Muscle strength and body fat percentage in children and adolescents from the Maule region, Chile

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 FMinfo:eu-repo/semantics/publishedVersio

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 researchers7sem informaçãosem informaçãoThis work was supported by the National Commission of Science and Technology, CONICYT, Chile under Grant [number 1141295], and MEC Project 8018003

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

Modelo hibrido de árbol de decisión difusa con optimización por enjambre de partículas para clasificación de Obesidad Escolar

TesisLa incorporacion de inteligencia computacional en los diagnosticos en el campo de la salud es una tendencia nueva y con un gran número de aplicaciones médicas. Muchos de los procedimientos de diagnosticos médicos se pueden categorizar como tareas de clasicación de datos inteligentes (Fan et al., 2011). En este contexto se propone en esta investigacion un modelo híbrido que integra un arbol de decisión, lógica difusa, la optimización por enjambre de partículas (PSO, por sus siglas en ingles). Utilizando para ello el análisis de regresion paso a paso (SRA, por sus siglas en ingl es) para el preprocesamiento de los datos y determine el conjunto de variables independientes que mas cercanamente afecten a la variable dependiente (obesidad). Luego se utiliza un arbol de decisión difusa para la generación de las reglas optimizado con un enjambre de partículas para mejorar los resultados de la clasi caci on de obesidad escolar, se realiza la interpretabilidad y se compara los algoritmos multiobjetivos representativos con PSO para mostrar de interpretabilidad y precision.Los resultados muestran que el modelo propuesto por medio de un arbol de decisión difusa ofrece una forma comprensible del an alisis para problemas orientados a la clasi caci on con un grado de exactitud aceptable, en ese contexto, basado a los resultados obtenidos se obtuvo las reglas de decision que mostro como exactitud en la obesidad del sexo masculino 84 %, mientras que en el sexo femenino la exactitud fue 89 %. La ambigüedad obtenida de las reglas aprendidas en el sexo masculino fue 0.04 y en escolares del sexo femenino fue ligeramente inferior (0.01). La optimizaci on por medio del algoritmo PSO mostro despues de 500 iteraciones un error RMSE de 12.04 para escolares masculinos y de 11.20 para escolares femeninos. Se concluye que de acuerdo a los resultados calculados es posible aplicar el modelo propuesto para la clasi cacion de obesidad de un modo aceptable. Adem as, se valido el uso de algoritmos multiobjetivos MOPSO utilizando un conjunto de funciones de evaluación ZDT, WFD y DTLZ que demostraron que se obtienen mejores resultados

Supervised Machine Learning Techniques for the Prediction of the State of Charge of Batteries in Photovoltaic Systems in the Mining Sector

One of the critical aspects in the mining sector is energy, being of great importance for the operation since if it were to stop, one of the consequences would be the loss of large amounts of money. The research objective is to predict the State of Charge of Batteries of equipment powered by photovoltaic solar panels in the mining sector based on automatic supervised learning techniques. A monitoring system records each energy variable programmed in the photovoltaic system, for which an analysis of the data extracted from the monitoring system was carried out. The data were evaluated using automatic supervised learning techniques using the RapidMiner tool, whose prediction average was 90.12%. The technique of automatic supervised learning of artificial neural networks was chosen to predict the state of charge of batteries for photovoltaic systems. A software tool was built with the neural network. The analysis and discussion of the results of the training of the model were carried out, the contribution of this research being to determine the prediction of the state of charge of batteries in photovoltaic systems in the mining sector using techniques of supervised machine learning which was the neural network. Finally, with the model correctly trained, validation was carried out that allowed comparing the predictive data with the data in real-time, obtaining a good relationship and satisfactory results

Assessment of self-perception of physical fitness and proposal for standards among Chilean adolescent students: the EAPAF study

Introduction: Physical fitness may be assessed among children and adolescents in a quantitative and qualitative manner. At present, in Chile, there are no tools available to assess self-perception of physical fitness. Therefore, the purpose of this study was to develop a valid and reliable instrument that would allow to assess self-perception of physical fitness among adolescents and propose standards for age and sex. Material and methods: A survey was administered among adolescent students from six public schools in the Maule Region, Chile, selected in a probabilistic (stratified) fashion. To measure self-perception of physical fitness, a qualitative instrument was developed: the Self-Perception of Physical Fitness Scale (EAPAF, escala de autopercepcion de la aptitud fisica), which is made up of four dimensions and 18 questions. The LMS method (L: Box-Cox coefficient, M: median curve, and S: variation coefficient) was used to establish percentiles and propose references by dimension, age and sex. Results: A total of 3060 adolescents (1702 boys and 1358 girls) aged 11.0 to 18.9 years old were included. The factor analysis evidenced four factors. Saturation values were above 0.40. The percentage of instrument explanation reached 54.24%. In terms of reliability, the 18 questions reflected that Cronbach's alpha was between 0.82 and 0.85. Percentiles (p15, p50 and p85) were developed to classify self-perception of physical fitness by dimension, age and sex. Boys showed higher scores in the self-perception of physical fitness scale when compared to girls (p < 0.001). Conclusion: The instrument developed in this study was valid and reliable. In addition, the standards proposed may become a useful tool to classify adolescents in relation to their self-perception of physical fitness1144319328sem informaçã

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

Quantification of the Number of Steps in a School Recess by Means of Smart Bands: Proposal of Referential Values for Children and Adolescents

(1) Background: Regular physical activity has multiple benefits. Therefore, school recess is a key tool to provide opportunities for schoolchildren to engage in extracurricular physical activity, have fun, play and interact with their peers. The aim is to provide reference data to quantify the number of steps that children and adolescents perform in a school recess using smart bands according to age range and sex. (2) Method: A descriptive cross-sectional study was carried out in 494 schoolchildren aged 6 to 17 years (292 males and 202 females). Weight, standing height and waist circumference (WC) were evaluated. The body mass index (BMI) was calculated. The quantification of the number of steps during school recess was performed using a smart band. (3) Results: Percentiles were constructed for the number of steps (number of steps/recess). The cut-off points considered were p75 (above average). The median values in both sexes decreased as the age range increased. Youth who walked fewer steps during recess (<p25: below average) had elevated BMI and WC values relative to those who walked within average and above average. (4) Conclusion: The number of steps taken by schoolchildren during school recess decreases drastically with advancing age. The proposed reference values can be used to categorize schoolchildren according to the number of steps taken and to compare them among their peers. The results suggest their use and application in schools as a way of achieving the minimum physical activity recommendations

Reference values for the 6-min walking test in children and adolescents living in a moderate altitude region of Peru

Abstract Background The assessment of cardiorespiratory fitness is important because it allows the identification of subgroups with poor health status and the targeting of effective intervention strategies to improve health. Objective To compare the cardiorespiratory capacity of children and adolescents living in a moderate altitude region of Peru with international studies and to develop reference values for the 6-min walk test (6MWT) according to age and sex. Methodology A descriptive cross-sectional study of schoolchildren from a region of moderate altitude in Peru was carried out. A total of 704 schoolchildren (400 males and 304 females) with an age range of 6 to 17 years were studied. Weight, standing height, waist circumference (WC), body mass index (BMI) and tri-ponderal mass index (TMI) were evaluated. The 6MWT was assessed in a straight line over a distance of 30 m. Percentiles were created through the LMS method [L (skewness: lambda), M (median: mu) and S (coefficient of variation: Mu)]. Results There were discrepancies in cardiorespiratory fitness performance with international studies by age and sex. The schoolchildren in the study reached stability and the highest number of meters in the last two age ranges (14 to 15 years: 698.1 m and 16 to 17 years 686.3 m in males). While females (14 to 15 years: 698.1 m and 16 to 17 years: 686.3 m). The proposed percentile values show ascending values as age advances. The cut-off points adopted are: low cardiorespiratory fitness  75. Conclusion We verified that the cardiorespiratory fitness evaluated by means of the 6MWT is ascending with the course of age. Even the performance with other countries is heterogeneous at early and middle ages, stabilizing during adolescence. The proposed reference values can be used to evaluate and monitor cardiorespiratory fitness during physical education classes