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How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency

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Abstract

Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference.

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... These studies were published between 2009 and 2020 and comprised 178 primary studies corresponding to 4,704 participants. The 14 selected meta-analyses were classified attending to the analyzed variable, differentiating between volume (Krieger, 2010;Schoenfeld et al., 2017a), frequency (Schoenfeld et al., 2019a), intensity (Schoenfeld et al., 2016a(Schoenfeld et al., , 2017cGrgic, 2020), contraction type (Roig et al., 2009;Schoenfeld et al., 2017b), repetition duration (Schoenfeld et al., 2015), exercises order (Nunes et al., 2020), time of day (Grgic et al., 2019), periodization followed and blood-flow restriction (Slysz et al., 2016;Lixandrão et al., 2018). ...
... The methodological quality of the 14 included meta-analyses is presented in Table 2. Nine meta-analyses were categorized as high quality, presenting values of 81 and 88% (i.e., 13 items satisfied) (Schoenfeld et al., 2015(Schoenfeld et al., , 2017a(Schoenfeld et al., ,b, 2019aGrgic et al., 2017Grgic et al., , 2019Lixandrão et al., 2018;Nunes et al., 2020). The remaining meta-analyses were rated as moderate quality, with values between 63 and 75% (i.e., from 10 to 12 items satisfied) (Roig et al., 2009;Krieger, 2010;Schoenfeld et al., 2016aSchoenfeld et al., , 2017cSlysz et al., 2016;Grgic, 2020). ...
... The remaining meta-analyses were rated as moderate quality, with values between 63 and 75% (i.e., from 10 to 12 items satisfied) (Roig et al., 2009;Krieger, 2010;Schoenfeld et al., 2016aSchoenfeld et al., , 2017cSlysz et al., 2016;Grgic, 2020). According to GRADE, 8 metaanalyses were based on high-quality primary studies (i.e., high GRADE) (Roig et al., 2009;Slysz et al., 2016;Grgic et al., 2017Grgic et al., , 2019Schoenfeld et al., 2017c;Lixandrão et al., 2018;Grgic, 2020;Nunes et al., 2020) while the other 7 meta-analyses did not presented information regarding to quality (Krieger, 2010;Schoenfeld et al., 2015Schoenfeld et al., , 2016aSchoenfeld et al., , 2017aSchoenfeld et al., ,b, 2019a. ...
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This umbrella review aimed to analyze the different variables of resistance training and their effect on hypertrophy, and to provide practical recommendations for the prescription of resistance training programs to maximize hypertrophy responses. A systematic research was conducted through of PubMed/MEDLINE, SPORTDiscus and Web of Science following the preferred reporting items for systematic reviews and meta-analyses statement guidelines. A total of 52 meta-analyses were found, of which 14 met the inclusion criteria. These studies were published between 2009 and 2020 and comprised 178 primary studies corresponding to 4784 participants. Following a methodological quality analysis, nine meta-analyses were categorized as high quality, presenting values of 81-88%. The remaining meta-analyses were rated as moderate quality, with values between 63-75%. Based on this umbrella review, we can state that at least 10 sets per week per muscle group is optimal, that eccentric contractions seem important, very slow repetitions (≥10s) should be avoided, and that blood flow restriction might be beneficial for some individuals. In addition, other variables as, exercise order, time of the day and type of periodization appear not to directly influence the magnitude of muscle mass gains. These findings provide valuable information for the design and configuration of the resistance training program with the aim of optimizing muscle hypertrophy.
... General guidelines recommend that people train 2-3 times per week [1]; unfortunately, this recommendation may cause those who find it challenging to train several times a week to not train at all. However, emerging evidence indicates that it is possible to achieve similar training effects by training once a week compared to a higher frequency when total weekly volume is equated [10,11]. In a meta-analysis from 2018, Ralston et al. compared strength gains from low training frequency (1 day per week), medium training frequency (2 days per week), and high training frequency (≥ 3 days per week) for each muscle group [10]. ...
... Still, in real-life situations, a higher training frequency allows for a higher training volume and therefore often results in greater strength gains as demonstrated in a meta-analysis by Grgic et al. [12]. A recently published meta-analysis by Schoenfeld et al. found no compelling evidence that training frequency confers a meaningful impact on muscle hypertrophy when training volume is matched [11]. However, as higher training volumes can be expected from higher training frequencies in real-life situations, a higher training frequency is likely preferable for those seeking to maximize muscle strength and hypertrophy regardless of the time commitment. ...
... It is noteworthy that weekly training volume appears to be a more crucial factor than training frequency. While general guidelines recommend training a given muscle group two to three times per week [1], recent reviews and metaanalyses indicate that training frequency appears to be of limited importance when weekly training volume is matched [11]. This is of practical relevance as it allows individuals to choose a weekly training frequency based on their schedule. ...
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Lack of time is among the more commonly reported barriers for abstention from exercise programs. The aim of this review was to determine how strength training can be most effectively carried out in a time-efficient manner by critically evaluating research on acute training variables, advanced training techniques, and the need for warm-up and stretching. When programming strength training for optimum time-efficiency we recommend prioritizing bilateral, multi-joint exercises that include full dynamic movements (i.e. both eccentric and concentric muscle actions), and to perform a minimum of one leg pressing exercise (e.g. squats), one upper-body pulling exercise (e.g. pull-up) and one upper-body pushing exercise (e.g. bench press). Exercises can be performed with machines and/or free weights based on training goals, availability, and personal preferences. Weekly training volume is more important than training frequency and we recommend performing a minimum of 4 weekly sets per muscle group using a 6–15 RM loading range (15–40 repetitions can be used if training is performed to volitional failure). Advanced training techniques, such as supersets, drop sets and rest-pause training roughly halves training time compared to traditional training, while maintaining training volume. However, these methods are probably better at inducing hypertrophy than muscular strength, and more research is needed on longitudinal training effects. Finally, we advise restricting the warm-up to exercise-specific warm-ups, and only prioritize stretching if the goal of training is to increase flexibility. This review shows how acute training variables can be manipulated, and how specific training techniques can be used to optimize the training response: time ratio in regard to improvements in strength and hypertrophy. Graphic Abstract
... Training volume has received particular interest in the resistance training field since it is posited to be one of the most effective variables to improve muscle hypertrophy and health-related outcomes [1][2][3][4]. The resistance-training volume is defined as the measure of the total amount of work carried out in a single training session or summed over weeks or months of training [5]. ...
... A simple way to calculate training volume is through the number of sets. In a recent review, Schoenfeld et al. [4] suggested that equating the number of sets per exercise per week is necessary to determine causality when verifying the actual influence of weekly training frequency on muscle hypertrophy. If this is not done, the differences in weekly set-volume may confound the ability to draw proper inferences [4,19]. ...
... In a recent review, Schoenfeld et al. [4] suggested that equating the number of sets per exercise per week is necessary to determine causality when verifying the actual influence of weekly training frequency on muscle hypertrophy. If this is not done, the differences in weekly set-volume may confound the ability to draw proper inferences [4,19]. Indeed, the number of sets may be used to equate training volume in most frequency studies [19], particularly when the difference in the number of sessions per week compared is ≤ 2 (e.g., 1-2 vs. 3 x/week). ...
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Article
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).
... In this context, a higher training frequency may help to achieve a greater volume of training, which may in turn enhance the hypertrophic response [5][6][7] . However, systematic reviews with meta-analysis showed no significant difference between a higher and a lower frequency on a volume-equated basis for both muscle strength 8 and hypertrophy 6 . ...
... In this context, a higher training frequency may help to achieve a greater volume of training, which may in turn enhance the hypertrophic response [5][6][7] . However, systematic reviews with meta-analysis showed no significant difference between a higher and a lower frequency on a volume-equated basis for both muscle strength 8 and hypertrophy 6 . Therefore, a higher weekly RT frequency seems to exert an influence on muscle strength and hypertrophy gains only when such protocol results in a higher total load lifted (TLL − sets × repetitions × load [kg]) compared to a low RT frequency 6,7 . ...
... However, systematic reviews with meta-analysis showed no significant difference between a higher and a lower frequency on a volume-equated basis for both muscle strength 8 and hypertrophy 6 . Therefore, a higher weekly RT frequency seems to exert an influence on muscle strength and hypertrophy gains only when such protocol results in a higher total load lifted (TLL − sets × repetitions × load [kg]) compared to a low RT frequency 6,7 . ...
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Article
Background: The present study investigated the mid-term effects of training muscle groups once- versus twice-daily on morphofunctional adaptations in trained men. Methods: Participants were randomly assigned to 1 of 2 experimental groups: 1 daily session per muscle group (1S, n = 11), where every muscle group was trained once a day or 2 daily sessions per muscle group (2S, n = 12), where every muscle group was trained twice. Testing was conducted before intervention and after 8 weeks for maximal strength (1RM) and muscular endurance (60%1RM) for bench press and parallel back squat exercises, and muscle thickness (MT) of the biceps brachii, triceps brachii, vastus lateralis, anterior quadriceps and pectoralis major. Results: The major findings were as follows: (a) the increase in 1RM back squat was significantly greater in 2S (Δ=16.1%) compared to 1S (Δ=7.8%) (p<0.05) and (b) both groups significantly increased bench press 1RM (1S: Δ=4.6%; 2S: Δ=6.8%), back squat 60% 1RM (1S: Δ= 19.0%; 2S: Δ= 24.3%), bench press 60% 1RM (1S: Δ= 15.4%; 2S: Δ= 24.0%) and all MT outcomes (p< 0.05 for all), with no differences between experimental groups (1S and 2S). Conclusions: This study provides evidence that a twice-daily resistance training augments lower-body muscular strength; however, the daily frequency does not seem to have any additive effect on upper-body muscular strength, muscular endurance, and muscle hypertrophy in trained men.
... increase in vastus lateralis CSA) (Earp et al., 2015) compared with smaller gains following two weekly sessions (14% increase in thigh muscle volume) (Fathi et al., 2019). This is in agreement with the literature about traditional resistance training (Wernbom et al., 2007;Schoenfeld et al., 2019;Schoenfeld et al., 2021). More specifically, in a systematic review with meta-analysis of the effects of traditional resistance training frequency on skeletal muscle hypertrophy in healthy individuals, Schoenfeld et al. (2019) reported a slightly larger effect of higher compared with lower frequencies of training on hypertrophic outcomes when training volume was not equated between conditions. ...
... This is in agreement with the literature about traditional resistance training (Wernbom et al., 2007;Schoenfeld et al., 2019;Schoenfeld et al., 2021). More specifically, in a systematic review with meta-analysis of the effects of traditional resistance training frequency on skeletal muscle hypertrophy in healthy individuals, Schoenfeld et al. (2019) reported a slightly larger effect of higher compared with lower frequencies of training on hypertrophic outcomes when training volume was not equated between conditions. However, under equated-volume conditions, no additional effects of higher compared with lower frequencies of training were reported . ...
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Article
Objective: To examine the effect of plyometric jump training on skeletal muscle hypertrophy in healthy individuals. Methods: A systematic literature search was conducted in the databases PubMed, SPORTDiscus, Web of Science, and Cochrane Library up to September 2021. Results: Fifteen studies met the inclusion criteria. The main overall finding (44 effect sizes across 15 clusters median = 2, range = 1–15 effects per cluster) indicated that plyometric jump training had small to moderate effects [standardised mean difference (SMD) = 0.47 (95% CIs = 0.23–0.71); p < 0.001] on skeletal muscle hypertrophy. Subgroup analyses for training experience revealed trivial to large effects in non-athletes [SMD = 0.55 (95% CIs = 0.18–0.93); p = 0.007] and trivial to moderate effects in athletes [SMD = 0.33 (95% CIs = 0.16–0.51); p = 0.001]. Regarding muscle groups, results showed moderate effects for the knee extensors [SMD = 0.72 (95% CIs = 0.66–0.78), p < 0.001] and equivocal effects for the plantar flexors [SMD = 0.65 (95% CIs = −0.25–1.55); p = 0.143]. As to the assessment methods of skeletal muscle hypertrophy, findings indicated trivial to small effects for prediction equations [SMD = 0.29 (95% CIs = 0.16–0.42); p < 0.001] and moderate-to-large effects for ultrasound imaging [SMD = 0.74 (95% CIs = 0.59–0.89); p < 0.001]. Meta-regression analysis indicated that the weekly session frequency moderates the effect of plyometric jump training on skeletal muscle hypertrophy, with a higher weekly session frequency inducing larger hypertrophic gains [β = 0.3233 (95% CIs = 0.2041–0.4425); p < 0.001]. We found no clear evidence that age, sex, total training period, single session duration, or the number of jumps per week moderate the effect of plyometric jump training on skeletal muscle hypertrophy [β = −0.0133 to 0.0433 (95% CIs = −0.0387 to 0.1215); p = 0.101–0.751]. Conclusion: Plyometric jump training can induce skeletal muscle hypertrophy, regardless of age and sex. There is evidence for relatively larger effects in non-athletes compared with athletes. Further, the weekly session frequency seems to moderate the effect of plyometric jump training on skeletal muscle hypertrophy, whereby more frequent weekly plyometric jump training sessions elicit larger hypertrophic adaptations.
... increase in vastus lateralis CSA) (Earp et al., 2015) compared with smaller gains following two weekly sessions (14% increase in thigh muscle volume) (Fathi et al., 2019). This is in agreement with the literature about traditional resistance training (Wernbom et al., 2007;Schoenfeld et al., 2019;Schoenfeld et al., 2021). More specifically, in a systematic review with meta-analysis of the effects of traditional resistance training frequency on skeletal muscle hypertrophy in healthy individuals, Schoenfeld et al. (2019) reported a slightly larger effect of higher compared with lower frequencies of training on hypertrophic outcomes when training volume was not equated between conditions. ...
... This is in agreement with the literature about traditional resistance training (Wernbom et al., 2007;Schoenfeld et al., 2019;Schoenfeld et al., 2021). More specifically, in a systematic review with meta-analysis of the effects of traditional resistance training frequency on skeletal muscle hypertrophy in healthy individuals, Schoenfeld et al. (2019) reported a slightly larger effect of higher compared with lower frequencies of training on hypertrophic outcomes when training volume was not equated between conditions. However, under equated-volume conditions, no additional effects of higher compared with lower frequencies of training were reported . ...
Full-text available
Article
Objective: To examine the effect of plyometric jump training on skeletal muscle hypertrophy in healthy individuals. Methods: A systematic literature search was conducted in the databases PubMed, SPORTDiscus, Web of Science, and Cochrane Library up to September 2021. Results: Fifteen studies met the inclusion criteria. The main overall finding (44 effect sizes across 15 clusters median = 2, range = 1–15 effects per cluster) indicated that plyometric jump training had small to moderate effects [standardised mean difference (SMD) = 0.47 (95% CIs = 0.23–0.71); p < 0.001] on skeletal muscle hypertrophy. Subgroup analyses for training experience revealed trivial to large effects in non-athletes [SMD = 0.55 (95% CIs = 0.18–0.93); p = 0.007] and trivial to moderate effects in athletes [SMD = 0.33 (95% CIs = 0.16–0.51); p = 0.001]. Regarding muscle groups, results showed moderate effects for the knee extensors [SMD = 0.72 (95% CIs = 0.66–0.78), p < 0.001] and equivocal effects for the plantar flexors [SMD = 0.65 (95% CIs = −0.25–1.55); p = 0.143]. As to the assessment methods of skeletal muscle hypertrophy, findings indicated trivial to small effects for prediction equations [SMD = 0.29 (95% CIs = 0.16–0.42); p < 0.001] and moderate-to-large effects for ultrasound imaging [SMD = 0.74 (95% CIs = 0.59–0.89); p < 0.001]. Meta-regression analysis indicated that the weekly session frequency moderates the effect of plyometric jump training on skeletal muscle hypertrophy, with a higher weekly session frequency inducing larger hypertrophic gains [β = 0.3233 (95% CIs = 0.2041–0.4425); p < 0.001]. We found no clear evidence that age, sex, total training period, single session duration, or the number of jumps per week moderate the effect of plyometric jump training on skeletal muscle hypertrophy [β = −0.0133 to 0.0433 (95% CIs = −0.0387 to 0.1215); p = 0.101–0.751]. Conclusion: Plyometric jump training can induce skeletal muscle hypertrophy, regardless of age and sex. There is evidence for relatively larger effects in non-athletes compared with athletes. Further, the weekly session frequency seems to moderate the effect of plyometric jump training on skeletal muscle hypertrophy, whereby more frequent weekly plyometric jump training sessions elicit larger hypertrophic adaptations.
... Some of these studies reported no significant differences between higher (full-body) and lower frequencies (SPLIT) [5,6], while others demonstrated a potentially better hypertrophic effect for the full-body routine [2,7]. Indeed, systematic reviews with meta-analysis showed no significant difference between higher and lower frequency on a volume-equated basis for both muscle strength [8] and hypertrophy [9] outcomes. ...
... Moreover, these results seem to be in line with several studies that observed no between-groups difference in muscle hypertrophy when comparing frequencies of 1 vs 2 [10,11,13]; 2 vs 4 [23]; 1 vs 5 [5]; 3 vs 6 sessions·wk-1 per muscle group [12,24]. Interestingly, although the findings of the current study essentially reflect the results of a previous meta-analysis [9], it also differs from a previous investigation from our research group that reported that muscle hypertrophy was potentiated when adopting a higher training frequency [7]. Some methodological differences must be acknowledged in order to compare this distinct results. ...
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Article
The purpose of this study was to investigate the chronic effects of training each muscle group through a split-body routine on 2 versus 3 days per week on muscle strength and morphological adaptations in recreationally resistance-trained men with the number of sets per muscle group equated between conditions. Twenty healthy men (28.8 ± 6.1 years [range 19 to 37 years]; 172.8 ± 5.1 cm; total body mass = 70.2 ± 7.4 kg; RT experience = 3.5 ± 0.8 years [range 2 to 5 years]; RT frequency = 4.4 ± 0.5 session·wk-1) volunteered to participate in this study. Subjects were randomly assigned into 2 experimental groups: 2 sessions·wk-1 per muscle (G2x, n = 10), in which every muscle was trained twice a week with 9 sets/session, or 3 sessions·wk-1 per muscle (G3x, n = 10), in which every muscle was trained thrice a week with 6 sets/session. All other variables were held constant over the 8-week study period (training intensity: 8-12 maximum repetitions; rest intervals: 60 seconds between sets). No significant difference between conditions was observed for maximal strength in the back squat (G2x: ∆ = 51.5%; G3x: ∆ = 56.3%, p = 0.337) and bench press (G2x: ∆ = 15.4%; G3x: ∆ = 20.5%, p = 0.756), muscle thickness of the biceps brachii (G2x: ∆ = 6.9%; G3x: ∆ = 8.9%, p = 0.495), triceps brachii (G2x: ∆ = 8.4%; G3x: ∆ = 15.7%, p = 0.186), vastus lateralis (G2x: ∆ = 11.2%; G3x: ∆ = 5.0%, p = 0.082 and anterior quadriceps (rectus femoris and vastus intermedius) (G2x: ∆ = 12.1%; G3x: ∆ = 21.0%, p = 0.102). In conclusion, both G2x and G3x can result in significant increases in muscle strength and size in recreationally trained men.
... However, these findings were based on relatively few number of studies with several important limitations e.g., low sample size, resistancetrained women not representative of the general population and equated training volume (same number of sets per week). Further, few of the studies comparing different frequencies with equated training volumes have used non-resistance trained individuals as participants [20]. Consequently it would be of interest to compare resistance training programs with different training frequencies among non-resistance trained women to strengthen research-based recommendations for training. ...
... The mean difference in total kg lifted was 81 (− 2208, 2459) kg, p = 0.947). For FB, weekly training volume ranged from 22,771 (20,855,24,687) kg to 31,348 (29,433, 33,265), with the lowest training volume noted during week 1 and the highest in week 7. For SPLIT, weekly training volume ranged from 23,543 (21,345,25,741) kg to 32,215 (30,017,34,412) kg, with the lowest training volume noted during week 1 and the highest in week 8. Figure 3 provides a complete illustration of weekly training volume throughout the intervention. ...
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Article
Background The aim of this study was to assess the efficacy of a 12-week upper/lower split- versus a full-body resistance training program on maximal strength, muscle mass and explosive characteristics. Fifty resistance untrained women were pair-matched according to baseline strength and randomized to either a full-body (FB) routine that trained all of the major muscle groups in one session twice per week, or a split-body program (SPLIT) that performed 4 weekly sessions (2 upper body and 2 lower body). Both groups performed the same exercises and weekly number of sets and repetitions. Each exercise was performed with three sets and 8–12 repetition maximum (RM) loading. Study outcomes included maximal strength, muscle mass, jump height and maximal power output. Results No between-group differences were found in any of the variables. However, both FB and SPLIT increased mean 1-RM from pre- to post-test in the bench press by 25.5% versus 30.0%, lat pulldown by 27.2% versus 26.0% and leg press by 29.2% versus 28.3%, respectively. Moreover, both FB and SPLIT increased jump height by 12.5% versus 12.5%, upper-body power by 20.3% versus 16.7% and muscle mass by 1.9% versus 1.7%, p < 0.01, respectively. Conclusions This study did not show any benefits for split-body resistance-training program compared to full-body resistance training program on measures of maximal- and explosive muscle strength, and muscle mass. Trial registration : ISRCTN81548172, registered 15. February 2022.
... To optimize the effects of resistance training, the manipulation of several factors, primarily training volume, load, and frequency, is central (American College of Sports Medicine, 2009). The current recommendations on training frequency, defined as the number of sets or training sessions on a given muscle group performed within a given timeframe, have been criticized for being based on limited evidence (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). The latest meta-analyses suggest a limited role for training frequency, given that the weekly training volume is kept identical between groups (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). ...
... The current recommendations on training frequency, defined as the number of sets or training sessions on a given muscle group performed within a given timeframe, have been criticized for being based on limited evidence (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). The latest meta-analyses suggest a limited role for training frequency, given that the weekly training volume is kept identical between groups (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). However, in the current literature, studies isolating frequency by keeping total weekly volume matched between groups are limited; most include untrained participants and compare training frequencies of one to three sessions per week. ...
Article
Background: Postural balance represents a fundamental movement skill for the successful performance of everyday and sport-related activities. There is ample evidence on the effectiveness of balance training on balance performance in athletic and non-athletic population. However, less is known on potential transfer effects of other training types, such as plyometric jump training (PJT) on measures of balance. Given that PJT is a highly dynamic exercise mode with various forms of jump-landing tasks, high levels of postural control are needed to successfully perform PJT exercises. Accordingly, PJT has the potential to not only improve measures of muscle strength and power but also balance. Objective: To systematically review and synthetize evidence from randomized and non-randomized controlled trials regarding the effects of PJT on measures of balance in apparently healthy participants. Methods: Systematic literature searches were performed in the electronic databases PubMed, Web of Science, and SCOPUS. A PICOS approach was applied to define inclusion criteria, (i) apparently healthy participants, with no restrictions on their fitness level, sex, or age, (ii) a PJT program, (iii) active controls (any sport-related activity) or specific active controls (a specific exercise type such as balance training), (iv) assessment of dynamic, static balance pre- and post-PJT, (v) randomized controlled trials and controlled trials. The methodological quality of studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. This meta-analysis was computed using the inverse variance random-effects model. The significance level was set at p < 0.05. Results: The initial search retrieved 8,251 plus 23 records identified through other sources. Forty-two articles met our inclusion criteria for qualitative and 38 for quantitative analysis (1,806 participants [990 males, 816 females], age range 9–63 years). PJT interventions lasted between 4 and 36 weeks. The median PEDro score was 6 and no study had low methodological quality (�3). The analysis revealed significant small effects of PJT on overall (dynamic and static) balance (ES = 0.46; 95% CI = 0.32–0.61; p < 0.001), dynamic (e.g., Y-balance test) balance (ES = 0.50; 95% CI = 0.30–0.71; p < 0.001), and static (e.g., flamingo balance test) balance (ES = 0.49; 95% CI = 0.31–0.67; p<0.001). The moderator analyses revealed that sex and/or age did not moderate balance performance outcomes. When PJT was compared to specific active controls (i.e., participants undergoing balance training, whole body vibration training, resistance training), both PJT and alternative training methods showed similar effects on overall (dynamic and static) balance (p = 0.534). Specifically, when PJT was compared to balance training, both training types showed similar effects on overall (dynamic and static) balance (p = 0.514). Conclusion: Compared to active controls, PJT showed small effects on overall balance, dynamic and static balance. Additionally, PJT produced similar balance improvements compared to other training types (i.e., balance training). Although PJT is widely used in athletic and recreational sport settings to improve athletes’ physical fitness (e.g., jumping; sprinting), our systematic review with meta-analysis is novel in as much as it indicates that PJT also improves balance performance. The observed PJT-related balance enhancements were irrespective of sex and participants’ age. Therefore, PJT appears to be an adequate training regime to improve balance in both, athletic and recreational settings.
... To optimize the effects of resistance training, the manipulation of several factors, primarily training volume, load, and frequency, is central (American College of Sports Medicine, 2009). The current recommendations on training frequency, defined as the number of sets or training sessions on a given muscle group performed within a given timeframe, have been criticized for being based on limited evidence (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). The latest meta-analyses suggest a limited role for training frequency, given that the weekly training volume is kept identical between groups (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). ...
... The current recommendations on training frequency, defined as the number of sets or training sessions on a given muscle group performed within a given timeframe, have been criticized for being based on limited evidence (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). The latest meta-analyses suggest a limited role for training frequency, given that the weekly training volume is kept identical between groups (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). However, in the current literature, studies isolating frequency by keeping total weekly volume matched between groups are limited; most include untrained participants and compare training frequencies of one to three sessions per week. ...
Article
Studies comparing children and adolescents from different periods have shown that physical activity and fitness decreased in the last decades, which might have important adverse health consequences such as body fat gain and poor metabolic health. The purpose of the current article is to present the benefits of high-intensity multimodal training (HIMT), such as CrossFit, to young people, with a critical discussion about its potential benefits and concerns. During HIMT, exercise professionals might have an opportunity to promote positive changes in physical function and body composition in children and adolescents, as well as to promote improvements in mental health and psychosocial aspects. Moreover, this might serve as an opportunity to educate them about the benefits of a healthy lifestyle and overcome the perceived barriers for being physically active. In technical terms, the characteristics of HIMT, such as, the simultaneous development of many physical capacities and diversity of movement skills and exercise modalities might be particularly interesting for training young people. Many concerns like an increased risk of injury and insufficient recovery might be easily addressed and not become a relevant problem for this group.
... Additional improvements in body composition and blood lipids were seen only after HIIT was performed three times per week, indicating an influence of frequency [65]. Resistance training, the other component of HIFT, demonstrated superior hypertrophic outcomes after two times per week versus volume-matched exercise one time per week, also indicating an influence of frequency [66,67]. ...
... This dose is in line with the global physical activity guidelines [22]. However, HIIT and resistance exercise, two components of HIFT, have shown health and fitness benefits as little as 2 times per week [64][65][66][67]. No studies have investigated the health benefits of HIFT less than 3 times per week. ...
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Background Individuals with metabolic syndrome (MetS) are at a greater risk for developing atherosclerotic cardiovascular disease (ASCVD) than those without MetS, due to underlying endothelial dysfunction, dyslipidemia, and insulin resistance. Exercise is an effective primary and secondary prevention strategy for MetS; however, less than 25% of adults meet the minimum stated public recommendations. Barriers often identified are lack of enjoyment and lack of time. High-intensity functional training (HIFT), a time-efficient modality of exercise, has shown some potential to elicit positive affectivity and elicit increased fitness and improved glucose metabolism. However, the effects of HIFT on dyslipidemia and endothelial dysfunction have not been explored nor have the effects been explored in a population with MetS. Additionally, no studies have investigated the minimal dose of HIFT per week to see clinically meaningful changes in cardiometabolic health. The purpose of this study is to (1) determine the dose-response effect of HIFT on blood lipids, insulin resistance, and endothelial function and (2) determine the dose-response effect of HIFT on body composition, fitness, and perceived enjoyment and intention to continue the exercise. Methods/design In this randomized, dose-response trial, participants will undergo a 12-week HIFT intervention of either 1 day/week, 2 days/week, or 3 days/week of supervised, progressive exercise. Outcomes assessed at baseline and post-intervention will be multiple cardiometabolic markers, and fitness. Additionally, the participant’s affective response will be measured after the intervention. Discussion The findings of this research will provide evidence on the minimal dose of HIFT per week to see clinically meaningful improvements in the risk factors of MetS, as well as whether this modality is likely to mitigate the barriers to exercise. If an effective dose of HIFT per week is determined and if this modality is perceived positively, it may provide exercise specialists and health care providers a tool to prevent and treat MetS. Trial registration ClinicalTrials.gov NCT05001126 . August 11, 2021.
... To optimize the effects of resistance training, the manipulation of several factors, primarily training volume, load, and frequency, is central (American College of Sports Medicine, 2009). The current recommendations on training frequency, defined as the number of sets or training sessions on a given muscle group performed within a given timeframe, have been criticized for being based on limited evidence (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). The latest meta-analyses suggest a limited role for training frequency, given that the weekly training volume is kept identical between groups (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). ...
... The current recommendations on training frequency, defined as the number of sets or training sessions on a given muscle group performed within a given timeframe, have been criticized for being based on limited evidence (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). The latest meta-analyses suggest a limited role for training frequency, given that the weekly training volume is kept identical between groups (Grgic et al., 2018;Ralston et al., 2018;Schoenfeld et al., 2019). However, in the current literature, studies isolating frequency by keeping total weekly volume matched between groups are limited; most include untrained participants and compare training frequencies of one to three sessions per week. ...
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The main goal of the current study was to compare the effects of volume-equated training frequency on gains in muscle mass and strength. In addition, we aimed to investigate whether the effect of training frequency was affected by the complexity, concerning the degrees of freedom, of an exercise. Participants were randomized to a moderate training frequency group (two weekly sessions) or high training frequency group (four weekly sessions). Twenty-one participants (male: 11, female: 10, age: 25.9 ± 4.0) completed the 9-week whole-body progressive heavy resistance training intervention with moderate ( n = 13) or high ( n = 8) training frequency. Whole-body and regional changes in lean mass were measured using dual-energy x-ray absorptiometry, while the vastus lateralis thickness was measured by ultrasound. Changes in muscle strength were measured as one repetition maximum for squat, hack squat, bench press, and chest press. No differences between groups were observed for any of the measures of muscle growth or muscle strength. Muscle strength increased to a greater extent in hack squat and chest press than squat and bench press for both moderate (50 and 21% vs. 19 and 14%, respectively) and high-frequency groups (63 and 31% vs. 19 and 16%, respectively), with no differences between groups. These results suggest that training frequency is less decisive when weekly training volume is equated. Further, familiarity with an exercise seems to be of greater importance for strength adaptations than the complexity of the exercise.
... The management of resistance training variables for adaptations is well established within academic literature. Empirical studies and subsequent systematic reviews and/or meta-analyses have considered manipulation of load [1], repetition duration [2], weekly volume [3], frequency [4], exercise order [5], and range of motion [6], among other variables, in an attempt to optimise exercise induced adaptations. However, in none of these reviews was training supervision (SUP) discussed as a potentially confounding variable. ...
... Please consider donating at www.storkinesiology.org/annual 4 Interestingly, many studies considering adolescent or children performing resistance training advocate a necessity of SUP by qualified and trained professionals [21,22]. However, recommendations for adults typically lack the same emphasis for SUP, irrespective of experience. ...
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Background: The body of resistance training literature appears heavily focused upon investigating efficacy of interventions by dint of most incorporating supervision (SUP). Authors have suggested that a lack of SUP within strength training results in inadequate workout quality and diminished results yet, since many people choose to perform resistance training unsupervised (UNSUP), it seems important to understand effectiveness of resistance training under such ecologically valid conditions. That is, the extent to which SUP might impact adaptation. Objective: To collectively explore the effects of SUP upon performance/function and body composition outcomes. Design: Exploratory systematic review and meta-analysis. Search and Inclusion: A systematic literature search using a Boolean search strategy was conducted with PubMed/MEDLINE, Scopus, and CINAHL in December 2020 and was supplemented with additional ‘snowballing’ searches. To be included in our analysis, studies had to be experimental trials including at least one performance/functional measure (e.g., strength, speed, power, function, endurance, and cardiorespiratory fitness) and/or body composition measure (body fat percentage, fat mass, and fat free mass). After search and screening, 12 studies were eligible for inclusion including 301 participants in SUP groups and a further 276 participants in UNSUP groups. Results: The cluster robust main model for all performance/function effects (57 across 12 clusters [median = 4, range = 1-12 effects per cluster]) revealed a small, standardised point estimate favouring SUP, though with relatively poor precision for the interval estimate that ranged from a trivial to a moderate effect favouring SUP (0.28 [95%CI = 0.02 to 0.55]). For sub-grouped outcome types there was very poor precision of robust estimates for speed, power, function, and endurance, with all ranging from large effects supporting UNSUP to large effects supporting SUP. However, for strength there was a small, standardised point estimate favouring SUP though with moderate precision for the interval estimate that ranged from a trivial effect favouring SUP to a moderate effect favouring SUP (0.40 [95%CI = 0.06 to 0.74]). The cluster robust main model for all body composition effects (18 across 6 clusters [median = 3, range = 1-6 effects per cluster]) revealed a trivial standardised point estimate favouring SUP that was relatively precise in the interval estimate ranging only trivial effects in either direction (0.07 [95%CI = -0.01 to 0.15]). Conclusions: The results of the present systematic review and exploratory meta-analysis suggest that, broadly speaking, SUP resistance training might produce a small effect on increases in performance/function, most likely in strength, compared to UNSUP, and has little to no impact on body composition outcomes. However, the lack of role and purpose within supervision as well as the lack of parity in UNSUP exercise interventions make providing a conclusive and overarching recommendation difficult.
... As a result, developing appropriate levels of strength is a goal for many population groups and this can be achieved through resistance training programs (RT) [2]. The effect of manipulating RT variables on hypertrophy and muscle strength levels is widely studied [3][4][5][6]. ...
... Prior to the beginning of the study, all volunteers went through a week of adaptation to the exercises proposed and used in this research. Twice times in the adaptation week the volunteers perform three sets of [8][9][10][11][12] repetitions with a light load (4)(5) in the OMNI-RES scale of effort perception [20,21]. ...
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PurposeThe study aimed to evaluate the acute effect of stretching prior to a resistance training (RT) session on morphological, functional, and activation indicators of skeletal muscle.Methods10 men (19.80 ± 1.48 years), were allocated to two experimental conditions: RT protocol (PRT), who performed 4 sets of 6–12 repetitions of the knee extension exercise, at 70% of the maximum dynamic strength; and stretching + RT protocol (PSRT), which performed 3 series of passive stretching for 30 s, for femoral quadriceps muscles (knee flexion), followed by the same protocol performed on the PRT. Perimeter and skinfold of the thigh, maximum isometric force, 1RM and muscle power at 40%, 60%, and 80% of 1RM and electromyography signal of rectus femoris, vastus lateralis, and vastus medialis were evaluated.ResultsNo differences were found for the baseline values of any variable in the two experimental conditions (p > 0.05). There were no significant differences between the two experimental conditions for anthropometric variables (p > 0.05), for the different manifestations of strength evaluated (p > 0.05) and for the muscle activation of the different muscles evaluated (p > 0.05).Conclusion Stretching prior to RT does not decrease strength, does not alter muscle activation, volume and internal training load, when compared to the same protocol, without performing previous stretching.
... Moreover, we extend the current knowledge by analysing multiple potential moderators of changes in muscle strength and mass. Previous studies focussed on single moderators, as loads (Schoenfeld et al., 2017), repetition duration (Schoenfeld et al., 2015), weekly frequencies Schoenfeld et al., 2019) and rest intervals (Grgic, Schoenfeld, Skrepnik et al., 2018), or periodisation (Williams et al., 2017), which may lead to misinterpretation as RT factors have mutual influence. We found only two meta-analyses examining the effects of multiple RT factors on strength (Rhea et al., 2003) and muscle mass (Benito et al., 2020). ...
... A greater training frequency also influenced the hypertrophic responses of this age group. Prior meta-analyses with mixed populations suggested that when RT is volume-equated, there would be no significant effect of RT frequency on strength gains, whereas a slight favouring effect of weekly frequency seems to occur in non-volume equated RT for strength Ralston et al., 2018) or hypertrophy (Schoenfeld et al., 2019). were the only to perform an analysis stratified according to age subgroups -a significant effect of training frequency was detected in young adults, but not among middle-aged and older adults. ...
Article
This meta-analysis investigated the role of resistance training (RT) moderators on strength and muscle mass gains in untrained young (YG) and older (OG) adults. Electronic databases were searched for randomised controlled trials simultaneously assessing muscle strength and mass. Effect sizes (ES) reflecting improvements in strength and muscle mass were found for all moderators in YG and OG (ES 0.25- to 1.72;p < 0.05), excepting muscle mass in YG after RT was performed with <3 sets/exercise. Strength gains (p < 0.001) were greater in non-periodised vs. periodised RT in YG (ES 1.72 vs. 1.05) and OG (1.40 vs. 0.74). ES in OG was greater (p < 0.04) when RT included non-failure vs. failure repetitions (1.35 vs. 0.96), 3 vs. >3 sets/exercise (1.30 vs. 0.90), ≥3 vs. <3 days/week (1.70 vs. 0.78), and ≥12 vs. <12 weeks (1.48 vs. 0.92). Amoderating effect of RT factors on muscle mass was not detected in YG, while greater ES was found in OG for RT with ≥3 vs. <3 days/week (0.50 vs. 0.25). Concluding, different combinations of RT factors improved strength and muscle mass in YG and OG. In OG, this was favoured by greater frequency and duration, although hampered by excessive volume.
... Distinct manipulations of RT variables with same total load lifted (TLL) have been shown to elicit a similar increment in strength and muscle hypertrophy (3, 5,19,31). Additionally, protocols consisting of higher (80% 1RM) vs. moderate intensity (60% 1RM) seem to induce a similar hypertrophic adaptation within volume-equated conditions (19). ...
... This result can be explained by the higher TLL and mechanical stress experienced during this intervention cycle. Indeed, a larger increase in muscle hypertrophy has been described as a result of performing training cycles with a higher TLL, independently of the manipulation of others training variables (e.g., intensity, frequency, rest) (4, 5,13,29,30,31,32). ...
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The aim of the present study was to assess the chronic effects of different order of resistance training cycles on strength and muscle thickness of recreationally resistance-trained men. The study sample was composed of 16 healthy men (age: 25.0 ± 3.8 years, height: 1.77 ± 7.6 cm, total body mass: 81.7 ± 10.4 kg, RT experience: 4.6 ± 0.7 years, relative bench press one repetition maximum: 1.2 ± 0.1, relative squat one-repetition maximum: 1.5 ± 0.2). According to baseline maximal strength, participants were allocated in one of the following groups: Maximal Strength-Strength Endurance (MS-SE) (six weeks of a maximal strength cycle followed by six weeks of a strength endurance cycle); Strength Endurance -Maximal Strength (MS-SE) (six weeks of a strength endurance cycle followed by six weeks of a maximal strength cycle). The following measurements were performed in the pre and post intervention periods: one-repetition maximum (1RM) on parallel back squat and bench press exercises, muscle thickness evaluation of biceps brachialis (MTBB), triceps brachialis (MTTB), and vastus lateralis (MTVL) by ultrasonography. Total load lifted (TLL) and Internal training load (ITL) were also assessed. Both groups presented significant increases in bench press (MS-SE p = 0.001, SE-MS p = 0.003) and half squat (MS-SE p = 0.004, SE-MS p = 0.001) 1RM, MTBB (MS-SE p = 0.020, SE-MS p = 0.005) and MTTB (MS-SE p = 0.001, SE-MS p = 0.001). For MTVL, a significant increase was observed only for MS-SE group (MS-SE p = 0.032, SE-MS p = 0.143). No significant difference between groups was observed for any strength or morphological outcomes. In conclusion, both MS-SE and SE-MS training cycles are effective strategies to enhance resistance training adaptations in trained men.
... Strength and muscle hypertrophy are directly related to the variable load manipulation model of training, that includes: sets, rests, repetitions, exercises, speed, amplitude and weekly frequency of sessions. 1,2 Besides these total load components, there were developed some manipulation strategies of training variables that were named ST methods, used mainly by trained individuals who aim to potentialize results. 3 Some of these methods increase training density, which means to train with great volume and intensity in a relatively short time. ...
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Strength training is an integral part of training programs for aesthetics and sports performance. Although experiments compare the responses of some methods, there is a lack of studies that analyze the time of execution, the recovery and perceptions of pain and exertion. The aim of the present study was to evaluate and compare the metabolic and physiological responses of traditional, drop set and blood flow restriction training. The sample consisted of 16 trained men aged 32 ± 10,5 and minimum of 3 years of continuous and regular practice of ST. Data were collected in 4 days, being the first one assigned to maximum load testing and the following 3 days we analyzed randomly the drop set, blood flow restriction and traditional training methods. Blood lactate was analyzed after the training session. Pre and post intervention arm circumference, heart rate and total time, perceived pain and exertion rating scales, repetition and total volumes. Results showed no significant difference on repetitions number between blood flow restriction and drop set methods but total volume and time were significantly higher on drop set. The highest blood lactate value was found on drop set despite the other methods also show high values. Blood flow restriction and drop set showed significant difference regarding to traditional method on post exercise subjective exertion rating scale, a fact that relates with the highest total volume, mostly on drop set.
... Recent reviews and meta-analyzes [2,[25][26][27] suggest that there is no significant effect of training frequency on either strength performance or muscle hypertrophy when TTV is equalized. However, the results of several studies in these meta-analyzes may have been affected by the large inter-subject variability when different RT frequencies are compared [28]. ...
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Several studies comparing resistance training (RT) frequencies may have been affected by the large between-subject variability. This study aimed to compare the changes in lower limbs maximal dynamic strength (1RM) and quadriceps femoris cross-sectional area (CSA) after a RT with different weekly frequencies in strength-trained individuals using a within-subject design. Twenty-four men participated in a 9-week RT program, being randomly divided into two conditions: resistance training with equalized total training volume (RTEV) and with unequalized total training volume (RTUV). The RT protocol used the unilateral leg press 45° exercise and each subject's lower limb executed one of the proposed frequencies (one and three times/week). All conditions effectively increased 1RM and CSA (p<0.001); however, no significant differences were observed in the values of 1RM (p = 0.454) and CSA (p = 0.310) between the RT frequencies in the RTEV and RTUV conditions. Therefore, RT performed three times a week showed similar increases in 1RM and CSA to the program performed once a week, regardless of training volume equalization. Nevertheless, when the higher RT frequency allowed the application of a greater TTV (i.e., RTUV), higher effect size (ES) values (0.51 and 0.63, 1RM and CSA, respectively) were observed for the adaptations.
... However, the effect of BFR on other important aspects in ACLR rehabilitation, such as physical function and pain, has not been studied. Also, the effectiveness of BFR for stimulating muscle strength and hypertrophy during rehabilitation after ACLR has not been directly compared with high-load exercises in the preoperative period with follow-up in the first 3 months (5)(6)(7)(8)(9). ...
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Background: Muscle mass loss occurs following anterior cruciate ligament reconstruction surgery. Objective: To compare the gain in muscle strength in the quadriceps and hamstring muscles in patients following anterior cruciate ligament reconstruction surgery, using exercises with and without blood flow restriction. Methods: The isometric muscle strength of subjects' knee extension and flexion was evaluated using a digital hand dynamometer, and the physical function of the knee was evaluated using the Lysholm, Knee and Osteoarthritis Outcome Score, and International Knee Documentation Committee questionnaires. Results: Statistical differences were observed in the quadriceps, with an increase in muscle strength (p < 0.01) after 12 weeks, and in the hamstrings (p < 0.01) after 8 and 12 weeks. There was a significant increase in the Lysholm questionnaire score (p < 0.01) after 8 and 12 weeks, a decrease in the Knee and Osteoarthritis Outcome Score pain questionnaire (p < 0.01) after 4 weeks, symptoms and daily activities (p < 0.01) after 8 and 12 weeks, quality of life (p < 0.01) after 12 weeks, and an increase in the International Knee Documentation Committee questionnaire score (p < 0.01) after 8 and 12 weeks. Conclusion: After anterior cruciate ligament surgery, exercises with blood flow restriction proved more efficient for improving the muscle strength of the quadriceps and hamstrings, and the physical function of the knee.
... Table 2 shows the comparison of the Tc and Td values of the rectus femoris (RF) before and after the three groups of exercises. 10 The comparison of Tr and Ts values before and after the three groups of exercises is shown in Table 3 (P<0.05). Delay time, contraction time, maintenance time, and relaxation time all increased. ...
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Introduction Athletes’ muscles can be weakened by fatigue caused by excessive activity. This limitation compromises their functional capacity and professional performance. The competition's performance correlates positively with muscular quality of function. The changes analysis caused by different athletic activities in muscle contraction by noninvasive tensiomyography reflects the functional state of the muscles. Still, no experiments are adapted to verify the fatigue risk level. Objective Verify the possible relationship between exercise and neuromuscular fatigue using noninvasive tensiomyography. Methods 90 athletes were randomly selected in weightlifting, badminton, and athletics sports. Maximum radial displacement, contraction, delay, duration, and relaxation time indices were collected. Muscle fatigue detection was based on the empirical mode decomposition modeling method with the Rogers sensitivity fluctuation rate. All values were collected in the rectus femoris muscle before and after the exercises. They were statistically treated and compared (P<0.05). Results All athletes showed a decline in maximum radial displacement values after exercise. It reveals that their muscles are in a considerable state of tension, especially in the track and field group (from 8.57±3.42mm to 5.43±2.14mm). However, the slightest change in delay time was observed in the weightlifting group (16.21±4.15ms initial versus 18.34±3.27ms final). Conclusion Through tensiomyography technology, it is possible to obtain a relationship between exercise and neuromuscular fatigue, analyzing the physical activity effects in a noninvasive way. Evidence Level II; Therapeutic Studies - Investigating the result. Keywords: Sports; Athletic Injuries; Electrodiagnosis; Muscular Fatigue
... Then, this treatment option requires further investigation in order to re ne the protocols related to cuff pressure, exercise dosage and duration, and consequently, enable a better execution of the technique. 5,6,7,8,9 Therefore, the aim of the present study is to evaluate the intensity of muscle strength gain between exercises with and without occlusion in the quadriceps and hamstring muscles in the postoperative period of the anterior cruciate ligament. ...
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BACKGROUND The anterior cruciate ligament (ACL) reconstruction surgery takes the patient through a period where muscle mass loss occurs. The blood flow restriction combined with strengthening exercises can be an alternative to improve the muscle strength of the quadriceps and hamstrings in the postoperative period of ACL reconstruction. Objective Compare the gain in muscle strength between exercises with and without occlusion in the quadriceps and hamstring muscles in the postoperative period of reconstruction of the anterior cruciate ligament. Methods This is a randomized, prospective, longitudinal clinical trial, parallel, analytical, experimental type, with random allocation.The study included the participation of postoperative patients, with reconstruction of the anterior cruciate ligament. The isometric muscle strength of knee extension and flexion was evaluated using a digital hand dynamometer and the physical function of the knee, using the Lysholm, KOOS and IKDC questionnaires in the pre -operative and after 4, 8 and 12 weeks. All patients signed a written informed consent form prior to the start of the study Results After comparing the rehabilitation of the groups, a statistical difference was observed in quadriceps muscle strength (p <0.01) after 12 weeks and hamstrings (p <0.01) after 8 and 12 weeks in the injured legs. In the analysis of the participants' physical function, there was a significant difference in the Lysholm questionnaire (p <0.01) after 8 and 12 weeks, in the KOOS pain questionnaire (p <0.01) after 4 weeks, symptoms and daily activities (p <0, 01) after 8 and 12 weeks, quality of life (p <0.01) after 12 weeks, and in the IKDC questionnaire (p <0.01) after 8 and 12 weeks. Conclusion The blood flow restriction has proved to be efficient for improving muscle strength of the quadriceps, hamstrings and physical function of the knee after reconstruction of the anterior cruciate ligament in early rehabilitation.
... 21 compared two different training frequencies; three versus six times a week, with the same training volume in bench press and squat resistance exercises, and reported that the magnitude of increase in muscle thickness of triceps brachii (more than 10%) and rectus femoris (more than 5%) and vastus medialis (more than 10%) muscles after 6 weeks of the training was similar between the different frequency programs. Schoenfeld et al. 22 reported in their systematic review and meta-analysis article that weekly resistance training frequency did not affect muscle hypertrophy significantly when training volume was equated. These may explain the similar increases in MT between the 6 × 5 and 30 × 1 groups. ...
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Our previous study found that one maximal voluntary eccentric contraction (MVC‐ECC) performed daily for five days a week for four weeks increased MVC‐ECC, isometric (MVC‐ISO), and concentric contraction (MVC‐CON) torque of the elbow flexors more than 10%. The present study investigated the effects of six maximal voluntary eccentric contractions on the MVC torques and biceps brachii and brachialis muscle thickness (MT). Thirty‐six healthy young adults were placed to one of the three groups (N=12 per group); the 6×1 group that performed one set of six contractions once a week, the 6×5 group that performed one set of six contractions a day for 5 days a week, and the 30×1 group that performed five sets of six contractions a day in a week. The training duration was 4 weeks for all groups, and changes in MVC‐ECC, MVC‐CON and MVC‐ISO torque, and MT before and after the 4‐week training were compared among the groups. The 6×1 group did not show significant changes in muscle strength and MT. Significant (p>0.05) increases in MVC‐ECC (13.5±11.5%), MVC‐ISO (9.3±5.5%), MVC‐CON torque (11.1±7.4%) were evident for the 6×5 group only, and increases in MT were found for the 6×5 (10.4±4.4%) and 30×1 (8.0±5.8%) groups without a significant difference. These results suggest that performing a small number of eccentric contractions five days a week is more effective for increasing muscle strength than performing a larger volume of eccentric contractions once a week. However, it appears that training volume is a factor for muscle hypertrophy in a short‐term training.
... Therefore, understanding what the resistance training volume is made of appears critical to overload, equalize or underload the stimuli along the training period, given that volume seems a key factor in resistance training [7,8]. Such variables might be classified as betweensession, for example the time between two consecutive sessions or even two consecutive identical sessions, typical in split-routine programs [9], or as within-session, for example, the order of exercise that seems to enhance the strength but not the hypertrophic gains [10]. Moreover, between-exercise variables may still be listed, as for example the type of load (e.g. ...
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Manipulating resistance training variables is crucial to plan the induced stimuli correctly. When reporting the exercise variables in resistance training protocols, sports scientists and practitioners often refer to the load lifted and the total number of repetitions. The present conceptual review explores all within-exercise variables that may influence the strength and hypertrophic gains, and the changes in muscle architecture. Together with the (1) load and (2) the number of repetitions, (3) performing repetitions to failure or not to failure, (4) the displacement of the load or the range of movement (full or partial), (5) the portion of the partial movement to identify the muscle length at which the exercise is performed, (6) the total time under tension, the duration of each phase and the position of the two isometric phases, (7) whether the concentric, eccentric or concentric-eccentric phase is performed, (8) the use of internal or external focus and (9) the inter-set rest may all have repercussions on the adaptations induced by each resistance exercise. Manipulating one or more variable allows to increase, equalize or decrease the stimuli related to each exercise. Sports scientists and practitioners are invited to list all aforementioned variables for each exercise when reporting resistance training protocols.
... Training frequency is an often overlooked variable of exercise prescription [23]. While studies and systematic reviews have been conducted on RT frequency [24][25][26][27][28], current recommendations for improving muscular adaptation are based on inferences from a limited body of evidence with inherent major limitations that makes the interpretation and applicability of results difficult to implement, such as small sample sizes [26,27,29]. Moreover, none of these studies reported changes in MQ, and a clear minimal dose of RT in adolescent individuals is unknown. ...
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Previous research has established the role of resistance training (RT) on muscle function in adolescents, but a lack of evidence to optimize RT for enhancing muscle quality (MQ) exists. This study examined whether RT frequency is associated with MQ in a nationally representative adolescent cohort. A total of 605 adolescents (12–15 year) in NHANES were stratified based on RT frequency. MQ was calculated as combined handgrip strength divided by arm lean mass (via dual-energy X-ray absorptiometry). Analysis of covariance was adjusted for sex, race/ethnicity, and arm fat percentage; p < 0.05 was considered significant. RT frequency was associated with MQ for 2–7 day/week but not 1 day/week. When no RT was compared to 1–2 and 3–7 day/week, associations were present for 3–7 day/week but not 1–2 day/week. When comparing no RT to 1–4 and 5–7 days/week, associations existed for 5–7 day/week but not 1–4 day/week. Next, no RT was compared to 1, 2–3, and 4–7 day/week; associations were found for 4–7 day/week, while 2–3 days/wk had a borderline association (p = 0.06); there were no associations for 1 day/week. Finally, no RT was compared to 1, 2, 3, 4, and 5–7 day/week; associations were present for all except 1 and 3 day/week. These prospective data suggest a minimum RT frequency of 2 day/week is associated with MQ in adolescents as indicated by the lack of differences in MQ between 1 day/week RT versus no RT.
... The management of resistance training variables for adaptations is well established within academic literature. Empirical studies and subsequent systematic reviews and/or meta-analyses have considered manipulation of load [1], repetition duration [2], weekly volume [3], frequency [4], exercise order [5], and range of motion [6], among other variables, in an attempt to optimise exerciseinduced adaptations. However, in none of these reviews was training supervision (SUP) discussed as a potentially confounding variable. ...
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Article
Background: Since many people choose to perform resistance training unsupervised, and a lack of supervision within strength training is reported to result in inadequate workout quality, we aimed to compare outcomes for resistance training with and without supervision. Methods: A systematic review and meta-analysis were performed for performance/functional outcomes and/or body composition measurements. Results: 12 studies were included in the review; 301 and 276 participants were in supervised and unsupervised groups, respectively. The main model for all performance/function effects revealed a small, standardised point estimate favouring SUP (0.28 [95%CI = 0.02 to 0.55]). For sub-grouped outcome types, there was very poor precision of robust estimates for speed, power, function, and endurance. However, for strength there was a moderate effect favouring SUP (0.40 [95%CI = 0.06 to 0.74]). The main model for all body composition effects revealed a trivial standardised point estimate favouring SUP (0.07 [95%CI = -0.01 to 0.15]). Conclusions: Supervised resistance training, compared to unsupervised training, might produce a small effect on increases in performance/function, most likely in strength, but has little impact on body composition outcomes.
... Amateur/recreational athletes train 3-4 times per week only (Volpe, 2006), while it is reported that training frequency is an important factor that affects the hypertrophic response (Dankel et al., 2017). Opposing to this, a recent review has reported a strong evidence that training frequency does not significantly impact muscle hypertrophy (Schoenfeld, Grgic, & Krieger, 2018). Taking everything into consideration, we acknowledge the lack of body fat and muscle mass percentage (%) parameters following BMI, as a major limitation in this study. ...
... The correct manipulation of resistance training variables is needed to maximize the increases in muscle mass (Kraemer and Ratamess 2004). When optimizing the resistance training programming aimed to increase muscle hypertrophy, different variables such as volume (Schoenfeld et al. 2017a;Baz-Valle et al. 2018), load/intensity (i.e., % of 1RM) (Schoenfeld et al. 2017b), inter-set rest (Schoenfeld et al. 2016b;Grgic et al. 2017), and frequency (Schoenfeld et al. 2016a(Schoenfeld et al. , 2019b have been reported to produce the maximum hypertrophic response. In fact, resistance training is just a specific training based on programming external variables such as load or exercises selection to generate high mechanical forces by the neuromuscular system against resistance. ...
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Resistance training is frequently performed with the goal of stimulating muscle hypertrophy. Due to the key roles motor unit recruitment and mechanical tension play to induce muscle growth, when programming, the manipulation of the training variables is oriented to provoke the correct stimulus. Although it is known that the nervous system is responsible for the control of motor units and active muscle force, muscle hypertrophy researchers and trainers tend to only focus on the adaptations of the musculotendinous unit and not in the nervous system behaviour. To better guide resistance exercise prescription for muscle hypertrophy and aiming to delve into the mechanisms that maximize this goal, this review provides evidence-based considerations for possible effects of neural behaviour on muscle growth when programming resistance training, and future neurophysiological measurement that should be tested when training to increase muscle mass. Combined information from the neural and muscular structures will allow to understand the exact adaptations of the muscle in response to a given input (neural drive to the muscle). Changes at different levels of the nervous system will affect the control of motor units and mechanical forces during resistance training, thus impacting the potential hypertrophic adaptations. Additionally, this article addresses how neural adaptations and fatigue accumulation that occur when resistance training may influence the hypertrophic response and propose neurophysiological assessments that may improve our understanding of resistance training variables that impact on muscular adaptations.
... Amateur/recreational athletes train 3-4 times per week only (Volpe, 2006), while it is reported that training frequency is an important factor that affects the hypertrophic response (Dankel et al., 2017). Opposing to this, a recent review has reported a strong evidence that training frequency does not significantly impact muscle hypertrophy (Schoenfeld, Grgic, & Krieger, 2018). Taking everything into consideration, we acknowledge the lack of body fat and muscle mass percentage (%) parameters following BMI, as a major limitation in this study. ...
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Practice of sport, exercise or recreational physical activity increase the needs of energy and nutrients. Objectives are: 1) to evaluate BMI; 2) to assess the nutritional status; and 3) to test the association between BMI and KIDMED index. The study is realized on a sample of healthy young participants (N=101), aged 18-35, that do recreational sport activities such as: football (N=24), basketball (N=16), handball (N=15), volleyball (N=20), tennis (N=10), swimming (N=10) and martial arts (N=9). Body composition: height, weight, and BMI, were measured and calculated according to World Health Organization's manual. A 16-item KIDMED questionnaire was used to assess nutritional status. KIDMED index was calculated after the KIDMED questionnaire was administered to all participants. Spearman's rank correlation coefficient was applied to test the association between BMI and KIDMED index. We have assessed an optimal diet-medium quality, in physically active population that is involved in recreational sport such as: football, basketball, handball, volleyball, tennis, swimming and martial arts, and a normal healthy weight category based on BMI classification criteria of World Health Organization. In addition, we have found a weak positive association between BMI and KIDMED index in physically active population, that was not statistically significant. The outcome of the study indicates that most of the people that are regularly involved in physical activity have a decent nutritional awareness, as a result of the nutritional counseling they get from their coaches. It seems that recreational collective activities and sports, besides allowing people to gain knowledge about healthy eating skills and nutritional habits, also encourage them to bring the required changes in their diets. The impact of physical activity may be a promising area for future promotion of nutrition and health.
... However, although subjects could not be randomly distributed between the intervention groups, no significant between-group differences were detected at baseline; (b) the secondary analysis also limited the number of subjects available for analysis, resulting in a small sample size; (c) although both groups performed the same number of RT sessions, the difference in training frequency could be considered a limitation. However, meta-analytic data show no difference in muscle strength and muscle mass increases between frequencies of 23 vs. 33 per week, especially when VL is matched (7,20); (d) CSA increase was assessed only on the vastus lateralis muscle. Considering the involvement of the rectus femoris in leg extension, the lack of data on this muscle can also be considered a limitation; (e) finally, our data are limited to 24 training sessions of a single exercise on previously untrained subjects. ...
... A dose-dependent relationship between the total training volume (TTV) and the magnitude of hypertrophic adaptations has been well established in the literature. 1 Therefore, strategies capable of increasing TTV may be beneficial for chronic hypertrophy. 2 Multi-ingredient pre-workout supplements (MIPS) have grown in popularity in the past decade and are designed to be consumed as an ergogenic aid prior to resistance training to enhance TTV. MIPS typically contain caffeine in addition to antioxidants and amino acids such as betaalanine and betaine anhydrous. ...
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Objective: To analyse the acute effect of betaine supplementation on muscular endurance in weight training practitioners. Design: An experimental, crossover, randomized and double-blind study. Methods: The sample composed of 10 male subjects practicing resistance training (age: 23.71 ± 4.23 years old). Participants performed 2 sessions (i.e., Betaine x Placebo) with 3 sets of repetitions until failure with 70% of 1RM. The participants were provided 3 minutes of recovery between sets and 48 hours between sessions. The 24H food recall was evaluated before each exercise session. Results: There were no significant differences in carbohydrates (p = 0.732), protein (p = 0.684), fat (p = 0.271), or in total energy consumption (p = 0.865). A time effect occurred for the training session (F (2,18) = 54.626, p < 0.0001, η² = 0.859), with a linear reduction in the number of repetitions performed throughout the series for both conditions (1set > 2set > 3set). However, there was no interaction (F (2,18) = 0.625, p= 0.546, η² = 0.065) or condition effect (F(1,9) = 0.045, p = 0.837, η² = 0.005). Conclusion: Acute betaine supplementation had no effect on muscular endurance performance in the bench press.
... However, it is not possible to make inferences in this regard from the current evidence. A meta-analysis conducted by Schoenfeld et al. (2019) concluded that the ST frequency does not meaningfully impact muscle hypertrophy when the volume is equated. Concerning older individuals, recently Pina et al. (2019) found no difference in lean mass response between individuals who trained two or three times a week after a 12-week setsequated ST. ...
... Meta-analytic data of studies that directly compared higher versus lower RT frequencies found similar increases in muscle size in volume-equated programs irrespective of whether muscle groups were trained 1, 2, 3, or 4+ days per week (123). Alternatively, subanalysis of studies whereby volume was not equated showed a small but statistically significant benefit for higher training frequencies up to 3 days per week. ...
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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.
... 1,8,9 The most common parameters used to quantify RT volume are the number of sets performed and/or the volume-load (load lifted multiplied by the number of repetitions). [10][11][12] In this context, different studies-including systematic reviews with meta-analysis-have suggested a positive dose-response relationship between training volume and the increase in muscular strength. 8,9 For example, it was demonstrated that performing higher RT volume (> 5 sets/week per exercise) was more effective than low volume (≤ 5 sets/week per exercise) to increase 1RM strength. ...
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Article
Resistance training (RT) volume is considered a critical variable to induce neuromuscular adaptations (e.g., increased muscle strength). However, emerging findings have allowed us to revisit the role of volume in strength gains. Objectives: In the present study, we seek to present these emerging findings to discuss the role of RT volume in one-repetition maximum (1RM) strength gains and isometric and isokinetic strength. In addition, we propose alternative ways to test whether or not volume plays a determining role in strength adaptation. Design & methods: We reviewed the literature on RT volume and muscle strength. In adittion, we examined the RT literature to provide alternative ways to investigate the effect of volume on changes in strength. Results/conclusions: From the recent findings, we argue that an increase in strength can be achieved through a refined interaction between skill enhancement, regular use of high loads, and neuromuscular fatigue management; these points can be obtained from different RT volumes. From an inquiring point of view, we suggest that future investigations that aim to verify the effects of volume on muscle strength may consider the inclusion of high load sessions (80–100% of 1RM), periodically (e.g., every three or four weeks), in both low and high-volume groups, as well as considering the inclusion of different strength measures (e.g., isokinetic, isometric). We believe that this will help to clarify the nature of the relationship between RT volume and strength adaptations.
... In medicine, a doseresponse relationship exists [6,7], and if considering exercise as medicine, effects on pain and disability can be optimised by manipulating exercise dosage (sets, reps, loads, frequency etc.). Precision prescription of dosage and other variables such as exercise type, speed or order, increases the effectiveness of achieving physiological outcomes of hypertrophy, strength, power, endurance in healthy populations [8][9][10][11][12][13][14][15][16][17]. The effect of manipulating dosage and other exercise variables in neck pain populations on patient-reported outcome measures is less clear [18]. ...
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Background: Chronic non-specific neck pain is highly prevalent, resulting in significant disability. Despite exercise being a mainstay treatment, guidance on optimal exercise and dosage variables is lacking. Combining submaximal effort deep cervical muscles exercise (motor control) and superficial cervical muscles exercise (segmental) reduces chronic non-specific neck pain, but evaluation of optimal exercise and dosage variables is prevented by clinical heterogeneity. Objective: To gain consensus on important motor control and segmental exercise and dosage variables for chronic non-specific neck pain. Methods: An international 3-round e-Delphi study, was conducted with experts in neck pain management (academic and clinical). In round 1, exercise and dosage variables were obtained from expert opinion and clinical trial data, then analysed thematically (two independent researchers) to develop themes and statements. In rounds 2 and 3, participants rated their agreement with statements (1-5 Likert scale). Statement consensus was evaluated using progressively increased a priori criteria using descriptive statistics. Results: Thirty-seven experts participated (10 countries). Twenty-nine responded to round 1 (79%), 26 round 2 (70%) and 24 round 3 (65%). Round 1 generated 79 statements outlining the interacting components of exercise prescription. Following rounds 2 and 3, consensus was achieved for 46 important components of exercise and dosage prescription across 5 themes (clinical reasoning, dosage variables, exercise variables, evaluation criteria and progression) and 2 subthemes (progression criteria and progression variables). Excellent agreement and qualitative data supports exercise prescription complexity and the need for individualised, acceptable, and feasible exercise. Only 37% of important exercise components were generated from clinical trial data. Agreement was highest (88%-96%) for 3 dosage variables: intensity of effort, frequency, and repetitions. Conclusion: Multiple exercise and dosage variables are important, resulting in complex and individualised exercise prescription not found in clinical trials. Future research should use these important variables to prescribe an evidence-informed approach to exercise.
... The similar increases in muscle thickness were in accordance with our hypothesis because training volume has been shown to be the key factor for resistance training-induced hypertrophy (14,38,39). Therefore, the lack of differences between the LVL and HVL could most likely be explained by the equated training volume. ...
Article
Andersen, V, Paulsen, G, Stien, N, Baarholm, M, Seynnes, O, and Saeterbakken, AH. Resistance training with different velocity loss thresholds induce similar changes in strengh and hypertrophy. J Strength Cond Res XX(X): 000-000, 2021-The aim of this study was to compare the effects of 2 velocity-based resistance training programs when performing resistance training with matched training volume. Ten resistance-trained adults volunteered (age, 23 ± 4.3 years; body mass, 68 ± 8.9 kg; and height, 171 ± 8 cm) with a mean resistance training experience of 4.5 years. A within person, between leg design was used. For each subject, the legs were randomly assigned to either low velocity loss (LVL) threshold at 15% or high velocity loss (HVL) threshold at 30% velocity loss. Leg press and leg extension were trained unilaterally twice per week over a period of 9 weeks. Before and after the intervention, both legs were tested in 1 repetition maximum (RM) (kg), maximal voluntary contraction (MVC) (N), rate of force development (N·s-1), average velocity (m·s-1), and power output (W) at 30, 45, 60, and 75% of 1 RM (all in unilateral leg press). Furthermore, muscle thickness (mm) of the vastus lateralis and rectus femoris, pennation angle (°) of the vastus lateralis, and the fascicle length (mm) of the vastus lateralis were measured using ultrasound imaging. The data were analyzed using mixed-design analysis of variance. No differences between the legs in any of the variables were found; however, both low and HVL were effective for increasing 1 RM (ES = 1.25-1.82), MVC (effect size [ES] = 0.42-0.64), power output (ES = 0.31-0.86), and muscle thickness (ES = 0.24-0.51). In conclusion, performing velocity-based resistance training with low and HVL with equal training volume resulted in similar effects in maximal and explosive strength in addition to muscular adaptations.
... Sports Sciences have, however, been overly focused in training variables such as volume and intensity (Bradbury et al., 2020), and sometimes frequency (Schoenfeld et al., 2019), while largely neglecting other dimensions of load (Piggott et al., 2019). Volume and intensity are important load parameters (Mangine et al., 2015), but they provide an incomplete picture. ...
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Load is a multifactorial construct, but usually reduced to parameters of volume and intensity. In the last decades, other constructs have been proposed for assessing load, but also relying on relationships between volume and intensity. For example, Foster's Training Monotony has been used in athletes' load management simply by computing mean weekly load divided by its standard deviation, often multiplied by session rate of perceived exertion. Meanwhile, the Acute to Chronic Workload Ratio (ACWR) has been debated by the sport scientists as a useful monitoring metric and related to so-called injury prevention. None of these models includes parameters that are representative of training specificity, namely load orientation. The aim of this study is to present broader conceptual approaches translated by new indices for assessing Intraweek Training Monotony (ITM) and Acute to Chronic Workload Index (ACWI) while incorporating load orientation, session duration and weekly density (frequency normalized) in addition to parameters related to proxies of external and/or internal load. Our ITM and Foster's Training Monotony were similar in terms of average values, but very different for individualized analysis, illustrating how average values may be deceiving. While Foster's model provided clusters of values, ITM provided more scattered, individualized data. ACWI and ACWR provided very distinct qualitative information, and the two models were uncorrelated. Therefore, the models incorporating training load orientation presented in this study provide distinct and not redundant information when compared to previous models. More importantly, ITM and ACWI are metrics that are compatible to each other and might fit to coaches' monitoring targets in the short and medium terms, respectively. Because our models include several parameters, including load orientation, we contend that might provide a more complete monitoring tool. However, we suggest they are used for intraindividual comparisons and not so strongly for interindividual comparisons.
... Die Trainingshäufigkeit wird im vorliegenden Artikel als Trainingseinheiten je Muskel pro Woche definiert. Derzeitige theoretische Überlegungen sowie aktuelle Untersuchungen deuten darauf hin, dass Trainingsprogramme, bei denen ein Muskel mehr als zweimal pro Woche trainiert wird, effektiver sind als jene mit geringerer Trainingshäufigkeit [14], [15], [16]. Der aktuelle Forschungsstand reicht derzeit jedoch nicht aus, um eine Empfehlung für eine optimale Trainingshäufigkeit zu treffen. ...
Article
The breakdown of skeletal muscles increases with age and is further accelerated in today’s society due to lower physical activity. The skeletal muscles are primarily responsible for the transmission of force and thus for our everyday movement. With the reduction of muscle mass, the execution of everyday movement is continuously hampered and the quality of life can be significantly reduced. However, strength or hypertrophy training can counteract muscle atrophy by slowing down degradation processes and rebuilding skeletal muscles. Nonetheless, training recommendations for hypertrophy training vary considerably. The primary aim of this article, therefore, is to summarize the current state of research and make practical recommendations. The most decisive aspect of hypertrophy training seems to be the setting of regular progressive and exhausting stress stimuli that activate at least one mechanism of action that is responsible for hypertrophic effects. In particular, the variation of the mechano-biological descriptors (training resistance, number of repetitions and sets, rests, etc.) could help to create long-term effective stimuli. There is almost no limit to the number of possible combinations, but these have to be adapted to the level of performance and the resilience of the training person as well as the feasibility in everyday life. As in the motto “many roads lead to Rome,” hypertrophy training does not just entail one specific solution for planning and implementation. It is more essential to perform iterative stress stimuli in different variations in order to generate a hypertrophy effect and consequently counteract the breakdown of the skeletal muscles.
... Both the CRT and TRT groups displayed similar small decreases in body fat percentage and moderate to large increases in thigh and arm circumferences after the training period. Although the changes in limb circumference is a rough way to detect the hypertrophic training effects 28,29 , the average magnitude of the improvement in limb circumferences (+ ~4-10%) in the present study is in line with previous reviews that have addressed the effects of RT with similar durations on site-specific hypertrophic measures in this population 30,31 . Increased limb size could be interpreted as muscle hypertrophy 28,29 , while the present study is not able to make inferences about what physiological adaptations underpin these changes. ...
Article
Background: Providing accommodating resistance with the use of chains (CRT) is a programming technique that may enhance muscle size, strength, and power. However, there is a paucity of studies comparing the responses to CRT and traditional resistance training (TRT) approaches. This study aimed to examine the effects of 8 weeks of CRT and TRT on muscular adaptations in young recreationally-trained men. Methods: Thirty men (26 ± 4 y) volunteered to participate in the present study and were randomly assigned to either CRT (n = 10), TRT (n = 10), or a non-exercise control group (CG, n = 10). A resistancetraining program (3-4 sets, ~8-12 repetitions at 65-80% of 1RM) was performed three times a week for 8 weeks. Percentage body fat, arm and thigh circumferences, 1RM and endurance (number of repetitions to failure 60% of 1RM) strength tests in the back squat and bench press exercises, and vertical jump power were assessed before and after the intervention. Results: Following the intervention, both training groups demonstrated improvements in strength compared to CG, where greater gains were observed for CRT (e.g., bench press 1RM: CRT=28%; TRT=19% / back squat endurance: CRT=8%; TRT=2%). Conclusions: The use of chains during resistance training may promote greater gains in strength in young men.
... This may have implications for the results heterogeneities of the studies, as not all EX protocols were performed with high load resistance training. In addition, several other training variables can influence responses, such as recovery time between sets [113], frequency [114] and training volume [115]. These variables go beyond the ability to be analyzed quantitatively by our study. ...
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Sarcopenia, cachexia, and atrophy due to inactivity and disease states are characterized by a loss of skeletal muscle mass, often accompanied by reduced levels of anabolic hormones (e.g. testosterone). These conditions are associated with an increase in mortality, hospitalization and worsening in quality of life. Both physical exercise (EX) and anabolic-androgenic steroid (AAS) administration can improve the prognosis of patients as they increase physical functionality. However, there is a gap in the literature as to the impact of these therapies on the gains in strength and muscle mass and their implications for patient safety. Accordingly, we performed a random-effects meta-analysis to elucidate the effects of AAS and/or EX interventions on lean body mass (LBM) and muscle strength in conditions involving muscle loss. A systematic search for relevant clinical trials was conducted in MEDLINE, EMBASE, SCOPUS, Web of Science, and SPORTDiscus. Comparisons included AAS vs. Control, EX vs. Control, AAS vs. EX, AAS + EX vs. AAS and AAS + EX vs. EX. A total of 1114 individuals were analyzed. AAS increased LBM (effect size [ES]: 0.46; 95% CI: 0.25, 0.68, P = 0.00) and muscle strength (ES: 0.31; 95% CI: 0.08, 0.53, P = 0.01) when compared to a control group. EX promoted an increase in muscular strength (ES: 0.89; 95% CI: 0.53, 1.25, P = 0.00), with no effect on LBM when compared to the control group (ES: 0.15; 95% CI:-0.07, 0.38, P = 0.17). AAS did not demonstrate statistically significant differences when compared to EX for LBM and muscle strength. The combination of EX + AAS promoted a greater increase in LBM and muscular strength when compared to AAS or EX in isolation. Qualitatively, AAS administration had relatively few side effects. Significant heterogeneity was found in some analyses, which may be explained by the use of different AAS types and EX protocols. Our findings suggest that AAS administration in cachectic and sarcopenic conditions may be a viable interventional strategy to enhance muscle function when exercise is not a possible approach. Moreover, combining AAS with exercise may enhance positive outcomes in this population.
Article
Background: Massive rotator cuff tears (MRCT) account for a substantial fraction of tears above the age of 60 years. However, there are no clear criteria for prescription parameters within therapeutic exercise treatments. The aim of this study was to evaluate the effects and characteristics of therapeutic exercise treatments in patients with MRCT. Methods: A systematic search was conducted in MEDLINE/PubMed, Web of Science, SPORTDiscus, SciELO, Scopus and EMBASE from inception to August 2022. Studies were included if they evaluated the effects of exercise on patients with MRCT. The risk of bias was evaluated and the Consensus on Exercise Reporting Template (CERT) was also used. A narrative synthesis without meta-analysis was performed. Results: One randomized controlled trial, two non-randomized studies, six non-controlled studies, one case series and four retrospective studies were included. They ranged from serious to moderate risk of bias. The CERT reflected a poor description of the exercise programmes. Studies showed a pattern of improvements in most patient-reported outcome measures (PROM) surpassing the MCID, and active elevation range of motion. Conclusions: There is limited evidence that exercise and co-interventions are effective in the management of some patients with MRCT, based on a systematic review without meta-analysis. Future research should improve content reporting. Level of evidence: IV.
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Objective: The present study aimed to verify if young adult males who aimed to improve their strength or attain muscle hypertrophy trained in agreement with the current strength and conditioning guidelines. Methods: Four hundred and fourteen subjects aged 18-25 with less than one year of strength training experience and whose training goal was to increase their strength or develop muscle hypertrophy were finally included in this research. They were surveyed through an 18-item self-administered questionnaire to verify whether their strength training practices met the current strength training guidelines. Results: Overall, more than 50% of the respondents did not follow the current strength and conditioning recommendations related to muscle action, number of sets, training structure, type of resistance, training to failure, and training supervision. Only slightly more than 50% of them did not train in agreement with the recommendations regarding exercise selection, number of repetitions, and weekly training frequency. The level of compliance with the training objectives of the respondents who followed the current strength and conditioning guidelines related to exercise selection, rest, speed, type of resistance, and training supervision was higher than specific cohorts who did not. Conclusion: Training in agreement with the current strength and conditioning guidelines would ensure that young adult males with less than one year of strength training experience attain their training objectives to a greater extend. Subjects who practice strength training should follow those strength and conditioning guidelines to avoid limiting future adaptations and increase the variability of their training programs, thus preventing workout plateau and fostering motivation.
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The purpose of this study was to calculate the effects of exercise programs on phase angle (PhA) in older people. A systematic review was undertaken in multiple electronic databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement guidelines for the purposes of selecting randomized controlled trials that measured the effects of the exercise programs on PhA in older adults on 31 March 2022. We carried out a random-effect meta-analysis for the effects of exercise programs on PhA. Additionally, we analysed the differences between subgroups in terms of weekly frequency, number of sets and repetitions, and duration of interventions. Studies were methodological assessed through the PEDro scale where one had excellent, ten had good, and three had poor methodological quality. For the purposes of the study, fourteen studies met the criteria for inclusion. However, four studies did not have enough information to be included in the quantitative analysis. The remaining ten articles revealed moderate effects on PhA in favour of intervention groups (p=0.009, SMD=0.72 [0.46–0.99], I²=54%). The meta-analysis also showed that interventions lasting twelve weeks are more successful in generating positive effects on PhA as opposed to eight weeks (SMD's=0.79 vs. 0.64, respectively). These results indicate that resistance training (RT) is an effective and safe to improve PhA in the older people, especially through RT programs lasting from eight to twelve weeks. A novel finding of this study was that RT is the most used type of exercise by authors when assessing the PhA in older adults.
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International Journal of Exercise Science 15(4): 709-720, 2022. The aim of the present study was to investigate the effects of distinct resistance training frequencies with equated-volume conditions in morphological and functional adaptations of the patellar tendon. Twenty-seven recreationally resistance-trained subjects (men [n=17] and women [n=10]) (age: 20.8 ± 1.9 years [range 18 to 25 years]; height: 1.73 ± 9.8 cm; total body mass = 73.2 ± 11.7 kg; previous RT experience = 3.3 ± 1.6 years) volunteered to participate in this study. A total of 16 training sessions were performed during the study period. Each subject's leg was randomly allocated to one of the following training protocols: 2 training sessions/week (2x) or 4 training sessions/week (4x). Measurements of tendon cross sectional area (CSA) and length were performed through ultrasound imaging. One repetition maximum test was performed to assess patellar tendon force (PTF) unilaterally. For CSA (2x: Δ=-1.3%; 4x: Δ=-0.9%), and length (2x: Δ=-0.4%; 4x: Δ= 1.2%), no significant differences were observed within or between conditions (all p > 0.05). For PTF, a significant difference was observed between conditions (mean difference = 0.05 [-125 to 224] p= 0.001). In conclusion, the leg extension exercise performed 2 vs 4x/week induces similar patellar tendon morphological responses. However, the increase in force seems to be enhanced by a lower weekly training frequency associated with a longer intervention period.
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Article
International Journal of Exercise Science 15(4): 709-720, 2022. The aim of the present study was to investigate the effects of distinct resistance training frequencies with equated-volume conditions in morphological and functional adaptations of the patellar tendon. Twenty-seven recreationally resistance-trained subjects (men [n=17] and women [n=10]) (age: 20.8 ± 1.9 years [range 18 to 25 years]; height: 1.73 ± 9.8 cm; total body mass = 73.2 ± 11.7 kg; previous RT experience = 3.3 ± 1.6 years) volunteered to participate in this study. A total of 16 training sessions were performed during the study period. Each subject's leg was randomly allocated to one of the following training protocols: 2 training sessions/week (2x) or 4 training sessions/week (4x). Measurements of tendon cross sectional area (CSA) and length were performed through ultrasound imaging. One repetition maximum test was performed to assess patellar tendon force (PTF) unilaterally. For CSA (2x: Δ=-1.3%; 4x: Δ=-0.9%), and length (2x: Δ=-0.4%; 4x: Δ= 1.2%), no significant differences were observed within or between conditions (all p > 0.05). For PTF, a significant difference was observed between conditions (mean difference = 0.05 [-125 to 224] p= 0.001). In conclusion, the leg extension exercise performed 2 vs 4x/week induces similar patellar tendon morphological responses. However, the increase in force seems to be enhanced by a lower weekly training frequency associated with a longer intervention period.
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Chapter
For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.
Article
Anterior cruciate ligament (ACL) injury and reconstructive surgery is known to cause long term negative impacts on quadriceps muscle size. With the known link between reduced muscle size and the health and functioning of the knee joint, it is important rehabilitation programs aim to restore quadriceps mass as safely and quickly as possible. However, a comprehensive review of interventions investigating the impact of exercise interventions on quadriceps muscle size in ACL reconstructed individuals has yet to be undertaken. Therefore, this article systematically reviews the evidence investigating training interventions that aim to improve quadriceps size in ACL reconstructed individuals. Systematic review A literature search was performed in Medline, SPORTdiscus, Cinahl and Web of Science. Observational and experimental studies investigating training interventions impact on quadriceps muscle size in ACL reconstructed individuals were included. Risk of bias assessment (Downs and Black) was completed on included studies. Data was extracted and a best evidence synthesis was undertaken. 718 articles were returned in the initial search, following screening six articles were included in this review. Results from the best evidence synthesis suggest there is moderate evidence for eccentrically biased training to increase quadriceps size. Both traditional resistance training and blood flow restriction training showed conflicting results for improving quadriceps size. However, the results for traditional resistance training and blood flow restriction training may have been limited by differing imaging methods across included studies. This review highlights the positive changes in quadriceps size seen following traditional, eccentrically biased and blood flow restriction exercise interventions in ACL reconstructed limbs, despite the limited number of studies. Further work is needed to identify and optimise best practice hypertrophic training in these individuals.
Article
Räntilä, A, Ahtiainen, JP, Avela, J, Restuccia, J, Kidgell, DJ, and Häkkinen, K. High responders to hypertrophic strength training also tend to lose more muscle mass and strength during detraining than low responders. J Strength Cond Res 35(6): 1500-1511, 2021-This study investigated differences in individual responses to muscle hypertrophy during strength training and detraining. Ten weeks of resistance training was followed by 6 weeks of detraining in men (n = 24). Bilateral leg press (LP) one-repetition maximum (1RM) and maximal electromyography (EMGs) of vastus lateralis (VL) and vastus medialis, maximal voluntary activation (VA), transcranial magnetic stimulation for corticospinal excitability (CE), cross-sectional area of VL (VLCSA), selected serum hormone concentrations were measured before and repeatedly during training and detraining. In the total group, VLCSA increased by 10.7% (p = 0.025) and LP 1RM by 16.3% (p < 0.0001) after training. The subjects were split into 3 groups according to increases in VLCSA: high responders (HR) > 15% (n = 10), medium responders (MR) 15-4.5% (n = 7), and low responders (LR) < 4.5% (n = 7). Vastus lateralis CSA in HR and MR increased statistically significantly from pre to posttraining but not in LR. Only HR increased LP 1RM statistically significantly from pre to post. Maximal EMG activity increased 21.3 ± 22.9% from pre- to posttraining for the total group (p = 0.009) and for MR (p < 0.001). No significant changes occurred in VA and CE or serum hormone concentrations. During detraining, HR showed a decrease of -10.5% in VLCSA, whereas MR and LR did not. None of the subgroups decreased maximal strength during the first 3 weeks of detraining, whereas HR showed a slight (by 2.5%) rebound in strength. The present results suggest that strength gains and muscle activation adaptations may take place faster in HR and decrease also faster compared with other subgroups during detraining.
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Thesis
Summary of the doctoral thesis Introduction: In many sports, strength is considered an important basis for performance. One factor affecting strength is muscle mass. Therefore, it may be necessary to increase muscle mass in athletes through resistance training. However, the most effective strategy to gain muscle mass has not yet been clearly identified. Many methods used in practice are based on anecdotal evidence rather than empirical data. For this reason, different approaches to hypertrophy training were examined in this thesis based on three studies. The methods and most important results of these studies are summarized in the following. Methods: In the first study, adolescent American football players completed a 12-week resistance training program with three total-body training sessions per week using either Block Periodization (BLOCK) or Daily Undulating Periodization (DUP). The aim was to investigate the effects of the different periodization strategies on muscle mass and athletic performance. The second study assessed the impact of a three-week detraining period (DTR) on anthropometric measures and sport performance. In a third study, highly trained male subjects completed a six-week low-intensity calf resistance training intervention either without (noBFR) or with blood flow restriction (BFR). Before and after the intervention, 1-RM calf raise, calf volume, muscle thickness of the gastrocnemius, and leg stiffness were recorded. Results: At the end of the first intervention, both periodization groups showed significantly higher muscle mass and thickness, as well as athletic performance without differences between groups. Following DTR, fat mass increased significantly, and fat-free mass was reduced. All other measures were unchanged after DTR. Both BFR and NoBFR training resulted in significant increases in 1-RM and muscle thickness without differences between groups. Calf volume and leg stiffness remained unchanged in both conditions. Conclusions: In adolescent American football players, the structure of periodization does not appear to have any effect on muscle growth. Furthermore, a three weeks DTR does not result in negative effects. Both results provide new insights that can be helpful when creating training programs as well as for planning training-free periods. The currently frequently investigated BFR training does not show higher effects on muscle growth of the lower extremities than conventional low-intensity resistance training.
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We examined the effects of resistance training (RT) frequency performed 3 times per week (RT3) versus RT performed 6 times per week (RT6) under volume-equated conditions in resistance-trained men. Twenty-seven men were randomly allocated to RT3 (n = 14) or RT6 (n = 13). The supervised training intervention lasted for 6-weeks. Upper and lower-body strength were assessed using the one-repetition maximum (1RM) test. Also, muscular endurance (60% 1RM performed to momentary failure), and muscle thickness (elbow flexors, elbow extensors, rectus femoris, and vastus intermedius) were measured pre and post-intervention. Pre-to-post intervention, both groups increased upper-body strength (RT3: +4%; RT6: +6%) and lower-body strength (RT3: +22%; RT6: +18%) with no significant between-group differences. No significant pre-to-post intervention increases in muscular endurance were seen in either of the training groups. Both groups increased elbow extensor thickness (RT3: +14%; RT6: +11%), rectus femoris thickness (RT3: +5%; RT6: +6%), and vastus intermedius thickness (RT3: +10%; RT6: +11%) with no significant between-group differences. Only the RT3 group significantly increased elbow flexor thickness from pre-to-post intervention (+7%). When training volume is equated, it seems that RT performed either 3 or 6 times per week can result in similar strength gains over a 6-week training period. Furthermore, under volume-equated conditions, comparable hypertrophy results may also be expected with both RT frequencies. Finally, no changes were seen in muscular endurance possibly because of the considerable inter-individual variability in the responses. The findings presented herein might be of interest to coaches, exercise practitioners, athletes, and recreational trainees.
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Background: This study investigated the effect of volume-matched strength training programs with different frequency and subsequent detraining on muscle size and strength. Methods: During a training period of 11 weeks, untrained subjects (age: 22.3 ± 0.9 years, height: 173.1 ± 4.8 cm and body mass: 66.8 ± 8.4 kg) performed knee-extension exercise at 67% of their estimated one-repetition maximum either one session per week (T1 group: 6 sets of 12 repetitions per session; n = 10) or three sessions per week (T3 group: 2 sets of 12 repetitions per session; n = 10). Rating of perceived exertion (RPE) and muscle stiffness were measured as an index of muscle fatigue and muscle damage, respectively. The magnitude of muscle hypertrophy was assessed with thigh circumference and the quadriceps muscle thickness. The changes in muscle strength were measured with isometric maximum voluntary contraction torque (MVC). Results: During the training period, RPE was significantly higher in the T1 than in the T3 (p < 0.001). After 11 weeks of training, both groups exhibited significant improvements in thigh circumference, muscle thickness, and MVC compared with baseline values. However, there was a significant group difference in MVC improvement at week 11 (T1: 43.5 ± 15.5%, T3: 65.2 ± 23.2%, p < 0.05). After 6 weeks of detraining, both groups showed the significant decreases in thigh circumference and muscle thickness from those at the end of training period, while no significant effect of detraining was observed in MVC. Conclusion: These results suggest that three training sessions per week with two sets are recommended for untrained subjects to improve muscle strength while minimizing fatigue compared to one session per week with six sets.
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Zaroni, RS, Brigatto, FA, Schoenfeld, BJ, Braz, TV, Benvenutti, JC, Germano, MD, Marchetti, PH, Aoki, MS, and Lopes, CR. High resistance-training frequency enhances muscle thickness in resistance-trained men. J Strength Cond Res 33(7S): S140-S151, 2019-The purpose of this study was to compare the effect a split training routine with muscle groups trained once per week (SPLIT) vs. whole-body split training routine with muscle groups trained 5 days per week (TOTAL) on neuromuscular adaptations in well-trained men. Eighteen healthy men (height = 177.8 ± 6.6 cm; total body mass = 84.4 ± 8.1 kg; age = 26.4 ± 4.6 years) were recruited to participate in this study. The experimental groups were matched according to baseline strength and then randomly assigned to 1 of the 2 experimental groups: SPLIT (n = 9) or TOTAL (n = 9). Prestudy and poststudy testing included 1RM for bench press, parallel back-squat and machine close-grip seated row, as well as an ultrasound analysis of the muscle thickness (MT) of the elbow flexors, triceps brachii, and vastus lateralis. After 8 weeks of training, no significant difference between groups was noted for all 1RM tests (p > 0.05). TOTAL induced a significantly greater increase in MT of the forearm flexors and vastus lateralis (p < 0.05). In conclusion, muscle strength increment is similar regardless of the experimental conditions studied; however, TOTAL may confer a potentially superior hypertrophic effect.
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Background The objective of the present study was to compare the effects of equal-volume resistance training (RT) performed with different training frequencies on muscle size and strength in trained young men. Methods Sixteen men with at least one year of RT experience were divided into two groups, G1 and G2, that trained each muscle group once and twice a week, respectively, for 10 weeks. Elbow flexor muscle thickness (MT) was measured using a B-Mode ultrasound and concentric peak torque of elbow extensors and flexors were assessed by an isokinetic dynamometer. Results ANOVA did not reveal group by time interactions for any variable, indicating no difference between groups for the changes in MT or PT of elbow flexors and extensors. Notwithstanding, MT of elbow flexors increased significantly (3.1%, P < 0.05) only in G1. PT of elbow flexors and extensors did not increase significantly for any group. Discussion The present study suggest that there were no differences in the results promoted by equal-volume resistance training performed once or twice a week on upper body muscle strength in trained men. Only the group performing one session per week significantly increased the MT of their elbow flexors. However, with either once or twice a week training, adaptations appear largely minimal in previously trained males.
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The purpose of this study was to investigate the chronic effects of training muscle groups 1 day per week vs. 2 days per week on neuromuscular performance and morphological adaptations in trained men with the number of sets per muscle group equated between conditions. Participants were randomly assigned in 2 experimental groups: 1 session·wk-1 per muscle group (G1, n = 10), where every muscle group was trained once a week with 16 sets or 2 sessions·wk-1 per muscle group (G2, n = 10), where every muscle group was trained twice a week with 8 sets per session. All other variables were held constant over the 8-week study period. No significant difference between conditions for maximal strength in the back squat or bench press, muscle thickness in the elbow extensors, elbow flexors, or quadriceps femoris, and muscle endurance in the back squat and bench press performed at 60% 1RM was detected. Effect size favored G2 for some outcome measurements, suggesting the potential of a slight benefit to the higher training frequency. In conclusion, both G1 and G2 significantly enhance neuromuscular adaptations, with a similar change noted between experimental conditions. Keywords: Split body routine; resistance training frequency; muscle hypertrophy; maximal strength.
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The main objective of the study was to compare the effect of different weekly frequencies of resistance training (RT) on strength and body composition in untrained individuals who participated in a corporate wellness program after a three-month period. 48 men and 36 women within the ages of 30 to 45 years old were selected and they were divided into four groups that trained either two, three or four times per week, and a control group. Each group followed the same RT program. The participants completed 3 sets of 10-12RM of each exercise, with the exception of the abdominal crunch that followed a 15-20RM rep range per set. The loads were readjusted every time the upper training zone limit was surpassed. The rest interval between sets and exercises was between 60-90 seconds long. All sessions were supervised by a Physical Education professional with experience in resistance training. Anthropometric measurements and 10RM tests were done to analyze dependent variables. All groups presented significant increases in 10RM loads in all exercises (p < 0.05) and no differences were noted between groups (p > 0.05). Muscle mass was not significantly altered in any of the groups (p > 0.05). Body fat percentage was only reduced in the group that trained four times per week (p < 0.05). It was concluded that in a period of up to twelve weeks and for untrained individuals, even small weekly doses of RT can promote positive adaptations in strength and that when it comes to reducing body fat percentage, more frequency may be necessary.
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The main purpose of this study was compare the effects of resistance training (RT) performed two versus three times per week on phase angle (a cellular health indicator) in older women. Thirty-nine women (69.1±5.5 years) were randomly assigned to perform a RT program two (G2X) or three (G3X) days per week for 12 weeks. The RT was a whole-body program (8 exercises, 1 set, 10-15 repetitions). Phase angle, resistance, reactance, and total body water were assessed by bioimpedance spectroscopy. Intracellular water, reactance, and phase angle increased significantly in G2X (2.1%, 3.0%, and 5.6%, respectively) and G3X (5.0%, 6.9%, and 10.3% respectively) from pre- to post-training, with no significant difference between groups. Bioimpedance resistance decreased similarly in both groups (G2X=-1.7% vs. G3X=-3.2%). We conclude that a single set RT program with a frequency of two days per week may be sufficient to promote an improvement in cellular health in older women.
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Purpose: The myriad consequences of age-related muscle atrophy include reduced muscular strength, power, and mobility; increased risk of falls, disability, and metabolic disease; and compromised immune function. At its root, aging muscle atrophy results from a loss of myofibers and atrophy of the remaining type II myofibers. The purpose of this trial (NCT02442479) was to titrate the dose of resistance training (RT) in older adults in an effort to maximize muscle regrowth and gains in muscle function. Methods: A randomized, four-arm efficacy trial in which four, distinct exercise prescriptions varying in intensity, frequency, and contraction mode/rate were evaluated: (Janssen et al., 2004) high-resistance concentric-eccentric training (H) 3d/week (HHH); (Szulc et al., 2010) H training 2d/week (HH); (Lexell et al., 1988) 3d/week mixed model consisting of H training 2d/week separated by 1 bout of low-resistance, high-velocity, concentric only (L) training (HLH); and (Doherty, 2003) 2d/week mixed model consisting of H training 1d/week and L training 1d/week (HL). Sixty-four randomized subjects (65.5±3.6y) completed the trial. All participants completed the same 4weeks of pre-training consisting of 3d/week followed by 30weeks of randomized RT. Results: The HLH prescription maximized gains in thigh muscle mass (TMM, primary outcome) and total body lean mass. HLH also showed the greatest gains in knee extension maximum isometric strength, and reduced cardiorespiratory demand during steady-state walking. HHH was the only prescription that led to increased muscle expression of pro-inflammatory cytokine receptors and this was associated with a lesser gain in TMM and total body lean mass compared to HLH. The HL prescription induced minimal muscle regrowth and generally lesser gains in muscle performance vs. the other prescriptions. Major conclusions: The HLH prescription offers distinct advantages over the other doses, while the HL program is subpar. Although limited by a relatively small sample size, we conclude from this randomized dose-response trial that older adults benefit greatly from 2d/week high-intensity RT, and may further benefit from inserting an additional weekly bout of low-load, explosive RT. Trial registration: ClinicalTrials.govNCT02442479.
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This study investigated the effects of different reduced strength training (RST) frequencies on half-squat 1 RM and quadriceps cross-sectional area (QCSA). Thirty-three untrained males (24.7±3.9 years; 1.73±0.08m; 74.6±8.4kg) underwent a 16-week experimental period (i.e. eight weeks of strength training [ST] followed by additional eight weeks of RST). During the ST period, the participants performed 3–4 sets of 6–12 RM, three sessions/week in half-squat and knee extension exercises. Following ST, the participants were randomly allocated to one of three groups: reduced strength training with one (RST1) or two sessions per week (RST2), and ceased training (CT). Both RST1 and RST2 groups had their training frequency and total training volume-load (i.e. RST1 = 50.3% and RST2 = 57.1%) reduced, while the CT group stopped training completely. Half-squat 1 RM (RST1=27.9%; RST2=26.7%; and CT=28.4%) and QCSA (RST1 = 6.1%; RST2 = 6.9%; and CT = 5.8%) increased significantly (p < .05) in all groups after eight weeks of ST. No significant changes were observed in 1 RM and QCSA for RST1 and RST2 groups after the RST period, while the CT group demonstrated a decrease in half-squat 1 RM (22.6%) and QCSA (5.4%) when compared to the ST period (p < .05). In conclusion, different RST frequencies applied were able to maintain muscle mass and strength performance obtained over the regular ST period. Thus, it appears that RST frequency does not affect the maintenance of muscle mass and strength in untrained males, as long as volume-load is equated between frequencies. THIS MANUSCRIPT IS PROTECTED BY COPYRIGHT.
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The principle of progressive overload must be adhered to for individuals to continually increase muscle size with resistance training. While the majority of trained individuals adhere to this principle by increasing the number of sets performed per exercise session, this does not appear to be an effective method for increasing muscle size once a given threshold is surpassed. Opposite the numerous studies examining differences in training loads and sets of exercise performed, a few studies have assessed the importance of training frequency with respect to muscle growth, none of which have tested very high frequencies of training (e.g., 7 days a week). The lack of studies examining such frequencies may be related to the American College of Sports Medicine recommendation that trained individuals use split routines allowing at least 48 h of rest between exercises that stress the same muscle groups. Given the attenuated muscle protein synthetic response to resistance exercise present in trained individuals, it can be hypothesized that increasing the training frequency would allow for more frequent elevations in muscle protein synthesis and more time spent in a positive net protein balance. We hypothesize that increasing the training frequency, as opposed to the training load or sets performed, may be a more appropriate strategy for trained individuals to progress a resistance exercise program aimed at increasing muscle size.
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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.
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Background A number of resistance training (RT) program variables can be manipulated to maximize muscular hypertrophy. One variable of primary interest in this regard is RT frequency. Frequency can refer to the number of resistance training sessions performed in a given period of time, as well as to the number of times a specific muscle group is trained over a given period of time. Objective We conducted a systematic review and meta-analysis to determine the effects of resistance training frequency on hypertrophic outcomes. Methods Studies were deemed eligible for inclusion if they met the following criteria: (1) were an experimental trial published in an English-language refereed journal; (2) directly compared different weekly resistance training frequencies in traditional dynamic exercise using coupled concentric and eccentric actions; (3) measured morphologic changes via biopsy, imaging, circumference, and/or densitometry; (4) had a minimum duration of 4 weeks; and (5) used human participants without chronic disease or injury. A total of ten studies were identified that investigated RT frequency in accordance with the criteria outlined. Results Analysis using binary frequency as a predictor variable revealed a significant impact of training frequency on hypertrophy effect size (P = 0.002), with higher frequency being associated with a greater effect size than lower frequency (0.49 ± 0.08 vs. 0.30 ± 0.07, respectively). Statistical analyses of studies investigating training session frequency when groups are matched for frequency of training per muscle group could not be carried out and reliable estimates could not be generated due to inadequate sample size. Conclusions When comparing studies that investigated training muscle groups between 1 to 3 days per week on a volume-equated basis, the current body of evidence indicates that frequencies of training twice a week promote superior hypertrophic outcomes to once a week. It can therefore be inferred that the major muscle groups should be trained at least twice a week to maximize muscle growth; whether training a muscle group three times per week is superior to a twice-per-week protocol remains to be determined.
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Systematic reviews and meta-analyses have become increasingly important in health care. Clinicians read them to keep up to date with their field [1],[2], and they are often used as a starting point for developing clinical practice guidelines. Granting agencies may require a systematic review to ensure there is justification for further research [3], and some health care journals are moving in this direction [4]. As with all research, the value of a systematic review depends on what was done, what was found, and the clarity of reporting. As with other publications, the reporting quality of systematic reviews varies, limiting readers' ability to assess the strengths and weaknesses of those reviews. Several early studies evaluated the quality of review reports. In 1987, Mulrow examined 50 review articles published in four leading medical journals in 1985 and 1986 and found that none met all eight explicit scientific criteria, such as a quality assessment of included studies [5]. In 1987, Sacks and colleagues [6] evaluated the adequacy of reporting of 83 meta-analyses on 23 characteristics in six domains. Reporting was generally poor; between one and 14 characteristics were adequately reported (mean = 7.7; standard deviation = 2.7). A 1996 update of this study found little improvement [7]. In 1996, to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement (QUality Of Reporting Of Meta-analyses), which focused on the reporting of meta-analyses of randomized controlled trials [8]. In this article, we summarize a revision of these guidelines, renamed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), which have been updated to address several conceptual and practical advances in the science of systematic reviews (Box 1). Box 1: Conceptual Issues in the Evolution from QUOROM to PRISMA Completing a Systematic Review Is an Iterative Process The conduct of a systematic review depends heavily on the scope and quality of included studies: thus systematic reviewers may need to modify their original review protocol during its conduct. Any systematic review reporting guideline should recommend that such changes can be reported and explained without suggesting that they are inappropriate. The PRISMA Statement (Items 5, 11, 16, and 23) acknowledges this iterative process. Aside from Cochrane reviews, all of which should have a protocol, only about 10% of systematic reviewers report working from a protocol [22]. Without a protocol that is publicly accessible, it is difficult to judge between appropriate and inappropriate modifications.
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The purpose of this study was to investigate the effects of training muscle groups 1 day per week using a split-body routine versus 3 days per week using a total-body routine on muscular adaptations in well-trained men. Subjects were 20 male volunteers (height = 1.76 ± 0.05 m; body mass = 78.0 ± 10.7 kg; age = 23.5 ± 2.9 years) recruited from a university population. Participants were pair-matched according to baseline strength and then randomly assigned to 1 of 2 experimental groups: a split-body routine (SPLIT) where multiple exercises were performed for a specific muscle group in a session with 2-3 muscle groups trained per session (n = 10), or; a total-body routine (TOTAL), where 1 exercise was performed per muscle group in a session with all muscle groups trained in each session (n = 10). Subjects were tested pre- and post-study for 1 repetition maximum strength in the bench press and squat, and muscle thickness of forearm flexors, forearm extensors, and vastus lateralis. Results showed significantly greater increases in forearm flexor muscle thickness for TOTAL compared to SPLIT. No significant differences were noted in maximal strength measures. The findings suggest a potentially superior hypertrophic benefit to higher weekly resistance training frequencies.
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Muscle protein synthesis (MPS) is stimulated by resistance exercise (RE) and is further stimulated by protein ingestion. The summation of periods of RE-induced increases in MPS can induce hypertrophy chronically. As such, studying the response of MPS with resistance training (RT) is informative, as adaptations in this process can modulate muscle mass gain. Previous studies have shown that the amplitude and duration of increases in MPS after an acute bout of RE are modulated by an individual's training status. Nevertheless, it has been shown that the initial responses of MPS to RE and nutrition are not correlated with subsequent hypertrophy. Thus, early acute responses of MPS in the hours after RE, in an untrained state, do not capture how MPS can affect RE-induced muscle hypertrophy. The purpose of this review is provide an in-depth understanding of the dynamic process of muscle hypertrophy throughout RT by examining all of the available data on MPS after RE and in different phases of an RT programme. Analysis of the time course and the overall response of MPS is critical to determine the potential protein accretion after an RE bout. Exercise-induced increases in MPS are shorter lived and peak earlier in the trained state than in the untrained state, resulting in a smaller overall muscle protein synthetic response in the trained state. Thus, RT induces a dampening of the MPS response, potentially limiting protein accretion, but when this occurs remains unknown.
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The main purpose of the investigation reported here was to analyze the effect of resistance training (RT) performed at different weekly frequencies on flexibility in older women. Fifty-three older women (≥60 years old) were randomly assigned to perform RT either two (n=28; group "G2x"), or three (n=25; group "G3x") times per week. The RT program comprised eight exercises in which the participants performed one set of 10-15 repetitions maximum for a period of 12 weeks. Anthropometric, body-composition, and flexibility measurements were made at baseline and post-study. The flexibility measurements were obtained by a fleximeter. A significant group-by-time interaction (P<0.01) was observed for frontal hip flexion, in which G3x showed a higher increase than G2x (+12.8% and +3.0%, respectively). Both groups increased flexibility in cervical extension (G2x=+19.1%, G3x=+20.0%), right hip flexion (G2x=+14.6%, G3x=+15.9%), and left hip flexion (G2x=+25.7%, G3x=+19.2%), with no statistical difference between groups. No statistically significant differences were noted for the increase in skeletal muscle mass between training three versus two times a week (+7.4% vs +4.4%, respectively). Twelve weeks of RT improves the flexibility of different joint movements i