RESUMO

This study investigated the effects of a 10-week resistance training to failure on neuromuscular adaptations in young women. Eighty-nine active young women were randomly assigned to one of three groups: 1) repetitions to failure (RF; three sets of repetitions to failure); 2) repetitions not to failure with equalized volume (RNFV; four sets of 7 repetitions); and 3) repetitions not to failure (RNF; three sets of 7 repetitions). All groups performed the elbow flexor exercise (bilateral biceps curl) and trained 2 days per week using 70% of 1RM. There were significant increases (p<0.05) in muscle strength after 5 (15.9% for RF, 18.4% for RNF, and 19.9% for RNFV) and 10 (28.3% for RF, 26.8% for RNF, and 28.3% for RNFV) weeks of training, with no significant differences between groups. Additionally, muscular endurance increased after 5 and 10 weeks, with no differences between groups. However, peak torque (PT) increased significantly at 180°.s-1 in the RNFV (13.7%) and RNF (4.1%) groups (p<0.05), whereas no changes were observed in the RF group (-0.5%). Muscle thickness increased significantly (p<0.05) in the RF and RNFV groups after 5 (RF: 8.4% and RNFV: 2.3%) and 10 weeks of training (RF: 17.5%, and RNFV: 8.5%), whereas no significant changes were observed in the RNF group (3.9 and 2.1% after 5 and 10 weeks, respectively). These data suggest that short-term training of repetitions to failure do not yield additional overall neuromuscular improvements in young women.

RESUMO

Studies investigating the effect of rest interval length (RI) between sets on neuromuscular performance and metabolic response during power training are scarce. Therefore, the purpose of this study was to compare maximal power output, muscular activity and blood lactate concentration following 1, 2 or 3 minutes RI between sets during a squat power training protocol. Twelve resistance-trained men (22.7 ± 3.2 years; 1.79 ± 0.08 cm; 81.8 ± 11.3 kg) performed 6 sets of 6 repetitions of squat exercise at 60% of their 1 repetition maximum. Peak and average power were obtained for each repetition and set using a linear position transducer. Muscular activity and blood lactate were measured pre and post-exercise session. There was no significant difference between RI on peak power and average power. However, peak power decreased 5.6%, 1.9%, and 5.9% after 6 sets using 1, 2 and 3 minutes of RI, respectively. Average power also decreased 10.5% (1 min), 2.6% (2 min), and 4.3% (3 min) after 6 sets. Blood lactate increased similarly during the three training sessions (1-min: 5.5 mMol, 2-min: 4.3 mMol, and 3-min: 4.0 mMol) and no significant changes were observed in the muscle activity after multiple sets, independent of RI length (pooled ES for 1-min: 0.47, 2-min: 0.65, and 3-min: 1.39). From a practical point of view, the results suggest that 1 to 2 minute of RI between sets during squat exercise may be sufficient to recover power output in a designed power training protocol. However, if training duration is malleable, we recommend 2 min of RI for optimal recovery and power output maintenance during the subsequent exercise sets. Key pointsThis study demonstrates that 1 minute of RI between sets is sufficient to maintain maximal power output during multiple sets of a power-based exercise when it is composed of few repetitions and the sets are not performed until failure. Therefore, a short RI should be considered when designing training programs for the development of muscular power.Short RI may be more practical for strength coaches under time constraints (i.e. 1 minute of RI required only 7 minutes to complete an exercise session, while with 2 minutes take 12 minutes, and 17 minutes with 3 minutes of RI).Future research is needed to examine the longitudinal effects of interval rest in training programs designed for the development of muscular power.

RESUMO

The aim of this study was to examine the effect of adding single-joint (SJ) exercises to a multi-joint (MJ) exercise resistance-training program on upper body muscle size and strength. Twenty-nine untrained young men participated in a 10-week training session. They were randomly divided in 2 groups: the MJ group performed only MJ exercises (lat pulldown and bench press); the MJ+SJ group performed the same MJ exercises plus SJ exercises (lat pulldown, bench press, elbow flexion, and elbow extension). Before and after the training period, the muscle thickness (MT) of the elbow flexors was measured with ultrasound, and peak torque (PT) was measured with an isokinetic dynamometer. There was a significant (p < 0.05) increase in MT (6.5% for MJ and 7.04% for MJ+SJ) and PT (10.40% for MJ and 12.85% for MJ+SJ) in both groups, but there were no between-group differences. Therefore, this study showed that the inclusion of SJ exercises in a MJ exercise training program resulted in no additional benefits in terms of muscle size or strength gains in untrained young men.

Assuntos

Força Muscular , Músculo Esquelético , Exercício Físico , Humanos , Hipertrofia , Treinamento Resistido

RESUMO

The purpose of this study was to compare the effect of different rest intervals and contraction velocities on muscle recovery following resistance exercise. 18 children (11.1 ± 0.52 yrs) and 19 adolescents (15.8 ± 0.49 yrs) performed three sets of 10 isokinetic repetitions at 60°/s and 180°/s. The work-to-rest ratio (W/R) was 1:2 and 1:4 for 60°/s, and 1:6 and 1:12 for 180°/s. ANOVA revealed that children demonstrated no significant decline in PT from the first to third set with any rest interval, but there was a significant (p < .05) decline for adolescents when a W/R of 1:2, 1:4 and 1:6 were used. Adolescents demonstrated significantly greater blood lactate (BLa) concentrations than children after three sets of resistance exercise. The present study indicates that adolescents may require longer rest intervals to recover full PT when compared with children.

Assuntos

Articulação do Joelho/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/metabolismo , Treinamento Resistido/métodos , Descanso/fisiologia , Adaptação Fisiológica/fisiologia , Adolescente , Fatores Etários , Análise de Variância , Criança , Humanos , Ácido Láctico/sangue , Masculino , Contração Muscular/fisiologia , Dinamômetro de Força Muscular , Músculo Esquelético/fisiologia , Fatores de Tempo , Torque

RESUMO

Graduated compression stockings have been used as a mechanical method of deep vein thrombosis prophylaxis for several years. Several studies have demonstrated an increase in mean deep venous velocity, reduced venous pooling, improved venous return, and increase blood lactate clearance in subjects who wore graduated compression stockings during exercise. A possible improvement in venous return during and after exercise may facilitate the clearance of metabolites produced during exercise. Also, studies have suggested that compressive clothing can promote tissue regeneration and consequently positively benefit the muscle function following strenuous exercise. However, the results from the previous studies are controversial. Also, the majority of the studies investigated the effects of compression stockings and there is a lack of studies using different compression garments such as compression shorts, shirts and sleeves. Thus, the purpose of this text is to briefly review the possible effects of compression garments on exercise performance and muscle recovery.