No abstract

Mechanical stimuli have often been suggested to be the major determinant of resistance training adaptations; however, some studies suggested that metabolic changes also play an important role in the gains of muscle size and strength. Several resistance training methods (RTM) have been employed with the purpose of manipulating mechanical and metabolic stimuli; however, information about their physiological effects are scarce. The objective of this study was to compare the time under tension (TUT) and blood lactate responses among four different RTM reported in the literature. The four RTM were performed in a knee extension machine at 10 repetition maximum (RM) load by 12 recreationally trained young men. The RTM tested were: 10RM, super-slow (SL-subjects performed one 60-second repetition with 30 seconds for eccentric and 30 seconds for concentric phase), functional isometrics (FI-in each repetition, a five-second maximal isometric contraction was executed with the knees fully extended) and adapted vascular occlusion (VO-subjects performed a 20-second maximal isometric contraction with the knees fully extended and immediately proceeded to normal isoinertial lifts). According to the results, all RTM produced significant increases in blood lactate levels. However, blood lactate responses during FI (4.48Ϯ1.57 mM) and VO (4.23Ϯ1.66 mM) methods were higher than the SL method (3.41Ϯ1.14 mM). The TUT for SL (60 s), FI (56.33Ϯ6.46 s), and VO (53.08Ϯ4.76 s) methods were higher than TUT for 10RM (42.08Ϯ3.18 s). Additionally, TUT for the SL method was higher than TUT during the VO method. Therefore, the SL method may not be recommended if one wants to provide a high metabolic stimulus. The FI method appeared to be especially effective in promoting both type of stimuli.

With the purpose of manipulating training stimuli, several techniques have been employed to resistance training. Two of the most popular techniques are the pre-exhaustion (PRE) and priority system (PS). PRE involves exercising the same muscle or muscle group to the point of muscular failure using a single-joint exercise immediately before a multi-joint exercise (e.g., peck-deck followed by chest press). On the other hand, it is often recommended that the complex exercises should be performed first in a training session (i.e., chest press before peck-deck), a technique known as PS. The purpose of the present study was to compare upper-body muscle activation, total repetitions (TR), and total work (TW) during PRE and PS. Thirteen men (age 25.08 +/- 2.58 years) with recreational weight-training experience performed 1 set of PRE and 1 set of PS in a balanced crossover design. The exercises were performed at the load obtained in a 10 repetition maximum (10RM) test. Therefore, chest press and peck-deck were performed with the same load during PRE and PS. Electromyography (EMG) was recorded from the triceps brachii (TB), anterior deltoids, and pectoralis major during both exercises. According to the results, TW and TR were not significantly different (p > 0.05) between PRE and PS. Likewise, during the peck-deck exercise, no significant (p > 0.05) EMG change was observed between PRE and PS order. However, TB activity was significantly (p < 0.05) higher when chest press was performed after the peck-deck exercise (PRE). Our findings suggest that performing pre-exhaustion exercise is no more effective in increasing the activation of the prefatigued muscles during the multi-joint exercise. Also, independent of the exercise order (PRE vs. PS), TW is similar when performing exercises for the same muscle group. In summary, if the coach wants to maximize the athlete performance in 1 specific resistance exercise, this exercise should be placed at the beginning of the training session.

Several resistance training methods (RTM) have been developed in order to manipulate physiological stimuli and obtain better results with training. The purpose of this study is to compare the metabolic and mechanical responses among seven different RTM reported in the literature. The RTM were compared with regard to blood lactate, time under tension (TUT) and total loading (TUT x load) in recreationally trained young men. The RTM tested were 10RM (TEN), super-slow (SL), functional isometrics (FI), adapted vascular occlusion (VO), 6RM (SIX), forced repetitions (FR) and breakdowns (BD). All RTM produced significant increases in blood lactate, with no difference among them. The BD method elicited higher TUT and total loading compared to the other RTM tested.

The purpose of the study was to investigate the effects of different between-set rest interval durations on muscle strength after 12 weeks of resistance training. After baseline tests, 34 nonresistance trained college-aged men were matched and randomly assigned to 2 groups. Both groups trained twice a week and performed the same exercises and the same work output with 2 sets of 8 to 12 repetitions until volitional fatigue. One group (n = 18, 21.4 +/- 3.2 yr; 73.8 +/- 14.0 kg; 175.9 +/- 7.8 cm) used short-rest intervals (SR) with a work rest ratio of approximately 1:3; the other (n = 16, 22.4 +/- 2.6 yr; 73.1 +/- 13.6 kg; 171.9 +/- 8.2 cm) used long-rest intervals (LR) with a work rest ratio of approximately 1:6. Leg press and bench press 1 repetition maximum (1RM) were measured at baseline and after the end of the training period. The increases in 1RM for bench press were 14.4 +/- 8.1% for the SR group and 10.5 +/- 6.4% for the LR group (p < 0.05). For the leg press, the increases were 17.5 +/- 9.2% with SR training and 17.8 +/- 12.3% for the LR group (p < 0.05). The results did not reveal significant differences between SR and LR for the bench press or leg press 1RM (p > 0.05). Our data suggest that gains in maximum strength in nontrained men are not dependent on the length of the rest interval between sets. Therefore, personal trainers and strength coaches can advise beginning lifters to use short rest intervals to make best use of their time in the weight room.

The identification of the characteristics of each movement and its adjustment to the training goals are tasks that demand the interaction of many knowledge areas. These tasks are essential to the success in sports activities and training programs designed with athletic, aesthetic or healthy purposes. The objective of the present study was to compare the electromyographic (EMG) activity of the pectoralis major (PM), anterior deltoids (DA) and triceps brachii (TB) muscles during the barbell bench press (SP) and the peck deck (PD) exercises. EMG activity of TB, PM and DA were assessed during 10 maximum repetitions performed in SP and PD in 13 trained men. The results did not show any differences between exercises for PM and DA activity; however, TB activity was higher for SP than PD exercise. During SP, the PM muscle activity was higher than TB. There were no differences between PM and DA, or between DA and TB. During the PD exercise, the PM and DA muscle activities were higher than TB. There were no differences between PM and DA. It was concluded that the prime movers of both exercise are DA and PM, and there are no differences between them. Therefore, both PD and SP could be performed with the purpose to stimulate DA and PM muscles, depending on the availability of the equipments and/or the specificity of the motor tasks.