Comparison of anthropometric indicators as predictors of the percentage of fat mass in young people and older adults in Chile.

OBJECTIVE: To verify whether triponderal mass index (TMI) has a greater accuracy than body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR) as predictors of obesity in young people and older adults in a region of Chile. MATERIAL AND METHODS: A cross-sectional descriptive study was carried out in 1176 adults (565 men and 611 women) from the Maule region (Chile). Their ages ranged from 20 to 80 years. The percentage of fat mass (%FM) was evaluated by means of dual energy X-ray absorptiometry (DXA). Weight, height and waist circumference (WC) were evaluated. TMI, BMI and WHtR were calculated. RESULTS: The %FM predictions for BMI were 0.47% for men and 0.50% for women; for TMI, it was 0.50% for men and 0.51% for women; for WC, it was 0.28% for men and 0.21% for women; and finally, for WHtR, it was 0.28% in men and 0.21% in women. The area under the curve (AUC) for BMI was 0.85 in men and 0.85 in women; for TMI, it was 0.87 in men and 0.86 in women; for WHtR, it was 0.76 in men and 0.72 in women; and for WC, the AUC was 0.72 in men and 0.71 in women. CONCLUSION: It was shown that TMI is the indicator that presented the greatest association with %FM and estimates body fat levels with greater precision than BMI, WC and WHtR. The results suggest its use and application as an indicator that discriminates obesity in young, middle-aged and elderly adults.

Relationship between age and handgrip strength: Proposal of reference values from infancy to senescence.

Introduction: Measurement of hand grip strength (HGS) has been proposed as a key component of frailty and has also been suggested as a central biomarker of healthy aging and a powerful predictor of future morbidity and mortality. Objectives: (a) To determine whether a nonlinear relationship model could improve the prediction of handgrip strength (HGS) compared to the linear model and (b) to propose percentiles to evaluate HGS according to age and sex for a regional population of Chile from infancy to senescence. Methods: A cross-sectional descriptive study was developed in a representative sample of the Maule region (Chile). The volunteers amounted to 5,376 participants (2,840 men and 2,536 women), with an age range from 6 to 80 years old. Weight, height, HGS (right and left hand) according to age and sex were evaluated. Percentiles were calculated using the LMS method [(L (Lambda; asymmetry), M (Mu; median), and S (Sigma; coefficient of variation)]. Results and discussion: There were no differences in HGS from 6 to 11 years of age in both sexes; however, from 12 years of age onwards, males presented higher HGS values in both hands (p < 0.05). The linear regression between age with HGS showed values of R 2 = 0.07 in males and R 2 = 0.02 in females. While in the non-linear model (cubic), the values were: R 2 = 0.50 to 0.51 in men and R 2 = 0.26 in women. The percentiles constructed by age and sex were: P5, P15, P50, P85, and P95 by age range and sex. This study demonstrated that there is a nonlinear relationship between chronological age with HGS from infancy to senescence. Furthermore, the proposed percentiles can serve as a guide to assess and monitor upper extremity muscle strength levels at all stages of life.

Comparison of anthropometric indicators as predictors of the percentage of fat mass in young people and older adults in Chile. / Comparación de indicadores antropométricos como predictores del porcentaje de masa grasa en jóvenes y adultos mayores de Chile.

OBJECTIVE: To verify whether tri-ponderal mass index (TMI) has a higher accuracy than body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR) as predictors of obesity in young people and older adults in a region of Chile. MATERIAL AND METHODS: A cross-sectional descriptive study was carried out in 1,176 adult subjects (565 men and 611 women) from the Maule region (Chile). The age range was from 20 to 80 years old. The percentage of fat mass (%FM) was evaluated by means of dual energy X-ray absorptiometry (DXA). Weight, height and WC were evaluated. TMI, BMI and WHtR were calculated. RESULTS: The predictions of %FM for BMI were 0.47% for men and 0.50% for women, for TMI it was 0.50% for men and 0.51% for women, for WC it was 0.28% for men and 0.21% for women, and finally, for the WHtR it was 0.28% in men and 0.21% in women. The area under the curve (AUC) for the BMI was 0.85 in both men and women, for the TMI, it was 0.87 in men and 0.86 in women, for the WHtR, in men it was 0.76 and in women it was 0.72, and for WC, the AUC in men was 0.72 and in women it was 0.71. CONCLUSION: It was shown that TMI is the indicator that presented the greatest association with %FM and estimates body fat levels with greater precision than BMI, WC and WHtR. The results suggest its use and application as an indicator that discriminates obesity in young, middle and late-aged adults.

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 .

Relationship between muscular fitness and bone health in young baseball players.

The physical actions developed by baseball players can increase muscular fitness, and consequently improve bone health. The objective was to relate some indicators of muscular fitness to bone health in young baseball players. A descriptive cross-sectional study was carried out in 102 children and adolescent baseball players of the Brazilian National Team. The age range ranged from 9.0 to 15.0 years, the average chronological age was 12.2±2.2 years and the maturity status was 14.8±0.5 APHV (age at peak height velocity). Anthropometry, body composition [% fat, fat mass (FM) and fat-free mass (FFM)], physical tests [horizontal jump (HJ) and medicine ball throw (MBT)] bone health was estimated by anthropometry [bone mineral density (BMD) and bone mineral content (BMC)]. There was positive and significant correlation between bone health with FFM (r2= 89%) and with muscle strength tests (HJ and MBT) (R2= 55 to 75%). Young baseball players classified with low bone health level, reflected decreased values of FFM, HJ and MBT, in relation to young players classified with moderate and high bone health level (p<0.05). It was shown that good bone health is a consequence of a greater presence of muscular fitness, as a result of increased physical activity. These results suggest that emphasis should be placed on those young people who present a greater risk of having low BMD and BMC.

Crecimiento físico y composición corporal de jóvenes beisbolistas brasileros por edad cronológica y estado de madurez / Physical growth and body composition of young Brazilian baseball players by chronological age and maturity stage

Introducción: El crecimiento físico (CF), maduración biológica (MB) y la composición corporal (CC) son indicadores de salud que deben ser controlados para detectar anomalías individuales y para la selección y detección de talentos deportivos. El objetivo fue verificar si los parámetros de CF y la CC de jóvenes beisbolistas deben ser analizados por estado de madurez antes que por edad cronológica como lo sugieren las investigaciones. Métodos: Se efectuó un estudio descriptivo transversal en102 niños y adolescentes Beisbolistas de 9.0 a 15.0 años. La selección de la muestra fue no probabilística (conveniencia). Se evaluó el peso, la estatura de pie, estatura sentada, pliegues tricipital, subscapular. Se calculó el estado de madurez por la técnica antropométrica de Mirwald. El porcentaje de grasa (%G), masa grasa (MG) y masa libre de grasa (MLG) fueron estimados por ecuaciones de regresión. Resultados: El promedio de edad cronológica fue de 12,2±2,2 años, el estado de madurez fue alcanzado a los 14,8±0,5APVC y los años de experiencia en la modalidad deportiva fue de 5,6±2,2 años. Se determinaron 5 niveles de estado de madurez: -4APVC, -3APVC, -2APVC, -1APVC Y 0APVC. Los niños clasificados como púberes reflejaron valores superiores de peso, estatura, MG y MLG en comparación con los pre púberes (p<0,05).Conclusión: El estudio demostró que la evaluación del estado de madurez en jóvenes beisbolistas por medio de una técnica antropométrica no-invasiva es esencial para disminuirlos factores de confusión ocasionados por la edad cronológica, principalmente cuando se estudia el CF y la CC durante la adolescencia. (AU)

Introduction: Physical growth (FC), biological maturation (BM) and body composition (BC) are health indicators that should be monitored to detect individual abnormalities and for the selection and detection of sports talent. The objective was to verify whether the parameters of FC and CC of young baseball players should be analyzed by maturity status rather than by chronological age as suggested by research. Methods: A descriptive cross-sectional study was carried out in 102 children and adolescent baseball players aged 9.0 to 15.0 years. The sample selection was non-probabilistic (convenience). Weight, standing height, sitting height, tricipital and subscapular folds were evaluated. Maturity status was calculated by the Mirwald anthropometric technique. Fat percentage (%G), fat mass (FM) and fat-free mass (FFM) were estimated by regression equations. Results: The average chronological age was 12.2±2.2 years, the maturity stage was reached at 14.8±0.5APVC and the years of experience in the sport modality was 5.6±2.2 years. Five levels of maturity status were determined: -4APVC, -3APVC, -2APVC, -1APVC and 0APVC. Children classified as pubertal reflected higher values of weight, height, MG and GLM compared to pre-pubertal (p<0.05). Conclusion: The study demonstrated that the evaluation of maturity status in young baseball players by means of a non-invasive anthropometric technique is essential to reduce the confounding factors caused by chronological age, mainly when CF and CC are studied during adolescence. (AU)

Masa libre de grasa a partir de variables antropométricas en jugadores de voleibol masculino / Fat-free mass from anthropometric variables in men's volleyball players

INTRODUCCIÓN: La estimación de la masa muscular total es un importante componente que se relaciona con el rendimiento y con el control del entrenamiento en diversas modalidades deportivas. El objetivo del estudio fue proponer ecuaciones de regresión para estimar la masa libre de grasa a partir de variables antropométricas en jugadores de voleibol masculino y verificar la capacidad de reproducibilidad de las ecuaciones. MÉTODOS: Se efectuó un estudio descriptivo de corte transversal en 29 voleibolistas de un Club profesional de Brasil. El rango de edad oscila entre los 16.0 a 20.9 años. Se calculó el Índice de Masa Corporal. La Masa libre de grasa fue determinada por medio del escaneo de la absorciometría de rayos X de doble energía. RESULTADOS: Se generaron tres ecuaciones, cuyo poder de explicación varían entre 87 a 95%: Modelo 1: Masa libre de grasa = -10.401+0.562*Peso + 4.032*Diámetro del Tobillo (R2=0.87), Modelo 2: Masa libre de grasa = -34.806+0.330*Peso + 2.579*Circunferencia del Antebrazo (R2=0.94) y Modelo 3: Masa libre de grasa = -41.830+0.292*Peso + 2.270* Circunferencia del Antebrazo +2.638*Diámetro del Tobillo (R2=0.95). Los resultados del Índice de reproducibilidad deseable mostraron para los tres modelos predictivos valores de coeficiente de correlación de concordancia entre 0.93 a 0.95, para la Precisión entre 0.931 a 0.997 y para la exactitud entre 0.997 a 0.999. CONCLUSIÓN: Se concluye, que la Masa libre de grasa puede ser calculada con precisión y exactitud en jóvenes voleibolistas de sexo masculino a partir de variables antropométricas como el peso, diámetro del tobillo y circunferencia del antebrazo. Se sugiere el uso y la aplicación en programas de entrenamiento como un método no-invasivo y de campo

INTRODUCTION: The estimation of total muscle mass is an important component that is related to performance and training control in various sports modalities. The objective of the study was to propose regression equations to estimate fat-free mass from anthropometric variables in male volleyball players and to verify the reproducibility of the equations. METHODS: A descriptive cross-sectional study was carried out on 29 volleyball players from a professional Club in Brazil. The age range ranges from 16.0 to 20.9 years. The Body Mass Index was calculated. Fat Free Mass was determined by scanning dual energy X-ray absorptiometry. RESULTS: Three equations were generated, whose explanatory power varies between 87 to 95%: Model 1: Fat-free mass = -10.401 + 0.562 * Weight + 4.032 * Ankle Diameter (R2 = 0.87), Model 2: Weight free of Fat = -34.806 + 0.330 * Weight + 2.579 * Forearm Circumference (R2 = 0.94) and Model 3: Fat Free Mass = -41.830 + 0.292 * Weight + 2.270 * Forearm Circumference + 2.638 * Ankle Diameter (R2 = 0.95 ). The results of the Desirable reproducibility index showed, for the three predictive models, values of the correlation correlation coefficient between 0.93 to 0.95, for the Accuracy between 0.931 to 0.997 and for the accuracy between 0.997 to 0.999. CONCLUSION: It is concluded that the Fat Free Mass can be calculated with precision and accuracy in young male volleyball players from anthropometric variables such as weight, ankle diameter and forearm circumference. Use and application in training programs is suggested as a non-invasive and field method

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.

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.

Fat-Free Mass and Bone Mineral Density of Young Soccer Players: Proposal of Equations Based on Anthropometric Variables.

BACKGROUND: The assessment of body composition may assist in optimizing competitive efficiency and monitoring the success of training regimes for young soccer players. The purpose of this study was to determine the predictors for Fat-Free Mass (FFM) and Bone Mineral Density (BMD) of young soccer players. Also, the goal was to propose regression equations to estimate FFM and BDM through anthropometric variables. METHODS: One hundred and sixty-seven young soccer players ages 10.0 to 19.9 years old were studied. Weight, height, trunk-cephalic length, right arm circumference, diameter of the humerus, and length of the foot were assessed. FFM and BDM were determined by using dual X-ray absorptiometry (DXA). Maturity status using Peak Height Velocity (PHV) was calculated. RESULTS: Maturity status, weight, and circumference of the relaxed arm positively related to the FFM (R 2 = 41-66%). Similarly, PHV, weight, diameter of the humerus, and length of the foot explained BDM in both groups of soccer players (goalkeepers and filed players) (R 2 = 45-82%). Six equations to predict FFM (R 2 = 62-69%) and six to predict BDM (R 2 = 69-90%) were created. Chronological age had a limited use for predicting FFM and BDM. CONCLUSION: Results suggested the use and application of the regression equations as a non-invasive alternative for everyday use in soccer clubs.

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.

Tracking of physical fitness in elementary school children: The role of changes in body fat.

OBJECTIVES: The aim of the present study was to examine the stability of physical fitness, and the interrelationships among intra-individual changes in fitness and fatness among elementary school children. METHODS: A longitudinal study was conducted among 372 adolescents (196 boys) and followed up over 3 years (from childhood to adolescence). Physical fitness was estimated using three indicators: cardiorespiratory fitness (through a 9-minute running test), flexibility (through a sit-and-reach test), and muscle resistance (through maximal abdominals in 1 minute). Body adiposity was obtained through triceps and subscapular skinfolds. Somatic maturation was assessed by the peak of height velocity. Kappa and Lin's tests of concordance as well as logistic regression analyses were conducted with P < 0.05 in STATA 15.1. RESULTS: Tracking of physical fitness from childhood to adolescence was moderate for both sexes [boys: kappa = 0.441 (P < 0.001); LCCC = 0.591 (P < 0.001). Girls: kappa = 0.335 (P < 0.001); LCCC = 0.534 (P < 0.001)]. A larger increment in body fat was associated with a higher likelihood to decrease a tertile in physical fitness among boys [OR: 4.17 (95% CI: 1.31-13.22)] and with a lower likelihood to increase a tertile in physical fitness among both sexes [boys: OR = 0.25 (95% CI: 0.09-0.67); girls: OR: 0.37 (95% CI: 0.15-0.92)]. CONCLUSIONS: Health-related physical fitness has moderate tracking from childhood to adolescence. Increases in body adiposity from childhood to adolescence are associated with a reduction in physical fitness tertile.

Body mass index and physical fitness in Brazilian adolescents.

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 20m 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.

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.

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.

Hand grip strength and maximum peak expiratory flow: determinants of bone mineral density of adolescent students.

BACKGROUND: Maintaining and building healthy bones during the lifetime requires a complicated interaction between a number of physiological and lifestyle factors. Our goal of this study was to analyze the association between hand grip strength and the maximum peak expiratory flow with bone mineral density and content in adolescent students. METHODS: The research team studied 1427 adolescent students of both sexes (750 males and 677 females) between the ages of 11.0 and 18.9 years in the Maule Region of Talca (Chile). Weight, standing height, sitting height, hand grip strength (HGS), and maximum peak expiratory flow (PEF) were measured. Furthermore, bone mineral density (BMD) and total body bone mineral content (BMC) were determined by using the Dual-Energy X-Ray Absorptiometry (DXA). Hand grip strength and PEF were categorized in tertiles (lowest, middle, and highest). Linear regression was performed in steps to analyze the relationship between the variables. Differences between categories were determined through ANOVA. RESULTS: In males, the hand grip strength explained 18-19% of the BMD and 20-23% of the BMC. For the females, the percentage of variation occurred between 12 and 13% of the BMD and 17-18% of the BMC. The variation of PEF for the males was observed as 33% of the BMD and 36% of the BMC. For the females, both the BMD and BMC showed a variation of 19%. The HGS and PEF were divided into three categories (lowest, middle, and highest). In both cases, significant differences occurred in bone density health between the three categories. CONCLUSIONS: In conclusion, the HGS and the PEF related positively to the bone density health of both sexes of adolescent students. The adolescents with poor values for hand grip strength and expiratory flow showed reduced values of BMD and BMC for the total body. Furthermore, the PEF had a greater influence on bone density health with respect to the HGS of the adolescents of both sexes.

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.