Acute effects of the intensity in the agonistantagonist paired-set on the neuromuscular performance / Efeito agudo da intensidade no sistema agonista-antagonista pareado por série sobre o desempenho neuromuscular

The intensity employed in the agonist-antagonist paired-set (AAPS) system may influence neuromuscular performance due to increased fatigue and decreased antagonist coactivation. However, it is not yet known whether performing submaximal repetitions at different intensities (i.e., wit h out m uscle failure) negatively affects agonist muscle performance. The aim of this study was to verify the acute effect of the AAPSsystem performed at different intensities with submaximal repetitions. 20 trained m ales in resistance training (RT) (21.8 [3.1] years; 76.9 [9.7] kg; 1.7 [0.0] m; 24.3 [2.6] kg/m2 ) participated of this investigation. All the participants were allocated in a randomized order in one of the two AAPS configurations: high-load (HL) or low-load (LL). In the HL condition, the individuals were submit t ed to one set of eight repetitions at 75% of one-repetition maximum (1RM) in the knee flexion (i.e., antagonist), followed by 75% 1RM knee extension (i.e., agonist) exercise until momentary concentric failure. In t he LL condition, they performed one set of 12 repetitions at 50% 1RMin the knee flexion, followed by knee extension at 75%1RM also until momentary concentric failure. Both experimental conditions p resented similar values for the number of repetitions, without significant difference (p= 0.66, ES= 0.15). Thus, our data suggest that the adoption of AAPS system without an increase of the antagonist fatigue and consequently no reduction of coactivation, acutely, may not lead to increased p erfo rm an ce o f target musculature during a resistance exercise session...(AU)

A intensidade empregada no sistema agonista-antagonista pareado por série ( AAPS) pode influenciar o desempenho neuromuscular devido ao aumento da fadiga e diminuição da co ativação do antagonista. No entanto, ainda não se sabe se realizar repetições submáximas em diferentes intensidades (i.e., sem falha muscular) afeta negativamente o desempenho muscular. O objetivo deste estudo foi verificar o efeito agudo do sistema AAPS realizado em diferentes intensidades com repetições submáximas. 20 homens treinados em treinamento resistido (TR) (21.8 ± 3.1 anos; 76.9 ± 9.7 kg; 1.7 ± 0.0 m; 24.3 ± 2.6 kg/m2 ) participaram desta investigação. Todos os participantes foram alocados, de forma aleatória, em uma das duas configurações do sistema AAPS: alta-carga (AC) ou baixa- carga (BC). Na condição AC, os indivíduos foram submetidos a uma série de oito repetições a 75% 1RMno exercício de flexão do joelho (i.e., antagonista), seguido por uma série a 75% 1RM de extensão do joelho até a falha oncêntrica momentânea. Ambas as condições experimentais apresentaram v alores sim ilares para o número de repetições, sem diferença significante (p = 0.66, TE = 0.15). Assim, nossos dados sugerem que a adoção do sistema AAPSsem aumento da fadiga do antagonista e consequentemente sem redução da coativação, agudamente, pode não levar ao aumento do desempenho da musculatura alvo durante uma sessão de exercício resistido...(AU)

Health self-perception and its association with physical activity and nutritional status in adolescents / Autopercepção de saúde e sua associação com atividade física e estado nutricional em adolescentes

Abstract Objective: To evaluate the association between total physical activities, physical activity in free time and nutritional status with self-perceived health in adolescents of both genders. Methods: This is a quantitative study that integrates the school-based, cross-sectional epidemiological survey with statewide coverage, whose sample consisted of 6261 adolescents (14 -19 years old) selected by random conglomerate sampling. Data were collected using the Global School-based Student Health Survey. The chi-squared test (χ 2) and the Poisson regression model with robust variance were used in the data analyses. Results: It was observed that 27.3% of the adolescents had a negative health self-perception, which was higher among girls (33.0% vs. 19.0%, p < 0.001). After adjusting for potential confounding factors, it was observed that boys who did not practice physical activity during free time (PR = 1.44, 95% CI: 1.15 -1.81) and were classified as insufficiently active (PR = 1.27, 95% CI: 1.04 -1.56), as well as girls who did not practice physical activity during free time (PR = 1.15, 95% CI: 1.02 -1.29) and were classified as overweight (PR = 1.27, 95% CI: 1.01 -1.29) had a greater chance of negative health self-perception. Conclusion: Behavioral issues may have different effects on health self-perception when comparing boys with girls. Negative health self-perception was associated with nutritional status in girls and a lower level of physical activity in boys, and the practice of physical activity in the free time was considered a protective factor against a negative health self-perception for adolescents of both genders.

Resumo Objetivo: Avaliar a associação entre atividade física total, atividade física no tempo livre e estado nutricional com a autopercepção de saúde em adolescentes de ambos os sexos. Métodos: Trata-se de um estudo com abordagem quantitativa, que integra o levantamento epidemiológico transversal de base escolar e abrangência estadual, cuja amostra foi constituída por 6.261 adolescentes (14 a 19 anos) selecionados por meio de uma estratégia de amostragem aleatória de conglomerados. Os dados foram coletados a partir do questionário Global School-based Student Health Survey. O teste de qui-quadrado (χ2) e o modelo de regressão de Poisson com variância robusta foram usados nas análises dos dados. Resultados: Observou-se que 27,3% dos adolescentes tinham uma autopercepção de saúde negativa, maior entre as meninas (33,0% vs. 19,0%; p < 0,001). Após o ajuste pelos potenciais fatores de confusão, constatou-se que tinham maior chance de ter uma autopercepção de saúde negativa os meninos que não praticavam atividade física no tempo livre (RP = 1,44; IC 95%: 1,15-1,81) e que eram classificados como insuficientemente ativos (RP = 1,27; IC 95%: 1,04-1,56) e as meninas que não praticavam atividade física no tempo livre (RP = 1,15; IC 95%: 1,02-1,29) e que eram classificadas como sobrepesadas (RP = 1,27; IC 95%: 1,01-1,29). Conclusão: Questões comportamentais podem ter diferentes repercussões na autopercepção de saúde quando comparados os meninos e meninas. A autopercepção de saúde negativa esteve associada ao estado nutricional entre as meninas e a um menor nível de atividade física entre os meninos e a prática de atividade física no tempo livre foi tida como fator de proteção para uma autopercepção de saúde negativa para os adolescentes de ambos os sexos.

Acute blood pressure responses after different isometric handgrip protocols in hypertensive patients

OBJECTIVE: The present study analyzed blood pressure responses after a single session of isometric handgrip exercise performed with different volumes and intensities by patients with hypertension. METHODS: This randomized crossover trial submitted 12 hypertensive patients (58±5 years old) to four isometric handgrip exercise sessions in a random order: 4 x 2 min at 30% of the maximal voluntary contraction (S30%); 4 x 2 min at 50% of the maximal voluntary contraction (S50%2min); 4 x 3 min at 30% of the maximal voluntary contraction (S30%3min); and a control session. The systolic and diastolic blood pressure, heart rate, and rate-pressure product were measured pre- and post-exercise (30th min). RESULTS: No significant changes were observed in cardiovascular variables after any session (p>0.05 for all comparisons). Similarly, individual analyses revealed heterogeneity in the responses, including increases in blood pressure observed in some sessions. Patients with reduced blood pressure after an isometric handgrip exercise session exhibited a higher body mass index, diastolic blood pressure and heart rate (p<0.05). They also tended to be younger (p=0.07). CONCLUSION: Isometric handgrip exercise performed with different intensities and volumes did not reduce the blood pressure of hypertensive patients.

Effects of isometric handgrip training in patients with cardiovascular disease: rationale and design of the ISOPRESS network

Meta-analytical studies have indicated that isometric handgrip training promotes significant reduction in blood pressure in hypertensive patients with similar or greater decreases in blood pressure than observed after aerobic and dynamic resistance training. However, several gaps in the literature still need to be addressed. Thus, we designed the ISOPRESS network group, which consists of a task force of different research groups aimed at analyzing the effects of isometric handgrip training on different contexts, parameters, and populations. Thus, the aim of this study was to describe the rationale and design behind the ISOPRESS, presenting the methods employed. The ISOPRESS questions involve whether isometric handgrip training is effective in hypertensives in different settings (ISOPRESS 1 - unsupervised training and ISOPRESS 2 - public health system), whether it works in patients with other cardiovascular diseases (ISOPRESS 3 - obstructive sleep apnea and ISOPRESS 4 - peripheral artery disease) and what are the mechanisms underlying the effects of isometric handgrip training in hypertensives (ISOPRESS 5 - neural mechanism). The study will yield information on the effectiveness of isometric handgrip training in different settings and patients with other cardiovascular diseases. Finally, it will help to understand the mechanisms involved in reducing blood pressure in hypertensives.(AU)