(Rev Med Chile 2017; 145: 972-979)

Diversas investigaciones han determinado que la implementación de programas de actividad física mejora la salud mental. Sin embargo, aún existen dudas sobre los beneficios de los programas Zumba® en la población que lo practica. El propósito de este estudio fue determinar los efectos de un programa de ejercicio físico basado en Zumba®, sobre los niveles de ansiedad-rasgo y ansiedad-estado en estudiantes universitarias chilenas. Investigación cuantitativa cuasi-experimental, con una muestra de 22 estudiantes mujeres de pregrado (grupo experimental = 10 y grupo control = 12). Las variables fueron: ansiedad-rasgo (A-R) y ansiedad-estado (A-E), además de variables físicas como antropometría, consumo máximo de oxígeno (VO2máx) y fuerza prensil. El análisis estadístico se realizó a través de un ANOVA mixto para todas las variables. En nivel de significancia fue de p < 0,05. Los resultados evidenciaron cambios no significativos en los distintos niveles de A-R ni A-E luego de la aplicación del programa de Zumba® (p > 0,05), tampoco hubo cambios en las otras variables de estudio (p > 0,05). Al término de la intervención, no se observaron efectos del programa de Zumba® sobre los distintos niveles de A-R y A-E, como tampoco sobre variables antropométricas, VO2máx ni fuerza prensil. Several investigations have specified that the implementation of physical activity programs improve mental health. However, there are still doubts about the benefits on the population taking part in Zumba® programs. The purpose of this study was to determine the effects of a Zumba® based working out program on the levels of anxiety-trait and anxiety-state in Chilean university students. It was a quantitative, cuasi-experimental study with a sample of 22 undergraduate female students (experimental group = 10 and control group = 12). The variables were anxiety-trait (A-T) and anxiety-state (A-S), in addition to physical variables, such as anthropometry, maximum oxygen consumption (VO2max) and grip strength. A statistical analysis was performed through a mixed ANOVA. The level of significance for all analyses was p < 0.05. The results showed no significant changes in the different levels of A-T or A-S (p > 0.05), there were also no changes in the other variables (p > 0.05). At the end of the intervention, no effects of the Zumba® program were observed on the different levels of A-T and A-S, nor on anthropometric variables, VO2max or grip strength. Várias investigações determinaram que a implementação de programas de atividade física melhora a saúde mental. No entanto, ainda existem dúvidas sobre os benefícios dos programas Zumba® na população que pratica. O objetivo deste estudo foi determinar os efeitos de um programa de exercícios físicos baseado no Zumba®, sobre níveis de Ansiedade-Traço e Ansiedade-Estado em estudantes universitários chilenos. Pesquisa quantitativa quase experimental, com uma amostra de 22 estudantes do sexo feminino (grupo experimental [GE] = 10 e grupo controle [GC] = 12). As variáveis foram: Ansiedade-Traço (A-T) e Ansiedade-Estado (A-E), ambas avaliadas pelo STAI Trait State Anxiety Questionnaire, além de variáveis físicas como antropometria, consumo máximo de oxigênio (VO2máx) e força pré-trilateral. A análise estatística foi realizada através de uma ANOVA mista para todas as variáveis e uma tabela de contingência por meio do Qui-Quadrado de Pearson para os diferentes níveis de A-T e A-E. O nível de significância para todas as análises foi de p <0,05. Os resultados não mostraram alterações significativas em todas as variáveis do estudo após a aplicação do programa Zumba® (p> 0,05); também não houve diferenças nos diferentes níveis de A-T ou A-E (p> 0,05). Ao final da intervenção, não foram observados efeitos do programa Zumba® sobre diferentes níveis de A-R e A-E, nem nas variáveis antropométricas, VO2máx ou força preênsil.

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The objectives of this study were: (a) to determine asymmetries, both lower limb (LL) and upper limb (UL), in Chilean older adults, and (b) to relate asymmetries to FA in both LL and UL. Forty-one older adults voluntarily participated in this study (mean ± standard deviation [SD]: age 72.0 ± 8.0 years, LL asymmetries 13.78 ± 14.87%, UL asymmetries 10.70 ± 8.85%, FA 40.35 ± 16.26 points). The variables were: (1) asymmetries of LL and UL, assessed through a force platform and handgrip, respectively; (2) FA, assessed through the Latin American Group for Maturity (GDLAM) and the GDLAM index of autonomy (GI) protocol. The relationship between the variables was performed through Spearman’s correlation. The analysis showed that 39% of the participants presented asymmetries above 15% in the LL. Likewise, this 39% of older adults presented a lower FA than their peers with asymmetries below 15% in the LL (≤15%: 35.64 ± 12.26 points vs. >15%: 47.69 ± 19.23 points, p = 0.003). The analysis showed a small correlation between LL and GI asymmetries (r = 0.27, p = 0.07) and a small but negative correlation between UL and GI (r = −0.21). The mean values of asymmetries of both LL and UL are within ‘normal’ parameters. However, several older adults were identified as being at risk. In parallel, older adults who presented a higher level of asymmetries in LL showed a lower level of FA.

[Purpose] The purpose of this study was to determine the behavior of creatine kinase before and after the execution of a pre-activation protocol with intra-set variable resistance in order to generate post-activation potentiation in female athletes. [Participants and Methods] Six sprint women were part of the study. The study had a quasi-experimental intra-participant design. The experimental condition included a pre-activation with intra-set variable resistance + 1 minute rest + 30-m sprint × 3. The variables were metabolic creatine kinase, total creatine kinase, and 30-m sprints. [Results] Both the experimental condition and the control condition showed an increase in creatine kinase and total creatine kinase 24 hours post-effort. Only the experimental condition showed improvement in 30-m sprints after the pre-activation with intra-set variable resistance. [Conclusion] All those sessions oriented to increasing strength levels with a pre-activation protocol through intra-set variable resistance must consider rests longer than 24 hours between sessions in order not to increase creatine kinase in female athletes significantly.

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Introduction The squat is an exercise that is widely used for the development of strength in sports. However, considering that not all sports gestures are vertical, it is important to investigate the effectiveness of propulsive force stimuli applied in different planes. Objective The main purpose of this study was to determine the influence of maximum isometric force (MIF) exerted on starting blocks over performance in 5, 10 and 20-meter sprints. Methods Seven high-level male sprinters (mean age ± SD = 28 ± 5.77 years) participated in this study. The variables were: a) MIF in squats and on starting blocks (measured using a functional electromechanical dynamometer [FEMD]), b) time in 5, 10 and 20-m sprints and c) jump height (measured by the squat jump test). For data analysis, a Pearson correlation was performed between the different variables. The criteria for interpreting the strength of the r coefficients were as follows: trivial (<0.1), small (0.1−0.3), moderate (0.3−0.5), high (0.5−0.7), very high (0.7−0.9), or practically perfect (>0.9). The level of significance was p < 0.05. Results There was very high correlation between MIF exerted on starting blocks and performance in the first meters of the sprint (5-m: r = -0.84, p = 0.01). However, there was small correlation between MIF in squats and performance in the first meters of the sprint (5-m: r = -0.22, p < 0.62). Conclusion The MIF applied on starting blocks correlates very high with time in the first meters of the sprint in high-level athletes. In addition, the use of the FEMD provides a wide range of possibilities for evaluation and development of strength with a controlled natural movement. Level of evidence IV; Prognostic Studies - Case series.

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