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Muscular Adaptations to Combinations of High- and Low-Intensity Resistance Exercises
Abstract
Acute and long-term effects of resistance-training regimens with varied combinations of high- and low-intensity exercises were studied. Acute changes in the serum growth hormone (GH) concentration were initially measured after 3 types of regimens for knee extension exercise: a medium intensity (approximately 10 repetition maximum [RM]) short interset rest period (30 s) with progressively decreasing load ("hypertrophy type"); 5 sets of a high-intensity (90% of 1RM) and low-repetition exercise ("strength type"); and a single set of low-intensity and high-repetition exercise added immediately after the strength-type regimen ("combi-type"). Postexercise increases in serum GH concentration showed a significant regimen dependence: hypertrophy-type > combi-type > strength-type (p < 0.05, n = 8). Next, the long-term effects of periodized training protocols with the above regimens on muscular function were investigated. Male subjects (n = 16) were assigned to either hypertrophy/combi (HC) or hypertrophy/ strength (HS) groups and performed leg press and extension exercises twice a week for 10 weeks. During the first 6 weeks, both groups used the hypertrophy-type regimen to gain muscular size. During the subsequent 4 weeks, HC and HS groups performed combi-type and strength-type regimens, respectively. Muscular strength, endurance, and cross sectional area (CSA) were examined after 2, 6, and 10 weeks. After the initial 6 weeks, no significant difference was seen in the percentage changes of all variables between the groups. After the subsequent 4 weeks, however, 1RM of leg press, maximal isokinetic strength, and muscular endurance of leg extension showed significantly (p < 0.05) larger increases in the HC group than in the HS group. In addition, increases in CSA after this period also tended to be larger in the HC group than in the HS group (p = 0.08). The results suggest that a combination of high- and low-intensity regimens is effective for optimizing the strength adaptation of muscle in a periodized training program.
... The former consists of high-intensity resistance exercises with low repetitions (>90% of 1RM and 3-5 repetitions) (ST-type), the latter of moderate-intensity resistance exercises with high repetitions (60-80% of 1RM and 8-12 repetitions) (HYP-type). The ST-type training has been shown to improve force-generating capacity due to neural adaptation, with less effect on muscle size [8,9]. On the other hand, the HYP-type training has been shown to increase force-generating capacity as well as muscle size [9,10]. ...
... However, the HYP-type training regimen has the problem of taking a long time to achieve strength gain. As one of the ways to solve this problem, Goto et al. [8] have suggested that, following resistance training for muscle hypertrophy, a combination of high-and low-intensity resistance exercises is effective for simultaneous strength gain and muscle hypertrophy. In an earlier study [8], however, the training-induced change in muscle size was not significant, although the training regimen increased muscular strength. ...
... As one of the ways to solve this problem, Goto et al. [8] have suggested that, following resistance training for muscle hypertrophy, a combination of high-and low-intensity resistance exercises is effective for simultaneous strength gain and muscle hypertrophy. In an earlier study [8], however, the training-induced change in muscle size was not significant, although the training regimen increased muscular strength. ...
It remains unknown whether a regimen of a combination of high- and low-intensity resistance training increases muscle size and maximal voluntary isometric contraction (MVC) simultaneously. This study aimed to clarify the effect of the combination of high- and low-intensity resistance training on muscle size and neuromuscular function in the elbow flexors. Sixteen male adults participated in a 9-week isometric training regimen in elbow joint flexion of each arm. We randomly assigned two different training regimens to left and right arms: one aiming to strengthen maximal strength (ST) and the other aiming to develop muscle size as well as maximal strength, which consists of one contraction to volitional failure with 50% of MVC added to ST (COMB). Following the 3-week training to volitional failure as familiarization, the participants conducted the 6-week ST and COMB training in each arm. Before the intervention, and at the third (Mid) and ninth (Post) weeks, MVC and muscle thickness in the anterior part of the upper arm (ultrasound) were measured. Muscle cross-sectional area (mCSA) was derived from the obtained muscle thickness. From Mid to Post, the relative change in MVC was similar in both arms. The COMB regimen increased muscle size, but no significant change was found in ST. Following the 3-week isometric training to volitional failure, the 6-week training regimen for developing maximal voluntary and muscle hypertrophy increased MVC, with increasing mCSA, and the training-induced change in MVC was similar to that for developing maximal voluntary strength alone.
... The length of rest interval between sets (i.e., inter-set rest interval) is an important variable for resistance exercise program. Previous studies have reported that short rest interval (SRI) protocol may be more useful to enhancing resistance training-induced muscle adaptation (e.g., muscle hypertrophy and strength gain) than long rest interval (LRI) protocol (Takarada and Ishii, 2002;Goto et al., 2004). This positive effect of long-term resistance exercise with SRI may be at least partially due to increased levels of by-products such as lactate during an acute bout of this protocol (Kraemer et al., 1990(Kraemer et al., , 1993. ...
... This study employed 1-min inter-set rest intervals for SRI protocol, as in many previous studies (see a review by de Salles et al., 2009). Nevertheless, some previous studies used inter-set rest intervals shorter than 1 min (i.e., 30 s; Takarada and ishii, 2002;Goto et al., 2004). Furthermore, we employed 40% 1-RM for carrying out low-intensity resistance exercise based on our previous study (Tsukamoto et al., 2017a), while most previous studies examining resistance exercise with SRI used exercise loads heavier than 40% 1-RM (see a review by de Salles et al., 2009). ...
... Previous studies have reported that increases in circulating endocrine responses induced by acute bout of resistance exercise were greater with SRI protocol than with LRI protocol (Kraemer et al., 1990(Kraemer et al., , 1993Goto et al., 2004). A series of studies by Kraemer et al. (1990Kraemer et al. ( , 1993 reported that resistance exerciseinduced increases in growth hormone were greater following SRI protocol than following LRI protocol. ...
The length of rest interval between sets (i.e., inter-set rest interval) is an important variable for resistance exercise program. However, the impact of the inter-set rest interval on improvements in cognitive function following resistance exercise remains unknown. In this study, we compared the effect of short rest interval (SRI) vs. long rest interval (LRI) protocols on post-exercise cognitive inhibitory control (IC) improvements induced by low-intensity resistance exercise. Twenty healthy, young males completed both SRI and LRI sessions in a crossover design. The bilateral knee extensor low-intensity resistance exercise was programed for six sets with 10 repetitions per set using 40% of one-repetition maximum. The inter-set rest interval lengths for SRI and LRI protocols were set for 1 and 3min, respectively. The color-word Stroop task (CWST) was administrated at six time points: baseline, pre-exercise, immediate post-exercise, and every 10min during the 30-min post-exercise recovery period. The levels of blood lactate, which may be an important determinant for improving IC, throughout the 30-min post-exercise recovery period were significantly higher following SRI protocol than following LRI protocol ( p =0.002 for interaction effect). In line with this result, large-sized decreases in the reverse-Stroop interference score, which represent improved IC, were observed immediately after SRI protocol ( d =0.94 and 0.82, respectively, vs. baseline and pre-exercise) as opposed to the moderate-sized decreases immediately after LRI protocol ( d =0.62 and 0.66, respectively, vs. baseline and pre-exercise). Moreover, significant decreases in the reverse-Stroop interference score were observed from 10 to 30min after SRI protocol (all p s<0.05 vs. baseline and/or pre-exercise), whereas no such decrease was observed after LRI protocol. Furthermore, the degree of decreases in the reverse-Stroop interference score throughout the 30-min post-exercise recovery period was significantly greater in SRI protocol than in LRI protocol ( p =0.046 for interaction effect). We suggest that the SRI protocol is more useful in improving post-exercise IC, potentially via greater circulating lactate levels, compared to the LRI protocol. Therefore, the inter-set rest interval length may be an important variable for determining the degree of cognitive function improvements following resistance exercise in healthy young males.
... Recently, novel training methods in which a load or intensity reduction occurs within a training protocol have been studied, and research suggests that these methods may simultaneously elicit muscular strength, muscular hypertrophy, and muscular endurance outcomes but that more research is needed to support these conclusions (28). The back-off or down set strategy has also been used similarly to induce strength, hypertrophy, and muscular endurance outcomes (17). Back-off sets are a strategy that follows the current literature's recommendations in that training to failure and nonfailure training can produce similar outcomes in muscle strength and hypertrophy, and that the outcomes of these training types may depend on factors such as fatigue management and training status (6,7,11,20,21,30,31,35,41,43). ...
... Research has shown back-off sets have a capacity to yield hypertrophy, strength, and muscular endurance adaptations (17). Other research suggests that back-off sets may have neural, mechanical, and autoregulatory benefits; however, the evidence for these benefits is limited (10,25) ( Table 2). ...
... Although research supports using RPE to adjust training load and quantifying training volume as total number of sets at or near failure, there is less evidence to support using this method to adjust training volume and therefore more research is needed to conclude the efficacy of using RPE to adjust training volume (18).If muscle hypertrophy has a degree of a dose-response relationship to hard sets, then the improvements seen from using back-off sets may be a result of comparatively greater training volume achieved by the back-off set groups. Research suggests that back-off set conditions or groups have generally completed greater training volume than those studies controls or other respective conditions (1,10,17). Investigations have primarily used back-off sets as a way to increase training volume, although there may exist other benefits to using back-off sets. ...
Back-off sets or down sets are a training paradigm that use an initial heavy loaded set followed by a subsequent rest period and a planned load reduction. Back-off sets are a way to maintain or increase training volume through a load reduction for subsequent sets. By reducing load, a desired number of repetitions can be achieved as opposed to a reduction in volume that would occur if a consistent load was maintained. Back-off sets have been shown to allow completion of a greater training volume which may be in part due to a potentiation effect. The use of back-off sets help to reduce the necessary length of interset rest periods. Back-off set utility may be influenced by factors including but not limited to training goals, training age, exercise type, protocol individualization, loading strategy, load-reduction strategy, and autoregulation. This discussion aims to provide an overview of the integration of back-off sets within resistance training programs by examining previous research and providing a synopsis of the variables that impact the efficacy of this strategy.
... Schoenfeld and Grgic (7) noted recently that muscles are not completely fatigued at concentric muscular failure, and the muscles are still capable of producing additional repetitions if the resistance is reduced. They cited and discussed the methods and results of five training studies (8)(9)(10)(11)(12)) that compared the efficacy of a drop-set training protocol with different traditional resistance training protocols. None of those studies reported a significant difference in training induced muscle hypertrophy between drop-set training and traditional training. ...
... Schoenfeld and Grgic (7) specifically described the study by Goto and colleagues (8) in an attempt to show some advantage to drop-set training. The f o r p e r s o n a l u s e o n l y d o u ż y t k u p r y w a t n e g o statement by Schoenfeld and Grgic that the subjects were recreationally trained was misleading. ...
... Schoenfeld and Grgic (7) claimed also that the drop-set group increased thigh muscularity by another 2% during the next 4 weeks. However, Goto and colleagues (8) reported that neither group showed a significant change in muscle hypertrophy during the last 4 weeks (p = 0.08). As previously noted, none of the studies that Schoenfeld and Grgic cited in their article supported the efficacy of drop-set resistance training. ...
Researchers have expressed concern recently for standardization of resistance training protocols so that valid comparisons of different training variables such as muscular fatigue, time under tension, pre-exhaust exercise and exercise order, pyramid and drop sets, amount of resistance (load), range of repetitions, frequency and volume of exercise, interset rest intervals, etc. can be more closely studied and compared. This Critical Commentary addresses some recent review articles and training studies specifically focused on the stimulus for muscle hypertrophy in participants with several years of resistance training experience. It reveals that many of the recommended resistance training protocols have their foundation in some long-held, self-described bias. Blinding of assessors and statisticians, self-plagiarism, authorship responsibility, and conflicts of interest are briefly discussed as well. The conclusion is that most of the published peer-reviewed resistance training literature failed to provide any compelling evidence that the manipulation of any one or combination of the aforementioned variables can significantly affect the degree of muscle hypertrophy, especially in well-trained participants. Although the specific stimulus for optimal gains in muscle mass is unknown, many authors are desperately clinging to their unsupported belief that a greater volume of exercise will produce superior muscle hypertrophy.
... Dažnai pasirenkami judrieji žaidimai, leidžiantys įvairinti mokinių judėjimo kultūrą. Literatūroje nurodoma, kad žaisdamas vaikas (paskui jaunuolis) lavinasi fi-ziškai, t. y. jis lavina ne tik raumenis (Dineika, Mantvila, 1934), bet ir didina sąnarių paslankumą, teigiamai veikia kvėpavimo sistemą, gerina organizmo medžiagų apykaitą, o, svarbiausia, lavina fizines ypatybes -vikrumą, greitumą, lankstumą, jėgą, ištvermę, šoklumą (Šeibokas, 1999;Rankinis, 1999;Stonkus ir kt., 2002;Džiuvė, 2003), didina vaiko judėjimo galias (Goto et al., 2004;Hadzovic et al., 2004), tobulina koordinacijos mechanizmus, sudaro palankias sąlygas išmokti vis naujų judesių (Ivaškienė, 2002;Reed et al., 2004). ...
... Dažnai pasirenkami judrieji žaidimai, leidžiantys įvairinti mokinių judėjimo kultūrą. Literatūroje nurodoma, kad žaisdamas vaikas (paskui jaunuolis) lavinasi fi-ziškai, t. y. jis lavina ne tik raumenis (Dineika, Mantvila, 1934), bet ir didina sąnarių paslankumą, teigiamai veikia kvėpavimo sistemą, gerina organizmo medžiagų apykaitą, o, svarbiausia, lavina fizines ypatybes -vikrumą, greitumą, lankstumą, jėgą, ištvermę, šoklumą (Šeibokas, 1999;Rankinis, 1999;Stonkus ir kt., 2002;Džiuvė, 2003), didina vaiko judėjimo galias (Goto et al., 2004;Hadzovic et al., 2004), tobulina koordinacijos mechanizmus, sudaro palankias sąlygas išmokti vis naujų judesių (Ivaškienė, 2002;Reed et al., 2004). ...
... Judrieji žaidimai kūno kultūros pamokose gali būti panaudojami kaip viena iš efektyviausių priemonių lavinant mokinių fizines ypatybes (Rankinis, 1999;Šeibokas, 1999;Džiuvė, 2003). Atlikto tyrimo rezultatai sutampa su mokslinės literatūros teiginiais, nurodančiais, kad judrieji žaidimai yra tinkama priemonė vaikų fizinėms ypatybėms lavinti (Rankinis, 1999;Šeibokas, 1999;Džiuvė, 2003). ...
Siūlomi įvairūs metodai ir priemonės mokinių fizinėms ypatybėms lavinti, tačiau, daugelio autorių nuomone, jaunesnio
mokyklinio amžiaus vaikams šiuo požiūriu labiausiai tinka judrieji žaidimai. Tyrimo tikslas — nustatyti, kaip ilgesnė
judriųjų žaidimų trukmė kūno kultūros pamokose veikia berniukų greitumo bei jėgos ypatybių lavėjimą, ir įvertinti
liekamuosius pagerėjimo efektus po vienerių metų. Buvo tiriami 67 šeštų ir septintų klasių (12—13 metų) berniukai.
Atsitiktiniu būdu jie suskirstyti į dvi grupes — eksperimentinę ir kontrolinę. Eksperimentinės grupės berniukai per kūno
kultūros pamokas (po 20 min) žaidė judriuosius žaidimus, skirtus jėgos ir greitumo ypatybėms lavinti. Kontrolinės
grupės berniukai turėjo įprastas kūno kultūros pamokas. Tyrimu įvertinta, kaip ilgesnė judriųjų žaidimų trukmė veikia
greitumo ir jėgos ypatybes, kaip kinta galūnės judesio greitis, vikrumas, staigioji jėga, ir kaip taikyti judrieji žaidimai
veikia atskirų raumenų grupių (rankų, pilvo preso, nugaros ir kojų raumenų) greitumo ir jėgos ypatybes. Tyrimo
rezultatai parodė, kad padidinus judriųjų žaidimų trukmę kūno kultūros pamokose pagerėjo galūnės judesio greitis
bei pasireiškė ryški vikrumo ir staigiosios jėgos gerėjimo tendencija. Judrieji žaidimai nevienareikšmiškai veikia
atskirų raumenų grupių jėgos ir greitumo ypatybes: daugiausia lavėja kojų raumenų jėga, pagerėja rankų raumenų
greitumas, lavėja nugaros raumenų jėgos ir greitumo ypatybės, tačiau nepastebėta pilvo preso raumenų greitumo ir
jėgos ypatybių gerėjimo. Trumpalaikė (penkių savaičių) ilgesnė judriųjų žaidimų trukmė kūno kultūros pamokose yra
nepakankama, kad sukeltų ilgalaikės adaptacijos efektą.
Raktažodžiai: kūno kultūros pamoka, judrieji žaidimai, greitumas, jėga.
... Given that attenuation of blood pressure increase prevents resistance exercise-induced endothelial dysfunction (3), minimizing barostress on the vasculature is key to counteracting the detrimental effects of resistance exercise. At this point, high-intensity resistance exercise with low repetitions is commonly used to improve muscle strength (13). Because of low repetitions and long resting period between sets, the endocrine response is relatively mild (14), and the elevation in blood pressure is temporal (18) compared with that effected by moderate-intensity resistance exercise. ...
... Resting periods among all sets were 60, 60, and 180 s, respectively. These percentages of 1RM were chosen as typical intensities of resistance exercise for each trial (4,12,13). Intensity during the resistance exercise was adjusted to allow the subjects to complete 10, 40, and 3 repetitions in each set (~70%, 30%, or 85% of 1RM for the first set). Systolic and diastolic blood pressures were measured during resting period between sets. ...
... Previous studies have observed that, during moderate-intensity resistance exercise with moderate repetitions and lowintensity resistance exercise with high repetitions, there is a marked and sustained elevation in arterial blood pressure in the artery during resistance exercise that subsequently leads to endothelial dysfunction (13,14,17,18,20). Recently, Buchanan et al. (3) conducted a study that was designed to prevent a marked elevation in artery blood pressure through cuff inflation on the upper arm during exercise. ...
Resistance exercise impairs endothelial function, and this impairment is thought to be mediated by sustained elevation in blood pressure. Herein, we tested the hypothesis that resistance exercise-induced endothelial dysfunction would be prevented by high-intensity resistance exercise with low repetitions. This type of resistance exercise is known to induce temporal elevation in blood pressure due to low repetitions and a long resting period between sets. Thirteen young healthy subjects completed three randomized experimental trials as follows: 1) moderate-intensity exercise with moderate repetitions (moderate-moderate trial), 2) low-intensity exercise with high repetitions (low-high trial), and 3) high-intensity exercise with low repetitions (high-low trial). After baseline brachial artery flow-mediated dilation (FMD) and blood pressure measurements, subjects performed resistance exercise according to the different types of trials. Thereafter, brachial artery FMD and blood pressure measurements were repeated 10, 30, and 60 min after the exercise. Exercise-induced increases in blood flow and shear rate were significantly lower in the high-low trial than in the other two trials ( P < 0.05). Although systolic blood pressures were significantly elevated after exercise in all trials ( P < 0.05), the magnitudes of rise in blood pressure increase were significantly lower in the high-low trial than in the moderate-moderate and low-high trials ( P < 0.05). Moderate-moderate and low-high trials caused a significant impairment in brachial artery FMD ( P < 0.05), which could be prevented through high-intensity resistance exercise with low repetitions ( > 0.05). In conclusion, endothelial function was maintained by conducting high-intensity resistance exercise with low repetitions.
NEW & NOTEWORTHY Data from the present study reveal that high-intensity resistance exercise with low repetitions can maintain endothelial function. Thus, this study provides the first evidence that the detrimental vascular effects of resistance exercise are preventable when resistance exercise is performed in high intensity with low repetitions.
Listen to this article’s corresponding podcast at https://ajpheart.podbean.com/e/type-of-resistance-exercise-and-endothelial-function/ (Japanese version: https://ajpheart.podbean.com/e/japanese-language-podcast-type-of-resistance-exercise-and-endothelial-function/ ).
... Chronic effects of drop-set RT In a longitudinal design, Goto et al. [107] concluded that strength training (5 sets, 90 % of 1-RM) and strength training with the addition of one drop set (25-35 repetitions with 40-50 % of 1-RM) both led to significant increases in endurance, strength, and rate of force development. However, the drop-set group had significantly greater increases in 1-RM for leg press, maximal isokinetic strength at a fast velocity (e.g., 300 degrees/second), and muscular endurance, which was quantified as total work performed (load x repetitions) during one set of knee-extension to failure with 30 % of maximal voluntary contraction [107]. ...
... Chronic effects of drop-set RT In a longitudinal design, Goto et al. [107] concluded that strength training (5 sets, 90 % of 1-RM) and strength training with the addition of one drop set (25-35 repetitions with 40-50 % of 1-RM) both led to significant increases in endurance, strength, and rate of force development. However, the drop-set group had significantly greater increases in 1-RM for leg press, maximal isokinetic strength at a fast velocity (e.g., 300 degrees/second), and muscular endurance, which was quantified as total work performed (load x repetitions) during one set of knee-extension to failure with 30 % of maximal voluntary contraction [107]. Because total training volume was not matched, it is difficult to conclude if the differences between groups occurred strictly because of the metabolic stress imposed by the drop-set condition. ...
Generally, skeletal muscle adaptations to exercise are perceived through a dichotomous lens where the metabolic stress imposed by aerobic training leads to increased mitochondrial adaptations while the mechanical tension from resistance training leads to myofibrillar adaptations. However, there is emerging evidence for cross over between modalities where aerobic training stimulates traditional adaptations to resistance training (e.g., hypertrophy) and resistance training stimulates traditional adaptations to aerobic training (e.g., mitochondrial biogenesis). The latter is the focus of the current review in which we propose high-volume resistance training (i.e., high time under tension) leads to aerobic adaptations such as angiogenesis, mitochondrial biogenesis, and increased oxidative capacity. As time under tension increases, skeletal muscle energy turnover, metabolic stress, and ischemia also increase, which act as signals to activate the peroxisome proliferator-activated receptor gamma coactivator 1-alpha, which is the master regulator of mitochondrial biogenesis. For practical application, the acute stress and chronic adaptations to three specific forms of high-time under tension are also discussed: Slow-tempo, low-intensity resistance training, and drop-set resistance training. These modalities of high-time under tension lead to hallmark adaptations to resistance training such as muscle endurance, hypertrophy, and strength, but little is known about their effect on traditional aerobic training adaptations.
... The general recommendation of high-volume, moderate-to-high intensity programs utilizing short rest intervals was based on empirical evidence suggesting that this training paradigm is typically used by bodybuilders (Hackett et al. 2013) during hypertrophy phases of periodized training for athletes , and by studies reporting greater increases in muscle hypertrophy as training volume (i.e., number of sets performed) increases (Kraemer 1997;Kraemer et al. 2000;Marx et al. 2001;Goto et al. 2004). Although major health organizations such as the American College of Sports Medicine have recommended a multitude of loading and volume strategies in a periodized manner for advanced hypertrophy training, the moderate-to-high intensity range (6-12 RM) has been regarded as an effective hypertrophy training zone that thought to provide a sufficient balance of mechanical and metabolic stress to the trainee . ...
... This contrasts with previous investigations which showed that the mechanical and metabolic stresses of high-volume and high-intensity training programs provided a similar stimulus for muscle growth in trained participants (Brandenburg and Docherty 2002;Schoenfeld et al. 2014). These differences may be explained, in part, by the level of tissue activation associated with the exercise selection (Tipton et al. 2001;Goto et al. 2004). Notably, the limited number of multiple joint structural exercises used per training session in those studies. ...
... Furthermore, the study did not compare the effects of DS with TRAD and assessed only one microvascular oxygenation parameter. Additionally, other studies (15,16) concluded that a protocol that most closely resembles DS (i.e., a set performed until muscle failure after a short pause at the end of the training session) produced higher increases in indirect indicators of metabolic stress (e.g., lactate and growth hormone [GH]) compared with TRAD. Therefore, despite no study compared the effects of DS on microvascular oxygenation with TRAD, it is conceivable that higher volume inherent to DS would produce higher microvascular oxygenation changes compared with TRAD. ...
... Accordingly, the DS protocol used herein produced a greater number of repetitions than TRAD and CP (i.e., TRAD = 30 ± 0 reps; DS = 64 ± 7 reps; CP = 24 ± 0 reps), allowed by the load "drops" after a very short rest resulting in greater TTV (Fig. 3), what may explain the greater changes not only in HHb, but also in HbO2 and HbDiff. In fact, studies (15,16) showed higher increases in indirect indicators of metabolic stress (i.e., lactate and growth hormone [GH]) which are speculated be related to changes on microvascular oxygenation status (38) in a protocol that resembles DS (i.e., additional sub-set to concentric failure after reducing load in the last set, resulting in a higher TTV compared with TRAD). Therefore, we suggest that the specificity of the DS protocol (i.e., large number of repetitions resulting in greater TTV than other tested RT protocols) resulted in higher microvascular oxygenation changes compared with TRAD and CP. ...
Metabolic stress is a primary mechanism of muscle hypertrophy and is associated with microvascular oxygenation and muscle activation. Considering that drop-set (DS) and crescent pyramid (CP) resistance training systems are recommended to modulate these mechanisms related to muscle hypertrophy, we aimed to investigate if these resistance training systems produce a different microvascular oxygenation status and muscle activation from those observed in traditional resistance training (TRAD). Twelve volunteers had their legs randomized in an intra-subject cross-over design in TRAD (3 sets of 10 repetitions at 75% 1-RM), DS (3 sets of ∼50-75% 1-RM) and CP (3 sets of 6-10 repetitions at 75-85% 1-RM). Vastus medialis microvascular oxygenation and muscle activation were respectively assessed by non-invasive near-infrared spectroscopy and surface electromyography techniques during the resistance training sessions in the leg-extension exercise. Total hemoglobin area under the curve (AUC) (TRAD: -1653.5 ± 2866.5; DS: -3069.2 ± 3429.4; CP: -1196.6 ± 2675.3) and tissue oxygen saturation (TRAD: 19283.1 ± 6698.0; DS: 23995.5 ± 15604.9; CP: 16109.1 ± 8553.1) increased without differences between protocols (p>0.05). Greater decreases in oxygenated hemoglobin AUC and hemoglobin differentiated AUC were respectively found for DS (-4036.8 ± 2698.1; -5004.4 ± 2722.9) compared with TRAD (-1951.8 ± 1720.0; -2250.3 ± 1305.7) and CP (-1814.4 ± 2634.3; 2432.2 ± 2891.4) (p<0.03). Higher increases of hemoglobin deoxygenated AUC were found for DS (1426.7 ± 1320.7) compared with TRAD (316.0 ± 1164.9) only (p=0.04). No differences were demonstrated in electromyographic amplitudes between TRAD (69.0 ± 34.4), DS (61.3 ± 26.7) and CP (60.9 ± 38.8) (p>0.05). Despite DS produced lower microvascular oxygenation levels compared with TRAD and CP, all protocols produced similar muscle activation levels.
... Schoenfeld and Grgic (7) noted recently that muscles are not completely fatigued at concentric muscular failure, and the muscles are still capable of producing additional repetitions if the resistance is reduced. They cited and discussed the methods and results of five training studies (8)(9)(10)(11)(12)) that compared the efficacy of a drop-set training protocol with different traditional resistance training protocols. None of those studies reported a significant difference in training induced muscle hypertrophy between drop-set training and traditional training. ...
... Schoenfeld and Grgic (7) claimed also that the drop-set group increased thigh muscularity by another 2% during the next 4 weeks. However, Goto and colleagues (8) reported that neither group showed a significant change in muscle hypertrophy during the last 4 weeks (p = 0.08). As previously noted, none of the studies that Schoenfeld and Grgic cited in their article supported the efficacy of drop-set resistance training. ...
Researchers have expressed concern recently for standardization of resistance training protocols so that valid comparisons of different training variables such as muscular fatigue, time under tension, pre-exhaust exercise and exercise order, pyramid and drop sets, amount of resistance (load), range of repetitions, frequency and volume of exercise, interset rest intervals, etc. can be more closely studied and compared. This Critical Commentary addresses some recent review articles and training studies specifically focused on the stimulus for muscle hypertrophy in participants with several years of resistance training experience. It reveals that many of the recommended resistance training protocols have their foundation in some long-held, self-described bias.
... Schoenfeld and Grgic (7) noted recently that muscles are not completely fatigued at concentric muscular failure, and the muscles are still capable of producing additional repetitions if the resistance is reduced. They cited and discussed the methods and results of five training studies (8)(9)(10)(11)(12)) that compared the efficacy of a drop-set training protocol with different traditional resistance training protocols. None of those studies reported a significant difference in training induced muscle hypertrophy between drop-set training and traditional training. ...
... Schoenfeld and Grgic (7) claimed also that the drop-set group increased thigh muscularity by another 2% during the next 4 weeks. However, Goto and colleagues (8) reported that neither group showed a significant change in muscle hypertrophy during the last 4 weeks (p = 0.08). As previously noted, none of the studies that Schoenfeld and Grgic cited in their article supported the efficacy of drop-set resistance training. ...
Researchers have expressed concern recently for standardization of resistance training protocols so that valid comparisons of different training variables such as muscular fatigue, time under tension, pre-exhaust exercise and exercise order, pyramid and drop sets, amount of resistance (load), range of repetitions, frequency and volume of exercise, interset rest intervals, etc. can be more closely studied and compared. This Critical Commentary addresses some recent review articles and training studies specifically focused on the stimulus for muscle hypertrophy in participants with several years of resistance training experience. It reveals that many of the recommended resistance training protocols have their foundation in some long-held, self-described bias.
... Both groups performed their respective protocols twice a week for 8 weeks. For N-IND, WTV was determined based on the average number of sets per muscle group (22 6 6.3) prescribed for resistance-trained subjects in 20 randomly selected studies (2,4,7,9,11,(18)(19)(20)(21)(22)(23)25,(32)(33)(34)(35)37,38,41,42). The WTV for N-IND was, thus, determined as 22 sets per week. ...
... A sample of RT-induced muscle hypertrophy (2,4,7,9,11,(18)(19)(20)(21)(22)(23)25,(32)(33)(34)(35)37,38,41,42) showed a large variability in the number of sets (22 6 6.3) prescribed for welltrained individuals. A study by Hackett et al. (12) in which 127 competitive male bodybuilders were surveyed during the offseason period, 74% of them performed 4-5 exercises per muscle group, and 95.3% performed 3-6 sets per exercise per week. ...
Scarpelli, MC, Nóbrega, SR, Santanielo, N, Alvarez, IF, Otoboni, GB, Ugrinowitsch, C, and Libardi, CA. Muscle hypertrophy response is affected by previous resistance training volume in trained individuals. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to compare gains in muscle mass of trained individuals after a resistance training (RT) protocol with standardized (i.e., nonindividualized) volume (N-IND), with an RT protocol using individualized volume (IND). In a within-subject approach, 16 subjects had one leg randomly assigned to N-IND (22 sets·wk, based on the number of weekly sets prescribed in studies) and IND (1.2 × sets·wk recorded in training logs) protocols. Muscle cross-sectional area (CSA) was assessed by ultrasound imaging at baseline (Pre) and after 8 weeks (Post) of RT, and the significance level was set at p < 0.05. Changes in the vastus lateralis CSA (difference from Pre to Post) were significantly higher for the IND protocol (p = 0.042; mean difference: 1.08 cm; confidence interval [CI]: 0.04-2.11). The inferential analysis was confirmed by the CI of the effect size (0.75; CI: 0.03-1.47). Also, the IND protocol had a higher proportion of individuals with greater muscle hypertrophy than the typical error of the measurement (chi-square, p = 0.0035; estimated difference = 0.5, CI: 0.212-0.787). In conclusion, individualizing the weekly training volume of research protocols provides greater gains in muscle CSA than prescribing a group standard RT volume.
... Eight studies were, therefore, assessed for eligibility [14-18, 20, 29, 30]. One study was excluded because of the study design [30], and another was excluded because the data had been used [20]. One study was excluded from the quantitative synthesis due to lack of information [29]. ...
Abstract Background One of the most popular time-efficient training methods when training for muscle hypertrophy is drop sets, which is performed by taking sets to concentric muscle failure at a given load, then making a drop by reducing the load and immediately taking the next set to concentric or voluntary muscle failure. The purpose of this systematic review and meta-analysis was to compare the effects of drop sets over traditional sets on skeletal muscle hypertrophy. Methods This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The SPORTDiscus and MEDLINE/PubMed databases were searched on April 9, 2022, for all studies investigating the effects of the drop set training method on muscle hypertrophy that meets the predefined inclusion criteria. Comprehensive Meta-Analysis Version 3 (Biostat Inc., Englewood Cliffs, NJ, USA) was used to run the statistical analysis. Publication bias was assessed through visual inspection of the funnel plots for asymmetry and statistically by Egger’s regression test with an alpha level of 0.10. Results Six studies met the predefined inclusion criteria. The number of participants in the studies was 142 (28 women and 114 men) with an age range of 19.2–27 years. The average sample size was 23.6 ± 10.9 (range 9–41). Five studies were included in the quantitative synthesis. Meta-analysis showed that both the drop set and traditional training groups increased significantly from pre- to post-test regarding muscle hypertrophy (drop set standardized mean difference: 0.555, 95% CI 0.357–0.921, p
... Regarding the role of MSTN and FLST in the response to resistance training, studies have shown that MSTN plasma levels decrease after several weeks of resistance training, whereas FLST concentrations increase after resistance training [28][29][30]. Activated muscle mass is a key determinant of endocrine anabolic hormone responses to resistance training [31,32]. Mourkioti et al. showed that FLST levels increase depending on the volume of active muscle groups [33]. ...
A rest–pause (RP) technique involves performing one or more repetitions at high resistance to failure, followed by a short rest before performing one or more repetitions. These techniques can affect neuromuscular conditions and fatigue by changing the rest time between repetitions. This study compared the effect of 12 weeks of RP and traditional resistance training (TRT) on myokines (myostatin (MSTN), follistatin (FLST) and insulin-like growth factor-1 (IGF-1)) and functional adaptations. The study recruited 29 men between the ages of 20 and 30 who had performed resistance training for at least 6 to 12 months. Participants were randomly divided into three groups: RP, TRT, and control; resistance training was performed 3 days per week for 12 weeks. The training methods of the two groups were largely similar. The results showed that RP increased IGF-1 and FLST/MSTN more than the TRT group (% change = 19.04, % change = 37.71), and only the RP and TRT groups had significant changes in the FLST/MSTN ratio compared to the control group (p < 0.001 and p = 0.02, respectively). In addition, FLST levels increased and MSTN decreased in the RP and TRT groups, but the rate of change in FLST was significant in the RP and TRT groups compared to the control group (p = 0.002 and p = 0.001, respectively). Leg press and bench press strength, and arm and thigh muscular cross-sectional area (MCSA) increased more in the RP group than in the others, and the percentage of body fat (PBF) decreased significantly. The change between strength and MCSA was significant (p ≤ 0.05), and the PBF change in RP and TRT compared to the control (ES RP group = 0.43; ES TRT group = 0.55; control group ES = 0.09) was significant (p = 0.005, p = 0.01; respectively). Based on the results, the RP training technique significantly affects strength and muscle hypertrophy more than the TRT method, which can be included in the training system to increase strength and hypertrophy.
... Dodatni efekat metaboličkom stresu daje i mišićna ishemija, koja zajedno sa glikolitičkim treningom izazivaju hormonske promene, povećanu hidrataciju ćelije, povećavaju aktivnost faktora rasta i stvaranje slobodnih radikala (Goto, et al., 2005;Takarada, et al., 2000). Pretpostavlja se da visoka koncentracija vodonikovih jona povećava degradacioni proces i stimulira simpatičku nervnu aktivnost i povećava adaptivni hipertrofički odgovor (Goto, et al., 2004). ...
The aim of this paper is to determine the state of the football player before starting
preparations for the upcoming half-season. The sample consisted of 18 players of the third federal rank. The subjects were first measured body height (anthropometer) and then the body composition using the Inbody 770 instrument. Subsequently, tests were performed to assess the explosive leg power (CMJ, CMJa, SJ) using an instrument Optojump, agility (9-6-3- 6-9, sprint 20m) and endurance (Yo-Yo endurance). Correlations have shown that there is a correlation between BMI and agility tests. The percentage of body fat and body fat in kilograms correlated with CMJ and sprint in all three stages. After the research, the level of readiness of athletes was determined and an adequate plan and program of the training process will be developed in order to achieve the best possible results in the upcoming period.
... For standardization of the movements, the volunteers were instructed to follow a rhythm of 2 s for concentric actions and 4 s for eccentric actions at a 60 s cadence during the training session. In this way, the participant remained in eccentric action longer, aiming at causing greater muscle damage [36]. The number of repetitions and the weight lifted in each series were recorded. ...
The objective of this study was to verify the influence of the ACTN3 R577X polymorphism on muscle damage and the inflammatory response after an acute strength training (ST) session. Twenty-seven healthy male individuals (age: 25 ± 4.3 years) participated in the study, including 18 RR/RX and 9 XX individuals. The participants were divided into two groups (RR/RX and XX groups) and subjected to an acute ST session, which consisted of a series of leg press, leg extension machine, and seated leg curl machine. The volunteers were instructed to perform the greatest volume of work until concentric muscle failure. Each volunteer’s performance was analyzed as the load and total volume of training, and the blood concentrations of C-C motif chemokine ligand 2 (CCL2), interleukin-8 (IL-8), creatine kinase (CK), lactate dehydrogenase (LDH), myoglobin, testosterone, and cortisol were measured before the ST session and 30 min and 24 h postsession. The ACTN3 R577X polymorphism effect was observed, with increased concentrations of CCL2 ( p < 0.01 ), IL-8 ( p < 0.01 ), and LDH ( p < 0.001 ) in XX individuals. There was an increase in the concentration of CK in the RR/RX group compared to XX at 24 h after training ( p > 0.01 ). The testosterone/cortisol ratio increased more markedly in the XX group ( p < 0.001 ). Regarding performance, the RR/RX group presented higher load and total volume values in the training exercises when compared to the XX group ( p < 0.05 ). However, the XX group presented higher values of delayed onset muscle soreness (DOMS) than the RR/RX group ( p < 0.05 ). The influence of ACTN3 R577X polymorphism on muscle damage and the inflammatory response was observed after an acute ST session, indicating that the RR/RX genotype shows more muscle damage and a catabolic profile due to a better performance in this activity, while the XX genotype shows more DOMS.
... Muscle ischemia has an additional effect on metabolic stress, which together with glycolytic training causes hormonal changes, increased cell hydration, increased growth factor activity and free radical formation (Goto, et al., 2005;Takarada, et al., 2000). High concentrations of hydrogen ions are thought to increase the degradation process and stimulate sympathetic nerve activity and increase the adaptive hypertrophic response (Goto, et al., 2004). ...
... Longitudinal research is currently limited as to the effects of drop set training on muscular adaptations of the lower limb. Seminal work by Goto et al. [6] provided preliminary support for the strategy, showing significantly greater increases in one repetition maximum (RM) leg press and maximal isokinetic knee extension torque for a group performing a single drop set to MMF using 50% one RM compared to a traditional set configuration. Moreover, the drop set group realized a~2% increase in thigh muscle cross sectional area whereas the traditional group displayed a slight loss in muscle size (~0.5%), ...
The study aimed to compare the effects of drop set resistance training (RT) versus traditional
RT on markers of maximal muscle strength and regional hypertrophy of the quadriceps femoris.
Sixteen recreationally active young men had one leg randomly assigned to the drop-set method
(DS) and the other to training in a traditional manner (TRAD). Participants performed unilateral
seated leg extensions using a periodized approach for eight weeks. Rectus femoris (RF) and vastus
lateralis (VL) muscle thickness (MT), estimated one repetition maximum (RM) in the unilateral knee
extension, and peak and average isokinetic knee extension torque at 60◦/s angular velocity were
measured pre- and post-study. Both conditions increased muscle thickness of the RF and VL from preto post-intervention. DS showed statistically greater increases in the RF at 30% and 50% of muscle
length, whereas no MT differences were detected at 70% muscle length nor at any aspect of the VL.
Both DS and TRAD increased estimated one RM from pre- to post-study (+34.6% versus +32.0%,
respectively) with no between-condition differences noted. Both conditions showed similar increases
in peak torque (DS: +21.7%; TRAD: +22.5%) and average torque (DS: +23.6%; TRAD: +22.5%) from
pre- to post-study. Our findings indicate a potential benefit of the drop-set method for inducing
non-uniform hypertrophic gains in the RF muscle pursuant to leg extension training. The strategy
did not promote an advantage in improving hypertrophy of the VL, nor in strength-related measures,
compared to traditional training
... Evidências têm destacado que o elevado inchaço muscular pode favorecer ganhos hipertrófi cos 12 . De fato, TF que induzem a um elevado estresse metabólico, porém utilizam baixas cargas (25-35 RM) parecem ser, pelo menos para a hipertrofi a, igualmente efetivos quando comparados a treinos com altas cargas (8)(9)(10)(11)(12) 13 . Assim, métodos de TF que induzem um maior volume de trabalho, bem como um maior estresse metabólico seriam potencialmente favoráveis para promover ganhos de força e hipertrofi a muscular. ...
O objetivo deste estudo foi avaliar as respostas agudas neuromusculares e metabólicas do método de treinamento de força (TF) FST-7. Para tal, 10 homens experientes em TF foram submetidos a três protocolos experimentais. 1) FST-7 (sete séries de 10 repetições de extensão isocinética de joelho com 30 s de intervalo entre as séries, incluindo 20 - 25 s de alongamento do quadríceps); 2) Controle (CON, sete séries de 10 repetições de extensão isocinética de joelho com 30 s de intervalo entre as séries, sem alongamento entre as séries); e 3) Tradicional (TRAD, sete séries de 10 repetições de extensão isocinética de joelho com 120 s de intervalo entre as séries, sem alongamento entre as séries). O trabalho total do TRAD (12.160 ± 2.200 J) foi maior (p < 0,05) que o FST-7 (9.361 ± 1.714 J) e CON (10.730 ± 2.360 J), CON também produziu trabalho total maior que FST-7 (p < 0,05). A queda no trabalho entre as séries (índice de fadiga) foi maior (p < 0,05) no FST-7 (38,5 ± 13,4%) em comparação ao CON (29,0 ± 10,9%) e TRAD (12,0 ± 10,4%). A espessura muscular e o lactato sanguíneo aumentaram significativamente (p < 0,05), no entanto sem diferença entre os três protocolos (p>0,05). Estes resultados sugerem que o FST-7 apresenta respostas metabólicas similares aos métodos CON e TRAD, no entanto o estresse mecânico imposto pelos métodos TRAD e CON foram superiores ao FST-7.
... The inter-set rest interval length is known to be an important variable for creating an effective resistance exercise program [17]. Previous studies determined that protocols with short inter-set rest interval, such as with VLRE, may be more useful for enhancing muscle size and strength adaptations induced by long-term resistance exercise than protocols with long inter-set rest interval [55,56]. This positive effect may be due to increased levels of by-products, such as lactate, during an acute bout of this type of protocol [56,57]. ...
Background
The extremely low loads (e.g., <30% of one-repetition maximum) involved in performing resistance exercise are effective in preventing musculoskeletal injury and enhancing exercise adherence in various populations, especially older individuals and patients with chronic diseases. Nevertheless, long-term intervention using this type of protocol is known to have little effects on muscle size and strength adaptations. Despite this knowledge, very low-intensity resistance exercise (VLRE) with slow movement and tonic force generation (ST) significantly increases muscle size and strength. To further explore efficacy of ST-VLRE in the clinical setting, this study examined the effect of ST-VLRE on post-exercise inhibitory control (IC).
Methods
Twenty healthy, young males (age: 21 ± 0 years, body height: 173.4 ± 1.2 cm, body weight: 67.4 ± 2.2 kg) performed both ST-VLRE and normal VLRE in a crossover design. The load for both protocols was set at 30% of one-repetition maximum. Both protocols were programmed with bilateral knee extension for six sets with ten repetitions per set. The ST-VLRE and VLRE were performed with slow (3-sec concentric, 3-sec eccentric, and 1-sec isometric actions with no rest between each repetition) and normal contractile speeds (1-sec concentric and 1-sec eccentric actions and 1-sec rests between each repetition), respectively. IC was assessed using the color-word Stroop task at six time points: baseline, pre-exercise, immediate post-exercise, and every 10 min during the 30-min post-exercise recovery period.
Results
The reverse-Stroop interference score, a parameter of IC, significantly decreased immediately after both ST-VLRE and VLRE compared to that before each exercise (decreasing rate >32 and 25%, respectively, vs. baseline and/or pre-exercise for both protocols; all Ps < 0.05). The improved IC following ST-VLRE, but not following VLRE, remained significant until the 20-min post-exercise recovery period (decreasing rate >48% vs. baseline and pre-exercise; both Ps < 0.001). The degree of post-exercise IC improvements was significantly higher for ST-VLRE than for VLRE (P = 0.010 for condition × time interaction effect).
Conclusions
These findings suggest that ST-VLRE can improve post-exercise IC effectively. Therefore, ST-VLRE may be an effective resistance exercise protocol for improving cognitive function.
... Moreover, the tick subolesin (SUB) has been considered another promising antigen in vaccine formulation (Fig. 1). SUB is an ortholog of insect and vertebrate akirins (AKR) protein, which is involved in geneexpression regulation (Canales et al., 2009;Goto et al., 2004;Vincent-Johnson et al., 1997), and a highly conserved protein involved in modulating feeding and reproduction with a protective effect against all tick developmental stages when used in recombinant protein immunization (Domingos et al., 2013). This protein was silenced by de la Fuente et al. (2006) through RNAi in Dermacentor variabilis, leading to the degeneration of certain tick tissues, such as the guts, salivary glands, reproductive tissues, and embryos. ...
Ticks are considered the most important vectors in veterinary medicine with a profound impact on animal health worldwide, as well as being key vectors of diseases affecting household pets. The leading strategy applied to dog tick control is the continued use of acaricides. However, this approach is not sustainable due to surging tick resistance, growing public concern over pesticide residues in food and in the environment, and the rising costs associated with their development. In contrast, tick vaccines are a cost-effective and environmentally friendly alternative against tick-borne diseases by controlling vector infestations and reducing pathogen transmission. These premises have encouraged researchers to develop an effective vaccine against ticks, with several proteins having been characterized and used in native, synthetic, and recombinant forms as antigens in immunizations. The growing interaction between domestic pets and people underscores the importance of developing new tick control measures that require effective screening platforms applied to vaccine development. However, as reviewed in this paper, very little progress has been made in controlling ectoparasite infestations in pets using the vaccine approach. The control of tick infestations and pathogen transmission could be obtained through immunization programs aimed at reducing the tick population and interfering in the pathogenic transmission that affects human and animal health on a global scale.
... Some studies have observed greater increase in muscle size by performing a specialized technique, although, for this condition, training volume was higher too. Of note, Goto et al. [15] showed that carrying out an additional drop-set to failure after five highload sets resulted in a significant increase in the muscle cross-sectional area as opposed to the traditional RT protocol in trained men. Similarly, Walker et al. [16] and English et al. [17] observed advantages for the accentuated eccentric overload technique, compared to traditional RT, on improving lean mass in young men. ...
Specialized resistance training techniques (e.g., drop-set, rest-pause) are commonly used by well-trained subjects for maximizing muscle hypertrophy. Most of these techniques were designed to allow a greater training volume (i.e., total repetitions x load), due to the supposition that it elicits greater muscle mass gains. However, many studies that compared the traditional resistance training configuration with specialized techniques seek to equalize the volume between groups, making it difficult to determine the inherent hypertrophic potential of these advanced strategies, as well as, this equalization restricts part of the practical extrapolation on these findings. In this scenario, the objectives of this manuscript were 1) to present the nuance of the evidence that deals with the effectiveness of these specialized resistance training techniques and – primarily – to 2) propose possible ways to explore the hypertrophic potential of such strategies with greater ecological validity without losing the methodological rigor of controlling possible intervening variables; and thus, contributing to increasing the applicability of the findings and improving the effectiveness of hypertrophy-oriented resistance training programs.
... Evidências têm destacado que o elevado inchaço muscular pode favorecer ganhos hipertrófi cos 12 . De fato, TF que induzem a um elevado estresse metabólico, porém utilizam baixas cargas (25-35 RM) parecem ser, pelo menos para a hipertrofi a, igualmente efetivos quando comparados a treinos com altas cargas (8)(9)(10)(11)(12) 13 . Assim, métodos de TF que induzem um maior volume de trabalho, bem como um maior estresse metabólico seriam potencialmente favoráveis para promover ganhos de força e hipertrofi a muscular. ...
O objetivo deste estudo foi avaliar as respostas agudas neuromusculares e metabólicas do método de treinamento de força (TF) FST-7. Para tal, 10 homens experientes em TF foram submetidos a três protocolos experimentais. 1) FST-7 (sete séries de 10 repetições de extensão isocinética de joelho com 30 s de intervalo entre as séries, incluindo 20 - 25 s de alongamento do quadríceps); 2) Controle (CON, sete séries de 10 repetições de extensão isocinética de joelho com 30 s de intervalo entre as séries, sem alongamento entre as séries); e 3) Tradicional (TRAD, sete séries de 10 repetições de extensão isocinética de joelho com 120 s de intervalo entre as séries, sem alongamento entre as séries). O trabalho total do TRAD (12.160 ± 2.200 J) foi maior (p < 0,05) que o FST-7 (9.361 ± 1.714 J) e CON (10.730 ± 2.360 J), CON também produziu trabalho total maior que FST-7 (p < 0,05). A queda no trabalho entre as séries (índice de fadiga) foi maior (p < 0,05) no FST-7 (38,5 ± 13,4%) em comparação ao CON (29,0 ± 10,9%) e TRAD (12,0 ± 10,4%). A espessura muscular e o lactato sanguíneo aumentaram significativamente (p < 0,05), no entanto sem diferença entre os três protocolos (p>0,05). Estes resultados sugerem que o FST-7 apresenta respostas metabólicas similares aos métodos CON e TRAD, no entanto o estresse mecânico imposto pelos métodos TRAD e CON foram superiores ao FST-7.
... Capítulo 2 alta e recuperação alta (3 minutos) e um protocolo combinando de alta e baixa intensidade com intervalo curto (30 segundos). Os resultados demonstraram maiores respostas hormonais agudas no treinamento com intensidade moderada e intervalo curto e maior resposta de hipertrofia no treinamento combinado com intervalo curto (GOTO et al., 2004). ...
Neste livro, veremos diferentes aspectos relacionados à elaboração,
planejamento e prescrição do treinamento resistido. Vale aqui uma nota, as
nomenclaturas de treinamento de força e treinamento resistido normalmente
são usadas para descrever o mesmo tipo de treinamento, ou seja, o treinamento
com pesos, halteres ou máquinas utilizados na busca do aprimoramento muscular
do organismo. Neste livro, iremos nos referir sempre como treinamento resistido,
pois acreditamos que seja uma nomenclatura mais didática e de acordo com a
literatura internacional, sendo que consideraremos o treinamento de força um dos
tipos do treinamento resistido (treinamento de força máxima e/ou explosiva, por
exemplo).
O objetivo maior deste livro é proporcionar a você, acadêmico, conhecimentos
necessários o suficiente para se trabalhar o treinamento resistido com diferentes
populações chamadas de especiais. Populações especiais é um termo utilizado
normalmente para se referir a um grupo de pessoas que necessitam de alguns
cuidados a mais quando estão envolvidos em algum tipo de atividade, no nosso
caso, o treinamento físico. Perpassaremos por conhecimentos aplicados aos
diferentes estágios do ciclo da vida, o treinamento resistido aplicado às mulheres
grávidas, às crianças, aos adolescentes e jovens, aos adultos com ou sem
algum tipo de doença. Nesse ponto, abordaremos a aplicação do treinamento
resistido para portadores de diferentes tipos de doenças não transmissíveis, como
cardiovasculares. Veremos também os conceitos aplicados na população idosa.
No Capítulo 1, o fundamental objetivo será conhecer os principais conceitos
e aspectos relacionados à elaboração e prescrição do treinamento resistido que
causam as adaptações no organismo. No Capítulo 2, o objetivo é identificar os
fatores que influenciam na prescrição do treinamento resistido e compreender
como esses fatores podem ser manipulados em cada tipo de treinamento. Já no
Capítulo 3, o objetivo principal será compreender as diferentes necessidades das
populações especiais e entender as recomendações de prescrição do treinamento
resistido para estes grupos e os benefícios advindos desta prática.
... Thus, several factors should be considered in the translation of general RT research to athletic populations. For example, a number of studies have used machine-based, isolated movement tasks or a single-exercise regime to investigate RT strength adaptations (see Ref. 10,19 for examples). Moreover, while some authors have used periodized programs that may reflect typical PL practice (12,26), these studies along with other more general RT interventions (13,35) are typically 16 weeks or less in duration. ...
Strength is a fundamental component of athletic performance and development. This investigation examined the long-term strength development of powerlifting (PL) athletes. The rate of strength gain/day was assessed in 1897 PL athletes (F = 626, M = 1,271) over a 15-year period (2003–2018). Independent T-tests explored sex differences in baseline absolute (kg) and relative strength (kg·body mass−1 [bm]) recorded from the first competition, and strength gain/day (kg·d−1). Analyses based on initial strength quartiles were conducted using one-way analysis of variances with significance set at p < 0.05. Bivariate correlational analysis tested for relationships between strength gain/day and baseline strength, the number of competitions, and mean days between competitions. Males had greater absolute (M: 513.3 ± 99.8 kg, F: 289.4 ± 55.7 kg, p < 0.001) and relative (M: 5.89 ± 1.04 kg·bm−1, F: 4.27 ± 0.85 kg·bm−1, p < 0.001) strength at baseline. Overall, strength gain/day (F: 0.12 ± 0.69 kg·d−1, M: 0.15 ± 0.44 kg·d−1, p = 0.318) was similar between sexes. However, the strongest males showed a lower rate of strength improvement (0.102 kg·d−1) compared with least strong males (0.211 kg·d−1), p = 0.010. No differences were observed across quartiles for females. Correlational analyses revealed significant but weak negative relationships between strength gain/day and the mean days between competitions for females (r2 = −0.120, p = 0.003) and males (r2 = −0.190, p < 0.001). Similar relationships were observed for baseline strength (r2 = −0.073, p = 0.009) and the number of competitions (r2 = −0.111, p < 0.001) for males. The results suggest similar strength adaptation between sexes. The strongest males improve more slowly, possibly due to a ceiling effect. Collectively, the findings provide novel evidence of real-world long-term strength adaptations that may be particularly useful to understand athlete development, to aid periodized programming, and to benchmark strength over time.
... Nonetheless, it is important to note that the VG performed 45% fewer repetitions than the RMG and obtained similar increases in the total muscular volume of the lower limbs. The greater number of repetitions performed by the RMG during the entire training period resulted in different metabolic and neural stresses, 26 which may have a greater impact on the processes of muscular hypertrophy. ...
This study examines the effects of two strength training (ST) programs, one based on mean propulsive velocity (MPV) and another under the traditional method, the % one-repetition maximum (1RM), on neuromuscular performance and muscle composition in girls who play soccer. Fifty players with an average age of 13.6 ± 1.2 years participated in the study and were randomly assigned into three groups: a maximal execution velocity training group (VG, n = 15), a maximal strength group (RMG, n = 13), and a control group (CG, n = 18). The study was developed for a period of twelve weeks during regular team training to prepare for the season. The VG and RMG groups performed additional strength or muscle power training three times a week, including movements of full squat and pedaling on a cycle ergometer. The two types of training groups and the control group exhibited significant gains. However, the greatest increases were achieved with VG training, with significant increases (p < 0.000) in maximal strength, (p < 0.000) squat power, (p < 0.000) velocity over 30 m, (p < 0.000) cycle ergometer power, and (p < 0.008) lower limb muscle mass. Statistically significant differences were observed between VG and RMG in countermovement jump (CMJ) (p < 0.008) and squat power (p < 0.01) tests, between VG and CG in CMJ (p < 0.01), squat power (p < 0.000), and maximal squat strength (p < 0.000), and between RMG and CG in maximal squat strength (p < 0.000) only. These findings might indicate that high-velocity ST can be performed simultaneously with regular training to improve the explosive actions of soccer players.
... The results show conflicting evidence on whether shorter rest periods generate greater anabolic hormonal responses versus longer rest periods. Goto et al. (2004) examined growth hormone responses with varying rest periods, as well as chronic adaptations to hypertrophy-and strength-oriented programs. All subjects were recreationally trained, but they had not participated in a regular training program for at least 6 months prior to commencement of the study. ...
The purpose of this study was to compare the effects of 1-minute versus 3-minute, between-set rest intervals on muscular hypertrophy adaptations in 12 recreationally, resistance-trained males, 18-25 years of age over a 6-week period. Week 1 consisted of dual-energy X-ray absorptiometry (DEXA) scans, and 1-repetition maximum (1RM) testing in the back squat and bench press. Weeks 2 through 5 consisted of four resistance training sessions per week, split between two lower-body and two upper-body workouts. The resistance training protocol started at 3 sets of 10 repetitions at 67% of 1RM and progressed from there. Week 6 consisted of follow-up body composition assessment, using DEXA scan, and 1RM testing of back squat and bench press. The findings of the study revealed no significant differences between the effects of 1-minute and 3-minute rest periods on muscle hypertrophy in recreationally strength-trained males during a 4-week training program.
... Pembolehubah latihan merujuk kepada parameter atau perkara-perkara yang boleh diukur dan diubahsuai bagi memberikan respon dan kesan adaptasi yang diperlukan bagi setiap program latihan yang dibina (Goto et al., 2004;Toigo & Boutellier, 2006). Terdapat lebih daripada 50 pembolehubah latihan secara umumnya yang boleh dimanupulasi dalam pembinaan program latihan bagi menghasilkan kesan latihan yang berbeza-beza mengikut objektif yang ditetapkan (Figueiredo, de Salles, & Trajano, 2018;Kraemer et al., 2002;Mohamad, Nosaka, & Cronin, 2011;Suchomel, Nimphius, Bellon, & Stone, 2018;Tan, 1999). ...
OBJEKTIF PEMBELAJARAN:
1. Megenalpasti dan memahami komponen kecergasan fizikal, prinsipprinsip latihan, dan pembolehubah-pembolehubah latihan.
2. Memahami perkaitan antara komponen kecergasan, prinsip-prinsip latihan
dan pembolehubah-pembolehubah latihan dengan tindakbalas sistem
tenaga, otot dan rangka.
KATA KUNCI:
komponen kecergasan berteraskan
kesihatan
komponen kecergasan berteraskan lakuan
motor
daya tahan kardiovaskular
daya tahan otot
kekuatan otot
kelenturan
komposisi tubuh badan
imbangan
koordinasi
kuasa
kelajuan
ketangkasan
masa reaksi
prinsip lebihan bebanan
prinsip ansur maju
prinsip kebolehbalikan
prinsip pengkhususan
prinsip pemulihan
kontinum sistem tenaga
... Participants then completed each session in a counterbalanced order. Breaks between each cycling session were approximately 10 min in duration and allowed for participants' blood pressure and heart rate to return to baseline levels-as suggested in other exercise literature [36]. During these between-session breaks, participants were asked to complete the SM survey. ...
The development of innovative technology, such as virtual reality (VR), has provided opportunities for promoting physical activity (PA) in a fun and engaging manner. The purpose of this study was to examine differences in young adults' situational motivation (SM) among immersive VR, non-immersive VR, and traditional stationary cycling sessions. In all, 49 healthy college students (35 females; M
age
= 23.6 years, SD = 3.4; M%BF = 24.0%, SD = 7.5) completed three separate 20 min cycling sessions: (1) immersive VR cycling; (2) non-immersive VR cycling; and (3) traditional cycling. Participants' SM was assessed via the situational motivation scale, which included four subconstructs: intrinsic motivation, identified regulation, external regulation, and amotivation. Repeated measures ANOVAs indicated significant differences for situational motivation between cycling sessions (F (2, 96) = 4.74-53.04, p < 0.01, ηp2 = 0.090-0.525). Specifically, participants elicited the highest level of intrinsic motivation in immersive VR cycling compared to the other two sessions. Moreover, participants in both immersive VR and traditional cycling showed greater identified regulation than the non-immersive VR session. Furthermore, participants showed greater external regulation compared to the immersive VR session. In addition, greater amotivation was observed in non-immersive VR compared to the immersive VR session. Findings suggested that immersive VR exercise has the potential to be an attractive exercise alternative, possibly promoting greater PA participation and adherence among young adults.
... According to numerous authors the rest interval in resistance training has a significant impact on acute and chronic metabolic, endocrine and cardiovascular responses and adaptive changes. [17][18][19] Reviews by Rhea et al. 20 and Freitas de Salles et al. 4 have revealed that for maximal strength and hypertrophy multiple sets per muscle group are superior to single sets. However, this superiority depends on the ability to sustain consistent repetitions over consecutive sets of the exercise. ...
BACKGROUND: The resistance training variables which significantly affect the range of adaptive changes include the rest interval (RI) and volume of total lifted load. The length of the rest interval is highly dependent on the training objective, training status and exercise volume. Therefore the main objective of the research was the evaluation of 3 different rest intervals (2, 4, and 6 min) on total volume load in a 10 set training session of the bench press (BP) exercise performed with a load of 60%1RM to concentric failure.
METHODS: Ten male athletes (age, 32±4.6 years, body mass 86.3±5.2 kg, body height 181.3±4.2 cm) performed 10 sets of the BP with a load of 60% 1RM until concentric failure on 3 occasions, with 2-, 4- and 6-minute rest intervals. Capillary blood samples were taken for the analysis of lactate concentration (LA) and blood pH. The samples were taken at rest, and approximately one minute after the cessation of the 3rd, 6th and 10th set.
RESULTS: Using shorter RI (2 min) in multiple sets performed to concentric muscular failure highly stressed the glycolytic system, which is evidenced by highest post exercise LA and significantly lowered blood pH (P<0.001). This may be beneficial for the development of local muscular endurance. On the other hand, longer (6 min) RI may create conditions for a higher volume of total workload and adaptive changes directed at strength and hypertrophy.
CONCLUSIONS: The rest intervals of 4 and 6 minutes allow lifting of high loads without significant metabolic acidosis in the last sets, therefore useful for the development of maximum strength and hypertrophy. The rest interval of 2 minutes decreases the training workload with higher LA in the last sets of the BP exercise, therefore this rest interval can stimulate strength endurance and glycolytic metabolism.
... We randomly assigned subjects to undergo 2 separate 20-minute exergaming sessions during a single laboratory visit: (a) Xbox 360 Reflex Ridge -single player and (b) Xbox 360 Reflex Ridge -double player. To limit any potential carryover effect, we randomized subjects in a counterbalanced order and provided 10 minutes of complete rest to subjects between exercise sessions to allow blood pressure, HR, and RPE to return to approximately baseline levels before the next exercise session (24). ...
McDonough, DJ, Pope, ZC, Zeng, N, Lee, JE, and Gao, Z. Retired elite athletes' physical activity, physiological, and psychosocial outcomes during single- and double-player exergaming. J Strength Cond Res XX(X): 000-000, 2019-Elite athletes (i.e., athletes who play sport professionally) are a population who commonly exceed recommended physical activity (PA) guidelines and have higher health statuses compared with the general population. However, elite athletes transitioning into retirement often become physically inactive given they no longer require long hours of training and competition, and their physiological and psychosocial health suffers as a result. Therefore, this study's purpose was to examine differences in retired elite athletes' acute PA, physiological, and psychosocial outcomes during single- and double-player exergaming. Twenty retired Olympic athletes (18 females; X[Combining Overline]age = 27.3 ± 4.3 years) participated in 2 separate 20-minute exergaming sessions (a): Xbox 360 Reflex Ridge single player and (b) Xbox 360 Reflex Ridge double player. Subjects' situational interest, enjoyment, and self-efficacy were examined using validated questionnaires; rating of perceived exertion (RPE) using the modified Borg RPE scale; and moderate-to-vigorous PA, steps, and energy expenditure tracked using ActiGraph GT3X+ accelerometers. Repeated-measures analysis of variances revealed no significant differences for any outcome between the 2 exercise sessions except for RPE (F (1, 38) = 4.6; p < 0.05; η = 0.11), which was higher in the single-player session compared with the double-player session (10.3 ± 2.3; 8.7 ± 1.6, respectively). Observations indicated double-player exergaming to be perceived as less intense than single-player exergaming despite similar PA and physiological outcomes, suggesting retired elite athletes may better adhere to exergaming in a double-player mode.
... Each RT system manipulates a specific set of RT variables (e.g., intensity, volume, muscle action, type and order of exercises, repetition velocity) [6], which emphasizes distinct physiologic mechanisms to enhance RT-induced adaptations [7]. Although some acute studies have showed greater muscle activation [8,9] or metabolic stress [10] for RT systems when compared to traditional RT (TRAD; i.e. sets with constant number of repetitions and load), RT systems' ability to enhance chronic adaptations are equivocal. Accordingly, it has been suggested that increases in muscle strength and hypertrophy are greater for RT systems [3,[11][12][13][14], while others reported either similar neuromuscular adaptations [4,6] or greater gains [15,16] for TRAD. ...
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.
... This novel finding suggests that the volume of muscle mass activated is a key factor in the endocrine portion of the anabolic response to RT. Indeed, RT studies that have examined volume of training report lower volumes produce a lesser endocrine response of anabolic hormones such as growth hormone and testosterone (Goto et al. 2004;Gotshalk et al. 1997). In contrast to these results and the findings we report here, Walker et al. (2004) did not show a difference in plasma myostatin response between a whole body and a UB training protocol like our own, when semi-quantitatively examined by Western blot. ...
Purpose
Due to the mechanistic role of myostatin and follistatin in modulating muscle mass, shifts in the follistatin to myostatin ratio (F:M) may help explain changes in muscular size in response to resistance training (RT). The present study examined whether differential responses in follistatin and myostatin occur based on the amount of active musculature in a RT program in middle-aged men.
Methods
Forty middle-aged men (age = 46.5 ± 3.1 years) were randomly assigned to 1 of 4 groups, upper-body RT (UB; n = 10), lower-body RT (LB; n = 10), combined RT (UB + LB; n = 10) or control (C; n = 10). The training protocol consisted of three exercise sessions per week for 8 weeks. Blood samples were obtained at baseline and 48 h after the final session of the training program.
Results
Muscle mass significantly increased (p < 0.05) following UB = 0.76 ± 0.46 kg, LB = 0.90 ± 0.29 kg, UB + LB = 1.38 ± 0.70 kg, compared to no changes after control. Serum follistatin increased in the LB = 0.24 ± 0.06 ng mL⁻¹, UB = 0.27 ± 0.17 ng mL⁻¹, UB + LB = 0.50 ± 0.18 ng mL⁻¹, while serum myostatin decreased in the LB = − 0.11 ± 0.08 ng mL⁻¹ and UB + LB = − 0.34 ± 0.23 ng mL⁻¹, but not UB = 0.07 ± 0.16 ng mL⁻¹. Further, change in concentration following training was larger between UB + LB and either LB or UB alone for both follistatin and myostatin.
Conclusions
Both UB and LB increase muscle mass and alter the F: M ratio; however, the change in these endocrine markers is approximately twice as large if UB and LB is combined. The endocrine response to RT of myostatin and follistatin may depend on the volume of muscle mass activated during training.
... Nonetheless, it is important to note that the VG performed 45% fewer repetitions than the RMG and obtained similar increases in the total muscular volume of the lower limbs. The greater number of repetitions performed by the RMG during the entire training period resulted in different metabolic and neural stresses, 26 which may have a greater impact on the processes of muscular hypertrophy. ...
The objective of this study was to characterize and compare the maximum and fast strenght, anaerobic power, speed of execution and displacement according to the playing position in 59 young players divided into two categories. The methodology consisted of an assessment of body mass, height and 4 tests, explosive force (CMJ and SJ), velocity (30 m), anaerobic power (Wingate test) and maximum force (% 1RM). The results showed the under 15 years old with the best records on most variables except for the size and mean propulsive velocity (MPV) squat. In the maximum power test pre-juvenile goalkeepers and defences line obtained the best record (409.11 W ± 86.73 W) and 1RM (60.58 kg ± 13.69 Kg) without significant differences. Finally, we found a significant interaction between the position and the game category in MPV squat, F55 = 21.41; P = 0.021, eta square = 0.093 among the players of the two categories studied. © 2019, Universidad Autonoma de Madrid y CV Ciencias del Deporte. All rights reserved.
... Pembolehubah latihan merujuk kepada parameter atau perkara-perkara yang boleh diukur dan diubahsuai bagi memberikan respon dan kesan adaptasi yang diperlukan bagi setiap program latihan yang dibina (Goto et al., 2004;Toigo & Boutellier, 2006). Terdapat lebih daripada 50 pembolehubah latihan secara umumnya yang boleh dimanupulasi dalam pembinaan program latihan bagi menghasilkan kesan latihan yang berbeza-beza mengikut objektif yang ditetapkan (Figueiredo, de Salles, & Trajano, 2018;Kraemer et al., 2002;Mohamad, Nosaka, & Cronin, 2011;Suchomel, Nimphius, Bellon, & Stone, 2018;. ...
Bab asas anatomi dan fisiologi manusia ini menyediakan informasi mengenai:
1. Unit asas tubuh dan bagaimana unit asas tersebut menjadikan organisma
berfungsi.
2. Komponen dan fungsi sistem integumen serta penyakit yang berkaitan.
3. Fungsi, pengkelasan serta penyakit berkaitan tulang dan sendi.
4. Jenis otot, faktor dan proses pertumbuhan otot, serta penyakit otot.
5. Komponen sistem saraf, penginsyaratan sel saraf dan penyakit saraf.
6. Kelenjar hormon, jenis dan fungsi hormon, dan penyakit berkaitan
hormon.
7. Struktur dan fungsi sistem pernafasan, proses pernafasan dan faktor
kawalan pernafasan, pengaruh tekanan terhadap pernafasan dan penyakit
yang berkaitan.
8. Komponen sistem kardiovaskular, fungsi jantung dan darah, dan penyakit
berkaitan jantung dan darah.
9. Jenis keimunan, sel-sel imun berserta fungsi, tindak balas imun terhadap
patogen dan penyakit berkaitan sostem imun.
... In the present study, muscle thickness of the BB long head, used as an index of muscle hypertrophy, increased significantly in both groups after 12-weeks of strength training, but to a greater extent for the 3/7 method than the 8 × 6 method (9.6 vs. 5.5%; p < 0.01). These results are in agreement with the hypothesis that brief rest interval between sets might provide a superior stimulus for muscle hypertrophy than longer rest period (Kraemer et al. 1990;Goto et al. 2004;Bottaro et al. 2009;de Salles et al. 2009;Henselmans and Schoenfeld 2014). More recently, several papers have shown that small loads (20-40% of 1RM), mobilized under blood flow restriction, may also induce an increase in muscle mass and maximal strength (Takarada et al. 2002;Wernbom et al. 2008;Manini and Clark 2009;Dankel et al. 2017). ...
Aim
This study investigated the efficacy of a new strength training method on strength gain, hypertrophy, and neuromuscular fatigability.
Methods
The training exercise consisted of elbow flexion against a load of ~ 70% of one repetition maximal (1RM). A new method (3/7 method) consisting of five sets of an increasing number of repetitions (3 to 7) during successive sets and brief inter-set intervals (15 s) was repeated two times after 150 s of recovery and compared to a method consisting of eight sets of six repetitions with an inter-set interval of 150 s (8 × 6 method). Subjects trained two times per week during 12 weeks. Strength gain [1RM load and maximal isometric voluntary contraction (MVC)], EMG activity of biceps brachii and brachioradialis, as well as biceps’ brachii thickness were measured. Change in neuromuscular fatigability was assessed as the maximal number of repetitions performed at 70% of 1RM before and after training.
Results
Both 3/7 and 8 × 6 methods increased 1RM load (22.2 ± 7.4 and 12.1 ± 6.6%, respectively; p < 0.05) and MVC force (15.7 ± 8.2 and 9.5 ± 9.5%; p < 0.05) with a greater 1RM gain (p < 0.05) for the 3/7 method. Normalized (%Mmax) EMG activity of elbow flexors increased (p < 0.05) similarly (14.5 ± 23.2 vs. 8.1 ± 20.5%; p > 0.05) after both methods but biceps’ brachii thickness increased to a greater extent (9.6 ± 3.6 vs. 5.5 ± 3.7%; p < 0.05) for the 3/7 method. Despite subjects performing more repetitions with the same absolute load after training, neuromuscular fatigability increased (p < 0.05) after the two training methods.
Conclusion
The 3/7 method provides a better stimulus for strength gain and muscle hypertrophy than the 8 × 6 method.
... Therefore, football requires good technical and tactical training, as well as a high physical training (Marinău, 2017). The rational dosage of the effort under supervision can ensure the success of this training (Goto, 2004). It is more than just a ball game; it is the sportive discipline that is most widely spread in most countries around the world. ...
This study was designed to determine the evolution of the physical training level of the "CSL SPORTING LUGAȘ" female football during the competitive year 2017-2018 by conducting two tests before and after the physical training program, and using Gacon and Yo-Yo tests. These tests are an element of novelty in Romanian football overall and in female football especially, as they introduce a certain level of competition, generating emulation and desire to compete. These tests have a high degree of difficulty. In this regard, we can also highlight athletes`athletes`desire to complete the tests with best results.
... Conversely, greater precision in programming characteristics (i.e., intensity, volume, density) is needed for initiating this process in trained adults [5,8]. For these individuals, set frequency [20], training intensity and volume [21,22] and rest intervals [23] have all been found to influence the hypertrophy response. However, in several cases, the observed hypertrophy was not consistent across each site [21][22][23], nor were these differences compared. ...
Resistance training may differentially affect morphological adaptations along the length of uni-articular and bi-articular muscles. The purpose of this study was to compare changes in muscle morphology along the length of the rectus femoris (RF) and vastus lateralis (VL) in response to resistance training. Following a 2-wk preparatory phase, 15 resistance-trained men (24.0 ± 3.0 y, 90.0 ± 13.8 kg, 174.9 ± 20.7 cm) completed pre-training (PRE) assessments of muscle thickness (MT), pennation angle (PA), cross-sectional area (CSA), and echo-intensity in the RF and VL at 30, 50, and 70% of each muscle’s length; fascicle length (FL) was estimated from respective measurements of MT and PA within each muscle and region. Participants then began a high intensity, low volume (4 x 3–5 repetitions, 3min rest) lower-body resistance training program, and repeated all PRE-assessments after 8 weeks (2 d ∙ wk⁻¹) of training (POST). Although three-way (muscle [RF, VL] x region [30, 50, 70%] x time [PRE, POST]) repeated measures analysis of variance did not reveal significant interactions for any assessment of morphology, significant simple (muscle x time) effects were observed for CSA (p = 0.002) and FL (p = 0.016). Specifically, average CSA changes favored the VL (2.96 ± 0.69 cm², p < 0.001) over the RF (0.59 ± 0.20 cm², p = 0.011), while significant decreases in average FL were noted for the RF (–1.03 ± 0.30 cm, p = 0.004) but not the VL (–0.05 ± 0.36 cm, p = 0.901). No other significant differences were observed. The findings of this study demonstrate the occurrence of non-homogenous adaptations in RF and VL muscle size and architecture following 8 weeks of high-intensity resistance training in resistance-trained men. However, training does not appear to influence region-specific adaptations in either muscle.
... Harris et al. were among the first to demonstrate that oral elevated intramuscular PCr may promote buffering of H + ions and ADP during maximal muscular contractions and reduce neuromuscular fatigue, this may allow for an increase in the number of muscular contractions possible during a given short-bout high intensity activity, such as resistance training.18,19,25,26,[49][50][51] This ability for prolonged muscle contractions may ultimately lead to hypertrophy of the targeted skeletal muscle tissue and increased lean body mass due to the increased resistance training volume and elevated muscle protein synthesis.23,47,[52][53][54][55] Phillips and colleagues propose that because one of the most crucial stimuli for elevating skeletal muscle protein synthesis is muscle contraction, the greater number of contractions in a given training period may promote an elevatedBody Mass and Lean Mass Effects of CrH2O SupplementationThough most of the literature has found acute CrH2O interventions to positively influence body composition, few studies have found no or insignificant (~0.5 kg) changes anabolic effect of Cr on skeletal muscle tissue synthesis, or other indirect factors.64 ...
... 3minutes) might be more advantageous than a moderate intensity, high-volume and short rest (i.e. 1 min) for stimulating upper-body strength gains and muscle hypertrophy in resistance-trained men (Magine et al., 2015). Additionally, specific manipulations on high-intensity strength exercise with low intensities to the concentric failure can be also advantageous to strength and hypertrophy (Goto et al., 2004). These results support the implementation of a systematically varied design to optimize the RE outcomes. ...
The aim of this study was to investigate the impact of different periodization models on strength and local muscle endurance. Twenty trained men (25.45 ± 2.984 years, 75.34 ± 6.05 kg, 177.25 ± 4.92 cm, 23.96 ± 1.64 kg . m-2) were randomly assigned in two groups: undulling periodization (UPG) and traditional periodization group (TPG), respectively. All the subjects performed one repetition maximum (1-RM) strength test and a local muscle endurance test (60% of 1-RM to failure) before, during and after experimental period. The UPG executed 30 workout sessions with daily modifications regarding intensity, volume and rest period length. The TGP was divided into 3 phases (10 workout sessions in each phase) with the same changes executed by the other group in distinct methodological variables (intensity, volume and rest period length). After the ANCOVA analysis, no significant differences were found in both maximum strength attempts, bench press (p = 0.878) and triceps pull-down (p = 0.967). The same results occurred for local muscular endurance on the bench press (p = 0.777) or triceps pull-down (p = 0.494). However, the effect size presented moderate post-test strength gains (ESs = 0,352) and local muscular endurance (ESs = 0.367). Our results indicated that daily undulling periodization seems to be more influent in increasing muscular strength and local muscular endurance according to effect size evidence.
... Jones et al. (11) related to sarcopenia with two factors: decreased protein synthesis due to a decrease in production and secretion of hormones such as GH and testosterone in aging, as well as an increase in protein degradation through sedentarism and increased MSTN. Goto et al. (7), on the other hand, demonstrated that resistance training increases muscle mass. ...
Marine DA, Fabrizzi F, Nonaka KO, Duarte ACGO, Leal AMO. Myostatin and Follistatin mRNA Expression in Castrated Rats Submitted to Resistance Training. JEPonline 2018;21(1):162-171. The purpose this study was to evaluate the influence of resistance training on the expression of myostatin and follistatin in castrated rats. Wistar rats were placed under controlled conditions divided into four groups: (a) castrated trained; (b) intact trained; (c) castrated sedentary; and (d) intact sedentary. The animals trained for 8 wks, climbing a ladder with weights tied to their tail. Myostatin (MSTN) and follistatin (FS) mRNA were quantified by qRT-PCR of the white gastrocnemius and P≤0.05 were considered statistically significant. MSTN mRNA expression was higher in the castrated sedentary than the intact sedentary, the intact trained, and the castrated trained. The expression of FS mRNA decreased in the castrated trained compared to the intact sedentary and the intact trained. MSTN expression increased in the skeletal muscle of castrated rats due to the absence of testosterone and the influence of training that promoted regulation in relation to the castrated sedentary. The FS decreased with castration and training with difference of trained castrated and intact trained, and sedentary intact, and there may be influence of other hormones in the absence of testosterone. Resistance training was able to regulate the expression of MSTN in the castrated group, and reduced the FS gene expression in the same group. The castration increased the expression of MSTN in castrated sedentary rats.
Abstract: The Fascia Stretch Training 7 Sets (FST-7) method has gained popularity in the recent years being disseminated by American bodybuilders. The purpose of the study was to compare the effects of the Fascia Stretch Training 7 Sets (FST-7) method with or without passive stretching between sets on metabolic variables (lactate [LAC] and creatine kinase [CK]), performance (total training volume - TTV) and rating of perceived exertion (RPE) in trained men. For this, nine recreationally trained men (23.2 ± 1.7 years; 174.2 ± 6.2 cm; 84.6 ± 9.8 kg, 3.4 ± 1.0 years of experience in strength training) were submitted to the test and re-test of 10 repetition maximum (10RM) in the barbell bench press and fly with dumbbells on different days, respecting a 48-hour interval between the test and re-test sessions. After 72 hours of the last test day, participants performed the experimental protocols in randomized order with a 72-hour interval between sessions. Blood samples were taken 10 minutes before and immediately after the training protocols. The protocol without stretching was significantly increased LAC concentrations (p = 0.029). However, the same did not occur for the concentration of CK (p = 0.302). The TTV was higher for the protocol without stretching (p < 0.001), and the RPE was significantly higher for the protocol with stretching between sets (p = 0.003). We concluded that the FST-7 method with stretching resulted in higher RPE, which may be related to the decline in performance, translated by the lower TTV in relation to the condition without stretching. This lower TTV may have affected the lower LAC accumulation observed in the FST-7 method with stretching.
Hypertrophy can be operationally defined as an increase in the axial cross-sectional area of a muscle fiber or whole muscle, and is due to increases in the size of pre-existing muscle fibers. Hypertrophy is a desired outcome in many sports. For some athletes, muscular bulk and, conceivably, the accompanying increase in strength/power, are desirable attributes for optimal performance. Moreover, bodybuilders and other physique athletes are judged in part on their muscular size, with placings predicated on the overall magnitude of lean mass. In some cases, even relatively small improvements in hypertrophy might be the difference between winning and losing in competition for these athletes. This position stand of leading experts in the field synthesizes the current body of research to provide guidelines for maximizing skeletal muscle hypertrophy in an athletic population. The recommendations represent a consensus of a consortium of experts in the field, based on the best available current evidence. Specific sections of the paper are devoted to elucidating the constructs of hypertrophy, reconciliation of acute vs long-term evidence, and the relationship between strength and hypertrophy to provide context to our recommendations.
Une nouvelle méthode de musculation, appelée méthode 3/7, consistant à réaliser 5 séries en escalier (de 3 à 7 répétitions) avec une charge de 70 % d’une répétition maximale (1RM) espacées d’un temps de récupération court (15 secondes) s’avère plus efficace pour augmenter la force musculaire qu’une méthode classique (à nombre de répétitions constant) avec un temps de récupération long (150 secondes ; Laurent et coll., 2016). L’intérêt de cette méthode est de combiner l’utilisation de charges modérées tout en induisant une réponse métabolique importante (Penzer et coll., 2016). Au regard du gain de temps que procure cette méthode, elle pourrait être intégrée dans la préparation physique de sportifs, mais également de personnes prises en charge dans le cadre d’une revalidation.Dès lors, l’objectif général de ce travail de thèse a été d’étudier l’efficacité de la méthode 3/7 sur les gains de force et sur les adaptations musculaires et plus spécifiquement de mieux comprendre les facteurs responsables de celle-ci. A cet effet, trois principaux projets ont été élaborés. Le premier avait pour objectif d’optimiser l’efficacité de la méthode 3/7 en investiguant les gains de force maximale, ainsi que les adaptations neurophysiologiques et musculaires sous-jacentes suite à 12 semaines d’entrainement des muscles fléchisseurs du coude. Lors du deuxième projet, l’effet aigu de la méthode 3/7 sur les dommages musculaires, les réponses inflammatoires, hormonales, et métaboliques y compris celles sur le stress oxydant a été évalué à la suite d’une séance de renforcement musculaire composée de quatre exercices (le développé couché, l’extension de jambes à la presse inclinée, le tirage horizontal et la flexion plantaire). Enfin, le troisième projet a permis de suivre l’évolution des réponses biochimiques aigües, des adaptations musculaires et des adaptations nerveuses, ainsi que de la force suite à cette méthode au cours de 22 séances d’entrainement composées des mêmes exercices que ceux du projet 2. Lors de nos 3 projets, la méthode 3/7 a toujours été comparée à une méthode dite classique à charge constante et de volume de travail total similaire mais avec une récupération plus longue (méthode 8x6).Les gains de force maximale ont été déterminés par des contractions volontaires maximales isométriques (CVMI) et la charge maximale mobilisée, lors de 1RM ou de 3RM. L’évolution des paramètres neurophysiologiques a principalement été étudiée par l’activité électromyographique (EMG), l’onde motrice maximale (Mmax) ainsi que le niveau d’activation volontaire maximale (AV). Pour les paramètres biochimiques, nous avons réalisé des analyses des marqueurs sanguins du stress oxydant, du stress métabolique, des dommages musculaires, de la réponse inflammatoire et de la réponse hormonale. Enfin, pour les paramètres musculaires, des mesures échographiques ont été effectuées, et l’évaluation de la masse maigre et de la masse grasse a été déterminée par absorption bi-photonique à rayons X. De plus, le niveau d’oxygénation tissulaire a été mesuré via spectrométrie proche de l’infrarouge.La méthode 3/7 a induit un déficit d’oxygénation plus important que la méthode 8x6 (Projet 1) entrainant une augmentation de lactate et de testostérone dans le sang immédiatement après la séance tandis que les témoins des dommages musculaires (créatine kinase et myoglobine) ont augmenté de manière similaire suite aux 2 méthodes (Projet 2 et 3). Le lactate agirait sur la production d’espèces oxygénées activées (EOA), d’interleukine-6, de cortisol et de l’hormone de croissance qui induiraient à leur tour une augmentation des leucocytes (Projets 2 et 3). La méthode 3/7 a amélioré l’AV sans différence avec la méthode 8x6 (Projet 3) mais a aussi entrainé des adaptations musculaires et amélioré la force maximale (Projet 1 et 3) même si cette méthode n’est pas systématiquement plus efficace que la méthode 8x6 (Projet 3). Il est également à noter que la capacité du sujet à pouvoir réaliser seul le volume de travail imposé par la méthode 3/7 influencerait les adaptations à l’entrainement (Projet 3).Il convient de souligner que l’évolution des paramètres biochimiques n’implique pas une relation directe de cause à effet sur les adaptations musculaires. De plus, le stress métabolique lors de la méthode 3/7 ne semble pas induire systématiquement un effet supplémentaire à la signalisation intramusculaire d’origine mécanique. La synthèse protéique myofibrillaire pourrait atteindre un niveau de saturation de la réponse anabolique suite à la signalisation intramusculaire d’origine mécanique. D’autre part, les divergences des résultats entre nos différents projets pourraient provenir des variabilités inter-individuelles. Les facteurs individuels intrinsèques seraient des déterminants plus importants pour développer la masse musculaire que les paramètres extrinsèques d’un programme d’entrainement. En conclusion, la méthode 3/7 induit des adaptations similaires ou plus importantes qu’une méthode classique (méthode 8x6) mais avec une durée d’entrainement 3 à 4 fois moindre.
Resistance training may differentially affect morphological adaptations along the length of uni-articular and bi-articular muscles. The purpose of this study was to compare changes in muscle morphology along the length of the rectus femoris (RF) and vastus lateralis (VL) in response to resistance training. Following a 2-wk preparatory phase, 15 resistance-trained men (24.0 ± 3.0 y, 90.0 ± 13.8 kg, 174.9 ± 20.7 cm) completed pre-training (PRE) assessments of muscle thickness (MT), pennation angle (PA), cross-sectional area (CSA), and echo-intensity in the RF and VL at 30, 50, and 70% of each muscle's length; fascicle length (FL) was estimated from respective measurements of MT and PA within each muscle and region. Participants then began a high intensity, low volume (4 x 3 - 5 repetitions, 3min rest) lower-body resistance training program, and repeated all PRE-assessments after 8 weeks (2 d ? wk-1) of training (POST). Although three-way (muscle [RF, VL] x region [30, 50, 70%] x time [PRE, POST]) repeated measures analysis of variance did not reveal significant interactions for any assessment of morphology, significant simple (muscle x time) effects were observed for CSA (p = 0.002) and FL (p = 0.016). Specifically, average CSA changes favored the VL (2.96 ± 0.69 cm2, p
This is the extended version of the article presented at the 3rd International Rock Climbing Research Congress, hosted in Telluride, USA fro 5th-7th August 2016 with the title: "Comparison of the Effects of Three Hangboard Training Programs on Maximal Finger Strength in Rock Climbers."
The online version can be found on: https://en-eva-lopez.blogspot.com.es/2018/03/maximal-hangs-intermittent-hangs.html
Introduction:
Muscle force production is usually impaired in people with spinal cord injury (SCI). The use of high-intensity neuromuscular electrical stimulation (NMES) strength training can help promote metabolically active lean muscle mass and thus, increase muscle mass and improve physical health and quality of life (QoL). Nonetheless, NMES is usually used at low-stimulation intensities and there is limited evidence on the effects of high-intensity NMES strength training into improving muscle force and mass, symptoms of spasticity or physical health and quality of life (QoL) in people with SCI.
Methods:
Five individuals with chronic SCI completed five 10-repetition sets of high-intensity knee extension NMES strength training sessions for 12 weeks in both quadriceps muscles. Quadriceps femoris (QF) knee extensor torque was measured on a dynamometer and cross-sectional area (CSAQF) was measured with extended-field-of-view ultrasonography. Venous blood samples were collected for blood lipid profiling and c-reactive protein (CRP) analyses. The Spinal Cord Injury Spasticity Evaluation Tool (SCI-SET) was used to assess symptoms of spasticity and the quality of life index (QLI) SCI version III was used for QoL measures.
Results:
QF tetanic knee extensor torque increased on average by 35% (2 - 92%) and CSAQF increased by 47% (14 - 145%). A significant increase in the HDL/LDL cholesterol ratio (p < 0.001), a mean significant improvement of 4.8% ± 2.3% (absolute value = 0.26) in SCI-SET score was observed, whilst QoL showed a near-significant improvement in the health & functioning domain (15.0 ± 4.2; 17.3 ± 5.1; p = 0.07).
Conclusions:
High-intensity NMES-strength training in people with SCI may improve muscle strength, mass, physical health and QoL. However, replication of these results is necessary before clinical implementation.
Effects of strength training (ST) for 21 wk were examined in 10 older women (64 ± 3 yr). Electromyogram, maximal isometric force, one-repetition maximum strength, and rate of force development of the leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris (QF) and of vastus lateralis (VL), medialis (VM), intermedius (VI) and rectus femoris (RF) throughout the lengths of 3/12–12/15 (Lf) of the femur, muscle fiber proportion and areas of types I, IIa, and IIb of the VL were evaluated. Serum hormone concentrations of testosterone, growth hormone (GH), cortisol, and IGF-I were analyzed for the resting, preexercise, and postexercise conditions. After the 21-wk ST, maximal force increased by 37% ( P < 0.001) and 1-RM by 29% ( P < 0.001), accompanied by an increase ( P < 0.01) in rate of force development. The integrated electromyograms of the vastus muscles increased ( P < 0.05). The CSA of the total QF increased ( P < 0.05) throughout the length of the femur by 5–9%. The increases were significant ( P< 0.05) at 7/15–12/15 Lf for VL and at 3/15–8/15 Lf for VM, at 5/15–9/15 for VI and at 9/15 ( P < 0.05) for RF. The fiber areas of type I ( P < 0.05), IIa ( P < 0.001), and IIb ( P < 0.001) increased by 22–36%. No changes occurred during ST in serum basal concentrations of the hormones examined, but the level of testosterone correlated with the changes in the CSA of the QF ( r = 0.64, P < 0.05). An acute increase of GH ( P < 0.05), remaining elevated up to 30 min ( P < 0.05) postloading, was observed only at posttraining. Both neural adaptations and the capacity of skeletal muscle to undergo training-induced hypertrophy even in older women explain the strength gains. The increases in the CSA of the QF occurred throughout its length but differed selectively between the individual muscles. The serum concentrations of hormones remained unaltered, but a low level of testosterone may be a limiting factor in training-induced muscle hypertrophy. The magnitude and time duration of the acute GH response may be important physiological indicators of anabolic adaptations during strength training even in older women.
To examine endogenous anabolic hormone and growth factor responses to various heavy resistance exercise protocols (HREPs), nine male subjects performed each of six randomly assigned HREPs, which consisted of identically ordered exercises carefully designed to control for load [5 vs. 10 repetitions maximum (RM)], rest period length (1 vs. 3 min), and total work effects. Serum human growth hormone (hGH), testosterone (T), somatomedin-C (SM-C), glucose, and whole blood lactate (HLa) concentrations were determined preexercise, midexercise (i.e., after 4 of 8 exercises), and at 0, 5, 15, 30, 60, 90, and 120 min postexercise. All HREPs produced significant (P less than 0.05) temporal increases in serum T concentrations, although the magnitude and time point of occurrence above resting values varied across HREPs. No differences were observed for T when integrated areas under the curve (AUCs) were compared. Although not all HREPs produced increases in serum hGH, the highest responses were observed consequent to the H10/1 exercise protocol (high total work, 1 min rest, 10-RM load) for both temporal and time integrated (AUC) responses. The pattern of SM-C increases varied among HREPs and did not consistently follow hGH changes. Whereas temporal changes were observed, no integrated time (AUC) differences between exercise protocols occurred. These data indicate that the release patterns (temporal or time integrated) observed are complex functions of the type of HREPs utilized and the physiological mechanisms involved with determining peripheral circulatory concentrations (e.g., clearance rates, transport, receptor binding). All HREPs may not affect muscle and connective tissue growth in the same manner because of possible differences in hormonal and growth factor release.
The quantitative analysis of haemoglobin oxygenation of contracting human muscle during weight-lifting exercise was studied noninvasively and directly using near-infrared spectroscopy. This method was developed as a three-wavelength method which confirmed the volume changes in oxygenated haemoglobin (oxy-Hb), deoxygenated haemoglobin (deoxy-Hb) and blood volume (total-Hb; Oxy-Hb+deoxy-Hb). Nine healthy adult men with various levels of training experience took part in the study. Ten repetition maximum (10 RM) one-arm curl exercise was performed by all the subjects. Results showed that at the beginning of the 10-RM exercise, rapid increases of deoxy-Hb and decreases of oxy-Hb were observed. In addition, total-Hb gradually increased during exercise. These results corresponded to the condition of arm blood flow experimentally restricted using a tourniquet in contact with the shoulder joint, and they showed the restriction of venous blood flow and an anoxic state occurring in the dynamically contracted muscle. In three sets of lifting exercise with short rest periods, these tendencies were accelerated in each set, while total-Hb volume did not return to the resting state after the third set for more than 90 s. These results would suggest that a training regimen emphasizing a moderately high load and a high number of repetitions, and a serial set with short rest periods such as usually performed by body builders, caused a relatively long-term anoxic state in the muscle.
Nine eumenorrheic women (age 24.11 +/- 4.28 yr) performed each of six randomly assigned heavy-resistance protocols (HREPs) on separate days during the early follicular phase of the menstrual cycle. The HREPs consisted of two series [series 1 (strength, S) and series 2 (hypertrophy, H)] of three protocols, each using identically ordered exercises controlled for load [5 vs. 10 repetitions maximum (RM)], rest period length (1 vs. 3 min), and total work (J) within each three-protocol series. Blood measures were determined pre-, mid- (after 4 of 8 exercises), and postexercise (0, 5, 15, 30, 60, 90, 120 min and 24 and 48 h). In series 1, a significant (P < 0.05) reduction in growth hormone (GH) was observed at 90 min postexercise for all three protocols. In series 2, the 10-RM protocol with 1-min rest periods (H10/1) produced significant increases above rest in GH concentrations at 0, 5, and 15 min postexercise, and the H10/1 and H5/1 protocols demonstrated significant reductions at 90 and 120 min postexercise. Cortisol demonstrated significant increases in response to the S10/3 protocol at 0 min, to the H10/1 protocol at midexercise and at 0 and 5 min postexercise, and to the H5/1 protocol at 5 and 15 min postexercise. No significant changes were observed in total insulin-like growth factor I, total testosterone, urea, or creatinine for any of the HREPs. Significant elevations in whole blood lactate and ammonia along with significant reductions in blood glucose were observed. Hormonal and metabolic blood variables measured in the early follicular phase of the menstrual cycle varied in response to different HREPs. The most dramatic increases above resting concentrations were observed with the H10/1 protocol, indicating that the more glycolytic HREPs may stimulate greater GH and cortisol increases.
The relation between the eccentric force developed during a countermovement and the mechanical power output was studied in squatting exercises under nominally isotonic load (50% of 1-repetition maximum). The subjects (n = 5) performed squatting exercises with a countermovement at varied deceleration rates before lifting the load. The ground reaction force and video images were recorded to obtain the power output of the body. Net muscle moments acting at hip, knee, and ankle joints were calculated from video recordings by using inverse dynamics. When an intense deceleration was taken at the end of downward movement, large eccentric force was developed, and the mechanical power subsequently produced during the lifting movement was consistently larger than that produced without the countermovement. Both maximal and mean power outputs during concentric actions increased initially with the eccentric force, whereas they began to decline when the eccentric force exceeded approximately 1.4 times the sum of load and body weight. Video-image analysis showed that this characteristic relation was predominantly determined by the torque around the knee joint. Electromyographic analyses showed no consistent increase in time-averaged integrated electromyograph from vastus lateralis with the power output, suggesting that the enhancement of power output is primarily caused by the prestretch-induced improvement of an intrinsic force-generating capability of the agonist muscle.
Acute and chronic hormonal responses to resistance training were evaluated in 11 college men who completed 12 weeks (33 sessions) of high volume resistance training. No differences in resting concentrations of growth hormone (GH), insulin-like growth factor-I, testosterone, or sex hormone-binding globulin occurred from pre- and posttraining in the trained vs. nontrained control group. However, cortisol (c) decreased 17% for both groups (p < 0.05). There were no differences in exercise-induced responses between Sessions 10 and 20, with all hormone concentrations increasing (p < 0.05) from pre- at mid- and post exercise session. However, after correction for plasma volume decreases, only C and GH showed differences, with C increased from mid- to postsession (48% 10th; 49% 20th), and GH increased from pre- at mid- and postsession for both sessions 10 (0.16 +/- 0.42 pre; 4.77 +/- 6.24 mid; 6.26 +/- 5.19 post; microg x L-1) and 20 (0.33 +/- 0.85 pre; 5.42 +/- 9.08 mid; 8.24 +/- 7.61 post; microg x L-1). Significant correlations (p< 0.05) existed only between absolute mean GH increases from presession and the degree of muscle fiber hypertrophy for type I (r = 0.70 mid, 0.74 post) and type II (r = 0.71 post) fibers. In conclusion, resistance training had no effect on resting serum hormone concentrations, whereas similar acute exercise responses occurred between the 10th and 20th training sessions.
The aim of this study was to determine the effects of 8 weeks of resistance training (RT) on the myoglobin concentration ([Mb]) in human skeletal muscle, and to compare the change in the [Mb] in two different RT protocols. The two types of protocol used were interval RT (IRT) of moderate to low intensity with a high number of repetitions and a short recovery time, and repetition RT (RRT) of high intensity with a low number of repetitions and a long recovery time. A group of 11 healthy male adults voluntarily participated in this study and were divided into IRT (n = 6) and RRT (n = 5) groups. Both training protocols were carried out twice a week for 8 weeks. At the completion of the training period, the one-repetition maximal force values and isometric force were increased significantly in all the subjects, by about 38.8% and 26.0%, respectively (P < 0.01). The muscle fibre composition was unchanged by the 8 weeks of training. The muscle fibre cross-sectional areas were increased significantly by both types of training in all fibre types (I, IIa and IIb, mean + 16.1 %, P < 0.05). The [Mb] showed no significant changes at the completion of the training [IRT from 4.63 (SD 0.63) to 4.48 (SD 0.72), RRT from 4.47 (SD 0.75) to 4.24 (SD 0.80) mg x g(-1) wet tissue] despite a significant decrease in citrate synthase activity [IRT from 5.27 (SD 1.45) to 4.49 (SD 1.48), RRT from 5.33 (SD 2.09) to 4.85 (SD 1.87) micromol x min(-1) x g(-1) wet tissue; P < 0.05] observed after both protocols. These results suggested that myoglobin and mitochondria enzymes were regulated by different mechanisms in response to either type of RT. Moreover, the maintained [Mb] in hypertrophied muscle should preserve oxygen transport from capillaries to mitochondria even when diffusion distance is increased.
The purpose of this investigation was to determine the long-term training adaptations associated with low-volume circuit-type versus periodized high-volume resistance training programs in women.
34 healthy, untrained women were randomly placed into one of the following groups: low-volume, single-set circuit (SSC; N = 12); periodized high-volume multiple-set (MS; N = 12); or nonexercising control (CON) group (N = 10). The SSC group performed one set of 8-12 repetitions to muscular failure 3 d x wk(-1). The MS group performed two to four sets of 3-15 repetitions with periodized volume and intensity 4 d x wk(-1). Muscular strength, power, speed, endurance, anthropometry, and resting hormonal concentrations were determined pretraining (T1), after 12 wk (T2), and after 24 wk of training (T3).
1-RM bench press and leg press, and upper and lower body local muscular endurance increased significantly (P < or = 0.05) at T2 for both groups, but only MS showed a significant increase at T3. Muscular power and speed increased significantly at T2 and T3 only for MS. Increases in testosterone were observed for both groups at T2 but only MS showed a significant increase at T3. Cortisol decreased from T1 to T2 and from T2 to T3 in MS. Insulin-like growth factor-1 increased significantly at T3 for SSC and at T2 and T3 for MS. No changes were observed for growth hormone in any of the training groups.
Significant improvements in muscular performance may be attained with either a low-volume single-set program or a high-volume, periodized multiple-set program during the first 12 wk of training in untrained women. However, dramatically different training adaptations are associated with specific domains of training program design which contrast in speed of movement, exercise choices and use of variation (periodization) in the intensity and volume of exercise.
Effects of strength training (ST) for 21 wk were examined in 10 older women (64 +/- 3 yr). Electromyogram, maximal isometric force, one-repetition maximum strength, and rate of force development of the leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris (QF) and of vastus lateralis (VL), medialis (VM), intermedius (VI) and rectus femoris (RF) throughout the lengths of 3/12--12/15 (Lf) of the femur, muscle fiber proportion and areas of types I, IIa, and IIb of the VL were evaluated. Serum hormone concentrations of testosterone, growth hormone (GH), cortisol, and IGF-I were analyzed for the resting, preexercise, and postexercise conditions. After the 21-wk ST, maximal force increased by 37% (P < 0.001) and 1-RM by 29% (P < 0.001), accompanied by an increase (P < 0.01) in rate of force development. The integrated electromyograms of the vastus muscles increased (P < 0.05). The CSA of the total QF increased (P < 0.05) throughout the length of the femur by 5--9%. The increases were significant (P < 0.05) at 7/15--12/15 Lf for VL and at 3/15--8/15 Lf for VM, at 5/15--9/15 for VI and at 9/15 (P < 0.05) for RF. The fiber areas of type I (P < 0.05), IIa (P < 0.001), and IIb (P < 0.001) increased by 22--36%. No changes occurred during ST in serum basal concentrations of the hormones examined, but the level of testosterone correlated with the changes in the CSA of the QF (r = 0.64, P < 0.05). An acute increase of GH (P < 0.05), remaining elevated up to 30 min (P < 0.05) postloading, was observed only at posttraining. Both neural adaptations and the capacity of skeletal muscle to undergo training-induced hypertrophy even in older women explain the strength gains. The increases in the CSA of the QF occurred throughout its length but differed selectively between the individual muscles. The serum concentrations of hormones remained unaltered, but a low level of testosterone may be a limiting factor in training-induced muscle hypertrophy. The magnitude and time duration of the acute GH response may be important physiological indicators of anabolic adaptations during strength training even in older women.
The present investigation has been designed to confirm the effect of instruction (hard-and-fast instruction compared to fast instruction) upon maximal voluntary isometric force (MVF) and maximal rate of force development (MRFD) in muscle groups which differ with regards to muscle mass and usage. In addition, we took advantage of the force data collected during unilateral and bilateral leg extension, to compare the instruction effects on the indices of the bilateral deficits (BI, the differences between the data collected during bilateral extensions and the sum of the data collected during unilateral left and right extensions) with regard to MVF (BIMVF) and MRFD (BIMRFD). Force-time curves were recorded during maximal isometric contractions of the elbow flexors, the leg extensors of the take-off and lead legs and during bilateral leg extension in 26 healthy young male volunteers from the track-and-field national team of Tunisia. In the first protocol, the subjects were instructed to produce MFV as hard-and-fast as possible (instruction I). In the second protocol (instruction II) the subjects were instructed to provide MFRD, that is the most explosive force, by concentrating on the fastest contraction without concern for achieving maximal force. The present study confirmed the importance of an appropriate instruction for the measurement of MRDF The MRFD (F = 40.8, P < 0.001) were significantly higher when measured after instruction II compared to instruction I. The effect of the instruction upon MRFD were similar for muscle groups with different volumes, cortical representations and uses. The same results (F = 52.1; P < 0.001) were observed when MRFD was related to MVF [MRFD% = (MRFD/MVF) x 100]. On the other hand, MVF was similar following both instructions (ANOVA, F = 0.562; P = 0.454). Moreover, the results of the present study suggested that the effect of instruction was significantly larger for BIMRFD than for BIMVF.
The purpose of the present study was to examine the effects of an additional set immediately following high intensity resistance exercise on growth hormone (GH) response.
Subjects (n=8) performed 4 resistance exercise protocols (bilateral knee extension exercise) on separate days. The protocols were categorized into 2 types of protocol, namely "Strength-up type (S-type)" and "Combination type (Combi-type)". The S-type was resistance exercise which consisted of 5 sets at 90% of 1 repetition maximum (RM) with 3-min rest periods between sets, whereas the Combi-type is a training protocol which adds an additional set (either 50% of 1 RM [C50-type], 70% of 1 RM [C70-type] or 90% of 1 RM [C90-type]) to the S-type. Serum GH concentration and blood lactate concentration were determined pre-exercise and at 0-60 min postexercise. Relative changes in thigh girth and maximal unilateral isometric strength were determined pre-exercise and immediately postexercise.
The increasing values of GH concentration (DGH) in the S-type was the lowest of all protocols. On the other hand, DGH in the C50-type showed a significantly (p<0.05) higher increase than in the S-type and C90-type, and a relatively higher increase than in the C70-type.
These results suggests that a high intensity, low volume training protocol to induce neural adaptation resulted in little GH response, but GH secretion was increased by performing a single set of low intensity resistance exercise at the end of a series of high intensity resistance sets.
Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the "strength-endurance continuum". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, prolonged contractions, with significant increases after training in aerobic power and time to exhaustion. Thus, low and intermediate RM training appears to induce similar muscular adaptations, at least after short-term training in previously untrained subjects. Overall, however, these data demonstrate that both physical performance and the associated physiological adaptations are linked to the intensity and number of repetitions performed, and thus lend support to the "strength-endurance continuum".
The growth-promoting actions of a number of hormones on muscle have been studied by a number of investigators during the past two decades, and some reasonably solid conclusions can now be reached. The somatomedins and insulin are major stimulators of anabolic processes in skeletal muscle; the last remaining uncertainty (absence of evidence that the somatomedins could replace growth hormone in stimulating weight gain in hypophysectomized animals) has recently been removed. The situation with growth hormone is less clear. Evidence from studies on isolated diaphragm muscles is consistent in indicating responsiveness to growth hormone, but most of it was obtained using supraphysiological levels of the hormone, and (in contrast to somatomedin and insulin) it has not been possible to demonstrate direct effects of this hormone on isolated muscle cells. There are some similar problems in the case of insulin—it is not clear to what extent the anabolic actions of insulin can be attributed to its cross-reaction with the somatomedin receptor and/or its effects on energy metabolism, but there is recent convincing evidence that this hormone has direct anabolic effects on muscle cells in culture. The effects of androgens are much more apparent in the whole animal than in isolated muscles or cell culture systems, and they have been more difficult to characterize. The thyroid hormones are clearly required for normal growth and development in the intact animal, but there is not much information on their actions on isolated muscle or cultured cells. Surprisingly, Cortisol exhibits some growth-promoting effects, but these may be attributable to maintenance of the cells in a “healthy” state rather than to a direct stimulation of anabolic processes. In no case is there any detailed biochemical information on the mechanisms by which any of these growth-promoting actions occur, although it is reasonable to infer that the presence of a cytoplasmic receptor for testosterone in muscle indicates a typical steroid-induced activation of RNA synthesis and a resultant increase in protein synthesis. Thus, although a good deal of progress has been made in cataloging the hormones most likely to have direct effects on the growth of muscle, much remains to be done in determining just how those hormones act.
A training experiment was carried out to investigate the difference in training effects between power-up type and bulk-up type strength training exercises from the aspects of muscle histochemical properties and capillary supply. The subjects were eleven healthy males. The power-up type group (five males) performed knee extension exercise for 5 sets at 90% of 1 RM (one repetition maximum) with a 3-min rest between sets (repetition method). The bulk-up type group (six males) performed the same exercise for 9 sets at 80-40% of 1RM with a 30-s or 3-min rest between sets (interval method, multi-poundage system). Both programs were carried out twice a week for 8 weeks. The main results were as follows ; 1. Percentages of fiber types showed no recognizable changes in either group. 2. Fiber area was significantly increased for all fiber types (Type I, Type IIA, Type IIB) in both groups. However, the rate of increase was greatest for type IIA fiber, followed by type IIB fiber and then type I fiber. Moreover, the rate of increase for all fiber types in the bulk-up group was higher than that in the power-up group. 3. Percentage of fiber area showed no recognizable changes for any fiber types in the power-up group. However, the percentage area of type II fibers, especially type IIB fiber, was significantly decreased in the bulk-up group. 4. CC (Type I), CC (Type IIA) and CC (Type IIB) (number of capillaries in contact with each fiber type) were significantly increased in both groups. However, in comparison with CC (Type I). CC (Type IIA · Type HB) showed a higher rate of increase in the power-up group. On the other hand, in comparison with CC (Type IIA · Type IIB), CC (Type I) showed a higher rate of increase in the bulk-up group. Also, compared with the power-up group, the bulk-up group showed a significantly higher rate of increase of CC (Type I). 5. C/Fiber area (Type I), C/Fiber area (Type IIA) and C/Fiber area (Type IIB) (number of capillaries supplying each fiber area) were decreased in both groups. The above results show that power-up type exercise leads mainly to hypertrophy of type I, type IIA and type IIB fibers without any change in percentage fiber type or percentage fiber area, whereas bulk-up type exercise leads mainly to hypertrophy of each fiber type with decreases in percentage area of type II fibers, especially type IIB fiber. Also, power-up type exercise leads mainly to an increase in the number of capillaries around type II fibers, whereas bulk-up type exercise leads mainly to an increase in the number of capillaries around type I fiber. However, capillary development around all fiber types did not necessary coincide with muscle hypertrophy in either exercise. The authors reported previously that power-up type exercise is effective mainly for improving muscular strength and anaerobic power, whereas bulk-up type exercise is effective mainly for inducing hypertrophy and anaerobic endurance. The results of this study may help to clarify these effects from the viewpoint of the adaptations of muscle fibers and the capillary supply.
1. Increases in strength and size of the quadriceps muscle have been compared during 12 weeks of either isometric or dynamic strength training. 2. Isometric training of one leg resulted in a significant increase in force (35 +/- 19%, mean +/- S.D., n = 6) with no change in the contralateral untrained control leg. 3. Quadriceps cross-sectional area was measured from mid-thigh X-ray computerized tomography (c.t.) scans before and after training. The increase in area (5 +/- 4.6%, mean +/- S.D., n = 6) was smaller than, and not correlated with, the increase in strength. 4. The possibility that the stimulus for gain in strength is the high force developed in the muscle was examined by comparing two training regimes, one where the muscle shortened (concentric) and the other where the muscle was stretched (eccentric) during the training exercise. Forces generated during eccentric training were 45% higher than during concentric training. 5. Similar changes in strength and muscle cross-sectional area were found after the two forms of exercise. Eccentric exercise increased isometric force by 11 +/- 3.6% (mean +/- S.D., n = 6), and concentric training by 15 +/- 8.0% (mean +/- S.D., n = 6). In both cases there was an approximate 5% increase in cross-sectional area. 6. It is concluded that as a result of strength training the main change in the first 12 weeks is an increase in the force generated per unit cross-sectional area of muscle. The stimulus for this is unknown but comparison of the effects of eccentric and concentric training suggest it is unlikely to be solely mechanical stress or metabolic fluxes in the muscle.
Variation or periodization of training is an important concept in designing weight-training programs. To date, the majority of studies examining periodization of weight training have used a traditional strength/power training model of decreasing training volume and increasing training intensity as the program progresses. The majority of these studies have used males as subjects and do support the contention that periodized programs can result in greater changes in strength, motor performance, total body weight, lean body mass, and percent body fat than nonperiodized programs. However, studies are needed examining why periodized training is more beneficial than nonperiodized training. Studies are also needed examining the response of females, children, and seniors to periodized weight-training programs and the response to periodized models other than the traditional strength/power training model.
The purpose of the study was to determine the optimum number of repetitions with which to train for quickest strength improvement. Nine groups, consisting of a total of 199 male college students, were tested before and after 12 weeks of progressive resistance exercise. Each group trained differently in repetitions per set. Resistances employed were 2 RM, 4 RM, 6 RM, 8 RM, 10 RM, and 12 RM for one set. The optimum number of repetitions was found to be between 3 and 9.
The first part of this series of articles discussed basic concepts of resistance training; parts 2 and 3 continued with a discussion of physiological responses and adaptations that occur as a result of such training. In this fourth and concluding article, the authors discuss resistance training as exercise prescription and outline the program design process. They point out the importance of making preliminary assessments; defining specific goals and expectations; and evaluating the individual needs, goals, and demands of the participants to help them benefit from the program as much as possible.
Variation or periodization of training is an important concept in designing weight-training programs. To date, the majority of studies examining periodization of weight training have used a traditional strength/power training model of decreasing training volume and increasing training intensity as the program progresses. The majority of these studies have used males as subjects and do support the contention that periodized programs can result in greater changes in strength, motor performance, total body weight, lean body mass, and percent body fat than nonperiodized programs. However, studies are needed examining why periodized training is more beneficial than nonperiodized training. Studies are also needed examining the response of females, children, and seniors to periodized weight-training programs and the response to periodized models other than the traditional strength/power training model.
(C) 1999 National Strength and Conditioning Association
Effects of 6 mo of heavy-resistance training combined with explosive exercises on neural activation of the agonist and antagonist leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris, as well as maximal and explosive strength were examined in 10 middle-aged men (M40; 42 +/- 2 yr), 11 middle-aged women (W40; 39 +/- 3 yr), 11 elderly men (M70; 72 +/- 3 yr) and 10 elderly women (W70; 67 +/- 3 yr). Maximal and explosive strength remained unaltered during a 1-mo control period with no strength training. After the 6 mo of training, maximal isometric and dynamic leg-extension strength increased by 36 +/- 4 and 22 +/- 2% (P < 0. 001) in M40, by 36 +/- 3 and 21 +/- 3% (P < 0.001) in M70, by 66 +/- 9 and 34 +/- 4% (P < 0.001) in W40, and by 57 +/- 10 and 30 +/- 3% (P < 0.001) in W70, respectively. All groups showed large increases (P < 0.05-0.001) in the maximum integrated EMGs (iEMGs) of the agonist vastus lateralis and medialis. Significant (P < 0.05-0.001) increases occurred in the maximal rate of isometric force production and in a squat jump that were accompanied with increased (P < 0.05-0. 01) iEMGs of the leg extensors. The iEMG of the antagonist biceps femoris muscle during the maximal isometric leg extension decreased in both M70 (from 24 +/- 6 to 21 +/- 6%; P < 0.05) and in W70 (from 31 +/- 9 to 24 +/- 4%; P < 0.05) to the same level as recorded for M40 and W40. The CSA of the quadriceps femoris increased in M40 by 5% (P < 0.05), in W40 by 9% (P < 0.01), in W70 by 6% (P < 0.05), and in M70 by 2% (not significant). Great training-induced gains in maximal and explosive strength in both middle-aged and elderly subjects were accompanied by large increases in the voluntary activation of the agonists, with significant reductions in the antagonist coactivation in the elderly subjects. Because the enlargements in the muscle CSAs in both middle-aged and elderly subjects were much smaller in magnitude, neural adaptations seem to play a greater role in explaining strength and power gains during the present strength-training protocol.
Plasma growth hormone (GH) responses to various stimuli were examined in 21 patients with GH-producing pituitary adenomas, classified into three types by the immunohistochemistry of cytokeratin and the glycoprotein hormone alpha-subunit distribution. Seven type 1 adenomas were exclusively composed of cells in which the cytokeratin formed a dot-like pattern; they were chromophobic to hematoxylin and eosin (H&E), occasionally positive for GH, and almost completely negative for the alpha-subunit. Thirteen type 2 adenomas were composed of cells with cytokeratin that had a perinuclear distribution; they were eosinophilic to H&E, and diffusely positive for both GH and the alpha-subunit. One patient had a type 3 adenoma which had a mixed pattern of intracellular cytokeratin distribution and was chromophobic and eosinophilic to H&E. Clinically, type 1 is characterized by earlier onset, larger tumor size, and more frequent aggressive extension. Paradoxical GH responses to TRH and OGTT were seen in 1 of 6 patients (16.7%) of type 1 and 8 of 9 patients (88.9%) of type 2, and 0% of type 1 and 62.5% of type 2, respectively. Type 2 cases showed higher plasma GH response to GH-releasing hormone, and a tendency to greater suppression of plasma GH by bromocriptine compared with type 1. Octreotide acetate administration revealed that the nadir/basal ratio of plasma GH levels was 42.9 +/- 6.6% in type 1 and 13.5 +/- 5.8% in type 2. These results suggest that there is a pathophysiological difference between these two distinct types of GH-producing pituitary adenomas.
In muscle of whole animals, pituitary growth hormone, the thyroid hormones, and insulin are major growth-promoting hormones, and the glucocorticoids have significant catabolic actions. At the cellular level the primary anabolic hormones for cultured myoblasts are the somatomedins (insulin-like growth factors) and fibroblast growth factor. In these cells physiological concentrations of growth hormone, thyroid hormones, and insulin have no growth-promoting effect; some of the reported actions of insulin probably result from cross-reaction with the somatomedin receptor. Results with purified proteins do not support the view that mitogens block myoblast differentiation; transforming growth factor-beta and interferon are nonmitogenic proteins that inhibit differentiation, insulin-like growth factors are mitogens that stimulate differentiation, and fibroblast growth factor is the only purified mitogen that inhibits differentiation. At least six serum-free media have now been devised for the growth of various kinds of muscle cells under closely defined conditions.
Heavy-resistance exercise utilizing very short rest periods is commonly used by body builders to prepare for competition. The purpose of this study was to compare the acute responses of this type of heavy-resistance exercise protocol in competitive body builders (BB) and power lifters (PL). Nine male BB and eight PL were matched for age, size and experience. A ten-station heavy-resistance exercise protocol was used. Each subject performed three sets of 10 repetition maximum (RM) with 10-s rest between sets and alternated 30-s and 60-s rest periods between exercises. No differences were observed in total work between the groups, but BB used a significantly (P less than 0.05) higher percentage of their 1 RM in the bench press and leg press exercises. Heart rate, ratings of perceived exertion (RPE), and lactate levels were obtained during the exercise protocol; significant (P less than 0.05) increases were observed above rest for these variables. RPE was significantly correlated with lactate levels (r = 0.84). Plasma epinephrine, norepinephrine, dopamine, cortisol, and lactate levels significantly increased from pre- to 5 min post-exercise. Mean plasma volumes were reduced -16.6 (+/- 3.64)% and -20.6 (+/- 8.32)% following the exercise protocol for BB and PL, respectively. Significant (P less than 0.05) decreases in eosinophil counts were observed following exercise. No significant differences were observed between BB and PL for any of the physiologic responses measured. PL exhibited a higher incidence (100%) of clinical symptoms of dizziness and nausea compared to BB (11.1%).(ABSTRACT TRUNCATED AT 250 WORDS)
To examine endogenous hormonal responses to heavy-resistance exercise, ten male strength athletes performed two fatiguing but different types of sessions on separate days. In session A the loads for the leg extensor muscles in the squat-lift exercise were maximal so that the subjects performed 20 sets at 1 repetition maximum (RM) (20 x 1 RM x 100%), whereas during session B the loads were submaximal (70%) but the subjects performed each of the 10 sets until the RM (i.e., 10 repetitions/set or 10 x 10 x 70%). The recovery time between the sets was always 3 min. A decrease of 10.3 +/- 4.7% (P < 0.001) occurred in the squat-lift in 1 RM during session A, whereas session B led to a decrease of 24.6 +/- 18.9% (P < 0.001) in 10 RM. Increases in the concentrations of serum total and free testosterone (P < 0.05 and 0.05, respectively), cortisol (P < 0.001), and growth hormone (GH, P < 0.001) were observed during session B, whereas the corresponding changes during session A were statistically insignificant except for the relatively slight increase (P < 0.01) in serum GH level. The significant (P < 0.001) increase in blood lactate concentration during the two sessions correlated significantly (P < 0.01) with the increase in serum GH concentration. The morning values of serum testosterone and free testosterone were significantly (P < 0.05-0.001) lowered on the 1st and 2nd rest days after the sessions.(ABSTRACT TRUNCATED AT 250 WORDS)
Concurrent strength and endurance training appears to inhibit strength development when compared with strength training alone. Our understanding of the nature of this inhibition and the mechanisms responsible for it is limited at present. This is due to the difficulties associated with comparing results of studies which differ markedly in a number of design factors, including the mode, frequency, duration and intensity of training, training history of participants, scheduling of training sessions and dependent variable selection. Despite these difficulties, both chronic and acute hypotheses have been proposed to explain the phenomenon of strength inhibition during concurrent training. The chronic hypothesis contends that skeletal muscle cannot adapt metabolically or morphologically to both strength and endurance training simultaneously. This is because many adaptations at the muscle level observed in response to strength training are different from those observed after endurance training. The observation that changes in muscle fibre type and size after concurrent training are different from those observed after strength training provide some support for the chronic hypothesis. The acute hypothesis contends that residual fatigue from the endurance component of concurrent training compromises the ability to develop tension during the strength element of concurrent training. It is proposed that repeated acute reductions in the quality of strength training sessions then lead to a reduction in strength development over time. Peripheral fatigue factors such as muscle damage and glycogen depletion have been implicated as possible fatigue mechanisms associated with the acute hypothesis. Further systematic research is necessary to quantify the inhibitory effects of concurrent training on strength development and to identify different training approaches that may overcome any negative effects of concurrent training.
The release of a bioassayable form of growth hormone (BGH), distinct from growth hormone as measured by immunoassay (IGH), from the rat pituitary into the blood is differentially regulated by afferent input from fast and slow skeletal muscles. Specifically, activation of low-threshold fast muscle afferents for 15 min increased plasma BGH by 217 and 295% and decreased pituitary BGH by 68 and 45% in male and female rats, respectively. In contrast, activation of slow muscle afferents inhibited BGH release, decreasing plasma BGH by approximately 60% and increasing pituitary BGH by 30-50% in male rats. Female rats from which food had been withheld for approximately 12 h had elevated basal plasma BGH levels, which then were decreased by 81% after slow muscle nerve stimulation. Plasma IGH concentrations were unchanged after any nerve stimulation condition. These results demonstrate that regulation of BGH release can be differentially mediated through low-threshold afferent inputs from fast or slow skeletal muscle. Furthermore, the results indicate that BGH responses are independent of gender or feeding status.
The difference between effects of ''power-up type'' and ''bulk-up type'' strength training exercises (2)—with special reference to muscle fiber characteristics and capillary supply (in Japanese with English abstract)