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

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 < p25, moderate p25 to p75 and high cardiorespiratory fitness p > 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.

Relationship between the body mass index and the ponderal index with physical fitness in adolescent students.

BACKGROUND: The relationship between the Body Mass Index (BMI) with physical fitness in children and adolescent populations from diverse regions are consistent. However, the relationship between the Ponderal Index (PI) with physical fitness, based on what is known to date, has not been examined in depth. The objective was to evaluate the relationships between BMI and PI with three physical fitness tests of students living at moderate altitudes in Peru. METHODS: A descriptive correlational study was carried out with 385 adolescents, between the ages of 10.0 to 15.9 years old, from the province of Arequipa, Peru. Weight, height, and three physical fitness tests (horizontal jump, agility, and abdominal muscle resistance) were evaluated. BMI and PI were calculated, and they were, then, categorized into three strata (low, normal, and excessive weight). Specific regressions were calculated for sex, using a non-lineal quadratic model for each item adjusted for BMI and PI. RESULTS: The relationship between BMI and PI with the physical tests reflected parabolic curves that varied in both sexes. The regression values for BMI in males oscillated between R2 = 0.029 and 0.073 and for females between R2 = 0.008 and 0.091. For PI, for males, it varied from R2 = 0.044 to 0.82 and for females, from R2 = 0.011 to 0.103. No differences occurred between the three nutritional categories for BMI as well as for PI for both sexes (p range between 0.18 to 0.38), as well as for low weight (BMI vs PI), normal weight (BMI vs PI), and excessive weight (BMI vs PI) (p range between 0.35 to 0.64). CONCLUSIONS: BMI showed inferior quadratic regressions with respect to the PI. In addition, physical performance was slightly unfavorable when it was analyzed by BMI. PI could be a useful tool for analyzing and predicting physical fitness for adolescents living at a moderate altitude since it corrects for the notable differences for weight between adolescents.

Establishing percentiles for blood pressure based on absolute height for children and adolescents.

BACKGROUND: Evaluating blood pressure (BP) is one element for diagnosing and preventing disease in student populations. The objectives of this research were to (a) identify the range of height for measuring BP adjusted for student populations and (b) propose percentiles for evaluating BP based on height. METHODS: A cross-sectional study was carried out with 3,013 students. Weight, height, and diastolic (DBP) and systolic (SBP) blood pressure were evaluated. Body Mass Index (BMI) was calculated. Height ranges of 5 and 10 cm were generated. RESULTS: R2 values for height ranges of 5 cm consisted of [normotensive: DBP (R2 = 10 to 13%) and SBP (R2 = 14 to 20%), and for hypertensive: DBP (R2 = 0.07 to 15%) and for SBP (R2 = 29 to 32%)]. For height ranges of 10 cm, values included: [normotensive: DBP (R2 = 10 to 15%), and SBP (R2 = 15 to 21%) and for hypertensive: DBP (R2 = 0.07 to 16%) and SBP (R2 = 29 to 35%)]. For 5 cm height ranges, diferences occurred between both sexes for DBP (in 5 height ranges from 123 to 148 cm and 158 to 168 cm) and for the SBP (in 6 height ranges from 128 to 148 cm and from 158 to 168 cm). In the 10 cm categories, diferences appeared in DBP (from 138 to 148 cm) and in the SBP (from 158 to 168 cm). CONCLUSIONS: Height is a determinant for evaluating blood pressure, and height ranges of 10 cm are more suitable for children and adolescents. The proposed percentiles based on height ranges allowed assessment of the DBP and SBP suggest their use in epidemiological and educational contexts.

Physical growth and body adiposity patterns in children and adolescents at high altitudes in Peru: Proposed percentiles for assessment.

OBJECTIVES: This study's purpose was to compare physical growth (PG) patterns of children and adolescents living at high elevations with those of other geographic regions, relate body adiposity indicators, and develop percentile reference tables for assessing physical growth and body adiposity. METHODS: The sample included 1536 children and adolescents ages 5.0 to 17.9 years from Puno (Peru) located between 3821 and 4349 m above sea level. Weight, height, arm and waist circumferences (WC), and three skinfolds measurements were recorded. Body mass index (BMI) and waist-height Index (WHI) were calculated. RESULTS: PG patterns for children living at a high altitude reflected similar values for weight, height, and arm circumference (AC) to those of their counterparts living in Puno (Peru) and La Paz (Bolivia). When compared with children living at moderate altitudes in Peru, they showed slightly lower PG values. BMI explained between 41% and 64% of the variance in sum of the skinfolds, while WC explained between 47% and 66%. HWI was not a strong predictor of variation in sum of skinfolds. Percentiles were generated for WC and the sum of skinfolds. CONCLUSION: Weight, height, and, arm and waist circumference patterns for children and adolescents living at high altitudes were similar to those of La Paz (Bolivia). WC and the sum of the skinfolds were better indicators for analyzing abdominal obesity compared to BMI and WHI. The percentiles proposed may be a useful tool for identifying high risk of developing overweight disorders in pediatric populations living at high altitudes.

[Development of equations based on Body Mass Index to estimate fat mass in older people]. / Validez de ecuaciones y propuesta de valores referenciales para estimar la masa grasa de adultos mayores.

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

Prediction of fat-free mass from body surface area in young basketball players.

BACKGROUND: Fat Free Mass (FFM) is an important and essential indicator in various sports populations, since greater muscle and bone mass generates greater strength, endurance and speed in athletes. OBJECTIVE: The purpose of the study was to validate Body Surface Area (BSA) as an anthropometric indicator to estimate FFM in young basketball players. METHODS: A descriptive cross-sectional study was carried out in 105 male basketball players of the Brazilian Basketball Confederation of Sao Paulo (Campinas), Brazil. The age range was 11 to 15 years. Weight and height were evaluated. BSA, body mass index (BMI) and maturity status (MS) were calculated. Total body scanning was performed by dual X-ray absorptiometry (DXA). The components were extracted: Fat mass (FM), Fat free mass (FFM), percentage of fat mass (%FM) and bone mass (BM). The data were analyzed using the correlation coefficient of concordance (CCC) in terms of precision and accuracy. RESULTS: Three regression equations were generated: equation 1 had age and body weight as predictors [FFM= -30.059+(2.926*age)+(0.625*Weight)] (R2 = 92%, precision = 0.96 and accuracy = 0.99), equation 2 used age and BSA [FFM=-45.719+(1.934*age)+(39.388*BSA)] (R2 = 94%, precision = 0.97 and accuracy = 0.99) and equation 3 was based on APHV and BSA [FFM=-15.284+(1.765*APHV)+(37.610*(BSA)] (R2 = 94%, precision = 0.96 and accuracy = 0.99). CONCLUSIONS: The results suggest the use of anthropometric equation using decimal age and BSA to estimate FFM in young basketball players. This new method developed can be used to design, evaluate and control training programs and monitor the weight status of athletes.

Functional fitness benchmark values for older adults: a systematic review.

Introduction: The use of normative values and/or standards of functional fitness in adults is relevant to overall health and well-being. The objectives of the study were: to identify the physical tests of the senior fitness test (SFT) that have been applied since its proposal and to describe the proposed percentiles according to age, sex and country. Methods: A systematic review study was conducted in the Pubmed and Scopus databases. As eligibility criteria, we considered the period from 1999 to 2022 that presented data on SFT test used in the population over 60 years of age and that described normative values through percentiles. MeSH were used as: (1) Physical fitness, Exercise test, Senior Fitness Test, Functional fitness, Cardiorespiratory fitness, (2) older adult, aged, (3) Reference standards, standards, standards of care. Boolean operators "AND" and "OR" were included. Data extracted from the selected studies included: year of publication, country, sample age, sample size, sample sex, fitness component. Results and discussion: Seven studies were identified in five countries (03 in China, 01 in Poland, 01 in Portugal, 01 in Spain and 01 in United States). The age range ranged from 60 to 103 years. The studies were conducted in both sexes. The study with the smallest sample size was by Chung et al. (China) with 944 participants and the largest number of participants was the study by Rikli and Jones in the United States with 7,183 participants. In general, no study was able to complete 100% (8 components) of the tests proposed in the SFT. Normative values were presented through percentile distribution (p10, p50 and p90) organized by age ranges. Males presented better performance in FPF tests than females in all tests. Since the first publication of the SFT until 2022, seven articles have been published in countries such as United States, China (three regional studies), Poland, Portugal and Spain. No study has published the complete battery with its eight components. The percentiles of functional fitness reflect decline with advancing age. Systematic review registration: PROSPERO (CRD42023441294: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023441294).

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 (

Bibliometric study on scientific productivity in the use of smart bracelets.

In recent years, wearable sensors and mHealth applications are becoming an important part for recording and monitoring health parameters. The aim is to characterize bibli-ometric indicators on scientific productivity in the use of smart bracelets according to scientific journal, study topic and publication trend. A bibliometric study was per-formed. The data extracted from the articles were: year of publication, name of the journal, language of publication, country, type of study and subject matter. A total of 45 studies were identified (21 cross-sectional and 24 experimental), of which 43 were published in English, one in Spanish and one in German. A total of 32 scientific journals published eight research topics related to smartwatch use [active living with 17 studies (37.8%), followed by stress and anxiety with 7 studies (15.6%), nanogenerators (batteries) with 6 studies (13.3%), computing with 5 studies (11.1%), chronic diseases 4 studies (8.9%), COVID propagation 3 studies (6.7%), energy expenditure 2 studies (4.4%) and occupational health 1 study (2.2%)]. The journal Sensors (Basel) published the most articles in the last 6 years (n=7, 16%). The scientific productivity of both study types reflects a positive trend (cross-sectional studies R2= 0.82 and in experimental studies R2= 0.76). A total of 45 cross-sectional and experimental studies using smart-watches were verified in eight different study topics. The most investigated category was active living and the journal that published the highest number of articles was the journal Sensors (Basel).

Annotated Peruvian banknote dataset for currency recognition and classification.

The real-time detection of multinational banknotes remains an ongoing research challenge within the academic community. Numerous studies have been conducted to address the need for rapid and accurate banknote recognition, counterfeit detection, and identification of damaged banknotes [1], [2], [3]. State-of-the-art techniques, such as machine learning (ML) and deep learning (DL), have supplanted traditional digital image processing methods in banknote recognition and classification. However, the success of ML or DL projects critically hinges on the size and comprehensiveness of the datasets employed. Existing datasets suffer from several limitations. Firstly, there is a notable absence of a Peruvian banknote dataset suitable for training ML or DL models. Second, the lack of annotated data with specific labels and metadata for Peruvian currency hinders the development of effective supervised learning models for banknote recognition and classification. Lastly, datasets from different regions may not align with the unique characteristics, design, and security features of Peruvian banknotes, limiting the accuracy and applicability of models in a Peruvian context [4] To address these limitations, we have meticulously curated a comprehensive dataset comprising a total of 9,315 images of Peruvian banknotes, encompassing both old and new denominations from 2011 (old) and 2019 (new) [5]. The Peruvian banknote dataset includes denominations of 10, 20, 50, and 100 Peruvian soles. Importantly, as indicated by [5], both the 2011 and 2019 families of banknotes are currently in circulation, further enhancing the dataset's relevance for real-world applications in currency recognition and verification. This dataset serves as a vital resource for addressing the challenges in real-time multinational banknote detection. By offering a comprehensive collection of images of Peruvian banknotes, both old and new, this dataset fills a critical gap in the field of banknote recognition. Researchers can utilize it to train and evaluate advanced machine learning and deep learning models, ultimately enhancing the accuracy of banknote processing systems.

Reference values for body composition and physical fitness of young Brazilian elite soccer players.

Objective: a) to verify whether body composition and physical fitness should be analyzed by chronological age and/or maturity stage in young Brazilian soccer players and b) to propose reference values for the evaluation of body composition and physical fitness by maturity stage in elite soccer players. Methods: A descriptive-correlational study was carried out in 206 young Brazilian soccer players (11-16 years old). The sample selection was non-probabilistic by convenience. Weight and standing height were evaluated. Body composition (BC) was assessed by dual X-ray absorptiometry (DXA). BC indicators [(percent fat (%F), Fat-free mass (FFM), Fat mass (FM) and Bone mass (BM)] were extracted. For physical fitness (PF), we applied the Flexibility (cm) sit and reach tests, explosive strength tests [Counter Movement Jump CMJ (cm) and horizontal jump HJ (cm)], speed [Speed 10, 20, 30 and 40 m (seconds)] and Yo-Yo endurance level I test. Percentiles were constructed for BC and PF using the LMS method [L (Lambda; skewness), M (Mu; median) and S (Sigma; coefficient of variation)]. Results: The explanatory power between chronological age (CA) with BC was: FM (R2 = 0.03%), FFM (R 2 = 0.66%) and BM (R 2 = 0.62%), while between maturity status (MS) with BC were: FM (R 2 = 0.04%), FFM (R 2 = 0.71%) and BM (R 2 = 0.66). The explanatory power between the CA with the physical fitness tests ranged from: (R 2 = 0.22-0.62%). While between MS with physical fitness the values ranged from: (R 2 = 0.23-0.64%). Percentiles per MS (P3, P5, P10, P15, P25, P50, P75, P85, P90, P95 and P97) were proposed for both BC and PF. Conclusion: The results of the study have shown that the evaluation of BC and PF of young soccer players should be performed by controlling for MS rather than for CA. The inclusion of a non-invasive method to control MS by means of percentiles during puberty may contribute to the development of retention and exclusion of young soccer players, thus, they may have a better chance of achieving sporting success.

Accuracy in body composition scanning by adult half-body DXA scanning.

Introduction: Introduction: dual-energy X-ray absorptiometry (DXA) is the gold standard method, although one limitation is the size of the scan area. Objective: the objective was to verify the accuracy of body composition (BC) scanning through half-body DXA scanning compared to standard total body scanning. Methods: a study was conducted on 145 volunteers. Weight and height were assessed. Body mass index (BMI) was calculated. DXA was used for whole-body scan (WBS) and half-body scan (HBS). WBS was used as the reference method and the following indicators were extracted: bone mineral content (BMC), fat mass (FM), lean soft tissue (LST) and percentage fat mass (%FM). Results: no differences were observed in the body composition indicators (BMC, FM, LST and %FM) when compared between the reference WBS scanner and the HBS scanner. The predictive power between both scans ranged in both sexes between R2 = 0.94 and 0.98. The DRI desirable reproducibility index values defining the degree of agreement between both scans ranged from 0.97 to 0.99, and the values for precision (0.97 to 0.99) and accuracy (0.99) were high. Conclusion: HBS scanning by DXA evidenced agreement, and high values of accuracy and precision to assess body composition indicators (BMC, FM, LST and %FM).

Introducción: Introducción: la absorciometría de rayos X de doble energía (DXA) es el método de referencia, aunque una limitación es el tamaño del área de exploración. Objetivo: el objetivo fue verificar la precisión de la exploración de la CB mediante la exploración DXA de medio cuerpo en comparación con la exploración estándar de todo el cuerpo. Métodos: se realizó un estudio con 145 voluntarios. Se evaluaron el peso y la altura. Se calculó el índice de masa corporal (IMC). Se utilizó la DXA para la exploración de cuerpo entero (WBS) y la exploración de medio cuerpo (HBS). Se utilizó la PEP como método de referencia y se extrajeron los siguientes indicadores: contenido mineral óseo (CMO), masa grasa (MG), tejido blando magro (TBL) y porcentaje de masa grasa (%MG). Resultados: No se observaron diferencias en los indicadores de composición corporal (BMC, FM, LST y %FM) cuando se compararon entre el escáner WBS de referencia y el escáner HBS. El poder predictivo entre ambos escáneres osciló en ambos sexos entre R2 = 0,94 y 0,98. Los valores del índice de reproducibilidad deseable DRI que definen el grado de acuerdo entre ambas exploraciones oscilaron entre 0,97 y 0,99, y los valores de precisión (0,97 a 0,99) y exactitud (0,99) fueron altos. Conclusión: la exploración de HBS mediante DXA evidenció concordancia y altos valores de exactitud y precisión para evaluar los indicadores de composición corporal (BMC, FM, LST y %FM).

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.

[Proposal of percentiles to evaluate physical growth and body adiposity as a function of maturity status in Chilean children and adolescents]. / Propuesta de percentiles para evaluar el crecimiento físico y la adiposidad corporal en función del estado de madurez en niños y adolescentes chilenos.

INTRODUCTION: Introduction: during childhood and adolescence there is great individual variability in growth and biological maturation, resulting in differences in size, shape and body composition in children and adolescents of similar age. Objective: to propose percentiles to assess physical growth and body adiposity as a function of maturity status (SM) in Chilean children and adolescents. Methods: a descriptive (cross-sectional) study was designed in 7,292 children and adolescents (4214 boys and 3084 girls) from the Maule region (Chile). The age range was 6.0 to 17.9 years. Weight, height and waist circumference (WC) were evaluated. Body mass index (BMI), waist-height index (WHtR) and SM were calculated through a non-invasive anthropometric technique based on chronological age and standing height. The LMS method was used to calculate percentiles. Results: the SM calculated in boys was observed at 13.7 ± 0.6 APHV (years of peak growth speed) and in girls at 12.1 ± 0.6 APHV. Percentiles were created for weight, height, WC, BMI, and WHtR. All anthropometric variables increase as MS increases in PHV years. Conclusion: the proposed percentiles are an alternative to evaluate physical growth and body adiposity as a function of SM in Chilean children and adolescents. The results suggest the use of this non-invasive technique to be applied in clinical and epidemiological contexts.

INTRODUCCIÓN: Introducción: durante la infancia y la adolescencia existe una gran variabilidad individual en el crecimiento y la maduración biológica, lo que resulta en diferencias en el tamaño, la forma y la composición corporal de los niños y adolescentes de edad similar. Objetivo: proponer percentiles para evaluar el crecimiento físico y la adiposidad corporal en función del estado de madurez (EM) en niños y adolescentes chilenos. Métodos: se diseñó un estudio descriptivo (transversal) en 7292 niños y adolescentes (4214 chicos y 3084 chicas) de la región del Maule (Chile). El rango de edad oscila entre 6,0 y 17,9 años. Se evaluó el peso, la estatura y la circunferencia de la cintura (CC). Se calculó el índice de masa corporal (IMC), el índice cintura-estatura (ICE) y el EM a través de una técnica antropométrica no invasiva basada en la edad cronológica y la estatura de pie. Se utilizó el método LMS para calcular los percentiles. Resultados: el EM calculado en los chicos se observó a los 13,7 ± 0,6 APVC (años de pico de velocidad de crecimiento) y en las chicas a los 12,1 ± 0,6 APVC. Se crearon percentiles para el peso, la estatura, la CC, el IMC y el ICE. Todas las variables antropométricas se incrementan conforme el EM aumenta en APVC. Conclusión: los percentiles propuestos son una alternativa para evaluar el crecimiento físico y la adiposidad corporal en función del EM en los niños y adolescentes chilenos. Los resultados sugieren que esta técnica no invasiva puede aplicarse en contextos clínicos y epidemiológicos.

Regulation data for the horizontal jump of children and adolescents.

The Horizontal Jump (HJ) is a daily tool that could be used to categorize the level of muscle fitness performance of the lower limbs. The goal was to compare the muscle fitness with those of international studies and to propose percentiles to assess the HJ performance of children and adolescents. A cross-sectional study was conducted. A total number of 3023 children and adolescents between the ages of 6.0 to 17.9 were studied. Weight, height, waist circumference (WC), and lower limb muscle fitness were evaluated. The student HJ performance values in Chile were inferior when compared to HJ performance in Brazil, Poland and Europe. For the Greek study, differences occurred only from age 6 to 15 years old. In comparison to Colombia, students showed better muscle fitness performance. These differences appeared in childhood and lasted until the beginning of adolescence. Percentiles were created to assess the lower limb fitness being an easy tool to be used and applied to classify lower limb strength.

[Estimation of fat mass by anthropometric indicators in young people with Down syndrome]. / Estimación de la masa grasa por medio de indicadores antropométricos en jóvenes con síndrome de Down.

INTRODUCTION: Introduction: the assessment of body composition is relevant and useful for designing interventions for healthy lifestyles and nutritional strategies. Objective: our goal was to verify the relationships between adiposity indicators with fat mass (FM), and to validate equations that allow predicting FM in young people with Down syndrome (SD). Methods: a cross-sectional study was carried out in 48 young people with DS (24 men and 24 women). Weight, height, waist circumference (WC), and hip circumference (HC) were evaluated. Body mass index (BMI), body adiposity index (BAI), waist-to-hip index (WHI), and waist-to-height index (WHtR) were calculated. FM was evaluated by dual energy X-ray absorptiometry (DXA). Results: age in men was 19.3 ± 3.0 years, and in women it was 18.9 ± 1.9 years; weight was 73.6 ± 14.3 kg in men and 75.8 ± 20.3 kg in women, and height in men was 168.9 ± 6.5 cm, and in women it was 156.3 ± 6.2 cm. In males the correlations between FM (DXA) with BMI, WC, HC, WHtR, BAI and WHtR ranged from r = 0.01 to r = 0.89, and in females from r = 0.10 to r = 0.97. The highest correlations were observed with BMI and WC in both sexes (males r = 0.78 to 0.92, and females r = 0.83 to 0.97). Regression equations were generated to estimate FM in males (R2 = 84 %) and in females (R2 = 96 %). Percentiles were calculated for MG per DXA and for each equation. Conclusions: there were significant positive correlations between BMI and WC with FM. These indicators were decisive for developing equations that estimate FM in young people with DS. The results suggest its potential use and application to evaluate, classify and monitor body fat levels in clinical and epidemiological contexts.

INTRODUCCIÓN: Introducción: la evaluación de la composición corporal es relevante y útil para diseñar intervenciones de estilos de vida saludables y estrategias nutricionales. Objetivos: verificar las relaciones existentes entre los indicadores de adiposidad y la masa grasa (MG), y validar ecuaciones que permitan predecir la MG en jóvenes con síndrome de Down (SD). Métodos: se efectuó un estudio transversal en 48 jóvenes con SD (24 hombres y 24 mujeres). Se evaluaron el peso, la estatura, la circunferencia de la cintura (CC) y la circunferencia de la cadera (CCa). Se calcularon el índice de masa corporal (IMC), el índice de adiposidad corporal (IAC), el índice cintura-cadera (ICC) y el índice cintura-estatura (ICE). Se evaluó la MG mediante absorciometría de rayos X de doble energía (DXA). Resultados: la edad de los hombres era de 19,3 ± 3,0 años y la de las mujeres de 18,9 ± 1,9 años; el peso era de 73,6 ± 14,3 kg en los hombres y de 75,8 ± 20,3 kg en las mujeres; finalmente, la estatura de los hombres era de 168,9 ± 6,5 cm y la de las mujeres de 156,3 ± 6,2 cm. En los hombres, las correlaciones entre la MG (DXA) y los parámetros IMC, CC, CCa, ICE, IAC e ICE oscilaron entre r = 0,01 y r = 0,89; en las mujeres, entre r = 0,10 y r = 0,97. Las correlaciones más altas se observaron con el IMC y la CC en ambos sexos (hombres, r = 0,78 a 0,92 y mujeres, r = 0,83 a 0,97). Se generaron ecuaciones de regresión para estimar la MG en los hombres (R2 = 84 %) y en las mujeres (R2 = 96 %). Se calcularon los percentiles de MG según la DXA y con cada ecuación. Conclusiones: hubo correlaciones positivas significativas del IMC y la CC con la MG. Estos indicadores fueron determinantes para desarrollar ecuaciones que estiman la MG de los jóvenes con SD. Los resultados sugieren su uso y aplicación para evaluar, clasificar y monitorizar los niveles de adiposidad corporal en contextos clínicos y epidemiológicos.

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.

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

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

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.