Article

A Cross-Sectional Comparison of Different Resistance Training Techniques in the Bench Press

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Abstract

Seven alternative resistance training techniques, performed using a bench press exercise, were compared with heavy weight training (HWT) on a number of variables. These resistance training techniques included isokinetics, eccentrics, functional isometrics, super slow motion, rest pause, breakdowns, and maximal power training. The main results were that eccentrics and isokinetics had significantly (p < 0.05) greater levels of force and integrated electromyography than HWT during the eccentric phase. Likewise, functional isometrics had significantly more force and breakdowns significantly higher triceps brachii electromyography than HWT in the concentric phase. Super slow motion and maximal power training both recorded significantly lower levels of force and integrated electromyography than HWT in each phase. However, super slow motion resulted in significantly greater time under tension (61.70 +/- 2.12 vs. 21.15 +/- 0.92 seconds) than HWT. Maximal power training recorded significantly greater levels of power production than HWT in both the eccentric and concentric phases. Although no alternative resistance training techniques were found to produce significantly greater levels of blood lactate response than HWT, maximal power training and eccentrics produced significantly lower levels. (C) 1999 National Strength and Conditioning Association
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... The Influence of Movement Tempo on Acute Responses to Resistance Training (2020) 00:00 training with different movement tempos. Keogh et al. (58) compared training with VOL, EXP, and SLO movement tempo. Despite significant differences in load and values of TUT in tempos, there were no significant differences in postworkout value of blood lactate between VOL, EXP, and SLO movement tempos. ...
Article
Wilk, M, Tufano, JJ, and Zajac, A. The influence of movement tempo on acute neuromuscular, hormonal, and mechanical responses to resistance exercise—a mini review. J Strength Cond Res XX(X): 000–000, 2020—Resistance training studies mainly analyze variables such as the type and order of exercise, intensity, number of sets, number of repetitions, and duration and frequency of rest periods. However, one variable that is often overlooked in resistance training research, as well as in practice, is premeditated movement tempo, which can influence a myriad of mechanical and physiological factors associated with training and adaptation. Specifically, this article provides an overview of the available scientific literature and describes how slower tempos negatively affect the 1-repetition maximum, the possible load to be used, and the number of repetitions performed with a given load, while also increasing the total time under tension, which can mediate acute cardiovascular and hormonal responses. As a result, coaches should consider testing maximal strength and the maximal number of repetitions that can be performed with each movement tempo that is to be used during training. Otherwise, programming resistance training using various movement tempos is more of a trial-and-error approach, rather than being evidence or practice based. Furthermore, practical applications are provided to show how movement tempo can be adjusted for a variety of case study–type scenarios.
... Considering that most programs include concentric and eccentric muscle actions in a given repetition, there is not much potential for variation in this variable. However, some advanced programs use different forms of isometric training (e.g., functional isometrics (128)), in addition to use of supramaximal eccentric muscle actions in order to maximize gains in strength and hypertrophy (139). These techniques have not been extensively investigated but appear to provide a novel stimulus conducive to increasing muscular strength. ...
Article
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American College of Sports Medicine Position Stand on Progression Models in Resistance Training for Healthy Adults. Med. Sci. Sports Exerc. Vol. 34, No. 2, 2002, pp. 364-380. In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary. The optimal characteristics of strength-specific programs include the use of both concentric and eccentric muscle actions and the performance of both single- and multiple-joint exercises. It is also recommended that the strength program sequence exercises to optimize the quality of the exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher intensity before lower intensity exercises). For initial resistances, it is recommended that loads corresponding to 8-12 repetition maximum (RM) be used in novice training. For intermediate to advanced training, it is recommended that individuals use a wider loading range, from 1-12 RM in a periodized fashion, with eventual emphasis on heavy loading (1-6 RM) using at least 3-min rest periods between sets performed at a moderate contraction velocity (1-2 s concentric. 1-2 s eccentric). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d.wk(-1) for novice and intermediate training and 4-5 d.wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion, with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training, and 2) use of light loads (30-60% of 1 RM) performed at a fast contraction velocity with 2-3 min of rest between sets for multiple sets per exercise. It is also recommended that emphasis be placed on multiple-joint exercises, especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (> 15) using short rest periods (< 90 s). In the interpretation of this position stand, as with prior ones, the recommendations should be viewed in context of the individual's target goals, physical capacity, and training status.
... Bu yüzden maksimal kuvvet gelişim verimi olumsuz etkilenmektedir. [150] Bunun yanında hareket hızının ...
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This study compared the effects of dynamic and static core training programs on speed, agility, related anaerobic power tests, core stability tests and body composition measurements in recreational soccer players. A static (n = 14) and dynamic (n = 13) training group performed three 30 min sessions per week for eight weeks meanwhile attended normal soccer training sessions with a control group (n = 11). Effects of different core training regimes were compared after eight weeks the with repeated measures MANOVA (p<0,05) for field, core stabilization and body composition tests. Sprint (10m-30m), agility (505-Arrowhead), vertical and standing long jump scores did not increased in any groups and no difference found between groups. Neither group demonstrated difference for body composition measurements (weight, body mass index, waist/hip ratio, body fat percentage) for repeated test scores and between groups comparisons. Two experiment groups improved in dynamic and static core stabilization tests except the plank test (for plank test, dynamic and conrtol group has the same score) while control group did not changed. Core stabilization tests showed that the improvements of experiment groups affected by the movement specifity and static training group increased static test scores (plank 23,8% - back isometric 28,9% - leg raise 15,6%) while dynamic training group increased mostly the dynamic test scores (sit-up 21,2%, push up 16,2%). Results indicate that both training types improved movement related measures of core stability but did not transfer into any anaerobic skills and body composition. Core stability training is not generate sufficient stimulus to improve power and strength dependent performance skills like sprint and agility and not required to be the main part of soccer conditioning programs.
... Considering the effect of this relationship on perceived exertion is decisive since set configuration establishes the metabolic (7), hormonal (8), and neuromuscular (16) entailment of the session, with an increased response of these responses in long set configurations in comparison with the short ones (7,8,16). As was previously pointed out, since perceived exertion is able to track these perceptual responses to different loading parameters that are metabolic (29), hormonal (12), or neuromuscular (4) mediated, it seems critical to further explore how set configuration determines the perceptual responses to resistance exercise. ...
Article
Previously, perceived exertion in submaximal resistance exercise protocols was reported to be affected by the intensity of load followed by work-to-rest ratio. Nevertheless, the effect of set configuration, which entails the metabolic, hormonal, and neuromuscular implication of the session is currently unknown, despite that perceived exertion discriminates these differences. We aimed to analyze the effect of three submaximal set configurations on perceived exertion and their relationship with velocity as a mechanical measure of fatigue. Seventeen healthy subjects (23 +/- 2 years) performed with the 10RM load on the leg press (211 +/- 45 kg) a total of 40 repetitions with 720 seconds of rest in three randomized experimental sessions with the same work-to-rest ratio. The sessions consisted of an inter-repetition rest design performing individual repetitions, a cluster design performing groups of four repetitions, and a traditional design performing groups of eight repetitions. At the end of the session, the non-parametric ANOVA-type test revealed differences between protocols (p < 0.001), with lower values of perceived exertion in the inter-repetition rest design in comparison with the cluster design (p = 0.003) and traditional design (p < 0.001). Additionally, Spearman rank correlations (p < 0.001) were observed for the inter-repetition rest design (rho = -0.72) and traditional design (rho = -0.8) between perceived exertion and velocity. Our findings suggest that the submaximal set configuration is a determinant of perceived exertion by itself and that perceived exertion represents similar mechanisms as velocity, such as fatigue and certain characteristics of the session and the individual.
... A total of six selected studies [9][10][11][20][21][22] reported the values of normalized EMG amplitude during BP (Table 2), which can be used to answer our first research question (Which muscles show the greatest activity during the BP?). Two studies [13,15] based their conclusions on normalized EMG but reported the EMG values only in a graphic form; they were included in the review because it was possible to compare them to other studies. ...
Article
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Background The bench press exercise (BP) plays an important role in recreational and professional training, in which muscle activity is an important multifactorial phenomenon. The objective of this paper is to systematically review electromyography (EMG) studies performed on the barbell BP exercise to answer the following research questions: Which muscles show the greatest activity during the flat BP? Which changes in muscle activity are related to specific conditions under which the BP movement is performed? Strategy PubMed, Scopus, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library were searched through June 10, 2016. A combination of the following search terms was used: bench press, chest press, board press, test, measure, assessment, dynamometer, kinematics and biomechanics. Only original, full-text articles were considered. Results The search process resulted in 14 relevant studies that were included in the discussion. The triceps brachii (TB) and pectoralis major (PM) muscles were found to have similar activity during the BP, which was significantly higher than the activity of the anterior deltoid. During the BP movement, muscle activity changes with exercise intensity, velocity of movement, fatigue, mental focus, movement phase and stability conditions, such as bar vibration or unstable surfaces. Under these circumstances, TB is the most common object of activity change. Conclusions PM and TB EMG activity is more dominant and shows greater EMG amplitude than anterior deltoid during the BP. There are six factors that can influence muscle activity during the BP; however, the most important factor is exercise intensity, which interacts with all other factors. The research on muscle activity in the BP has several unresolved areas, such as clearly and strongly defined guidelines to perform EMG measurements (e.g., how to elaborate with surface EMG limits) or guidelines for the use of exact muscle models.
... 17 In addition to traditional resistance training, the use of supra-maximal loading (110 %1RM) during the eccentric phase has been shown to be effective in stimulating muscle growth. 13 When using this type of training, a coach should always consider risk versus reward, training age, and apply in very small doses over the course of a periodized plan. In terms of muscle signaling, no correlations have been made on load, but it has been recommended that higher mechanical stress results in greater Akt-mTOR signaling. ...
Article
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The ability to help athletes achieve supreme levels of strength, power and muscle hypertrophy represents an important element in the work of strength and conditioning coaches. Specifically, the development of muscle hypertrophy, or an increase in muscle cross- sectional area (CSA), is often considered one of the most important physiological adaptations for both elite and recreational athletes. An increase in muscle hypertrophy, will not only result in an increase in lean muscle mass (i.e. sarcomeres in parallel), but will ideally result in an increase in strength.28,31,38 It should be noted that an increase in hypertrophy does not always result in equivalent strength gains, and strength gains do not always result in equivalent hypertrophy. This is seen in the comparable hypertrophy of Type I and II fibers in elite Bodybuilders and preferential hypertrophy of Type II fibers in elite Power and Olympic Lifters.7 Within the elite athlete population, increased strength will ideally accompany increased muscle hypertrophy, unless of course an athlete plays a sport that requires non-functional (i.e. increased CSA without sustained or increased levels of relative strength) hypertrophy, (eg. American Football Lineman, Sumo Wrestlers, and Bodybuilding).28 Therefore, when developing elite athletes, the optimal training protocols and periodization strategies should be used to enhance functional hypertrophy, or an increase in relative strength with an increase in muscle CSA.26 The goal of this brief review, is to examine the physiological mechanisms behind muscle growth, differentiate between functional and non-functional hypertrophy, and present a model for the development of optimal muscle hypertrophy in the off- season of an elite athlete.
... Relatively few studies have investigated muscle activation when performing dynamic upper body resistance training at different loading intensities. Keogh et al. [10] recruited 12 young experienced lifters to perform the bench press using a variety of training methods including conditions with intensities of 55% and 85% 1RM to failure. Results showed that mean concentric EMG activity of the pectoralis major was significantly higher during the heavy load condition by ∼18%, 19%, and 12%, for the first, middle, and last repetition, respectively. ...
Article
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OBJECTIVE: The purpose of this study was to compare activation of the upper body musculature during the barbell bench press at varying training intensities. METHODS: Twelve young, resistance-trained men performed sets of the bench press to momentary muscular failure with two different loads: a high-load (HIGH) set at 80% of 1RM and a low-load (LOW) set at 50% 1RM. Exercise order was counterbalanced so that half the subjects performed the LOW condition first and the other half performed the HIGH first. Surface elec-tromyography (EMG) was used to assess mean, peak, and iEMG muscle activation of the anterior deltoid, triceps brachii, and sternal and clavicular heads of the pectoralis major. RESULTS: The main effects for trials were significant for mean EMG (p < 0.001) and iEMG matched (p < 0.001) favoring HIGH and iEMG total favoring LOW (p = 0.001) across all muscle groups in both conditions with varying effect sizes. All other main effects and interactions were not statistically significant. CONCLUSION: Despite similarities in peak EMG amplitude, the greater results for mean and iEMG matched in HIGH suggests that heavier loads may produce greater muscle activation.
... Specifically, the use of the umbrella term "cluster set" has evolved to include many different types of set structures that simply describe a manner in which repetitions are performed which diverges from the TS structure. Although Byrd et al. (17), Rooney et al. (80), and Keogh et al. (51) used protocols inclusive of various IRR periods, the first use of the term "cluster set" in the scientific literature, to our knowledge, was used in 2003 (33). That article created a CS by breaking a single TS of 5 repetitions into a single CS of 5 repetitions with short IRR periods. ...
Article
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When performing a set of successive repetitions, fatigue ensues and the quality of performance during subsequent repetitions contained in the set decreases. Oftentimes, this response may be beneficial, as fatigue may stimulate the neuromuscular system to adapt, resulting in a super-compensatory response. However, there are instances in which accumulated fatigue may be detrimental to training or performance adaptations (i.e. power development). In these instances, the ability to recover and maintain repetition performance would be considered essential. By providing intermittent rest between individual repetitions or groups of repetitions within a set, an athlete is able to acutely alleviate fatigue, allowing performance to remain relatively constant throughout an exercise session. Within the scientific literature, a set that includes intermittent rest between individual repetitions or groups of repetitions within a set is defined as a cluster set. Recently, cluster sets have received more attention as researchers have begun to examine the acute and chronic responses to this relatively novel set structure. However, much of the rest-period terminology within the literature lacks uniformity and many authors attempt to compare largely different protocols with the same terminology. Additionally, the present body of scientific literature has mainly focused on the effects of cluster sets on power output, leaving the effects of cluster sets on strength and hypertrophy relatively unexplored. Therefore, the purpose of this review is to further delineate cluster set terminology, describe the acute and chronic responses of cluster sets, and explain the need for further investigation of the effects of cluster sets.
... Total volume completed was recorded on each training day. Neural 1 3 weight, eccentric action, slow-motion, breakdowns, and maximal power training, have been used in an effort to produce maximal gains (Keogh et al. 1999). A new technique that has not been extensively studied is the rest-pause method. ...
... E' stata scelta la panca piana come strumento dello studio perché ricerche condotte dimostrano che durante un sollevamento alla panca piana, la sbarra subisce sia spostamento verticale che orizzontale, e che con carichi pesanti, il punto critico si verifica relativamente presto nella fase concentrica (Madsen et al.: 1984;Wilson et al.: 1989;Keogh et al.: 1999). ...
Thesis
Background: The effectiveness of Slow Series Method (SSM) of training has been always topic of discussion between the experts in the field of training science. Authors such as Alberti (Alberti et al. 2006) affirm that the SSM is a valid approach to increase maximal strength, while others (Hunter et al. 2003) affirm that this training methodology is not better than a traditional resistance training. Aim and Hypothesis: Evaluating the effectiveness of the SSM for increasing maximal strength of the chest muscles comparing it with another traditional resistance training, taking into account the same time under tension (TUT) for both trainings. My hypothesis was that the improvement gained with the SSM are not due to an intrinsic effectiveness of the training itself but comes from an increasing in the total TUT. Method: 16 males trained for 8 weeks and had been separated in two groups: Control Group (Age: 22.5±7.5yo, Weight: 72.8±11.2kg, Height: 177±14cm) performed 6 sets with 15 repetitions each (3” eccentric phase, 1” concentric phase), and Training Group (Age: 23.1±6.9yo, Weight: 69.0±10.3kg, Height: 175±9cm) performed 6 sets with 6 repetitions each (5” eccentric phase, 5” concentric phase). The TUT in both group during each set was equal to 1’ and the rest between each set was 2’30”. The test to assess the maximal lifted load has been performed one week prior the start of the training, 4 weeks after the start of the program and at the end of the eighth week of training. The exercise and the test have been executed on a flat bench press. During the execution of the movement, every subject has been assisted by a partner. Results: A two-way ANOVA reports no statistical difference between groups (p = 0.171), but the training caused significant (p < 0.05) increases in the maximal lifted load in both groups. Conclusion: Results from this study suggest that SSM has no better effect on increasing the maximal strength when compared with another technique that takes the same TUT.
... Deloaded (less than body weight) squat variations can decrease the joint loading while still providing a training stimulus and may be ideal for a player going through a growth spurt. We have used functional isometric training (25) to help provide a greater training stimulus safely in this group. Both deloaded and isometric squat variations have been recommended previously, and an additional emphasis on stability and mobility within the regressed movement skill would also be appropriate for this age group (28). ...
Article
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DESPITE THE RAPID GROWTH IN WOMEN AND GIRLS PLAYING SOCCER, EVIDENCE-BASED GUIDELINES TO INFORM CONDITIONING FOR GIRLS ARE SPARSE. MOST RESEARCH ON YOUTH SOCCER IS CONDUCTED IN MALES, WHICH MAY NOT BE TRANSFERABLE TO PRACTICE IN FEMALE TEAMS. THIS ARTICLE REFLECTS ON THE CURRENT EVIDENCE BASE AND DRAWS ON THE AUTHORS' EXPERIENCES TO PROVIDE GUIDELINES TO IMPROVE CONDITIONING PROGRAMS THROUGHOUT MATURATION IN GIRLS. THE ARTICLE FOCUSES ON THE INTEGRATION OF NEUROMUSCULAR AND METABOLIC CONDITIONING METHODS TO SAFELY IMPROVE PHYSICAL PERFORMANCE AND REDUCE INJURY RISK FACTORS. GUIDELINES ARE PRESENTED FOR PLAYERS PRE, CIRCUM, AND POST PEAK HEIGHT VELOCITY.
... Nella letteratura sull'allenamento di resistenza l'affaticamento muscolare è stato proposto come il fattore chiave per l'ottenimento della forza e degli adattamenti dell'ipertrofia. In questi studi la fatica è stata presa in considerazione sotto due aspetti: 1) influenza dell'affaticamento muscolare sul sistema neuromuscolare per una progressiva riduzione dell'attivazione volontaria della muscolatura durante l'esercizio (affaticamento centrale) e 2) affaticamento correlato ai sottoprodotti metabolico (H+, acido lattico, Pi, Cr, K+) che si accumulano sia all'interno che all'esterno delle fibre muscolari; l'accumulo di questo metaboliti è associato a dolore e disagio [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] . Rooney et al. 22 hanno comparato l'affaticamento e il non affaticamento in un programma di allenamento con ripetizioni continue rispetto all'allenamento con 30 s di riposo tra le ripetizioni, durante un periodo di sei settimane in soggetti non allenati. ...
Article
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Aim. The purpose of this study was to examine neuromuscular fatigue and metabolic demands in response to two different heavy resistive loading patterns. Methods. Nine soccer player amateurs (age=21.55±2.87 years, height=179±0.3 cm, and BF%=7.5±5.64) completed a single session of arm preacher curl (elbow flexion) with two different resistance exercise loading patterns after a six-week preliminary training phase (anatomical adaptation period). In Flat Pyramid Loading Pattern (FPLP), subjects started with a set of 80% 1RM, followed by four fixed sets at 90% 1RM, then finished with a set at 80% 1RM. In Skewed Pyramid Loading Pattern (SPLP), subjects started with a set at 80% 1 RM, followed by incremental three sets at 85%, 90% and 95% 1 RM, then finished with a set at 80% 1 RM. Volume load (total repetitions and relative training load) was equated in both protocols while, the time the muscle was under tension (TUT) in SPLP protocol was greater than FPLP protocol. Maximal Voluntary Isometric Contraction (MVIC) and blood lactate were assessed pre-protocol and post-protocol to determine the acute neuromuscular fatigue and metabolic demands.Results. The results showed that MVIC significantly decreased from 39.14±7.81 to 29.71±7.08 (kg) and from 39.75±9.41 to 28.87±7.47 (kg) after the SPLP and FPLP protocols, respectively (P<O.05). No significant change was observed in blood lactate in both groups after SPLP and FPLP protocols (P<O.05). Conclusion. In conclusion, the results indicate that different heavy resistance loading patterns cause same neuromuscular fatigue and metabolic demands when the volume load, total repetitions and relative training load are equated.
... Since a submaximal load can be either lifted more slowlyor faster, the maximal voluntary effort for any given load is required; otherwise results can be very different. Electromyographic observations have showed, indeed, a significantly lower concentric force when a submaximal load is intentionally lifted at a slower velocity (20). The concrete risk is that, as the load gets heavier, the subject may naturally increase his effort in lifting it. ...
Article
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The mathematical relationship between the force and the velocity as determined during isoinertial progressive resistance strength tests is being extensively used for the assessment of neuromuscular qualities and for a targeted resistance training. The reliability of this relationship depends on the reliability of the collected force and velocity values. This reliability can be jeopardized by several factors such as: 1) an erroneous movement execution; 2) an improper load assignment; 3) a useless number of performed repetitions; 4) an inadequate rest interval between sets of repetitions; 5) an improper use of the measurement device and of the relevant computing methods. The aim of this contribution is to provide the operator with a list of good practice rules retrieved from the specific scientific literature concerning the instrumented assessment of muscle strength during isoinertial resistance exercises.
... The skin was prepared prior to the placement of each electrode by shaving and light abrasion of the skin followed by cleansing with an isopropyl alcohol swab. A permanent marker pen was used to mark and identify the position of each electrode in order to minimize electrode placement variability from session to session (Giaconcomi et al., 2005;Keogh et al., 1999). Eight single-square-wave electrical impulses (100 µs) were delivered during the 8-s sampling period. ...
Poster
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Muscle force production and power output in active males, regardless of the site of measurement (hand, leg, or back), are higher in the evening than in the morning. This diurnal variation is attributed to motivational, peripheral and central factors, and higher core and, possibly, muscle temperatures in the evening. This study investigated whether increasing morning rectal temperatures to evening resting values, by active or passive warm-ups, leads to muscle force production and power output becoming equal to evening values in motivated subjects. Ten healthy active males (mean ± SD: age, 21.2 ± 1.9 yrs; body mass, 75.4 ± 8 kg; height, 1.76 ± .06 m) completed the study, which was approved by the University Ethics Committee. The subjects were familiarized with the techniques and protocol and then completed four sessions (separated by at least 48 h): control morning (07:30 h) and evening (17:30 h) sessions (with an active 5-min warm-up) and then two further sessions at 07:30 h but proceeded by an extended active or passive warm-up to raise rectal temperature to evening values. These last two sessions were counterbalanced in order of administration. During each trial, three measures of handgrip strength, isokinetic leg strength measurements (of knee flexion and extension at 1.05 and 4.19 rad.s(-1) through a 90° range of motion), and four measures of maximal voluntary contraction (MVC) on an isometric ergometer (utilizing the twitch-interpolation technique) were performed. Rectal and intra-aural temperatures, ratings of perceived exertion (RPE) and thermal comfort (TC) were measured. Measurements were made after the subjects had reclined for 30 min and after the warm-ups and prior to the measurement of handgrip and isokinetic and isometric ergometry. Muscle temperature was taken after the warm-up and immediately before the isokinetic and MVC measurements. Warm-ups were either active (cycle ergometer at 150 W) or passive (resting in a room at 35 °C, relative humidity 45%). Data were analyzed using analysis of variance models with repeated measures. Rectal and intra-aural temperatures were higher at rest in the evening (.56 °C and .74 °C; p < .05) than in the morning, but there were no differences after the active or passive warm-ups, the subjects' ratings of thermal comfort reflecting this. Muscle temperatures also displayed significant diurnal variation, with higher values in the evening (~.31 °C; p < .05). Grip strength, isokinetic knee flexion for peak torque and peak power at 1.05 rad.s(-1), and knee extension for peak torque at 4.19 rad.s(-1) all showed higher values in the evening. All other measures of strength or power showed a trend to be higher in the evening ( .10 > p > .05). There was no significant effect of active or passive warm-ups on any strength or power variable, and subjects reported maximal values for effort for each strength measure. In summary, effects of time of day were seen in some measures of muscle performance but, in this population of motivated subjects, there was no evidence that increasing morning rectal temperature to evening values by active or passive warm-up increased muscle strength to evening values.
... The skin was prepared prior to the placement of each electrode by shaving and light abrasion of the skin followed by cleansing with an isopropyl alcohol swab. A permanent marker pen was used to identify the position of each electrode in order to minimize electrode placement variability between sessions Keogh et al., 1999). Eight single square-wave electrical impulses (100 ms) were delivered during the 8-s sampling period. ...
Article
Full-text available
Muscle force production and power output in active males, regardless of the site of measurement (hand, leg, or back), are higher in the evening than the morning. This diurnal variation is attributed to motivational, peripheral, and central factors and higher core and, possibly, muscle temperatures in the evening. This study investigated whether decreasing evening resting rectal temperatures to morning values, by immersion in a water tank, leads to muscle force production and power output becoming equal to morning values in motivated subjects. Ten healthy active males (mean ± SD: age, 22.5 ± 1.3 yrs; body mass, 80.1 ± 7.8 kg; height, 1.72 ± 0.05 m) completed the study, which was approved by the local ethics committee of the university. The subjects were familiarized with the techniques and protocol and then completed three sessions (separated by at least 48 h): control morning (07:30 h) and evening (17:30 h) sessions (with an active 5-min warm-up on a cycle ergometer at 150 W) and then a further session at 17:30 h but preceded by an immersion in cold water (~16.5 °C) to lower rectal temperature (Trec) to morning values. During each trial, three measures of grip strength, isokinetic leg strength measurements (of knee flexion and extension at 1.05 and 4.19 rad s(-1) through a 90° range of motion), and three measures of maximal voluntary contraction (MVC) on an isometric dynamometer (utilizing the twitch-interpolation technique) were performed. Trec, rating of perceived exertion (RPE), and thermal comfort (TC) were also measured after the subjects had reclined for 30 min at the start of the protocol and prior to the measures for grip, isokinetic, and isometric dynamometry. Muscle temperature was taken after the warm-up or water immersion and immediately before the isokinetic and MVC measurements. Data were analyzed using general linear models with repeated measures. Trec values were higher at rest in the evening (by 0.37 °C; p < 0.05) than the morning, but values were no different from morning values immediately after the passive pre-cooling. However, Trec progressively decreased throughout the experiments, this being reflected in the subjects' ratings of thermal comfort. Muscle temperatures also displayed significant diurnal variation, with higher values in the evening (by 0.39 °C; p < 0.05). Right grip strength, isometric peak power, isokinetic knee flexion and extension for peak torque and peak power at 1.05 rad s(-1), and knee extension for peak torque at 4.19 rad s(-1) all showed higher values in the evening (a range of 3-14%), and all other measures of strength or power showed a statistical trend to be higher in the evening (0.10 > p > 0.05). Pre-cooling in the evening significantly reduced force or power variables towards morning values. In summary, effects of time of day were seen in some measures of muscle performance, in agreement with past research. However, in this population of motivated subjects, there was evidence that decreasing evening Trec to morning values by coldwater immersion decreased muscle strength to values similar to those found in the morning. It is concluded that diurnal changes in muscle performance are linked to diurnal changes in Trec.
... • Intentional 5 slow velocity contractions are used with submaximal loads where the individual has greater control of the velocity. It has been shown that concentric force production was significantly lower for an intentionally slow velocity (5s concentric, 5s eccentric) of lifting compared with a traditional (moderate) velocity with a corresponding lower neural activation 6 . These data suggest that motor unit activity may be limited when intentionally contracting at a slow velocity. ...
... In particular, numerous studies have demonstrated that partial repetitions, whereby the load is lifted only through a limited part of the ROM in an exercise, is effective at increasing strength at approximately ±10-20 • from the trained joint angle [62,63]. Similarly, functional isometrics which involve the application of force by the trainee against a load against a practically immovable obstacle (e.g. the pushing of a barbell against pins in a power rack) [64] have been shown to be successful at increasing strength at the specifically trained ROM [65,60,61,66]. ...
Article
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In the context of resistance training the so-called "sticking point" is commonly understood as the position in a lift in which a disproportionately large increase in the difficulty to continue the lift is experienced. If the lift is taken to the point of momentary muscular failure, the sticking point is usually where the failure occurs. Hence the sticking point is associated with an increased chance of exercise form deterioration or breakdown. Understanding the mechanisms that lead to the occurrence of sticking points as well as different training strategies that can be used to overcome them is important to strength practitioners (trainees and coaches alike) and instrumental for the avoidance of injury and continued progress. In this article we survey and consolidate the body of existing research on the topic: we discuss different definitions of the sticking point adopted in the literature and propose a more precise definition, describe different muscular and biomechanical aspects that give rise to sticking points, and review the effectiveness of different training modalities used to address them.
... This might be because of repeated acute exposure to high levels of growth hormone. Keogh et al. (11) advocated the ''breakdown'' approach when training for hypertrophy. With this ap-proach, the first set is performed at a relatively high intensity (e.g., 85% of 1RM), and then the intensity is gradually reduced over subsequent sets to sustain consistent repetitions, with 30-60 seconds rest between sets. ...
Article
Research has indicated that multiple sets are superior to single sets for maximal strength development. However, whether maximal strength gains are achieved may depend on the ability to sustain a consistent number of repetitions over consecutive sets. A key factor that determines the ability to sustain repetitions is the length of rest interval between sets. The length of the rest interval is commonly prescribed based on the training goal, but may vary based on several other factors. The purpose of this review was to discuss these factors in the context of different training goals. When training for muscular strength, the magnitude of the load lifted is a key determinant of the rest interval prescribed between sets. For loads less than 90% of 1 repetition maximum, 3-5 minutes rest between sets allows for greater strength increases through the maintenance of training intensity. However, when testing for maximal strength, 1-2 minutes rest between sets might be sufficient between repeated attempts. When training for muscular power, a minimum of 3 minutes rest should be prescribed between sets of repeated maximal effort movements (e.g., plyometric jumps). When training for muscular hypertrophy, consecutive sets should be performed prior to when full recovery has taken place. Shorter rest intervals of 30-60 seconds between sets have been associated with higher acute increases in growth hormone, which may contribute to the hypertrophic effect. When training for muscular endurance, an ideal strategy might be to perform resistance exercises in a circuit, with shorter rest intervals (e.g., 30 seconds) between exercises that involve dissimilar muscle groups, and longer rest intervals (e.g., 3 minutes) between exercises that involve similar muscle groups. In summary, the length of the rest interval between sets is only 1 component of a resistance exercise program directed toward different training goals. Prescribing the appropriate rest interval does not ensure a desired outcome if other components such as intensity and volume are not prescribed appropriately.
... Research indicates that intentionally performing repetitions in a very slow manner does not provide an adequate stimulus for complete activation of a muscle's motor unit pool. Employing a within-subject design, Keogh et al. [22] recruited 12 young experienced lifters to perform one set of the bench press using a variety of training methods including a very slow cadence and a traditional cadence. The slow lifting condition performed the exercise at 55 % of 1 RM for a total duration of 10 s per repetition (5 s for both concentric and eccentric actions); the traditional training condition was performed at *85 % of 1 RM with the intent to lift the weight as fast as possible. ...
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Maximizing the hypertrophic response to resistance training (RT) is thought to be best achieved by proper manipulation of exercise program variables including exercise selection, exercise order, length of rest intervals, intensity of maximal load, and training volume. An often overlooked variable that also may impact muscle growth is repetition duration. Duration amounts to the sum total of the concentric, eccentric, and isometric components of a repetition, and is predicated on the tempo at which the repetition is performed. We conducted a systematic review and meta-analysis to determine whether alterations in repetition duration can amplify the hypertrophic response to RT. Studies were deemed eligible for inclusion if they met the following criteria: (1) were an experimental trial published in an English-language refereed journal; (2) directly compared different training tempos in dynamic exercise using both concentric and eccentric repetitions; (3) measured morphologic changes via biopsy, imaging, and/or densitometry; (4) had a minimum duration of 6 weeks; (5) carried out training to muscle failure, defined as the inability to complete another concentric repetition while maintaining proper form; and (6) used human subjects who did not have a chronic disease or injury. A total of eight studies were identified that investigated repetition duration in accordance with the criteria outlined. Results indicate that hypertrophic outcomes are similar when training with repetition durations ranging from 0.5 to 8 s. From a practical standpoint it would seem that a fairly wide range of repetition durations can be employed if the primary goal is to maximize muscle growth. Findings suggest that training at volitionally very slow durations (>10s per repetition) is inferior from a hypertrophy standpoint, although a lack of controlled studies on the topic makes it difficult to draw definitive conclusions.
... Keogh et al. (82) reported a cross-sectional comparison of force, power, EMG, time under tension, and lactate response to eight different bench press techniques performed on a plyometric power system. Keogh et al. (82) suggested that supra-maximal eccentric muscle actions (~six 4-second eccentric-only repetitions with 110 % concentric 1 RM) impose a greater overload than heavy weight training (6 RM) on the musculature. ...
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JEPonline 2004;7(3):1-60. In February 2002, the American College of Sports Medicine (ACSM) published a Position Stand entitled Progression Models in Resistance Training for Healthy Adults. The ACSM claims that the programmed manipulation of resistance-training protocols such as the training modality, repetition duration, range of repetitions, number of sets, and frequency of training will differentially affect specific physiological adaptations such as muscular strength, hypertrophy, power, and endurance. The ACSM also asserts that for progression in healthy adults, the programs for intermediate, advanced, and elite trainees must be different from those prescribed for novices. An objective evaluation of the resistance-training studies shows that these claims are primarily unsubstantiated. In fact, the preponderance of resistance-training studies suggest that simple, low-volume, time-efficient, resistance training is just as effective for increasing muscular strength, hypertrophy, power, and endurance—regardless of training experience—as are the complex, high-volume, time-consuming protocols that are recommended in the Position Stand. This document examines the basis for many of the claims in the Position Stand and provides an objective review of the resistance training literature.
... Keogh, et al. 16 considered acute muscle activation of RP training compared to heavy weight training (HWT-defined as 6-repetition maximum (RM)). They described RP training as normal isoinertial concentric actions, followed by 2 second unloaded rest period at the end of each contraction. ...
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Aim: This study examined low volume resistance training (RT) in trained participants with and without advanced training methods. Methods: Trained participants (RT experience 4+3 years) were randomised to groups performing single set RT;; ssRM (n = 21) performing repetitions to self--determined repetition maximum (RM), ssMMF (n = 30) performing repetitions to momentary muscular failure (MMF), and ssRP (n = 28) performing repetitions to self--determined RM using a rest pause (RP) method. Each performed supervised RT 2x/week for 10 weeks. Outcomes included maximal isometric strength and body composition using bioelectrical impedance analysis. Results: The ssRM group did not significantly improve in any outcome. The ssMMF and ssRP groups both significantly improved strength (p < 0.05). Magnitude of changes using effect size (ES) was examined between groups. Strength ES's were considered large for ssMMF (0.91 to 1.57) and ranging small to large for ssRP (0.42 to 1.06). Body composition data revealed significant improvements (p < 0.05) in muscle and fat mass and percentages for whole body, upper limbs and trunk for ssMMF, but only upper limbs for ssRP. Body composition ES's ranged moderate to large for ssMMF (0.56 to 1.27) and ranged small to moderate for ssRP (0.28 to 0.52). ssMMF also significantly improved (p < 0.05) total abdominal fat and increased intracellular water with moderate ES's (--0.62 and 0.56 respectively). Conclusion: Training to self--determined RM is not efficacious for trained participants. Training to MMF produces greatest improvements in strength and body composition, however, RP style training does offer some benefit.
... Em relação à resposta da FC durante os exercícios físicos, alguns estudos têm demonstrado não existir relação linear entre a FC e o VO 2 em exercícios físicos com solicitação simultânea de braços e pernas, como, por exemplo, a ginástica aeróbica e o step training (15,(23)(24)(25) . Contudo, nas atividades cíclicas, corrida ou caminhada que utilizam predominantemente os membros inferiores, a relação linear existente entre a FC e o consumo de oxigênio aumenta significativamente, mas dependem de diversas considerações anatômicas e fisiológicas (26)(27)(28) . ...
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Jump Fit lessons further the improvement of the general physical fitness through choreographies performed on an elastic surface with rhythm and movements variation with intervals and low impact. However, not much is known about the actual energetic expenditure and the behavior of the metabolic variables related to Jump Fit lessons. The objective of this study was to identify and to evaluate the behavior of the functional variables such as: heart rate (HR), oxygen intake (VO2), metabolic equivalent (MET) and energetic expenditure through routine spirometry measurement of a Jump Fit lesson. The tests were performed in four visits by 10 women who practice Jump Fit with age of 26.8 (± 7.2), body mass of 57.6 kg (± 6.8) and height of 162.2 cm (± 3.9). The spirometric evaluation of the several stages of the lesson revealed the following average results: HR of 160.3 bpm (± 8.9), VO2 of 1.59 L.min-1 (± 0.45), RQ 0.87 (± 0.10) and total energetic expenditure of 386.4 kcal (± 13.8). The Jump Fit lesson average intensity corresponded to 75% (± 7.7) of the VO2peak. For the analysis of the metabolic variables behavior in the different stages of the lessons, the results were treated through ANOVA for repeated measures with Bonferroni verification. The t-test was used to identify if differences between the functional responses in rest and EPOC phases occurred. The level of significance of p < 0.05 was adopted. It was concluded that from the magnitude of the functional responses, the Jump Fit lesson provides increase on the cardiorespiratory resistance, thus contributing effectively for the maintenance and improvement of the physical fitness and health in quality of life.
... However, if training volume is defined according to the guidelines by Wilk et al. [12,13] based on TUT, the use of slow movement tempo allows the athlete to significantly extend TUT and, consequently, increase training volume. Longer time of sustained muscle tension in a set can be also useful in evoking muscle hypertrophy [15,16] which can be linked to e.g. the fact that slow movement extends the time under tension without the relaxation phase [17,18]. ...
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ABSTRACT: The main aim of this study was to determine whether the level of experience in strength training has a significant effect on differences in the value of exercise volume determined on time under tension (TUT) and number of repetition (REP) for a specific movement tempo. The study examined 68 men divided into groups of beginners and advanced strength trained athletes. The participants performed 5 sets of bench press (BP) at 70% 1RM using either a REG, MED or SLOW metronome guided cadence. Each set was performed to failure and with 3 min of rest between sets. Significant differences in TUT were found between the groups of beginners and advanced athletes for the slow (SLO) 6/0/4/0 tempo in set 1 (p = 0.01) and set 2 (p = 0.04), and for the regular (REG) 2/0/2/0 tempo in set 5 (p = 0.01). Significant differences were documented for total TUT between the beginners and advanced athletes for the SLO 6/0/4/0 tempo (p = 0.04). The results of ANOVA revealed significant differences in the number of repetitions between groups for the SLO 6/0/4/0 tempo in set 4 (p = 0.04) and set 5 (p = 0.04), and for the REG 2/0/2/0 tempo in set 5 (p = 0.01). The main finding of this study is that strength training experience has a significant effect on training volume, both in terms of TUT and REP at a specific constant movement tempo. Significant differences do not occur for each value of the tempo used.
... The results of our analysis showed no difference in peak EMG between movements performed with different movement velocities, but higher mean EMG values were obtained during slower movements. This confirms our hypotheses, but is in contrast with previous studies using TRT, where higher levels of muscle activation were obtained with increasing velocity [20,25,26]. We acknowledge that none of the velocities used in the present study can be classified as "fast", since the participants took four to eight seconds to complete a repetition; however, differences between controlled movements (2.8 vs. 5.6 s per repetition) have been previously reported by Sakamoto & Sinclair [20]. ...
Article
Objectives: To explore the acute effects of training status, movement velocity, dominance, and visual feedback on muscle activation and rating of perceived exertion (RPE) during resistance training with no external load (no-load resistance training; NLRT). Methods: Thirty-three men (17 untrained and 16 trained), performed elbow flexions in four NLRT sessions: 1) slow velocity with EMG visual feedback, 2) slow velocity without EMG visual feedback, 3) fast velocity with EMG feedback, and 4) fast velocity without EMG feedback. RPE was measured using the Borg Discomfort scale. EMG for the biceps and triceps were recorded for both arms. Results: EMG feedback had no influence on RPE. The peak and mean EMG values were not different for the biceps (93.8±11.5% and 50±13.1%) and triceps (93.7±23.9% and 49.6±16.2%). The results revealed a difference in the training status, with higher peak EMG for untrained than for trained participants (96.9±20% vs. 90.2±15.6%). However the values for mean EMG were not different between the untrained and trained (50.3±15.7% vs. 49.2±13.7%) participants. There was no difference in the peak (92.8±19% vs. 94.7±20.4%) and mean (49.8±15.0% vs. 49.7±14.5%) EMG values for the dominant and non-dominant sides. Peak EMG values were not different between faster and slower velocities (93.6±19.6% and 93.9±17.8%). However, mean EMG was higher for slower (50.5±14.4%) than for faster (48.5±15.4%) velocities. The peak and mean EMG during contractions with (93.3±17.5% and 49.5±14.1%) and without visual feedback (94.2±19.9% and 50±15.4%) were not significantly different. Conclusion: NLRT produces high levels of muscle activation independent of training, status, dominance, movement velocity, and visual feedback.
... T he bench press is one of the foundational exercises used to develop upper-body pushing strength in athletes (1,18,28) and is also used to encourage muscle hypertrophy in the upper body (25). The exercise is relatively easy to perform and can be taught to most individuals. ...
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THE CLOSE-GRIP BENCH PRESS HAS RECEIVED LIMITED ANALYSIS IN THE PROFESSIONAL LITERATURE. THEREFORE, THIS ARTICLE WILL REVIEW THE EXISTING LITERATURE THAT DOCUMENTS THE TECHNIQUE, MUSCLE ACTIVATION CHANGES THAT OCCUR WHEN PERFORMING THIS EXERCISE, AND THE RESULTING IMPLICATIONS. THIS RELATES TO POTENTIAL HYPERTROPHY AND STRENGTH ADAPTATIONS THAT MAY RESULT FOR MUSCLES INVOLVED IN ELBOW EXTENSION (E.G., TRICEPS BRACHII) AND ARM FLEXION (E.G., PECTORALIS MAJOR), AS WELL AS SPORT-SPECIFIC POWER ADAPTATIONS. THE BENEFITS OF USING A CLOSER GRIP DURING THE BENCH PRESS FOR CERTAIN INDIVIDUALS WILL BE ACKNOWLEDGED. LAST, THE EXECUTION OF THIS EXERCISE (STARTING POSITION, BAR DESCENT, AND BAR ASCENT) WILL BE DETAILED.
... Total volume completed was recorded on each training day. Neural 1 3 weight, eccentric action, slow-motion, breakdowns, and maximal power training, have been used in an effort to produce maximal gains (Keogh et al. 1999). A new technique that has not been extensively studied is the rest-pause method. ...
Article
Purpose: Rest-pause (4-s unloaded rest between repetitions) training effects on one repetition maximum (1 RM), lifting volume, and neural activation via electromyography (EMG) are currently vague in the literature and can benefit strength and conditioning professionals for resistance training programme design. Therefore, this study compared 1 RM, neural activation via (EMG), and volume differences between rest-pause vs. traditional resistance training. Methods: Trained males (N = 20) were randomly assigned to either a rest-pause or a traditional training group. Pre- and post-1 RM testing was recorded. Training sessions were completed twice a week for 4 weeks and consisted of four sets of bench press to volitional fatigue at 80% of pre-test 1 RM with a 2-min rest between sets. Total volume completed was recorded on each training day. Neural activation of the pectoralis major was measured on the first and last training days. Results: A two-way repeated-measures ANOVA indicated both groups significantly increased their 1 RMs following the 4-week training protocol (p < .05). However, no significant differences were found in 1 RM and neural activation between the two groups (p > .05). An independent samples t test indicated that total volume lifted was significantly higher for the rest-pause group (56,778 vs. 38,315 lbs; p < .05) throughout the protocol and independently during weeks 2, 3, and 4. Conclusions: While strength and neural activation changes did not differ between groups, both increased 1 RMs and the rest-pause group achieved greater increases in volume than the traditional group. If volume is the focus of training, the rest-pause method should be utilized.
... The measure of muscle activation is often given by the EMG amplitude and during bench press exercise it has been calculated by the root mean square (RMS) (Clark et al., 2011;Sakamoto and Sinclair, 2012;Snyder and Fry, 2012), integral (area under the curve) (Keogh et al., 1999;Ojasto and Hakkinen, 2009) and/or by peak amplitude (Calatayud et al., 2016(Calatayud et al., , 2015Keogh et al., 1999;Schoenfeld et al., 2016). ...
Article
The present study compared neuromuscular activation, measured by surface electromyography (EMG) amplitude [measure by EMG peak (EMGPEAK)] and range of motion (ROM) where EMGPEAK occurred between two training protocols, matched by time under tension, but with a different number and duration of repetitions. Sixteen recreationally trained males performed 2 training protocols with 3 sets, 180 s of rest with 60% of one-repetition maximum(1RM) on the bench press performed in a Smith machine. Protocol A consisted of 6 repetitions with a repetition duration of 6s and protocol B consisted of 12 repetitions with a repetition duration of 3s. EMG activity of anterior deltoid, pectoralis major and triceps brachii muscles were recorded. The results showed a general higher EMG amplitude (regardless of the muscle) in protocol B (p= 0.010), and pectoral and triceps brachii consistently presented higher neuromuscular activation than anterior deltoid at both protocols (p= 0.007). Additionally, the ROM where EMGPEAK occurred in triceps brachii was in the middle of the concentric action (~50% of ROM), this occurred in the first half of the same action (~24% of ROM) in the other muscles. In conclusion, protocol B demonstrated an increased EMG amplitude over protocol A, although both protocols responded similarly by achieving the highest EMG amplitude at same ROM among the muscles analysed.
... However, slower RT movement speeds are expected to occur toward the end of a set as fatigue occurs (Mookerjee & Ratamess, 1999). Slower movement speeds may also be a preferred strategy during RT because they allow for greater control of the resistance and may have a beneficial effect on muscle hypertrophy (Bird, Tarpenning, & Marino, 2005;Keogh, Wilson, & Weatherby, 1999). Whether it is the focus of the RT program or due to fatigue, the speed of movement may vary during a RT workout. ...
Article
Speed of movement has been shown to affect the validity of physical activity (PA) monitors during locomotion. Speed of movement may also affect the validity of accelerometer-based PA monitors during other types of exercise. Purpose : To assess the ability of the Atlas Wearables Wristband2 (a PA monitor developed specifically for resistance training [RT] exercise) to identify the individual RT exercise type and count repetitions during RT exercises at various movement speeds. Methods : 50 male and female participants completed seven sets of 10 repetitions for five different upper/lower body RT exercises while wearing a Wristband2 on the left wrist. The speed of each set was completed at different metronome-paced speeds ranging from a slow speed of 4 sec·rep ⁻¹ to a fast speed of 1 sec·rep ⁻¹ . Repeated Measures ANOVAs were used to compare the actual exercise type/number of repetitions among the seven different speeds. Mean absolute percent error (MAPE) and bias were calculated for repetition counting. Results : For each exercise, there tended to be significant differences between the slower speeds and the fastest speed for activity type identification and repetition counting ( p < .05). Across all exercises, the highest accuracy for activity type identification (91 ± 1.8% correct overall), repetition counting (8.77 ± 0.17 of 10 reps overall) and the lowest MAPE (14 ± 1.7% overall) and bias (−1.23 ± 0.17 reps overall) occurred during the 1.5 sec·rep ⁻¹ speed (the second fastest speed tested). Conclusions : The validity of the Atlas Wearables Wristband2 to identify exercise type and count repetitions varied based on the speed of movement during RT exercises.
... The skin was prepared by shaving and light abrasion for each electrode site. The outline of both electrodes was drawn on to the skin using a permanent marker to minimise variability of electrode placement between sessions (Keogh, Wilson, & Weatherby, 1999). Two paired electrical stimuli (100 Hz) produced by means of square wave impulses (200 Ks) were delivered during a 6 s sampling period. ...
Article
The study assesses the test–retest reliability of movement and physiological measures during a simulated rugby match that employed activities performed in a stochastic order. Twenty male rugby players (21.4 ± 2.1 y) completed two trials of a 2 × 23 min rugby movement simulation protocol during which the order of events was performed in a stochastic order, with 7–10 days between trials. Movement characteristics, heart rate (HR), RPE, maximum voluntary contraction (MVC), voluntary activation (VA%) of the quadriceps, Stroop test and subjective task load rating (NASA-TLX) were measured. The most reliable measures of external load was relative distance (typical error [TE] and CV% = 1.5–1.6 m min⁻¹ and 1.4–1.5%, respectively), with all other movement characteristics possessing a CV% <5%. The most reliable measure of internal load, neuromuscular function and perceptual measures were for %HRmax (TE and CV% = 1.4–1.7% and 1.4–2.1%, respectively), MVC before (TE and CV% = 10.8–14.8 N·m and 3.8–4.6%, respectively), and average RPE (TE and CV% = 0.5–0.8 AU and 3.6–5.5%, respectively). The Stroop test, NASA-TLX and blood lactate produced the least reliable measures (CV% >5%). Future studies can confidently examine changes in several perceptual, neuromuscular, physiological and movement measures related to rugby activity using stochastic movements.
... 20 s), to allow partial recovery to complete the predefined number of repetitions [9]. Other authors suggested using shorter pauses (i.e. 2 s) between repetitions [65]. ...
... Seventeen males with weight training experience and aged between 18 and 30 years (mean 6 SD: age = 23.8 6 2.9 years; height = 1.76 6 0.08 m; mass = 75.1 6 8.6 kg; and 1RM Smith machine bench press = 89.6 6 14.9 kg) participated in this study. The inclusion criteria for participation were (a) currently weight training continuously for at least 6 months before the start of the study; (b) no functional limitations regarding performing the 1RM test or the training protocols; and (c) the ability to lift a weight corresponding to their own body mass on the 1RM Smith machine bench press (27). Subjects were informed about the study objectives, procedures, and risks and freely signed an informed consent form. ...
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Lacerda, LT, Costa, CG, Lima, FV, Martins-Costa, HC, Diniz, RCR, Andrade, AGP, Peixoto, GHC, Bemben, MG, and Chagas, MH. Longer concentric action increases muscle activation and neuromuscular fatigue responses in protocols equalized by repetition duration. J Strength Cond Res 33(6): 1629-1639, 2019-The aim of this study was to investigate the impact of protocols equalized by the repetition duration but composed of different concentric (CON) and eccentric (ECC) durations on muscle activation and neuromuscular fatigue. Seventeen males with previous experience in resistance training performed 3 training protocols (A-2 second CON: 4 second ECC; B-3 second CON: 3 second ECC; and C-4 second CON: 2 second ECC) with the Smith machine bench press exercise, all with 3 sets, 6 repetitions, 3 minutes' rest, and 60% of 1RM. The normalized root mean square of the electromyographic signal (EMG RMS) and mean frequency elec-tromyography (EMG MF) for pectoralis major and triceps brachii muscles were calculated for second and fifth repetitions in each set. The results showed an EMG MF decrease across the repetitions accompanied by a progressive increase of the EMG RMS across the repetitions for all protocols and muscles. The EMG RMS was higher in protocol C when compared with protocol A and B for pectoralis major. The EMG MF was lower in protocols B and C than in protocol A for pectoralis major throughout the sets and repetitions. A higher EMG RMS and a lower EMG MF were observed in protocols B and C compared with protocol A for triceps brachii, solely in the fifth repetition. In conclusion, training protocols conducted with the same repetition duration, but with different concentric and eccentric durations , produce distinct muscle activation and neuromuscular fatigue responses, in which performing longer concentric durations could be the more appropriate strategy to increase muscle activation and neuromuscular fatigue.
... The level of peak power output generated in Set 3 for ECC SLO tempo was significantly lower than in Set 2 . A slower ECC phase of movement reduces power output 35 and diminishes the PAP effect during resistance exercise and is not preferable for power training. Furthermore, the stretchshortening cycle is another mechanism that may explain the obtained results. ...
PURPOSE: Resistance training is one of the key components influencing power output. Previous studies directed at power development through the use of post-activation potentiation (PAP) have analyzed resistance exercises at volitional or fast tempo of movement in the entire cycle. without control of the duration of the concentric and eccentric phases of the movement. To date, no scientific studies have explored the effects of varied movement tempo on the level of power output, velocity and PAP efficiency. METHODS: During the experimental sessions, study participants performed three sets (Sets1-3) of the bench press (BP) exercise using 70% 1RM and two different tempos of movement: 2/0/X/0 eccentric medium tempo (ECCMED), and 6/0/X/0 eccentric slow tempo (ECCSLO). RESULTS: Post-hoc analysis demonstrated significant differences in values of peak (PPEAK) and mean power (PMEAN) between Sets1-3 measured for the ECCMED (2/0/X/0) tempo. The values of PMEAN in Set3 (492.15 ± 87.61 W) were significantly higher than in Set2 (480.05 ± 82.10 W) and Set1 (467.65 ± 79.18 W). Similarly, the results of PPEAK in Set3 (713.10 ± 132.72 W) were significantly higher than those obtained in Set2 (702.25 ± 129.5 W) and Set1 (671.55 ± 115.79 W). For the ECCSLO tempo (6/0/X/0) in Set2 (587.9 ± 138.48 W), the results of PPEAK was significantly higher than in Set1 (565.7 ± 117.37 W) and Set3 (563.1 ± 124.93 W). CONCLUSIONS: The results of this study indicate that the PAP effect is observed, for both, slow and medium tempo of movement.
... Kraemer et al. [29] suggested that sub-maximal loads are used during the performance of resistance exercises with slow contractions in order to obtain greater control of body movement velocity. Indeed, a study has shown that concentric force production was significantly less during a bench press exercise performed with intentionally slow contractions when compared to contractions performed more explosively [85]. However, Keeler et al. [86] reported significantly less strength gains after 10 weeks of training following training with super-slow contractions (10 s concentric:5 s eccentric) compared to slow contractions (2 s concentric:4 s eccentric). ...
Article
Whilst the “acute hypothesis” was originally coined to describe the detrimental effects of concurrent training on strength development, similar physiological processes may occur when endurance training adaptations are compromised. There is a growing body of research indicating that typical resistance exercises impair neuromuscular function and endurance performance during periods of resistance training-induced muscle damage. Furthermore, recent evidence suggests that the attenuating effects of resistance training-induced muscle damage on endurance performance are influenced by exercise intensity, exercise mode, exercise sequence, recovery and contraction velocity of resistance training. By understanding the influence that training variables have on the level of resistance training-induced muscle damage and its subsequent attenuating effects on endurance performance, concurrent training programs could be prescribed in such a way that minimises fatigue between modes of training and optimises the quality of endurance training sessions. Therefore, this review will provide considerations for concurrent training prescription for endurance development based on scientific evidence. Furthermore, recommendations will be provided for future research by identifying training variables that may impact on endurance development as a result of concurrent training.
... Surface electromyography has been extensively used to investigate the pattern of pectoralis major (PM) activation in resistance training studies. Attention is often focused on the effect of exercise variants on PM activation, such as trunk inclination, hand grip distance on the barbell and different training methods (Barnett et al., 1995;Glass and Armstrong, 1997;Gomo and Van Den Tillaar, 2016;Keogh et al., 1999;Lauver et al., 2016;Lehman, 2005;Mookerjee and Ratamess, 1999;Sakamoto and Sinclair, 2012;Snyder and Fry, 2012;Trebs et al., 2010). Notwithstanding such well-conducted research, contradictory findings on the pattern of PM activation have been reported. ...
Article
Changes in innervation zone (IZ) position may affect the amplitude of surface electromyograms (EMGs). If not accounted for, these changes may lead to equivocal interpretation on the degree of muscle activity from EMG amplitude. In this study we ask how much the IZ position changes within different regions of the pectoralis major (PM) during the bench press exercise. If expressive, changes in IZ position may explain the conflictual results reported on PM activation during bench press. Single-differential surface EMGs were collected from 15 regions along the PM cranial, centro-cranial, centro-caudal and caudal fibres, while 11 healthy participants gently, isometrically contracted their muscle. IZs were identified visually, from EMGs collected with the glenohumeral joint at extreme bench press positions; 20° and 110° of abduction in the horizontal plane. Except for 3 out of 88 acquisitions (4 detection sites x 2 glenohumeral angles x 11 participants), for which no phase opposition and action potential propagation were observed, IZs could be well identified. Group results revealed the IZ moved medially from 110° to 20° of glenohumeral joint abduction in the horizontal plane, regardless of the PM region from where EMGs were detected (P<0.01). IZs were confined medially within PM, from ~20% to ~40% of the muscle-tendon unit length, and their position changed up to 13.3%. These results suggest that changes in the amplitude of EMGs detected mainly medially from PM may be not associated with changes in the degree of PM activity during bench press.
... These criteria ensured that the study sample had experience with resistance training. 14 Written informed consent was obtained from all participants. The study was approved by the local Ethics Committee (protocol #0476/13). ...
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Introduction: The literature has shown that a gap is identified regarding the acute effects of blood flow restriction training on aerobic variables. Objective: to analyze oxygen consumption (VO2) during and after two resistance training sessions: traditional high intensity and low intensity with blood flow restriction. Methods: After one-repetition maximum tests, eight male participants (25.7±3 years) completed the two experimental protocols, separated by 72 hours, in a randomized order: a) high intensity training at 80% of 1RM (HIRE) and b) low intensity training at 20% of 1RM combined with blood flow restriction (LIRE + BFR). Three sets of four exercises (bench press, squat, barbell bent-over row and deadlift) were performed. Oxygen consumption and excess post-exercise oxygen consumption were measured. Results: the data showed statistically significant differences between the traditional high intensity training and low intensity training with blood flow restriction, with higher values for traditional training sessions, except for the last five minutes of the excess post-exercise oxygen consumption. Oxygen consumption measured during training was higher (p = 0.001) for the HIRE (20.32 ± 1.46 mL·kg-1·min-1) compared to the LIRE + BFR (15.65 ± 1.14 mL·kg-1·min-1). Conclusion: Oxygen uptakes rates during and after the exercise sessions were higher for the high intensity training methodology. However, when taking into account the volume of training provided by both methods, these differences were attenuated. Level of Evidence III - Non-consecutive studies, or studies without consistently applied reference stand.
... Participaram desse estudo 14 voluntários do sexo masculino, treinados na musculação. Como critério de inclusão para participação, foram considerados treinados os indivíduos que conseguiram realizar uma repetição no exercício supino com o peso equivalente ao de sua massa corporal (KEOGH, WILSON & WEATHERBY, 1999) e que estavam praticando musculação regularmente a seis no exercício de flexão de cotovelos. Alguns estudos reportaram que o treinamento com ADMP é eficaz para aumentar a força muscular em testes de 1 RM realizados com ADMC (MASSEY, VINCENT, MANEVAL, MOORE & JOHNSON, 2004; MASSEY, VINCENT, MANEVAL & JOHNSON, 2005) e em testes de contração voluntária isométrica máxima em amplitudes diversas (GRAVES, POLLOCK, JONES, COLVIN & LEGGETT, 1989;GRAVES, POLLOCK, LEGGETT, CAPENTER, FIX & FULTON, 1992). ...
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There are divergent results about increases in strength using different ranges of motion (ROM). The aim of this study was to compare the maximum number of repetitions (MNR) in bench press with two different ROM. Fourteen subjects performed familiarization and one repetition maximum (1 RM) tests in sessions 1 and 2. MNR in four sets at 50% of 1 RM, one-minute rest with partial (ROMP) and complete ROM (ROMC) were performed in the third and fourth sessions. The ROMP used half of the bar vertical displacement compared to ROMC. Two-way ANOVA with repeated measures was used to compare the experimental conditions, followed by post hoc Scheffe. There was a significant decrease of the MNR among sets, except from third to fourth sets in both ROM. MNR in all sets was higher in ROMP than ROMC. The reduction of ROM allow to perform higher number of repetitions.
... C oaches aim to leverage the positive outcomes of resistance training in the physical preparation of athletic populations. The imposed training stimuli allow for the exploitation of immediate, accumulative, and long-term delayed training effects (8,23). The favorable results from resistance training are robust, demonstrating utility in the enhancement of a multitude of athletic actions including change of direction (30), linear sprinting (1), jumping ability (25), and throwing ability (35). ...
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Wagle, JP, Cunanan, AJ, Carroll, KM, Sams, ML, Wetmore, A, Bingham, GE, Taber, CB, DeWeese, BH, Sato, K, Stuart, CA, and Stone, MH. Accentuated eccentric loading and cluster set configurations in the back squat: a kinetic and kinematic analysis. J Strength Cond Res XX(X): 000-000, 2018-This study examined the kinetic and kinematic differences between accentuated eccentric loading (AEL) and cluster sets in trained male subjects (age = 26.1 ± 4.1 years, height = 183.5 ± 4.3 cm, body mass = 92.5 ± 10.5 kg, and back squat to body mass ratio = 1.8 ± 0.3). Four load condition sessions consisted of traditionally loaded (TL) "straight sets," TL cluster (TLC) sets, AEL cluster (AEC) sets, and AEL "straight sets" where only the first repetition had eccentric overload (AEL1). An interrepetition rest interval of 30 seconds was prescribed for both TLC and AEC. Concentric intensity for all load conditions was 80% 1 repetition maximum (1RM). Accentuated eccentric loading was applied to repetitions using weight releasers with total eccentric load equivalent to 105% of concentric 1RM. Traditionally loaded cluster had statistically greater concentric outputs than TL. Furthermore, statistically greater eccentric and concentric outputs were observed during AEC compared with TL with the exception of peak power. Statistically greater concentric characteristics were observed in TLC compared with AEL1, but statistically greater eccentric outputs were observed in AEL1. In the 2 cluster set conditions, statistically greater concentric rate of force development (RFDCON) (d = 0.470, p < 0.001) and average velocity (vavg) (d = 0.560, p < 0.001) in TLC compared with AEC were observed. However, statistically greater eccentric work (WECC) (d = 2.096, p < 0.001) and eccentric RFD (RFDECC) (d = 0.424, p < 0.001) were observed in AEC compared with TLC. Overall, eccentric overload demonstrated efficacy as a means of increasing eccentric work and RFD, but not as a means of potentiating concentric output. Finally, interrepetition rest seems to have the largest influence on concentric power output and RFD.
... Relatively few studies have investigated muscle activation when performing dynamic upper body resistance training at different loading intensities. Keogh et al. [10] recruited 12 young experienced lifters to perform the bench press using a variety of training methods including conditions with intensities of 55% and 85% 1RM to failure. Results showed that mean concentric EMG activity of the pectoralis major was significantly higher during the heavy load condition by ∼18%, 19%, and 12%, for the first, middle, and last repetition, respectively. ...
... Time under tension in a set (TUTset) has an effect on the level of post-exercise metabolic and endocrine changes (Bird et al., 2005;Wilk et al., 2018). Extended time of constant muscle tension during a slow movement tempo has a beneficial effect on muscle hypertrophy (Bird et al., 2005;Keogh et al., 1999). There are also scientific reports which have shown that the independent change in cadences in particular phases of movement has an impact on postexercise adaptations. ...
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Volume and intensity of exercise are the basic components of training loads, having a direct impact on adaptive patterns. Exercise volume during resistance training has been conventionally evaluated as a total number of repetitions performed in each set, regardless of the time and speed of performing individual exercises. The aim of this study was to evaluate the effect of varied tempos i.e. regular (REG) 2/0/2/0, medium (MED) 5/0/3/0 and slow (SLO) 6/0/4/0 during resistance exercise on training volume, based on the total number of performed repetitions (REPsum1-5) and time under tension (TUTsum1-5). Significant differences in TUT (s) were found in particular sets for each tempo of 2/0/2/0, 5/0/3/0 and 6/0/4/0 (p < 0.001). The ANOVA also revealed substantial differences in the REP for individual sets (p < 0.001). Post-hoc analyses showed that TUT for each set and total TUTsum1-5 were significantly higher in the 5/0/3/0 and 6/0/4/0 tempos compared to 2/0/2/0 (p < 0.001). REP was significantly higher for the 2/0/2/0 tempo compared to 5/0/3/0 and 6/0/4/0 tempo in each set. Total REPsum1-5, TUTsum1-5 between 5/0/3/0 and 6/0/4/0 tempos were not significantly different. The main finding of this study is that the movement tempo in strength training impacts training volume, both in terms of repetitions and total time under tension.
... This shows that repetition duration may be an important variable for consideration, but further research is needed, as this present review only contained six studies. Regarding contraction type, multiple studies have investigated how to utilize dynamic, eccentric, and concentric contractions to maximize power, strength, and hypertrophy (Headley et al., 2011;Keogh, Wilson, & Weatherby, 1999;Roig et al., 2009;Schroder, Hawkins, & Jaque, 2004;Toumi et al., 2001;Westcott et al., 2001). The literature currently suggests that dynamic RE may be superior to eccentric RE (Headley et al., 2011;Westcott et al., 2001), but this is not a conclusive finding, as eccentric training uses less energy and allows exercisers to achieve a higher absolute force (Schroder et al., 2004); this has been shown to lead to a greater increase in strength, muscular damage, hypertrophy, bone mineral content, and hormonal response (Headley et al., 2011;Roig et al., 2009;Schroder et al., 2004). ...
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Research in aerobic exercise has linked the affective responses (pleasure–displeasure) experienced during exercise to future exercise participation. While this is yet to be confirmed in anaerobic activities, it can be inferred that making resistance exercise (RE) more psychologically rewarding is an important consideration. The purpose of this article is to review the acute effects of RE on affect, anxiety, and mood and to draw conclusions on how to maximize feelings of pleasure in an effort to increase rates of participation. This review provides evidence to support lower training volumes performed at low to moderate intensities (50–70% 1RM) with long inter-set rest intervals (90–150 s). Additional recommendations are provided based on physiological and theoretical support, but there is a strong need for more research on the affective experience of RE.
... Resistance training is performed by recreational weightlifters, powerlifters, bodybuilders, and athletes to increase muscular endurance, hypertrophy, strength, and/or power. In conjunction with traditional training protocols, nontraditional resistance protocols can be beneficial to prevent or overcome plateaus, provide alterations within a mesocycle, and prevent mental fatigue during a training program (Keogh et al. 1999;Marshall et al. 2012). Schoenfeld (2013) occur from metabolic stress (i.e., lactate and H + buildup), and mechanical stress (i.e., volume manipulations). ...
Article
Purpose: Rest-pause (4 s unloaded rest between repetitions) single session training effects on lifting volume, and muscle activity via electromyography (EMG) are currently vague in the literature and can benefit strength and conditioning professionals for resistance training program design. This study compared differences in volume lifted and muscle activity between a rest-pause vs. traditional protocol. Methods: Trained females (N = 13) completed both a rest-pause and traditional squat protocol consisting of four sets to movement failure at 80% pretest 1 repetition maximum load with 2-min rest between sets. Total volume and muscle activity of the vastus lateralis, vastus medialis, rectus femoris, and gluteus maximus were measured on both training days. Differences in muscle activity were viewed as a percent change (%∆). Results: A paired samples t test indicated total volume lifted was higher in the rest-pause compared to the traditional protocol (2532 vs. 2036 kg; p < .05). Furthermore, paired samples t tests showed muscle activity %∆ of the gluteus maximus was greater in the traditional protocol compared to the rest-pause protocol (p < .05). No other muscle activity differences were observed in the remaining muscles. Conclusions: The rest-pause allows for greater volume lifted via increased repetitions compared to a traditional protocol in trained women. The rest-pause method may be superior to a traditional method of training during a hypertrophy mesocycle, where a primary focus is total volume lifted. Furthermore, %∆ muscle activity in the GM will be greater while performing a traditional back squat protocol in comparison to a rest-pause.
... O treinamento com pesos tem demonstrado eficácia no desenvolvimento da aptidão neuromuscular, por aprimorar os aspectos de controle da atividade muscular, tolerância à perturbação metabólica e remodelamento tecidual. [1][2][3][4][5][6][7][8][9][10][11] Inicialmente, houve uma tendência em caracterizar a demanda energética em exercícios com pesos e, consequentemente, sua aplicabilidade aos programas de condicionamento físico, propondo perfis de custo calórico, 1 analisando o papel no condicionamento cardiorrespiratório, 2 determinando a demanda sobre o metabolismo anaeróbio, 3,4 relacionando formas de execução do exercício com a intensidade do esforço, 5 e verificando a influência de diferentes prescrições do treinamento resistido sobre respostas hormonais e efeitos ergogênicos. 6 Recentemente, as temáticas abordam o modo de prescrição do treinamento resisitido e seus efeitos sobre a expressão miogênica, 7 desempenho em exercícios de potência e força 8,10,11 e sinalizadores de danos muscular, 9 evidenciando o papel da fisiologia molecular na compreensão das respostas bioquímicas, metabólicas e teciduais das adaptações neuromusculares ao treinamento resistido. ...
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Introdução: O treinamento em circuito é um modelo de treinamento resistido que permite uma variada combinação de sobrecarga e, por isso, requer mais informações para que se compreenda a demanda glicolítica anaeróbia durante sua execução. Objetivo: O objetivo foi comparar dois protocolos de treinamento com pesos, com (Tconv) e sem (Tcirc) pausa entre as execuções, quanto à resposta do lactato sanguíneo ([la]). Métodos: Onze homens (21,0 ± 2,3 anos; 76,7 ± 5,4 kg, 179,5 ± 7,0 cm) foram submetidos ao teste de repetição máxima. O Tcirc e o Tconv foram prescritos a 60%1RM, 12 repetições, sendo três passagens com pausa de 300 s para Tcirc e três séries de cada exercício com 180 s de pausa para o Tconv. Os exercícios que compuseram ambos os protocolos de treinamento foram: supino reto, cadeira extensora unilateral, peck-deck, mesa flexora, pulley alto, leg press 45º, remada horizontal e panturrilha no hack. O teste de ANOVA (Bonferroni post hoc) comparou o [la] no 1º, 3º e 5º minuto após as passagens no Tcirc e após cada série no Tconv. O teste t independente comparou as médias do pico de lactato entre Tcirc e Tconv. Em todas as análises adotou-se p ≤ 0,05. Resultados: Foram observadas diferenças para o [la] entre a 1ª (10,6 ± 1,0 mmol/l) e a 2ª passagem (13,5 ± 1,8 mmol/l, P = 0,01) e entre a 1ª e a 3ª passagem (15,0 ± 2,5 mmol/l, P < 0,01) no Tcirc. Durante Tconv, os maiores valores médios de [la] foram observadas nos exercícios pulley alto (11,2 ± 2,2 mmol/l) e leg press 45º (11,9 ± 2,6 mmol/l). Houve diferença (P < 0,01) ao comparar o pico de [la] após Tconv (12,8 ± 2,2 mmol/l) e Tcirc (15,9 ± 2,0 mmol/l). Conclusão: O Tcirc demanda maior resposta glicolítica, enfatizando sua efetividade no aumento da capacidade anaeróbia muscular. Além disso, a execução não intermitente do Tcirc pode explicar sua maior demanda glicolítica, uma vez que Tconv e Tcirc foram proporcionalmente delineados, quanto ao volume e carga do protocolo. Nível de Evidência I; Estudos diagnósticos-Investigação de um exame para diagnóstico.
... When lifting at intentionally slower movement velocities, the heaviest load that can be performed for a specific number of repetitions (e.g. 8-10 RM) will be lighter compared to faster movement velocities due to reductions in force (Keogh, Wilson, & Weatherby, 1999). This may have implications when the objective of training is to increase muscle mass due to the greater hypertrophic responses that have been associated with heavy loads (Fry, 2004). ...
Article
Currently, it is unclear whether manipulation of movement velocity during resistance exercise has an effect on hypertrophy of specific muscles. The purpose of this systematic review of literature was to investigate the effect of movement velocity during resistance training on muscle hypertrophy. Five electronic databases were searched using terms related to movement velocity and resistance training. Inclusion criteria were randomised and non-randomised comparative studies; published in English; included healthy adults; used dynamic resistance exercise interventions directly comparing fast training to slower movement velocity training; matched in prescribed intensity and volume; duration ≥4 weeks; and measured muscle hypertrophy. A total of six studies were included involving 119 untrained participants. Hypertrophy of the quadriceps was examined in five studies and of the biceps brachii in two studies. Three studies found significantly greater increases in hypertrophy of the quadriceps for moderate-slow compared to fast training. For the remaining studies examining the quadriceps, significant within-group increase in hypertrophy was found for only moderate-slow training in one study and for only fast training in the other study. The two studies that examined hypertrophy of the biceps brachii found greater increases for fast compared to moderate-slow training. Caution is required when interpreting the findings from this review due to the low number of studies, hence insufficient data. Future longitudinal randomised controlled studies in cohorts of healthy adults are required to confirm and extend our findings.
... Optimal prescription of resistance training programs relies on proper organization of training variables such as frequency, intensity, volume, rest intervals, velocity, choice and order of exercise, and periodization 1,2 . Previous research has demonstrated the importance of varying training methods to provide increasing and consistent results [3][4][5] . One of these methods consists of performing an exercise that requires simultaneous actions of contralateral muscles that perform opposite movements, for example, the right elbow flexors and the left elbow extensors 6 . ...
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Aim the aim was to investigate the influence of a maximal isometric muscle action of the elbow extensors on the contralateral dynamic task of the elbow flexors. Methods Seventeen recreationally trained men (23.3 ± 4.9 yrs, BMI: 24.8 ± 2.2 Kg/m²) underwent two randomized different testing sessions separated by one week. In the control session (CON) all subjects performed a maximum number of repetitions test (RMs) at 75%1RM using the right elbow flexors. The experimental session (EXP) was similar to the CON; however, all subjects were instructed to perform RMs at 75%1RM by using the right elbow flexors and maintaining the maximal voluntary contraction of the left elbow extensors during the test. RMs, rating of perceived exertion (RPE), and training volume (TV) were measured and compared between sessions. Results The EXP showed a significant 10.4% increase on the RMs (13.8 vs. 12.5, p < 0.001, d = 0.44) and 12.1% increase in TV (238.0 vs. 212.4 kg, p < 0.001, d = 0.43) than CON. No differences were observed for RPE between sessions. Conclusion The maximum voluntary contraction of the left elbow extensors increased the RMs of the contralateral elbow flexors, reflecting a higher TV, and no differences in the RPE. Our results suggest that the investigated method may be a viable and practical alternative to increase the acute strength performance of elbow flexors when using submaximal loads.
... A resistance training based technique that fits these requirements is the rest-pause technique and its variants (Korak et al., 2017). Rest-pause techniques involve a pause (that may vary in duration) between a certain number of repetitions within a set (Keogh et al., 1999;Korak et al., 2017;Marshall et al., 2012). We previously investigated the effect of a variant of the rest-pause technique, called high-intensity interval resistance training (HIIRT), on metabolism in young adult males . ...
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Introduction: The effects of low intensity resistance training combined with vascular occlusion have been investigated by several studies. Similar results on strength and hypertrophy have been observed when such method was compared to high intensity protocols. However, due to the specific apparatus needed to apply vascular occlusion (ex.: Kaatsu) on some exercises, alternative forms of metabolic training might be used. In the present study, an isometric contraction was performed within each concentric-eccentric transition phase, for every repetition, to elicit metabolic stress. Objective: The aim of the present study was to analyze the effects of two resistance training protocols with metabolic characteristics on strength (1MR), circumference (CIRC) and muscle thickness (measured with ultrasonography [MT]). Subjective perception of discomfort was also recorded with an analogical-visual pain scale (AVP). Methods: Twelve young, healthy men were trained with two different methods during 10 weeks. The right limb was trained with an isometric contraction within each concentric-eccentric transition phases for every repetition (ISO) whereas the left limb was trained with a pneumatic cuff to apply vascular occlusion (OC) on the knee extensor muscles. Both methods were trained at 20% 1MR. Results: It was observed increases on medial tight CIRC, proximal MT, medial MT, distal MT and 1MR, with no difference between both methods. The perception of discomfort was greater for ISO at the end of the third set and lower than reported by OC, at the beginning and end of the training program. Conclusions: Both protocols produced similar gains on strength and hypertrophy. The advantages of training with low loads are important to elderly or rehabilitation training programs. Other studies that compare this method with conventional resistance training are warranted.
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Breakdown (BD) training has been advocated by multiple commercial and academic publications and authors, seemingly as a result of the acute hormonal and muscle activation responses it produces. However, there is a relative dearth of research which has empirically considered this advanced method of resistance training (RT) over a chronic intervention whilst appropriately controlling other RT variables. The present study considered thirty-six male and female participants divided in to three groups; breakdown (BD, n=11), heavy-load breakdown (HLBD, n=14) and traditional (CON, n=11), performing full-body resistance training programmes 2 x / week for 12 weeks. No significant between group differences were identified for change in absolute muscular endurance for chest press, leg press, or pull down exercises, or for body composition changes. Effect sizes for absolute muscular endurance changes were large for all groups and exercises (0.86 - 2.74). The present study supports previous research that the use of advanced training techniques stimulates no greater muscular adaptations when compared to performing more simplified resistance training protocols to momentary muscular failure.
Strength training principles In: Network 95 International Fitness Convention and Trade Show, Gold Coast, Australia, 29 November–3 December 1995
  • E Darden
DARDEN, E. Strength training principles. In: Network 95 International Fitness Convention and Trade Show, Gold Coast, Australia, 29 November–3 December 1995. Gold Coast, Australia: Network for Fitness Professionals ; 1995.
Relationship between force, velocity, power and work during isokinetic, isotonic and 1RM free weight squat and bench press exercise in college age men
  • T Hortobagyi
HORTOBAGYI, T., AND P.E. LACHANCE. Relationship between force, velocity, power and work during isokinetic, isotonic and 1RM free weight squat and bench press exercise in college age men. Hung. Rev. Sports Med. 28:209–226. 1987.
Resistance training for the strength endurance athlete
WILSON, G.J. Resistance training for the strength endurance athlete. Strength Cond. Coach 1(3):3–6. 1993.
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Häkkinen, K., Komi, P.V.. Effect of different combined concenrtic and eccentric muscle work regimens on maximal strength development. Journal of Human Movement Studies, 1981, 7, 33-44. Thirteen competitive junior weightlifters and 27 non-competitive habitually active weight-trainers, plus l0 controls, served as subjects in an investigation designed to develop marxmal muscle strength using different combined concentric and eccentric work regimens. The experimental period lasted for l2 weeks. One weightlífter group (7 subjects) trained concentrically rvith usual weightlifting exercises and the other weightlifter group (6 subjecrs) perfornred a part (about 25 percent) of the same progressive prograrnme eccentrically. The non-competitive weight-trainers were divided into three different training groups-one group (9 subjects) trained concentrically with progressively increasing loads mainly for the leg extcnsors (squat) and the arm exrensors (bench press) Tlte second group (9 subjects) performed the same programme but about 50 percent exercises was done eccentrically, The third group (9 subjects) perfornred atrout 75 percent of the exercises eccentrically. The parameters studied included maxi¡nal isometric. concentric and eccentric leg extension forces and specific dynamic performance tests. The results showed that generaily all the groups that had used combined muscle rvork regimens increased maximal force and performance test results more than the concentric groups. The strength gains rvere moreover significantly different between the groups in the squat (p<0.01) ancl in isometric force (,P<0.05) among the non-competitive subjects and in the clean & jerk (P<0.05) among the conrperitive junior weightlifters. Optimal utilization of combined concentric and eccentric work is suggesrecl to be effective in training for maximal force
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This experiment investigated the effects of varying bench inclination and hand spacing on the EMG activity of five muscles acting at the shoulder joint. Six male weight trainers performed presses under four conditions of trunk inclination and two of hand spacing at 80% of their predetermined max. Preamplified surface EMG electrodes were placed over the five muscles in question. The EMG signals during the 2-sec lift indicated some significant effects of trunk inclination and hand spacing. The sternocostal head of the pectoralis major was more active during the press from a horizontal bench than from a decline bench. Also, the clavicular head of the pectoralis major was no more active during the incline bench press than during the horizontal one, but it was less active during the decline bench press. The clavicular head of the pectoralis major was more active with a narrow hand spacing. Anterior deltoid activity tended to increase as trunk inclination increased. The long head of the triceps brachii was more active during the decline and flat bench presses than the other two conditions, and was also more active with a narrow hand spacing. Latissimus dorsi exhibited low activity in all conditions. (C) 1995 National Strength and Conditioning Association
Article
Typically, investigators have used strength increases to evaluate the effectiveness of various progressive resistance training protocols, which is fine as long as strength gains are the only goal of the training. However, using strength gains as indicators for muscle mass increases can be misleading, since motor learning skills also play a role in muscle strength. The purpose of this investigation was to examine the relationship of various training variables, gathered during each daily training session, to exercise- induced muscle enlargement. Sixty-two cats trained their right palmaris longus muscle (PLM) by performing a wrist flexion movement against resistance. The left PLM served as the non-exercised intra-animal control. All cats began training by lifting 100 grams. They trained five days/week and after an average 90 weeks (range 30 to 311), the left and right PLMs were removed and weighed. The average increase in PLM mass was 10.6 percent +/- 2.2percent (p < 0.001) with the maximum increase being 100 percent. Twenty-six primary training variables and 133 other variables derived from the primary variables were correlated to the resulting muscle enlargement using bi- and multi-variate analysis. The training variable demonstrating the highest correlation to change in muscle mass was the average lift time, which is the time required to complete a successful lift (r = 0.71). As expected, highest percent body weight lifted (r = 0.46) demonstrated a significant correlation to muscle mass increases. Furthermore, cats lifting less tban 30 percent of their body weight did not demonstrate significant mass increases. Cats demonstrating the greatest mass increases performed nine to 26 lifts per day. The average rest time taken between the lifts did not appear to be related to the magnitude of the increase. Multi-variate stepwise linear regression analysis revealed that 82 percent (r = 0.89) of the exercise-induced muscle mass increase could be explained by four training variables, which were the lift time, particularly through the first 10 to 20 millimeters of the lift, the percent weight lifted, the power exerted in unsuccessful lifts, and the rate of progression, which is the rate at which the weight lifted was increased. The results suggest that lifting heavy weights with slow lifting movements and performing nine to 26 lifts per day are best suited for eliciting muscle enlargement in the cat. This is the first time that exercise performance has been directly correlated to increases in muscle mass, and should provide the basis for directly testing the relationship between exercise variables, especially slow lifting speed, in human athletes. (C) 1989 National Strength and Conditioning Association
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This study examined the comparative effects of functional isometric (FI) and heavy weight (HW) training on the development of strength and power together with specific hormonal adaptations in experienced athletes. Thirty three subjects were randomly divided into 3 groups: Fl weight training, HW, and Control. Both the FI and HW completed an 8-week training cycle involving 2 sessions a week. All subjects were tested on the following measures: 1-RM (repetition maximum) bench press; 1-RM squat; 40-m sprint; countermovement jump (CMJ); stretch-shorten cycle (SSC); and concentric push-up. Urinary concentrations of testosterone (T), Cortisol (C), and luteinizing hormone (LH) were assessed via liquid chromatography, and immunoassay techniques and ratios were used to determine the anabolic or catabolic response to the different training methods. Both FI and HW training significantly increased muscular strength. Furthermore, the HW group significantly improved in the CMJ compared to the control group. Among the stronger subjects, Fl resulted in greater improvements in upper body SSC movements compared to the HW training. Urinary concentrations of T, C, LH, as well as the hormone ratios, were unaffected by either training modality. (C) 1998 National Strength and Conditioning Association
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Six men were studied to determine the interrelationships among blood supply, motor unit (MU) activity and lactate concentrations during intermittent isometric contractions of the hand grip muscles. The subjects performed repeated contractions at 20% of maximal voluntary contraction (MVC) for 2 s followed by 2-s rest for 4 min with either unhindered blood circulation or arterial occlusion given between the 1st and 2nd min. The simultaneously recorded intramuscular MU spikes and surface electromyogram (EMG) data indicated that mean MU spike amplitude, firing frequency and the parameters of surface EMG power spectra (mean power frequency and root mean square amplitude) remained constant during the experiment with unhindered circulation, providing no electrophysiological signs of muscle fatigue. Significant increases in mean MU spike amplitude and frequency were, however, evident during the contractions with arterial occlusion. Similar patterns of significant changes in the surface EMG spectra parameters and venous lactate concentration were also observed, while the integrated force-time curves remained constant. These data would suggest that the metabolic state of the active muscles may have played an important role in the regulation of MU recruitment and rate coding patterns during exercise.
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The aim of this study was to investigate the kinematics, kinetics, and neural activation of the traditional bench press movement performed explosively and the explosive bench throw in which the barbell was projected from the hands. Seventeen male subjects completed three trials with a bar weight of 45% of the subject's previously determined lRM. Performance was significantly higher during the throw movement compared to the press for average velocity, peak velocity, average force, average power, and peak power. Average muscle activity during the concentric phase for pectoralis major, anterior deltoid, triceps brachii, and biceps brachii was higher for the throw condition. It was concluded that performing traditional press movements rapidly with light loads does not create ideal loading conditions for the neuromuscular system with regard to explosive strength production, especially in the final stages of the movement, because ballistic weight loading conditions where the resistance was accelerated throughout the movement resulted in a greater velocity of movement, force output, and EMG activity.
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The aim of this study was to investigate the kinematics, kinetics, and neural activation of the traditional bench press movement performed explosively and the explosive bench throw in which the barbell was projected from the hands. Seventeen male subjects completed three trials with a bar weight of 45% of the subject's previously determined 1RM. Performance was significantly higher during the throw movement compared to tile press for average velocity, peak velocity, average force, average power, and peak power. Average muscle activity during the concentric phase for pectoralis major, anterior deltoid, triceps brachii, and biceps brachii was higher for the throw condition. It was concluded that performing traditional press movements rapidly with light lends does not create ideal loading conditions for the neuromuscular system with regard to explosive strength production, especially in the final stages of the movement, because ballistic weight loading conditions where the resistance was accelerated throughout the movement resulted in a greater velocity of movement, force output, and EMG activity.
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The overhead throw in water polo is the most effective and frequently used method of propelling the ball and scoring goals. Related research has usually examined throws performed on land and this information is then adopted for modelling the overhead throw in water polo. However, the benefits derived from this method of performance modelling are doubtful since the throw performed in water differs markedly from the on-land version. This study sought to examine the relationship between muscular strength and morphology of elite water polo players (n = 21) with overhead throwing velocity. An eight week, intervention strength training program comprising exercises using the 'Nautilus' system and emphasising upper body strength development was performed on one group of players. A control group, who did not supplement their regular swimming and game practice with specific strength training, were used for comparison. Significant relationships (p < 0.01) with throwing velocity were found to exist for standing height, body mass, lean body mass, stem length, biacromical width, arm girth and forearm extension strength. Following the strength training intervention program no change in overhead throwing velocity was recorded for either the treatment or control group, although significant increases (p < 0.01) in arm girth, mesomorphy and arm medial rotation strength were demonstrated by the treatment group alone.
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Normalization of electromyographic (EMG) data has been described in the scientific literature as crucial for comparisons between subjects and between muscles. The reference value used in the normalization equation has, however, varied across reports. Comparison between studies could be facilitated by use of a common value. We propose the best way to select the common value is through a reliability approach. Accordingly, the purpose of this study was to identify which of three EMG normalization values provided the most reproducible data set. The gastrocnemius EMG results from 20 normal persons and 20 individuals with anterior cruciate deficiency who were participating in a larger study were normalized to a maximum voluntary isometric contraction (MVIC) EMG, peak dynamic EMG, and mean dynamic EMG. Values were then subjected to evaluation using four statistical measures: inter and intrasubject coefficients of variation (CV), variance ratio (VR), and intraclass correlation coefficient (ICC). The CV measures, while not being reflective of reliability were included for comprehensive consideration in view of other literature. The intersubject CV which measures group variability and the intrasubject CV which measures precision were lower for the dynamic conditions, however, the VR and ICC suggested reproducibility was best with EMG from the MVIC. Given that other studies have advocated normalizing EMG by taking data from the dynamic event, reconsideration may be warranted if high reproducibility is desired. Interpretations of the findings given the population, muscle and condition studied are discussed.
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Nine different weight training programs were compared to determine which were more effective in improving strength. The experiment was conducted with the bench press lift for a period of 12 weeks with approximately 20 subjects in each weight training program. Subjects were tested for the 1 RM on the bench press lift at the beginning of training and at three-week intervals. Training took place three times weekly with the variations in programs involving one, two, and three sets, and two, six, and ten repetitions per set. The results showed that three sets and six repetitions per set were best for improving strength.
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This study calculated IEMG values during the ascent and descent phases of the bench press and compared the values between lifts performed with free weights versus a guided weight machine. In Phase 1 of the study the 1-RM on each mode was determined for each subject. In Phase 2, EMG data were collected from five muscles of the upper extremity while each subject completed five trials at 80% of 1-RM and five trials at 60% of 1-RM for each mode. Linear envelopes were created from the EMG data of each trial, and IEMG values were calculated during the descent and ascent phases of each trial. Planned comparisons were used to compare mean IEMG values between the two loads within the same mode, and between the two modes at both the 60% and 80% loads. Results suggested greater muscle activity during the free-weight bench press, especially at the 60% 1-RM load, although there were notable differences among the patterns of individual subjects.
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This study was supported in part by a grant from the Foundation for Physical Therapy, Inc. The purpose of this study was to compare the relationships among isometric, isotonic, and isokinetic concentric and eccentric quadriceps and hamstring forces and three components of athletic performance in college-aged, male athletes. Bilateral quadriceps and hamstring muscle torque were obtained (N = 39) using a KinCom(R) for concentric (rate at 60 degrees /sec and 180 degrees /sec), eccentric (rate at 30 degrees /sec and 90 degrees /sec), isotonic, and isometric (knee angles at 30 degrees and 60 degrees ) contractions. Athletic performance was assessed using vertical jump performance, 40-yard dash time, and agility run time. The best predictor of 40-yard dash time was the right peak isokinetic concentric hamstring force at 60 degrees /sec (R = .57; p < 0.05). The best predictor of agility run time was the left mean isokinetic eccentric hamstring force at 90 degrees /sec (R = .58; p < 0.05). There were no significant correlations between any quadriceps or hamstring force and vertical jump. It was concluded that isokinetic eccentric quadriceps and hamstring forces were no better predictors of athletic performance than muscle forces assessed in other ways. However, they may be more predictive of some specific components of performance. J Orthop Sports Phys Ther 1991;14(3):114-120.
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Isometric and isokinetic (concentric and eccentric, strength of alpine skiers with different performance levels were measured. Nine national (elite, EG) and 10 collegiate (trained, TG) female alpine skiers (16 to 23 years of age) performed maximal voluntary knee extension and flexion. Peak torque was measured at an angular velocity of 30 deg.s-1. The cross-sectional area (CSA) of thigh muscles (quadriceps and hamstring muscles) was determined by an ultrasonic method. No significant differences in anthropometric variables and CSA were observed between EG and TG. EG had significantly greater (p < 0.01 for extensors and p < 0.05 for flexors) eccentric knee extensor and flexor strength than that of TG whereas no significant differences were noted in isometric and concentric strength. Eccentric strength/CSA ratio was also higher for EG than for TG. It was suggested that knee extension and flexion strength during eccentric muscle action might be related to the performance level of alpine skiers.
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Sixteen experienced male powerlifters served as subjects in a training study designed to examine the effect of flexibility training on: (i) the stiffness of the series elastic components (SEC) of the upper body musculature and (ii) rebound and purely concentric bench press performance. Nine of the subjects participated in two sessions of flexibility training twice per week for 8 wk. Prior to and after the training period the subjects' static flexibility, SEC stiffness, rebound bench press (RBP), and purely concentric bench press (PCBP) performance were recorded. The flexibility training induced a significant reduction in the maximal stiffness of the SEC. Furthermore, the experimental subjects produced significantly more work during the initial concentric portion of the RBP lift, enabling a significantly greater load to be lifted in the post-training testing occasion. The benefits to performance achieved by the experimental group consequent to flexibility training were greater during the RBP lift as compared with the PCBP lift. The control subjects exhibited no change in any variable over the training period. These results implied that the RBP performance enhancement observed consequent to flexibility training was directly caused by a reduction in SEC stiffness, increasing the utilization of elastic strain energy during the RBP lift.
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Twenty men were randomized into three groups that performed maximal isokinetic knee extensions five days a week for 12 weeks; a fourth group was a control group. The training protocol was different for the opposite lower extremity of each subject, such that subjects in group I trained at 36 degrees/sec with 20 or 60 repetitions, group II did 20 repetitions at 36 degrees/sec with one limb and 60 repetitions at 108 degrees/sec contralaterally, and group III trained at 108 degrees/sec with 20 or 60 repetitions. Group IV did no training. Bilateral pretraining and posttraining vastus lateralis muscle biopsies were done, and maximal torque-velocity tests (0 degrees to 234 degrees/sec at 18 degrees/sec steps) were performed every two weeks. The muscle biopsies were examined for muscle-fiber area and enzyme activity. Statistical analysis of the torque-velocity curves showed that subjects who trained at 36 degrees/sec made significant overall gains in torque and significantly greater torque gains than those training at 108 degrees/sec. Torque gains were not made uniformly during the 12 weeks of training; they occurred primarily during the initial 4 to 8 weeks. There were no significant increases in muscle-fiber areas in response to training, but there were increases in glycolytic and mitochondrial enzyme activities. These findings suggest that the critical variable for developing strength (maximal torque), at least within the context of isokinetic training, is the amount of torque developed during training.
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The inability of the exercises presently used during space-flight to maintain muscle strength and mass may reflect the absence of eccentric (ecc) muscle actions. This study examined the importance of ecc actions in performance adaptations to resistance training. Middle-aged males performed 4-5 sets of 6-12 repetitions (rep) per set of the leg press and leg extension exercises 2 d each week for 19 weeks. Group CON/ECC (n = 9) performed each rep with concentric (con) and ecc actions, group CON (n = 8) with only con actions. Group CON/CON (n = 10) performed twice as many sets with only con actions. The resistance per set was selected to induce failure within the prescribed number of rep. Eight subjects did not train and served as controls. The increase in the three rep maximum (3RM) after training, in general, showed a hierarchy such that CON/ECC greater than CON/CON greater than CON. The differences (p less than 0.05) were: leg press 3RM with con and ecc actions, CON/ECC greater than CON/CON greater than CON (26 greater than 15 greater than 8%); leg press 3RM with only con actions, CON/ECC or CON/CON greater than CON (22 or 18 greater than 14%); and leg extension 3RM with con and ecc actions, CON/ECC greater than CON (29 greater than 16%). These differences (p less than 0.05) were still evident after 1 month of de-training. The results indicate that omission of ecc actions from resistance training compromises increases in strength, probably because intensity is not optimal.(ABSTRACT TRUNCATED AT 250 WORDS)
The effect of three different training programmes on the maximal speed of an unloaded movement (a karate punch) was studied. Three movement variables were selected: maximal speed of the hand (Vh,max), maximal speed of the shoulder (Vs,max) and elbow extension speed (theta E) simultaneous with Vh.max. The programmes were: training group 1 (TG 1, n = 8) - karate students, dynamic heavy progressive resistance exercise (incline situp and incline bench press) + punch bag exercise; training group 2 (TG 2, n = 8)-karate students, punch bag training; training group 3 (TG 3, n = 5)-no karate experience, dynamic heavy progressive resistance exercise (as in TG 1). The movement variables were calculated from chrono-cyclo photographic recordings of the punches (100 Hz). The level of significance was set at 5%. Sixteen weeks of training gave the following results: significant increases in dynamic strength in all the training groups (14%-53%). In TG 1 the Vh.max increased significantly from 8.49 m.s-1, SD 1.19 to 9.35 m.s-1, SD 1.29 (10%); Vs.max increased significantly in TG 1 by 32% (2.18 m.s-1, SD 0.56 to 2.87 m.s-1, SD 0.98) and in TG 2 by 14% (2.40 m.s-1, SD 0.61 to 2.74 m.s-1, SD 0.52), and in TG 3 theta E at Vh,max increased significantly from 28.6 rad.s-1, SD 4.3 to 32.2 rad.s-1, SD 4.5 (13%). No significant relationships between the changes in maximal muscle strength and the changes in movement speed were found.(ABSTRACT TRUNCATED AT 250 WORDS)
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The purpose of the study was to evaluate selected parameters describing performance characteristics of a free-weight and isokinetic bench press. A secondary purpose was an attempt to clarify the technique requirements essential for a successful lift. Parameters describing the free-weight condition were generated from cinematographic data (150 fps) for five trials each at 90 and 75% of the subject's maximal performance (1RM). Isokinetic data were obtained from an instrumented Cybex Power Bench Press at two speeds corresponding to the average speeds for the free-weight conditions. Despite differences, accommodation appeared to occur for both methods when the lifts were performed maximally. A "sticking region" was defined as the portion of the free-weight activity when the subjects' force application was less than the weight of the bar. No significant difference (P less than 0.05) was observed between the 90% 1RM (26.02%) and 75% 1RM (26.94%) mean relative time values for these regions. For the Cybex device, the percentage of the activity which was isokinetic was longer for the slower speeds of rotation (0.47 rad X s-1 = 70%) and steadily decreased until the movement was only 50% isokinetic at 1.74 rad X s-1. The observed relationships between applied force-time data along with anatomical considerations suggest an ideal technique for the lift.
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The effects of seven weeks of eccentric or concentric muscle conditioning on muscle tension and. integrated electrical activity (IEMG) were investigated on human subjects by using a special electrical dynamometer as a testing and training apparatus. The eccentric conditioning caused, on the average, a greater improvement in muscle tension than did the concentric conditioning. In early conditioning those in the eccentric group experienced soreness in their exercised muscles. This caused a concomitant drop in maximum strength. After the disappearance of pain symptoms, ability to develop tension increased in a linear fashion. Neither method was able to cause statistically significant changes in the maximum IEMG associated with any type of muscle contraction. The regression lino expressing the relationship between IEMG ( μ.v. per sec.) and isometric tension (in percent of maximal voluntary contraction) was parabolic. In this relationship muscle conditioning failed to cause any significant changes in IEMG per unit of tension. Although the IEMG changes due to conditioning were somewhat different in the two experimental groups, it could not be established that either type of conditioning caused increase in the desynchronized firing of motor units.
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The purpose of this research was to identify kinematic factors that could be relevant to performance and injury risk in the bench press. The methods used included: use of high-speed, 2D cinematographic procedures to record the performances of 36 subjects (19 experts and 17 novices), determination of the kinematic and kinetic differences between the groups, and identification of a rationale describing how those kinematic differences could lead to the kinetic differences. Kinematic factors so identified could influence performance and injury risk. In addition to the fact that experts were able to lift 79% more weight than the novices, the pertinent kinetic differences included the following: 1) the difference in peak force exerted while lowering the bar was only 43%; 2) the difference in peak force exerted while raising the bar was only 45%; and 3) the difference in minimum force exerted while raising the bar was 87%. There was no significant difference in torque required at the shoulder. The relevant kinematic differences were: 1) the expert group maintained a smaller bar speed while lowering the bar, 2) the expert group used a bar path closer to the shoulders; and 3) the expert group used a different sequence of bar movements. The roles of these kinematic factors in the bench press merit further investigation.
Twenty-one male volunteers (ages 23-25 years) were tested pre- and post training for maximal knee extension power at five specific speeds (1.05, 2.09, 3.14, 4.19, and 5.24 rad X s-1) with an isokinetic dynamometer. Subjects were assigned randomly to one of three experimental groups; group S, training at 1.05 rad X s-1 (n = 8), group I, training at 3.14 rad X s-1 (n = 8) or group F, training at 5.24 rad X s-1 (n = 5). Subjects trained the knee extensors by performing 10 maximal voluntary efforts in group S, 30 in group I and 50 in group F six times a week for 8 weeks. Though group S showed significant increases in power at all test speeds, the percent increment decreased with test speed from 24.8% at 1.05 rad X s-1 to 8.6% at 5.24 rad X s-1. Group I showed almost similar increment in power (18.5-22.4 at all test speeds except at 2.09 rad X s-1 (15.4%). On the other hand, group F enhanced power only at faster test speeds (23.9% at 4.19 rad X s-1 and 22.8% at 5.24 rad X s-1).
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The effects of three resistance training programs on muscular strength and on absolute and relative muscular endurance were investigated. Forty-three male college students were randomly assigned to the training protocols. The high resistance-low repetition group (n = 15) performed three sets of 6–8 RM (repetition maximum) per session. The medium resistance-medium repetition subjects (n = 16) trained by doing two sets of 30–40 RM per session, while the low resistance-high repetition group (n = 12) used a single set of 100–150 RM. All subjects trained with the bench press exercise three times per week for nine weeks. Tests of strength (1-RM), absolute and relative endurance were administered before and after training. Statistical analyses revealed that the 20% improvement in maximum strength by the high resistance-low repetition group was greater than the 8 and 5% gains reported for the medium resistance-medium repetition and low resistance-high repetition groups, respectively. Relative to absolute endurance, however, the 41 percent and 39 percent improvements registered by the low resistance-high repetition and medium resistance-medium repetition groups, respectively, were not significantly greater than the 28% gain reported for the high resistance-low repetition group. Results for the relative endurance test revealed that the high resistance-low repetition group's performance actually decreased by 7% after training, and was significantly poorer than the 22% and 28% improvements made by the other two groups. It was concluded that human skeletal muscle makes both general and specific adaptations to a training stimulus, and that the balance of these adaptations is to some extent dependent upon the intensity and duration of the training protocol used.
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The separate effects of negative (eccentric) and positive (concentric) work on stimulated and voluntary isometric contraction of the triceps surae were studied in five healthy male subjects following the performance of boxstepping for 1 h with a constant leg lead. The results showed unequivocally that the long-lasting muscle weakness which arises from box-stepping was due to the negative component of the work. The maximal twitch (\(P_{ t_{_0 } } \)) and tetanic (P 0) tensions at 10, 20, 50 and 100 Hz were markedly reduced in the leading (“negative”) leg, which was constantly required to absorb the force of body weight as the subject returned from box to floor, whereas the trailing (“positive”) leg which lifted body weight from floor to box was relatively unaffected. The decreases in\(P_{ t_{_0 } } \) andP 0 at 20 Hz in the “negative” leg following work were 38 N and 765 N (25% and 55%) respectively and recovery was slow (>20 h). A 2 min “fatigue” test reflected the changes inP 0; a reduction of absolute force was only seen in the negative leg though the relative (%) decline in tension was the same in both legs and its rate did not differ significantly following exercise from control conditions, which suggests the muscles were weaker but not more fatiguable following exercise. At submaximal voltages of stimulation muscle tensions at 20 and 50 Hz were enhanced in the “positive” leg but depressed in the “negative” leg, the relative (but not absolute) loss of force being greater at 20 Hz than 50 Hz which gave rise to long-lasting fall in the 20/50 tension ratio. The loss of high frequency (50 Hz) force was associated with changes in MVC: MVC (N)=507+0.937P 0 (N);r=+0.846. It was suggested that repeated stretching of the triceps surae muscles during the eccentric phase of work in the “negative” leg could affect the efficacy of the contractile machinery directly and may cause actual muscle damage. The subjects complained of muscle soreness for 5–7 days after the experiments.
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The development of active isokinetic dynamometers has allowed the assessment of muscular moment under eccentric activations that have different characteristics to concentric actions. It is well documented that at a given angular velocity the eccentric moment is greater than the corresponding concentric moment. The moment-velocity relationship under eccentric conditions has been investigated, with conflicting results. Particularly, eccentric moment was reported to remain similar to, or to increase or decrease with, increasing angular velocity. As with concentric actions, the reliability of isokinetic eccentric measurements is influenced by a number of factors such as gravity, preload force and testing position. Isokinetic dynamometers provide some unique characteristics for rehabilitation applications. Examination of the clinical application of eccentric exercise is limited. Consequently, the use of this exercise modality in prevention and assessment of musculoskeletal injuries should be investigated further.
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To investigate the role of fatigue in strength training, strength increases produced by a training protocol in which subjects rested between contractions were compared with those produced when subjects did not rest. Forty-two healthy subjects were randomly allocated to either a no-rest group, a rest group, or a control group. Subjects in the two training groups trained their elbow flexor muscles by lifting a 6RM weight 6-10 times on 3 d each week for 6 wk. Subjects in the no-rest group performed repeated lifts without resting, whereas subjects in the rest group rested for 30 s between lifts. Both training groups performed the same number of lifts at the same relative intensity. The control group did not train. Subjects who trained without rests experienced significantly greater mean increases in dynamic strength (56.3% +/- 6.8% (SD)) than subjects who trained with rests (41.2% +/- 6.6%), and both training groups experienced significantly greater mean increases in dynamic strength than the control group (19.7% +/- 6.6%). It was concluded that greater short-term strength increases are achieved when subjects are required to lift training weights without resting. These findings suggest that processes associated with fatigue contribute to the strength training stimulus.
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This study was performed to determine which of three theoretically optimal resistance training modalities resulted in the greatest enhancement in the performance of a series of dynamic athletic activities. The three training modalities included 1) traditional weight training, 2) plyometric training, and 3) explosive weight training at the load that maximized mechanical power output. Sixty-four previously trained subjects were randomly allocated to four groups that included the above three training modalities and a control group. The experimental groups trained for 10 wk performing either heavy squat lifts, depth jumps, or weighted squat jumps. All subjects were tested prior to training, after 5 wk of training and at the completion of the training period. The test items included 1) 30-m sprint, 2) vertical jumps performed with and without a countermovement, 3) maximal cycle test, 4) isokinetic leg extension test, and 5) a maximal isometric test. The experimental group which trained with the load that maximized mechanical power achieved the best overall results in enhancing dynamic athletic performance recording statistically significant (P < 0.05) improvements on most test items and producing statistically superior results to the two other training modalities on the jumping and isokinetic tests.
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The role of intramuscular metabolite changes in the adaptations following isometric strength training was examined by comparing the effect of short, intermittent contractions (IC) and longer, continuous (CC) contractions. In a parallel study, the changes in phosphate metabolites and pH were examined during the two protocols using whole-body nuclear magnetic resonance spectroscopy (NMRS). Seven subjects trained three time per week for 14 weeks. The right leg was trained using four sets of ten contractions, each lasting 3 s with a 2-s rest period between each contraction and 2 min between each set. The left leg was trained using four 30-s contractions with a 1-min rest period between each. Both protocols involved isometric contractions at 70% of a maximum voluntary isometric contraction (MVC). The MVC, length:tension and force:velocity relationships and cross-sectional area (CSA) of each leg were measured before and after training. The increase in isometric strength was significantly greater (P = 0.041) for the CC leg (median 54.7%; P = 0.022) than for IC (31.5%; P = 0.022). There were no significant differences between the two protocols for changes in the length:tension or force:velocity relationships. There were significant increases in muscle CSA for the CC leg only. NMRS demonstrated that the changes in phosphate metabolites and pH were greater for the CC protocol. These findings suggest that factors related to the greater metabolite changes during CC training results in greater increases in isometric strength and muscle CSA.
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Isometric assessment of muscular function is a popular form of testing which has been used in exercise science for over 40 years. It typically involves a maximal voluntary contraction performed at a specified joint angle against an unyielding resistance which is in series with a strain gauge, cable tensiometer, force platform or similar device whose transducer measures the applied force. Often both the maximum force and the rate of force development are recorded. These tests have generally shown high reliability in both single and multi-joint test protocols, although the maximum force is typically more reliable than rate of force development. This review outlines the reliability of isometric assessment and discusses a number of methodological considerations designed to enhance reliability and validity, including standardisation procedures, type of instructions, muscular pre-tension, testing position and joint angle. Currently, there appears to be considerable controversy as to the external validity of isometric assessment, particularly the ability of the tests to monitor changes in dynamic performance and their relationship to such performances. Indeed, a number of studies have recently shown that dynamic assessment modalities (isokinetic and isoinertial) are superior in terms of their relationship to dynamic performance and ability to discriminate between athletes of various performance levels compared with isometric assessment. This article reviews the use of isometric assessment in exercise science and consequently outlines a number of neural, mechanical and methodological factors which may have contributed to the contrasting research, and which may limit the ability of isometric assessment to relate to dynamic movement. Because of the large neural and mechanical differences between isometric and dynamic muscular actions, athletic assessment, which is dynamic in its nature, is generally most appropriately accomplished using dynamic muscular assessment methods, and in most instances isometric testing should be avoided.
This study was performed to determine the reliability and validity of a new isokinetic squat device in comparison to knee-extension tests performed using a Cybex. Athletic male subjects (n = 29) performed a series of isokinetic squat tests at 0.4 m.s-1, knee-extension tests at 1.05, 2.09 and 3.14 rad.s-1, and a 6-s stationary cycle test which was used as the measure of functional performance. The squat tests included a purely concentric squat without pre-load, a test with pre-load and a stretch-shorten cycle test. Two trials of each test were performed on one testing occasion. Intraclass correlation co-efficients (r = 0.89-0.96) and co-efficients of variation (3.1-8.7%) were determined between trials, and these indicated that all of the tests were highly reliable. The velocity characteristics of the newly developed system demonstrated that it was an effective isokinetic device, with the mean velocity of 0.41 m.s-1 varying within narrow limits, a relatively small velocity overshoot and an isokinetic portion of movement of approximately 80%. The squat tests demonstrated a higher relationship to cycling performance (r = 0.57-0.65) as compared to the knee-extension tests (r = 0.45-0.51). This difference was amplified when a more homogeneous group of subjects was examined. Further, the squat tests were superior to the knee-extension tests in discriminating between differing levels of cycling performance ability. These differences were believed to be due to the greater specificity of the squat movement, in comparison to the knee extension, to the performance of interest.