Parameters of pubertal growth spurt in children and adolescents living at high altitude in Peru.

OBJECTIVES: The aim was to estimate the pubertal growth height of children and adolescents living in a high-altitude region of Peru using the Preece-Baines model 1 (1 PB). METHODS: A cross-sectional study was conducted in schoolchildren from the department of Puno (Peru) between 3841 and 3874 masl. The age range was between 4 and 17 years. Standing height was evaluated. 1 PB was used to infer the mathematical and biological parameters of stature. RESULTS: Mathematical parameters estimated by the 1 PB model reflected small residual standard error (RSE) values in both sexes (0.25 in boys and 0.27 in girls). In boys, the age at which peak velocity was reached (APHV) was estimated at 13.21 ± 0.33years. While in girls it was 9.96 ± 0.26years (p < 0.05). In general, girls reached APHV (y) 3.25 years earlier than boys. On the other hand, the growth velocity of maximum height [APHV (cm/y)] of boys was higher (6.33 ± 6.06 cm/y) relative to girls (6.06 ± 0.32 cm/y). Estimated final adult height (EFAH) in boys was reached at 166.020 ± 0.99 cm and height at maximum growth velocity (HPHV) was 153.07 ± 0.67 cm, while in girls they were significantly lower (EFAH; 153.74 ± 0.44 cm and HPHV: 139.73 ± 0.84 cm). CONCLUSIONS: This study showed that girls living in Puno at a high altitude in Peru reached APHV 3 years earlier than boys and at the same time reflected slower PHV. These results suggest that pubertal growth at high altitudes is slower in both sexes and especially in girls. Thus, modeling physical growth may be an important step in understanding the onset of puberty at different latitudes.

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

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

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

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.