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Varying the Order of Combinations of Single- and Multi-Joint Exercises Differentially Affects Resistance Training Adaptations
Abstract
Brandão, L, de Salles Painelli, V, Lasevicius, T, Silva-Batista, C, Brendon, H, Schoenfeld, BJ, Aihara, AY, Cardoso, FN, de Almeida Peres, B, and Teixeira, EL. Varying the order of combinations of single- and multi-joint exercises differentially affects resistance training adaptations. J Strength Cond Res XX(X): 000-000, 2020-Our study aimed to compare the effects of multi-joint (MJ) and single-joint (SJ) exercises, either isolated or in combination, and in different orders, on cross-sectional area (CSA) of the pectoralis major (PM) and different heads of the triceps brachii (TB), as well as on the one-repetition maximum (1-RM) in the bench press and lying barbell triceps press. Forty-three young men were randomly assigned to one of 4 possible RT protocols: barbell bench press plus lying barbell triceps press (MJ + SJ, n = 12); lying barbell triceps press plus barbell bench press (SJ + MJ, n = 10); barbell bench press (MJ, n = 10); or lying barbell triceps press (SJ, n = 11). Results showed significant within-group increases in 1-RM bench press for MJ, MJ + SJ, and SJ + MJ but not for SJ. Conversely, significantly greater within-group increases in elbow extension 1-RM were noted for SJ, MJ + SJ, and SJ + MJ but not for MJ. Significantly greater increases in PM CSA were observed for MJ, MJ + SJ, and SJ + MJ compared with SJ. Significant increases in TB CSA were noted for SJ, MJ + SJ, and SJ + MJ, but not for MJ, without observed between-group differences. Individual analysis of TB heads showed significantly greater CSA increases in the lateral head for MJ, MJ + SJ, and SJ + MJ compared with SJ. Alternatively, significantly greater increases in the long head were observed for SJ, MJ + SJ, and SJ + MJ compared with MJ. CSA increases for the medial head were statistically similar between conditions. Our findings indicate that muscular adaptations are differentially affected by performance of MJ and SJ exercises.
... Furthermore, previous meta-analyses have quantified all sets for a given muscle group as equal whether it is the primary force generating muscle (e.g., pectoralis major in the bench press) or a synergist muscle (e.g., triceps brachii in the bench press). However, some data suggest synergists may experience less hypertrophy than the primary force generator (10,11). Nonetheless, the evidence remains unclear regarding how to quantify synergist muscle set volume accurately (12,13). ...
... The support for the 'fractional' quantification method can be categorized as 'strong,' or 'very strong' per the Kass and Raftery scale (52). Indeed, it is unlikely that any involvement of a muscle group in an RT set should be quantified equally for muscle hypertrophy (10)(11)(12)(13). For instance, direct sets are likely to expose the primary force-generating muscle to a closer proximity to failure, which may enhance the hypertrophic training stimulus (109). ...
... For instance, direct sets are likely to expose the primary force-generating muscle to a closer proximity to failure, which may enhance the hypertrophic training stimulus (109). Regarding muscle strength, indirect sets generally contribute to the strength assessment but are unlikely to be as effective as the specific movement (10,11,110). ...
Background: Weekly set volume and frequency are used to manipulate resistance training (RT) dosage. Previous research has identified higher weekly set volume as enhancing muscle hypertrophy and strength gains, but the nature of the dose-response relationship still needs to be investigated. Mixed evidence exists regarding the effects of higher weekly frequency. Objective: Before meta-analyzing the volume and frequency research, all contributing RT sets were classified as direct or indirect, depending on their specificity to the hypertrophy/strength measurement. Then, weekly set volume/frequency for indirect sets was quantified as 1 for 'total,' 0.5 for 'fractional,' and 0 for 'direct.' A series of multi-level meta-regressions were performed for muscle hypertrophy and strength, utilizing 67 total studies of 2,058 participants. All models were adjusted for the duration of the intervention and training status. Results: The relative evidence for the 'fractional' quantification method was strongest; therefore, this quantification method was used for the primary meta-regression models. The posterior probability of the marginal slope exceeding zero for the effect of volume on both hypertrophy and strength was 100%, indicating that gains in muscle size and strength increase as volume increases. However, both best fit models suggest diminishing returns, with the diminishing returns for strength being considerably more pronounced. The posterior probability of the marginal slope exceeding zero for frequency's effect on hypertrophy was less than 100%, indicating compatibility with negligible effects. In contrast, the posterior probability for strength was 100%, suggesting strength gains increase with increasing frequency, albeit with diminishing returns. Conclusions: Distinguishing between direct and indirect sets appears essential for predicting adaptations to a given RT protocol, such as using the 'fractional' quantification method. This method's dose-response models revealed that volume and frequency have unique dose-response relationships with each hypertrophy and strength gain. The dose-response relationship between volume and hypertrophy appears to differ from that with strength, with the latter exhibiting more pronounced diminishing returns. The dose-response relationship between frequency and hypertrophy appears to differ from that with strength, as only the latter exhibits consistently identifiable effects.
... At the end of the experimental period, only the groups performing low and moderate repetitions presented significant increments in cross-sectional area (CSA) of type I, IIa and IIx muscle fibers, highlighting that lower intensities might be sub-optimal in promoting increases in muscle size. Conversely, Schoenfeld et al. (95) observed no differences in the magnitude of muscle thickness increase when comparing low (25-35RM) and moderate (8)(9)(10)(11)(12) loads. However, larger increments in maximal strength were observed for the latter condition. ...
... vs 5.1%, respectively). Similarly, the CSA from the three heads of the triceps muscle only increased when both SJ (lying barbell triceps) and MJ (barbell bench press) exercises were performed by untrained men after 10 weeks (12). ...
... Together, these findings suggest that individuals aiming to maximally and/or symmetrically increase muscle size may beneficiate from a wide range of exercises, especially when combining MJ and SJ movements. Notwithstanding, extrapolations must be done with some caution since most of these studies included only untrained participants (12,63,109). Therefore, additional studies with advanced lifters must be addressed to better understand the effects of combining MJ and SJ exercises on morphological outcomes. ...
International Journal of Exercise Science 15(4): 910-933, 2022. The regular practice of resistance training (RT) has been shown to induce relevant increases in both muscle strength and size. In order to maximize these adaptations, the proper manipulation of RT variables is warranted. In this sense, the aim of the present study was to review the available literature that has examined the application of the acute training variables and their influence on strength and morphological adaptations of healthy young adults. The information presented in this study may represent a relevant approach to proper training design. Therefore, strength and conditioning coaches may acquire a fundamental understanding of RT-variables and the relevance of their practical application within exercise prescription.
... At the end of the experimental period, only the groups performing low and moderate repetitions presented significant increments in cross-sectional area (CSA) of type I, IIa and IIx muscle fibers, highlighting that lower intensities might be sub-optimal in promoting increases in muscle size. Conversely, Schoenfeld et al. (95) observed no differences in the magnitude of muscle thickness increase when comparing low (25-35RM) and moderate (8)(9)(10)(11)(12) loads. However, larger increments in maximal strength were observed for the latter condition. ...
... vs 5.1%, respectively). Similarly, the CSA from the three heads of the triceps muscle only increased when both SJ (lying barbell triceps) and MJ (barbell bench press) exercises were performed by untrained men after 10 weeks (12). ...
... Together, these findings suggest that individuals aiming to maximally and/or symmetrically increase muscle size may beneficiate from a wide range of exercises, especially when combining MJ and SJ movements. Notwithstanding, extrapolations must be done with some caution since most of these studies included only untrained participants (12,63,109). Therefore, additional studies with advanced lifters must be addressed to better understand the effects of combining MJ and SJ exercises on morphological outcomes. ...
International Journal of Exercise Science 15(4): X-Y, 2022. The regular practice of resistance training (RT) has been shown to induce relevant increases in both muscle strength and size. In order to maximize these adaptations, the proper manipulation of RT variables is warranted. In this sense, the aim of the present study was to review the available literature that has examined the application of the acute training variables and their influence on strength and morphological adaptations of healthy young adults. The information presented in this study may represent a relevant approach to proper training design. Therefore, strength and conditioning coaches may acquire a fundamental understanding of RT-variables and the relevance of their practical application within exercise prescription.
... This discussion seems to be relevant for future studies about the PE method. Considering that, the selection of the exercises can directly interfere in the morphological adaptations of the target muscle itself (6). For example, while the bench press exercise is effective for the hypertrophy of the major pectoralis and triceps brachii (24), a greater hypertrophy for the major pectoralis is observed when compared to the triceps brachii, and it is not effective for the long head of the triceps brachii itself (6,24). ...
... Considering that, the selection of the exercises can directly interfere in the morphological adaptations of the target muscle itself (6). For example, while the bench press exercise is effective for the hypertrophy of the major pectoralis and triceps brachii (24), a greater hypertrophy for the major pectoralis is observed when compared to the triceps brachii, and it is not effective for the long head of the triceps brachii itself (6,24). In this case, the "lying triceps extension" could be used as PE, as additional stimuli for hypertrophy of the long head of the triceps brachii (6,36). ...
... For example, while the bench press exercise is effective for the hypertrophy of the major pectoralis and triceps brachii (24), a greater hypertrophy for the major pectoralis is observed when compared to the triceps brachii, and it is not effective for the long head of the triceps brachii itself (6,24). In this case, the "lying triceps extension" could be used as PE, as additional stimuli for hypertrophy of the long head of the triceps brachii (6,36). ...
Pre-exhaustion (PE) is a popular resistance training strategy that involves performing a single-joint exercise followed by a multi-joint exercise with minimal recovery between the transition. This approach is widely used by bodybuilding athletes and resistance training (RT) enthusiasts with the aim of enhancing muscle strength and hypertrophy. The present paper aimed to provide a narrative review as to the effects of the PE method on different acute and chronic outcomes, and discuss relevant practical applications. When considering the body of literature as a whole, we conclude that current evidence does not support a benefit to the PE method compared to traditional RT models regarding chronic improvements in strength, hypertrophy and body composition. However, the heterogeneous study designs confound the ability to draw strong conclusions on the topic. Further investigations are warranted with strict control of study variables to better elucidate what, if any, benefits may be obtained by the PE method.
... However, this article has been criticized for overextrapolation of evidence, calling into question its conclusions (31). Moreover, several controlled studies have been published subsequent to this review that shed further light on the topic (3,6,25). A more recent review concluded that SJ and MJ exercise appear to elicit similar hypertrophy of some muscles but that SJ exercise may promote additional hypertrophic effects in others (34). ...
... Of these results, the full texts of 9 studies were assessed for eligibility. Seven of these studies were deemed to meet inclusion criteria (3,6,8,13,25,35); 1 study was excluded for not employing a sitespecific measure of hypertrophy (30) and another study was excluded because the duration of the intervention lasted only 5 weeks (42). Secondary searches did not reveal any additionally relevant studies; thus, we analyzed a total of 7 studies. ...
... Visual inspection of the funnel plot revealed a symmetrical appearance, without any suggestion of publication bias; results of Egger's test support this conclusion (p 5 0.97; Figure 3). Influential case/outlier diagnostics indicated 2 comparisons from the study by Brandão et al. (6) to be influential, but their removal from the analysis did not meaningfully change the results. ...
We performed a systematic review and meta-analysis comparing the effects of single-joint (SJ) and multijoint (MJ) resistance exercises on muscle hypertrophy of the limb muscles. A systematic search was performed to identify randomized trials that directly compared hypertrophic changes between SJ and MJ resistance exercises, as well as combinations of the 2, in healthy adults. A total of 7 studies met inclusion criteria, comprising 10 nested comparisons. Meta-analysis indicated a trivial standardized point estimate with a relatively moderate precision for the confidence interval estimate. Subgroup analyses showed no effect on results when stratifying studies according to combined SJ + MJ versus MJ training alone, as well as under volume-equated or nonequated conditions. However, scrutiny of individual studies in conjunction with related indirect evidence collectively indicate that SJ exercise may provide the ability to preferentially hypertrophy muscular subdivisions, potentially promoting more complete muscle development. We conclude that current evidence indicates similar whole muscle hypertrophy between MJ and SJ training. There may be added benefit to combining SJ and MJ exercises for targeting individual aspects of a given muscle, although this hypothesis remains understudied. Future studies are needed to explore the effects of SJ and MJ exercises in resistance training on regional muscle hypertrophy.
... This discussion seems to be relevant for future studies about the PE method. Considering that, the selection of the exercises can directly interfere in the morphological adaptations of the target muscle itself (6). For example, while the bench press exercise is effective for the hypertrophy of the major pectoralis and triceps brachii (24), a greater hypertrophy for the major pectoralis is observed when compared to the triceps brachii, and it is not effective for the long head of the triceps brachii itself (6,24). ...
... Considering that, the selection of the exercises can directly interfere in the morphological adaptations of the target muscle itself (6). For example, while the bench press exercise is effective for the hypertrophy of the major pectoralis and triceps brachii (24), a greater hypertrophy for the major pectoralis is observed when compared to the triceps brachii, and it is not effective for the long head of the triceps brachii itself (6,24). In this case, the "lying triceps extension" could be used as PE, as additional stimuli for hypertrophy of the long head of the triceps brachii (6,36). ...
... For example, while the bench press exercise is effective for the hypertrophy of the major pectoralis and triceps brachii (24), a greater hypertrophy for the major pectoralis is observed when compared to the triceps brachii, and it is not effective for the long head of the triceps brachii itself (6,24). In this case, the "lying triceps extension" could be used as PE, as additional stimuli for hypertrophy of the long head of the triceps brachii (6,36). ...
International Journal of Exercise Science 15(3): 507-525, 2022. Pre-exhaustion (PE) is a popular resistance training strategy that involves performing a single-joint exercise followed by a multi-joint exercise with minimal recovery between the transition. This approach is widely used by bodybuilding athletes and resistance training (RT) enthusiasts with the aim of enhancing muscle strength and hypertrophy. The present paper aimed to provide a narrative review as to the effects of the PE method on different acute and chronic outcomes, and discuss relevant practical applications. When considering the body of literature as a whole, we conclude that current evidence does not support a benefit to the PE method compared to traditional RT models regarding chronic improvements in strength, hypertrophy and body composition. However, the heterogeneous study designs confound the ability to draw strong conclusions on the topic. Further investigations are warranted with strict control of study variables to better elucidate what, if any, benefits may be obtained by the PE method.
... With this, conclusions will be driven only regarding the effects of each exercise, improving the applicability of the findings [17]. Of note, this approach is what has been done most [62,[65][66][67][68][69][70][71][72][73][74][75][76][77][78], and is valid for studies comparing exercises of different numbers of joints involved (single vs. multi-joint), ranges of motion (full vs. partial), apparatus (machine vs. free-weight), angles (inclined vs. declined), and initial joint positions (stretched vs. shortened). ...
... The literature is controversial on this topic and does need more studies before trying to answer such questions or propose new metrics [83]. As an example, some studies showed that the triceps brachii hypertrophied 50% in comparison with the pectoralis major following a barbell chest-press training [68,87], which would indicate that the volume performed on the chest press for the triceps has to be counted as a half volume compared to the pectoralis major, that is, in a 0.5:1.0 ratio. ...
... ratio. Also, the triceps increased 50% in the chest press compared to the triceps extension exercise [68], which would indicate that 1 set of chest press has to be counted as a 0.5 set for the triceps. However, these results represent the outcomes on a group-mean basis, and some individuals might have presented different hypertrophy ratios between the muscles besides the 0.5:1.0. ...
Calculating resistance-training volume in programs focused on muscle hypertrophy is an attempt to quantify the external workload carried out, then to estimate the dose of stimulus imposed on targeted muscles. The volume is usually expressed in some variables that directly affected the total training work, such as the number of sets, repetitions, and volume-load. These variables are used to try to quantify the training work easily, for the subsequent organization and prescription of training programs. One of the main uses of measures of volume quantification is seen in studies in which the purpose is to compare the effects of different training protocols on muscle growth in a volume-equated format. However, it seems that not all measures of volume are always appropriate for equating training protocols. In the current paper, it is discussed what training volume is and the potentials and shortcomings of each one of the most common ways to equate it between groups depending on the independent variable to be compared (e.g., weekly frequency, intensity of load, and advanced techniques).
... 5 Despite the established international guidelines to support RT-induced muscle hypertrophy through the manipulation of variables such as intensity, volume, and interset resting interval, 7,18 the body of evidence investigating the influence of muscle length/joint angle on muscle hypertrophy during dynamic exercises is incipient and its findings are controversial. 2,16,17,20,29 Nevertheless, most studies indicate that muscle hypertrophy is optimized when RT is conducted at long versus short muscle lengths. 21 This might be attributed to the greater overall mechanical tension that occurs when a muscle is tensioned as it is lengthened, presumably due to active and passive tension overlapping, 22,30 although others speculate that muscle hypertrophy is likely attributable to greater metabolic stress and insulin-like growth factor-1 expression associated with exercise at long muscle lengths. ...
... 22,23 However, RT guidelines generally recommend dynamic exercises for both lower-and upper-body as well as with a full range of motion when possible. 7,18 Moreover, measures of muscle edema were not performed in most of the aforementioned chronic studies, 2,16,17,20,29 which is concerning due to the potential interference of this factor on muscle hypertrophy analysis. 26 In addition, the lack of regional hypertrophy analysis is also a hallmark in the previous studies, which may have impaired the interpretation of hypertrophy responses across muscles differently lengthened. ...
Background: We compared the regional hypertrophy response of the elbow flexor muscles after unilateral elbow flexion training performed in the extended versus flexed shoulder position under vascular occlusion, a method known to induce muscle hypertrophy in the absence of muscle damage-induced edema/swelling. Hypothesis: Hypertrophy of the elbow flexor muscles would be greater in the extended compared to flexed shoulder position. Study Design: Randomized within-subject trial. Level of Evidence: Level 2. Methods: Twenty-one recreationally resistance-trained men (25±5 y; 1.78±0.07 m; 79.3±13.1 kg) were submitted to unilateral elbow flexions with one shoulder extended/elbow flexor muscles lengthened/long muscle length (LONG) and the other shoulder flexed/elbow flexor muscles shortened/short muscle length (SHORT) under a low-load (30% one-repetition maximum) vascular occlusion training regimen. Training consisted of 15 reps/set, 4 sets/session, 4 sessions/week for 3 weeks, using 80% of the vascular occlusion pressure. The elbow flexor muscles cross sectional area (EFCSA) was measured pre- and post-training at 45%, 65% and 85% of humerus length through magnetic resonance imaging. Results: EFCSA significantly increased in both SHORT and LONG at 45% (respectively, P=0.04 and P=0.05) and 85% lengths (respectively, P=0.0001 and P=0.001). Changes in EFCSA between SHORT and LONG were statistically similar at the 45% (respectively, +6.20% vs. +5.08%, Cohen's d=0.006, P=0.984), 65% (respectively, +5.91% vs. +3.83%, Cohen's d=0.28, P=0.301) and 85% lengths (respectively, +8.51% vs. +7.38%, Cohen's d=0.18, P=0.563). Conclusions: Muscle hypertrophy of the elbow flexor muscles displayed a similar behavior after low-load elbow flexion training with vascular occlusion performed in the extended versus flexed shoulder position. Clinical Relevance: Therapists, clinicians and coaches may choose elbow flexion exercises expecting to achieve similar results for hypertrophy in this muscle group, implying that exercise selection may rely on the availability of equipment in the training room or personal preference.
... Just like with the biceps brachii, when all the training volume is counted, the direct training volume of the triceps brachii is less. However, as suggested by recent studies, such as Brandão et al. (2020), the growth of the triceps brachii is not uniform, and multi-joint exercises can affect more the lateral head, and single-joint exercises the long head. This suggests that a combination of these is important for triceps brachii hypertrophy and that, depending on where the measurements are taken (in the triceps brachii), results may vary due to regional hypertrophy (Zabaleta-Korta et al., 2020). ...
... Another reason to explain why greater results in HV are observed in the triceps brachii, as suggested by Brandão et al. (2020), is that the triceps brachii acts as a synergist and not as an agonist in many of the multi-joint exercises. Therefore, it may be necessary to build up a larger training volume with multi-joint exercises in order to achieve the same results. ...
The main goal of this study was to compare responses to moderate and high training volumes aimed at inducing muscle hypertrophy. A literature search on 3 databases (Pubmed, Scopus and Chocrane Library) was conducted in January 2021. After analyzing 2083 resultant articles, studies were included if they met the following inclusion criteria: a) studies were randomized controlled trials (with the number of sets explicitly reported), b) interventions lasted at least six weeks, c) participants had a minimum of one year of resistance training experience, d) participants' age ranged from 18 to 35 years, e) studies reported direct measurements of muscle thickness and/or the cross-sectional area, and f) studies were published in peer-review journals. Seven studies met the inclusion criteria and were included in the qualitative analysis, whereas just six were included in the quantitative analysis. All participants were divided into three groups: "low" (<12 weekly sets), "moderate" (12-20 weekly sets) and "high" volume (>20 weekly sets). According to the results of this meta-analysis, there were no differences between moderate and high training volume responses for the quadriceps (p = 0.19) and the biceps brachii (p = 0.59). However, it appears that a high training volume is better to induce muscle mass gains in the triceps brachii (p = 0.01). According to the results of this review, a range of 12-20 weekly sets per muscle group may be an optimum standard recommendation for increasing muscle hypertrophy in young, trained men.
... Now that we have determined that we must perform several exercises to maximize the hypertrophy of a muscle group, we must order them within the session. Although, as we mentioned before, there are no differences between performing global or analytical exercises, there are differences in how one affects the other, so it is important to know how the order in which they are programmed affects them [64], as the fatigue they generate is not the same. Placing the exercises of the target muscles at the beginning of the session could have slight advantages when it comes to optimizing the hypertrophy of these muscles due to the production capacity and increase in strength available at the beginning of the sessions [4]. ...
The present chapter delves into the topic of muscle hypertrophy in detail, focusing on defining what muscle hypertrophy is, the types of hypertrophy, the mechanisms, and the relationship with resistance training, as well as the variables affecting hypertrophy such as nutrition, rest, exercise selection, training volume, and training frequency, among others. The importance of mechanical tension, metabolic stress, and muscle damage as triggers for muscle hypertrophy is emphasized. Various types of muscle hypertrophy are explored, including connective tissue hypertrophy and sarcoplasmic and myofibrillar hypertrophy. The text also delves into how hypertrophy mechanisms relate to resistance training, highlighting the significance of mechanical tension and metabolic stress as stimuli for muscle hypertrophy. In a practical point of view, the text also discusses factors like nutrition and recovery, highlighting the importance of maintaining a positive energy balance and adequate protein intake to promote muscle growth optimally. Training variables such as exercise selection, exercise order, intensity, volume, frequency, and tempo of execution are discussed in detail, outlining their impact on muscle hypertrophy. The text provides a comprehensive overview of muscle hypertrophy, analyzing various factors that influence the ability to increase muscle mass. It offers detailed information on the biological mechanisms, types of hypertrophy, training strategies, and nutritional and recovery considerations necessary to achieve optimal results in terms of muscle hypertrophy.
... The sequence of exercises does not affect the increase in 1-RM in bench press and bench triceps extension. L. Brandão et al. [22] argued that performing these exercises in any sequence is effective for achieving maximum strength. There was a moderate decrease in CSA increase in the pectoralis major when an isolated triceps exercise was performed before a multi-joint exercise. ...
The systematic review aimed to determine the effect of strength training on physiological and morphological adaptive capacities in healthy young men. A search was conducted for randomised clinical trials containing information on the effect of resistance exercise on physical and functional changes in young men aged 18-45 years. As a result, 13 publications that met the search criteria were found, of which 9 studies were selected after excluding inappropriate ones. Most of the studies were assessed as good-quality research with a score of 7-9 on the PEDro scale. Long-term strength training has been shown to significantly improve strength, muscle volume and explosive abilities in trained individuals. Strength training 3 times a week can increase lean body mass and left ventricular mass index, with a decrease in body fat. Light training stimulates hypertrophy of the gastrocnemius muscle more than heavy training, which has a greater impact on the middle and lateral heads of the gastrocnemius muscle. The sequence of exercises does not affect the increase in maximum strength, but the effect on pectoral muscle hypertrophy may be better when performing multi-joint exercises after isolated exercises. The appearance of microRNAs does not show specificity in the early acute state of training, with changes in expression observed 8 hours after training. The duration of weightlifting training has a positive effect on anthropometric and physiological parameters, but not on biochemical parameters
... , Brandão et al.55 e Spineti et al.57 , encontramos diferenças na hipertrofia muscular com a mudança na ordem dos exercícios (a partir da alteração de iniciar com monoarticulares e posteriormente realizar multiarticulares) durante as sessões de treinamento, no entanto, o volume não foi equacionado nas diferentes condições, fator que pode ter influenciado estes resultados. Nunes et al.72 analisaram 11 estudos de qualidade boa ou excelente em uma revisão sistemática, em concordância com Simão et al. 59 , os achados não indicaram diferença na ordem dos exercícios em relação a hipertrofia muscular, porém, exercícios realizados primeiramente em uma sessão de treinamento podem Brazilian Journal of Science and Movement. ...
As recomendações para o treinamento resistido partem de diretrizes como o ACSM e NSCA para as populações em geral, sendo encorajado a sua prática, a qual leva a benefícios à saúde física e mental. Nessa revisão narrativa, foi analisada a literatura atual sobre as variáveis do treinamento resistido (TR) e sua relação com a hipertrofia muscular, primeiramente, abordando os resultados acerca de cada variável de maneira isolada, posteriormente discutindo os resultados com revisões sistemáticas sobre cada variável isoladamente, e por último, chegando a um consenso do papel de cada variável como um conjunto, e seu impacto na hipertrofia muscular. Em nossos achados encontramos uma relação do volume com a hipertrofia, a frequência como ferramenta para distribuição do volume, um amplo espectro de intensidades que resultam em resultados equivalentes, a ordem e seleção dos exercícios como recurso para hipertrofia localizada, ações excêntricas superiores a ações concêntricas, intervalos como uma maneira de aumentar o volume, e a amplitude de movimento permanece necessitando de mais estudos para relacionar seu papel com a hipertrofia muscular.
... However, hypertrophy-oriented training did not produce muscle growth. Although it has been shown that low-and high-load resistance training [17][18][19][20][21][22], and singleand multi-joint exercises [23][24][25] promote muscle growth in untrained individuals, it is possible that the combination of low load (40% of 1RM) and type of exercise (multi-joint) blunted muscle growth in a specific region of the muscle. This idea is supported by the results observed by Holm et al. [26] who observed similar hypertrophy of the quadriceps in the distal and proximal portion for high (70% of 1RM) and low load (15.5% of 1RM) resistance training, while only high load training produced significant hypertrophy in the medial portion. ...
Background
The objective of this study was to test if resistance training induced muscle hypertrophy leads to greater strength gains.
Methods
Nine untrained men had their upper limbs randomly divided into two conditions: hypertrophy + strength (HST) and strength (ST) training. Participants trained twice a week for 10 weeks. HST-arm performed a hypertrophy-oriented training protocol for 6 weeks and then a 4-week strength-oriented training; while ST-arm did not train during the initial 6 weeks and performed the 4-week strength-oriented training. Hypertrophy-oriented training consisted in 3 sets at 40% of 1RM until failure in the unilateral pull-down exercise, and strength-oriented training consisted of 3 sets of five 5-s maximal elbow flexion isometric contraction. Muscle thickness, 1RM and maximal voluntary isometric contraction (MVIC) were assessed before (pre), after 6 weeks (mid) and at the end of the 10-week (post) training period.
Results
Muscle thickness and 1RM did not change in both arms (P > 0.05). However, HST was the only condition that elicited a change in MVIC (P = 0.03). Although no changes in muscle size was observed, only the group that performed the hypertrophy-oriented training increased strength during the strength-oriented period.
Conclusions
Although we did not find differences in strength increase between the experimental conditions, we speculate that it may be interesting to include a period of hypertrophy-oriented training before strength-oriented training, as we have reported increased strength in this condition.
... The present investigation has some issues to be addressed. First, although dual-energy x-ray absorptiometry is well established as a valid instrument to assess the effects of RT on hypertrophy, the use of regionalized measures of muscle growth (e.g., cross-sectional area via magnetic resonance imaging) could contribute to the exploration of the effects of exercise order on specifically trained muscles and muscle regions separately, especially given that different exercises may promote effects in different muscle regions (46). Second, we did not control habitual physical activity levels outside the investigation environment, which may have confounded the results. ...
... The present investigation has some issues to be addressed. First, although dual-energy x-ray absorptiometry is well established as a valid instrument to assess the effects of RT on hypertrophy, the use of regionalized measures of muscle growth (e.g., cross-sectional area via magnetic resonance imaging) could contribute to the exploration of the effects of exercise order on specifically trained muscles and muscle regions separately, especially given that different exercises may promote effects in different muscle regions (46). Second, we did not control habitual physical activity levels outside the investigation environment, which may have confounded the results. ...
Purpose:
To compare the effects of four resistance exercise orders on muscular strength, body composition, functional fitness, cardiovascular risk factors, and mental health parameters in trained older women.
Methods:
The intervention lasted 63 weeks. Sixty-one physically independent women (> 60 years) after completing a 12-week resistance training (RT) pre-conditioning phase were randomized into four different exercise orders groups to perform 12 weeks of RT: multi- to single-joint and upper- to lower-body (MJ-SJ-U), single- to multi-joint and upper- to lower-body (SJ-MJ-U), multi- to single-joint and lower- to upper-body (MJ-SJ-L), and single- to multi-joint and lower- to upper-body (SJ-MJ-L). This was followed by a 12-week detraining period and another 12-week RT in which exercise orders were crossed-over between MJ-SJ and SJ-MJ conditions. Body composition (DXA), muscular strength (1RM tests), functional fitness (gait speed, walking agility, 30-s chair stand, and 6-min walk tests), cardiovascular risk factors (glucose, triglycerides, total cholesterol, LDL-c, HDL-c, C-reactive protein, AOPP, TRAP, and NOx), depressive (GDS-scale), and anxiety symptoms (BAI), cognitive performance (MoCA, Trail Making, verbal fluency, and Stroop test) were analyzed.
Results:
Following the final training period, all groups presented significant improvements (P < 0.05) in almost all analyzed variables (muscular strength, body composition, functional tests, blood biomarkers, and mental health parameters), without significant difference among exercise orders.
Conclusions:
Our results suggest that RT exercise orders in which MJ, SJ, upper, or lower-body exercises are performed first have similar effects on health parameters in trained older women.
... The order of the exercises follows the mass principle: first the bigger muscle masses, and then the smaller. Since the order of the exercises influences the perception of fatigue, it is better to perform the more fatiguing exercises first [43,44]. Therefore, legs are normally the first to be trained, followed by the upper limbs, and then the abdominal and trunk muscles. ...
This systematic integrative review aims to summarize the protective effect of PA on children and adolescents, with special reference to the immune system. Periods of prolonged inactivity in children and adolescents are rare and due to exceptional events, such as illness or environmental circumstances, e.g., natural disasters, wars, or epidemics. The recent COVID-19 pandemic forced billions of children in developmental ages into inactivity. This exceptional event was the reason for studying the compensational behavioral strategies adopted by children and adolescents to counteract physical inactivity. Several studies showed the rise of spontaneous physical activity (PA) among children and adolescents to compensate for sedentarism. However, for some children, sedentarism could in turn foster other sedentarism. With the restart of “normal daily life” worldwide, a question is posed on both how to resume PA without causing damage and how to improve the immune response. Some key points emerged from the literature. Children must resume PA gradually using different methods, considering age, sex, health status, and the presence of overweight conditions. Immunity can be stimulated with PA by aerobic exercise, resistance training, flexibility exercise, relaxation, and coordinative exercises.
... Bench press exercise is known to activate PM, TB and AD muscles (e.g., Stastny et al., 2017). Previous studies in men have observed greater strength training-induced muscle hypertrophy in PM than in TB muscles (Brandão et al., 2020) as also observed in the present female ECC and CON groups. The current findings regarding larger hypertrophy of the upper extremities in women using ECC vs. CON strength training are unique. ...
Effects of eccentric (ECC) versus concentric (CON) strength training of the upper body performed twice a week for 10 weeks followed by detraining for five weeks on maximal force, muscle activation, muscle mass and serum hormone concentrations were investigated in young women (n = 11 and n = 12). One-repetition bench press (1RM), maximal isometric force and surface electromyography (EMG) of triceps brachii (TB), anterior deltoid (AD) and pectoralis major (PM), cross-sectional area (CSA) of TB (Long (LoH) and Lateral Head (LaH)) and thickness of PM, as well as serum concentrations of free testosterone, cortisol, follicle-stimulating hormone, estradiol and sex hormone-binding globulin were measured. ECC and CON training led to increases of 17.2 ± 11.3% (p < 0.001) and 13.1 ± 5.7% (p < 0.001) in 1RM followed by decreases of -6.6 ± 3.6% (p < 0.01) and -8.0 ± 4.5% (p < 0.001) during detraining, respectively. Isometric force increased in ECC by 11.4 ± 9.6 % (p < 0.05) from week 5 to 10, while the change in CON by 3.9±6.8% was not significant and a between group difference was noted (p < 0.05). Maximal total integrated EMG of trained muscles increased only in the whole subject group (p < 0.05). CSA of TB (LoH) increased in ECC by 8.7 ± 8.0% (p < 0.001) and in CON by 3.4 ± 1.6% (p < 0.01) and differed between groups (p < 0.05), and CSA of TB (LaH) in ECC by 15.7 ± 8.0% (p < 0.001) and CON by 9.7 ± 6.6% (p < 0.001). PM thickness increased in ECC by 17.7 ± 10.9% (p < 0.001) and CON by 14.0 ± 5.9% (p < 0.001). Total muscle sum value (LoH + LaH + PM) increased in ECC by 12.4 ± 6.9% (p < 0.001) and in CON by 7.1 ± 2.9% (p < 0.001) differing between groups (p < 0.05) and decreased during detraining in ECC by -6.5 ± 4.3% (p < 0.001) and CON by -6.1 ± 2.8% (p < 0.001). The post detraining combined sum value of CSA and thickness was in ECC higher (p < 0.05) than at pre training. No changes were detected in serum hormone concentrations, but baseline free testosterone levels in the ECC and CON group combined correlated with changes in 1RM (r = 0.520, p < 0.016) during training. Large neuromuscular adaptations of the upper body occurred in women during ECC, and CON training in 10 weeks. Isometric force increased only in response to ECC, and total muscle sum value increased more during ECC than CON training. However, no changes occurred in serum hormones, but individual serum-free testosterone baseline concentrations correlated with changes in 1RM during strength training in the entire group. Both groups showed significant decreases in neuromuscular performance and muscle mass during detraining, while post detraining muscle sum value was only in ECC significantly higher than at pre training.
... Combining multi-and single-joint exercise appears to confer a synergistic effect to foster complete development of the musculature. Brandao et al. (153) found that performance of the bench press (multi-joint exercise) led to the greatest increase in cross-sectional area of the lateral head of the triceps brachii whereas performance of the lying triceps extension (single-joint exercise) elicited the greatest increase in the long head over a 10-week training period; the combination of the single-and multi-joint exercises produced the greatest overall increase in cross-sectional area of the triceps brachii as a whole. Similar conclusions can be inferred indirectly from the literature for the thigh musculature. ...
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.
... Therefore, classic resistance training periodization is not always strictly observed, and specific biomechanical strategies are employed, albeit empirically, to obtain hypertrophic responses from specific muscle groups. In fact, the indiscriminate gain in muscle volume does not seem interesting for this population, given that intra and intermuscular hypertrophy responds differently to different exercise modalities [37][38][39][40]. ...
Bodybuilding is a sport that requires adequate training strategies in order to maximize skeletal muscle hypertrophy. The purpose of the present review was to perform a narrative assessment of the training routines designed for muscle hypertrophy used by bodybuilders. A search was carried out in the databases Pubmed/MEDLINE, Scielo, EBSCO, LILACS, SportDiscus, Web of Science, and CINAHL with the words "Resistance training" and "hypertrophy" in bodybuilders and their variations that involve the respective outcomes. Fourteen studies were identified that investigated the long-term training routines of bodybuilders. These studies demonstrate a pattern in the training organization, whereby there is a separation of training into four distinct periods: off-season, pre-contest, peak week, and post-contest. Each period has a specific spectrum of intensity load, total training volume, and exercise type (multi-or single-joint). We conclude that bodybuilding competitors employed a higher intensity load, lower number of repetitions, and longer rest intervals in the off-season than pre-contest.
... For muscular strength, responses are directly dependent on the task practiced [4,5]. That is, regardless of the specific training variable manipulated, more significant performance increases tend to be observed when the strength tests are similar to the exercise task and intensity of load employed during training [5][6][7][8]. For example, the benefit of traditional linear periodization programs for improving one-repetition maximum strength seems to be because participants train with higher loads during sessions near post-training evaluation [4]. ...
Muscular strength and hypertrophy following resistance training may be obtained in different degrees depending on the approach performed. This study was designed to compare the responses of the biceps brachii to two preacher curl exercises, one performed on a cable-pulley system (CAB; in which a greater torque was applied during the exercise when elbows were flexed and biceps shortened) and one performed with a barbell (BAR; in which greater torque was applied when the elbows were extended and biceps stretched). Thirty-five young adults (CAB: 13 men, 5 women; BAR: 12 men, 5 women; age = 24 ± 5 years) performed a resistance training program three times per week for 10 weeks, with preacher curl exercises performed in 3 sets of 8-12 repetitions. Outcomes measured included elbow flexion peak isokinetic torque at angles 20°, 60°, and 100° (considering 0° as elbow extended), and biceps brachii thickness (B-mode ultrasound). Following training period, there were observed significant increases for both groups in elbow flexion peak torque at the 20° (CAB: 30%; BAR = 39%; P = 0.046), 60° (CAB: 27%; BAR = 32%; P = 0.874), and 100° (CAB: 17%; BAR = 19%; P = 0.728), and biceps brachii thickness (CAB: 7%; BAR = 8%; P = 0.346). In conclusion, gains in muscular strength were greater for BAR only at longer muscle length, whereas hypertrophy was similar regardless if torque emphasis was carried out in final (CAB) or initial (BAR) degrees of the range of motion of preacher curl in young adults.
Sportif performansın ve yaşam kalitesinin artırılmasında önemli bir role sahip olan kas kuvvetini geliştirmek için birçok farklı yöntem uygulanmaktadır. Bu doğrultuda antrenman programları oluşturulurken, fizyolojik adaptasyonları sağlamak ve dolayısıyla en iyi performansı elde etmek için birçok değişken göz önünde bulundurulmakta ve yeni antrenman yöntemleri denenmektedir. Kan akışı kısıtlama yöntemi (KAK) ise geleneksel yöntemlere alternatif yöntem olarak son yıllarda antrenman seanslarına sıklıkla dahil edilen bir yöntem haline gelmiştir. Özellikle uluslararası literatürde kullanımı yaygın olan bu yöntem ile ilgili farklı protokollerde birçok parametre üzerine incelemeler gerçekleştirilmektedir. Tüm bu bilgiler ışığında yapılan derlemenin amacı uluslararası literatürde yaygın olarak araştırma konusu yapılan KAK yönteminin ana hatlarıyla tanıtılması ve bu konuda Türk yazarlı olarak yapılan çalışmaların KAK yönteminde uygulanan değişkenler yönünden incelenmesidir. Çalışmada PubMed, Google Scholar, Web of Science, Yöktez veri tabanlarında “kan akışı kısıtlama”, “kan akımı kısıtlama”, “blood flow restriction”, “blood flow restriction*training”, “occlusion training” “kaatsu*occlusion training”, “kaatsu*blood flow restriction” arama terimleri ile taramalar gerçekleştirilmiştir. Belirlenen çalışmalar katılımcı sayıları, yaş aralığı, manşon tipi, manşon genişliği, basınç yöntemi, egzersiz şiddeti, tekrar sayısı, sıklık, hareketin yapısı, kombine edildiği egzersiz türü, kullanılan materyaller ve ölçüm yöntemleri gibi değişkenler yönünden incelenmiştir. Sonuç olarak, yapılan derleme ile uluslararası literatürde kullanımı yaygın olan KAK yönteminin ulusal literatürde de kullanılmasına olanak sağlanacağı ve gelecekte yapılacak Türk yazarlı çalışmalarda metot kurgusunun daha güvenilir ve anlaşılır düzeyde oluşturulmasında rehber olacağı düşünülmektedir.
Sportif performansın ve yaşam kalitesinin artırılmasında önemli bir role sahip olan kas kuvvetini geliştirmek için birçok farklı yöntem uygulanmaktadır. Bu doğrultuda antrenman programları oluşturulurken, fizyolojik adaptasyonları sağlamak ve dolayısıyla en iyi performansı elde etmek için birçok değişken göz önünde bulundurulmakta ve yeni antrenman yöntemleri denenmektedir. Kan akışı kısıtlama yöntemi (KAK) ise geleneksel yöntemlere alternatif yöntem olarak son yıllarda antrenman seanslarına sıklıkla dahil edilen bir yöntem haline gelmiştir. Özellikle uluslararası literatürde kullanımı yaygın olan bu yöntem ile ilgili farklı protokollerde birçok parametre üzerine incelemeler gerçekleştirilmektedir. Tüm bu bilgiler ışığında yapılan derlemenin amacı uluslararası literatürde yaygın olarak araştırma konusu yapılan KAK yönteminin ana hatlarıyla tanıtılması ve bu konuda Türk yazarlı olarak yapılan çalışmaların KAK yönteminde uygulanan değişkenler yönünden incelenmesidir. Çalışmada PubMed, Google Scholar, Web of Science, Yöktez veri tabanlarında “kan akışı kısıtlama”, “kan akımı kısıtlama”, “blood flow restriction”, “blood flow restriction*training”, “occlusion training” “kaatsu*occlusion training”, “kaatsu*blood flow restriction” arama terimleri ile taramalar gerçekleştirilmiştir. Belirlenen çalışmalar katılımcı sayıları, yaş aralığı, manşon tipi, manşon genişliği, basınç yöntemi, egzersiz şiddeti, tekrar sayısı, sıklık, hareketin yapısı, kombine edildiği egzersiz türü, kullanılan materyaller ve ölçüm yöntemleri gibi değişkenler yönünden incelenmiştir. Sonuç olarak, yapılan derleme ile uluslararası literatürde kullanımı yaygın olan KAK yönteminin ulusal literatürde de kullanılmasına olanak sağlanacağı ve gelecekte yapılacak Türk yazarlı çalışmalarda metot kurgusunun daha güvenilir ve anlaşılır düzeyde oluşturulmasında rehber olacağı düşünülmektedir.
Different methods can be used to assess muscle hypertrophy, but the effects of training on regional changes in muscle size can be detected only using direct muscle measurementssuch as muscle thickness, cross-sectional area, or volume. Importantly, muscle size increases vary across regions both within and between muscles following resistance training programs (i.e., heterogeneous, or non-uniform, muscle hypertrophy). Muscle architectural changes, including fascicle length and pennation angle, following resistance and stretch training programs are also region-specific. In the present paper, we show that the literature indicates that a single-site measure of muscle shape does not properly capture the effects achieved following exercise training interventions and that conclusions concerning the magnitude of muscle adaptations can vary substantially depending on the muscle site to be examined. Thus, we propose that measurements of muscle size and architecture should be completed at multiple sites across regions both between the agonist muscles within a muscle group and along the length of the muscles to provide an adequate picture of training effects.
Introduction
Taekwondo is a sport of highly competitive intensity, and the gain in physical fitness of its practitioners is a work that involves analysis of combat techniques, sports biomechanics, and theories of physical training. However, studies of current methods, such as explosive strength training, are still superficial.
Objective
Study the effect of different explosive strength training protocols on the lower limbs of taekwondo athletes.
Methods
24 taekwondo athletes were randomly selected as volunteers and divided into experimental and control groups. These were subdivided to perform traditional and different strength training combinations. The experiment lasted eight weeks, with the first four weeks dedicated to strength training adaptation. Data on body shape, maximal strength, explosive strength, and fitness were collected for statistical comparison.
Results
Through repeated measures analysis of variance to test lower limb explosive strength on exercise level, it can be seen that there is a significant difference between the test data before and after the approach (P<0.05), this difference was not observed in the control group (P>0.05). The mean value of all indexes in the experimental group was higher than in the control group.
Conclusion
Explosive strength training and its different combinations on lower limbs can significantly improve the physical fitness of taekwondo athletes. The different combinations of strength training presented can be used as an effective resource in the lower limbs athletes’ explosive strength gain. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.
Keywords:
Training, Strength; Lower Limbs; Martial Arts
Introduction
In track and field events, the force generated by running, jumping, and throwing starts from the lower limbs and is transmitted from bottom to top, forming a complete dynamic chain.
Objective
Study the effect of different combined strength training methods on the explosive strength of the lower limbs of track and field athletes.
Methods
Twenty members of the track and field team were selected as research subjects and divided into two groups, A and B. Group A performed the maximum resistance training method, and group B performed the submaximal resistance training method and underwent 12 weeks of different combined strength training.
Results
After 12 weeks of training, there was a significant difference in the results of the two groups of students in the approach run (male P=0.034, female P=0.021), and the results of experimental group B improved significantly.
Conclusion
The maximum resistance training method can most effectively improve the explosive performance of the lower limbs of track and field practitioners. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.
Keywords:
Athletes; Strength Training; Lower Limbs
Resistance exercise range of motion (ROM) influences muscular adaptations. However, there are no consistent practical guidelines about the optimal ROM for maximizing muscle hypertrophy. The objective of the present paper was to systematically review the literature for studies that compared the effects of full ROM (fROM) and partial ROM (pROM) on muscle hypertrophy. PubMed/MEDLINE, Scopus, and Web of Science databases were searched to identify articles from the earliest record up to and including April 2022. We calculated the effect size (ES) scores of the variables of interest. Eleven studies were included in the review. fROM and pROM performed in the initial part of the ROM elicited greater muscle hypertrophy of the rectus femoris, vastus lateralis, biceps brachii and brachialis distal sites (between-groups ES: 0.20–0.90) than pROM performed in the final part of the ROM. fROM elicited greater muscle growth on the gluteus maximus and adductors than pROM in the final part of the ROM (between-groups ES: 0.24–0.25). Initial pROM produced more favorable proximal rectus femoris hypertrophy than fROM (between-group ES: 0.35–0.38). pROM in the middle part of the ROM elicited greater triceps brachii hypertrophy than fROM (between-groups ES: 1.21). In conclusion, evidence suggests that when training at a longer muscle length—through either a pROM or fROM—some muscles, such as the quadriceps femoris, biceps brachii and triceps brachii tend to experience optimal growth. Thus, the use pROM in the initial part of the excursion in combination with fROM training should be considered when prescribing hypertrophy-oriented resistance training programs.
Fitness professionals routinely employ a variety of resistance training exercises in program design as a strategy to enhance muscular adaptations. However, it remains uncertain whether such an approach offers advantages over a fixed-exercise selection. The objective of this paper was to review the effects of exercise variation on muscle hypertrophy and strength. A search of literature was conducted using PubMed/MEDLINE, Scopus, and Web of Science databases. Eight studies were identified as meeting inclusion criteria. The combined total sample of the studies was n = 241, comprising all young men. The methodological quality of included studies was considered "good" and "excellent" based on the PEDro Scale. The available studies indicate that varying exercise selection can influence muscle hypertrophy and strength gains. Some degree of systematic variation appears to enhance regional hypertrophic adaptations, and maximize dynamic strength, whereas excessive, random variation may compromise muscular gains. We conclude that exercise variation should be approached systematically with a focus on applied anatomical and biomechanical constructs; on the contrary, employing different exercises that provide a redundant stimulus, as well as excessive rotation of different exercises (i.e., high frequency of change), may actually hinder muscular adaptations.
Over time, complex interactions and a nonlinear progression among a wide range of variables contribute to improvements in the physical health and level of achievement in youth sports practitioners. Various elements, including technical skills, physical performance, environmental circumstances, and social conditioning, contribute to the development of these processes.
An influencing factor of growth and physical performance is somatic maturation. The pubertal period is a critical time for skill acquisition and improvements in performance for young people, in which suitable training strategies should be adopted to preserve their state of health while avoiding risks of injury. Athletes with similar chronological ages competing in the same category levels can, in fact, show differences in maturity and, therefore, in size, function, and body structure. Physical and psychological differences related to maturity and birthdate amongst athletes of the same selection year have been identified in a variety of sports and could be linked with the dropout of youth practitioners and a reduction in the talent pool.
Contemporary researchers have contributed to research on improving health and sports performance through the development of new measurement methods and training strategies in young athletes. The aim of this Special Issue of , entitled , Somatic Maturation, and Their Impact on Physical Health and Sports Performance, is to propose and evaluate new training strategies aimed at improving the health status and physical performance of young athletes while highlighting the relationship between somatic maturation, anthropometry features, education, and health-related factors via longitudinal and cross-sectional studies.
Background:
Cross-education of strength refers to the strength gain that is transferred to the contralateral limb after a unilateral training program.
Hypothesis:
Unilateral eccentric training using different muscle contraction times would improve the structural and functional properties of the untrained contralateral limb.
Study design:
Randomized controlled trial.
Level of evidence:
Level 2.
Methods:
Thirty-six participants were randomized into a control group, experimental group 1 (EG6s; eccentric contraction runtime = 6 seconds) and experimental group 2 (EG3s; eccentric contraction runtime = 3 seconds). The thickness and elastographic index of the patellar tendon (PT), lean mass and fat percentage of the thigh, contractile properties of the vastus lateralis (VL), as well as isometric, concentric, and eccentric knee extensor peak torques, and eccentric single-leg decline squat (SLDSe) 1 repetition maximum (1-RM) were measured after 6 weeks of SLDSe training (3 times per week, 80% of 1-RM) and after 6 weeks of detraining in the untrained contralateral limb.
Results:
After training, there was an increase in lean thigh mass of the untrained limb in both groups: EG6s (0.17 ± 0.29 kg;P = 0.03; effect size [ES] = 0.15) and EG3s (0.15 ± 0.23 kg; P = 0.04; ES = 0.19). Likewise, both EG6s (62.30 ± 19.09 kg; P < 0.001; ES = 4.23) and EG3s (68.09 ± 27.49 kg; P < 0.001; ES = 3.40) increased their 1-RM, isometric (EG6s: 48.64 ± 44.82 N·m, P < 0.001, ES = 0.63; EG3s: 34.81 ± 47.30 N·m, P = 0.004, ES = 0.38), concentric at 60 deg/s and 180 deg/s and eccentric at 60 deg/s and 180 deg/s knee extensor peak torques (P < 0.05) in the untrained limb. However, no differences were found in the contractile properties of the VL or in the thickness of the PT after eccentric training in either of the 2 experimental groups.
Conclusion:
Regardless of the runtime of the contraction, 6 weeks of SLSDe was effective for inducing structural and strength adaptations in the contralateral untrained limb. However, most of these adaptations were lost after 6 weeks of detraining.
Clinical relevance:
Our study suggests that cross-education training can be of great importance for clinical application and musculoskeletal and neuromuscular rehabilitative processes after unilateral injury.
Mannarino, P, Matta, T, Lima, J, Simão, R, and Freitas de Salles, B. Single-Joint Exercise Results in Higher Hypertrophy of Elbow Flexors Than Multijoint Exercise. J Strength Cond Res XX(X): 000-000, 2019-Recent data suggest that single-joint exercises are unnecessary to maximize the resistance training (RT) results in novice to advanced individuals. However, the present literature is still inconsistent on this topic and controversy arises. The aim of this study was to compare the effects of the unilateral dumbbell row (DR) (multiple-joint) vs. unilateral biceps curl (BC) (single-joint) exercises on strength and elbow flexors muscle thickness (MT). Ten untrained men were assigned to an 8-week RT program for elbow flexors, one arm performing DR and the other performing BC in a within-subject design. After a familiarization, pretraining MT was measured using an ultrasound (US) technique, and strength was tested using 10 repetition maximum (10RM) tests. After pretesting, 8 weeks of RT (4-6 sets, 8-12 repetitions to concentric failure, 2 sessions per week) was performed. Post-testing was conducted in the same order as pretesting 48 and 72 hours after the last session. Single-joint BC exercise resulted in higher hypertrophy of elbow flexors (11.06%) than the DR (5.16%) multijoint exercise after 8 weeks of RT (p = 0.009). The 10RM improvement was higher for DR in DR-trained arm, whereas 10RM for BC was higher in BC-trained arm. The single-joint exercise resulted in higher hypertrophy of the elbow flexors than multijoint exercise after 8 weeks of RT, whereas strength improvements were greater in accordance with specificity of RT exercise. Therefore, in RT prescription for elbow flexors hypertrophy, single-joint exercises such as BC should be emphasized.
We, the Editor‐in‐Chief and Publishers of the European Journal of Sport Science, retract the following article:
Matheus Barbalho, Victor Coswig, Rodolfo Raiol, James Fisher, James Steele, Antonino Bianco, Paulo Gentil, ‘Single joint exercises do not provide benefits in performance and anthropometric changes in recreational bodybuilders’, European Journal of Sport Science, 20:1, 72‐79, DOI: 10.1080/17461391.2019.1611932
Two authors of the original article (James Fisher, and James Steele) raised questions regarding the data integrity and requested that it be retracted. Following data concerns raised in the published White Paper below, an external statistical review was undertaken.
Vigotsky, A. D., Nuckols, G. L., Fisher, J., Heathers, J., Krieger, J., Schoenfeld, B. J., Giessing, J., Steele, J. (2020, July 18). Improbable data patterns in the work of Barbalho et al. https://doi.org/10.31236/osf.io/sg3wm
The White Paper includes two authors who are also co‐authors of the above paper by Barbalho et al., published in the European Journal of Sport Science (James Fisher, and James Steele). We informed all of the authors, as well as the first author's institution, about these concerns, and invited them to respond. Having considered the evaluation report from the external review, as well as author and institutional responses, we find the data and findings in the article to be unreliable and invalid.
All authors have been informed of our decision to retract this article. The authors James Fisher, James Steele, and Antonino Bianco wish to record their agreement with the decision to retract to be noted within this retraction statement.
We have been informed in our decision‐making by our policy on publishing ethics and integrity and the guidance of COPE guidelines on retractions .
The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.
Background: The present study's aim was to compare the changes in muscle performance and anthropometric measures in trained women performing RT programs composed only of MJ exercises or programmes that involve the addition of SJ exercises. Methods: Seventeen trained women were randomised to MJ or MJ+SJ. Both groups performed the same MJ exercises following a nonlinear periodisation model for 8 weeks. The only difference was that the MJ+SJ group also performed SJ exercises. The participants were tested for 10 repetition maximum (10 RM), flexed arm circumference, and both biceps and triceps skinfold. Results: Both groups significantly increased 10 RM load for the bench press (12.6% MJ and 9.2% MJ+SJ), triceps (15.6% MJ and 17.9% MJ+SJ), pull down (9.8% MJ and 8.3% MJ+SJ), biceps (14.0% MJ and 13.0% MJ+SJ), leg press (15.2% MJ and 12.8% MJ+SJ) and knee extension (10.2% MJ and 9.1% MJ+SJ). The decreases in triceps (−5.1% MJ and −5.3% MJ+SJ) and biceps (−6.5% MJ and −5.7% MJ+SJ) skinfolds were also significant as were the increases in arm circumference (1.47% MJ and 1.58% MJ+SJ). In all tests there was nothing significantly different between groups. Conclusions: The use of SJ exercises as a complement to a RT programme containing MJ exercises brings no additional benefit to trained women.
The present study compared changes in muscle performance and anthropometric measures in young men performing resistance training (RT) programs composed of only multi joint (MJ) exercises, or with the addition of single joint (SJ) exercises (MJ+SJ). Twenty untrained men were randomized to MJ or MJ+SJ groups for 8 weeks. Both groups performed the same MJ exercises. The difference was that the MJ+SJ group added SJ exercises for upper and lower limbs. Participants were tested for 10 repetitions maximum (10RM), flexed arm circumference, and biceps and triceps skinfolds. Both groups significantly increased 10RM load for the bench press (MJ 38.5%, MJ+SJ 40.1%), elbow extension (MJ 28.7%, MJ+SJ 31.9%), pull down (MJ 34.0% MJ+SJ 38.5%), elbow flexion (MJ 38.2%, MJ+SJ 45.3%), leg press (MJ 40.8%, MJ+SJ 46.8%) and knee extension (MJ 26.9%, MJ+SJ 32.9%), with no significant difference between them. The decreases in biceps (MJ-3.6%, MJ+SJ-3.9%) and triceps (MJ-3.4%, MJ+SJ-3.3%) skinfolds were significant for both groups, with no difference between them. However, the flexed arm circumference increased significantly more for MJ+SJ (5.2%), than for MJ (4.0%). The use of SJ exercises as a complement to a RT program containing MJ exercises brings no additional benefit to untrained men in terms of muscle performance and skinfold reduction, though it promoted higher increases in arm circumference.
The purpose of the present study was to analyze the effects of the order of resistance training (RT) exercises on hypertrophy in young adult men. Thirty-six young adult men (age, 21.9 ± 2.5 years; body mass, 72.6 ± 12.1 kg, height, 176.9 ± 7.4 cm; body mass index, 23.1 ± 3.3 kg/m²) were randomly assigned to 1 of 2 training groups that performed a 6-week RT program in either (i) a traditional approach starting with multi-joint (MJ) exercises followed by single-joint exercises (SJ) (MJ-SJ, n = 19) or (ii) in reverse order (SJ-MJ, n = 17). Muscle thickness of the biceps brachii and mid-thigh were assessed by ultrasound. Lean soft tissue (LST) was assessed by dual-energy X-ray absorptiometry. Both groups similarly increased (P < 0.05) biceps brachii thickness (MJ-SJ = +14.2%, SJ-MJ = +13.8%). Alternatively, only the MJ-SJ group presented an increase in mid-thigh thickness from pre- to post-training (MJ-SJ = +7.2%, SJ-MJ = +3.9%). Upper limb LSTs (MJ-SJ = +5.2%, SJ-MJ = +7.5%) were statistically similar between conditions, and a trend for significance (P = 0.07) was found for trunk LST (MJ-SJ = +7.2%, SJ-MJ = +1.7%). Nonsignificant pre- to post-training changes were observed for lower limb LSTs (MJ-SJ = +0.7%, SJ-MJ = +1.8%). Our data suggest that both sequences are effective for increasing muscle hypertrophy over a short-term RT period; there may be a potentially beneficial hypertrophic effect for the mid-thigh by performing exercises in a manner that progresses from MJ to SJ exercises.
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.
The pre-exhaustion (PE) system in resistance training is largely used by athletes and practitioners with the goal of enhancing muscular adaptations. PE consists of performing a single-joint exercise prior to a multiple-joint exercise in an effort to increase the overload (muscle activation and/or training volume) in a given muscle. Different PE approaches have been investigated in research; this review discusses the relevant literature regarding the efficacy of PE for potentiating overload and muscle hypertrophy. In general, PE does not alter the neuromuscular activity of the target muscle in multi-joint exercise, but it does allow for a greater training volume.
Barbalho, M, Gentil, P, Raiol, R, Fisher, J, Steele, J, and Coswig, V. Influence of adding single-joint exercise to a multijoint resistance training program in untrained young women. J Strength Cond Res XX(X): 000-000, 2018-The aim of the present study was to investigate the effects of adding single-joint (SJ) exercises to a multijoint (MJ) resistance training (RT) program on muscle strength and anthropometric measures of young women. Twenty untrained women were divided into a group that performed only MJ exercises or a group that performed both SJ and MJ exercises (MJ + SJ). Before and after 8 weeks of training, the participants were tested for 10 repetition maximum (10RM). Flexed arm circumference and triceps and biceps skinfold thickness were also measured. Both groups significantly decreased biceps (-3.60% for MJ and -3.55% for MJ + SJ) and triceps skinfold (-3.05% for MJ and -2.98% for MJ + SJ), with no significant difference between them. Flexed arm circumference significantly increased in both groups; however, increases in MJ + SJ (4.39%) were significantly greater than MJ (3.50%). Increases in 10RM load in elbow extension (28.2% for MJ and 28.0% for MJ + SJ), elbow flexion (29.8% for MJ and 28.7% for MJ + SJ), and knee extension (26.92% for MJ and 23.86% for MJ + SJ) were all significant and not different between groups. The results showed that adding SJ exercises to an MJ RT program resulted in no benefits in muscle performance or anthropometric changes in untrained women.
The present study investigated the effects of different intensities of resistance training (RT) on elbow flexion and leg press one-repetition maximum (1RM) and muscle cross-sectional area (CSA). Thirty men volunteered to participate in an RT programme, performed twice a week for 12 weeks. The study employed a within-subject design, in which one leg and arm trained at 20% 1RM (G20) and the contralateral limb was randomly assigned to one of the three conditions: 40% (G40); 60% (G60), and 80% 1RM (G80). The G20 started RT session with three sets to failure. After G20 training, the number of sets was adjusted for the other contralateral limb conditions with volume-matched. CSA and 1RM were assessed at pre, post-6 weeks, and post-12 weeks. There was time effect for CSA for the vastus lateralis (VL) (8.9%, 20.5%, 20.4%, and 19.5%) and elbow flexors (EF) (11.4%, 25.3%, 25.1%, and 25%) in G20, G40, G60, and G80, respectively (p > .05). G80 showed higher CSA than G20 for VL (19.5% vs. 8.9%) and EF (25% vs. 11.4%) at post-12 weeks (p < .05). There was time effect for elbow flexion and unilateral leg press strength for all groups post-12 weeks (p < .05). However, the magnitude of increase was higher in G60 and G80. In conclusion, when low to high intensities of RT are performed with volume-matched, all intensities were effective for increasing muscle strength and size; however, 20% 1RM was suboptimal in this regard, and only the heavier RT intensity (80% 1RM) was shown superior for increasing strength and CSA compared to low intensities.
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 study aimed to compare the effects of equal-volume resistance training performed with single-joint (SJ) or multi-joint exercises (MJ) on VO2max, muscle strength and body composition in physically active males. Thirty-six participants were divided in two groups: SJ group (n = 18, 182.1 ± 5.2, 80.03 ± 2.78 kg, 23.5 ± 2.7 years) exercised with only SJ exercises (e.g., dumbbell fly, knee extension, etc.) and MJ group (n = 18, 185.3 ± 3.6 cm, 80.69 ± 2.98 kg, 25.5 ± 3.8 years) with only MJ exercises (e.g., bench press, squat, etc.). The total work volume (repetitions × sets × load) was equated between groups. Training was performed three times a week for 8 weeks. Before and after the training period, participants were tested for VO2max, body composition, 1 RM on the bench press, knee extension and squat. Analysis of covariance (ANCOVA) was used to compare post training values between groups, using baseline values as covariates. According to the results, both groups decreased body fat and increased fat free mass with no difference between them. Whilst both groups significantly increased cardiorespiratory fitness and maximal strength, the improvements in MJ group were higher than for SJ in VO2max (5.1 and 12.5% for SJ and MJ), bench press 1 RM (8.1 and 10.9% for SJ and MJ), knee extension 1 RM (12.4 and 18.9% for SJ and MJ) and squat 1 RM (8.3 and 13.8% for SJ and MJ). In conclusion, when total work volume was equated, RT programs involving MJ exercises appear to be more efficient for improving muscle strength and maximal oxygen consumption than programs involving SJ exercises, but no differences were found for body composition.
The purpose of this study was to compare strength gains in the lower limbs, assessed by one maximum repetition (1RM) and isokinetic peak torque (PT), in young men undergoing a resistance training (RT) program. Twenty-seven young men performed resistance training twice a week for 11 weeks. Training involved two exercises for the lower body, two for the upper body and one for the midsection performed with three sets of 8-12 repetitions to momentary muscle failure. Before and after the training period, participants performed the 1RM test in the 45° leg press and knee extension PT in isokinetic dynamometry. The Pearson correlation coefficient was used to assess the relationship between the changes in 1RM and PT, and the Bland-Altman test was performed to check for agreement between the strength changes of both tests. There were significant changes in 1RM and PT of 23.98% and 15.96%, respectively (p < 0.05). The changes in leg press 1RM were significantly higher than the ones in PT. The Bland-Altman analysis revealed that the tests were not equivalent. In conclusion, professionals and researchers involved in strength assessment should be aware that the results obtained by PT and 1RM are not equivalent when evaluating individual responsiveness and/or the efficacy of an intervention on muscle strength, as the results obtained show large variations and can be even conflicting.
Resistance exercises can be considered to be multi-joint (MJ) or single-joint (SJ) in nature. Many strength coaches, trainers, and trainees believe that adding SJ exercises to a resistance training (RT) program may be required to optimize muscular size and strength. However, given that lack of time is a frequently cited barrier to exercise adoption, the time commitment resulting from these recommendations may not be convenient for many people. Therefore, it is important to find strategies that reduce the time commitment without negatively affecting results. The aim of this review was to analyze and discuss the present body of literature considering the acute responses to and long-term adaptations resulting from SJ and MJ exercise selection. Studies were deemed eligible for inclusion if they were experimental studies comparing the effects of MJ, SJ, or MJ ? SJ on dependent variables; studies were excluded if they were reviews or abstracts only, if they involved clinical populations or persons with articular or musculoskeletal problems, or if the RT intervention was confounded by other factors. Taking these factors into account, a total of 23 studies were included. For the upper and lower limbs, analysis of surface electromyographic (sEMG) activation suggests that there are no differences between SJ and MJ exercises when comparing the prime movers. However, evidence is contrasting when considering the trunk extensor musculature. Only one study directly compared the effects of MJ and SJ on muscle recovery and the results suggest that SJ exercises resulted in increased muscle fatigue and soreness. Long-term studies comparing increases in muscle size and strength in the upper limbs reported no difference between SJ and MJ exercises and no additional effects when SJ exercises were included in an MJ exercise program. For the lumbar extensors, the studies reviewed tend to support the view that this muscle group may benefit from SJ exercise. People performing RT may not need to include SJ exercises in their program to obtain equivalent results in terms of muscle activation and long-term adaptations such as hypertrophy and strength. SJ exercises may only be necessary to strengthen lumbar extensors and to correct muscular imbalances.
The purpose of this paper was to systematically review the current literature and elucidate the effects of total weekly resistance training (RT) volume on changes in measures of muscle mass via meta-regression. The final analysis comprised 34 treatment groups from 15 studies. Outcomes for weekly sets as a continuous variable showed a significant effect of volume on changes in muscle size (P = 0.002). Each additional set was associated with an increase in effect size (ES) of 0.023 corresponding to an increase in the percentage gain by 0.37%. Outcomes for weekly sets categorised as lower or higher within each study showed a significant effect of volume on changes in muscle size (P = 0.03); the ES difference between higher and lower volumes was 0.241, which equated to a percentage gain difference of 3.9%. Outcomes for weekly sets as a three-level categorical variable (<5, 5-9 and 10+ per muscle) showed a trend for an effect of weekly sets (P = 0.074). The findings indicate a graded dose-response relationship whereby increases in RT volume produce greater gains in muscle hypertrophy.
The aim of this study was compare changes in upper body muscle strength and size in trained men performing resistance training (RT) programs involving multi-joint plus single-joint (MJ+SJ) or only multi-joint (MJ) exercises. Twenty young men with at least 2 years of experience in RT were randomized in 2 groups: MJ+SJ (n = 10; age, 27.7 ± 6.6 years) and MJ (n = 10; age, 29.4 ± 4.6 years). Both groups trained for 8 weeks following a linear periodization model. Measures of elbow flexors and extensors 1-repetition maximum (1RM), flexed arm circumference (FAC), and arm muscle circumference (AMC) were taken pre- and post-training period. Both groups significantly increased 1RM for elbow flexion (4.99% and 6.42% for MJ and MJ+SJ, respectively), extension (10.60% vs 9.79%, for MJ and MJ+SJ, respectively), FAC (1.72% vs 1.45%, for MJ and MJ+SJ, respectively), and AMC (1.33% vs 3.17% for MJ and MJ+SJ, respectively). Comparison between groups revealed no significant difference in any variable. In conclusion, 8 weeks of RT involving MJ or MJ+SJ resulted in similar alterations in muscle strength and size in trained participants. Therefore, the addition of SJ exercises to a RT program involving MJ exercises does not seem to promote additional benefits to trained men, suggesting MJ-only RT to be a time-efficient approach.
The purpose of this study was to compare the effect of low- versus high-load resistance training (RT) on muscular adaptations in well-trained subjects. Eighteen young men experienced in RT were matched according to baseline strength, and then randomly assigned to 1 of 2 experimental groups: a low-load RT routine (LL) where 25-35 repetitions were performed per set per exercise (n = 9), or a high-load RT routine (HL) where 8-12 repetitions were performed per set per exercise (n = 9). During each session, subjects in both groups performed 3 sets of 7 different exercises representing all major muscles. Training was carried out 3 times per week on non-consecutive days, for 8 total weeks. Both HL and LL conditions produced significant increases in thickness of the elbow flexors (5.3 vs. 8.6%, respectively), elbow extensors (6.0 vs. 5.2%, respectively), and quadriceps femoris (9.3 vs. 9.5%, respectively), with no significant differences noted between groups. Improvements in back squat strength were significantly greater for HL compared to LL (19.6 vs. 8.8%, respectively) and there was a trend for greater increases in 1RM bench press (6.5 vs. 2.0%, respectively). Upper body muscle endurance (assessed by the bench press at 50% 1RM to failure) improved to a greater extent in LL compared to HL (16.6% vs. -1.2%, respectively). These findings indicate that both HL and LL training to failure can elicit significant increases in muscle hypertrophy among well-trained young men; however, HL training is superior for maximizing strength adaptations.
Background: Some authors suggest that single joint (SJ) exercises promote greater muscle hypertrophy because they are easier to be learned and therefore have less reliance on neural factors. On the other hand, some authors recommend an emphasis on multi-joint (MJ) exercises for maximizing muscle strength, assuming that MJ exercises are more effective than SJ execises because they enable a greater magnitude of weight to be lifted. Objectives: The present study aimed to compare the effects of MJ vs. SJ exercises on muscle size and strength gains in untrained young men. Patients and Methods: Twenty-nine young men, without prior resistance training experience, were randomly divided into two groups. One group performed (n = 14) only MJ exercises involving the elbow flexors (lat. pull downs), while the other (n = 15) trained the elbow
flexors muscles using only SJ exercises (biceps curls). Both groups trained twice a week for a period of ten weeks. The volunteers were evaluated for peak torque of elbow flexors (PT) in an isokinetic dynamometer and for muscle thickness (MT) by ultrasonography. Results: There were significant increases in MT of 6.10% and 5.83% for MJ and SJ, respectively; and there were also significant increases in PT for MJ (10.40%) and SJ (11.87%). However, the results showed no difference between groups pre or post training for MT or PT. Conclusions: In conclusion, the results of the present study suggest that MJ and SJ exercises are equally effective for promoting increases in upper body muscle strength and size in untrained men. Therefore, the selection between SJ and MJ exercises should be based on individual and practical aspects, such as, equipment availability, movement specificity, individual preferences and time commitment.
Traditional exercise order dictates large muscle group or multi-joint exercises should be performed before small muscle group or single joint exercises. The purpose of this study was to exam-ine the influence of exercise order on strength and muscle thick-ness (MT) in untrained men after 12 weeks of linear periodized resistance training. The participants were randomly assigned into three groups. One group began with large and progressed toward small muscle group exercises (LG-SM) while another started with small and advanced to large muscle group exercises (SM-LG). The exercise order for LG-SM was bench press (BP), lat pull-down (LPD), triceps extension (TE), and biceps curl (BC). The order for the SM-LG was BC, TE, LPD, and BP. The third group served as a control group (CG). Training frequency was two sessions/week with at least 72 hours between sessions. One repetition maximum (1RM) for all exercises, biceps and triceps MT (assessed by ultrasound techniques) were collected at baseline and after 12 weeks. After 12 weeks, all exercises for both training groups presented significant 1RM strength gains when compared to CG with exception of BC in LG-SM. Be-tween baseline and post training, all exercises for both training groups presented significant strength gains with exception of BC in LG-SM and BP in SM-LG. Triceps MT for both training groups were significantly higher when compared to the CG, but with no significant differences between them (p > 0.05). Signifi-cant differences in MT from pre- to post-training were found only for the SM-LG group (p < 0.05), while the biceps MT presented significant differences only between LG-SM and CG (p < 0.05), Effect size data demonstrated differences in 1RM and triceps MT based on exercise order. In conclusion, if an exercise is important for specific training goals, it should be performed at the beginning of the training session, whether or not it is a large or a small muscle group exercise.
The purpose of this study was to investigate the influence of exercise order on one-repetition maximum (1-RM) and ten-repetition maximum (10-RM) strength gains after 6 weeks of resistance training (RT) in trained men. Sixteen men were randomly assigned into two groups based on the order of exercises performed during training sessions: a group that performed large muscle group exercises first and progressed to small muscle group exercises (LG-SM); while a second group performed the opposite sequence and started with small muscle group exercises and progressed to large muscle group exercises (SM-LG). Four sessions of RT were conducted per week; all exercises were performed for three sets of 8-12 repetitions with 1-min rest intervals between sets. Maximal and submaximal strength were assessed at baseline and after 6 weeks of RT with 1-RM and 10-RM testing for the bench press (BP), lat pulldown (LPD), triceps pulley extension (TE) and biceps curl (BC), respectively. Two-way ANOVA for the 1-RM and 10-RM tests indicated a significant group x time interaction. The 1-RM values significantly increased for all exercises in both groups (P<0.05), but were not significantly different between groups. However, effect size (ES) data indicated that the LG-SM group exhibited a greater magnitude of gains (1-RM and 10-RM) for the BP and LPD exercises. Conversely, ES indicated that the SM-LG group exhibited a greater magnitude of gains (1-RM and 10-RM) for the TE and BC exercises. In conclusion, the results suggest that upper body movements should be prioritized and performed according to individual needs to maximize maximal and submaximal strength.
The aim of this study was to examine the effect of adding single-joint (SJ) exercises to a multi-joint (MJ) exercise resistance-training program on upper body muscle size and strength. Twenty-nine untrained young men participated in a 10-week training session. They were randomly divided in 2 groups: the MJ group performed only MJ exercises (lat pulldown and bench press); the MJ+SJ group performed the same MJ exercises plus SJ exercises (lat pulldown, bench press, elbow flexion, and elbow extension). Before and after the training period, the muscle thickness (MT) of the elbow flexors was measured with ultrasound, and peak torque (PT) was measured with an isokinetic dynamometer. There was a significant (p < 0.05) increase in MT (6.5% for MJ and 7.04% for MJ+SJ) and PT (10.40% for MJ and 12.85% for MJ+SJ) in both groups, but there were no between-group differences. Therefore, this study showed that the inclusion of SJ exercises in a MJ exercise training program resulted in no additional benefits in terms of muscle size or strength gains in untrained young men.
The content of this manuscript is intended to assist the reader in collecting valid and reliable data for quantifying muscular strength and power. Various drawbacks and pitfalls of specific tests, as well as recommendations for the practitioner are also provided. The content is divided into sections covering isometric, isotonic, field tests, and isokinetic modes of exercise. Inherent in these modes are both concentric and eccentric muscle actions as well as both open and closed kinetic chain activities. For Isometric testing, contractions should occur over a four to five seconds duration with a one second transition period at the start of the contraction. At least one minute of rest should be provided between contractions. For each muscle tested at each position, at least three contractions should be performed although more may be performed if deemed necessary by the tester. For isotonic testing, the 1-RM test should be performed. After the general warm-up, the subject should perform a specific warm-up set of 8 repetitions at approximately 50% of the estimated 1-RM followed by another set of 3 repetitions at 70% of the estimated 1-RM. Subsequent lifts are single repetitions of progressively heavier weights until failure. Repeat until the 1-RM is determined to the desired level of precision. The rest interval between sets should be not less than one and not more than five minutes. The optimal number of single repetitions ranges from three to five. Data and guidelines of the following field tests are also provided; vertical jump, bench press, Wingate anaerobic cycle test (WAT), and the Margaria stair-run test. For isokinetic testing, details are provided for testing peak torque, work, power, endurance, and estimation of fiber type percentages.
The purpose of this study was to determine whether the training responses observed with low-load resistance exercise to volitional fatigue translates into significant muscle hypertrophy, and compare that response to high-load resistance training. Nine previously untrained men (aged 25 [SD 3] years at the beginning of the study, standing height 1.73 [SD 0.07] m, body mass 68.9 [SD 8.1] kg) completed 6-week of high load-resistance training (HL-RT) (75% of one repetition maximal [1RM], 3-sets, 3x/wk) followed by 12 months of detraining. Following this, subjects completed 6 weeks of low load-resistance training (LL-RT) to volitional fatigue (30% 1 RM, 4 sets, 3x/wk). Increases (p < 0.05) in magnetic resonance imaging-measured triceps brachii and pectorals major muscle cross-sectional areas were similar for both HL-RT (11.9% and 17.6%, respectively) and LL-RT (9.8% and 21.1%, respectively). In addition, both groups increased (p < 0.05) 1RM and maximal elbow extension strength following training; however, the percent increases in 1RM (8.6% vs. 21.0%) and elbow extension strength (6.5% vs. 13.9%) were significantly (p < 0.05) lower with LL-RT. Both protocols elicited similar increases in muscle cross-sectional area, however differences were observed in strength. An explanation of the smaller relative increases in strength may be due to the fact that detraining after HL-RT did not cause strength values to return to baseline levels thereby producing smaller changes in strength. In addition, the results may also suggest that the consistent practice of lifting a heavy load is necessary to maximize gains in muscular strength of the trained movement. These results demonstrate that significant muscle hypertrophy can occur without high-load resistance training and suggests that the focus on percentage of external load as the important deciding factor on muscle hypertrophy is too simplistic and inappropriate.
To compare the effects of a periodic resistance training (PTR) program with those of a continuous resistance training (CTR) program on muscle size and function, 14 young men were randomly divided into a CTR group and a PTR group. Both groups performed high-intensity bench press exercise training [75 % of one repetition maximum (1-RM); 3 sets of 10 reps] for 3 days per week. The CTR group trained continuously over a 24-week period, whereas the PTR group performed three cycles of 6-week training (or retraining), with 3-week detraining periods between training cycles. After an initial 6 weeks of training, increases in cross-sectional area (CSA) of the triceps brachii and pectoralis major muscles and maximum isometric voluntary contraction of the elbow extensors and 1-RM were similar between the two groups. In the CTR group, muscle CSA and strength gradually increased during the initial 6 weeks of training. However, the rate of increase in muscle CSA and 1-RM decreased gradually after that. In the PTR group, increase in muscle CSA and strength during the first 3-week detraining/6-week retraining cycle were similar to that in the CTR group during the corresponding period. However, increase in muscle CSA and strength during the second 3-week detraining/6-week retraining cycle were significantly higher in the PTR group than in the CTR group. Thus, overall improvements in muscle CSA and strength were similar between the groups. The results indicate that 3-week detraining/6-week retraining cycles result in muscle hypertrophy similar to that occurring with continuous resistance training after 24 weeks.
Strength training generates alterations in muscle geometry, which can be monitored by imaging techniques as, for example, the ultrasound (US) technique. There is no consensus about the homogeneity of hypertrophy in different muscle sites. Therefore, the purpose of this study was to compare the muscle thickness (MT) and pennation angle (PA) in 3 different sites (50, 60, and 70% of arm length) of the biceps brachii and triceps brachii after 12 weeks of strength training. Forty-nine healthy untrained men were divided into 2 groups: Training Group ([TG, n = 40] 29.90 ± 1.72 years; 79.53 ± 11.84 kg; 173 ± 0.6 cm) and Control Group (n = 9 25.89 ± 3.59 years; 73.96 ± 9.86 kg; 171 ± 6 cm). The TG underwent a strength training program during 12 weeks, which included exercises such as a free-weight bench press, machine lat pull-down, triceps extension in lat pull-down, and standing free-weight biceps curl with a straight bar. A US apparatus was used to measure the PA and MT at the 3 sites. The maximal voluntary isometric contraction (MVC) test was conducted for each muscle group. After 12 weeks of training, a significant difference was observed between MT in biceps brachii, with an improvement of 12% in the proximal site, whereas the distal site increased by only 4.7% (p < 0.05). For the long head of the triceps brachii, the MT and PA at the 3 sites presented significant increases, but no significant variation was observed among them, probably because of the pennated-fiber arrangement. The MVC increased significantly for both muscle groups. The results indicated that the strength training program was efficient in promoting hypertrophy in both muscles, but with dissimilar responses of the pennated and fusiform muscle architecture at different arm sites.
Anthropometric measurements are a non invasive, inexpensive, and suitable method for evaluating the nutritional status in population studies with relatively large sample sizes. However, anthropometric techniques are prone to errors that could arise, for example, from the inadequate training of personnel. Despite these concerns, anthropometrical measurement error is seldom assessed in cohort studies. We describe the reliability and challenges associated with measurement of longitudinal anthropometric data in a cohort of West African HIV+ adults .
In a cohort of patients initiating antiretroviral treatment in Mali, we evaluated nutritional status using anthropometric measurements(weight, height, mid-upper arm circumference, waist circumference and triceps skinfold). Observers with no prior experience in the field of anthropometry were trained to perform anthropometrical measurements. To assess the intra- and inter-observer variability of the measurements taken in the course of the study, two sub-studies were carried out: one at the beginning and one at the end of the prospective study. Twelve patients were measured twice on two consecutive days by the same observer on both study occasions. The technical error of measurement (TEM) (absolute and relative value), and the coefficient of reliability (R) were calculated and compared across reliability studies.
According to the R and relative TEM, inter-observer reliabilities were only acceptable for height and weight. In terms of intra-observer precision, while the first and second anthropometrists demonstrated better reliability than the third, only height and weight measurements were reliable. Looking at total TEM, we observed that while measurements remained stable between studies for height and weight, circumferences and skinfolds lost precision from one occasion to the next.
Height and weight were the most reliable measurements under the study's conditions. Circumferences and skinfolds demonstrated less reliability and lost precision over time, probably as a result of insufficient supervision over the entire length of the study. Our results underline the importance of a careful observer's selection, good initial preparation, as well as the necessity of ongoing training and supervision over the entire course of a longitudinal nutritional study. Failure to do so could have major repercussions on data reliability and jeopardize its utilization.
The purpose of this study was to examine the influence of exercise order on strength and muscle volume (MV) after 12 weeks of nonlinear periodized resistance training. The participants were randomly assigned into 3 groups. One group began performing large muscle group exercises and progressed to small muscle group exercises (LG-SM), whereas another group started with small muscle group exercises and advanced to large muscle group exercises (SM-LG). The exercise order for LG-SM was bench press (BP), machine lat pull-down (LPD), triceps extension (TE), and biceps curl (BC). The order for the SM-LG was BC, TE, LPD, and BP. The third group did not exercise and served as a control group (CG). Training frequency was 2 sessions per week with at least 72 hours of rest between sessions. Muscle volume was assessed at baseline and after 6 weeks and 12 weeks of training by ultrasound techniques. One repetition maximum strength for all exercises was assessed at baseline and after 12 weeks of training. Effect size data demonstrated that differences in strength and MV were exhibited based on exercise order. Both training groups demonstrated greater strength improvements than the CG, but only BP strength increased to a greater magnitude in the LG-SM group as compared with the SM-LG. In all other strength measures (LPD, TE, and BC), the SM-LG group showed significantly greater strength increases. Triceps MV increased in the SM-LG group; however, biceps MV did not differ significantly between the training groups. In conclusion, if an exercise is important for the training goals of a program, then it should be placed at the beginning of the training session, regardless of whether or not it is a large muscle group exercise or a small muscle group exercise.
The quest to increase lean body mass is widely pursued by those who lift weights. Research is lacking, however, as to the best approach for maximizing exercise-induced muscle growth. Bodybuilders generally train with moderate loads and fairly short rest intervals that induce high amounts of metabolic stress. Powerlifters, on the other hand, routinely train with high-intensity loads and lengthy rest periods between sets. Although both groups are known to display impressive muscularity, it is not clear which method is superior for hypertrophic gains. It has been shown that many factors mediate the hypertrophic process and that mechanical tension, muscle damage, and metabolic stress all can play a role in exercise-induced muscle growth. Therefore, the purpose of this paper is twofold: (a) to extensively review the literature as to the mechanisms of muscle hypertrophy and their application to exercise training and (b) to draw conclusions from the research as to the optimal protocol for maximizing muscle growth.
It is generally recommended that exercises involving large muscle groups be placed at the beginning of a training session. However, methodological training studies manipulating exercise order and the investigation of its influence on strength have not been conducted. Therefore, the purpose of this study was to examine the influence of exercise order on strength in untrained young men after 8 weeks of training. Prior to the training program, participants were randomly assigned to three groups. One group began with large and progressed toward small muscle group exercises (G1) while another performed the opposite order (G2). The third group did not exercise and served as a control (CG). Training frequency was three sessions per week with at least 48h of rest between sessions for a total of 24 sessions in the 8-week period. One repetition maximum (1RM) was assessed for all exercises at baseline and after 8 weeks of training. Both G1 and G2 resulted in significant increases of 16.3-77.8% in 1RM compared to baseline (p<0.05). However, only the small muscle group exercises revealed significant differences between groups (p<0.05). The results demonstrated exercise order of small muscle group exercises might be particularly important during the initial stages of strength training in untrained young men.
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 measurement of human muscle size is essential when assessing the effects of training, disuse and ageing. The considered 'gold standard' for cross-sectional area measurements of muscle size is magnetic resonance imaging (MRI). However, MRI is costly and often inaccessible. The aim of the present study was to test the reproducibility and validity of a more accessible alternative method using ultrasonography (ULT). We examined the cross-sectional areas in the vastus lateralis muscle of six individuals. Axial-plane ULT scans were taken at given levels along the entire muscle length. The ULT scanning was repeated on different days (reliability) and validated against MRI-based measurements. Mean intraclass correlation coefficients were 0.998 for the reliability of ULT and 0.999 for the validity of ULT against MRI. The coefficient of variation values for cross-sectional area measurements assessed by six different experimenters were 2.1% and 0.8% for images obtained with ULT and MRI, respectively. The ULT method is a valid and reliable alternative tool for assessing cross-sectional areas of large individual human muscles. The present findings justify the application of the ULT method for the detection of changes throughout large muscles in response to training, disuse or as a consequence of sarcopenia.
It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are associated with lower SEMG and strength compared with unilateral contractions of the same muscle group. SEMG magnitude is lower for eccentric contractions than for concentric contractions. However, resistive training can reverse these trends. The last line of evidence presented involves the notion that unilateral resistive exercise of a specific limb will also result in training effects in the unexercised contralateral limb (cross-transfer or cross-education). Peripheral involvement in training-related strength increases is much more uncertain. Changes in the sensory receptors (i.e. Golgi tendon organs) may lead to disinhibition and an increased expression of muscular force. Agonist muscle activity results in limb movement in the desired direction, while antagonist activity opposes that motion. Both decreases and increases in co-activation of the antagonist have been demonstrated. A reduction in antagonist co-activation would allow increased expression of agonist muscle force, while an increase in antagonist co-activation is important for maintaining the integrity of the joint. Thus far, it is not clear what the CNS will optimise: force production or joint integrity. The following recommendations are made by the authors based on the existing literature. Motor learning theory and imagined contractions should be incorporated into strength-training practice. Static contractions at greater muscle lengths will transfer across more joint angles. Submaximal eccentric contractions should be used when there are issues of muscle pain, detraining or limb immobilisation. The reversal of antagonists (antagonist-to-agonist) proprioceptive neuromuscular facilitation contraction pattern would be useful to increase the rate of tension development in older adults, thus serving as an important prophylactic in preventing falls. When evaluating the neural changes induced by strength training using EMG recording, antagonist EMG activity should always be measured and evaluated.
Purpose:
To determine if muscle growth is important for increasing muscle strength or if changes in strength can be entirely explained from practicing the strength test.
Methods:
Thirty-eight untrained individuals performed knee extension and chest press exercise for 8 weeks. Individuals were randomly assigned to either a high-volume training group (HYPER) or a group just performing the one repetition maximum (1RM) strength test (TEST). The HYPER group performed 4 sets to volitional failure (~8-12RM) while the TEST group performed up to 5 attempts to lift as much weight as possible one time each visit.
Results:
Data are presented as mean (90% CI). The change in muscle size was greater in the HYPER group for both the upper and lower body at most but not all sites. The change in 1RM strength for both the upper [difference of -1.1 (-4.8, 2.4) kg] and lower body [difference of 1.0 (-0.7, 2.8) kg for dominant leg] was not different between groups (similar for non-dominant). Changes in isometric and isokinetic torque were not different between groups. The HYPER group observed a greater change in muscular endurance [difference of 2 (1, 4) repetitions] only in the dominant leg. There were no differences in the change between groups in upper body endurance. There were between group differences for exercise volume [mean (95% CI)] of the dominant [difference of 11049.3 (9254.6, 12844.0) kg] leg (similar for non-dominant) and chest press with the HYPER group completing significantly more total volume [difference of 13259.9 (9632.0, 16887.8) kg].
Conclusion:
These findings suggests that exercise volume nor the change in muscle size from training contributed to greater strength gains compared to just practicing the test.
SUMMARY In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 dIwkj1 for novice training, 3-4 dIwkj1 for intermediate training, and 4-5 dIwkj1 for advanced training. Similar program designs are recom- mended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (915) using short rest periods (G90 s). In the interpretation of this position stand as with prior ones, recommendations should be applied in context and should be contingent upon an individual's target goals, physical capacity, and training
Purpose:
Muscle hypertrophy in response to resistance training has been reported to occur nonuniformly along the length of the muscle. The purpose of the present study was to examine whether the regional difference in muscle hypertrophy induced by a training intervention corresponds to the regional difference in muscle activation in the training session.
Methods:
Twelve young men participated in a training intervention program for the elbow extensors with a multijoint resistance exercise for 12 wk (3 d · wk(-1)). Before and after the intervention, cross-sectional areas of the triceps brachii along its length were measured with magnetic resonance images. A series of transverse relaxation time (T2)-weighted magnetic resonance images was recorded before and immediately after the first session of training intervention. The T2 was calculated for each pixel within the triceps brachii. In the images recorded after the session, the number of pixels with a T2 greater than the threshold (mean + 1 SD of T2 before the session) was expressed as the ratio to the whole number of pixels within the muscle and used as an index of muscle activation (percent activated area).
Results:
The percent activated area of the triceps brachii in the first session was significantly higher in the middle regions than that in the most proximal region. Similarly, the relative change in cross-sectional area induced by the training intervention was also significantly greater in the middle regions than the most proximal region.
Conclusion:
The results suggest that nonuniform muscle hypertrophy after training intervention is due to the region-specific muscle activation during the training session.
We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 ± 1 yr, 22.6 ± 2.1 kg/m(2); means ± SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 ± 1.8%, 80%-1 = 3.2 ± 0.8%, and 80%-3= 7.2 ± 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.
The purpose of this study was to examine if the regional difference in muscle hypertrophy after chronic resistance training is associated with muscle activation after one session of resistance exercise. Twelve men performed one session of resistance exercise of elbow extensors. Before and immediately after the exercise, transverse relaxation time (T2)-weighted magnetic resonance (MR) images of upper arm were recorded to evaluate the muscle activation along its length. In the MR images, T2 for the pixels within the triceps brachii muscle was quantified. The number of pixels with T2 greater than the threshold (mean + 1SD of T2 before the exercise) was expressed as the ratio to the number of pixels occupied by the muscle (%activated area). Another 12 subjects completed 12 weeks of training intervention (3 days per week), which consisted of the same program variables as used in the experiment for the T2 measurement. The cross-sectional areas of the triceps brachii before and after the training intervention were measured from MR images of upper arm. The %activated area of the triceps brachii induced by one session of the exercise was found to be significantly lower in the distal region than the middle and proximal regions. Similarly, the relative increase in muscle cross-sectional area after the 12 weeks of training intervention was significantly less in the distal region than the middle and proximal regions. The results suggest that the regional difference in muscle hypertrophy after chronic resistance training is attributable to the regional difference in muscle activation during the exercise.
Quadriceps muscle and fibre cross-sectional areas (CSA), torque and neural activation were studied in seven healthy males during 6 months of weight training on alternate days with six series of eight unilateral leg extensions at 80% of one repetition maximum. After training, the quadriceps cross-sectional area increased by 18.8 +/- 7.2% (P < 0.001) and 19.3 +/- 6.7% (P < 0.001) in the distal and proximal regions respectively, and by 13.0 +/- 7.2% (P < 0.001) in the central region of the muscle. Hypertrophy was significantly different between and within the four constituents of the quadriceps. Biopsies of the vastus lateralis at mid-thigh did not show any increase in mean fibre cross-sectional area. Maximum isometric voluntary torque increased by 29.6 +/- 7.9%-21.1 +/- 8.6% (P < 0.01-0.05) between 100 degrees and 160 degrees of knee extension, but no change in the optimum angle (110 degrees-120 degrees) for torque generation was found. A 12.0 +/- 10.8% (P < 0.02) increase in torque per unit area together with a right shift in the IEMG-torque relation and no change in maximum IEMG were observed. Time to peak isometric torque decreased by 45.8% (P < 0.03) but no change in time to maximum IEMG was observed. In conclusion, strength training of the quadriceps results in a variable hypertrophy of its components without affecting its angle-torque relation. The increase in torque per unit area, in the absence of changes in IEMG, may indicate changes in muscle architecture. An increase in muscle-tendon stiffness may account for the decrease in time to peak torque.
The loss of hydrostatic pressure that occurs as a person moves from the standing to the supine position causes a fluid redistribution that may confound the measurement of thigh cross-sectional area (CSA) if data are obtained while tissue fluid content is in flux. To determine the effects of changing postural position on thigh tissue CSA, mid-thigh axial scans of 13 older women were obtained at 5, 10 and 15 min of supine rest using computed tomography (CT). Scans were analysed for changes in CSA of subcutaneous fat (SF), low density muscle (LDM) and normal density muscle (NDM). A significant decrease from baseline was found in the CSA of NDM at 15 min [2.3+/-0.8 cm2 (+/-SE), 1.6%, P<0.05], with no change in LDM or SF CSA among any of the time intervals. The results of the current study suggest that potential measurement error can be minimized when baseline and follow-up CT-derived images of mid-thigh CSA are obtained within the first 10 min the subject assumes the supine position and that the CSA of NDM and LDM may be affected differently by supine rest.
American College of Sports Medicine Position Stand. Progression models in resistance training for healthy adults
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