. Asimismo, el grado académico, la experiencia en espacios educacionales inclusivos y el área disciplinar resultaron ser variables sociodemográficas que determinan la preparación de los maestros para cumplir con esta tarea educativa. Estos resultados aportan información clave para diseñar estrategias y planes de acción, tanto en la formación inicial como en la práctica cotidiana, en aras de potenciar las competencias teóricas y prácticas de los maestros que asumen este desafío.

ABSTRACT: Basic Education teachers have expressed concern about the inclusion of learners with Autism Spectrum Disorder, due to children's lack of social skills, stereotypical behaviors, and restricted interests. The objective of this study was to describe and compare the current state of preparation of Elementary School teachers to stimulate the socialization of students with Autism Spectrum Disorder in inclusive schools. In the light of a quantitative methodology, a descriptive-comparative cross-sectional study was carried out. Seventy-four teachers (52 women and 22 men) in charge of fulfilling the teaching-educational role of attending to students with Autism Spectrum Disorder in conditions of inclusion in a Western province of Cuba were studied. The age ranged from 22 to 57 years. A previously validated questionnaire and Observation Sheet were applied to measure teachers' theoretical-methodological and practical preparation. The results show that teachers have difficulties in stimulating the socialization of learners with autism in inclusive schools. Likewise, the academic degree, the experience in inclusive educational spaces and the disciplinary area turned out to be sociodemographic variables that determine the preparation of the teachers to fulfill this educational task. These results provide key information to design strategies and action plans, both in initial training and in daily practice, in order to enhance the theoretical and practical skills of teachers who take on this challenge.

Fuerza muscular y porcentaje de grasa corporal en niños y adolescentes de la región del Maule, Chile / Muscle strength and body fat percentage in children and adolescents from the Maule region, Chile

Objetivo. Analizar la asociación entre la fuerza de prensión manual relativa (FPMR) y la masa grasa (MG), controlando el posible efecto del estado de madurez.Metodología. Se estudiaron niños y adolescentes de ambos sexos con un rango de edad de ≥ 7,5 a ≤ 15,49 años. Se evaluó la FPMR mediante un dinamómetro hidráulico manual. El porcentaje de MG se evaluó mediante la absorciometría de rayos X de doble energía. Para analizar las diferencias por sexo y grupo etario y entre los niños normopesos y obesos en los niveles de FPMR, se utilizó el análisis de covarianza. Se consideraron como covariable los años de pico de velocidad de crecimiento (estado de madurez). Para analizar la asociación entre los niveles de FPMR y MG, se utilizó la correlación parcial, controlando el año de pico de velocidad de crecimiento.Resultados. Participaron 1685 escolares (731 mujeres y 954 varones). Fueron conformados 4 grupos de edad (7,5-9,4 años; 9,5-11,4 años; 11,5-13,4 años y 13,5-15,4 años). La FPMR aumentó con la edad en ambos sexos. Los valores de MG fueron elevados en todos los grupos etarios. No hubo diferencias en los grupos 3 y 4 en las niñas y en el grupo 4 de los niños. Los niños clasificados como peso normal presentaron significativamente mayor FPMR que los obesos. Se observó una asociación negativa entre FPMR y MG.Conclusión. Se demostró que la FPMR estaba negativamente asociada con la MG, tras controlar el efecto del estado de madurez

Objective. To analyze the association between relative handgrip strength (RHGS) and fat mass (FM) after controlling for the potential effect of maturity status.Methodology. Both male and female children and adolescents aged ≥ 7.5 to ≤ 15.49 years were studied. RHGS was assessed using a hydraulic hand dynamometer. FM percentage was established using a dual-energy X-ray absorptiometry. Age and sex differences in RHGS levels between normal weight and obese participants were studied with an analysis of covariance. A covariate was years from peak height velocity (maturity status). The association between RHGS and FM levels was analyzed using a partial correlation and controlling for age at peak height velocity.Results. A total of 1685 students (731 girls and 954 boys) participated. Four age groups were established (7.5-9.4 years, 9.5-11.4 years, 11.5-13.4 years, and 13.5-15.4 years). RHGS increased with age in both males and females. FM values were high in all age groups. No differences were observed in groups 3 and 4 among girls or in group 4 among boys. Participants classified as normal weight showed a significantly higher RHGS than their obese peers. A negative association was noted between RHGS and FM.Conclusion. RHGS was shown to be negatively associated with FM after controlling for the effect of maturity status

Validez de ecuaciones y propuesta de valores referenciales para estimar la masa grasa de adultos mayores

Background: Excess fat mass (FM) has a higher risk of producing sarcopenia, physical deterioration and reduced quality of life in older people. Aim: To propose regression equations based on the Body Mass Index (BMI) to predict fat mass using double energy X-ray absorptiometry (DXA) as the gold standard. Material and Methods: Cross-sectional study in 1,188 participants (523 men and 665 women) aged 60 to 85 years. Ten percent of these (59 men and 60 women) were randomly selected to propose FM equations using DXA. The remaining 90% was used to calculate FM and develop percentiles. Results: Two equations were proposed to estimate FM [men: FM = −29,502+ (1,912 * BMI) R2 = 79%, women: FM = −9,891+ (1,323 * BMI) R2 = 80%]. Ten, 50, 85 and 95 percentiles were developed to evaluate FM. Conclusions: This study developed reliable regression equations and referential values to estimate FM in older people.

Pruebas de aptitud física que realizan los escolares / Physical fitness tests in schoolchildren

The objective was to determine the types of studies that have been carried out according to year and region and to verify the physical tests used according to physical fitness dimensions from 2010 to 2018. A systematic review was carried out. Physical fitness (study types and physical tests) was studied in Chile. The PubMed database was used, considering the period from 2010 to 2018. The keywords used in Spanish were: aptitud física, niños y adolescentes, Chile, and in English: physical aptitude, children and adolescents. The information was recorded on an observation sheet and for the data, the PRISM flow chart was used. 18 studies were identified. 88.9% are descriptive (cross-sectional) studies, 11.1% quasi-experimental. 38.9% were made in the Metropolitan region, 33.3% in Maule, 11% in Araucanía, 5.6% for each region of Los Lagos, Ñuble, and other unspecified regions. In the muscular dimension, it was determined that 38.9% used the manual clamping force and 50% the horizontal leap. In the cardiorespiratory dimension, 27.8% applied the Course-Navette test, 16.7% the 6-minute walk test, and 11% the 100-meter speed test. A high number of descriptive (cross-sectional) investigations were identified and the most commonly used physical tests were horizontal leap, manual clamping force, Course-Navette test, and 6-minute walk test. These results suggest the need to develop experimental and longitudinal studies, as well as the inclusion of morphological and motor dimensions in their protocols

El objetivo fue determinar los tipos de estudio que se han efectuado según año y región, y verificar las pruebas físicas utilizadas según dimensiones de la aptitud física durante 2010 a 2018. Se efectuó una revisión sistemática. Se estudió la aptitud física (tipos de estudio y pruebas físicas) en Chile. Se utilizó la base de datos PubMed, considerando el período 2010 a 2018. Las palabras clave utilizadas fueron, en español: aptitud física, niños y adolescentes, Chile, y en inglés: physical aptitude, children and adolescents. La información se registró en una ficha de observación y para la organización de datos se utilizó el diagrama de flujo PRISMA. Se identificaron 18 estudios. El 88.9% son de tipo descriptivo (transversales); el 11.1%, cuasiexperimentales. El 38.9% se efectuó en la región Metropolitana; el 33.3%, en El Maule; 11%, en la Araucanía; 5.6% para cada región de Los Lagos, Ñuble y no especificada. En la dimensión muscular, se determinó que el 38.9% utilizó la fuerza de prensión manual y el 50% el salto horizontal. En la dimensión cardiorrespiratoria, el 27.8% aplicó el test de Course Navette; el 16.7%, la caminata de 6 minutos, y el 11%, la prueba de velocidad de 100 metros. Se identificó un elevado número de investigaciones descriptivas (transversales) y las pruebas físicas más utilizadas fueron salto horizontal, fuerza de presión manual prueba de Course Navette y la caminata de 6 minutos. Estos resultados sugieren la necesidad de desarrollar estudios experimentales y longitudinales, así como la inclusión de dimensiones morfológicas y motoras en sus protocolos

Aerobic capacity of chilean adults and elderly: proposal of classification by regional percentiles / Capacidade aeróbia de adultos e idosos chilenos: proposta de classificação por percentis regionais / Capacidad aeróbica de adultos y ancianos chilenos: propuesta de clasificación por percentiles regionales

ABSTRACT Introduction Aerobic fitness is an important predictor that contributes to the preservation of functional independence during the aging process. Its measurement represents a fundamental tool in the identification of multiple health problems. Objective To compare the aerobic capacity of adults and elderly subjects through international studies and to develop percentiles by age group using the LMS method. Methods A cross-sectional descriptive study was conducted with 1146 subjects (437 men and 709 women). The age group of the sample ranged from 50 to 84 years. The subjects evaluated came from the physical activity programs offered by the National Sports Institute (IND) and by the city council of Talca (Chile). Body mass, stature, oxygen saturation (SatO2), six-minute walk test, and systolic and diastolic blood pressure were assessed. Body Mass Index (BMI) was calculated for both sexes. The LMS method was used to propose the percent distribution. Results Aerobic capacity decreases with age (28.5% for men and 29.9% for women). There was a negative relationship between age and the six-minute walk test (men r = -0.13 and women r = -0.39). There was a discrepancy between the elderly subjects in the current study and those from international studies. The normative data for the classification of aerobic fitness were expressed in percentiles (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95 and p97). Conclusion The aerobic performance of elderly subjects diminishes as they age; in addition, the current results differ from international studies, which motivated the development of percentiles to classify aerobic fitness in everyday situations, especially in places with few resources and particularly where field tests are considered a priority for large-scale physical evaluation. Level of evidence II; Diagnostic studies - investigation of diagnostic test.

RESUMO Introdução A aptidão aeróbia é importante preditor que contribui com a preservação da independência funcional à medida que se envelhece. Sua mensuração transforma-se em ferramenta fundamental na identificação de múltiplos problemas de saúde. Objetivo Comparar a capacidade aeróbia de adultos e idosos com estudos internacionais e desenvolver percentis por faixas etárias, utilizando o método LMS. Métodos Elaborou-se um estudo descritivo transversal com 1.146 sujeitos (437 homens e 709 mulheres). A faixa etária da amostra variou de 50 a 84 anos. Os sujeitos avaliados eram oriundos dos programas de atividade física oferecidos pelo Instituto Nacional de Desporto (IND) e pela prefeitura de Talca (Chile). Avaliaram-se massa corporal, estatura, saturação de oxigênio (SatO2), teste de caminhada de 6 minutos e pressão arterial diastólica e sistólica. Calculou-se o índice de massa corporal (IMC) para ambos os sexos. Utilizou-se o método LMS para propor a distribuição percentílica. Resultados A capacidade aeróbia diminui com o decorrer da idade (28,5% para os homens e 29,9% para as mulheres). Houve relação negativa entre a idade e o teste de caminhada de 6 minutos (homens: r = -0,13; mulheres: r = -0,39). Observou-se discrepância entre os idosos do presente estudo com os de estudos internacionais. Os dados normativos para a classificação da aptidão aeróbia foram expressos em percentis (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95 y p97). Conclusão Os idosos diminuem o desempenho aeróbio conforme a idade avança. Os presentes resultados diferem dos estudos internacionais, o que motivou o desenvolvimento dos percentis para classificar a aptidão aeróbia em situações cotidianas, especialmente em locais com poucos recursos e principalmente onde os testes de campo são considerados prioritários para avaliação física em larga escala. Nível de evidência II; Estudos diagnóstico - investigação de teste diagnóstico.

RESUMEN Introducción La aptitud aeróbica es un importante predictor que contribuye con la preservación de la independencia funcional a medida que se envejece. Su medición se transforma en una herramienta fundamental en la identificación de múltiples problemas de salud. Objetivo Comparar la capacidad aeróbica de adultos y ancianos con estudios internacionales y desarrollar percentiles por grupos de edad utilizando el método LMS. Métodos Se elaboró un estudio descriptivo transversal con 1146 sujetos (437 hombres y 709 mujeres). El grupo de edad de la muestra varió de 50 a 84 años. Los sujetos evaluados eran oriundos de los programas de actividad física ofrecidos por el Instituto Nacional de Deporte (IND) y por la Municipalidad de Talca (Chile). Se evaluaron masa corporal, estatura, saturación de oxígeno (SatO2), test de seis minutos de caminata y presión arterial diastólica y sistólica. Se calculó el índice de masa corporal (IMC) para ambos sexos. Se usó el método LMS para proponer la distribución de percentil. Resultados La capacidad aeróbica disminuye con el transcurso de la edad (28,5% para los hombres y 29,9% para las mujeres). Hubo relación negativa entre la edad y el test de caminata de seis minutos (hombres r= -0,13 y mujeres r= -0,39). Se observó discrepancia entre los ancianos del presente estudio con los de estudios internacionales. Los datos normativos para la clasificación de la aptitud aeróbica fueron expresados en percentiles (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95 y p97). Conclusión Los ancianos disminuyen el rendimiento aeróbico conforme avanza la edad. Los presentes resultados difieren de los estudios internacionales, lo que motivó el desarrollo de los percentiles para clasificar la aptitud aeróbica en situaciones cotidianas, especialmente en locales con pocos recursos y principalmente donde los tests de campo son considerados prioritarios para la evaluación física a larga escala. Nivel de Evidencia II; Estudios diagnóstico-investigación de test diagnóstico.

Body mass index and physical fitness in Brazilian adolescents / Índice de massa corporal e aptidão física em adolescentes brasileiros

Abstract Objective: Evaluate the relationship between body mass index and physical fitness in a cross-sectional sample of Brazilian youth. Methods: Participants were 3849 adolescents (2027 girls) aged 10 -17 years. Weight and height were measured; body mass index was calculated. Physical fitness was evaluated with a multistage 20 m shuttle run (cardiovascular endurance), standing long jump (power), and push-ups (upper body strength). Participants were grouped by sex into four age groups: 10 -11, 12 -13, 14 -15, and 16 -17 years. Sex-specific ANOVA was used to evaluate differences in each physical fitness item among weight status categories by age group. Relationships between body mass index and each physical fitness item were evaluated with quadratic regression models by age group within each sex. Results: The physical fitness of thin and normal youth was, with few exceptions, significantly better than the physical fitness of overweight and obese youth in each age group by sex. On the other hand, physical fitness performances did not consistently differ, on average, between thin and normal weight and between overweight and obese youths. Results of the quadratic regressions indicated a curvilinear (parabolic) relationship between body mass index and each physical fitness item in most age groups. Better performances were attained by adolescents in the mid-range of the body mass index distribution, while performances of youth at the low and high ends of the body mass index distribution were lower. Conclusion: Relationships between the body mass index and physical fitness were generally nonlinear (parabolic) in youth 10 -17 years.

Resumo Objetivo: Avaliar a relação entre o índice de massa corporal e a aptidão física em uma amostra transversal de jovens brasileiros. Métodos: Os participantes foram 3.849 adolescentes (2.027 meninas) entre 10-17 anos. Foram medidos o peso e a estatura e foi calculado o índice de massa corporal. A aptidão física foi avaliada com: a corrida vaivém de 20 metros de vários estágios (resistência cardiovascular), impulsão horizontal (energia) e flexões (força superior do corpo). Os participantes foram agrupados por sexo em quatro faixas etárias: 10-11, 12-13, 14-15 e 16-17 anos. A Anova específica para sexo foi usada para avaliar as diferenças em cada item de aptidão física entre as categorias de status do peso por faixa etária. As relações entre o índice de massa corporal e cada item de aptidão física foram avaliadas com os modelos de regressão quadrática por faixa etária com relação ao sexo. Resultados: A aptidão física de jovens magros e normais foi, com poucas exceções, significativamente melhor do que a aptidão física de jovens com sobrepeso e obesos em cada faixa etária por sexo. Por outro lado, os desempenhos na aptidão física não diferiram de forma consistente, em média, entre jovens magros e com peso normal e entre jovens com sobrepeso e obesos. Os resultados das regressões quadráticas indicaram uma relação curvilínea (parabólica) entre o índice de massa corporal e cada item de aptidão física na maior parte das faixas etárias. Os melhores desempenhos foram obtidos pelos adolescentes na faixa intermediária da distribuição do índice de massa corporal, ao passo que os desempenhos dos jovens nas extremidades inferiores e superiores da distribuição do índice de massa corporal foram menores. Conclusão: As relações entre o índice de massa corporal e a aptidão física foram, em geral, não lineares (parabólica) nos jovens entre 10-17 anos.

Evaluación de los trastornos del sueño y propuesta de percentiles para los adolescentes / Assessment of sleep disorders and proposed percentiles for adolescents

Objetivos. Los objetivos del estudio fueron los siguientes: a) construir un instrumento válido y confiable que evaluara, por autoinforme, los trastornos del sueño en adolescentes escolares chilenos y b) desarrollar valores percentílicos según la edad y el sexo. Metodología. Se efectuó un estudio de tipo descriptivo de corte transversal en 2310 adolescentes escolares de la Región del Maule, Chile. Se construyó el autoinforme de trastornos del sueño considerando cinco categorías (duración, alteraciones, problemas en la respiración, fatiga y uso de estimulantes). Se validó por medio del análisis factorial confirmatorio. La fiabilidad se evaluó por la consistencia interna. Se crearon percentiles a través del método LMS (L: asimetría, M: mediana y S: coeficiente de variación). Resultados. Las preguntas 3, 9 y 12 presentaron saturaciones inferiores a 0,40, y las demás preguntas reflejaron saturaciones superiores a 0,41. El valor de adecuación Kaiser-Meyer-Olkin fue 0,749 y la prueba de esfericidad de X2= 4790,09; el porcentaje de la varianza explicó el 62,1 %. El alfa de Cronbach mostró valores entre 0,71 y 0,76. Conclusión. El autoinforme desarrollado para medir los trastornos del sueño en los adolescentes puede ser aplicado de forma válida y confiable en programas de ciencias de la salud, de la educación y del deporte. Se sugiere el uso de percentiles para identificar los patrones normales y/o trastornos del sueño por edad y género.

Objectives. The objectives of this study included: a) to develop a valid and reliable self-reporting instrument to assess sleep disorders among Chilean adolescent students and b) to develop percentiles for age and sex. Methodology. This was a descriptive, crosssectional study in 2310 adolescent students conducted in the Maule Region, Chile. The sleep disorder self-report was developed considering five categories: duration, alterations, breathing problems, fatigue, and stimulant use. The instrument was validated using a confirmatory factor analysis. Reliability was assessed based on internal consistency. Percentiles were developed using the LMS method (L: lambda, asymmetry; M: mu, median; S: sigma, coefficient of variation). Results. Questions 3, 9, and 12 showed saturation values below 0.40, while the rest had saturation values above 0.41. The Kaiser-Meyer-Olkin measure of adequacy was 0.749 and the test of sphericity X2 was 4790.09; the percentage of variance accounted for 62.1%. Cronbach's alpha ranged between 0.71 and 0.76. Conclusion. The self-report developed to measure sleep disorders in adolescents is valid and reliable for its use in health, education, and sports science programs. Percentiles should be used to identify normal patterns and/or sleep disorders by sex and age.

Relación entre adiposidad corporal y salto horizontal en niños y adolescentes escolares / Relationship between body adiposity and horizontal jump in school children and adolescents

Resumen: Un alto nivel de aptitud física en la infancia y la adolescencia se asocia con resultados de salud física y mental más favorables. Objetivo: Comparar la adiposidad corporal y el salto horizontal con estudios internacionales y analizar la relación entre indicadores de adiposidad corporal y salto horizontal en niños y adolescentes. Pacientes y Método: Estudio descriptivo en 812 adolescentes de Talca (Chi le), con un rango de edad entre 10,0 a 16,9 años. Se evaluó el peso, estatura, la circunferencia de la cintura (CC) y el Salto Horizontal (SH) previo calentamiento de 10-15 minutos para evaluar la fuerza explosiva de las extremidades inferiores según protocolo de Castro-Piñero et al. Se comparó la adiposidad y el SH con estudios nacionales e internacionales. La normalidad de los datos fue ve rificada por el test de Kolmogorov-Smirnov. Se crearon curvas de percentiles (p50) suavizadas para el IMC, CC y SH para cada sexo según el método LMS. Resultados: Los adolescentes mostraron discrepancias en la adiposidad corporal y en el desempeño del SH con los estudios internacionales. En ambos sexos se verificaron correlaciones negativas y significativas entre el IMC y el SH (hom bres r= -0,104 y mujeres r= -0,149) y entre la CC y el SH (hombres r= -0,100 y mujeres r= -0,131). Los adolescentes que fueron clasificados en el tercil 1 (bueno) y tercil 2 (satisfactorio) presentaron menor adiposidad corporal (IMC y CC) y mejor desempeño en el SH en relación a los del tercil 3 (pobre). Conclusión: Se observó mayor adiposidad corporal y menor desempeño en el SH respecto a los estudios internacionales. Además, se verificó una relación negativa entre adiposidad corporal y SH. Estos hallazgos sugieren que el aumento progresivo de la adiposidad conforme la edad aumenta limita negativamente el desempeño de la fuerza de las extremidades inferiores de los niños y ado lescentes estudiados.

Abstract: A high level of physical fitness in childhood and adolescence is associated with more favorable phy sical and mental health outcomes. Objective: To compare body adiposity and horizontal jump per formance with international studies and to analyze the relationship between body adiposity and ho rizontal jump performance indicators in children and adolescents. Patients and Method: Descriptive study conducted on 812 adolescents from Talca (Chile), with an age range between 10.0 and 16.9 years. Weight, height, waist circumference (WC) and Horizontal jump (HJ) were evaluated after warm-up for 10 to 15 minutes to evaluate the explosive strength of the lower extremities according to the protocol of Castro-Piñero et al. Adiposity and HJ were compared with national and international studies. The data normality was verified by the Kolmogorov-Smirnov test. Smoothed percentile cur ves (p50) were created for BMI, WC, and HJ for each gender according to the LMS method. Results: Adolescents showed differences in body adiposity and HJ performance with international studies. In both genders, negative and significant correlations were found between the BMI and the HJ (men r = -0.104 and women r = -0.149) and between the WC and the HJ (men r = -0.100 and women r = -0.131). The adolescents who were classified in tertile 1 (good) and tertile 2 (satisfactory) had lower body adiposity (BMI and WC) and better HJ performance than those in tertile 3 (poor). Conclusion: Higher body adiposity and lower HJ performance were observed compared to international studies. In addition, a negative relationship between body adiposity and HJ was found. These findings suggest that the progressive increase of adiposity as age increases negatively affects the strength performance of the lower extremities of the studied children and adolescents.

Crecimiento físico en jóvenes futbolistas chilenos: propuesta de percentiles por edad cronológica y biológica / Physical growth in young Chilean football players: Proposal of percentiles based on chronological and biological age

Objetivos. a) Comparar el crecimiento físico con la referencia americana de los Centros para el Control y la Prevención de Enfermedades (Centers for Disease Control and Prevention, CDC) 2012; b) analizar el crecimiento físico por edad cronológica y biológica; c) proponer curvas de crecimiento físico por edad cronológica y biológica. Metodología. Se efectuó una investigación descriptiva (transversal) en jóvenes futbolistas de Chile sobre peso, estatura de pie y estatura sentada. Se compararon con las referencias del CDC-2012. Se desarrollaron percentiles por medio del método LMS. Resultados. Se estudió a 642 jóvenes futbolistas chilenos de 13,0-18,9 años. Su peso corporal fue inferior al CDC desde los 13,0 hasta los 18,9 años (p < 0,05), mientras que, en la estatura, no hubo diferencias significativas a edades iniciales (13,013,9 y 14,0-14,9 años). Las diferencias empezaron a aparecer desde los 15,0 hasta los 18,9 años (p < 0,05). Por edad cronológica, el peso explicó 31%; la estatura de pie, 16% y estatura sentada, 0,09%, mientras que, por edad biológica, el peso explicó 51%; la estatura de pie, 40% y estatura sentada, 54%. Se desarrollaron percentiles por edad cronológica y biológica. Conclusión. Estos jóvenes difieren en sus patrones de crecimiento físico en relación con el CDC-2012. Su evaluación refleja mejores porcentajes de explicación por edad biológica que por edad cronológica. Los percentiles propuestos pueden ser una alternativa para seguir la trayectoria de crecimiento físico de jóvenes futbolistas en contextos deportivos a corto, mediano y largo plazo.

Objectives. a) To compare physical growth to the 2012 American standard from the Centers for Disease Control and Prevention (CDC); b) to analyze physical growth by chronological and biological age; c) to propose physical growth charts based on chronological and biological age. Methodology. A descriptive (cross-sectional) study was conducted in young Chilean football players based on weight, standing height, and sitting height. These were compared to the CDC-2012 standard. Percentiles were developed using the LMS method. Results. A total of 642 young Chilean football players aged 13.0-18.9 years were studied. Their body weight was lower than that of the CDC standard from 13.0 to 18.9 years old (p < 0.05), whereas their height showed no significant differences in the initial age categories (13.013.9 and 14.0-14.9 years). Differences started to be observed as of 15.0 years old up to 18.9 years old (p < 0.05). In relation to chronological age, weight explained 31%; standing height, 16%; and sitting height, 0.09%, whereas in relation to biological age, weight explained 51%; standing height, 40%; and sitting height, 54%. Percentiles were developed based on chronological and biological age. Conclusion. These youth showed different physical growth patterns compared to the CDC-2012 standard. Their assessment reflects better explanatory percentages for biological age than for chronological age. The proposed percentiles may be an alternative to keep track of the physical growth patterns of young football players in sports settings in the short, medium, and long term.

Peso, estatura e índice de masa corporal de niños y adolescentes de moderada altitud de Colombia / Weight, height and body mass index of children and adolescents living at moderate altitude in Colombia

Introducción. Existe preocupación progresiva por estudiar el crecimiento físico de diversas regiones del mundo, aunque no se considera la altitud como factor de ajuste. Objetivos. Comparar variables de crecimiento físico y patrones de índice de masa corporal (IMC) con la referencia del Centro para el Control y Prevención de Enfermedades 2012 (CDC según siglas en inglés) y desarrollar percentiles para niños y adolescentes. Metodología. Se investigaron escolares de moderada altitud de Bogotá (Colombia). Se evaluó el peso, la estatura y se calculó el IMC. Las variables antropométricas fueron comparadas con referencia al CDC-2012, Brasil, Perú y Argentina. Se construyeron curvas por el método LMS (least-mean-square algorithm). Resultados. Se estudió a 2241 escolares (1159 mujeres), entre 6,0 y 17,9 años. No hubo diferencias significativas en el peso e IMC entre 6 y 8 años con relación al CDC-2012; sin embargo, desde los 9 a 17 años, esta muestra evidenció valores inferiores de peso e IMC en relación con el CDC-2012. En la estatura, en ambos sexos, se mostraron valores inferiores del CDC-2012. Las comparaciones con las curvas regionales de Argentina, Perú y Brasil fueron relativamente similares, excepto en el IMC en mujeres, que presentron valores inferiores desde 13 a 17 años. Conclusión. Las variables de crecimiento de los escolares fueron inferiores con referencia al CDC-2012. Hubo ligeras discrepancias en el crecimiento físico y en el IMC con las curvas de Argentina, Brasil y Perú. Se construyeron curvas para evaluar el crecimiento y el IMC de escolares de moderada altitud de Colombia.

Introduction. There is increasing concern over the study of physical growth in different regions of the world, although altitude is not considered an adjustment factor. Objectives. Compare physical growth variables and body mass index (BMI) patterns with the Centers for Disease Control and Prevention (CDC) 2012 reference data and develop percentiles for children and adolescents. Methodology. School children living at moderate altitude in Bogotá (Colombia) were studied. Their weight and height were evaluated and their BMI was calculated. Anthropometric variables were compared against reference data of the CDC-2012, Brazil, Peru and Argentina. Curves were constructed using the least mean square (LMS) method. Results. A total of 2241 school children (1159 girls) aged 6.0 to 17.9 years were included. There were no significant differences in weight and BMI in 6 to 8 year-olds relative to CDC-2012 reference data; in 9 to 17 year-old children, however, this sample evidenced lower values in terms of weight and BMI as compared to those of the CDC-2012. As far as height is concerned, in both sexes, values were lower than those of the CDC-2012. Comparisons against the regional curves of Argentina, Peru and Brazil yielded relatively similar results, with the exception of girls' BMI, as 13 to 17 year-old girls exhibited lower values. Conclusion. Growth variables of school children were lower relative to the CDC-2012 reference data. There were slight discrepancies in physical growth and BMI in relation to the curves of Argentina, Peru and Brazil. Curves were constructed to evaluate growth in school children living at moderate altitude in Colombia.

Desarrollo de ecuaciones y propuesta de valores referenciales para estimar la masa grasa de niños y adolescentes chilenos / Development of equations and proposed reference values to estimate body fat mass among Chilean children and adolescents

Introducción. La evaluación de la composición corporal es relevante para determinar el estado nutricional e identificar posibles riesgos para la salud. Objetivo. a) Desarrollar ecuaciones de regresión para predecir la masa grasa (MG) utilizando como método de referencia la absorciometría de rayos X de doble energía; b) proponer valores referenciales de MG en función de la edad cronológica y biológica para niños y adolescentes chilenos. Metodología. Estudio transversal en niños y adolescentes de 5,0 a 18,9 años de la región del Maule (Chile). La muestra fue conformada de forma probabilística (estratificada) por 3593 sujetos. Se evaluó el peso, estatura de pie, estatura sentada y circunferencia de la cintura. Se calculó el índice de masa corporal y los años de pico de velocidad del crecimiento (APVC). La composición corporal (MG, masa libre de grasa, masa ósea y porcentaje de grasa) fueron determinados por medio del escaneo de absorciometría de rayos X de doble energía. Resultados. Los APVC (edad biológica) se presentaron en los hombres a los 14,9 ± 0,9 APVC y, en las mujeres, a los 11,5 ± 0,7 APVC. Se generaron ecuaciones para estimar la MG para hombres y mujeres, utilizando como predictores la edad cronológica, APVC y circunferencia de cintura. Se desarrollaron percentiles para evaluar la MG por absorciometría de rayos X de doble energía y por ecuaciones de regresión. Conclusión. Las ecuaciones mostraron aceptabilidad para determinar la MG; además, se han propuesto valores referenciales para evaluar la MG en función de la edad cronológica y biológica.

Introduction. The assessment of body composition is relevant to establish nutritional status and identify potential health risks. Objective. a) To develop regression equations to predict fat mass (FM) using a dual-energy X-ray absorptiometry as reference method; b) to propose reference FM values based on chronological and biological age for Chilean children and adolescents. Methodology. Cross-sectional study in children and adolescents aged 5.0 to 18.9 years from the Maule Region (Chile). The sample was made up of 3593 subjects in a probabilistic fashion (stratified). Subjects' weight, standing height, sitting height, and waist circumference were assessed. Body mass index and age at peak development velocity (APGV) were estimated. Body composition (FM, fat-free mass, bone mass, and fat percentage) were established based on a dual-energy X-ray absorptiometry scan. Results. APGV (biological age) was 14.9 ± 0.9 years among boys and 11.5 ± 0.7 among girls. Equations were developed to estimate FM among boys and girls using chronological age, APGV, and waist circumference as predictors. Percentiles were estimated to assess FM by dual-energy X-ray absorptiometry and regression equations. Conclusion. Equations were acceptable to establish FM; in addition, reference values were proposed to assess FM based on chronological and biological age.