Manipulating Resistance Training Variables to Induce Muscle Strength and Hypertrophy: A Brief Narrative Review.

The regular practice of resistance training (RT) has been shown to induce relevant increases in both muscle strength and size. In order to maximize these adaptations, the proper manipulation of RT variables is warranted. In this sense, the aim of the present study was to review the available literature that has examined the application of the acute training variables and their influence on strength and morphological adaptations of healthy young adults. The information presented in this study may represent a relevant approach to proper training design. Therefore, strength and conditioning coaches may acquire a fundamental understanding of RT-variables and the relevance of their practical application within exercise prescription.

Nível de aptidão física de escolares da rede pública e privada da região de Leme-Sp / Level of physical fitness of children from public and private schools in the region of Leme-Sp

A aptidão física se relaciona com marcadores de saúde na infância. O objetivo do presente estudo é mensurar os níveis de aptidão física de escolares, de 10 anos, de acordo com as classificações da base de dados do Projeto Esporte Brasil, 2016 e comparar os resultados das avaliações entre os escolares da rede pública e privada. Participaram desse estudo cento e vinte e seis escolares das cidades de Leme e Pirassununga. Foram determinados o Índice de Massa Corporal e Razão Cintura-Estatura dos indivíduos, que também foram avaliados quanto à aptidão cardiorrespiratória, flexibilidade, resistência muscular abdominal, potência de membros superiores, potência de membros inferiores, agilidade e velocidade. Concluímos que os estudantes da rede pública de ensino apresentaram nível de aptidão física superior em detrimento aos estudantes da rede particular e que os estudantes do sexo masculino da rede privada obtiveram resultados considerados abaixo dos níveis saudáveis para a faixa etária.

Physical fitness is related to health markers in childhood. The aim of this study is to measure the physical fitness levels of 10-year-old schoolchildren according to the classifications in the 2016 Projeto Esporte Brasil database and to compare the results among public and private schoolchildren. One hundred and twenty-six schoolchildren from the cities of Leme and Pirassununga took part in this study. The Body Mass Index and Waist-to-Height Ratio of the individuals were determined. The children were also evaluated for cardiorespiratory fitness, flexibility, abdominal muscle resistance, upper limb power, lower limb power, agility, and speed. It could be concluded that students from the public school system presented a higher level of physical fitness when compared to those from the private system, and that male students from the private school system presented results which were considered below the healthy levels for that age group.

Posttraumatic stress disorder among adolescents in Brazil: a cross-sectional study.

BACKGROUND: The frequency of trauma and different types of violence exposure in urban areas and their effects on the mental health of adolescents in developing countries are poorly investigated. Most information about traumatized young people comes from war scenarios or disasters. This study aimed to determine the prevalence of PTSD in trauma-exposed students in a low-resource city of the state of Rio de Janeiro, Brazil. The effects of sociodemographic and individual and family factors in the development of PTSD were also investigated. METHODS: Through multi-stage cluster sampling, 862 adolescents (Mage = 15 years old, 65% female) from public and private schools in the city of São Gonçalo were selected for the study. Self-rating structured questionnaires were applied to assess sociodemographic profile, exposure to physical and psychological violence (family, school, community), sexual abuse, social support, social functional impairment, resilience, and posttraumatic stress disorder. The data were grouped in blocks regarding sociodemographic, individual, family, and community variables. For statistical analysis, chi-square, Fisher's exact test, and logistic regression were performed. RESULTS: The PTSD prevalence was 7.8% among adolescents. Boys were exposed to significantly higher number of events of community violence, while girls to family violence. The adjusted odds ratio (OR) for PTSD were statistically significant for age (OR, 1.45, [95% CI, 1.043-2.007]), social functional impairment (OR, 4.82, [95% CI, 1.77-13.10]), severe maternal physical violence (OR, 2.79, [95% CI, 0.79-9.93]), psychological violence by significant people (OR, 3.96, [95% CI, 1.89-8.31]) and a high number of episodes of community violence (OR, 3.52, [95% CI, 1.47-8.40). CONCLUSIONS: There was a high prevalence of PTSD within this population associated with exposure to violence. Not only physical, but also psychological violence contributed to PTSD. The results also raise awareness to the differences in life trajectories between boys and girls regarding violence. These differences need to be better understood in order to enable the development of effective preventative interventions. Treating and preventing mental health disorders presents a challenge for countries, especially those with a lower degree of social and economic development and high community violence.

A imunização de crianças no Brasil: Panorama jurídico e reflexão bioética / La inmunización de niños en Brasil: Panorama jurídico y reflexión bioética / The immunization of children in Brazil: Legal overview and bioethical análysis / La immunització de nens al Brasil: Panorama jurídic i reflexió bioètica

O objetivo deste artigo é analisar os aspectos jurídicos e bioéticos da vacinação obrigatória de crianças brasileiras. Primeiro, apresentamos a vacinação como um dever decorrente do direito fundamental à saúde de crianças. Depois, realiza-se uma discussão bioética sobre o citado dever jurídico, abordando os principais problemas bioéticos envolvendo a vacinação, com destaque para os eventos adversos pós-vacinação. Concluímos que a Bioética não se propõe a estabelecer normas coercitivas, mas que ela contribui para a solução dos conflitos morais identificados em cada caso concreto ao oferecer parâmetros. Já o direito brasileiro busca assegurar o direito à saúde em sua dimensão coletiva ao estabelecer a obrigatoriedade da imunização para as crianças

El objetivo de este artículo es analizar los aspectos jurídicos y bioéticos de la vacunación de niños brasileños. En primer lugar, presentamos la vacunación como un deber derivado del derecho fundamental a la salud de los niños. Después, se realiza una discusión bioética sobre el citado deber jurídico, abordando los principales problemas bioéticos involucrando la vacunación, destacando los eventos adversos post-vacunación. Concluimos que la Bioética no se propone a establecer normas coercitivas, sino que contribuye a la solución de los conflictos morales identificados en cada caso concreto al ofrecer parámetros. El derecho brasileño busca asegurar el derecho a la salud en su dimensión colectiva al establecer la obligatoriedad de la inmunización para los niños

The objective of this article is to analyze the legal and bioethical aspects of mandatory vaccination of Brazilian children. First, we present vaccination as a duty arising from fundamental right to health of children. Afterwards, it makes a bioethical discussion about the legal duty of children's vaccination, addressing the main bioethical problems involving vaccination, especially the postvaccination adverse events. We conclude that Bioethics does not propose to establish coercive norms, but that it contributes to the solution of the moral conflicts identified in each concrete case by offering parameters. Brazilian law seeks to ensure the right to health in its collective dimension when establishing the mandatory immunization for children

L'objectiu d'aquest article és analitzar els aspectes jurídics i bioètics de la vacunació de nens brasilers. En primer lloc, presentem la vacunació com un deure derivat del dret fonamental a la salut dels nens. Després, es realitza una discussió bioètica sobre el citat deure jurídic, abordant els principals problemes bioètics involucrant la vacunació, destacant els esdeveniments adversos post-vacunació. Concloem que la Bioètica no es proposa a establir normes coercitives, sinó que contribueix a la solució dels conflictes morals identificats en cada cas concret en oferir paràmetres. El dret brasiler busca assegurar el dret a la salut en la seva dimensió col·lectiva en establir l'obligatorietat de la immunització per als nens

Effect of downhill walking training on neuromuscular variables / Efeito do treinamento de caminhada no declive em variáveis neuromusculares

Abstract Walking involves small adjustments to maintain body balance. However, thedemand for these adjustments may be different during downhill walking. The aim of this study was to analyze the effect of periodized downhill walking training on neuromuscular responses of knee flexors (KF). Seventeen active males (Age = 22.9 ± 3.9 years) were randomly assigned into two groups: control, level walking (CG, N = 8) and downhill walking (DWG, N = 9). Individuals performed the following procedures, in different days: 1) Maximal voluntary contractions to determine peak torque (PT) and rate of torque development (RTD) at different time intervals from the onset of muscle contraction. The test was performed before (Pre) and after (Post) a 4-week downhill walking training period. PT and peak RTD did not change after the training period (p > 0.05). However, there was significant increase in RTD at 150 ms and 200 ms after the onset of muscle contraction (p < 0.05). Additionally, the electromyographic activity (root mean square) of the biceps femoris and semitendineous muscles presented an increase after the training period (p < 0.05). Thus, downhill walking training can promote improvement RTD and muscle activity in the late phase of muscle contraction, which can have important implications during downhill walking, in which a rapid action of KF can help body balance against the disturbance generated by the slope.

Resumo O ato de caminhar envolve pequenos ajustes para manutenção do equilíbrio corporal. No entanto, a demanda por estes ajustes pode ser diferente na caminhada no declive. O objetivo deste estudo foi analisar o efeito do treinamento periodizado de caminhada em declive na resposta neuromuscular dos músculos flexores do joelho (KF). Dezessete indivíduos ativos do gênero masculino (Idade = 22,9 ± 3,9 anos) foram divididos randomicamente em dois grupos: controle, com caminhada no plano (CG, n = 8), e caminhada em declive (DWG, n = 9). Os indivíduos realizaram os seguintes procedimentos, em diferentes dias: 1) Contrações voluntárias máximas para determinar o pico de torque (PT) e a taxa de desenvolvimento de torque (RTD) em diferentes intervalos de tempo após o início da contração. Os testes foram realizados antes (Pré) e após (Pós) um período de quatro semanas de treinamento de caminhada em declive. O PT e a RTD pico não apresentaram mudança após o período de treinamento (p < 0,05). No entanto, houve aumento significante na RTD nos momentos 150 e 200 ms para o grupo DWG (p < 0,05). Além disso, a atividade eletromiográfica (root mean square) do músculo bíceps femoral e do semitendinoso apresentou aumento após o período de treinamento (p < 0,05). Portanto, o treinamento de caminhada em declive pode promover aumento na RTD em sua fase tardia e na ativação muscular, o que pode ter implicações em condições de caminhada no declive, que podem auxiliar a estabilizar o corpo contra a perturbação gerada pelo declive.

Effects of downhill walking training on aerobic and neuromuscular fitness of young adults / Efeitos da caminhada em declive na aptidão aeróbia e neuromuscular em adultos jovens

Abstract Eccentric exercise training using low intensity-high volume approach has been performed to improve maximal muscle strength and power. The aim of this study was to compare the effects of short-term downhill walking and level walking training on lower limb strength and maximal oxygen uptake of active individuals. Eighteen young adults were divided into level walking group (n = 9) or downhill walking training group (n = 9). Both groups performed a four-week training program. The level walking group performed seven level walking sessions per week, while the downhill walking group walked downhill (-16%) in the same weekly frequency. One week before and one week after the training protocol, maximal oxygen uptake, muscle-bone cross-sectional area and isometric peak torque of knee extensors and plantar flexors were assessed for both groups. A significant group vs. time interaction was found only for cross sectional area of plantar flexors (PF), showing increases for the downhill walking group (112.6 ± 28.9 cm2 vs. 115.9 ± 29 cm2) but not for the level walking group (94.9 ± 23.3 cm2vs. 94.6 ± 228 cm2). Maximal oxygen uptake remained unaltered after training for both groups and IPT was increased after training for both groups. It was concluded that short-term downhill walking training does not seem to be efficient in promoting improvements in cardiorrespiratory fitness of young adults. However, it seems to promote gains in some variables related to neuromuscular fitness.

Resumo O treinamento excêntrico de baixa intensidade e alto volume vem sendo adotado para desenvolver a força e a potência muscular. O objetivo deste estudo foi comparar os efeitos do treinamento de caminhada em declive e em plano, em parâmetros de força de membros inferiores e consumo máximo de oxigênio de indivíduos ativos. Dezoito adultos foram separados em grupos de treinamento em plano (GTP - n = 9) em declive (GTD - n = 9). Ambos realizaram um programa de treinamento de 4 semanas. O GTP realizou sete sessões semanais de caminhada no plano, enquanto o GTD caminhou em declive (-16%). Uma semana antes e uma semana após o treinamento, foram medidos o consumo máximo de oxigênio, área de secção transversa músculo-óssea e o pico de torque isométrico dos extensores do joelho e flexores plantares dos participantes. Interação significante grupo-tempo foi identificada apenas para a área de secção transversa dos flexores plantares, demonstrando aumentos para o grupo GTD (112,6 ± 28,9 cm2vs. 115,9 ± 29 cm2), mas não para o GTP (94,9 ± 23,3 cm2vs. 94,6 ± 228 cm2). O consumo máximo de oxigênio permaneceu inalterado após o treinamento para ambos os grupos e o pico de torque isométrico aumentou significantemente após o treinamento para ambos os grupos. Concluímos, então, que um treinamento de caminhada em declive de curto prazo parece não ser eficiente na promoção de melhoras significativas de parâmetros cardiorrespiratórios de adultos jovens, embora seja efetivo no incremento de algumas variáveis relacionadas à aptidão neuromuscular.

Postactivation potentiation biases maximal isometric strength assessment.

Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n = 23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·m versus 248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s(-1) versus 727 ± 158 N·m·s(-1)), and RMS (59.1 ± 12.2% RMSMAX versus 54.8 ± 9.4% RMSMAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 ms versus 2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables.

Monitoramento de marcadores de dano muscular durante um programa de quatro semanas de treinamento de caminhada em declive / Marcadores de monitoreo de daño muscular durante un programa de cuatro semanas de entrenamiento a pie cuesta abajo / Monitoring muscle damage markers during a four-week downhill walking exercise program

Eccentric-based exercise is known to induce muscle damage (MD). The purpose of this study was to investigate effect of downhill walking (DW) sessions on MD and aerobic markers in young adults. Eight male subjects were submitted to a 4-week DW periodized exercise program. Subjects' soreness (SOR) was assessed each training day. Serum creatine quinase activity (CK) was collected before the first training session, and at the end of each of the four weeks. Oxygen uptake (VO2) and perceived exertion (PE) were assessed during the last training session every week. Increases in SOR were found only at the third and fourth training days. Increased CK concentration was found at the third training week. No significant increases in VO2 and PE were found throughout the program. We concluded that DW sessions elicit significant MD, but not enough to impair it in further sessions. Therefore, DW can be used as a training protocol following proper periodization.

Exercícios excêntricos costumam induzir dano muscular (DM). O objetivo deste estudo foi investigar respostas aeróbias e de DM a sessões de caminhada em declive (CaED) em adultos. Oito voluntários realizaram um programa periodizado de treinamento de CaED. A dor muscular (DMIT) foi coletada durante todos os dias de treinamento. A atividade sérica de creatina quinase (CK) foi coletada antes da primeira sessão e ao final das semanas 1-4. O consumo de oxigênio (VO2) e a percepção de esforço (PE) foram coletados durante a última sessão de treinamento de cada semana. Aumentos na DMIT foram identificados no terceiro e quarto dias de treinamento. Os valores de CK se apresentaram aumentados na terceira semana. Não foram identificadas diferenças nos valores obtidos de VO2 e PE. Concluímos que sessões de CaED induzem DM, porém este não afeta sessões posteriores. Portanto, a CaED pode ser utilizada como um método de treinamento, possibilitando sua periodização.

Ejercicio excéntrico desacostumbrado es conocido por inducir daño muscular (DM). El objetivo de este estudio fue investigar las respuestas a sesiones de caminar cuesta abajo (DW) en los adultos jóvenes, la evaluación de MD y los marcadores de aeróbicos. Ocho sujetos varones fueron sometidos a un programa de ejercicios de periodización de DW de 4 semanas. El dolor de los sujetos (SOR) se evaluó todos los días de entrenamiento. Actividad de la creatina quinasa sérica (CK) se recogió antes de la primera sesión de entrenamiento, y al final de las semanas 1-4. El consumo de oxígeno (VO2) y la percepción subjetiva del esfuerzo (PE) se evaluaron durante la última sesión de entrenamiento cada semana. Los aumentos en SOR se encontraron sólo en los tercero y cuarto día de entrenamiento. El aumento de la concentración de CK se encuentra en la tercera semana de entrenamiento. No hay un aumento significativo en el VO2 y PE se encuentran en todo el programa. Llegamos a la conclusión de que las sesiones DW provocan MD significativo, pero no lo suficiente como para poner en peligro otras sesiones. Por lo tanto, DW puede ser adoptado como método de entrenamiento, permitiendo periodización adecuada.