Fuerza muscular y porcentaje de grasa corporal en niños y adolescentes de la región del Maule, Chile / Muscle strength and body fat percentage in children and adolescents from the Maule region, Chile

Objetivo. Analizar la asociación entre la fuerza de prensión manual relativa (FPMR) y la masa grasa (MG), controlando el posible efecto del estado de madurez.Metodología. Se estudiaron niños y adolescentes de ambos sexos con un rango de edad de ≥ 7,5 a ≤ 15,49 años. Se evaluó la FPMR mediante un dinamómetro hidráulico manual. El porcentaje de MG se evaluó mediante la absorciometría de rayos X de doble energía. Para analizar las diferencias por sexo y grupo etario y entre los niños normopesos y obesos en los niveles de FPMR, se utilizó el análisis de covarianza. Se consideraron como covariable los años de pico de velocidad de crecimiento (estado de madurez). Para analizar la asociación entre los niveles de FPMR y MG, se utilizó la correlación parcial, controlando el año de pico de velocidad de crecimiento.Resultados. Participaron 1685 escolares (731 mujeres y 954 varones). Fueron conformados 4 grupos de edad (7,5-9,4 años; 9,5-11,4 años; 11,5-13,4 años y 13,5-15,4 años). La FPMR aumentó con la edad en ambos sexos. Los valores de MG fueron elevados en todos los grupos etarios. No hubo diferencias en los grupos 3 y 4 en las niñas y en el grupo 4 de los niños. Los niños clasificados como peso normal presentaron significativamente mayor FPMR que los obesos. Se observó una asociación negativa entre FPMR y MG.Conclusión. Se demostró que la FPMR estaba negativamente asociada con la MG, tras controlar el efecto del estado de madurez

Objective. 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 FM.Conclusion. RHGS was shown to be negatively associated with FM after controlling for the effect of maturity status

Muscle strength and body fat percentage in children and adolescents from the Maule region, Chile. / Fuerza muscular y porcentaje de grasa corporal en niños y adolescentes de la región del Maule, Chile.

Objective: 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 FM. Conclusion: RHGS was shown to be negatively associated with FM after controlling for the effect of maturity status.

Objetivo. Analizar la asociación entre la fuerza de prensión manual relativa (FPMR) y la masa grasa (MG), controlando el posible efecto del estado de madurez. Metodología. Se estudiaron niños y adolescentes de ambos sexos con un rango de edad de ≥ 7,5 a ≤ 15,49 años. Se evaluó la FPMR mediante un dinamómetro hidráulico manual. El porcentaje de MG se evaluó mediante la absorciometría de rayos X de doble energía. Para analizar las diferencias por sexo y grupo etario y entre los niños normopesos y obesos en los niveles de FPMR, se utilizó el análisis de covarianza. Se consideraron como covariable los años de pico de velocidad de crecimiento (estado de madurez). Para analizar la asociación entre los niveles de FPMR y MG, se utilizó la correlación parcial, controlando el año de pico de velocidad de crecimiento. Resultados. Participaron 1685 escolares (731 mujeres y 954 varones). Fueron conformados 4 grupos de edad (7,5-9,4 años; 9,5-11,4 años; 11,5-13,4 años y 13,5-15,4 años). La FPMR aumentó con la edad en ambos sexos. Los valores de MG fueron elevados en todos los grupos etarios. No hubo diferencias en los grupos 3 y 4 en las niñas y en el grupo 4 de los niños. Los niños clasificados como peso normal presentaron significativamente mayor FPMR que los obesos. Se observó una asociación negativa entre FPMR y MG. Conclusión. Se demostró que la FPMR estaba negativamente asociada con la MG, tras controlar el efecto del estado de madurez.

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

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