No abstract

Garcia-Hermoso, A, Cofre-Bolados, C, Andrade-Schnettler, R, Ceballos-Ceballos, R, Fernández-Vergara, O, Vegas-Heredia, ED, Ramírez-Vélez, R, and Izquierdo, M. Normative reference values for handgrip strength in Chilean children at 8-12 years old using the empirical distribution and the lambda, mu, and sigma statistical methods. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study was 2-fold (a) to provide sex- and age-specific handgrip reference standards for Chilean children aged 8-12 years and (b) to compare the levels of handgrip strength of Chilean children with those of children from other countries. This cross-sectional study enrolled 2,026 schoolchildren (boys n = 1,334 and girls n = 692, mean age 10.18 [1.16] years old). Handgrip strength was measured using a hand dynamometer with an adjustable grip. Relative handgrip strength was calculated by dividing handgrip strength by body mass (handgrip strength kg per mass kg). Smoothed centile curves and tables for the 10th, 20th, 30th, 40th, 50th, 60th, 70th, 80th, and 90th centiles were calculated using Cole's lambda, mu, and sigma method. The results indicate that mean handgrip strength was greater among boys than girls. Handgrip strength peaked at 16.25 (5.03) kg in boys and 14.90 (4.32) kg in girls. In addition, relative handgrip strength peaked at 0.38 (0.08) in boys and 0.34 (0.07) in girls. Chilean children of both sexes scored higher than their South American counterparts from Colombia and Peru but showed lower handgrip strength than European and Australian children. Our results provide, for the first time, sex- and age-specific handgrip reference standards for Chilean children aged 8-12.9 years. These normative reference values could help identify the levels of handgrip strength that need attention to provide appropriate feedback and advice to children about how to best improve their overall physical fitness.

Resilience is a psychological characteristic which enhances personal assets and protects individuals from potential negative effects of various stressors. While this topic has been considered in the separate context of sports injuries and anxiety states, these issues have rarely been considered together. The objective of this study is to analyse the association between motivation to overcome injuries in football and the state of anxiety caused by those injuries. One hundred and eighty-five footballers from Spain were analysed by way of the Connor-Davidson Resilience Scale, the State-Trait Anxiety Inventory questionnaires, and an injury self-registration sheet. Statistical analyses were performed using structural equations. Results showed a direct and positive relationship between the capacity to face up to injuries or potential injuries and to adapt successfully to them for injured footballers, especially when anxiety was considered as a transitory emotional state. In addition, this relationship was stronger in non-injured sportspersons because their resilience capacity was not being impaired by the experience of an injury.

Sedentarism, overweight and malnutrition generate an increase in the production of reactive oxygen species leading to a state of chronic oxidative stress. In patients with type 2 diabetes mellitus, oxidative stress alters pancreatic insulin secretion and the actions of the hormone on target cells, contributing to the development of micro and macrovascular complications. During physical exertion a state of transient oxidative stress occurs. As a consequence, the organism generates multiple physiological adaptations to these repetitive stimuli. Physical exercise is beneficial for type 2 diabetes mellitus but there is a paucity of information about the effects of physical exercise on biomarkers of oxidative stress in patients with the disease. We herein try to elucidate if the effects of exercise on oxidative stress can help in the prevention and treatment of type 2 diabetes mellitus and which is the most effective modality of physical exercise to reduce oxidative stress markers.

(Rev Med Chile 2017; 145: 327-334)

It is well known that physical exercise modifies plasma levels of testosterone and cortisol. However, the effect of high-intensity interval training (HIIT) on the plasma hormone levels is controversial. The aim of the study was to compare the effects of HIIT exercise or submaximal continuous aerobic exercise on circulating testosterone and cortisol levels in active male collegiate students. Methods: Thirteen moderately-active young adult males (20.2 (SD 2.1) years old) completed a HIIT (20 min of 15 s intervals of running at 110% of maximum oxygen consumption interspersed with 15 s of active rest at 40% of maximum oxygen consumption) and a continuous aerobic exercise (AEE) 20 min at 70–75% of maximum oxygen consumption. The mean total workload of both protocols was the same for each exercise session. Blood samples were collected pre-session (rest), immediately after the session (0 h), and 12 h post-session (12 h). Results: Both exercise protocols, similarly increased plasma levels of free testosterone immediately post-exertion (p < 0.05 AEE and p < 0.01 HIIT). No differences were observed between the conditions in the concentration of testosterone at 12 h. Cortisol level and Testosterone/Cortisol (T/C) ratio remained constant for all measurements, regardless of the type of exercise performed. Conclusion: The testosterone concentrations rose significantly post intervention in both HIIT and AEE condition, but 12 h post intervention there was no difference between conditions, decreasing to baseline (pre-intervention). The T/C ratio decreased significantly (below baseline) only in the HIIT condition 12 h post intervention.

Introduction: Society is currently experiencing significant reductions in physical activity levels and increases in sedentary behavior are associated with obesity. Objective: The aim of this study was to identify the prevalence of overweight and obesity in a group of school children in Santiago, Chile and explore the relationship between body composition, physical activity and physical fitness. Material and methods: Research was conducted with a representative sample of 515 students (10.6 ± 0.5 age-old). Data included their anthropometric measurements (BMI and fat percentage), physical activity, and physical fitness (aerobic capacity, lower-body and upper-body explosive strength). Results: About 55% of the sample was overweigh/obesity. Male students and students with normal body weight fared better in physical fitness tests than females and those who suffered from overweight or obesity. We found inverse relationships between the PAQ-C score and anthropometric parameters and between anthropometric parameters and physical fitness. Conclusion: Given the alarming levels of childhood overweight and obesity detected in Santiago and the relationship between physical fitness and body composition it is important to design interventions which can induce improvements in physical fitness, and specifically target females and children with obesity.

La transición epidemiológica observada en las últimas décadas ha implicado un aumento creciente de enfermedades crónicas, fenómeno asociados con el estilo de vida de la población, al modelo alimentario y al sedentarismo, lo que predispone a la obesidad y a la resistencia a la insulina, condicionando patologías cardio metabólicas como la hipertensión arterial y la dislipidemia, favoreciendo el desarrollo del síndrome metabólico. El tratamiento consiste en el manejo farmacológico, mejoras en los hábitos alimentarios y la incorporación de la actividad física a la rutina diaria. Tradicionalmente los programas de ejercicio están orientados a un método aeróbico para mejorar los parámetros alterados. Sin embargo, actualmente han surgido nuevas estrategias de intervención como el entrenamiento interválico de alta intensidad, que ha evolucionado como un modelo de intervención eficaz, con real impacto en el estado de salud de la población. El objetivo de esta revisión es entregar una mirada histórica y actualizada del ejercicio interválico de alta intensidad, de su impacto en la población y de las adaptaciones fisiológicas que respaldan su uso como herramienta terapéutica.Palabras claves: Entrenamiento aeróbico interválico de alta intensidad, síndrome metabólico, prescripción de ejercicio.