Biblioteca Digital

Aim: Strength and endurance training are two common forms of motor training which induce distinct adaptive neuromuscular responses. There is a considerable debate on the neural adaptations which accompany strength training and little is known about the effects of endurance training. This study investigated changes in motor output and motor unit behavior following 6 weeks of either strength or endurance training. Methods: Twenty-eight sedentary healthy men (age, mean ± SD, 26.1 ± 3.9 yr) were randomly assigned to one of 3 groups: strength training (ST); endurance training (ET) and; control (C; no exercise intervention). The training was performed three days per week, over a period of 6 weeks. Maximum voluntary force (MVC), time-to-task failure at 30% MVC, and rate of force development (RDF) of the knee extensors were measured before and post training (week 7). Additionally, motor unit behavior and muscle activity were studied with intramuscular and surface EMG recordings from the vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles during sustained isometric knee extensions at 10% and 30% MVC. The surface EMG was recorded also during MVC and explosive isometric contractions. Results: In the ST group, the percent change post-training in MVC and RFD was significantly greater (13.8 ± 3.6% and 19.8 ± 5.9%...

AIM: The aim of this study was to investigate the effect of strength and endurance training on the conduction velocity of vastus medialis obliquus and lateralis single motor units during voluntary sustained knee extensions. METHODS: Seventeen sedentary healthy men (age, mean ± SD, 26.3 ± 3.9 yr) were randomly assigned to one of 2 groups: strength training (ST, n= 8) or endurance training (ET, n= 9). Conventional endurance and strength training was performed three days per week, over a period of 6 weeks. Motor unit conduction velocity (MUCV), maximum voluntary force (MVC) and time-to-task failure at 30% MVC of the knee extensors were measured before and immediately following training. To assess MUCV, multi-channel surface and intramuscular EMG signals were concurrently recorded from the vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles during 60-s isometric knee extensions at 10% and 30% of MVC. RESULTS: After 6 weeks of training, MVC increased in the ST group (16.7 ± 7.4 %; P < 0.05) whereas time to task failure was prolonged in the ET group (33.3 ± 14.2 %; P < 0.05). Both training programs induced an increase in motor unit conduction velocity at both 10% and 30% MVC (P < 0.01). Furthermore after both training programs...

Objective. - The aim of this study was to identify the effects of strength training on plasma parameters, body composition and the liver of ovariectomized rats. Methods. - Wistar sedentary (SHAM), ovariectomized (OVX), and ovariectomized trained rats (strength training [OVX-EXE]) of 85% of one maximal repetition (1 RM), three times per week, for 10 weeks, were used on this study. We monitored the body weight and visceral (uterine, mesenteric and retroperitoneal) and subcutaneous adiposity, total cholesterol, triglycerides, HDL, blood glucose and liver morphology to identify the presence of macrovesicular steotosis (haematoxylin and eosin staining). Results. - We observed that strength training changed body weight (SHAM 293.0 +/- 14.5 g; OVX 342.6 +/- 10.8 g; OVX-EXE 317.7 +/- 11.9 g, P < 0.05), visceral and subcutaneous adiposity, glucose (SHAM 111.2 +/- 10.0 mg/dL; OVX 147.4 +/- 18.8 mg/dL; OVX-EXE 118.5 +/- 2.2 mg/dL, P < 0.05), increased HDL (SHAM 82.7 +/- 1.4 mg/dL; OVX 64.6 +/- 2.8 mg/dL; OVX-EXE 91.4 +/- 2.6 mg/dL, P < 0.05) and reduced macrovesicular steatosis in liver tissue. Conclusions. - Considering the data obtained in this research, we emphasise the use of strength exercise training as a therapeutic means to combat or control the metabolic disturbances associated with menopause...

O uso de equipamentos para trabalho de força tem sofrido grande aumento com a popularização das academias de ginástica e a prática de musculação. Os primeiros equipamentos surgiram para o uso em treinamentos esportivos de atletas, mas com os avanços nos estudos da medicina e o aumento do sedentarismo da população em geral, passaram a ser utilizados por público diversificado, para manutenção e reabilitação da saúde. Existem vários tipos de equipamentos de força. Há tanto estações para a realização de exercícios variados, bem como aparelhos especiais para determinados exercícios. Os equipamentos diferenciam-se entre si pelo uso de diversos recursos mecânicos, para realização de trabalho resistido (pesos com cabos e roldanas, motores elétricos, pistões hidráulicos e outros), bem como por suas distintas possibilidades de ajustes (antropométricos, posturais e de carga), para a realização de exercícios. Este estudo visa analisar a usabilidade dos sistemas de ajuste de alguns equipamentos para musculação, existentes no mercado brasileiro, do ponto de vista da ergonomia, para verificar sua praticidade e eficácia.; The use of equipment for strength training has greatly increased with the popularization of gymnastic academies and strength training practice. Such equipments were originally used for athletic training...

O inexorável declínio das capacidades motoras ao longo do envelhecimento propicia uma população idosa com diversas limitações funcionais. Dentre estas, a capacidade de locomoção, por estar associada ao risco de queda, tem sido objeto de estudo de diversos trabalhos. A adoção do treinamento de força e de potência como estratégia de intervenção para atenuar os efeitos negativos do processo fisiológico ou patológico do envelhecimento têm sido bastante discutidas. Contudo, os efeitos dessas intervenções em indicadores biomecânicos da marcha não foram ainda plenamente debatidos. Desta forma, o presente trabalho teve como objetivo comparar os efeitos desses dois protocolos de treinamento nas capacidades funcionais e em parâmetros biomecânicos da marcha de idosas. Foram formados três grupos de estudo do sexo feminino, homogeneizados pela idade, índice de massa corporal e nível de atividade física: o grupo controle (GC: n=8, 69±4 anos de idade), o grupo força (GF: n=6, 67±4 anos de idade) e o grupo potência (GP: n=7, 68±4 anos de idade). Ao GC não foi induzida qualquer atividade extra à sua rotina. Já o GF e o GP foram submetidos a 12 semanas de treinamento de força e de potência, respectivamente, com periodicidade semanal de três sessões. Enquanto que o GF executou os exercícios propostos com velocidade moderada (70-90% de 1RM)...

O objetivo geral deste estudo foi avaliar e comparar os efeitos de dois modelos de periodização de treinamento de força na densidade mineral óssea (DMO), na força muscular dinâmica máxima (1-RM) e submáxima (20-RM), parâmetros de lesão muscular e parâmetros antropométricos de mulheres na prémenopausa. Vinte e sete mulheres, sem osteopenia ou osteoporose, foram divididas aleatoriamente em dois grupos experimentais: (1) treinamento de força com periodização linear (GPL – n=14), com intensidades de 18 – 8 repetições máximas (RM); e (2) treinamento de força com periodização ondulada (GPO – n=13), com intensidades de 12 – 8-RM. Ambos os grupos treinaram 3 vezes por semana, durante 28 semanas. O treinamento foi dividido em 4 mesociclos: no 1° mesociclo (primeiras 4 semanas), ambos os grupos executaram 3 séries de 20-RM, em todos os 8 exercícios selecionados, para adaptação. Os parâmetros de lesão muscular, avaliados em vários momentos do treinamento, foram as concentrações sangüíneas de creatina quinase (CK) e a dor muscular tardia (DMT). Os parâmetros antropométricos mensurados foram o somatório de 3 dobras cutâneas (ΣDC) e a perimetria (PE). A análise dos dados, no decorrer do tempo, foi feita...

The purpose of this study was to investigate if chronic eccentric strength training (ST) affects heart rate (HR) and heart rate variability (HRV) during sub-maximal isometric voluntary contractions (SIVC). The training group (TG) (9 men, 62 ± 2) was submitted to ST (12 weeks, 2 days/week, 2 - 4 sets of 8-12 repetitions at 75-80% peak torque (PT). The control group (CG) (8 men, 64 ± 4) did not perform ST. The HR and the HRV (RMSSD index) were evaluated during SIVC of the knee extension (15, 30 and 40% of PT). ST increased the eccentric torque only in TG, but did not change the isometric PT and the duration of SIVC. During SIVC, the HR response pattern and the RMSSD index were similar for both groups in pre- and post-training evaluations. Although ST increased the eccentric torque in the TG, it did not generate changes in HR or HRV. © Springer-Verlag 2008.

O objetivo do presente estudo foi analisar as adaptações ao treinamento com ênfase nas ações musculares excêntricas (EXC). Os dados foram coletados durante uma disciplina eletiva oferecida aos alunos do curso de Educação Física da UNICAMP. Ao longo do semestre, além dos treinamentos, ministramos aulas expositivas, discussões em grupo sobre a forma de tratamentos dos dados para a pesquisa, e também fundamentações acerca da metodologia do treinamento de força. Realizamos também uma revisão sobre as adaptações musculares ao treinamento de força com ênfase nas ações excêntricas, contida na Introdução do trabalho, e que foi utilizada como material didático na disciplina. No primeiro experimento observamos as adaptações promovidas por 13 sessões de treino na magnitude de lesão à célula, respostas inflamatórias, composição corporal, força muscular (FM), resistência de força (RF), consumo máximo de oxigênio (VO2max), limiar ventilatório, e ponto de compensação respiratório. No segundo experimento verificamos se protocolos com ações musculares concêntricas (ACON), concêntricas e excêntricas (ACON/EXC) e somente excêntricas (AEXC) durante o exercício prévio, geraria respostas distintas no tocante a ocorrência da potencialização pós-ativação (PPA). No primeiro estudo testes de FM...

Introduction The purpose of this study was to evaluate de effects of 16 week compensatory strength training program in shoulder rotators balance and muscular fatigue in young swimmers. Methods A total of 40 male swimmers were assessed and randomly divided in two groups: experimental group (n=20; age: 14.65±0.67 years old, height: 173.48±6.87 cm, body mass: 63.15±5.68 kg) and control group (n=20; age: 14.60±0.60 years old, height: 170.79±6.48 cm, body mass: 61.73±4.68 kg). Experimental subjects participated in a 16 week shoulder strength program with Thera-Band® elastic bands (3 times a week). The external rotator (ER)/internal rotators (IR) ratio and fatigue ratio were measured in both groups at baseline and after 16 weeks. Concentric action at 60º/s (3 reps) and 180º/s (20 reps) were measured, in a seated position, with the shoulder at 90º of abduction and elbow flexion, using an isokinetic dynamometer (Biodex System 3). The muscular fatigue protocol consisted in 20 maximal-effort repetitions of ER and IR at 180º/s. Anova with repeated measures was used to determine significant main effects in unilateral ER/IR ratios and fatigue ratios. The level of significance was set at 0.05. Results Considering ER/IR ratio, a compensatory strength training programme induces significant differences in both shoulders at 60º/s (Dominant: P=0.001; Non dominant: P=0.001). At 180º/s we just found significant effects on the Dominant shoulder ER/IR ratio (P=0.002). With respect to fatigue ratios...

EFFECTS OF COMPENSATORY STRENGTH TRAINING PROGRAM ON SHOULDER ROTATOR CUFF BALANCE AND MUSCULAR FATIGUE IN YOUNG SWIMMERS Batalha, N.,1 Raimundo, A.1,2, Tomas-Carus,P.1,2, Pereira, C.1 Silva, A.J.3,4 1:University of Évora, Portugal, 2:Health Science and Technology Research Centre, 3:University of Trás-os-Montes and Alto Douro, Portugal, 4:Research Centre of Sports, Health and Human Development. Introduction The purpose of this study was to evaluate de effects of 16 week compensatory strength training program in shoulder rotators balance and muscular fatigue in young swimmers. Methods A total of 40 male swimmers were assessed and randomly divided in two groups: experimental group (n=20; age: 14.65±0.67 years old, height: 173.48±6.87 cm, body mass: 63.15±5.68 kg) and control group (n=20; age: 14.60±0.60 years old, height: 170.79±6.48 cm, body mass: 61.73±4.68 kg). Experimental subjects participated in a 16 week shoulder strength program with Thera-Band® elastic bands (3 times a week). The external rotator (ER)/internal rotators (IR) ratio and fatigue ratio were measured in both groups at baseline and after 16 weeks. Concentric action at 60º/s (3 reps) and 180º/s (20 reps) were measured, in a seated position, with the shoulder at 90º of abduction and elbow flexion...

INTRODUCTION The purpose of this study was to evaluate de effects of 16 week compensatory strength training program in shoulder strength and respective conventional ratios (concentric ER/IR). METHODS A total of 40 national level male swimmers were assessed and randomly divided in two groups – experimental group (N=20)-(age:14.65±0.67 years old, height:173.48±6.87 cm, body mass:63.15±5.68 kg) and control group (N=20)-(age:14.60±0.60 years old, height: 170.79±6.48 cm, body mass:61.73±4.68 kg). Experimental subjects participated in a 16 week shoulder strength program with Thera-Band® elastic bands (3 times a week). The peak-torque of shoulder internal (IR) and external rotators (ER) was measured in both groups at baseline and after 16 weeks. Concentric action at 60º/s (3 rep) and 180º/s (20 rep) were measured, in a seated position, with the shoulder at 90º of abduction and the elbow flexed to 90º, using an isokinetic dynamometer (Biodex System 3 – Biodex Corp., Shirley, USA). Anova with repeated measures was used to determine significant main effects in shoulder rotators strength and unilateral ER/IR ratios. The level of significance was set at 0.05. RESULTS Significant differences were found in all variables that measure the ER shoulder strength at 60º/s in dominant(DT) (P=0.031) and non-dominant(NDT) shoulder (P=0.001). Meanwhile concentric action at 180º/s...

INTRODUCTION The purpose of this study was to evaluate de effects of 16 week compensatory strength training program in shoulder strength and respective conventional ratios (concentric ER/IR). METHODS A total of 40 national level male swimmers were assessed and randomly divided in two groups – experimental group (N=20)-(age:14.65±0.67 years old, height:173.48±6.87 cm, body mass:63.15±5.68 kg) and control group (N=20)-(age:14.60±0.60 years old, height: 170.79±6.48 cm, body mass:61.73±4.68 kg). Experimental subjects participated in a 16 week shoulder strength program with Thera-Band® elastic bands (3 times a week). The peak-torque of shoulder internal (IR) and external rotators (ER) was measured in both groups at baseline and after 16 weeks. Concentric action at 60º/s (3 rep) and 180º/s (20 rep) were measured, in a seated position, with the shoulder at 90º of abduction and the elbow flexed to 90º, using an isokinetic dynamometer (Biodex System 3 – Biodex Corp., Shirley, USA). Anova with repeated measures was used to determine significant main effects in shoulder rotators strength and unilateral ER/IR ratios. The level of significance was set at 0.05. RESULTS Significant differences were found in all variables that measure the ER shoulder strength at 60º/s in dominant(DT) (P=0.031) and non-dominant(NDT) shoulder (P=0.001). Meanwhile concentric action at 180º/s...

INTRODUCTION: Wheelchair basketball is a paralympic sport characterized by intermittent high-intensity activities that require explosive strength and speed. OBJECTIVE: To investigate the effect of explosive strength training on speed and agility performance in wheelchair basketball players. METHODS: Ten male wheelchair basketball players (Mage=31±4 yrs) were divided into two groups [i.e. explosive strength training (ES); control (CN)] based on International Wheelchair Basketball Federation (IWBF) classification scores. The ES group underwent 6-weeks of training, twice weekly, at 50% 1RM, 10-12 repetitions and 3-4 sets in addition to routine training. Effects of training were measured by the 20 m sprint test and Illinois agility test. RESULTS: The ES group, showed significantly higher increases in speed and agility performance (p ≤ .05). CONCLUSION: A short-duration (i.e. 6-week) explosive strength training programme in wheelchair basketball athletes results in significant improvements in sprint and agility performance.

The strength training of produces improvements in the skeletal muscle as to the muscular hypertrophy, already the aerobic training produces an increase in him I number and in the size of the mitochondria. The objective was verifying the answers of the aerobic training and of force in the aerobic variables. The study was composed of 3 groups. The Aerobic Group (G1) that performed 6 weeks of training of aerobic, the Strength Group (G2) that did a program of 6 strength training weeks and the Group Control (GC). The evaluations of the study occurred in 2 moments: before of the training and in the week 6. We evaluate the VO2MAX, to mechanical power and the IErg. The G1 presented significant differences in all the variables analyzed, while the G2 presented significant difference in the VO2MÁX The study found an increase more marked in the aerobic instalments as answer of the aerobic training regarding the of force.

peer-reviewed; Introduction Strength training can improve neuromuscular function in athletes (Zatsiorky, 1995). Previous literature has demonstrated that strength training can improve key performance indicators (i.e. economy, velocity at VO2 max, & anaerobic power/capacity) in competitive distance runners (Beattie et al., 2014). However, the practice of strength training in distance runners is still a novel training modality. Traditionally, for unknown reasons, distance runners have been cautious to strength train. One potential reason is that athletes and coaches are unaware of the neural adaptations of strength training (musculotendinous stiffness, motor unit recruitment and synchronisation, rate coding, intra- and inter-muscular coordination, and neural inhibition), and deliberate that strength training results solely in increased muscle mass, negatively effecting relative aerobic power and performance. The purpose of this study was to examine the effect of a 40 week strength intervention on body composition variables (mass, % body fat, overall-lean & leg-lean muscle) in competitive distance runners. Methodology Twenty competitive club-standard distance runners (n = 20; 28.2 ± 8.6 years; 71.6 ± 6.6 kg; 180.1 ± 6.8 cm) participated in the 40 week study. Participants were divided into two groups based on their personal preference. The two groups consisted of a ‘strength’ intervention group (ST; n = 11; 29.5 ± 10.0 years; 72.8 ± 6.6 kg; 182.8 ± 8 cm)...

Neste estudo, avaliamos o efeito da restrição calórica e do treinamento resistido na massa corporal e na sensibilidade à insulina de ratas ovariectomizadas. 80 ratas fêmeas da linhagem Holtzman foram distribuídas em 8 grupos (n=10 cada): ovariectomizado (OVX), ovariectomizado com restrição calórica (OVX RC), ovariectomizado com treinamento resistido (OVX TR), ovariectomizado com restrição calórica e treinamento resistido (OVX TR+RC), Sham operado (SHAM), Sham com restrição calórica (SHAM RC), sham com treinamento resistido (SHAM TR), sham com restrição calórica e treinamento resistido (SHAM TR+RC). Após 13 semanas de intervenção, foram analisados: massa corporal, gordura corporal; concentrações sanguíneas de glicose, insulina e adiponectina; conteúdo de AKT total e fosforilada, pi3k e Glut 4 (nos tecidos adiposos subcutâneo e retroperitoneal). As ratas ovariectomizadas (OVX, OVX RC, OVX TR e OVX TR+RC) apresentaram maior massa corporal e gordura corporal quando comparadas ao grupo SHAM. As concentrações de glicose e insulina foram semelhantes em todos os grupos experimentais, porém a concentração de adiponectina foi menor nos grupos ovariectomizados (OVX, OVX RC, OVX TR e OVX TR+RC), quando comparados ao grupo SHAM. A RC e o TR aumentaram a concentração de adiponectina quando comparado ao grupo OVX. Não houve diferença entre os grupos em relação à via de sinalização da insulina nos tecidos adiposos subcutâneo e retroperitoneal. Concluímos que a ovariectomia causa aumento de massa e gordura corporal...

The aim of this study was to verify the effects of strength training on the muscular strength-aerobic erformance relationship. Sixteen swimmers were assigned to control (CG) or experimental (EG) groups and underwent seventeen weeks of swimming training. Swimmers in the EG also performed dry land strength training (DLST), lasting twelve weeks, and aiming to develop power. A 10 minutes test (T10) was taken before and after the 12 weeks of DLST, in order to evaluate aerobic resistance, one maximum voluntary contraction (1MVC) and maximum repetition in 30s (REM) using 70% of 1MVC, where total weight was calculated. Total weight, T10, and 1MVC were all normalized for body mass. There was no signifi cant correlation between percent changes in T10 and dry land muscle strength, despite signifi cant increases being detected in dry land muscle strength. It can be concluded that nonspecifi c training does not improve aerobic performance in swimming.; O objetivo deste estudo foi verificar os efeitos do treinamento de força na relação força muscular fora da águadesempenho aeróbio dentro da água. Dezesseis nadadores foram divididos em grupos controle (GC) e experimental (GE), e submetidos a dezessete semanas de treinamento dentro da água. O GE também realizou um treinamento de força fora da água (TFFA)...

The present study reviews the results reported in the literature regarding energy expenditure in strength training (ST). For this purpose, a search was conducted in the Medline and Sport Discus databases using the following key words: strength training, energy expenditure, and excess post-exercise oxygen consumption (EPOC). The studies analyzed report that ST protocols involving exercises for the major muscle groups characterized by high-intensity and high-volume training and low resting intervals between sets and exercises have a greater metabolic impact on ST. These variables also interfere with the magnitude and duration of EPOC; O presente estudo revisa os resultados encontrados, até então, na literatura, relativos ao dispêndio energético (DE) no treino de força (TF). Para tanto, foi realizado um levantamento bibliográfico nas bases de dados Medline e Sport Discus, utilizando as palavras-chave: strength training, energy expenditure e excess post-exercise oxygen consumption (EPOC). Os estudos analisados referem que protocolos de TF que envolvam exercícios para grandes grupos musculares, com grandes intensidades e volumes de treinamento, e menores intervalos de recuperação entre séries e exercícios são os que apresentam maior impacto metabólico na sessão de treino. Essas mesmas variáveis também demonstram interferir na magnitude e na duração do EPOC.

http://dx.doi.org/10.5007/1980-0037.2012v14n6p749Vários estudos têm demonstrado uma menor capacidade de gerar força quando os exercícios de um programa de treinamento são executados bilateralmente em relação à soma da força executada pelos membros separadamente. Esse fenômeno, que tem sido bem descrito na literatura científica, é chamado de déficit bilateral. Os mecanismos causadores do déficit não são totalmente claros, mas parecem estar relacionados a mecanismos neu­rais, como um bloqueio dos hemisférios cerebrais ocorrido durante a contração bilateral que reduz a ativação de unidades motoras e a força produzida. Em relação a cada forma de execução (unilateral e bilateral) a longo prazo, as adaptações parecem ser específicas ao tipo de contração utilizada durante o treinamento. Portanto, em consideração à rele­vância da realização de exercícios executados unilateralmente e bilateralmente dentro de um programa de treino de força, assim como o efeito de cada forma de execução a longo prazo nas adaptações morfológicas e neurológicas do treinamento, esse artigo teve como objetivos caracterizar o fenômeno déficit bilateral, explorar seus principais mecanismos causadores, bem como discutir a influência de cada tipo de treinamento (unilateral e bilateral) nas adaptações do treinamento de força.; http://dx.doi.org/10.5007/1980-0037.2012v14n6p749Several studies have demonstrated a lower capacity to generate force when the exercises of the training program are performed bilaterally than when compared to the sum of the strength produced by each limb separately. This phenomenon...

Objectives: To investigate and compare the effects of strength training (Shoulder girdle and respiratory muscles) and drug (Jatamansi) on reducing hand tremor in archers. Design: Randomized experimental, different subject design. Setting: Institutional study done at Manipur Archery Association. Interventions: Thera-band (Hygienic Corporation) and Nardostachys jatamansi (GMP Certified) were used as interventions. Pre & Post Hand Steadiness Score (Arm-Hand-Steadiness Tester on 4 mm hole) and Performance Test Scores (AAPHER Archery Test) was evaluated. 45 National Level Archers within age 16-28yrs were assigned into three groups: Group I (Medicine), Group II (Strength Training) and Group III (Control). Medicine was consumed for 4 weeks continuously 3 gm TDS and Thera-band strength training was given for 3 times weekly for 4 weeks. Main Outcome Measures: It was hypothesized that strength training is more effective in reducing hand tremors than medicinal or control groups. Results: Arm-Hand-Steadiness: Numbers of Contact (NOC): On inter Group Comparison of the three Groups using One Way ANOVA, left and right arm showed significant differences (F = 5.64, p<0.05; F = 8.97, p<0.001) respectively and on Post Hoc Scheffe’s analysis, Group II showed maximum improvement. Total Contact Time (TCT): On inter Group comparison of the three Groups using One Way ANOVA...