A high level of physical fitness in childhood and adolescence is associated with more favorable physical and mental health outcomes. Objective: To compare body adiposity and horizontal jump performance with international studies and to analyze the relationship between body adiposity and horizontal jump performance indicators in children and adolescents. Patients and Method: Descriptive study conducted on 812 adolescents from Talca (Chile), with an age range between 10.0 and 16.9 years. Weight, height, waist circumference (WC) and Horizontal jump (HJ) were evaluated after warm-up for 10 to 15 minutes to evaluate the explosive strength of the lower extremities according to the protocol of Castro-Piñero et al. Adiposity and HJ were compared with national and international studies. The data normality was verified by the Kolmogorov-Smirnov test. Smoothed percentile curves (p50) were created for BMI, WC, and HJ for each gender according to the LMS method. Results: Adolescents showed differences in body adiposity and HJ performance with international studies. In both genders, negative and significant correlations were found between the BMI and the HJ (men r =-0.104 and women r =-0.149) and between the WC and the HJ (men r =-0.100 and women r =-0.131). The adolescents who were classified in tertile 1 (good) and tertile 2 (satisfactory) had lower body adiposity (BMI and WC) and better HJ performance than those in tertile 3 (poor). Conclusion: Higher body adiposity and lower HJ performance were observed compared to international studies. In addition, a negative relationship between body adiposity and HJ was found. These findings suggest that the progressive increase of adiposity as age increases negatively affects the strength performance of the lower extremities of the studied children and adolescents.

Introduction: Regular physical activity (PA) during childhood and adolescence is important for the prevention of non-communicable diseases and their risk factors. Objectives: To validate a questionnaire that measures PA patterns, to verify its reliability, compare the levels of PA aligned with chronological and biological age, and develop percentile curves to assess PA levels, depending on biological maturation. Subjects and Method: Descriptive cross-sectional study was performed on a non-probabilistic quota sample of 3,176 Chilean adolescents (1685 males and 1491 females), with a mean age range from 10.0 to 18.9 years. An analysis was performed on, weight, standing and sitting height. The biological age through the years of peak growth rate and chronological age in years was determined. Body Mass Index was calculated and a survey of PA was applied. The LMS method was used to develop percentiles. Results: The values for the confirmatory analysis showed saturations between 0.517 and 0.653. The value of adequacy of Kaiser-Meyer-Olkin (KMO) was 0.879 and with 70.8% of the variance explained. The Cronbach alpha values ranged from 0.81 to 0.86. There were PA differences between the genders when aligned by chronological age. There were no differences when aligned by biological age. Percentiles are proposed to classify the PA of adolescents of both genders according to biological age and sex.

A soccer player should possess a reasonable level of different skills and abilities, so the playing position, level of training, style of play, physical and physiological demands can influence his performance. The objective was to identify the intervention programs that have been applied in search of generating positive effects on explosive strength and speed in young soccer players, as well as to identify the percentage of improvement among soccer players. A bibliographic study of systematic review was carried out. Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, bibliographic searches were performed in the PubMed database. The following descriptors were used: Explosive Strength, soccer players, jump performance, CMJ, SJ, VJ, Plyometrics, power, speed, sprint, kicking speed, change of direction speed, soccer player, football and training, intervention. Articles were included only if they were original articles, studied populations of young soccer players and showed an intervention program related to explosive strength and speed. Six studies were identified that applied intervention programs to look for changes in speed and explosive strength in young soccer players. In the 5m speed tests, significant changes were observed, improving from (0.26 to 0.53m/s), 10m speed (0.07 to 0.27m/s), 20m speed (0.08 to 1.92m/s) and 40m speed (0.25 to 0.62m/s). In explosive strength, performance in the test squat jump SJ (4.1 to 8.6cm), countermovement jump CMJ (1.0 to 8.8cm), horizontal jump HJ (12.17 to 24.4cm) and vertical jump VJ (5.0 to 11.0cm). Speed and explosive strength are relevant components of athletic performance and can be improved through training programs that include 20 to 40min sessions, training two to five times per week over a period of approximately 6 to 9 weeks.

Introduction Aerobic fitness is an important predictor that contributes to the preservation of functional independence during the aging process. Its measurement represents a fundamental tool in the identification of multiple health problems. Objective To compare the aerobic capacity of adults and elderly subjects through international studies and to develop percentiles by age group using the LMS method. Methods A cross-sectional descriptive study was conducted with 1146 subjects (437 men and 709 women). The age group of the sample ranged from 50 to 84 years. The subjects evaluated came from the physical activity programs offered by the National Sports Institute (IND) and by the city council of Talca (Chile). Body mass, stature, oxygen saturation (SatO2), six-minute walk test, and systolic and diastolic blood pressure were assessed. Body Mass Index (BMI) was calculated for both sexes. The LMS method was used to propose the percent distribution. Results Aerobic capacity decreases with age (28.5% for men and 29.9% for women). There was a negative relationship between age and the six-minute walk test (men r = -0.13 and women r = -0.39). There was a discrepancy between the elderly subjects in the current study and those from international studies. The normative data for the classification of aerobic fitness were expressed in percentiles (p3, p5, p10, p15, p25, p50, p75, p85, p90, p95 and p97). Conclusion The aerobic performance of elderly subjects diminishes as they age; in addition, the current results differ from international studies, which motivated the development of percentiles to classify aerobic fitness in everyday situations, especially in places with few resources and particularly where field tests are considered a priority for large-scale physical evaluation. Level of evidence II; Diagnostic studies – investigation of diagnostic test.

Introducción: Comparar el perfil antropométrico de cuatro modalidades deportivas y verificar la aplicabilidad del Índice de Masa Corporal e Índice Ponderal de jóvenes universitarios participantes de las selecciones universitarias de Chile. Material y Métodos:Se efectuó un estudio descriptivo (comparativo-correlacional). Fueron estudiados 66 jóvenes universitarios deportistas de Chile (37 hombres y 29 mujeres) con un rango de edad entre 18 a 28 años. Los deportes incluidos fueron: baloncesto, voleibol, taekwondo y judo. Se evaluó el peso y estatura. Se calculó el Índice de Masa Corporal (IMC=peso [kg]/estatura 2 [m]) y el Índice Ponderal (IP=peso [kg]/estatura 3 [m]).Resultados: Hubo diferencias antropométricas en las cuatro modalidades deportivas y en ambos sexos. El peso influye sobre el IMC en hombres (R 2 =55%) y en mujeres (R 2 = 76%), mientras que, en el IP, el peso y estatura influyen en hombres (R 2 = 15 y 14%) y el peso en mujeres (R 2 = 44%). Conclusiones:Se observó diferencias antropométricas en atletas universitarios de baloncesto, voleibol, taekwondo y judo de ambos sexos, además el IP permitió corregir las variaciones del peso y estatura en relación al IMC. Introduction:To compare the anthropometric profile of four sports modalities and verify the applicability of the Body Mass Index and Weight Index of university students participating in the university selections of Chile. Material and Methods:A descriptive (comparative-correlational) study was carried out. Sixty-six university athletes from Chile (37 men and 29 women) with an age range between 18 and 28 years were studied. The sports included were: basketball, volleyball, taekwondo and judo. Weight and height were evaluated. The Body Mass Index (BMI=weight [kg]/height 2 [m]) and the weight index (IP=weight[kg]/height 3 [m]) were calculated.Results: There were anthropometric differences in the four sports modalities and in both sexes. The weight influences the BMI in men (R 2 =55%) and in women (R 2 =76%), while in the IP, weight and height influence men (R 2 =15 and 14%) and weight in women (R 2 =44%). Conclusions:Anthropometric differences were observed in university athletes of basketball, volleyball, taekwondo and judo of both sexes, besides the IP allowed correcting the variations of the weight and stature in relation to the BMI.