A systematic review of intervention programs that produced changes in speed and explosive strength in youth footballers.

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.

Physical activity and medication in Brazilians suffering with non-communicable diseases in quarantine by COVID-19.

This study aimed to compare the practice of physical activity in groups of people with chronic diseases with and without medication, before and during the pandemic. 298 Brazilian individuals with chronic non-communicable diseases such as cardiovascular, metabolic / endocrine, respiratory, orthopedic, gastrointestinal diseases, anxiety and depression were separated into two groups: with and without medication. A questionnaire with 14 questions was applied, tracing the behavioral profile in relation to physical exercises before and during isolation, interpreted through descriptive analysis, and the groups were compared through Mann-Whitman's statistics. The drop in the percentage of active individuals with or without medication occurred when comparing the scenarios before and during quarantine. However, the difference in the prevalence of active individuals between the groups was significant, showing that the group with medication remained more active. The fear of contamination, the measures of distance and the lack of adherence of the population to classes by videoconference reduced the frequency of physical activities in the general sample population. However, people who used medication showed greater concern about the practice of physical activity to optimize treatment. The isolation period had a negative impact on the practice of physical activity, regardless of the presence of some chronic disease or the use of medication.

Crecimiento físico y composición corporal de jóvenes beisbolistas brasileros por edad cronológica y estado de madurez / Physical growth and body composition of young Brazilian baseball players by chronological age and maturity stage

Introducción: El crecimiento físico (CF), maduración biológica (MB) y la composición corporal (CC) son indicadores de salud que deben ser controlados para detectar anomalías individuales y para la selección y detección de talentos deportivos. El objetivo fue verificar si los parámetros de CF y la CC de jóvenes beisbolistas deben ser analizados por estado de madurez antes que por edad cronológica como lo sugieren las investigaciones. Métodos: Se efectuó un estudio descriptivo transversal en102 niños y adolescentes Beisbolistas de 9.0 a 15.0 años. La selección de la muestra fue no probabilística (conveniencia). Se evaluó el peso, la estatura de pie, estatura sentada, pliegues tricipital, subscapular. Se calculó el estado de madurez por la técnica antropométrica de Mirwald. El porcentaje de grasa (%G), masa grasa (MG) y masa libre de grasa (MLG) fueron estimados por ecuaciones de regresión. Resultados: El promedio de edad cronológica fue de 12,2±2,2 años, el estado de madurez fue alcanzado a los 14,8±0,5APVC y los años de experiencia en la modalidad deportiva fue de 5,6±2,2 años. Se determinaron 5 niveles de estado de madurez: -4APVC, -3APVC, -2APVC, -1APVC Y 0APVC. Los niños clasificados como púberes reflejaron valores superiores de peso, estatura, MG y MLG en comparación con los pre púberes (p<0,05).Conclusión: El estudio demostró que la evaluación del estado de madurez en jóvenes beisbolistas por medio de una técnica antropométrica no-invasiva es esencial para disminuirlos factores de confusión ocasionados por la edad cronológica, principalmente cuando se estudia el CF y la CC durante la adolescencia. (AU)

Introduction: Physical growth (FC), biological maturation (BM) and body composition (BC) are health indicators that should be monitored to detect individual abnormalities and for the selection and detection of sports talent. The objective was to verify whether the parameters of FC and CC of young baseball players should be analyzed by maturity status rather than by chronological age as suggested by research. Methods: A descriptive cross-sectional study was carried out in 102 children and adolescent baseball players aged 9.0 to 15.0 years. The sample selection was non-probabilistic (convenience). Weight, standing height, sitting height, tricipital and subscapular folds were evaluated. Maturity status was calculated by the Mirwald anthropometric technique. Fat percentage (%G), fat mass (FM) and fat-free mass (FFM) were estimated by regression equations. Results: The average chronological age was 12.2±2.2 years, the maturity stage was reached at 14.8±0.5APVC and the years of experience in the sport modality was 5.6±2.2 years. Five levels of maturity status were determined: -4APVC, -3APVC, -2APVC, -1APVC and 0APVC. Children classified as pubertal reflected higher values of weight, height, MG and GLM compared to pre-pubertal (p<0.05). Conclusion: The study demonstrated that the evaluation of maturity status in young baseball players by means of a non-invasive anthropometric technique is essential to reduce the confounding factors caused by chronological age, mainly when CF and CC are studied during adolescence. (AU)

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 researchers.

Physical Growth and Biological Maturation of Children and Adolescents: Proposed Reference Curves.

BACKGROUND/AIM: The study of physical growth variables in terms of chronological age and biological maturation may provide a common reference point to reflect on the occurrence of body dimensions in and between individuals. The objectives of this study were as follows: (a) verify if the observed gender differences in the variables of physical growth by chronological age are confounded by physical maturation, (b) compare physical growth patterns with the reference of the Centers for Disease Control and Prevention (CDC)-2012, and (c) develop regional curves to assess physical growth in terms of biological maturation. METHODS: Researchers studied 3,674 children and adolescents. Weight, standing height, and sitting height were measured. Biological maturation was determined by using the age of peak velocity growth. Body mass index (BMI) was calculated. Growth variables were compared with the CDC-2012 reference. Percentiles were calculated by the LMS method. The students differed in weight and BMI when compared to the reference individuals. The differences in weight, standing height, and BMI between both genders are more pronounced when they are aligned with biological age rather than chronological age. CONCLUSION: Weight and BMI differ from the reference. Furthermore, the assessment of the physical growth trajectory should be analyzed in terms of biological maturation. The proposed regional curves may be used in and applied to clinical and epidemiological contexts.