Blood flow restriction increases metabolic stress but decreases muscle activation during high-load resistance exercise.

INTRODUCTION: We investigated differences in metabolic stress (lactate) and muscle activation (electromyography; EMG) when high-load resistance exercise (HL) is compared with a condition in which blood flow restriction (BFR) is applied during the exercise or during the rest interval. METHODS: Twelve participants performed HL with BFR during the intervals (BFR-I), during the set (BFR-S), and without BFR. Each condition consisted of 3 sets of 8 repetitions with knee extension at 70% of 1-repetition maximum. Lactate and root mean square (RMS) from the surface EMG of the vastus lateralis were calculated. RESULTS: Lactate increased in all protocols but was higher with BFR-I than with BFR-S and HL. RMS decreased under all conditions, with a larger effect size in BFR-I (1.47) than in BFR-S (0.66) and HL (0.59). DISCUSSION: BFR-I increases lactate, possibly as a result of reduced restoration of ATP. Muscle activation seems to be impacted by mechanical stress but may be reduced by metabolic stress. Muscle Nerve 57: 107-111, 2018.

Previous participation in FIFA World-Cup: the key to success?

This qualitative-descriptive investigation examining the influence exerted by experienced soccer-players on the ranking obtained from the four best-ranked by their teams in the last four FIFA World Cups (WC). They were divided into experienced-players (at least one WC participation [+1WC]) or non-experienced players (no previous participation [1WC]). Thereafter, they were classified according to their contribution in each of the playoff matches in a given WC: STARTER (started all matches); START/SUBST (started at least one match); SUBST/BENCH (did not start any matches, but replaced a player in at least one match); and BENCH (did not participate in matches). The sample was composed of 33.7% experienced and 66.3% non-experienced players. The number of players +1WC in finalist teams was significantly higher than in the non-finalist teams (p<0.05). In addition, when compared with the non-finalist teams, the finalists presented significantly higher number of players STARTER with +1WC (p<0.05). Possibly, the selection of experienced players to participate in WC may be an effective strategy to achieve better competitive performance

Anthropometric parameters of cadets among different military sports / Parámetros antropométricos de cadetes entre los diferentes deportes militares

This study compared anthropometric parameters among different military sports. One hundred and seventy male cadets of the Brazilian Air Force Academy, who were participants of athletics (n= 33, 20.5±1.3 years), basketball (n= 11, 19.9±1.8 years), fencing (n= 10, 19.9±0.7 years), soccer (n= 21, 20.9±1.6 years), judo (n= 17, 20.7±1.0 years), swimming (n= 15, 20.4±1.2 years), orienteering (n= 10, 21.3±1.6 years), military pentathlon (n= 11, 20.7±1.2 years), water polo (n=10, 21.1±0.9 years), shooting (n= 18, 21.3±1.2 years) or volleyball (n= 14, 20.9±1.7 years) military competitive teams, participated in this study. Height, body mass, body mass index, fat percentage, lean body mass, fat mass, waist and hip perimeters, and waist-hip ratio were measured. Main effects were detected for height, body mass, body mass index, lean body mass, waist and hip perimeters. The only significant finding was that orienteers present lower lean body mass than volleyball and water polo players. These results point out the homogeneity of group anthropometric parameters (except lean body mass), suggesting that military coaches do not rely on the anthropometric parameters, but on specific skills demonstrated during initial period of practice to choose athletes for their teams.

Este estudio comparó los parámetros antropométricos entre cadetes que practican diferentes deportes militares. Ciento setenta cadetes hombres de la Academia de la Fuerza Aérea, que eran participantes de equipos militares competitivos de atletismo (n= 33, 20,5±1,3 años), baloncesto (n= 11, 19,9±1,8 años), esgrima (n= 10, 19,9±0,7 años), fútbol (n=21, 20,9±1,6 años), judo (n= 17, 20,7±1,0 años), natación (n= 15, 20,4±1,2 años), orientación (n= 10, 21,3±1,6 años), pentatlón militar (n= 11, 20,7±1,2 años), polo acuático (n= 10, 21,1±0,9 años), tiro (n= 18, 21,3±1,2 años) y voleibol (n= 14, 20,9±1,7 años) participaron en este estudio. Se midió la altura, masa corporal, índice de masa corporal, porcentaje de grasa corporal, masa magra, masa grasa, perímetros de cintura y cadera, y la relación cintura-cadera. No se detectaron variaciones de altura, masa corporal, índice de masa corporal, masa magra corporal, perímetro de cintura y cadera. El único hallazgo significativo fue que los orientadores tenían una masa corporal magra más baja que los jugadores de voléibol y polo acuático. Estos resultados apuntan a la homogeneidad de los parámetros antropométricos en grupos (excepto la masa magra), lo que sugiere que los instructores militares no dependen de los parámetros antropométricos, sino de las habilidades específicas demostradas durante el período de la práctica inicial en la selección de los atletas para sus equipos.

Creatine but not betaine supplementation increases muscle phosphorylcreatine content and strength performance.

We aimed to investigate the role of betaine supplementation on muscle phosphorylcreatine (PCr) content and strength performance in untrained subjects. Additionally, we compared the ergogenic and physiological responses to betaine versus creatine supplementation. Finally, we also tested the possible additive effects of creatine and betaine supplementation. This was a double-blind, randomized, placebo-controlled study. Subjects were assigned to receive betaine (BET; 2 g/day), creatine (CR; 20 g/day), betaine plus creatine (BET+CR; 2+20 g/day, respectively) or placebo (PL). At baseline and after 10 days of supplementation, we assessed muscle strength and power, muscle PCr content, and body composition. The CR and BET+CR groups presented greater increase in muscle PCr content than PL (p=0.004 and p=0.006, respectively). PCr content was comparable between BET versus PL (p=0.78) and CR versus BET+CR (p=0.99). CR and BET+CR presented greater muscle power output than PL in the squat exercise following supplementation (p=0.003 and p=0.041, respectively). Similarly, bench press average power was significantly greater for the CR-supplemented groups. CR and BET+CR groups also showed significant pre- to post-test increase in 1-RM squat and bench press (CR: p=0.027 and p<0.0001; BET+CR: p=0.03 and p<0.0001 for upper- and lower-body assessments, respectively) No significant differences for 1-RM strength and power were observed between BET versus PL and CR versus BET+CR. Body composition did not differ between the groups. In conclusion, we reported that betaine supplementation does not augment muscle PCr content. Furthermore, we showed that betaine supplementation combined or not with creatine supplementation does not affect strength and power performance in untrained subjects.

Efeito do número e intensidade das ações excêntricas nos indicadores de dano muscular / Effect of the number and the intensity of eccentric muscle actions on muscle damage markers

A realização de uma sessão de treinamento de força, especialmente de ações excêntricas, provoca danos à estrutura muscular. Algumas características da realização das ações excêntricas parecem agravar a ocorrência do dano. O número de contrações realizadas e o grau de tensão desenvolvida em cada uma delas parecem afetar a magnitude o dano. Dessa maneira, o objetivo deste estudo foi investigar se o número e a intensidade das ações excêntricas contribuem para o aumento do dano muscular, avaliado através das alterações de marcadores indiretos. Vinte e quatro jovens adultos do sexo masculino foram divididos aleatoriamente em três grupos. Um dos grupos realizou 30 ações excêntricas para os flexores do cotovelo com 70 por cento de 1RM (EXC30-70, n = 8). Outro grupo realizou o mesmo número de repetições, porém com 110 por cento de 1RM (EXC30110, n = 8). Um terceiro grupo realizou um número maior de repetições (60) com 70 por cento de 1RM (EXC60-70, n = 8). A amplitude de movimento, a circunferência do braço, a força máxima (1RM) e a dor muscular tardia foram avaliadas antes, imediatamente, 48 e 96 horas após o exercício. Os resultados foram analisados através de análise de variância com dois fatores e revelaram que as alterações foram maiores no grupo EXC30-110 comparadas com EXC30-70 e EXC60-70. Esses dados sugerem que a intensidade das ações excêntricas afeta mais a ocorrência de dano do que o número de contrações.

A single bout of resistance training, especially with eccentric actions, induces damage to the muscle structure. Characteristics of eccentric actions may increase muscle damage. The number and intensity of contractions seem to affect the magnitude of muscle damage. Thus, the aim of this study was to investigate if the number and the intensity of contraction increase muscle damage, evaluated through alterations in indirect markers of muscle damage. Twenty-four young male adults were randomly placed into three groups. One of the groups performed 30 eccentric actions of the elbow flexors at 70 percent of 1RM (EXC30-70, n = 8). Another group performed the same number of repetitions, but at 110 percent of 1RM (EXC30-110, n = 8). A third group performed a higher number of repetitions (60) at 70 percent of 1RM (EXC60-70, n = 8). Range of motion, limb girth, maximal dynamic strength (1RM) and muscle soreness were assessed before, immediately after, 48h and 96h post exercise. Results were analyzed by a 2-way ANOVA and showed that alterations were more remarkable larger in EXC30-110 compared to EXC30-70 and EXC60-70. These data suggest that eccentric action intensity affects the magnitude of muscle damage more than the number of contractions.

Influence of strength training background on postactivation potentiation response.

The aim of this study was to evaluate the influence of the subjects' level of maximal dynamic strength and training background on postactivation potentiation (PAP). A group of 23 subjects, composed of power track-and-field athletes (PT = 8), bodybuilders (BB = 7), and physically active subjects (PA = 8), participated in the study. Maximal dynamic strength (1 repetition maximum test) was assessed in the leg press exercise for subjects' characterization. Their countermovement vertical jump (CMJ) performance was assessed before and after 2 different conditioning activity (CA) protocols (1 or 3 maximum voluntary isometric contractions [MVICs] of 5-second duration in the leg press exercise) or after control (no CA), performed on separate days. No significant differences among groups were found for CMJ height or take-off velocity after any of the CA protocols (p ≤ 0.05). However, individual analysis showed that some subjects increased performance in response to the CA, despite their previous training history. We concluded that subjects' level of maximal dynamic strength and training background have no influence on PAP manifestation. Our data suggest that coaches should individually identify the athletes that are PAP responders before introducing MVICs as part of their warm-up routines.

Effect of eccentric exercise velocity on akt/mtor/p70(s6k) signaling in human skeletal muscle.

It has been suggested that muscle tension plays a major role in the activation of intracellular pathways for skeletal muscle hypertrophy via an increase in mechano growth factor (MGF) and other downstream targets. Eccentric exercise (EE) imposes a greater amount of tension on the active muscle. In particular, high-speed EE seems to exert an additional effect on muscle tension and, thus, on muscle hypertrophy. However, little is known about the effect of EE velocity on hypertrophy signaling. This study investigated the effect of acute EE-velocity manipulation on the Akt/mTORCI/p70(S6K) hypertrophy pathway. Twenty subjects were assigned to either a slow (20°·s(-1); ES) or fast EE (210°·s(-1); EF) group. Biopsies were taken from vastus lateralis at baseline (B), immediately after (T1), and 2 h after (T2) the completion of 5 sets of 8 repetitions of eccentric knee extensions. Akt, mTOR, and p70(S6K) total protein were similar between groups, and did not change postintervention. Further, Akt and p70(S6K) protein phosphorylation were higher at T2 than at B for ES and EF. MGF messenger RNA was similar between groups, and only significantly higher at T2 than at B in ES. The acute manipulation of EE velocity does not seem to differently influence intracellular hypertrophy signaling through the Akt/mTORCI/p70S6K pathway.

Número de repetições e intensidade relativa em membros superiores e inferiores: implicações para o treinamento / Number of repetitions and relative intensity in upper and lower limbs: implications to training

Tradicionalmente, as recomendações para a prescrição do treinamento de força podem ser baseadas tanto na intensidade relativa ao 1RM quanto no número de repetições máximas. Entretanto, sabe se que o número máximo de repetições realizadas com a mesma carga relativa varia de acordo com o exercício e o tamanho do grupo muscular envolvido. Além disso, considerando tal diferença nas respostas musculares a diferentes cargas, é possível especular que o número máximo de repetições em cada série de exercício em uma sessão tradicional de treinamento de força (com múltiplas séries) pode também ser diferentemente afetado ao compararmos os membros superiores e superiores. Isto se torna particularmente importante, ao considerarmos as sugestões recentes de que o número total de repetições realizadas em um treinamento de força pode afetar as adaptações oriundas do mesmo. Assim, o presente trabalho teve o objetivo de comparar o número de repetições realizadas com uma mesma intensidade relativa tradicionalmente recomendada para hipertrofia muscular em séries múltiplas de exercícios para os membros superiores e inferiores. Doze homens jovens treinados foram testados para força dinâmica máxima (1RM) nos exercícios leg-press e supino reto. Uma semana depois, os participantes realizaram três séries até a falha concêntrica com carga igual a 80% de 1RM com dois minutos de intervalo entre séries. O número máximo de repetições realizadas em cada série foi anotado e utilizado para análise estatística. A análise por modelos mistos revelou que o número de repetições realizadas no leg-press foi maior do que no supino reto (p<0,05). Além disso, o número de repetições diminui ao longo das três séries sem diferença entre os exercícios. Assim, é possível sugerir que as recomendações para o treino de força que visa hipertrofia devem ser revistas e possivelmente incluir recomendações diferenciadas para exercícios distintos.

Traditionally, the recommendations to resistance training prescription are based on the relative intensity or on the number of repetition maximum. However, it is well known that the maximal number of repetitions performed with the same relative intensity varies according to both the exercise and the muscle size. Besides, considering the different muscle response to different loads, it is plausible to speculate that the maximal number of repetitions performed in each set of a traditional bout of resistance exercise (multiple-set scenario) may also differ between upper- and lower-limbs. This is of particular interest if we take into account the recent suggestions that the total number of repetitions may play an important role in the adaptations to strength training. Hence, the aim of this study was to compare the number of repetitions performed in multiple sets of exercises performed with the traditionally recommended hypertrophy-oriented intensity in upper- and lower-limb exercises. Twelve trained male adults were tested for one repetition maximum (1RM) in the leg-press and bench press exercises. After one week, participants performed three sets to concentric failure with 80% 1RM with 2-min interval between sets. The maximal number of repetition was recorded and used for statistical analyses. Mixed model analyses showed that number of repetitions performed on the leg-press was higher than on the bench press (p<0.05). In addition, the number of repetitions decreased similarly in both exercises along the three sets. Therefore, it is possible to suggest that hypertrophy oriented resistance training recommendation should be revised, and possibly include distinct recommendation to different exercises.

Efeito da ordem dos exercícios no número de repetições e na percepção subjetiva de esforço em homens treinados em força / The effect of the exercises order on number of repetitions and rate of perceived effort in resistance trained men

A ordem dos exercícios refere-se à sequência de execução durante uma sessão de treinamento. Evidências demonstram que essa ordem pode afetar o número de repetições realizadas nos exercícios. A percepção subjetiva de esforço (PSE), assim como o número de repetições realizadas, depende da sobrecarga utilizada. Assim, alterações no número de repetições podem afetar a PSE. O volume total de trabalho (VTT) influencia nas adaptações crônicas ao treinamento e também pode ser afetado pela ordem dos exercícios. O objetivo foi verificar o efeito da ordem dos exercícios para membros inferiores no número de repetições realizadas, na PSE e no VTT. Doze homens treinados (19,3 ± 2,1 anos, 71,1 ± 9,8 kg, 172,4 ± 6,1 cm, 23,3 ± 11,5 meses/treino) realizaram duas sessões com os exercícios "leg-press" (L), mesa flexora (F) e cadeira extensora (E) em diferentes ordens (LFE ou EFL). Foram utilizados testes t de "Student" pareados com ajuste de Bonferroni para comparações múltiplas. O número de repetições em L e E diminuiu quando realizados no final da sessão. As repetições realizadas em F diminuíram na LFE. A PSE de E foi maior quando realizada no final da sessão, porém de L e de F não foram afetadas pelas diferentes ordens. O volume de trabalho total de LFE foi maior. Em conclusão, a ordem dos exercícios envolvendo membros inferiores afeta o número de repetições e a PSE de um exercício além do VTT, ressaltando a importância da ordem dos exercícios como uma importante variável na prescrição do treinamento.

The order of exercises refers to the sequence during a training bout. Some evidence shows that the number of repetitions may be affected by the order of exercises. Both the number of repetitions and the rate of perceived effort (PSE) are influenced by exercise load. Thus, changes in the number of repetitions may affect PSE. Additionally, total work volume influences long term training adaptations and can be affected by the order of exercises. The aim of this study was to evaluate the effect of order of lower limb exercises on the number of repetitions, RPE and total work volume. Twelve resistance trained male (19.3 ± 2.1 years, 71.1 ± 9.8 kg, 172.4 ± 6.1 cm, 23.3 ± 11.5 months of training) performed leg-press (L), leg extension (E) and leg curl (F) exercises, in different orders (LFE or EFL). Number of repetitions, PSE and total work volume were compared by paired t-test with Bonferroni adjustment. Number of repetitions on both L and E decreased when they were performed last in the bout. The number of repetitions on F also decreased, when F was preceded by L. PSE for E was greater when performed at the end of the bout. However, PSE after L and F were not affected by the order. Total work volume was greater in LFE. In conclusion, the order of lower limb exercises affects the number of repetitions, PSE and total work performed, supporting the importance of the order of exercises as an important variable in training prescription.

Efeito da massagem clássica na percepção subjetiva de dor, edema, amplitude articular e força máxima após dor muscular tardia induzida pelo exercício / Effect of classical massage on subjective perceived soreness, edema, range of motion and maximum strength after delayed onset muscle soreness induced by exercise

O treino de força com cargas elevadas tem induzido indivíduos a apresentarem sintomas de dano muscular que incluem a dor muscular tardia. Na tentativa de diminuir sintomas e desconforto da DOMS, estratégias têm sido utilizadas, entre elas, a massagem. O objetivo do presente estudo foi verificar os efeitos da massagem clássica na percepção subjetiva de dor (DOMS), circunferência do braço (CIR), amplitude de movimento (ADM) e força máxima (1RM) após protocolo para indução de DOMS. Para isso, 18 adultos jovens saudáveis do gênero masculino foram divididos em três grupos (G1 = massagem; G2 = protocolo; G3 = protocolo + massagem) equalizados pelo teste de uma força máxima de flexão de cotovelo no banco Scott. O protocolo de indução de DOMS consistiu de 30 ações excêntricas musculares supramáximas (seis séries de cinco repetições a 110 por cento de 1RM). A massagem foi realizada no grupo G3 imediatamente após o protocolo durante seis minutos. As variáveis dependentes (DOMS, CIR, ADM) foram avaliadas 24, 48, 72 e 96 horas após o protocolo, enquanto a força máxima, apenas após 48 e 96 horas. Os resultados indicaram aumento na DOMS e diminuição na ADM e 1RM, similar aos de outros estudos que utilizaram protocolos semelhantes. No entanto, não houve diferenças entre os grupos G2 e G3 em nenhuma das variáveis analisadas. Pode-se concluir que com esse design experimental o protocolo utilizado foi eficaz para provocar as alterações nas variáveis analisadas e a massagem não causou nenhum benefício na recuperação das funções musculares nem na percepção subjetiva de dor.

Heavy resistance training induces to symptoms of muscle damage which include delayed onset muscle soreness (DOMS). Some strategies (i.e. massage) have been used to attenuate these symptoms and to reduce discomfort associated with DOMS. This study aimed to investigate the effects of classical massage on DOMS perception, limb girth (CIR), range of motion (ADM) and maximum strength performance (1-RM) after a muscle damage protocol. Eighteen males were divided into three groups (G1= massage-only, G2= protocol-only, G3= protocol + massage) according to their 1-RM values. DOMS-inducing protocol consisted of 30 supramaximal eccentric contractions (6 sets of 5 repetitions at 110 percent 1RM). Immediately after the protocol, classical massage was performed in G3 for 6 minutes. DOMS, CIR, ADM were assessed 24, 48, 72 and 96 hours after the muscle damage protocol, and maximum strength was evaluated only after 48 and 96 hours. Results showed increase in DOMS and reduction in ADM and 1-RM values, in agreement with other studies using similar procedures. However, there was no difference between G2 and G3 in any of the assessed variables. It can be concluded that the muscle damage protocol used in this study was effective in causing alteration in the dependent variables observed. However, classical massage was not effective to minimize the symptoms associated to exercise induced muscle damage.

Adaptações neurais e morfológicas ao treinamento de força com ações excêntricas / Neural and morphological adaptations to resistance training with eccentric actions

A ação excêntrica tem sido estudada devido a possibilidade de otimizar as respostas adaptativas dos músculos aos estímulos do treinamento de força. Essas respostas incluem maiores ganhos de força e hipertrofia decorrentes de um treinamento com apenas ações excêntricas. É provável que essas adaptações sejam conseqüência dos eventos que ocorrem na estrutura neuromuscular em função das diferentes características neurais e mecânicas associadas a este tipo de ação. A maior ocorrência de lesão, o maior grau de tensão sobre as fibras musculares ativas e o alongamento a que estas são submetidas aparentam maximizar as respostas ao treinamento de força.

Eccentric action has been studied because it optimizes muscle adaptive responses to resistance training. These responses encompass higher strength gains and hypertrophy. These adaptations seem to result from events occurring in the neuromuscular structure because of different neural and mechanical characteristics associated with this type of muscle action. Muscle damage, higher tension and stretching on active fibers appear to maximize muscle responses to resistance training with eccentric actions.

Potencialização: a influência da contração muscular prévia no desempenho da força rápida / Potentiation: the influence of previous muscle contraction on speed-strength performance

A ampliação da força decorrente de uma atividade prévia é conhecida como potencialização. Neste estudo investigouse a potencialização da força rápida, avaliada por meio dosalto vertical (SV), causada por atividades do ciclo alongamento-encurtamento e ações isométricas máximas. Dezoito jovens do sexo masculino foram divididos em trêsgrupos: Salto em Profundidade (SP,n=6), Isometria Máxima(IM,n=6) e Controle (CON,n=6). O grupo SP foi submetido a 4 x 5 saltos (40 cm). O grupo IM realizou 3 contrações isométricas máximas de 5 segundos de duração. O desempenho no SV foi avaliado no aparelho Ergojump, pré e nos intervalos de 5, 10 e 15 minutos pós-tratamento. ANOVA demonstrou não haver diferenças significantes no SV entre os grupos e intervalos de tempo. O grupo SP sofreuuma queda média no desempenho de 1,6 cm (41,2 ± 2,6 cm pré para 39,6 ± 2,6 cm pós). O grupo IM também teve queda de 1,4cm (41,6 ± 4,6 cm pré para 40,2 ± 4,5 cm pós) e o grupoCON diminui 1,0 cm (40,8 ± 4,6 cm pré para 39,8 ± 4,6 cmpós). Assim, não foi possível esclarecer qual tipo de ação muscular é mais eficiente em desencadear a potencialização. O nível de experiência dos sujeitos em treinamento de forçapode ter sido um importante fator na ausência da potencialização.

Intensification of strength due to a previous activity is known as potentiation. In this study we investigated quick strength potentiation, evaluated through vertical jump (VJ) performance, caused by activities of the stretch-shortening cycle and maximum isometric contractions...

Fístula vesicovaginal extensa, com destruição completa da uretra, produzida por míise, em paciente com prolapso genital total / Extensive vesicovaginal fístula, with total destruction of urethra, produced for myiasis, in a patient with total genital prolapsus

Apresenta-se caso raríssimo, único, talvez de fístula vesicovaginal extensa, produzida por miíase, com destruição total da uretra, em paciente de 83 anos, portadora de prolapso gential total. O tratamento, cumprido em tempo único, constou de fechamento da criação de "neoretra" com mecanismo de contenção miccional e histerocolpectomia total. São feitos comentários acerca das miíases em geral, da genital em particular e inclusive, princípios de profilaxia. discutem-se também, alguns passos da técnica cirúrgica empregada, máxime no que atina à contenção urinária