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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... Es importante diferenciar los ejercicios que se están utilizando principalmente para el desarrollo de la fuerza (o hipertrofia, dependiendo de las series, repeticiones y pausas utilizadas) o de la potencia. Lo que diferencia esta clasificación de ejercicios de fuerza y ejercicios de potencia es si la realización del ejercicio requiere la aceleración a través del rango de movimiento, lo que resulta en una mayor velocidad de movimiento y por lo tanto en una mayor producción de potencia (Keogh et al., 1999;Wilson et al., 1993). ...
... La utilización del entrenamiento isométrico (FI) funcional. Un ejercicio FI puede realizarse en la primera mitad de un movimiento en la máquina Smith, alterando considerablemente las características de fuerza (Keogh et al., 1999). Otros métodos para la alteración del perfil cinético de los ejercicios incluyen las repeticiones parciales hacia el final de la primera mitad o en la zona de fuerza máxima del levantamiento (Moorkerjee & Ratamess, 1999). ...
... Para incrementar la producción de fuerza y velocidad y reducir la fatiga durante una serie, las repeticiones en forma de bloques (clusters) (Newton & Baker, 2008) o los métodos de "descanso-pausa" o de "división" (Keogh, 1999) pausas entre las repeticiones. Esta reducción de la carga aliviará los efectos de la fatiga acumulada, resultando en un menor grado de deterioro de la producción de fatiga a través de la serie, así como también en el incremento de la fuerza en las repeticiones iniciales en comparación con la forma tradicional de levantar cargas altas (Hanh, 1988). ...
... The bench press (BP) is one of the most popular resistance training exercises (1,3,4,6,9,11). This lift is commonly used by both recreational and competitive athletes to increase upper-body strength under different protocols and loading conditions (9,17). ...
... The bench press (BP) is one of the most popular resistance training exercises (1,3,4,6,9,11). This lift is commonly used by both recreational and competitive athletes to increase upper-body strength under different protocols and loading conditions (9,17). Several studies using the BP as a single exercise or as part of mixed-methods training programs have confirmed its effectiveness to improve neuromuscular qualities, which seems to be conditioned by the execution mode or training technique (e.g., super-slow, eccentric, isometric, free-weight, or Smith machine BP, etc.) (9,11,17). ...
... This lift is commonly used by both recreational and competitive athletes to increase upper-body strength under different protocols and loading conditions (9,17). Several studies using the BP as a single exercise or as part of mixed-methods training programs have confirmed its effectiveness to improve neuromuscular qualities, which seems to be conditioned by the execution mode or training technique (e.g., super-slow, eccentric, isometric, free-weight, or Smith machine BP, etc.) (9,11,17). Among all these variations, the BP throw ([BPT]; i.e., the ballistic version of the BP) is one of the most frequently examined and used types of BP, especially for the development of power-related capacities (4,5,17). ...
Article
The purpose of this study was to determine the relative load (% of one-repetition maximum [1RM]) at which the concentric action becomes entirely propulsive in the bench-press (BP) exercise and verify whether this relative load varies between athletes with different strength levels. Twenty-eight professional athletes (Olympic boxers, professional mixed martial arts fighters, and elite rugby players) performed a progressive loading test up to their 1RM in the BP exercise (BP-1RM). Athletes were ordered according to their relative strength values and equally divided into two different groups: “low” (≤1.34) and “high” (≥1.38) strength levels. An independent t-test was used to compare the variables between groups. Significance level was set at P< 0.05. No significant differences were observed between the groups for the mean propulsive velocity attained at 1RM and for the maximum load that required braking action during the execution of the traditional BP exercise (ES = 0.27 and 0.15, respectively; P> 0.05). Our results revealed that at 80% 1RM the concentric action can already be considered as 100% propulsive in the BP exercise. Importantly, this occurrence was independent of strength level. Therefore, this relative strength measure (i.e., 80% BP-1RM) may be used as a reference for the 1RM in the BP throw.
... 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) 1 3 occur from metabolic stress (i.e., lactate and H + buildup), and mechanical stress (i.e., volume manipulations). ...
... Furthermore, mechanical and metabolic stress occur in tandem making it difficult to distinguish their effects independently (Schoenfeld 2013). Rest-pause, defined as a brief inter-repetition unloaded rest period, is one example of a nontraditional resistance training protocol (Keogh et al. 1999). The restpause technique may lead to increases in muscle hypertrophy by permitting the completion of a greater total work volume during a training session (Hedrick 1995). ...
... The rest-pause method, in theory, should allow for greater creatine phosphate replenishment, allowing the ATP-PCr system to sustain muscular efforts for a longer duration. Keogh et al. (1999) defined rest-pause as a 2-s unloaded rest period after each concentric repetition, and found participants averaged 1.3 more repetitions on the Smith machine bench press in comparison to a traditional protocol with a six repetition maximum (RM) load. The restpause group had lower muscle activity of the pectoralis major and triceps muscles in comparison to traditional training. ...
Article
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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.
... Strength and conditioning professionals, athletes, and recreational body builders aim to maximize hypertrophy and strength gains by altering lifting volume and rest periods during training. Several training strategies, including heavy 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. ...
... The prescribed rest period between repetitions has varied among different studies. Keogh et al. (1999) utilized a two second rest period between each repetition for the rest-pause lifting protocol, while Marshall et al. (2012) set the rest period at 20 s after completing a 20-repetition maximum (RM) for the squat exercise. ...
... The adenosine triphosphate-phosphocreatine (ATP-PCr) system can sustain muscle energy requirements for approximately 10 s during high-intensity exercise bouts (McArdle et al. 2014). Inter-set rest periods allow for replenishment of intramuscular creatine phosphate (Keogh et al. 1999;Lawton et al. 2006). Rest periods have extensively been examined and Miranda et al. (2007) concluded that rest periods of 3 min appear to have much more significant increase in volume lifted in comparison to 1-min rest periods. ...
Article
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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.
... 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. ...
... 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. The normalized EMG amplitude was similar for PM and TB [9,10,21] and higher for PM than for AD [11,13,22]. Moreover, TB can be considered the most sensitive in activity change because TB activity was greater than or less than both the PM and AD in different studies, which indicated that there is no consistent pattern and that other factors play a role. ...
... Moreover, TB can be considered the most sensitive in activity change because TB activity was greater than or less than both the PM and AD in different studies, which indicated that there is no consistent pattern and that other factors play a role. TB activity was lower than PM [11,22] under isometric conditions [10], lower in the 80% of 1RM condition compared to AD [22] and higher than PM and AD [13] during bar vibration. Based on data that indicate that TB is similar to PM and that PM activity is greater than AD, it can be concluded that PM and TB show greater activity than AD. ...
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.
... repetition at 80%1RM. In fact, multiple studies have shown that performing exercises using a slower tempo consisting of 5-or 6-s eccentric and concentric phases results in a significantly longer total TUT compared to a faster movement tempo [10,14,30,46], but these studies did not consider the load, volume, and TUT all together. Since heavier loads result in greater motor unit recruitment and tension is one of the major stimulants of muscular hypertrophy and changes in muscle architecture [28], if the TUT is extended, greater hypertrophy adaptations could be achieved [22,30]. ...
... Furthermore, consideration should be given to determining not only the TUT for the entire movement but also independently for particular phases of the movement: TUT concentric (TUT-C) and TUT eccentric (TUT-E). Specifically, a slower eccentric movement increases the TUT-E, the level of metabolic stress, the hormonal responses [14,46], and muscle fiber damage and protein degradation [49][50][51], inducing a stronger anabolic signal with the muscle and connective tissue. In contrast to a slower eccentric contraction, it seems beneficial to use faster concentric contractions for muscle hypertrophy by increasing muscle activation [52] and the rate of fatigue [53], which is more effective for stimulating the highest threshold motor units associated with type II fibers [43]. ...
Article
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Hypertrophy and strength are two common long-term goals of resistance training that are mediated by the manipulation of numerous variables. One training variable that is often neglected but is essential to consider for achieving strength and hypertrophy gains is the movement tempo of particular repetitions. Although research has extensively investigated the effects of different intensities, volumes, and rest intervals on muscle growth, many of the present hypertrophy guidelines do not account for different movement tempos, likely only applying to volitional movement tempos. Changing the movement tempo during the eccentric and concentric phases can influence acute exercise variables, which form the basis for chronic adaptive changes to resistance training. To further elaborate on the already unclear anecdotal evidence of different movement tempos on muscle hypertrophy and strength development, one must acknowledge that the related scientific research does not provide equivocal evidence. Furthermore, there has been no assessment of the impact of duration of particular movement phases (eccentric vs. concentric) on chronic adaptations, making it difficult to draw definitive conclusions in terms of resistance-training recommendations. Therefore, the purpose of this review is to explain how variations in movement tempo can affect chronic adaptive changes. This article provides an overview of the available scientific data describing the impact of movement tempo on hypertrophy and strength development with a thorough analysis of changes in duration of particular phases of movement. Additionally, the review provides movement tempo-specific recommendations as well real training solutions for strength and conditioning coaches and athletes, depending on their goals.
... For instance, RP-NF condition adopted a 10.2-s rest period between each repetition which may allow the replenishment of intramuscular creatine phosphate, removal of glycolysis byproducts (i.e. lactate and H +1 ), and lower muscle activity [34,35]. This rest period between repetitions may delay fatigue and reduce neuromuscular stress, allowing the participants to perform greater volume during RP-NF session [13]. ...
... This rest period between repetitions may delay fatigue and reduce neuromuscular stress, allowing the participants to perform greater volume during RP-NF session [13]. In previous studies, when a rest period is adopted between each repetition, it was found a lower muscle activity of pectoralis major and triceps muscles [34] and greater power output (∆ = 21.6 to 25.1%) during the training session [36] when compared to the TRD system (i.e., continuous 6RM in bench press exercise). Thus, employing rest periods between each repetition induces lower neuromuscular fatigue and metabolic demand during the RE session, and consequently may allow participants to perform greater volume in a resistance training session. ...
Article
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BACKGROUND: Traditional and rest-pause systems are commonly used during resistance training. These systems have different rest times between repetitions that might affect neuromuscular status and fatigue level. OBJECTIVE: This study compared the acute effects of traditional and rest-pause resistance exercise done to muscular failure on countermovement jump (CMJ) performance. METHODS: Twenty-nine recreationally strength-trained adults of both sexes aged from 18 to 33 years old performed four experimental resistance exercise sessions (half back-squat exercise) in a randomized order. The experimental conditions were: Traditional system to muscular failure (TR-F; 4 x 15[15RM]) or non-failure (TR-NF; 5 x 12 [15RM]), and rest-pause system to muscular failure (RP-F; 60 reps with 30 s rest between each failure) or non-failure (RP-NF; 60 reps with 10.2 s rest between each repetition). CMJ height was measured at pre-experiment, Post-15 s, and Post-30 min. Perceived recovery was assessed at pre-experiment, lactate concentration Post-2 min, and rating of perceived exertion Post-30 min. RESULTS: CMJ height decrease occurred at Post-15 s and 30 min for the TR-F, TR-NF, and RP-F sessions (p < 0.05). Interaction effects (p < 0.05) showed exercise to muscle failure (TR-F and RP-F) induced greater neuromuscular decrement at Post-15 s, with RP-F leading to a higher CMJ performance impairment at Post-30 min (p < 0.001). Higher blood lactate concentrations were found following TR-F, TR-NF, and RP-F (p < 0.05) than RP-NF conditions, whereas greater internal training load perception was reported after training to muscular failure (p < 0.05) than non-failure exercise. CONCLUSION: Resistance exercise to muscular failure induced greater CMJ height decrement and internal training load perception than non-failure exercise, with RP-F leading to a higher acute neuromuscular performance impairment.
... 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). ...
... 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.
... 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). ...
... The concentric prescription of 100% 1RM used by Ojasto and Häkkinen may have also contributed to the observed fatiguing effect, whereas Munger et al. used 90% 1RM in the front squat (29,31). It has also been suggested that maximal eccentric contractions could have detrimental effects on concentric outputs when coupled, albeit using isokinetic exercise (23). Nonetheless, previous work combined with the findings of the current investigation emphasizes the potentially delicate nature of balancing potentiation and fatigue when using AEL as well as the myriad of programming aspects that should be considered (29,31). ...
Article
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.
... 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). ...
... Also, reductions in load of a significant amount (e.g. reducing load from 85% to 55% 1RM), so that intentionally slower movement velocities can be achieved, will ultimately decrease muscle activation and generation of force (Keogh et al., 1999), thus creating a less optimal environment for muscular hypertrophy. There is also evidence to suggest that slower lifting speeds are less effective for stimulating the highest threshold motor units (Schuenke et al., 2012), which is important since type II muscle fibres have a greater relative growth than type I fibers (Campos et al., 2002). ...
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 . ...
... The mechanical tension is the primary characteristic which leads to strength gains, whereas, the metabolic stress contributes to increasing the muscular endurance. The increase of mechanical tension by the greater number of repetitions with heavy weights (as noted in the present study) is a characteristic that may lead to higher gains in muscle mass 3 . Similarly, the metabolic stress plays an important role in hypertrophy 20 . ...
Article
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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.
... 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. ...
... In this regard, another study compared submaximal protocols differing in the length of a set prescribed through the percentage of 1repetition maximum (1RM), but did so without bearing in mind the total repetitions possible in a set (18). This could have obscured the physiological nature of the perceived responses observed (7,8,16) due to the large inter-subject variability observed when prescribing through the percentage of the 1RM (33). To solve this particular point, a design equating all the loading parameters, specifically the total volume performed between subjects is essential to clarify the effect of set configuration on perceived exertion. ...
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.
... Resistance training (RT) is an exercise that has grown in popularity in recent decades and has been shown to be effective in improving athletic performance, preventing injuries, and playing a major role in muscle conditioning and body weight programs [1][2][3]. Although the sport-and health-related effects of RT are well-documented [4,5], 25-30% of individuals who practice RT are at risk of injury [6,7]; the factors that increase injury prevalence include unsupervised training, uncontrolled management of load intensity, and inappropriate techniques [8]. ...
Article
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Incorrect limb position while lifting heavy weights might compromise athlete success during weightlifting performance, similar to the way that it increases the risk of muscle injuries during resistance exercises, regardless of the individual’s level of experience. However, practitioners might not have the necessary background knowledge for self-supervision of limb position and adjustment of the lifting position when improper movement occurs. Therefore, the computerized analysis of movement patterns might assist people in detecting changes in limb position during exercises with different loads or enhance the analysis of an observer with expertise in weightlifting exercises. In this study, hidden Markov models (HMMs) were employed to automate the detection of joint position and barbell trajectory during back squat exercises. Ten volunteers performed three lift movements each with a 0, 50, and 75% load based on body weight. A smartphone was used to record the movements in the sagittal plane, providing information for the analysis of variance and identifying significant position changes by video analysis (p < 0.05). Data from individuals performing the same movements with no added weight load were used to train the HMMs to identify changes in the pattern. A comparison of HMMs and human experts revealed between 40% and 90% agreement, indicating the reliability of HMMs for identifying changes in the control of movements with added weight load. In addition, the results highlighted that HMMs can detect changes imperceptible to the human visual analysis.
... Resistance training is very important in sports performance, injury prevention and rehabilitation (Alcaraz-Ibañez & Rodríguez-Pérez, 2018;Bourne et al., 2018;Buckthorpe & Roi, 2017;Ferri Caruana et al., 2020). Previous research has shown that several uncontrollable factors (i.e., muscle size and length, joint angle, myotatic reflex and muscle elasticity (Cronin et al., 2008;Kuriki et al., 2012;Watanabe & Akima, 2011)) and controllable factors (i.e., exercise intensity (Keogh et al., 1999), the velocity of movement (Sakamoto & Sinclair, 2012), fatigue (Sakamoto & Sinclair, 2012), mental focus (Snyder & Fry, 2012), movement phases (van den Tillaar et al., 2012) and stability conditions) may affect the degree of muscle activation in dynamic contractions. Therefore, in order to control exercise performance, it is important to understand the impact of each of these controllable factors on muscle activation since they are the key improving training efficiency (Stastny et al., 2017). ...
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Previous research has shown that the velocity of movement can influence muscle activation. However, no studies have investigated the impact of movement velocity under the same load conditions on electromyography (EMG) activity in knee and hip extensors. This study aims to compare the mean muscle activation of gluteus maximus [GM], biceps femoris [BF], semitendinosus [ST] and rectus femoris [RF] in three hip extension exercises (i.e., squat [SQ], hip thrust [HT] and Bulgarian squat [BS]) with two different movement velocities (i.e., maximum velocity [MV] and controlled velocity [CV]). Fifteen physically active students participated. The mean EMG activity of all targeted muscles was measured. Maximum Voluntary Isometric Contraction was used to normalize EMG muscle activation. All muscles were activated to a greater extent in BS at MV than in the same exercise performed at CV. However, during the SQ exercise, EMG differences between velocities were only obtained for BF and GM, and in HT, only for GM (p < .05). In conclusion, higher velocity involves higher activation of the lower-limb muscles, depending on the physical test, and this can be used to better plan the functional recovery of injury, taking it into consideration for intensity progression and avoiding the risks of overly strenuous exercises.
... There are many variables that make up a strength training program, including the choice of exercises, and these depend on the objectives to be reached, as the training results in different physiological and biomechanical stimuli [18,19]. Whether for health or performance oriented purposes, and among the many types of exercises that can be performed within a strength training program, the press bench exercise is one of the most common and traditional [20][21][22][23]. ...
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Featured Application: Bodybuilding training professionals and users who use bench press (BP) should be aware of the implication in choosing another exercise, either to improve muscle activation or to maintain activation levels while seeking another parallel objective. Depending on the grip, we emphasize that a wide grip will have a greater involvement of the pectoralis major in both portions, but should not exceed a width of 200% biacromial distance (BAD) due to increased risk of injury. Otherwise, in the decline of the bench angle, the decrease in the clavicular portion should be considered, as opposed to an increase in the sternal portion. On the contrary, in the inclination there is a decrease in the sternal portion without having a difference in the clavicular compared to the horizontal portion. In addition, the increase in instability in the BP causes a decrease in the intensity of the load that can be moved, reducing the electromyography activity (EMG) of the pectoralis major, although it can be observed that some of these exercises have an application with different objectives due to the fact that they have a greater influence on other muscle groups with a stabilizing function. Focusing on other types of exercises, BP is the one that most involves the pectoralis major. However, other exercises such as push-ups are more accessible and obtain a similar activation when exposed to the same relative load, although it is difficult to increase the load during the exercise. Therefore, the results of our meta-analysis reflect the appropriateness of the BP for safety and efficiency. Abstract: The popularity of the bench press (BP) is justified by being one of the most effective exercises to improve strength and power in the upper body. The primary aim of this systematic review and meta-analysis was to compare the electromyography activity (EMG) of pectoralis muscle between BP and other variants of pectoral exercises (OP). Methods: This study was conducted according to the PRISMA. Original research articles published by March 2023, were located using an electronic search of four databases and yielded 951 original publications. This review included studies that compared the EMG activity of pectoralis muscle between BP and OP. Data were extracted and independently coded by three researchers. Finally, 23 studies were included for systematic review and meta-analysis. Meta-analysis with fixed or random effect model was performed to infer the pooled estimated standardized mean difference, depending on the heterogeneity. The studies were grouped according to the type of the comparison: grip widths, type of grip, inclination of the bench, stability, or exercise type. Results: The original option of BP activates the sternal portion significantly more than the variant with the inclined bench (SMD = 1.80; 95%CI 0.40 to 3.19; p = 0.017). Performing the exercise in an unstable situation produced significantly more activation during the concentric phase than performing the exercise in a stable situation (SMD = −0.18; 95%CI −0.33 to 3.74; p = 0.029). When comparing by type of exercise, greater activations are also seen in the original bench press vs. the comparisons (p = 0.023 to 0.001). Conclusions: The results suggest that the traditional bench press Citation: López-Vivancos, A.; González-Gálvez, N.; Orquín-Castrillón, F.J.; Vale, R.G.d.S.; Marcos-Pardo, P.J. Electromyographic
... However, it was also observed that training at volitionally very slow durations (10 s per repetition) is inferior from a hypertrophy standpoint. The authors speculate on the existence of a possible threshold velocity below which the hypertrophy response is impaired, since it could not be a suitable stimulus to recruit all motor units of a muscle-mainly high-threshold motor units (Keogh et al., 1999). Nevertheless, the training programs analyzed in this study were performed until concentric failure, which implies a progressive increase in fatigue along the set, reducing the motor unit recruitment thresholds, thereby enhancing muscle recruitment (Mitchell et al., 2012). ...
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This umbrella review aimed to analyze the different variables of resistance training and their effect on hypertrophy, and to provide practical recommendations for the prescription of resistance training programs to maximize hypertrophy responses. A systematic research was conducted through of PubMed/MEDLINE, SPORTDiscus and Web of Science following the preferred reporting items for systematic reviews and meta-analyses statement guidelines. A total of 52 meta-analyses were found, of which 14 met the inclusion criteria. These studies were published between 2009 and 2020 and comprised 178 primary studies corresponding to 4784 participants. Following a methodological quality analysis, nine meta-analyses were categorized as high quality, presenting values of 81-88%. The remaining meta-analyses were rated as moderate quality, with values between 63-75%. Based on this umbrella review, we can state that at least 10 sets per week per muscle group is optimal, that eccentric contractions seem important, very slow repetitions (≥10s) should be avoided, and that blood flow restriction might be beneficial for some individuals. In addition, other variables as, exercise order, time of the day and type of periodization appear not to directly influence the magnitude of muscle mass gains. These findings provide valuable information for the design and configuration of the resistance training program with the aim of optimizing muscle hypertrophy.
... Strength testing and experimental sessions were separated by at least 72 hours. Since bench press exercises have been commonly used among various trained individuals and the load can be easily controlled to ensure safety (19), a bench press exercise was selected as a highintensity resistance exercise session in this study. In addition, we rst examined the effect of intensity aimed at muscle hypertrophy (75% of 1 RM), which was observed to increase greater acute cortisol levels in previous studies (20,21). ...
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Background The cortisol awakening response (CAR) reflects the physical adaptation to exercise and training loads and has been reported the response especially by high-intensity exercise. However, few studies have examined the effects of resistance exercise. The purpose of this study was to investigate the effect of high-intensity resistance exercise on the CAR. Methods Thirteen healthy male university students performed 1 repetition maximum (1 RM) tests and an experimental session for 4 consecutive days: sedentary control sessions (Day 1 and 2), high-intensity resistance exercise (bench press) session at 75% of 1 RM (HIRE; Day 3), and recovery session (Day 4). Saliva samples for Day 1–3 were collected: 1) before and 2) immediately after the session, 3) 10 min, 4) 20 min, and 5) 30 min into the recovery period from each session, 6) 9 pm, and 7) 11 pm at night after the session, and 8) immediately after awakening and 9) 15 min and 10) 30 min post-awakening the day after the session (Sampling on Day 4 only upon awakening). Results The results showed that the HIRE session did not change the acute cortisol levels; however, the CAR showed significantly different responses in those who increased (n = 7; Responders) and those who did not increase (n = 6; non-Responders). In addition, a significant negative correlation was found between the rate of increase in area under the curve for the whole of CAR (AUCg) and the amount of change of physical fatigue from control days (Day 1 and 2) to Day 3 and 4 (r = − .478, p = .014). Conclusions These results suggest that both increased and no increased CAR may result from physical adaptation and maladaptation to the HIRE session. Therefore, CAR has the potential to assess the physical adaptation to the loads of local resistance exercise as well, which may help to plan future training loads and recovery.
... Schoenfeld et al. (2015) no observaron diferencias significativas entre los tempos de los entrenamientos analizados. Una ejecución intencionalmente demasiado lenta es contraproducente de cara a la mejora de la hipertrofia por no ser un estímulo adecuado para reclutar la totalidad de UMs de un músculo (principalmente UMs de alto umbral) (Keogh, Wilson y Weatherby, 1999). Los autores especulan sobre la existencia de una posible "velocidad umbral" por debajo de la cual se perjudica la respuesta de hipertrofia. ...
Research
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Revisión de 18 meta-análisis sobre los efectos de la carga externa, las contracciones excéntricas, la frecuencia y volumen de entrenamiento, la restricción de flujo sanguíneo, el entrenamiento aeróbico y la concurrencia con el entrenamiento de fuerza, el orden de los ejercicios, la duración de la ejecución de cada repetición, el momento del día y los modelos de periodización del entrenamiento de fuerza con respecto a las respuestas de hipertrofia muscular.
... 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.
... 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.
... 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]. ...
Article
To optimize/maximize increases on muscle strength and mass in well resistance-trained individuals, the use of resistancetraining (RT) systems have been widely recommended by powerlifters, bodybuilders and coaches. These systems may be characterized as advanced techniques that manipulate specific RT variables emphasizing physiologic mechanisms. However, there is a lack of evidence on literature supporting the advantages of RT systems on muscle strength and mass increases compared with traditional RT performed with constant sets, repetitions and load. It is possible that these equivocal findings are associated with methodological limitations that preclude the correct interpretation of the results. Therefore, the purpose of the present review article was to critically analyze studies and draw conclusions on the effects of RT systems on muscle strength and mass enhancements. The evidence available so far does not allow the determination of wheter RT systems can optimize/maximize increases in muscle strength and mass when compared to traditional RT.
... 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. ...
Article
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). ...
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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). ...
Article
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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.
... 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
There has been considerable debate about the effectiveness of different rest interval lengths on strength gains. OBJECTIVE: The purpose of the current study was to examine the effects of different rest interval durations on upper- and lower-body strength during and after a 16 week resistance training program. Thirty-six recreationally trained men were randomly assigned to one (G1; n = 12), three (G3; n = 12) or five (G5; n = 12) minutes rest interval groups. Each group performed the same program in a nonlinear periodized training model. Maximal strength was assessed at baseline, mid-point (eight weeks) and post-training (16 weeks) for the bench press and leg press exercises. For the bench press, significant increases were demonstrated within G3 and G5 at eight weeks and 16 weeks versus baseline (p < .05). Additionally, G5 (98.2 ± 3.7 kg) was significantly stronger than G1 (92.5 ± 3.8 kg) at 16 weeks (p < .05). For the leg press, significant increases were demonstrated within all groups at eight weeks and 16 weeks versus baseline (p < .05). Additionally, there were significant differences between groups at eight weeks [i.e. G5 (290.8 ± 23.5 kg) significantly stronger than G1 (251.0 ± 15.8 kg); p < .01] and 16 weeks [i.e. G3 (305.0 ± 23.9 kg) and G5 (321.7 ± 21.7 kg) significantly stronger than G1 (276.7 ± 10.7 kg); p < .05]. The findings of the current study indicate that longer rest intervals may result in significantly greater increases in upper and lower body strength after the early weeks of training, when compared to shorter rest intervals. Shorter rest intervals can be effective for strength increases in less trained muscles or exercises; this may apply to advanced athletes following a layoff or novice athletes beginning a resistance training program. Longer rest intervals (up to five minutes) are best applied in highly trained muscles and exercises and the window for adaptation narrows.
... 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.
... 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.
... 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 . ...
... 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.
... 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. ...
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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 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.
... 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.
... 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. ...
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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. ...
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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.
Article
We have investigated the magnitude of circadian variation in Isokinetic and Isometric strength of the knee extensors and flexors, as well as back squat and bench press performance using the MuscleLab force velocity transducer. Ten resistance-trained males (mean±SD: age 21.5 ± 1.1 years; body mass 78.3 ± 5.2 kg; height 1.71 ± 0.07 m) underwent a) three to four familiarization sessions on each dynamometer and b) four sessions at different times of day (03:00, 09:00, 15:00 and 21:00 h). Each session was administered in a counterbalanced order and included a period when Perceived onset of mood states (POMS), then rectal and muscle temperature (Trec, Tm) was measured at rest, after which a 5-min standardized 150 W warm-up was performed on a cycle ergometer. Once completed, Isokinetic (60 and 240°·s-1 for extension and flexion) and Isometric dynamometry with peak torque (PT), time-to-peak-torque (tPT) and peak force (PF) and % activation was measured. Lastly, Trec and Tm were measured before the bench press (at 30, 50 and 70 kg) and back squat (at 40, 60 and 80 kg) exercises. A linear encoder was attached to an Olympic bar used for the exercises and average force (AF), peak velocity (PV) and time-to-peak-velocity (tPV) were measured (MuscleLab software; MuscleLab Technology, Langesund, Norway) during the concentric phase of the movements. Five-min recovery was allowed between each set with three repetitions being completed. General linear models with repeated measures and cosinor analysis were used to analyse the data. Values for Trec and Tm at rest were higher in the evening compared to morning values (Acrophase Φ: 16:35 and 17:03 h, Amplitude A: 0.30 and 0.23°C, Mesor M: 36.64 and 37.43°C, p < 0.05). Vigor, happy and fatigue mood states responses showed Φ 16:11 and 16:03 h and 02:05 h respectively. Circadian rhythms were apparent for all variables irrespective of equipment used where AF, PF and PT values peaked between 16:18 and 18:34 h; PV, tPV and tPT peaked between 05:54 and 08:03 h (p < 0.05). In summary, circadian rhythms in force output (force, torque, power, and velocity) were shown for isokinetic, isometric dynamometers and complex multi-joint movements (using a linear encoder); where tPV and tPT occur in the morning compared to the evening. Circadian rhythms in strength can be detected using a portable, low-cost instrument that shows similar cosinor characteristics as established dynamometers. Hence, muscle-strength can be measured in a manner that is more directly transferable to the world of athletic and sports performance.
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BACKGROUND: Handball is one of the Olympic Games demanding increased physical fitness of its players moderate load training is introduced to these players in order to increase efficiency performance especially throwing velocity. OBJECTIVE: This study was done to find out the effects of moderate load training in the development of throwing velocity among handball players. METHOD: This study is of the quasi experimental design and pre test&post test type and was trained with moderate load. PROCEDURE: The selected subjects were trained with 55%-75% load (moderate load) with Bench press for duration of 6 weeks the improvement in throwing velocity is to be noted. OUTCOME MEASURES: Functional throwing velocity index. RESULTS: The results of the study reveal that there is an improvement.
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En el contexto del entrenamiento con sobrecargas, la duración de la repetición (tempo) hace referencia al tiempo total que dura una sola repetición dentro de una serie de un ejercicio, siendo el resultado de la suma entre la fase concéntrica, isométrica y excéntrica del levantamiento (o viceversa, dependiendo del ejercicio). Ha existido controversia los últimos años respecto a la duración de la repetición (y sus fases) y su impacto en la hipertrofia. El objetivo de esta revisión fue analizar los efectos de programas de entrenamiento donde se hayan comparado distintos tempos de levantamiento y su impacto en la hipertrofia. Se realizó una búsqueda de literatura en la base de datos electrónica Pubmed, con los siguientes criterios de inclusión: i) programas de entrenamiento que induzcan fallo volitivo, ii) que los estudios se hayan realizado bajo acciones dinámicas y con ≥4 semanas de intervención y iii) que los sujetos de estudio sean mayores de 18 años hasta mediana edad. De un total de 473 estudios, cuatro fueron incluidos, donde participaron 113 sujetos (79 hombres y 34 mujeres) y los tempos utilizados variaron entre 1.5 y 90 segundos, con menores tempos asociados a mayor efecto hipertrófico. Un tiempo entre 2 y 6 segundos sería efectivo para inducir adaptaciones hipertróficas.
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The duration of the repetition (tempo) refers to the total time that a single repetition lasts within a set, being the result of the sum between the concentric, isometric and eccentric phase of the lift. There is controversy regarding the duration of the repetition (and its phases) and its impact on muscle hypertrophy. The objective of this review was to analyze the effects of training programs using different lifting tempos and their impact on hypertrophy. METHODOLOGY. A literature search was carried out in the Pubmed electronic database, with the following inclusion criteria: i) training programs that induce volitional failure, ii) studies had been carried out under dynamic actions and with ≥4 weeks of intervention, and iii) the study included participants >18 years of age. RESULTS. From 473 studies, 4 were included, including 79 men and 34 women, and the tempos varied between 1.5 and 90 seconds, with lower tempos associated with greater hypertrophic effect. CONCLUSION. Tempos between 2 and 6 seconds seems effective in inducing hypertrophic adaptations.
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Resistance training protocols performed to muscle failure (MF) have been employed in an attempt to maximize activation and neuromuscular fatigue. Therefore, the aim of this study was to compare the surface electromyography amplitude (EMGRMS) and frequency (EMGFREQ) of the pectoralis major between protocols performed to MF and non muscle failure (NMF). Seven trained men performed three sets at 60% of a repetition maximum, with a 3 min rest period and a 6s repetition duration. MF protocol was performing with maximum number of repetitions in all sets, while in NMF protocol subjects performed 6 repetitions in 3 sets. For data analysis two two-way repeated measures ANOVAs (Protocol x Repetition) were used and when necessary, Bonferroni post hoc was performed. The EMGRMS was higher in the protocol MF compare to NMF, but there was no difference in EMGFREQ between protocols. Although there were no significant differences in the frequency domain between protocols, perform repetitions to MF was a determining factor to generate higher amplitude of the electromyography signal. Thus, perform repetitions to MF could be considered an effective strategy to increase muscle activation in trained individuals, however, with similar neuromuscular fatigue.
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The relationship between force and velocity during resistance training can dictate subsequent gains in strength and hypertrophy. Repetition duration (time elapsed during concentric, eccentric, and rest phases) can be manipulated to maximize force or velocity. Based on this current literature review, variation in repetition duration seems to induce similar changes in strength and/or hypertrophy in both novice and experienced lifters. However, relatively faster repetition durations can produce marginal increases in measures of strength and power, and may be more effective for experienced lifters. Although minimally impactful for untrained populations, manipulating repetition duration may be important for athletes training to maximize transfer to sport.
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Powerlifters train with specialty bars for unstable load (UL) training. For the bench press, the acute effects of UL are mixed, with few studies that examine training interventions. The purpose of this study was to examine the effects of a 6-week bench press training program that uses the Freak Bar (FB) as compared to a traditional barbell (TB) on maximum bench press, peak force, and peak impulse. Seven males and 3 females (21 ± 2.0 yr, 172.2 ± 2.9 cm, and 95.3 ± 20.3 kg) were required to bench press 2 days per week as part of a structured program. On the second bench press day, the FB and TB groups performed 3-position pause bench presses at 60-70% one-repetition maximum (1RM). 1RM, peak force, and peak impulse were measured pre-test and post-test after the 6-week program. Peak force and peak impulse were tested at three bench positions, including the pre-sticking, sticking, and post-sticking points, defined by the distance of the barbell from the chest. Post-training 1RM for the FB group and TB group increased 6.7% (6.78 ± 1.6 kg, p = 0.006) and 4.3% (4.5 ± 2.7 kg, p = 0.23), respectively, with no significant differences between the groups (p = 0.589, ŋ= 0.044). There were no significant differences between the groups at each bench position for peak force (p = 0.606) or peak impulse (p = 0.542). FB can be an alternative for improving maximum strength and peak force but is not significantly better than TB training when performing the 3-position pause bench press.
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The aim of this study was to investigate the impact of protocols equalized by the repetition duration but composed of different concentric and eccentric durations on muscle activation and neuromuscular fatigue. Seventeen males with previous experience in resistance training performed 3 training protocols (A - 2s con : 4s ecc; B - 3s con : 3s ecc; and C - 4s con : 2s 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 (EMGRMS) and mean frequency electromyography (EMGMF) for pectoralis major and triceps brachii muscles were calculated for 2nd and 5th repetitions in each set. The results showed an EMGMF decrease across the repetitions accompanied by a progressive increase of the EMGRMS across the repetitions for all protocols and muscles. The EMGRMS was higher in Protocol C when compared with Protocol A and B for pectoralis major. The EMGMF was lower in Protocols B and C than in Protocol A for pectoralis major throughout the sets and repetitions. A higher EMGRMS and a lower EMGMF were observed in Protocols B and C compared to Protocol A for triceps brachii, solely in the 5th 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.
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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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The bar movement characteristics of 10 elite powerlifters were analyzed while bench pressing a maximum load and a submaximal load in a simulated competition using high-speed cinematography. Significant differences in bar path and alterations to the general force profile of movement were evident as the load was increased. These movement discrepancies resulted in the following conclusions being drawn with reference to the bench press movement: (a) The movement pattern adopted during the performance of an 81 % maximum load was not specific to that which was utilized during the maximal load. (b) Based upon the concepts of specificity of training and testing, the use of the popular one-repetition maximum test to quantify strength changes derived from submaximal training appeared invalid. This occurrence is further accentuated when the testing protocol is conducted on a bench press machine. (c) The design of “isotonic” bench press machines appeared to be load specific. Further, the development of bench press machines that would allow a number of bar paths to be pursued appear to represent a significant improvement over existing models.
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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
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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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Full-text available
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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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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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 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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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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For the athlete or weight trainer who has reached a strength plateau, finding an optimal training program that will stimulate a further strength increase can be a complex problem. The purpose of this study was to compare the effects of two squat training programs utilizing the parallel squat and a functional isometric squat on dynamic strength, static strength and power in college males. Ten subjects enrolled in an advanced power weightlifting class were divided equally into two groups-a functional isometric squat group (FIS), or a dynamic squat group (DS). The subjects trained two days per week for a total of eight weeks, which consisted of a two week pre-conditioning and technique learning period followed by a six week "periodized" functional isometric or dynamic squat training program. Changes in dynamic and static strength were measured with a 1 RM parallel squat and knee extension cable tensiometer test, respectively. Power capacity was assessed by a vertical jump test. Statistically, analysis of the data revealed a significant increase (p < 0.01,) in dynamic strength for both groups. The FIS group, however, realized a statistically greater improvement (p < 0.05) than the DS group. Neither group showed changes in static strength. Both groups made a significant increase (p < 0.05) in power, although the DS group had a statisticaly greater improvement (p < 0.01) than the FIS group (p < 0.05). The results seem to indicate that functional isometric squat training is highly effective in increasing leg strength but not as effective as dynamic squat training for improving jump power. (C) 1989 National Strength and Conditioning Association
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As a consequence of performing plyometric type exercises, such as depth jumps, impact forces placed on the musculoskeletal system during landing can lead to a potential for injury. A reduction of impact forces upon landing could therefore contribute to reduce the risk of injury. Twenty subjects performed a series of loaded jumps for maximal height, with and without a brake mechanism designed to reduce impact force during landing. The braked jumps were performed on the Plyometric Power System (PPS) with its braking mechanism set at 75% of body weight during the downward phase. The non-braked condition involved jumps with no braking. Vertical ground reaction force data, sampled for 5.5 s at 550 Hz from a Kistler forceplate, were collected for each jump condition. The following parameters were then calculated: peak vertical force, time to peak force, passive impact impulse and maximum concentric force. The brake served to significantly (p < 0.01) reduce peak impact force by 155% and passive impact impulse by 200%. No significant differences were found for peak concentric force production. The braking mechanism of the PPS significantly reduced ground impact forces without impeding concentric force production. The reduction in eccentric loading, using the braking mechanism, may reduce the incidence of injury associated with landings from high intensity plyometric exercises.
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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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Skeletal muscle can undergo rapid growth in response to a sudden increase in work load. For example, the rat soleus muscle increases in weight by 40% within six days after the tendon of the synergistic gastrocnemius is sectioned. Such growth of the overworked muscle involves an enlargement of muscle fibers and occasional longitudinal splitting. Hypertrophy leads to greater maximal tension development, although decreased contraction time and reduced contractility have also been reported. Unlike normal developmental growth, work-induced hypertrophy can be induced in hypophysectomized or diabetic animals. This process thus appears independent of growth hormone and insulin as well as testosterone and thyroid hormones. Hypertrophy of the soleus can also be induced in fasting animals, in which there is a generalized muscle wasting. Thus muscular activity takes precedence over endocrine influences on muscle size. The increase in muscle weight reflects an increase in protein, especially sarcoplasmic protein, and results from greater protein synthesis and reduced protein breakdown. Within several hours after operation, the hypertrophying soleus shows more rapid uptake of certain amino acids and synthesis of phosphatidyl-inositol. By 8 hours, protein synthesis is enhanced. RNA synthesis also increases, and hypertrophy can be prevented with actinomycin D. Nuclear DNA synthesis also increases on the second day after operation and leads to a greater DNA content. The significance of the increased RNA and DNA synthesis is not clear, since most of it occurs in interstitial and satellite cells. The proliferation of the non-muscle cells seems linked to the growth of the muscle fibers; in addition, factors causing muscle atrophy (e.g. denervation) decrease DNA synthesis by such cells. In order to define more precisely the early events in hypertrophy, the effects of contractile activity were studied in rat muscles in vitro. Electrical stimulation enhanced active transport of certain amino acids within an hour, and the magnitude of this effect depended on the amount of contractile activity. Stimulation or passive stretch of the soleus or diaphragm also retarded protein degradation. Presumably these effects of mechanical activity contribute to the changes occuring during hypertrophy in vivo. However, under the same conditions, or even after more prolonged stimulation, no change in rates of protein synthesis was detected. These findings with passive tension in vitro are particularly interesting, since passive stretch has been reported to retard atrophy or to induce hypertrophy of denervated muscle in vivo. It is suggested that increased tension development (either passive or active) is the critical event in initiating compensatory growth.
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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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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)
Article
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)
Article
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.