RESUMO Um conjunto de estudos que tem analisado o efeito de diferentes métodos de treinamento resistido na hipertrofia muscular. Estudos têm pontuado várias potenciais vantagens do treinamento usando séries em conglomerados (SC) quando comparado com séries tradicionais. Ainda não está claro se as SC é um método efetivo. O objetivo desta revisão foi investigar e discutir o conhecimento recente sobre o efeito das SC na hipertrofia muscular. Quatro estudos investigando o efeito das SC na hipertrofia muscular foram encontrados. Esses estudos demonstraram que as SC induziram similar ou menor hipertrofia muscular do que séries tradicionais. Portanto, as SC podem induzir hipertrofia, porém não fornecem um estímulo superior quando comparado às séries tradicionais com carga equiparada.

ABSTRACT There are a plethora of studies that have analyzed the effects of different resistance training methods on muscle hypertrophy. Recent studies have pointed out some potential advantage of training using cluster sets (CS) compared with traditional sets. It is still unclear whether CS are an effective method. The objective of this review was to investigate and discuss the current knowledge about the effect of CS on muscle hypertrophy. Four studies investigating the effect of CS on muscle hypertrophy were found. These studies demonstrated that CS induced similar or lower muscle hypertrophy than traditional sets. Thus, CS may lead to muscle hypertrophy, but did not provide a superior stimulus when compared to traditional sets of equated load.

RESUMEN Muchos estudios han analizado los efectos de diferentes métodos de entrenamiento de la fuerza en la hipertrofia muscular. Algunos estudios han resaltado las ventajas de introducir períodos de recuperación intra-serie (series cluster, SC) al compararlo con las series tradicionales. No está todavía claro si las SC son un método efectivo. El objetivo de esta revisión fue investigar y discutir el conocimiento actual sobre el efecto de las SC en la hipertrofia muscular. Se encontraron cuatro estudios investigando el efecto de las SC en la hipertrofia. Estos estudios demuestran que las SC inducen igual o menor hipertrofia que las series tradicionales. Así, las SC podrían inducir hipertrofia muscular pero no proporcionan un estímulo superior al compararlas con las series tradicionales.

Resumo Um protocolo específico de Drop Jumps (DJs), com 100 saltos, tem sido amplamente utilizado para induzir o dano muscular. Entretanto, este protocolo tem falhado em mostrar uma queda relevante em indivíduos treinados. Objetivou-se avaliar o desempenho muscular após dois protocolos de DJs com diferentes volumes em indivíduos treinados. Dezoito homens treinados em força e/ou potência (4,92 ± 2,78 anos de treinamento) foram aleatoriamente designados em um dos dois grupos: DJ100 (cinco séries de 20 DJs) ou DJ140 (sete séries de 20 DJs), com 2 minutos entre as séries. Os DJs foram executados de uma caixa de 60 cm de altura. Após a aterrisagem, os voluntários executaram um salto vertical máximo. O inchaço muscular aumentou significativamente em ambos os grupos (p < 0,001). O torque isométrico máximo (TIM) reduziu significativamente tanto no DJ100 (p = 0,005) quanto no DJ140 (p < 0,001). O TIM não apresentou diferenças entre grupos no momento pré (p = 0,815). Entretanto, no momento pós, o TIM foi significativamente inferior no DJ140 em relação ao DJ100 (p = 0,043). O salto com contra movimento (SCM) reduziu significativamente no DJ140 (p = 0,001), mas não no DJ100 (p = 0,802). No momento pós, o SCM foi significativamente inferior no DJ140 em relação ao DJ100. O DJ140 induziu uma queda maior na força isométrica em relação do DJ100, e somente o DJ140 reduziu significativamente o desempenho no salto. Esses resultados demonstraram que indivíduos bem treinados requerem um grande volume DJs para reduzir substancialmente o desempenho muscular.

Abstract A specific drop jumps (DJs) protocol (using 100 jumps) has been largely used to induce muscle damage. However, it failed to show relevant drop in performance in well-trained individuals. Trained subjects may require a protocol with greater volume to induce decrease of muscle performance. The aim of this study was to assess muscle performance after two DJs damaging protocols with different volumes in well-trained individuals. Eighteen strength and/or power-trained males (4.92 ± 2.78 years of training experience) were randomly assigned into one of two groups: DJ100 (five sets of 20 DJs) or DJ140 (seven sets of 20 DJs), with 2-min of rest interval. DJs were performed from a 60-cm box. After landing, the volunteers performed a maximal vertical rebound jump. Muscle swelling increased significantly on both DJ100 and DJ140 (p < 0.001). Maximal isometric torque (MIT) decreased significantly on both DJ100 (p = 0.005) and DJ140 (p < 0.001). MIT showed no between-group difference on pre-assessment (p = 0.815). However, on post-assessment, MIT was significantly lower on DJ140 than DJ100 (p = 0.043). Countermovement jump (CMJ) decreased significantly on DJ140 (p = 0.001), but not on DJ100 (p = 0.802). There was no between-group difference on pre-assessment (p = 0.978). However, on post-assessment, CMJ was significantly lower on DJ140 than DJ100 (p = 0.038). DJ140 induced greater drop in isometric strength than DJ100 and only DJ140 significantly reduced jump performance. These results demonstrated that well-trained individuals require a great volume of DJs to reduce substantially muscle performance.

ABSTRACT Background Different ultrasound parameters have been frequently used to assess changes associated with training, aging, immobilization, and neuromuscular diseases. However, an exploratory reliability analysis of the echo intensity (EI) and muscle thickness (MT) of the forearm flexors is scarce, especially in women. Objective The purpose of the present study was to determine the intra-rater reliability of MT and EI assessed by ultrasound in young women. Method Ultrasonographic MT and EI were acquired in the forearm flexors of 41 young women (22±2 yrs). Reliability was calculated using intraclass correlation coefficient (ICC2,1), standard error of measurement (SEM), coefficient of variation (CV), smallest detectable change (SDC), and Bland and Altman plot analysis. Results ICC values for MT and EI were 0.88 (95% CI: 0.78-0.93). The SEM and CV values were lower than 10%. Bland and Altman analysis revealed that ultrasound mean differences were 0.27 mm (Limits of Agreement - LOA 95%: - 2.6 to 3.2 mm) and -0.09 a.u. (LOA 95%: - 10.9 to 10.7 a.u.). Conclusion MT and EI assessed by ultrasonography in young women appear to be reliable and may be used to monitor changes in muscle mass induced by strength training when these changes exceed the precision of ultrasound.

BACKGROUND: Subcutaneous adipose tissue may influence the transmission of electrical stimuli through to the skin, thus affecting both evoked torque and comfort perception associated with neuromuscular electrical stimulation (NMES). This could seriously affect the effectiveness of NMES for either rehabilitation or sports purposes. OBJECTIVE: To investigate the effects of skinfold thickness (SFT) on maximal NMES current intensity, NMES-evoked torque, and NMES-induced discomfort. METHOD: First, we compared NMES current intensity, NMES-induced discomfort, and NMES-evoked torque between two subgroups of subjects with thicker (n=10; 20.7 mm) vs. thinner (n=10; 29.4 mm) SFT. Second, we correlated SFT to NMES current intensity, NMES-induced discomfort, and NMES-evoked knee extension torque in 20 healthy women. The NMES-evoked torque was normalized to the maximal voluntary contraction (MVC) torque. The discomfort induced by NMES was assessed with a visual analog scale (VAS). RESULTS: NMES-evoked torque was 27.5% lower in subjects with thicker SFT (p=0.01) while maximal current intensity was 24.2% lower in subjects with thinner SFT (p=0.01). A positive correlation was found between current intensity and SFT (r=0.540, p=0.017). A negative correlation was found between NMES-evoked torque and SFT (r=-0.563, p=0.012). No significant correlation was observed between discomfort scores and SFT (rs=0.15, p=0.53). CONCLUSION: These results suggest that the amount of subcutaneous adipose tissue (as reflected by skinfold thickness) affected NMES current intensity and NMES-evoked torque, but had no effect on discomfort perception. Our findings may help physical therapists to better understand the impact of SFT on NMES and to design more rational stimulation strategies.

O objetivo do presente estudo foi analisar as respostas de pressão arterial sistólica (PAS) e pressão arterial diastólica (PAD) após três sessões experimentais: exercício de força (EF), exercício combinado (COMB-aeróbio e EF) e controle sem exercício (CON). Trinta mulheres com síndrome metabólica (SM) foram randomicamente alocadas a uma das três sessões experimentais: EF (n=10; 36,1 ± 9,0 anos) (3 séries de 8-12 repetições a 80% de 10RM em 6 exercícios para o corpo todo); COMB (n=10; 33,1 ± 5,0 anos) (30 min de exercício aeróbio a 65-70% da frequência cardíaca de reserva, sucedido da mesma sessão de EF) e CON (n=10; 30,4 ± 6,6 anos). A PAS e PAD foram medidas antes e a cada 15 min, nos 60 min subsequentes às sessões experimentais. O grupo COMB apresentou maior diminuição do delta da PAS (ΔPAS), nos momentos 15, 30 e 45 min pós-exercício, quando comparado ao grupo CON (p <0,05); o grupo EF apresentou maior redução ΔPAS (p < 0,05), nos momentos 30 e 45 minutos pós-exercício, também comparado ao grupo CON. Adicionalmente, a área abaixo da curva do ΔPAS para os grupos COMB (~30 mmHg de hipotensão em 60 min, p ≤ 0,0005) e EF (~19 mmHg de hipotensão em 60 min, p = 0,024) foram maiores em relação ao grupo CON. Portanto, tanto o EF como o COMB induziram hipotensão pós-exercício em mulheres com SM, com maior magnitude para o grupo COMB, o que pode ser interessante para prevenção e tratamento de problemas cardiovasculares.

The aim of the present study was to analyze the response of systolic (SBP) and diastolic (DBP) blood following three experimental sessions: resistance exercise (RE), combined exercise (COMB-aerobic and RE) and control session (CON). Thirty women with metabolic syndrome (MS) were randomly assigned to one of three experimental groups: RE (n=10; 36.1 ± 9.0 years) (3 sets of 8-12 repetitions at 80% of 10RM in six exercises for whole body); COMB (n=10; 33.1 ± 5.0 years) (30 min of aerobic exercise at 65-70% of reserve heart rate which was followed by the same RE session) and CON (n=10; 30.4 ± 6.6 years). The SBP and DBP were measured before and every 15 min during 60 min following the experimental sessions. The COMB group presented greater delta SBP (ΔSBP) decrease at 15, 30 and 45 min post-exercise as compared with CON group (p <0.05); the RE group presented greater ΔSBP reduction at 30 and 45 min post-exercise also compared with CON group (p <0.05). In addition, the area under the curve of ΔSBP for COMB group (~30 mmHg of hypotension during 60 min, p ≤ 0.0005) and RE group (~19 mmHg of hypotension during 60 min, p = 0.024) were greater than the CON group. Therefore, RE and COMB elicited post-exercise hypotension in women with MS; COMB provided a greater decrease which may be of value in the prevention and treatment of cardiovascular disorders.

CONTEXTUALIZAÇÃO:Estudos demonstraram que a pré-ativação de músculos antagonistas pode aumentar o desempenho neuromuscular agonista. Além disso, estudos sugerem que programas de exercício resistido (ER) de curta duração podem ser úteis para aumentar a força muscular e o desempenho. OBJETIVOS: Avaliar os efeitos de três sessões de ER por meio do método de ações recíprocas no desempenho muscular de homens sadios e comparar com um grupo de ER tradicional. MÉTODO: Trinta e três homens (21,1 ± 2,3 anos) foram randomicamente alocados em três grupos: Recíproco (REC: uma repetição de flexão do joelho imediatamente seguida por uma de extensão do joelho); Tradicional (TRA: exercício concêntrico de extensão do joelho) e Controle (CON: não realizaram exercício). O REC e o TRA realizaram quatro séries de dez repetições a 60º.s-1 com um minuto entre séries. As avaliações pré e pós-ER foram caracterizadas por duas séries de quatro repetições máximas a 60º.s-1 e 180º.s-1. Utilizou-se ANOVA 3x2, com post-hoc de Tukey para verificar diferenças no pico de torque (PT), taxa de desenvolvimento de aceleração (TDA) e tempo para atingir o PT (TEMPtorque). RESULTADOS: Houve um aumento do PT para o REC e o TRA (p<0.05) a 60º.s-1 e apenas para o REC a 180º.s-1 (p<0,05). Houve diminuição da TDA para o REC e o TRA (p<0,05) e, apenas no REC, o TEMPtorqueapresentou quedas significantes. A análise intergrupos mostrou que o REC foi mais efetivo que o TRA para os ganhos de PT em ambas as velocidades (p<0,05). CONCLUSÃO: Sugere-se que a modalidade recíproca seja vantajosa para a prática de profissionais envolvidos no processo de reabilitação neuromuscular.

BACKGROUND: Previous studies have shown that preloading an antagonist muscle may increase the acute agonist neuromuscular performance. In addition, studies have suggested that very short-term resistance exercise (RE) programs may also be useful to increase strength and muscular performance. OBJECTIVES: To evaluate the effects of three days of RE using a reciprocal action method on the muscular performance of healthy men and to compare these effects with those of a traditional RE group.METHOD:Thirty-three men (21.1 ± 2.3 years) were randomly assigned to one of three groups: 1) reciprocal (REC; knee flexion immediately followed by a knee extension exercise); 2) traditional (TRA; non-preload; a concentric knee extension exercise); and 3) control (CON; no exercise). The REC and TRA subjects performed four sets of 10 repetitions at 60º/s with one minute of rest. The pre- and post-RE tests included two sets of four maximal concentric repetitions at 60º/s and 180º/s. A 3x2 ANOVA with Tukey post-hoc was used to analyze the differences in peak torque (PT), rating of acceleration development (RAD) and time to peak torque (TIMEtorque). RESULTS: A significant PT increase was found for REC and TRA (p<0.05) at 60º/s and for REC at 180º/s (p<0.05). There was a decrease in the RAD for REC and TRA (p<0.05), and TIMEtorque showed a significant decrease for REC. The inter-group analysis revealed that REC is more effective than TRA for PT gains at both velocities (p<0.05). CONCLUSION:It is recommended that REC offers benefits for the clinical practice of professionals involved in neuromuscular rehabilitation.