Physical activity habits and their relationship with sociodemographic factors in Chilean adolescents.

Physical activity plays an important role in the well-being and development of adolescents. Physical activity habits expressed in terms of frequency and duration are consistently associated with sociodemographic factors such as age, gender, and socioeconomic status. However, there is less evidence of the relationship between the type and context of physical activity in adolescents. The aim of this article is to analyze physical activity habits and their relationship with sociodemographic factors in Chilean adolescents. The cross-sectional study consisted of 7,263 adolescents aged between 10 and 20 years old, students from both public and private schools in all regions of Chile. Physical activity habits were examined by means of a self-report questionnaire. The age groups were classified according to the three stages of adolescence (early: 10 to 13, middle: 14 to 16, and late: 17 to 20 years old). Socioeconomic level was established based on the school vulnerability index (SVI) of the school attended by each adolescent. In the study it was obvious to the level of physical activity for the adolescents was below the international recommendations. A statistically significant association can also be found between the sociodemographic factors studied and the physical activity habits reported by the young people. The multivariate regression analysis established that the risk of not achieving the physical activity recommendations was 2.8 times higher in females than in males, 2.4 times higher in the older age groups (14-16 and 17-20 years old) compared to the 10-13-year age range and 1.1 times in the medium and high vulnerability groups than in the low socioeconomic vulnerability group. These findings highlight the importance of considering all these factors holistically whenever designing programs or public policies that promote the development of healthy physical activity habits in adolescents.

Muscle Mass in Children and Adolescents: Proposed Equations and Reference Values for Assessment.

Objectives: The goal of this study was to develop regression equations to estimate LM with anthropometric variables and to propose percentiles for evaluating by age and sex. Methods: A cross sectional study was conducted with 2,182 Chilean students (1,347 males and 835 females). Ages ranged from 5.0 to 17.9 years old. A total body scan was carried out with the double energy X-ray anthropometry (DXA) to examine and measure lean muscle mass of the entire body. Weight, height, and the circumference of the relaxed right arm were also measured. Results: Four anthropometric equations were generated to predict lean mass for both sexes (R 2 = 83-88%, SEE = 3.7-5.0%, precision = 0.90-0.93, and accuracy = 0.99). The Lambda-mu-sigma method was used to obtain the sex-specific and age-specific percentile curves of lean mass (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95, and p97). Conclusion: The four proposed equations were acceptable in terms of precision and accuracy to estimate lean mass in children and adolescents. The percentiles were created by means of anthropometric equations and real values for DXA. These are fundamental tools for monitoring LM in Chilean children and adolescents of both sexes.

Physical Growth and Body Adiposity Curves in Students of the Maule Region (Chile).

Objectives: Physical growth and body adiposity patterns provide relevant information to infer the nutritional and health status of students. Our objectives were (a) to compare the variables of body adiposity and physical growth of Chilean children and adolescents with data from the CDC-2012 and international studies, and (b) to develop regional reference curves to evaluate growth and body adiposity. Methods: 8,261 children and adolescents were studied. We evaluated the weight, height, and waist circumference (WC). The Body Mass Index (BMI) was calculated. Their physical growth and body adiposity were compared with the CDC-2012 references as well as with other international references. Percentile curves for weight, height, BMI, and WC were constructed with the LMS method. Results: The Chilean students showed reduced weight and height during adolescence when compared with the CDC-2012 reference. During early ages, the BMI for the Chilean sample was lower while at advanced ages, the WC values were greater in comparison to the CDC-2012 reference. Graphic comparisons with international studies indicated that Chilean students weighed more at all ages. However, height was slightly greater until age 14 for males and age 11 for females. Body adiposity (BMI and WC) for the Chilean students was slightly higher at early ages while at later ages, adiposity values were relatively similar for both sexes. Conclusions: Discrepancies were observed between the physical growth and body adiposity trajectories and the American CDC-2012 references and the international studies. The proposed percentiles for weight, height, BMI, and WC for each age and sex may be useful for health sciences professionals and researchers.

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.

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

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.

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.

Concordancia de ecuaciones que predicen el porcentaje de grasa en jóvenes futbolistas / Concordance of equations that predict the percentage of fat in young players

Introducción: la evaluación de la composición corporal puede ser relevante en el monitoreo de efectos potenciales de los programas de entrenamiento y salud de los jóvenes atletas. Objetivo: Analizar la concordancia de una ecuación de % de grasa corporal específica con ecuaciones genéricas que fueron desarrolladas para jóvenes no-deportistas y deportistas adultos. Métodos: Se efectuó un estudio de tipo descriptivo-comparativo. Fueron evaluados 109 jóvenes futbolistas de un club del fútbol profesional de Chile. Las edades oscilan entre 12.9 a 20.4. Se evaluó el peso, estatura de pie, estatura sentada, cinco pliegues cutáneos (bicipital, subscapular, supra-iliaca, abdominal). Se calculó la maduración somática por medio de los años de pico de velocidad de crecimiento (APVC). Se calculó el porcentaje de grasa (%G) a través de una ecuación específica para futbolistas y cinco ecuaciones generales. Resultados: La edad cronológica fue de 16.1±1.8 años y la edad biológica se presentó a los 14.8±0.9APVC. Los valores de %G oscilaron entre 8.8 a14.3% en las seis ecuaciones. El coeficiente de concordancia (CC) y los valores de precisión (P) y exactitud (Euros) entre la ecuación de Gómez-Boileau (CC= 0.34, P=0,60, E=0,42), Gómez-Slaugther (CC= 0.30, P=0,60, P=0,36, Gómez-Lohman (CC= 0.53, P=0,70, E= 0.61), Gómez-Cossio-Bolaños (CC= 0.62, P=0.80, E= 0,68), y Gómez-Faulkner (CC= 0,48, P= 0,80, E= 0,52). Conclusión: Las ecuaciones de Lohman y Cossio-Bolaños propuestas para adultos pueden ser utilizados para predecir el porcentaje de grasa corporal en jóvenes futbolistas entre 12 a 20 años, puesto que mostraron concordancia y elevados valores de precisión y exactitud en sus predicciones

Background: The evaluation of body composition may be relevant in monitoring the potential effects of the training and health programs of young athletes. Objective: To analyze the concordance of a specific body fat% equation with generic equations that were developed for non-athletes and adult athletes. Methodology: A descriptive-comparative study was carried out. 109 young footballers from a professional soccer club in Chile were evaluated. The ages range from 12.9 to 20.4. The weight, standing height, sitting height, five skin folds (bicipital, subscapular, supra-iliac, abdominal) were evaluated. Somatic maturation was calculated by means of the years of peak growth rate (APVC). The percentage of fat (% G) was calculated through a specific equation for footballers and five general equations. Results: The chronological age was 16.1 ± 1.8 years and the biological age was presented at 14.8 ± 0.9APVC. The values of% G ranged from 8.8 to 14.3% in the six equations. The concordance coefficient (CC) and the values of precision (P) and accuracy Euros between the Gómez-Boileau equation (CC = 0.34, P = 0.60, E = 0.42), Gómez-Slaugther (CC = 0.30), P = 0.60, P = 0.36, Gómez-Lohman (CC = 0.53, P = 0.70, E = 0.61), Gómez-Cossio-Bolaños (CC = 0.62, P = 0.80, E = 0, 68), and Gómez-Faulkner (CC = 0.48, P = 0.80, E = 0.52). Conclusion: The Lohman and Cossio-Bolaños equations proposed for adults can be used to predict the percentage of body fat in young players between 12 to 20 years, since they showed concordance and high values of precision and accuracy in their predictions

Predictores de adiposidad corporal en jóvenes con síndrome de Down / Predictors of body adiposity in young people with Down syndrome

Fundamentos: Analizar los pliegues cutáneos que mejor predicen los indicadores de adiposidad corporal en jóvenes síndrome de Down (SD). Métodos: Se diseñó un estudio descriptivo transversal (correlacional). Fueron seleccionados de forma no-probabilística por conveniencia 67 jóvenes (33 mujeres y 34 hombres) con SD de la provincia de Talca (Chile). El rango de edad oscila entre 10 y 25 años. Se evaluó el peso, estatura, circunferencia de la cintura, cadera y cinco pliegues cutáneos (bicipital, tricipital, subescapular,suprailiaco y muslo). Se calculó el índice de masa corporal (IMC) y el índice cintura-cadera (ICC). Resultados: En hombres, tanto en adolescentes, como en jóvenes adultos, la circunferencia de la cintura y cadera explicaron entre 30 a 62%, mientras que en mujeres adolescentes la circunferencia de la cadera predijo la adiposidad en un 19%, y en mujeres adultas el ICC explica el 12%. El IMC en ambos sexos y grupos (adolescentes y adultos) evidenció valores de R2 inferiores a los demás indicadores (R2=0,09 a16%). Conclusión: La circunferencia de la cadera y la cintura deben ser utilizadas para valorar la adiposidad corporal en hombres adolescentes y jóvenes adultos con SD, mientras que, en mujeres adolescentes, únicamente la circunferencia de la cadera mostró ser predictor de la adiposidad corporal y el ICC en mujeres adultas

Background: To analyze the skin folds that better predict body adiposity indicators in young Down syndrome (DS).Methods: A transversal (correlational) descriptive study was designed. 67 young people (33 women and 34 men) with DS from the province of Talca (Chile) were selected in a non-probabilistic manner for convenience. The age range varies between 10 and 25 years. The weight, height, circumference of the waist, hip and five skin folds (bicipital, tricipital, subscapular, suprailiac and thigh) were evaluated. The body mass index (BMI) and the waist-hip index (BCI) were calculated. Results: In men, both in adolescents, and in young adults, waist circumference and hip circumference explained between 30 to 62%, while in adolescent women the circumference of the hip predicted adiposity in 19%, and in adult women the ICC explains 12%. The BMI in both sexes and groups (adolescents and adults) showed R2 values lower than the other indicators (R2 = 0.09 to 16%). Conclusion: Hip circumference and waist circumference should be used to assess body adiposity in adolescent males and young adults with DS, while in adolescent females, only hip circumference showed to be a predictor of bodily adiposity and the ICC in adult women

Normative data for handgrip strength in children and adolescents in the Maule Region, Chile: Evaluation based on chronological and biological age.

BACKGROUND: Hand grip strength (HGS) is associated with a number of causes resulting in cardiovascular death, in addition to bone fragility, and the presence of sarcopenia. The goal of our study was to analyze HGS of students based on chronological and biological age and propose normative standards for children and adolescents from Chile. METHODS: We studied 4604 school children of both sexes between the ages of 6.0 and 17.9 years of age. Weight, standing height, sitting height, and hand grip strength (HGS- right and left) were measured. The Body Mass Index (BMI) was calculated, and the biological age was calculated by using age at peak height velocity (APHV). RESULTS: When arranged by chronological age, no significant differences occurred in HGS between both sexes of school children from age 6 to 12 years of age. However, from ages 13 to 17, males showed greater HGS than females. Significant differences also emerged between both sexes and at all levels for biological age (APHV). For males, chronological age explained the HGS occurring between 0.74 to 0.75% and for females between 0.54 to 0.59%. For males, biological age explained the HGS for the range of 0.79 to 0.80% and 0.62 to 0.67% for females. The normative data for HGS for both sexes is expressed in percentiles. CONCLUSIONS: HGS during childhood and adolescence needs be analyzed and interpreted in terms of biological age rather than chronological age. The normative data to evaluate the HGS are a tool that can help professionals working in clinical and epidemiological contexts.

Reference norms for evaluating maximum expiratory flow of children and adolescents of the Maule Region in Chile.

BACKGROUND: The norms for evaluating the maximum expiratory flow (MEF) usually are developed according to chronological age and height. However, to date, little research has been conducted using reference values that take into account the temporal changes of biological maturation. The objectives of this study were to (a) compare the MEF with those of other international studies, (b) align the MEF values with chronological and biological age, and (c) propose reference standards for children and adolescents. METHODS: The sample studied consisted of 3,566 students of both sexes (1,933 males and 1,633 females) ranging in age from 5.0 to 17.9 years old. Weight, standing height, and sitting height were measured. Body mass index was calculated. Biological maturation was predicted by using age of peak height velocity growth (APHV). MEF (L/min) was obtained by using a forced expiratory manoeuvre. Percentiles were calculated using the LMS method. RESULTS AND DISCUSSION: Predicted APHV was at age 14.77 ± 0.78 years for males and for females at age 12.74 ± 1.0 years. Biological age was more useful than chronological age for assessing MEF in both sexes. Based on these findings, regional percentiles were created to diagnose and monitor the risk of asthma and the general expiratory status of paediatric populations.

Validez, confiabilidad y percentiles para valorar el auto-concepto físico de jóvenes universitarios de Perú / Validity, reliability and percentiles to assess the physical self-concept of young university students in Peru

Fundamentos: Verificar la validez y confiabilidad de la escala de auto-concepto físico (ACF) y proponer referencias por medio de percentiles. Métodos: Se estudió 1.937 jóvenes universitarios (1.064 hombres y 873 mujeres) de la ciudad de Puno, Perú. Se evaluó el peso y estatura y se calculó el índice de Masa Corporal (IMC) de los universitarios. Se utilizó la técnica de la encuesta aplicando una escala de ACF de 30 preguntas. La validación se efectuó por medio de Análisis Factorial Confirmatorio (A-FC). La confiabilidad de verificó por medio de Alpha de Cronbach. Se generaron percentiles por medio del método LMS. Resultados: El A-FC arrojó saturaciones superiores a 0,41 para 29 preguntas. En el modelo generado con 29 preguntas, el porcentaje de explicación de la varianza fue del 42%, el KMO fue de 0,911 (X2= 15578.883, gl= 435, p<0,001). El alpha de Cronbach mostró valores superiores a 0,75. Los percentiles propuestos permiten categorizar el ACF en tres niveles: p85 (alto ACF).Conclusiones: La escala de ACF es válida y confiable para jóvenes universitarios. Los percentiles son una alternativa para identificar, clasificar y categorizar los niveles de ACF

Background: To verify the validity and reliability of the physical self-concept scale (CFA) and to propose references by means of percentiles. Methods: 1937 university students(1064 men and 873 women) from the city of Puno, Peru, were studied. The weight and height were evaluated and the Body Mass Index (BMI) was calculated. The survey technique was used applying an ACF scale of 30 questions. Validation was carried out through Confirmatory Factor Analysis (CF-A). The reliability of verified by means of Alpha de Cronbach. Percentiles were generated by means of the LMS method. Results: The CF-A showed saturations higher than 0.41 for 29 questions. In the model generated with 29 questions, the percentage explanation of the variance was 42%, the KMO was 0.911 (X2 = 15578.883, gl = 435, p <0.001). Cronbach's alpha showed values above 0.75. The proposed percentiles allow categorizing the ACF into three levels: p85 (high ACF). Conclusions: The ACF scale is valid and reliable for university students. The percentiles are an alternative to identify, classify and categorize the ACF levels

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.

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

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.

Validación de ecuaciones y propuesta de valores referenciales para estimar la masa grasa de jóvenes universitarios chilenos / Validation of equations and proposed reference values to estimate fat mass in Chilean university students

Objetivos: a)Proponer ecuaciones basadas en índices antropométricos para estimar la masa grasa (MG) utilizando como método de referencia la absorciometría de rayosX de doble energía (DXA), y b)establecer normas de referencia para valorar la MG estimada. Material y métodos: Estudio transversal en 6.713 jóvenes universitarios (3.354 hombres y 3.359 mujeres) de Chile con un rango de edad comprendido entre los 17,0 y los 27,0años. Se obtuvieron medidas antropométricas (peso, talla y perímetro cintura) en todos los participantes. Se realizó una DXA en 683 participantes. Un total de 478 sujetos fueron seleccionados para desarrollar ecuaciones de regresión y 205 para su validación cruzada. Los percentiles se desarrollaron con los datos de 6.030 participantes. Para generar las ecuaciones se utilizó el análisis de regresión múltiple por pasos. Para desarrollar los percentiles se utilizó el método LMS. Resultados: Las ecuaciones para hombre fueron: 1)MG=−35.997,486 +232,285 *Peso +432,216 *CC (R2=0,73, EEE=4,1); 2)MG=−37.671,303 +309,539 *Peso +66.028,109 *ICE (R2=0,76, EEE=3.8), y para mujeres fueron: 3)MG=−13.216,917 +461,302 *Peso +91,898 *CC (R2=0,70, EEE=4,6), y 4)MG=−14.144,220 +464,061 *Peso +16.189,297 *ICE (R2=0,70, EEE=4,6). Los percentiles propuestos son: p10, p50, p85 y p95. Conclusión: Las ecuaciones desarrolladas proporcionan predicciones válidas y exactas para estimar la MG de jóvenes universitarios de ambos sexos. Los valores obtenidos mediante la aplicación de estas ecuaciones pueden ser analizados a partir de percentiles que permiten categorizar los niveles de adiposidad corporal por rango de edad y sexo (AU)

Objectives: (I) To propose regression equations based on anthropometric measures to estimate fat mass (FM) using dual energy X-ray absorptiometry (DXA) as reference method, and (II) to establish population reference standards for equation-derived FM. Material and methods: A cross-sectional study on 6,713 university students (3,354 males and 3,359 females) from Chile aged 17.0 to 27.0years. Anthropometric measures (weight, height, waist circumference) were taken in all participants. Whole body DXA was performed in 683 subjects. A total of 478 subjects were selected to develop regression equations, and 205 for their cross-validation. Data from 6,030 participants were used to develop reference standards for FM. Equations were generated using stepwise multiple regression analysis. Percentiles were developed using the LMS method. Results: Equations for men were: (i) FM=−35,997.486 +232.285 *Weight +432.216 *CC (R2=0.73, SEE=4.1); (ii)FM=−37,671.303 +309.539 *Weight +66,028.109 *ICE (R2=0.76, SEE=3.8), while equations for women were: (III) FM=−13,216.917 +461,302 *Weight+91.898 *CC (R2=0.70, SEE=4.6), and (IV) FM=−14,144.220 +464.061 *Weight +16,189.297 *ICE (R2=0.70, SEE=4.6). Percentiles proposed included p10, p50, p85, and p95. Conclusion: The developed equations provide valid and accurate estimation of FM in both sexes. The values obtained using the equations may be analyzed from percentiles that allow for categorizing body fat levels by age and sex (AU)

Validation of equations and proposed reference values to estimate fat mass in Chilean university students. / Validación de ecuaciones y propuesta de valores referenciales para estimar la masa grasa de jóvenes universitarios chilenos.

OBJECTIVES: (i) To propose regression equations based on anthropometric measures to estimate fat mass (FM) using dual energy X-ray absorptiometry (DXA) as reference method, and (ii)to establish population reference standards for equation-derived FM. MATERIAL AND METHODS: A cross-sectional study on 6,713 university students (3,354 males and 3,359 females) from Chile aged 17.0 to 27.0years. Anthropometric measures (weight, height, waist circumference) were taken in all participants. Whole body DXA was performed in 683 subjects. A total of 478 subjects were selected to develop regression equations, and 205 for their cross-validation. Data from 6,030 participants were used to develop reference standards for FM. Equations were generated using stepwise multiple regression analysis. Percentiles were developed using the LMS method. RESULTS: Equations for men were: (i) FM=-35,997.486 +232.285 *Weight +432.216 *CC (R2=0.73, SEE=4.1); (ii)FM=-37,671.303 +309.539 *Weight +66,028.109 *ICE (R2=0.76, SEE=3.8), while equations for women were: (iii)FM=-13,216.917 +461,302 *Weight+91.898 *CC (R2=0.70, SEE=4.6), and (iv) FM=-14,144.220 +464.061 *Weight +16,189.297 *ICE (R2=0.70, SEE=4.6). Percentiles proposed included p10, p50, p85, and p95. CONCLUSION: The developed equations provide valid and accurate estimation of FM in both sexes. The values obtained using the equations may be analyzed from percentiles that allow for categorizing body fat levels by age and sex.

Auto-percepción de la aptitud física e Índice de Masa Corporal en adolescentes escolares / Self-perception of physical fitness and Body Mass Index in school adolescents

Introducción: La aptitud física junto al índice de Masa Corporal (IMC), resultan necesarios para la toma de decisiones referentes a la salud, permitiendo la implementación de programas de actividad física en la escuela. Objetivo: a) Relacionar el IMC con la auto-percepción de la aptitud física y b) verificar las diferencias de la auto-percepción de aptitud física de adolescentes con y sin exceso de peso corporal. Métodos: Se efectuó un estudio de tipo descriptivo (correlacional-comparativo). Fueron seleccionados de forma no-probabilística (accidental) 306 adolescentes (123 hombres y 183 mujeres) con un rango de edad entre 14,0 a 18,9 años. Se evaluó el peso y estatura. Se calculó el Índice de Masa Corporal (IMC). Se aplicó una escala para medir auto-percepción de la Aptitud Física. Resultados: El IMC se relacionó negativamente con la auto-percepción de la aptitud física de adolescentes de ambos sexos. En los hombres la relación fue de R2= -0,283 y en mujeres de R2= -0,145. En las comparaciones en relación a las dimensiones de la aptitud física entre adolescentes con y sin exceso de peso, se observó diferencias significativas en ambos sexos (p<0,05). Conclusión: Se determinó que un elevado IMC afecta negativamente la auto-percepción de las dimensiones de la aptitud física de adolescentes de ambos sexos. Estos resultados sugieren que la percepción de la dimensión morfológica, muscular, motora y cardiovascular debe ser estimulada y trabajada en los centros escolares para promover actividades físicas, especialmente en adolescentes con exceso de peso

Background: Physical fitness along with the Body Mass Index (BMI), are necessary for making decisions regarding health, allowing the implementation of physical activity programs in the school. Aim: a) To relate BMI to self-perception of physical fitness and b) to verify the differences in the self-perception of physical fitness of adolescents with and without excess body weight. Methods: A descriptive (correlational-comparative) study was carried out. 306 adolescents (123 males and 183 females) were selected in a non-probabilistic (accidental) form with a age range between 14.0 and 18.9 years. Weight and height were evaluated. The Body Mass Index (BMI) was calculated. A scale was used to measure self-perception of Physical Fitness. Results: BMI was negatively related to the self-perception of physical fitness of adolescents of both sexes. In men, the ratio was R2 = -0.283 and in R2 = -0.145. In the comparisons related to the physical fitness dimensions between adolescents with and without excess weight, significant differences were observed in both sexes (p <0.05). Conclusion: It was determined that a high BMI adversely affects the self-perception of the physical fitness dimensions of adolescents of both sexes. These results suggest that the perception of the morphological, muscular, motor and cardiovascular dimension should be stimulated and worked in schools to promote physical activities, especially in adolescents with excess weight

Reference standards to assess physical fitness of children and adolescents of Brazil: an approach to the students of the Lake Itaipú region-Brazil.

BACKGROUND: The importance of assessing body fat variables and physical fitness tests plays an important role in monitoring the level of activity and physical fitness of the general population. The objective of this study was to develop reference norms to evaluate the physical fitness aptitudes of children and adolescents based on age and sex from the lake region of Itaipú, Brazil. METHODS: A descriptive cross-sectional study was carried out with 5,962 students (2,938 males and 3,024 females) with an age range of 6.0 and 17.9 years. Weight (kg), height (cm), and triceps (mm), and sub-scapular skinfolds (mm) were measured. Body Mass Index (BMI kg/m2) was calculated. To evaluate the four physical fitness aptitude dimensions (morphological, muscular strength, flexibility, and cardio-respiratory), the following physical education tests were given to the students: sit-and-reach (cm), push-ups (rep), standing long jump (cm), and 20-m shuttle run (m). RESULTS AND DISCUSSION: Females showed greater flexibility in the sit-and-reach test and greater body fat than the males. No differences were found in BMI. Percentiles were created for the four components for the physical fitness aptitudes, BMI, and skinfolds by using the LMS method based on age and sex. The proposed reference values may be used for detecting talents and promoting health in children and adolescents.