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Effect Of Resistance Training To Muscle Failure Versus Volitional Interruption At High- And Low-Intensities On Muscle Mass And Strength
Abstract
The purpose of the present study was to investigate the effects of resistance training (RT) at high- and low-intensities performed to muscle failure or volitional interruption on muscle strength, cross-sectional area (CSA), pennation angle (PA) and muscle activation. Thirty-two untrained men participated in the study. Each leg was allocated in one of four unilateral RT protocols: RT to failure at high (HIRT-F) and low (LIRT-F) intensities, and RT to volitional interruption (repetitions performed to the point in which participants voluntarily interrupted the exercise) at high (HIRT-V) and low (LIRT-V) intensities. Muscle strength (1-RM), CSA, PA and muscle activation by amplitude of the electromyography (EMG) signal were assessed before (Pre), after 6 (6W) and 12 (12W) weeks. 1-RM increased similarly after 6W (range: 15.8 - 18.9%, ES: 0.41- 0.58) and 12W (range: 25.6 - 33.6%, ES: 0.64 - 0.98) for all protocols. All protocols were similarly effective in increasing CSA after 6W (range: 3.0 - 4.6%, ES: 0.10 - 0.24) and 12W (range: 6.1 - 7.5%, ES: 0.22 - 0.26). PA increased after 6W (~3.5) and 12W (~9%; main time effect, P < 0.0001), with no differences between protocols. EMG values were significantly higher for the high-intensity protocols at all times (main intensity effect, P < 0.0001). In conclusion, both high- and low-intensity RT performed to volitional interruption are equally effective in increasing muscle mass, strength and PA when compared to RT performed to muscle failure.
... (1) Theme A: Studies comparing a group(s) performing RT to momentary muscular failure to a non-failure group(s) (Amdi et al., 2021;Fonseca et al., 2020;Gantois et al., 2021;Kassiano et al., 2021;Lacerda et al., 2020;Lasevicius et al., 2019;Mangine et al., 2022;S Martorelli et al., 2017;Nobrega et al., 2018;Santanielo et al., 2020;Santos et al., 2019). (2) Theme B: Studies comparing a group(s) performing RT to set failure (defined as anything other than the definition of momentary muscular failure) to a non-failure group(s) (Bergamasco et al., 2020;Costa et al., 2021;Garcia-Ramos et al., 2020;Gonzalez-Badillo et al., 2016;Gonzalez-Hernandez et al., 2021;Gorostiaga et al., 2012Gorostiaga et al., , 2014Karsten et al., 2021;Linnamo et al., 2005;AS Martorelli et al., 2021;Moran-Navarro et al., 2017;Pareja-Blanco, Rodriguez-Rosell, et al., 2020; Pareja-Blanco, Rodriguez-Rosell, Sanchez-Medina, Ribas-Serna, et al., 2017; Raastad et al., 2000;Sampson & Groeller, 2016;Sanchez-Medina & Gonzalez-Badillo, 2011;Shibata et al., 2019;Terada et al., 2021;Vasquez et al., 2013). ...
... This approach prevents insight into how differences in RT proximity-to-failure between conditions may affect study findings. To illustrate how set termination prescriptions in non-failure RT can influence study findings, Nobrega et al. (Nobrega et al., 2018) and Lasevicius et al. (Lasevicius et al., 2019) both assessed muscle hypertrophy outcomes following RT performed to momentary muscular failure versus non-failure. Participants in the non-failure condition of the Nobrega et al. (Nobrega et al., 2018) study "voluntarily interrupted the exercise before muscle failure", while those in Lasevicius et al. (Lasevicius et al., 2019) performed a predetermined number of repetitions in each set (60% of total repetitions perform in the set failure condition). ...
... To illustrate how set termination prescriptions in non-failure RT can influence study findings, Nobrega et al. (Nobrega et al., 2018) and Lasevicius et al. (Lasevicius et al., 2019) both assessed muscle hypertrophy outcomes following RT performed to momentary muscular failure versus non-failure. Participants in the non-failure condition of the Nobrega et al. (Nobrega et al., 2018) study "voluntarily interrupted the exercise before muscle failure", while those in Lasevicius et al. (Lasevicius et al., 2019) performed a predetermined number of repetitions in each set (60% of total repetitions perform in the set failure condition). As a result, the proximity-to-failure reached in the non-failure condition in Nobrega et al. (Nobrega et al., 2018) was likely closer to momentary muscular failure compared to Lasevicius et al. (Lasevicius et al., 2019), which may influence conclusions regarding the relative efficacy of RT to momentary muscular ) compared a set failure condition performing "3 sets of 8 repetitions to failure", indicated as "3 × 8 (8)", with a non-failure condition performing "only half the maximum number of repetitions" possible, indicated as "3 × 4 (8)" and implying that participants would only be capable of performing four additional repetitions before reaching momentary muscular failure. ...
While proximity-to-failure is considered an important resistance training (RT) prescription variable, its influence on physiological adaptations and short-term responses to RT is uncertain. Given the ambiguity in the literature, a scoping review was undertaken to summarise evidence for the influence of proximity-to-failure on muscle hypertrophy, neuromuscular fatigue, muscle damage and perceived discomfort. Literature searching was performed according to PRISMA-ScR guidelines and identified three themes of studies comparing either: i) RT performed to momentary muscular failure versus non-failure, ii) RT performed to set failure (defined as anything other than momentary muscular failure) versus non-failure, and iii) RT performed to different velocity loss thresholds. The findings highlight that no consensus definition for "failure" exists in the literature, and the proximity-to-failure achieved in "non-failure" conditions is often ambiguous and variable across studies. This poses challenges when deriving practical recommendations for manipulating proximity-to-failure in RT to achieve desired outcomes. Based on the limited available evidence, RT to set failure is likely not superior to non-failure RT for inducing muscle hypertrophy, but may exacerbate neuromuscular fatigue, muscle damage, and post-set perceived discomfort versus non-failure RT. Together, these factors may impair post-exercise recovery and subsequent performance, and may also negatively influence long-term adherence to RT.
KEY POINTS (1) This scoping review identified three broad themes of studies investigating proximity-to-failure in RT, based on the specific definition of set failure used (and therefore the research question being examined), to improve the validity of study comparisons and interpretations. (2) There is no consensus definition for set failure in RT, and the proximity-to-failure achieved during non-failure RT is often unclear and varies both within and between studies, which together poses challenges when interpreting study findings and deriving practical recommendations regarding the influence of RT proximity-to-failure on muscle hypertrophy and other short-term responses. (3) Based on the limited available evidence, performing RT to set failure is likely not superior to non-failure RT to maximise muscle hypertrophy, but the optimal proximity to failure in RT for muscle hypertrophy is unclear and may be moderated by other RT variables (e.g., load, volume-load). Also, RT performed to set failure likely induces greater neuromuscular fatigue, muscle damage, and perceived discomfort than non-failure RT, which may negatively influence RT performance, post-RT recovery, and long-term adherence.
... Similar findings to studies measuring muscle thickness were noted in the 13 studies that measured whole-muscle CSA via magnetic resonance imaging (MRI) (Fink et al., 2016;Hisaeda et al., 1996;Holm et al., 2008;Lasevicius et al., 2019;Mitchell et al., 2012;Ogasawara et al., 2013;Popov et al., 2006;Tanimoto & Ishii, 2006;Wallerstein et al., 2012), computerized tomography (CT) scan (Kalapotharakos et al., 2004;Moss et al., 1997;, or ultrasound (Nobrega et al., 2018). This is perhaps not surprising, as muscle thickness (measured by ultrasound) correlates well with muscle CSA as measured by CT or MRI (Franchi et al., 2018). ...
... This is perhaps not surprising, as muscle thickness (measured by ultrasound) correlates well with muscle CSA as measured by CT or MRI (Franchi et al., 2018). Of the 13 studies, nine (Fink et al., 2016;Hisaeda et al., 1996;Lasevicius et al., 2019;Mitchell et al., 2012;Nobrega et al., 2018;Ogasawara et al., 2013;Popov et al., 2006;Wallerstein et al., 2012) identified a similar increase in whole-muscle CSA between high-load and low-load RT groups, three (Holm et al., 2008;Kalapotharakos et al., 2004;Tanimoto & Ishii, 2006) demonstrated an advantage to high-load RT, and only one (Moss et al., 1997) found greater improvements in the low-load condition. ...
... ;Au et al., 2017;Campos et al., 2002;Fatouros et al., 2006;Holm et al., 2008;Jenkins et al., 2017;Jessee et al., 2018;Jones et al., 2001;Kalapotharakos et al., 2004;Lasevicius et al., 2019Lasevicius et al., , 2018Mitchell et al., 2012;Moss et al., 1997;Ogasawara et al., 2013;Rana et al., 2008;Richardson et al., 2019;Schoenfeld et al., 2015;Seynnes et al., 2004;De Vos et al., 2005) out of the 36 studies found greater improvements in 1-RM strength with high-load compared to low-load RT, while equivalent improvements between both loading conditions were noted in 15 studies(Franco et al., 2019;Harris et al., 2004;Hortobágyi et al., 2001;Ikezoe et al., 2020;Kerr et al., 1996;Morton et al., 2016;Nobrega et al., 2018;Ribeiro et al., 2020;Stefanaki et al., 2019;Stone & Coulter, 1994;Taaffe et al., 1996;Tanimoto & Ishii, 2006;Tanimoto et al., 2008;Wallerstein et al., 2012). One study(Bezerra et al., 2019) measured dynamic 5-RM strength (for the seated row exercise) and found equivalent improvements between high-load and low-load RT.Meta-analytic outcomes for dynamic 1-RM strength are shown in ...
This systematic review and meta-analysis determined resistance training (RT) load effects on various muscle hypertrophy, strength, and neuromuscular performance task [e.g., countermovement jump (CMJ)] outcomes. Relevent studies comparing higher-load [>60% 1-repetition maximum (RM) or <15-RM] and lower-load (≤60% 1-RM or ≥ 15-RM) RT were identified, with 45 studies (from 4713 total) included in the meta-analysis. Higher- and lower-load RT induced similar muscle hypertrophy at the whole-body (lean/fat-free mass; [ES (95% CI) = 0.05 (−0.20 to 0.29), P = 0.70]), whole-muscle [ES = 0.06 (−0.11 to 0.24), P = 0.47], and muscle fibre [ES = 0.29 (−0.09 to 0.66), P = 0.13] levels. Higher-load RT further improved 1-RM [ES = 0.34 (0.15 to 0.52), P = 0.0003] and isometric [ES = 0.41 (0.07 to 0.76), P = 0.02] strength. The superiority of higher-load RT on 1-RM strength was greater in younger [ES = 0.34 (0.12 to 0.55), P = 0.002] versus older [ES = 0.20 (−0.00 to 0.41), P = 0.05] participants. Higher- and lower-load RT therefore induce similar muscle hypertrophy (at multiple physiological levels), while higher-load RT elicits superior 1-RM and isometric strength. The influence of RT loads on neuromuscular task performance is however unclear.
... In addition, it has been previously suggested that MF training would induce a greater fatigue of the active motor units requiring additional higher threshold motor units to be recruited for the maintenance of force production to complete a given task (37,43). However, Nóbrega et al. (34) verified similar neuromuscular activation between protocols performed to MF and volitional interruption (repetitions performed to the point when subjects voluntarily stop the exercise) with same intensity did not indicate the occurrence of a greater recruitment of motor units during MF training. Furthermore, given that MF and volitional interruption are 2 different criteria characterizing protocols performed with maximum repetition numbers, data from that study does not allow a better understanding about the effect of MF and not to muscle failure (NMF) protocols. ...
... However, data from a recent meta-analysis published by Davies et al. (10) investigating MF vs. NMF training effects on maximal strength response, demonstrated that both training strategies provided similar muscle strength gains. Among the previous studies that showed contradictory results (MF vs. NMF), some reported superiority for MF (15,37), others reported support for NMF training (21), and some reported similar outcomes (9,22,29,34,36). These differences in observed results between studies could be partially due to interindividual differences in responsiveness to different training protocols (8). ...
... These differences in observed results between studies could be partially due to interindividual differences in responsiveness to different training protocols (8). In fact, large muscular strength and hypertrophy even when subjects perform standardized training protocols, and hence, studies with intraindividual experimental designs have been performed to minimize this problem (34). However, to the best of our knowledge, no study with an intraindividual design has evaluated the chronic effects of both training strategies (MF and NMF) using individual analyses. ...
The aim of this study was to investigate the effects of muscle failure (MF) or non-MF (NMF) training on strength and muscle hypertrophy relative gains (average and individual data). Ten men untrained in resistance training participated in the study. Each leg was allocated in 1 of 2 unilateral training protocols (MF or NMF with equal volume) on knee extension exercise. Both protocols were performed with 3–4 sets, 3 minutes’ rest, and 55–60% of one repetition maximum (1RM). Rectus femoris and vastus lateralis muscles cross-sectional area (CSA), maximal muscle strength (1RM and maximal voluntary isometric contraction), and muscular endurance (maximum number of repetition) were assessed before and after 14 weeks. In addition, neuromuscular activation by normalized root mean square of the electromyographic signal (EMGRMS) was measured in 2nd and 35th training sessions. The average results showed that both training protocols were similarly effective in inducing increases in strength and muscle hypertrophy gains. However, individual analysis data suggest that NMF protocol with equal volume may promote similar or even greater muscle hypertrophy (vastus lateralis) and muscular endurance performance when compared with MF protocol. Also, normalized EMGRMS responses analyzed during 2nd and 35th sessions were similar in MF and NMF protocols for rectus femoris and vastus lateralis muscles. In conclusion, MF and NMF protocol conducted with the same total repetition numbers produced similar maximal muscle strength performance and neuromuscular activation. Nevertheless, NMF training could be a more appropriate strategy to increase muscle hypertrophy (vastus lateralis) and muscular endurance performance in untrained individuals when compared with MF.
... However, there is evidence that a high level of muscle activity can be achieved by HL-RT before reaching muscle failure (34), thereby calling into question the need to train to failure. Findings from longitudinal studies on the topic are conflicting with some studies showing advantages for achieving muscle failure (7,29,33) while others reporting no benefit (21,25,31). A confounding issue in these studies is that advantages for muscle failure with HL-RT occurred concomitantly with a greater total training volume, suggesting that positive results may have been induced by a higher total training volume rather than muscle failure. ...
... Accordingly, it has been hypothesized that the fatigue associated with training to muscle failure results in the progressive recruitment of a greater number of high-threshold motor units, which conceivably could enhance muscle hypertrophy (29,38). However, when performing repetitions in proximity to failure, but not going to failure, muscle activity seems to be the same as when repetitions are taken to failure (25,34). To date, only one study has investigated the effect of muscle failure in LL-RT and HL-RT. ...
... To date, only one study has investigated the effect of muscle failure in LL-RT and HL-RT. Nóbrega et al. (25) randomized untrained men to perform resistance training using either muscle failure or volitional interruption at low and high loads (e.g., 30 and 80% 1RM, respectively). After 12 weeks, similar increases in muscle thickness were observed both with and without muscle failure independent of the load used. ...
Lasevicius, T, Schoenfeld,BJ, Silva-Batista, C,Barros, TdS,Aihara, AY,Brendon,H, Longo,AR, Tricoli, V, Peres,BdA, and Teixeira,EL.
Muscle failure promotes greater muscle hypertrophy in low-load but not in high-load resistance training. J Strength Cond Res XX(X):
000–000, 2019—The purpose of this study was to investigate the effects of an 8-week resistance training program at low and high loads
performed with and without achieving muscle failure on muscle strength and hypertrophy. Twenty-five untrained men participated in the
8-week study. Each lower limb was allocated to 1 of 4 unilateral knee extension protocols: repetitions to failure with low load (LL-RF;
;34.4 repetitions); repetitions to failure with high load (HL-RF;;12.4 repetitions); repetitions not to failure with low load (LL-RNF;;19.6
repetitions); and repetitions not to failure with high load (HL-RNF; ;6.7 repetitions). All conditions performed 3 sets with total training
volume equated between conditions. The HL-RF and HL-RNF protocols used a load corresponding to 80% 1 repetitionmaximum (RM),
while LL-RF and LL-RNF trained at 30%1RM.Muscle strength (1RM) and quadriceps cross-sectional area (CSA) were assessed before
and after intervention. Results showed that 1RMchanges were significantly higher for HL-RF (33.8%, effect size [ES]: 1.24) and HL-RNF
(33.4%, ES: 1.25) in the post-test when compared with the LL-RF and LL-RNF protocols (17.7%, ES: 0.82 and 15.8%, ES: 0.89,
respectively). Quadriceps CSA increased significantly for HL-RF (8.1%, ES: 0.57), HL-RNF (7.7%, ES: 0.60), and LL-RF (7.8%, ES: 0.45),
whereas no significant changes were observed in the LL-RNF (2.8%, ES: 0.15).We conclude that when training with low loads, training
with a high level of effort seems to have greater importance than total training volume in the accretion of muscle mass, whereas for high
load training, muscle failure does not promote any additional benefits. Consistent with previous research, muscle strength gains are
superior when using heavier loads.
Key Words: muscular failure, muscle mass, strength, low load and high load
... Concerning RD, the ACSM (2009) recommends a moderate duration (e.g., 2 s for concentric action and 2 s for eccentric action (2 s: 2 s)) for untrained. However, several studies have neglected RD control by not reporting or simply not monitoring this variable (Angleri, Ugrinowitsch & Libardi, 2017;Barcelos et al., 2018;De Salles et al., 2016;Lasevicius et al., 2018;Nobrega et al., 2018b;Radaelli et al., 2015). In this sense, it is unknown whether the lack of control of this variable (i.e., RD self-selected) would have any impact on RT adaptations. ...
... However, muscle fiber activation and subsequent anabolic signaling are independent of EMG amplitude when resistance exercise is performed to concentric muscle failure (Morton et al., 2019). Additionally, similar muscle strength gains and hypertrophy between RT protocols with different EMG amplitudes has been recently shown (Mitchell et al., 2012;Morton et al., 2016;Nobrega et al., 2018b;Schoenfeld et al., 2014). Thus, although suggestive, a higher EMG amplitude is not necessarily an advantage for a SELF protocol. ...
... Full-size DOI: 10.7717/peerj.8697/ fig-2 in the current study, others studies have also shown similar increases in strength gains and muscle hypertrophy despite differences in VL (Barcelos et al., 2018;Bottaro et al., 2011;Mitchell et al., 2012;Nobrega et al., 2018b;Ostrowski et al., 1997). Thus, our findings suggest that there may be a "ceiling effect" to the dose-response relationship between RT volume and increases in muscle strength and hypertrophy. ...
The aim of this study was to compare the effect of self-selected repetition duration (SELF), with and without volume load (VL) equalized with controlled repetition duration (CON) on muscle strength and hypertrophy in untrained males. We used a within-subjects design in which 20 volunteers (age: 24.7 ± 2.9 years) had one leg randomly assigned to CON (i.e., 2 s concentric, 2 s eccentric) and the other to SELF or to self-selected repetition duration with equalized volume load (SELF-EV). One repetition maximum (1-RM) and muscle cross-sectional area (CSA) were measured at baseline (Pre) and after (Post) resistance training (RT; 2×/wk for 8 weeks). For the main study variables (1-RM and muscle CSA), a mixed-model analysis was performed, assuming repetition duration (SELF, SELF-EV and CON), and time (Pre and Post) as fixed factors and the subjects as random factor for each dependent variable (1-RM and CSA). All RT protocols showed significant increases in values of 1-RM from Pre (CON: 73.7 ± 17.6 kg; SELF: 75.9 ± 17.7 kg; and SELF-EV: 72.6 ± 16.9 kg) to Post (CON: 83.4 ± 19.9 kg, effect size (ES): 0.47; SELF: 84 ± 19.1 kg, ES: 0.43; and SELF-EV: 83.2 ± 19.9 kg, ES: 0.57, P < 0.0001). Muscle CSA values increased for all protocols from Pre (CON: 12.09 ± 3.14 cm ² ; SELF: 11.91 ± 3.71 cm ² ; and SELF-EV: 11.93 ± 2.32 cm ² ) to Post (CON: 13.03 ± 3.25 cm ² , ES: 0.29; SELF: 13.2 ± 4.16 cm ² , ES: 0.32; and SELF-EV: 13.2 ± 2.35 cm ² , ES: 0.53, P < 0.0001). No significant differences between protocols were found for both 1-RM and CSA ( P > 0.05). Performing RT with SELF, regardless of VL, was equally effective in inducing increases in muscle strength and hypertrophy compared to CON in untrained men.
... Resistance training (RT) is a potent intervention strategy to increase muscle cross-sectional area (i.e., muscle hypertrophy), muscle strength [1] and muscle architecture parameters (e.g., muscle fibre pennation angle and fascicle length) [2][3][4]. To maximize these neuromuscular adaptations, it has been recommended to perform RT until muscle failure (RT-F), defined as the point where the activated muscles are incapable of completing another repetition in the appropriate range of motion [5,6]. ...
... For the RT-NF protocol, participants were previously instructed on and familiarized with the criteria for muscular failure. Thus they were instructed to interrupt repetitions voluntarily, according to each's own perception of fatigue, before reaching that known point of muscular failure, independently of how many repetitions short of failure they stopped at [4,28]. Repetitions were performed at 75% 1-RM. ...
... -1.64 reps), indicating that the non-failure protocol performed sets close to full fatigue. In view of the relationship between fatigue and muscle activation [33], when the exercise is performed close to muscle failure, the level of fatigue seems sufficient for complete muscle activation, as shown in the present study and in others with untrained individuals or who have undergone other training modes [4,16]. Thus, it seems that as long as RT is carried to a point of significant fatigue (likely only 1 to 2 repetitions shy of failure), increases in muscle activation and mass will be similar to those of RT performed to failure. ...
The aim of this study was to compare the effects of resistance training to muscle failure (RT-F) and non-failure (RT-NF) on muscle mass, strength and activation of trained individuals. We also compared the effects of these protocols on muscle architecture parameters. A within-subjects design was used in which 14 participants had one leg randomly assigned to RT-F and the other to RT-NF. Each leg was trained 2 days per week for 10 weeks. Vastus lateralis (VL) muscle cross-sectional area (CSA), pennation angle (PA), fascicle length (FL) and 1-repetition maximum (1-RM) were assessed at baseline (Pre) and after 20 sessions (Post). The electromyographic signal (EMG) was assessed after the training period. RT-F and RT-NF protocols showed significant and similar increases in CSA (RT-F: 13.5% and RT-NF: 18.1%; P < 0.0001), PA (RT-F: 13.7% and RT-NF: 14.4%; P < 0.0001) and FL (RT-F: 11.8% and RT-NF: 8.6%; P < 0.0001). All protocols showed significant and similar increases in leg press (RT-F: 22.3% and RT-NF: 26.7%; P < 0.0001) and leg extension (RT-F: 33.3%, P < 0.0001 and RT-NF: 33.7%; P < 0.0001) 1-RM loads. No significant differences in EMG amplitude were detected between protocols (P > 0.05). In conclusion, RT-F and RT-NF are similarly effective in promoting increases in muscle mass, PA, FL, strength and activation.
... 3,4 Given the hypothesis that training to muscle failure is important for catalyzing resistance training-induced adaptations, several studies examined the effects that this type of training has on muscular strength and hypertrophy, as compared to the effects of training that does not include reaching muscle failure. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, detailed scrutiny of these studies highlights inconsistent findings. For example, some report that training to muscle failure results in greater increases in muscular strength and/or hypertrophy. ...
... training either to or not to muscle failure) can produce similar improvements with respect to these outcomes. 9,16 Some studies even indicate that training to failure has a detrimental effect. 5,6 The inconsistent evidence on this topic currently hinders the ability to draw practical recommendations for training program design. ...
... Since publication of the meta-analysis by Davies et al. 22,23 , 8 additional studies have been published that examine the topic. 8,11,[13][14][15][16][17]21 Thus, an updated meta-analysis would theoretically have a ~2-fold increase in the number of included studies. Furthermore, while the effects of training to or not to muscle failure on muscular strength have been explored via meta-analysis, the same is not true for hypertrophy. ...
Objective
We aimed to perform a systematic review and meta-analysis of the effects of training to muscle failure or non-failure on muscular strength and hypertrophy.
Methods
Meta-analyses of effect sizes (ESs) explored the effects of training to failure vs. non-failure on strength and hypertrophy. Subgroup meta-analyses explored potential moderating effects of variables such as training status (trained vs. untrained), training volume (volume equated vs. non-equated), body region (upper vs. lower), exercise selection (multi- vs. single-joint exercises (only for strength)), and study design (independent vs. dependent groups).
Results
Fifteen studies were included in the review. All studies included young adults as participants. Meta-analysis indicated no significant difference between the training conditions for muscular strength (ES = –0.09; 95% confidence interval (CI): –0.22 to 0.05) and for hypertrophy (ES = 0.22; 95%CI: –0.11 to 0.55). Subgroup analyses that stratified the studies according to body region, exercise selection, or study design showed no significant differences between training conditions. In studies that did not equate training volume between the groups, the analysis showed significant favouring of non-failure training on strength gains (ES = –0.32; 95%CI: –0.57 to –0.07). In the subgroup analysis for resistance-trained individuals, the analysis showed a significant effect of training to failure for muscle hypertrophy (ES = 0.15; 95%CI: 0.03 to 0.26).
Conclusion
Training to muscle failure does not seem to be required for gains in strength and muscle size. However, training in this manner does not seem to have detrimental effects on these adaptations, either. More studies should be conducted among older adults and highly trained individuals to improve the generalizability of these findings.
... A total of 747 healthy men and women with an average age of 23.4 ± 3.0 yr participated in the included studies. Seventeen studies compared low-versus high-load resistance training (2,5,6,33,34,36,38,39,(42)(43)(44)(45)(46)(49)(50)(51)53), four compared lowversus moderate-load (35,40,47,52), five compared moderateversus high-load (7,32,37,41,48), and two studies compared low-versus moderate-versus high-load (3,4 (3)(4)(5)(6)(7)32,(35)(36)(37)(38)(39)43,44,49,50), followed by 8 studies assessing the upper limbs (4,7,32,34,45,47,48,50) and 5 studies assessing the whole body (e.g., dual-energy x-ray absorptiometry) (33,40,42,46,53), whereas lower-body muscle strength was assessed in 20 studies (3)(4)(5)(6)(7)32,33,35,(38)(39)(40)(41)(42)(43)(44)46,48,(50)(51)(52), followed by 12 studies assessing upper-body muscle strength (2,4,7,33,40,41,43,45,47,48,50,51), all using the 1-RM test. Eighteen studies reported the total volume performed during the intervention (4,5,7,(32)(33)(34)(35)(37)(38)(39)(40)(41)(42)(43)(44)(45)48,50). ...
... A total of 747 healthy men and women with an average age of 23.4 ± 3.0 yr participated in the included studies. Seventeen studies compared low-versus high-load resistance training (2,5,6,33,34,36,38,39,(42)(43)(44)(45)(46)(49)(50)(51)53), four compared lowversus moderate-load (35,40,47,52), five compared moderateversus high-load (7,32,37,41,48), and two studies compared low-versus moderate-versus high-load (3,4 (3)(4)(5)(6)(7)32,(35)(36)(37)(38)(39)43,44,49,50), followed by 8 studies assessing the upper limbs (4,7,32,34,45,47,48,50) and 5 studies assessing the whole body (e.g., dual-energy x-ray absorptiometry) (33,40,42,46,53), whereas lower-body muscle strength was assessed in 20 studies (3)(4)(5)(6)(7)32,33,35,(38)(39)(40)(41)(42)(43)(44)46,48,(50)(51)(52), followed by 12 studies assessing upper-body muscle strength (2,4,7,33,40,41,43,45,47,48,50,51), all using the 1-RM test. Eighteen studies reported the total volume performed during the intervention (4,5,7,(32)(33)(34)(35)(37)(38)(39)(40)(41)(42)(43)(44)(45)48,50). ...
... A total of 747 healthy men and women with an average age of 23.4 ± 3.0 yr participated in the included studies. Seventeen studies compared low-versus high-load resistance training (2,5,6,33,34,36,38,39,(42)(43)(44)(45)(46)(49)(50)(51)53), four compared lowversus moderate-load (35,40,47,52), five compared moderateversus high-load (7,32,37,41,48), and two studies compared low-versus moderate-versus high-load (3,4 (3)(4)(5)(6)(7)32,(35)(36)(37)(38)(39)43,44,49,50), followed by 8 studies assessing the upper limbs (4,7,32,34,45,47,48,50) and 5 studies assessing the whole body (e.g., dual-energy x-ray absorptiometry) (33,40,42,46,53), whereas lower-body muscle strength was assessed in 20 studies (3)(4)(5)(6)(7)32,33,35,(38)(39)(40)(41)(42)(43)(44)46,48,(50)(51)(52), followed by 12 studies assessing upper-body muscle strength (2,4,7,33,40,41,43,45,47,48,50,51), all using the 1-RM test. Eighteen studies reported the total volume performed during the intervention (4,5,7,(32)(33)(34)(35)(37)(38)(39)(40)(41)(42)(43)(44)(45)48,50). ...
Purpose: To analyse the effect of resistance training (RT) performed until volitional failure with low-, moderate- and high-loads on muscle hypertrophy and muscle strength in healthy adults; and assess the possible participant-, design-, and training-related covariates which may affect the adaptations.
Methods: Using PRISMA guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (>15 RM), moderate- (9-15 RM), and high-load (≤8 RM) RT were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardised mean difference (SMD) between RT loads in overall and subgroup analysis involving studies deemed high-quality. Associations between participant-, design-, and training-related covariates with SMD's were assessed by univariate and multivariate network meta-regression analysis.
Results: Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P= .113 - .469) or subgroup analysis (P= .871 - .995), greater effects were observed in untrained participants (P= .033), and participants with some training background who undertook more RT sessions (P= .031 - .045). Muscle strength improvement was superior for both high-load and moderate-load compared to low-load RT in overall and subgroup analysis (SMD= 0.60 - 0.63 and 0.34 - 0.35, respectively; P< .001 - .003), with a non-significant but superior effect for high- compared to moderate-load (SMD= 0.26 - 0.28, P= .068).
Conclusion: While muscle hypertrophy improvements appear to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy while undertaking more RT sessions provides superior gains in those with previous training experience.
... Accordingly, to the best of our knowledge, no data support the notion that subjects should reach concentric failure in every set of an RT session for maximize muscle activation (11,33). In fact, a study compared the effects of RT performed to concentric failure or to volitional interruption (i.e., point in which participants voluntarily interrupted the exercise prior to concentric failure) (34). Results showed that the use of high loads led to similar muscle activation regardless of reaching concentric failure (34). ...
... In fact, a study compared the effects of RT performed to concentric failure or to volitional interruption (i.e., point in which participants voluntarily interrupted the exercise prior to concentric failure) (34). Results showed that the use of high loads led to similar muscle activation regardless of reaching concentric failure (34). Altogether, microvascular oxygenation status does not seem to be the sole variable to modulate muscle activation, whereas other factors such as RT intensity (19,34) and level of fatigue (42) may modulate muscle activation. ...
... Results showed that the use of high loads led to similar muscle activation regardless of reaching concentric failure (34). Altogether, microvascular oxygenation status does not seem to be the sole variable to modulate muscle activation, whereas other factors such as RT intensity (19,34) and level of fatigue (42) may modulate muscle activation. ...
Metabolic stress is a primary mechanism of muscle hypertrophy and is associated with microvascular oxygenation and muscle activation. Considering that drop-set (DS) and crescent pyramid (CP) resistance training systems are recommended to modulate these mechanisms related to muscle hypertrophy, we aimed to investigate if these resistance training systems produce a different microvascular oxygenation status and muscle activation from those observed in traditional resistance training (TRAD). Twelve volunteers had their legs randomized in an intra-subject cross-over design in TRAD (3 sets of 10 repetitions at 75% 1-RM), DS (3 sets of ∼50-75% 1-RM) and CP (3 sets of 6-10 repetitions at 75-85% 1-RM). Vastus medialis microvascular oxygenation and muscle activation were respectively assessed by non-invasive near-infrared spectroscopy and surface electromyography techniques during the resistance training sessions in the leg-extension exercise. Total hemoglobin area under the curve (AUC) (TRAD: -1653.5 ± 2866.5; DS: -3069.2 ± 3429.4; CP: -1196.6 ± 2675.3) and tissue oxygen saturation (TRAD: 19283.1 ± 6698.0; DS: 23995.5 ± 15604.9; CP: 16109.1 ± 8553.1) increased without differences between protocols (p>0.05). Greater decreases in oxygenated hemoglobin AUC and hemoglobin differentiated AUC were respectively found for DS (-4036.8 ± 2698.1; -5004.4 ± 2722.9) compared with TRAD (-1951.8 ± 1720.0; -2250.3 ± 1305.7) and CP (-1814.4 ± 2634.3; 2432.2 ± 2891.4) (p<0.03). Higher increases of hemoglobin deoxygenated AUC were found for DS (1426.7 ± 1320.7) compared with TRAD (316.0 ± 1164.9) only (p=0.04). No differences were demonstrated in electromyographic amplitudes between TRAD (69.0 ± 34.4), DS (61.3 ± 26.7) and CP (60.9 ± 38.8) (p>0.05). Despite DS produced lower microvascular oxygenation levels compared with TRAD and CP, all protocols produced similar muscle activation levels.
... Indeed, several studies have shown that RTF did not induce additional muscle strength gains compared with RTNF in young trained and untrained populations (12,13,25,26,35,48), whereas a smaller number of studies observed greater strength increase after RTF (8,15,47). In addition, it seems that RTF does not induce further muscle size enhancements in young (35,40,48) and older individuals (53), although this outcome is less investigated. Regarding muscle power output, it has been shown that RTF may compromise muscle power improvements in highly trained athletes (25,26), whereas another study has shown similar muscle power adaptations between RTF and RTNF in older adults (2). ...
... Notwithstanding, this study only addressed maximal strength, and analyses on muscle hypertrophy and muscle power output adaptations were not performed. In addition, since the publication of this work (6), several other articles on this topic have been published, providing more data on the comparison between failure and not to failure approaches during RT (2,12,35,40,53). ...
... Maximal Dynamic Strength: Meta-Analysis and Subgroup Analysis. Data on maximal strength were obtained from 12 studies (8,9,13,25,26,30,35,40,(47)(48)(49)53) comprising a total of 384 individuals. In the overall analysis, no difference was found between changes induced by RTF and RTNF (SMD: 20.08; 95% CI: 20.42, 0.26; p 5 0.642; I 2 : 67.3%) ( Figure 2). ...
The aim of this review was to summarize the evidence from longitudinal studies assessing the effects induced by resistance training (RT) performed to failure (RTF) vs. not to failure (RTNF) on muscle strength, hypertrophy, and power output in adults. Three electronic databases were searched using terms related to RTF and RTNF. Studies were eligible if they met the following criteria: randomized and nonrandomized studies comparing the effects of RTF vs. RTNF on muscle hypertrophy, maximal strength, and muscle power in adults, and RT intervention ≥6 weeks. Results were presented as standardized mean differences (SMDs) between treatments with 95% confidence intervals, and calculations were performed using random effects models. Significance was accepted when p < 0.05. Thirteen studies were included in this review. No difference was found between RTF and RTNF on maximal strength in overall analysis (SMD: -0.08; p = 0.642), but greater strength increase was observed in RTNF considering nonequalized volumes (SMD: -0.34; p = 0.048). Resistance training performed to failure showed a greater increase in muscle hypertrophy than RTNF (SMD: 0.75; p = 0.005), whereas no difference was observed considering equalized RT volumes. No difference was found between RTF and RTNF on muscle power considering overall analysis (SMD: -0.20; p = 0.239), whereas greater improvement was observed in RTNF considering nonequalized RT volumes (SMD: -0.61; p = 0.025). Resistance training not to failure may induce comparable or even greater improvements in maximal dynamic strength and power output, whereas no difference between RTF vs. RTNF is observed on muscle hypertrophy, considering equalized RT volumes.
... Indeed, several studies have shown that RTF did not induce additional muscle strength gains compared with RTNF in young trained and untrained populations (12,13,25,26,35,48), whereas a smaller number of studies observed greater strength increase after RTF (8,15,47). In addition, it seems that RTF does not induce further muscle size enhancements in young (35,40,48) and older individuals (53), although this outcome is less investigated. Regarding muscle power output, it has been shown that RTF may compromise muscle power improvements in highly trained athletes (25,26), whereas another study has shown similar muscle power adaptations between RTF and RTNF in older adults (2). ...
... Notwithstanding, this study only addressed maximal strength, and analyses on muscle hypertrophy and muscle power output adaptations were not performed. In addition, since the publication of this work (6), several other articles on this topic have been published, providing more data on the comparison between failure and not to failure approaches during RT (2,12,35,40,53). ...
... Maximal Dynamic Strength: Meta-Analysis and Subgroup Analysis. Data on maximal strength were obtained from 12 studies (8,9,13,25,26,30,35,40,(47)(48)(49)53) comprising a total of 384 individuals. In the overall analysis, no difference was found between changes induced by RTF and RTNF (SMD: 20.08; 95% CI: 20.42, 0.26; p 5 0.642; I 2 : 67.3%) ( Figure 2). ...
Concurrent training (CT) is an efficient strategy to improve neuromuscular function and cardiorespiratory fitness in older adults, which are factors of pivotal importance for the maintenance of functional capacity with aging. However, there is a lack of evidence about the effectiveness of power training (PT) as an alternative to traditional strength training (TST) during CT. Thus, the aim of the present study was to examine the effect of 16 weeks (twice weekly) TST combined with high intensity interval training (TST + HIIT) vs. PT combined with HIIT (PT + HIIT) on functional performance, cardiorespiratory fitness and body composition in older men. Thirty five older men (65.8 ± 3.9 years) were randomly allocated into two training groups: TST + HIIT (n = 18), and PT + HIIT (n = 17). TST + HIIT performed resistance training at intensities ranging from 65% to 80% 1RM at slow controlled speed (≅ 2 s for each concentric phase), whereas PT + HIIT trained at intensities ranging from 40% to 60% of 1RM at maximal intentional speed. Both groups performed HIIT at intensities ranging from 75 to 90% of VO2peak. Participants performed functional tests (sit-to-stand, timed-up-and-go, stair climbing); cardiopulmonary exercise testing (maximal cycling power output: Wmax, peak oxygen uptake: VO2peak, cycling economy), as well as body composition assessment (DXA) before, post 8 and post 16 weeks of training. The groups improved similarly (P < 0.05) with training in all functional capacity outcomes, Wmax, cycling economy, VO2peak and body composition (P < 0.05). These findings suggest that HIIT based CT programs involving TST vs. PT are equally effective in improving functionality, cardiorespiratory fitness and body composition in healthy older men.
... A widely recommended strategy to mitigate the aging-related alterations in muscle morphology and functional performance is the regular practice of resistance training (RT) (1). It is known that RT may maximize muscle strength gains and hypertrophy even using low-load protocols (e.g., ,50% of 1 repetition maximum [1RM]), as long as the exercise is performed to muscle failure (20,36). However, exercising to the point of muscle failure acutely exacerbates blood pressure raises (14). ...
... In fact, the American College of Sports Medicine recommends nonfailure RT protocols for older adults, which should be performed until a substantial fatigue is installed (1,2). In this sense, our group demonstrated that RTinduced muscle strength gains and hypertrophy are similar between failure vs. nonfailure protocols in young individuals (i.e., the point in which subjects voluntarily interrupted the exercise before muscular failure), even with lower muscle fatigue (i.e., lower decrease in performance throughout the sets) and number of repetitions induced by nonfailure protocols (10,20). In fact, it could represent an important strategy for older adults, once significant adaptations may be obtained through a nonfailure RT protocol. ...
... Although performing repetitions in proximity to muscle failure seems to be an interesting strategy for older adults, a significant training volume may be produced (i.e., number of repetitions) (20), which might not be aligned to the recommendations for older adults in early stages of RT (2). In this sense, another nonfailure RT strategy that may represent an attractive strategy for previously untrained older individuals is the application of low loads with a fixed low number of repetitions (i.e., far from muscle failure). ...
Bergamasco, JGA, Gomes da Silva, D, Bittencourt, DF, Martins de Oliveira, R, Júnior, JCB, Caruso, FC, Godoi, D, Borghi-Silva, A, and Libardi, CA. Low-load resistance training performed to muscle failure or near muscle failure does not promote additional gains on muscle strength, hypertrophy, and functional performance of older adults. J Strength Cond Res XX(X): 000-000, 2020-The aim of the present study was to compare the effects of low-load resistance training (RT) protocols performed to failure (FAI), to voluntary interruption (VOL), and with a fixed low repetitions (FIX) on muscle strength, hypertrophy, and functional performance in older adults. Forty-one subjects (60-77 years) were randomized into one of the RT protocols (FAI, VOL, or FIX) and completed 12 weeks of RT at 40% of 1 repetition maximum (1RM), twice a week. The assessments included 1RM test, muscle cross-sectional area (CSA), rate of torque development (RTD), and functional performance (chair stand [CS], habitual gait speed [HGS], maximal gait speed [MGS], and timed up-and-go [TUG]). All protocols significantly increased 1RM values from Pre (FAI: 318.3 ± 116.3 kg; VOL: 342.9 ± 93.7 kg; FIX: 328.0 ± 107.2 kg) to Post (FAI: 393.0 ± 143.1 kg, 23.5%; VOL: 423.0 ± 114.5 kg, 23.3%; FIX: 397.8 ± 94.6 kg, 21.3%; p < 0.0001 for all groups). Regarding CS, all protocols showed significant improvements from Pre (FAI: 11.5 ± 2.4 seconds; VOL: 12.1 ± 2.5 seconds; FIX: 11.3 ± 1.1 seconds) to Post (FAI: 10.5 ± 1.1 seconds, -8.5%, p = 0.001; VOL: 10.3 ± 1.5 seconds, -15.1%, p = 0.001; FIX: 11.0 ± 1.1, -3.2%, p = 0.001). Habitual gait speed values increased significantly from Pre (FAI: 1.3 ± 0.2 m·s; VOL: 1.3 ± 0.1 m·s; FIX: 1.3 ± 0.1 m·s) to Post (FAI: 1.4 ± 0.2 m·s, 2.5%, p = 0.03; VOL: 1.4 ± 0.2 m·s, 5.2%, p = 0.036; FIX: 1.4 ± 0.1 m·s, 5.7%, p = 0.03). No significant differences between protocols were found (p > 0.05). In addition, there were no significant changes in CSA, RTD, MGS, and TUG for any protocols (p > 0.05). In conclusion, low-load RT performed without muscle failure promotes significant improvements in muscle strength and some parameters of functional performance in older adults.
... This study was conducted as a secondary analysis of some of the data published in Nóbrega et al. (13) and Barcelos et al. (2). These studies shared a similar population (i.e., untrained healthy young men) and design, with 1RM and CSA assessments occurring after the same number of training sessions. ...
... Data from each subject within each of the designated groups from these previous studies were analyzed with intent to examine raw data in an unbiased manner. Thus, the 14 subjects from Nóbrega et al. (13) submitted to highintensity resistance training to failure (HIRT-F) were considered a group, and the group name was modified to %1RM. Similarly, the 10 subjects from Barcelos et al. (2) submitted to resistance training at a 9-12 repetition maximum zone 3 times per week (RT3) were conserved as a group and renamed to RM Zone. ...
... Load adjustments were made according to each study's protocol. For the purpose of this secondary analysis, only the groups HIRT-F, from Nóbrega et al. (13), and RT3, from Barcelos et al. (2), were selected because they shared the same number of training sessions (24 sessions), relative load (;80% 1RM), and performed repetitions to concentric muscle failure. An overview of the experimental design and each group's protocol characteristics can be seen in Figure 1. ...
... Previous studies have provided partial support for Delorme's hypothesis, underpinning what is currently accepted as theory [11,12]. Although some guidelines suggest the use of high and moderate loads to development maximal strength and muscle hypertrophy, several studies showed increases in maximal strength and muscle hypertrophy after resistance training with low loads (i.e., <60% 1RM) [13][14][15][16][17]. These studies are in line with recent guidelines indicating that the athletic population may achieve comparable muscle hypertrophy across a wide spectrum of loading zones [18]. ...
... Reports not retrieved (n = 0) Table 2 shows the characteristics of the participants in the 23 studies that were selected for systematic review regarding the sample size, age, height, weight, and training status (mean ± SD) of the 563 participants, where 454 were untrained (80.6%) [11,[14][15][16][17][21][22][23]26,28,29,[38][39][40][41][42][43][44][45] and 109 were recreationally trained (19.4%) [13,46,47] in resistance training. Table 3 shows the characteristics of the studies that were selected for the systematic review regarding the study design, time of analysis, resistance exercise(s), prescription, weekly frequency, movement tempo, volume, and findings. ...
... Table 3 shows the characteristics of the studies that were selected for the systematic review regarding the study design, time of analysis, resistance exercise(s), prescription, weekly frequency, movement tempo, volume, and findings. Regarding the assessment of maximal strength development, 13 studies assessed dynamic strength using 1RM (56.5%) [11,[13][14][15]17,[21][22][23]29,44,[46][47][48] and another four studies assessed the isometric strength (17.4%) [26,38,39,45]. In addition, five studies simultaneously assessed dynamic strength using 1RM and isometric strength using a maximal voluntary isometric contraction (MVIC) (21.7%) [16,28,[41][42][43], and, finally, one study assessed isometric strength using maximal isometric voluntary torque (4.4%) [40]. ...
The load in resistance training is considered to be a critical variable for neuromuscular adaptations. Therefore, it is important to assess the effects of applying different loads on the development of maximal strength and muscular hypertrophy. The aim of this study was to systematically review the literature and compare the effects of resistance training that was performed with low loads versus moderate and high loads in untrained and trained healthy adult males on the development of maximal strength and muscle hypertrophy during randomized experimental designs. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (2021) were followed with the eligibility criteria defined according to participants, interventions, comparators, outcomes, and study design (PICOS): (P) healthy males between 18 and 40 years old, (I) interventions performed with low loads, (C) interventions performed with moderate or high loads, (O) development of maximal strength and muscle hypertrophy, and (S) randomized experimental studies with between-or within-subject parallel designs. The literature search strategy was performed in three electronic databases (Embase, PubMed, and Web of Science) on 22 August 2021. Results: Twenty-three studies with a total of 563 participants (80.6% untrained and 19.4% trained) were selected. The studies included both relative and absolute loads. All studies were classified as being moderate-to-high methodological quality, although only two studies had a score higher than six points. The main findings indicated that the load magnitude that was used during resistance training influenced the dynamic strength and isometric strength gains. In general, comparisons between the groups (i.e., low, moderate, and high loads) showed higher gains in 1RM and maximal voluntary isometric contraction when moderate and high loads were used. In contrast, regarding muscle hypertrophy, most studies showed that when resistance training was performed to muscle failure, the load used had less influence on muscle hypertrophy. The current literature shows that gains in maximal strength are more pronounced with high and moderate loads compared to low loads in healthy adult male populations. However, for muscle hypertrophy, studies indicate that a wide spectrum of loads (i.e., 30 to 90% 1RM) may be used for healthy adult male populations. Citation: Lacio, M.; Vieira, J.G.; Trybulski, R.; Campos, Y.; Santana, D.; Filho, J.E.; Novaes, J.; Vianna, J.; Wilk, M. Effects of Resistance Training
... Although these recommendations are feasible at home, they require machines or free weights to exercise with moderate to high intensities. It has recently been reported that low intensity (e.g., 30-50% 1-RM) exercise sets performed to concentric muscle failure (i.e., inability to complete another repetition with appropriate form) or close to failure produces similar gains in muscle strength and mass as moderate and high intensities (e.g., 50-80% of the 1-RM) (Nobrega et al., 2018;Santanielo et al., 2020). These adaptations occur irrespective of the manipulation of additional training variables (e.g., repetition duration, type of contraction, or exercise) (Nobrega et al., 2018;Damas et al., 2019;Soligon et al., 2020). ...
... It has recently been reported that low intensity (e.g., 30-50% 1-RM) exercise sets performed to concentric muscle failure (i.e., inability to complete another repetition with appropriate form) or close to failure produces similar gains in muscle strength and mass as moderate and high intensities (e.g., 50-80% of the 1-RM) (Nobrega et al., 2018;Santanielo et al., 2020). These adaptations occur irrespective of the manipulation of additional training variables (e.g., repetition duration, type of contraction, or exercise) (Nobrega et al., 2018;Damas et al., 2019;Soligon et al., 2020). Determining whether individuals are exercising close to concentric muscle failure is straightforward. ...
... They should be instructed to interrupt the exercise set voluntarily, according to their perception of fatigue, before concentric muscular failure (Santanielo et al., 2020). In fact, it has been recently shown that from these instructions, individuals interrupt exercise sets between 1 and 3 repetitions before concentric muscle failure (Nobrega et al., 2018;Santanielo et al., 2020). Voluntary interruption is practical and can also be used when performing body weight, elastic resistance band, and suspension band exercises at home. ...
There is emerging evidence that decreased muscle mass and cardiorespiratory fitness (CRF) are associated with increased risk of cancer-related mortality. This paper aimed to present recommendations to prescribe effective and safe exercise protocols to minimize losses, maintain or even improve muscle mass, strength, and CRF of the cancer patients who are undergoing or beyond treatment during the COVID-19 era. Overall, we recommend performing exercises with bodyweight, elastic bands, or suspension bands to voluntary interruption (i.e., interrupt the exercise set voluntarily, according to their perception of fatigue, before concentric muscular failure) to maintain or increase muscle strength and mass and CRF during COVID-19 physical distancing. Additionally, rest intervals between sets and exercises (i.e., long or short) should favor maintaining exercise intensities between 50 and 80% of maxHR and/or RPE of 12. In an exercise program with these characteristics, the progression of the stimulus must be carried out by increasing exercise complexity, number of sets, and weekly frequency. With feasible exercises attainable anywhere, modulating only the work-to-rest ratio and using voluntary interruption, it is possible to prescribe exercise for a wide range of patients with cancer as well as training goals. Exercise must be encouraged; however, exercise professionals must be aware of the patient’s health condition even at a physical distance to provide a safe and efficient exercise program. Exercise professionals should adjust the exercise prescription throughout home confinement whenever necessary, keeping in mind that minimal exercise stimuli are beneficial to patients in poor physical condition.
... No differences between groups were detected (P > 0.05), suggesting repetition to muscular failure is not a premise. Nóbrega et al. (2018) examined resistance training where participants either had to perform to muscular failure or to the point where participants volitionally interrupted the exercise. The interventional period was 12 weeks and a within-subject design was applied, whereby 32 untrained men (23.0 ± 3.6 years) performed unilateral leg extension twice a week. ...
... In summary, the results from the cited studies show that lower loads can be equally effective as higher loads if RE is performed to muscular failure. However, the topic is still ambiguous as some studies showed benefits for accomplishing muscular failure during dynamic RE (Rooney et al., 1994;Drinkwater et al., 2005; while others reported no benefit (Sampson and Groeller, 2016;Martorelli et al., 2017;Nóbrega et al., 2018). ...
Skeletal muscle is one of the most important tissues of the human body. It comprises up to 40% of the body mass and is crucial to survival. Hence, the maintenance of skeletal muscle mass and strength is pivotal. It is well-established that resistance exercise provides a potent anabolic stimulus to increase muscle mass and strength in men and women of all ages. Resistance exercise consists of mechano-biological descriptors, such as load, muscle action, number of repetitions, repetition duration, number of sets, rest interval between sets, frequency, volitional muscular failure, and range of motion, which can be manipulated. Herein, we discuss the evidence-based contribution of these mechano-biological descriptors to muscle mass and strength.
... However, several studies have shown that ST performed with repetitions until concentric failure does not induce additional muscle strength and power output gains when compared to repetitions not to failure (i.e., submaximal repetitions per set) in young populations (Folland et al., 2002;Izquierdo et al., 2006;Izquierdo-Gabarren et al., 2010;Sampson and Groeller, 2016;Martorelli et al., 2017), whereas a fewer number of studies observed greater strength gains following repetitions to failure (Rooney et al., 1994;Drinkwater et al., 2005). In addition, it seems that ST with repetitions to failure (i.e., maximal repetitions per set) does not induce further muscle size gains in young subjects (Sampson and Groeller, 2016;Martorelli et al., 2017;Nóbrega et al., 2018), although its effects are less investigated. Notwithstanding, to the best of the authors' knowledge, no previous study has compared the performance of ST with repetitions to failure or not to failure (i.e., submaximal per set) in elderly populations. ...
... It is important to highlight that, as in the neuromuscular performance results (i.e., 1 RM, RTD, jump performance), repetitions to concentric failure did not induce additional enhancements in muscle hypertrophy, suggesting that the maximal effort per set does not stimulate further muscle size gains. Although the present study investigates different muscle groups, these results are in agreement with previous studies investigating young populations (Sampson and Groeller, 2016;Martorelli et al., 2017;Nóbrega et al., 2018). Using similar experimental design as the present study, Martorelli et al. (2017) have shown that only the groups that performed greater ST volumes (i.e., repetitions to concentric failure or not failure equalizing the ST volume by adding more sets) improved elbow flexor muscle thickness in young women. ...
This randomized clinical trial compared the neuromuscular adaptations induced by concurrent training (CT) performed with repetitions to concentric failure and not to failure in elderly men. Fifty-two individuals (66.2 ± 5.2 years) completed the pre- and post-measurements and were divided into three groups: repetitions to failure (RFG, n = 17); repetitions not to failure (NFG, n = 20); and repetitions not to failure with total volume equalized to RFG (ENFG, n = 15). Participants were assessed in isometric knee extension peak torque (PTiso), maximal strength (1RM) in the leg press (LP) and knee extension (KE) exercises, quadriceps femoris muscle thickness (QF MT), specific tension, rate of torque development (RTD) at 50, 100 and 250 ms, countermovement jump (CMJ) and squat jump (SJ) performance, as well as maximal neuromuscular activity (EMGmax) of the vastus lateralis (VL) and rectus femoris (RF) muscles. CT was performed over 12 weeks, twice weekly. Along with each specific strength training program, each group also underwent an endurance training in the same session. After training, all groups improved similarly and significantly in LP and KE 1RM, PTiso, CMJ and SJ performance, RTD variables, specific tension, and VL EMGmax, (P < 0.05-0.001). QF MT improved only in RFG and ENFG (P < 0.01). These results suggest that repetitions until concentric failure does not provide further neuromuscular performance gains and muscle hypertrophy, and that even a low number of repetitions relative to the maximal possible (i.e., 50%) optimizes neuromuscular performance in elderly men. Moreover, training volume appears to be more important for muscle hypertrophy than training using maximal repetitions.
... Controversy exists regarding the need for progressing training to failure to induce neuromuscular adaptation. Although some studies advocate that resistance exercise performed to failure may maximize muscle excitability and stimulate strength and muscle mass gains regardless of the exercise load or BFR (8,11,25,34), others suggest that high-load or low-load training performed to failure with free blood flow does not add benefits to muscle mass and strength gains in both untrained and trained subjects compared with nonfailure training (10, 28,33). This is a relevant discussion because LL-RT performed to failure could cause boredom and result in overtraining and musculoskeletal injury because of the repetitive effort (22,37). ...
... However, no differences in muscle mass and strength gains were observed in untrained individuals when training with LL-BFR was performed to failure or not, whereas nonfailure training led to reduced perceptions of exertion and discomfort and delayed onset of muscle soreness (36). Considering that it is unclear whether BFR training performed to failure is appropriate for trained subjects, it seems reasonable to propose that training near failure is sufficient to generate neuromuscular adaptation (10, 28,33). Based on this assumption and assuming that training to failure is expedited using high-BFR pressures, exercises performed with repetitions near failure and combined with high-BFR pressures will also require fewer repetitions. ...
Cerqueira, MS, Lira, M, Mendonça Barboza, JA, Burr, JF, Wanderley e Lima, TB, Maciel, DG, and De Brito Vieira, WH. Repetition failure occurs earlier during low-load resistance exercise with high but not low blood flow restriction pressures: a systematic review and meta-analysis. J Strength Cond Res XX(X): 000-000, 2021-High-load and low-load resistance training (LL-RT) performed to failure are considered effective for improving muscle mass and strength. Alternatively, LL-RT with blood flow restriction (LL-BFR) may accelerate repetition failure and has been suggested to be more time efficient than LL-RT. This study explores the evidence for the effects of LL-BFR vs. LL-RT on repetition failure. A systematic literature search was conducted in the PubMed, CINAHL, Web of Science, CENTRAL, Scopus, SPORTDiscus, and PEDro databases. Meta-analyses of mean differences and 95% confidence intervals (CIs) were performed using a random-effects model. Subgroup analyses were conducted for both the high and low blood flow restriction pressures. The search identified n = 10 articles that met the inclusion criteria. The meta-analysis comprised a total of 218 healthy subjects. Low-load resistance training with blood flow restriction with high pressures (≥50% arterial occlusion pressure [AOP]) precipitate repetition failure in ∼14.5 fewer repetitions (95% CI -19.53 to -9.38) compared with LL-RT, whereas the use of low pressures (<50% AOP) stimulated repetition failure with ∼1.4 fewer repetitions (95% CI -3.11 to 0.37); however, this difference was not statistically significant. Repetition failure has been demonstrated to be an important normalizing variable when comparing the hypertrophic and strength effects resulting from resistance training and occurs earlier during low-load resistance exercise with high but not low blood flow restriction pressures.
... On the other hand, several studies have demonstrated that low-load resistance exercises can also induce muscle hypertrophy when repetition until exhaustion is per-formed. It is suggested that training to failure can induce recruitment of FT fibers with lower training load [7][8][9][10][11] . However, the relationships between the muscle hypertrophic effects and training variables such as intensity, volume, and interval between sets remain unclear. ...
... Generally, it is considered that fatigue is necessary to acquire FT fiber recruitment during low-load resistance training [8][9][10][11] . By using this simple RT model, FT fiber recruitment for several training variables can be calculated. ...
A set of mathematical models for resistance training (RT model) with repeated dynamic and voluntary activations of knee extensor muscles was proposed and validated. RT model predicts muscle activity, fatigue and recovery, and can be used to predict the mechanical impulses identified in different muscle fiber types. Several resistance training program variables (e.g. load, velocity, number of sets, and duration of rest intervals) were addressed in this study. Experimental data from six subjects were taken under several different training protocols. For the protocols studied, the model precisely predicted the maximum number of repetitions during knee extension resistance exercise (R² = 0.87). This study demonstrates the applicability of the first simple mathematical model for voluntary dynamic exercise of knee extensor muscles. The developed model calculates the mechanical impulse of fast twitch fiber for the selected protocols. For instance, the model shows high intensity training tends to induce more fast-twitch fiber recruitment than that in low intensity training in the case of non-failure. This model is expected to help in understanding how impulses of different fiber types contribute and affect training.
... Muscle strength and training load has been studied by several studies (1,12,14). Drinkwater et al. (5) agreed that elite young athletes, who trained until muscle failure, obtained higher 6RM strength gains than training without bench press muscle failure. The results of the present study did not support this work, since, regardless of the exercise performed, no difference was found in strength gains and in the training load between the MAX and SUBMAX groups. ...
... The results of the present study did not support this work, since, regardless of the exercise performed, no difference was found in strength gains and in the training load between the MAX and SUBMAX groups. However, our results supported the results of other studies (8,12,14), with no differences in muscle strength, regardless of whether or not the subjects trained to failure. ...
The purpose of this study was to compare the effect of 8 wks of resistance training with or without failure on muscle strength, total training volume, rating perceived exertion, and estimated repetitions to failure. Eighteen trained men participated in the study. The training was performed for 3 non-consecutive days of the week for 8 wks. The subjects were randomly divided into 2 groups: (a) one group that trained until concentric muscle failure (MAX); and (b) the other group did not reach concentric muscle failure (SUBMAX). Both groups performed 3 sets of 10 repetitions. Muscle strength (1RM) and training load (10RM) were evaluated before (pre), after 4 wks (4W), and after 8 wks (8W). In addition, the total training volume (TTV), the rating perceived exertion (RPE), and the estimated repetitions to failure were verified. The results showed that 1RM and 10RM increased 4W and 8W (P<0.001), but without differences between groups (P>0.05). The TTV was similar between the groups with no significant difference (P>0.05). The RPE-muscle and RPE-overall was higher in the MAX group when compared to SUBMAX group (P<0.01), but the MAX group presented lower values of estimated repetitions to failure (P<0.01). In conclusion, both trainings were effective for increases in muscle strength and training load, but it seems that training to concentric muscle failure can lead to a greater sensation of muscle fatigue.
... % and PROT = 37.20 %) and muscle CSA (PROT + CHO = 14.73 % and PROT = 13.37 %) after 8 weeks of training, with no additional effect for CHO supplementation. These gains are in agreement with the literature, that shows similar increases in strength [33] and muscle mass [34] in studies with 6-12 weeks of RT in young untrained individuals. Regarding between groups comparisons, the similarity in muscle mass and strength gains between PROT + CHO and PROT protocols was possibly due to the similarity in TTV between groups. ...
... Regarding between groups comparisons, the similarity in muscle mass and strength gains between PROT + CHO and PROT protocols was possibly due to the similarity in TTV between groups. Evidence suggests that when TTV is equalized, similar neuromuscular adaptations are to be expected, regardless of training intensity [33,35] and training frequency [36]. Thus, the similar accumulated and progression in TTV between groups in our study could explain the similar increases in muscle strength and muscle mass between PROT + CHO and PROT. ...
The purpose was to compare the effects of protein (whey protein) and carbohydrate supplementation and protein alone both combined with resistance training on muscle strength, muscle mass and total training volume progression in untrained young men. Resistance training was performed using the leg press and knee extension until concentric failure (8−12 repetition maximum), three times a week for eight weeks. Muscle strength and muscle cross-sectional area were assessed before and after training. Total training volume progression was calculated considering the first and eighth week. Seventeen men completed the study (protein and carbohydrate, n=9, age 23.44 ± 4.56 years, weight: 62.13±6.17 kg, height: 1.75±0.02 m, body mass index: 20.29±2.08 kg/m2; protein, n=8, age 24.63±2.39 years, weight: 69.01±5.57 kg, height: 1.77±0.07 m; body mass index: 21.64±1.05 kg/m2. Both protocols showed similar increases in muscle strength (effect size: protein and carbohydrate=1.28; protein=0.97; p<0.001), muscle cross sectional area (effect size: protein and carbohydrate=0.66; protein=0.47; p<0.001) and total training volume progression (effect size: protein and carbohydrate=2.68; protein=1.63; p<0.001) after training. No differences were found between groups p>0.05). Protein and carbohydrate supplementation combined with resistance training does not induce greater gains in muscle strength, hypertrophy and total training volume compared to resistance training combined with protein alone in untrained individuals.
... Out of 21 young men invited to participate, 16 completed the experimental protocol (age: 24.8 6 5.6 years [range: [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], height: 174 6 0.04 cm, body mass: 75.3 6 8.4 kg, RT experience: 5.1 6 4.1 years, and CSA: 30.4 6 5.03 cm 2 ; mean 6 SD) totaling 32 legs. Three subjects dropped out due to personal reasons and 2 for injuries not related to the training protocols. ...
... A 2-minute rest interval was allowed between sets, with a 2-3 minutes rest between exercises. Repetitions were performed to the point of muscular failure (i.e., inability to perform another concentric repetition while maintaining proper form) (27). Loads were adjusted between sets whenever the subject performed a set outside the repetitions range, i.e., if the subject performed more than 12 repetitions, the load was increased in the next set; if the subject was not able to complete at least 8 repetitions, the load was reduced. ...
Scarpelli, MC, Nóbrega, SR, Santanielo, N, Alvarez, IF, Otoboni, GB, Ugrinowitsch, C, and Libardi, CA. Muscle hypertrophy response is affected by previous resistance training volume in trained individuals. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to compare gains in muscle mass of trained individuals after a resistance training (RT) protocol with standardized (i.e., nonindividualized) volume (N-IND), with an RT protocol using individualized volume (IND). In a within-subject approach, 16 subjects had one leg randomly assigned to N-IND (22 sets·wk, based on the number of weekly sets prescribed in studies) and IND (1.2 × sets·wk recorded in training logs) protocols. Muscle cross-sectional area (CSA) was assessed by ultrasound imaging at baseline (Pre) and after 8 weeks (Post) of RT, and the significance level was set at p < 0.05. Changes in the vastus lateralis CSA (difference from Pre to Post) were significantly higher for the IND protocol (p = 0.042; mean difference: 1.08 cm; confidence interval [CI]: 0.04-2.11). The inferential analysis was confirmed by the CI of the effect size (0.75; CI: 0.03-1.47). Also, the IND protocol had a higher proportion of individuals with greater muscle hypertrophy than the typical error of the measurement (chi-square, p = 0.0035; estimated difference = 0.5, CI: 0.212-0.787). In conclusion, individualizing the weekly training volume of research protocols provides greater gains in muscle CSA than prescribing a group standard RT volume.
... Regarding muscle mass and strength gains, although no study investigated the effects of ST in these neuromuscular adaptations in older adults, it is possible to suggest that the gains are comparable to TRT. It has been suggested that performing RT to concentric muscle failure (Jenkins et al. 2015;Schoenfeld et al. 2015) can maximize gains in muscle strength (Rooney et al. 1994;Drinkwater et al. 2005) and hypertrophy (Schott et al. 1995), due to the increase in the muscle activation, regardless of training variables manipulation or methods (Souza et al. 2014;Barcelos et al. 2018;Nobrega et al. 2018;Damas et al. 2019;Lasevicius et al. 2019). In fact, it has been recently shown that manipulation of load, time under tension and number of repetitions during RT resulted in similar muscle activation when exercises were performed to concentric muscle failure (Morton et al. 2019). ...
... Regarding muscle mass and strength, similar increases were found between TRT and ST performed to concentric muscle failure, confirming our initial hypothesis. Consistent with these results, we (Angleri et al. 2017;Nobrega et al. 2018;Damas et al. 2019) and others (Mitchell et al. 2012;Morton et al. 2016;Schoenfeld et al. 2017) have demonstrated similar muscle hypertrophy and strength gains between protocols performed to concentric muscle failure even when manipulating RT variables (e.g., load, volume, type of contraction or frequency) (Damas et al. 2019), training schemes (e.g., periodized vs. non-periodized) (Pelzer et al. 2017) and RT systems (e.g., TRT, drop-set or crescent pyramid) (Angleri et al. 2017). However, for muscle strength, similar gains are not universal. ...
PurposeWe compared the effects of suspension training (ST) with traditional resistance training (TRT) on muscle mass, strength and functional performance in older adults.Methods
Forty-two untrained older adults were randomized in TRT, ST (both performed 3 sets of whole body exercises to muscle failure) or control group (CON). Muscle thickness (MT) of biceps brachii (MTBB) and vastus lateralis (MTVL), maximal dynamic strength test (1RM) for biceps curl (1RMBC) and leg extension exercises (1RMLE), and functional performance tests (chair stand [CS], timed up and go [TUG] and maximal gait speed [MGS]) were performed before and after 12 weeks of training.ResultsMTBB increased significantly and similarly for all training groups (TRT 23.35%; ST 21.56%). MTVL increased significantly and similarly for all training groups (TRT 13.03%; ST 14.07%). 1RMBC increased significantly and similarly for all training groups (TRT 16.06%; ST 14.33%). 1RMLE increased significantly and similarly for all training groups (TRT 14.89%; ST 18.06%). MGS increased significantly and similarly for all groups (TRT 6.26%; ST 5.99%; CON 2.87%). CS decreased significantly and similarly for all training groups (TRT − 20.80%; ST − 15.73%). TUG decreased significantly and similarly for all training groups (TRT − 8.66%; ST − 9.16%).Conclusion
Suspension training (ST) promotes similar muscle mass, strength and functional performance improvements compared to TRT in older adults.
... Duration of the repetition (DR) and number of repetitions (NR) are some of the variables of RT (Kraemer and Ratamess, 2004) and attention has been given in order to understand their influence on EMG amplitude (Burd et al., 2012;Lacerda et al., 2016;Looney et al., 2016;Nóbrega et al., 2018). For instance, Burd et al. (2012) demonstrated a higher EMG amplitude when longer DR (12s) was used compared to shorter DR (2s) with the same NR. ...
The present study compared neuromuscular activation, measured by surface electromyography (EMG) amplitude [measure by EMG peak (EMGPEAK)] and range of motion (ROM) where EMGPEAK occurred between two training protocols, matched by time under tension, but with a different number and duration of repetitions. Sixteen recreationally trained males performed 2 training protocols with 3 sets, 180 s of rest with 60% of one-repetition maximum(1RM) on the bench press performed in a Smith machine. Protocol A consisted of 6 repetitions with a repetition duration of 6s and protocol B consisted of 12 repetitions with a repetition duration of 3s. EMG activity of anterior deltoid, pectoralis major and triceps brachii muscles were recorded. The results showed a general higher EMG amplitude (regardless of the muscle) in protocol B (p= 0.010), and pectoral and triceps brachii consistently presented higher neuromuscular activation than anterior deltoid at both protocols (p= 0.007). Additionally, the ROM where EMGPEAK occurred in triceps brachii was in the middle of the concentric action (~50% of ROM), this occurred in the first half of the same action (~24% of ROM) in the other muscles. In conclusion, protocol B demonstrated an increased EMG amplitude over protocol A, although both protocols responded similarly by achieving the highest EMG amplitude at same ROM among the muscles analysed.
... Em uma meta-análise, Schoenfeld et al. (2016b) intensidade, volume e frequência de TF) (BRAITH et al., 1989;CARROLL et al., 1998;PETERSON et al., 2004;CANDOW et al., 2007;KRIEGER, 2009;MITCHELL et al., 2012;GENTIL et al., 2015). et al., 1989;CARROLL et al., 1998;PETERSON et al., 2004;CANDOW et al., 2007;KRIEGER, 2009;MITCHELL et al., 2012;GENTIL et al., 2015), outros estudos verificaram que as adaptações musculares são similares apesar da diferença no VTT (OSTROWSKI et al., 1997;BOTTARO et al., 2011;MITCHELL et al., 2012;NOBREGA et al., 2017) . Por exemplo, Mitchell et al. (2012) INFANT HEARING, 2007;1995). ...
... Em uma meta-análise, Schoenfeld et al. (2016b) intensidade, volume e frequência de TF) (BRAITH et al., 1989;CARROLL et al., 1998;PETERSON et al., 2004;CANDOW et al., 2007;KRIEGER, 2009;MITCHELL et al., 2012;GENTIL et al., 2015). et al., 1989;CARROLL et al., 1998;PETERSON et al., 2004;CANDOW et al., 2007;KRIEGER, 2009;MITCHELL et al., 2012;GENTIL et al., 2015), outros estudos verificaram que as adaptações musculares são similares apesar da diferença no VTT (OSTROWSKI et al., 1997;BOTTARO et al., 2011;MITCHELL et al., 2012;NOBREGA et al., 2017) . Por exemplo, Mitchell et al. (2012) INFANT HEARING, 2007;1995). ...
... Em uma meta-análise, Schoenfeld et al. (2016b) (BRAITH et al., 1989;CARROLL et al., 1998;PETERSON et al., 2004;CANDOW et al., 2007;KRIEGER, 2009;MITCHELL et al., 2012;GENTIL et al., 2015). et al., 1989;CARROLL et al., 1998;PETERSON et al., 2004;CANDOW et al., 2007;KRIEGER, 2009;MITCHELL et al., 2012;GENTIL et al., 2015), outros estudos verificaram que as adaptações musculares são similares apesar da diferença no VTT (OSTROWSKI et al., 1997;BOTTARO et al., 2011;MITCHELL et al., 2012;NOBREGA et al., 2017) . Por exemplo, Mitchell et al. (2012) INFANT HEARING, 2007;2000;1995). ...
... However, based on the cited evidence, it must be highlighted that for low-load training to result in similar hypertrophic responses to heavier load training, a lifter must train to volitional fatigue. 31 Practitioners may prescribe ST training during rehabilitation programs or to develop connective tissue strength, as well as to improve control and body awareness. Indeed, it is interesting to note that the higher blood lactate concentrations induced by ST might represent an appropriate avenue for the stimulation of hypertrophic gains. ...
Purpose:
To examine the differences in muscle fatigability after resistance exercise performed with fast tempo (FT) compared with slow tempo (ST).
Methods:
A total of 8 resistance-trained males completed FT and ST hexagonal-barbell deadlifts, consisting of 8 sets of 6 repetitions at 60% 3-repetition maximum, using a randomized crossover design. Each FT repetition was performed with maximal velocity, while each repetition during ST was performed with a 3-1-3 (eccentric/isometric/concentric) tempo (measured in seconds). Isometric maximal voluntary contraction, voluntary muscle activation, and evoked potentiated twitch torque of the knee extensors were determined using twitch interpolation before, during (set 4), and after exercise. Displacement-time data were measured during the protocols.
Results:
The mean bar velocity and total concentric work were higher for FT compared with ST (995 [166] W vs 233 [52] W; 0.87 [0.05] m/s vs 0.19 [0.05] m/s; 4.8 [0.8] kJ vs 3.7 [1.1] kJ). Maximal voluntary contraction torque, potentiated twitch, and voluntary muscle activation were significantly reduced after FT (-7.8% [9.2%]; -5.2% [9.2%], -8.7% [12.2%]) and ST (-11.2% [8.4%], -13.3% [8.1%], -1.8% [3.6%]).
Conclusion:
The decline in maximal voluntary force after both the FT and ST hexagonal-barbell deadlifts exercise was accompanied by a similar decline in contractile force and voluntary muscle activation.
... This is suggested as the affective responses became less positive when training to failure or reaching an RPE/RIR $9.4 6 1.1. In addition, research has shown that not training to failure is slightly better than training to failure for improving strength (8) and just as beneficial for improving muscular size (28). Furthermore, it has been shown that training to failure results in greater fatigue and longer-lasting decrements in performance (32). ...
Cavarretta, DJ, Hall, EE, and Bixby, WR. The effects of increasing training load on affect and perceived exertion. J Strength Cond Res XX(X): 000-000, 2019-This study was designed to investigate how affect and ratings of perceived exertion based on repetitions in reserve (RPE/RIR) change as a function of increasing load during a 10 repetition maximum (RM) test. Twenty-nine novice lifters completed a 10RM test for 2 different conditions presented in a randomized, counterbalanced fashion. RPE/RIR and affect were assessed immediately after each successful 10RM attempt. RPE/RIR was significantly different at all loads from 50 to 100% 10RM (p < 0.001) with no differences between exercise and exercise load (p = 0.059). RPE/RIR was higher for all lower body exercises compared with upper-body exercises (p < 0.001) but was not different between machine and free-weight exercises (p > 0.344). Affect became less positive only at 100% 10RM compared with all other loads (p < 0.05). Finally, affect was more positive for upper-body exercises compared to lower-body exercises (p = 0.025) and more positive for machines compared to free-weights (p = 0.015). The results of this study suggest that among novice lifters, RPE/RIR increases as load increases during a 10RM and affective valence remains relatively constant but becomes less positive when exercising at maximal intensities (100% 10RM). Further research is needed to replicate these findings and elucidate the effects of different muscles used (e.g., upper vs. lower body) and modality of exercise (e.g., machine vs. free-weight) on RPE/RIR and affect among both novice and experienced lifters.
... All participants start doing the exercises using bodyweight and the volitional interruption method is used in order to achieve the benefits of resistance training and to reduce the risk of musculoskeletal injuries. 35 The loads are gradually increased until the participant can adequately perform 12 repetitions with no voluntary interruption due to muscle fatigue. ...
Introduction
There is an unmet need to develop tailored therapeutic exercise protocols applying different treatment parameters and modalities for individuals with knee osteoarthritis (KOA). Cryotherapy is widely used in rehabilitation as an adjunct treatment due to its effects on pain and the inflammatory process. However, disagreement between KOA guidelines remains with respect to its recommendation status. The aim of this study is to verify the complementary effects of cryotherapy when associated with a tailored therapeutic exercise protocol for patients with KOA.
Methods and analysis
This study is a sham-controlled randomised trial with concealed allocation and intention-to-treat analysis. Assessments will be performed at baseline and immediately following the intervention period. To check for residual effects of the applied interventions, 3-month and 6-month follow-up assessments will be performed. Participants will be community members living with KOA divided into three groups: (1) the experimental group that will receive a tailored therapeutic exercise protocol followed by a cryotherapy session of 20 min; (2) the sham control group that will receive the same regimen as the first group, but with sham packs filled with dry sand and (3) the active treatment control group that will receive only the therapeutic exercise protocol. The primary outcome will be pain intensity according to a Visual Analogue Scale. Secondary outcomes will be the Western Ontario & McMaster Universities Osteoarthritis Index; the Short-Form Health Survey 36; the 30-s Chair Stand Test; the Stair Climb test; and the 40-m fast-paced walk test.
Ethics and dissemination
The trial was approved by the Institutional Ethics Committee of Federal University of São Carlos, São Paulo, Brazil. Registration approval number: CAAE: 65966617.9.0000.5504. The results will be published in peer-reviewed journals.
Trial registration number
NCT03360500
... In order to increment the load and achieve the benefits of resistance training, the volitional interruption method is used, providing a low risk of musculoskeletal injuries to the participants. 36 The participants start using no loads, which are gradually increased (by 1 kg for free weights or by the elastic band resistance) until they are able to adequately perform 12 repetitions with no voluntary interruption due to muscle fatigue. ...
Background
Physical exercise, a cornerstone of the conservative management of knee osteoarthritis (KOA), is exhaustively recommended by important clinical guidelines. A strength therapeutic exercise program (STEP) relieves pain, improves physical function and ultimately ameliorates quality of life (QoL). Furthermore, photobiomodulation (PBM) has been used as an adjunct treatment for people with KOA; however, there are still controversial recommendations regarding its use on this population. Thus, we hypothesised that PBM, when associated with a STEP protocol on patients with KOA, could induce better clinical outcomes than a STEP protocol alone.
Methods and analysis
The study is a 6-month triple-blind placebo-controlled randomised clinical trial with intention-to-treat analysis. The trial will include 120 people with clinic and radiographic signs of KOA. The intervention consists of a supervised STEP and PBM protocols conducted over an 8-week intervention period. Assessments are performed at baseline, right after treatment, and 3-month and 6-month follow-up periods. The primary clinical outcome is pain intensity according to a 10 cm Visual Analogue Scale. Secondary outcomes are the global Western Ontario & McMaster Universities Osteoarthritis Index; QoL assessed by the 36-item Short-Form health survey questionnaire; and performance-based physical parameters assessed by the 30 s chair stand test; the stair climb test; and the 40 m fast-paced walk test.
Ethics and dissemination
The trial was approved by the Human Research Ethics Committee of the Federal University of São Carlos, São Paulo, Brazil (REC no 2.016.122). Results will be published in peer-reviewed journals.
Trial registration number
Brazilian Clinical Trials Registry (U1111-1215-6510).
... Strength gains made through RT have been observed alongside alterations within muscle morphology and architecture (Reeves et al., 2004;Alegre et al., 2006;Franchi et al., 2014;Kim et al., 2015;Nóbrega et al., 2018). Muscles with fibers running parallel to tendons are said to have a longitudinal architectural arrangement, which differs from muscles in which fibers orientate at an angle to the direction of force generation (unipennate), or at more than one angle (multi-pennate) (Lieber and Fridén, 2000). ...
Measurement of muscle specific contractile properties in response to resistance training (RT) can provide practitioners valuable information regarding physiological status of individuals. Field based measurements of such contractile properties within specific muscle groups, could be beneficial when monitoring efficacy of training or rehabilitation interventions. Tensiomyography (TMG) quantifies contractile properties of individual muscles via an electrically stimulated twitch contraction and may serve as a viable option in the aforementioned applications. Thus, aims of this study were; (i) to investigate the potential use of TMG to quantify training adaptations and differences, in response to exercise specific lower limb RT; and (ii) investigate any associations between TMG parameters and accompanying muscle architectural measures. Non-resistance trained male participants (n = 33) were randomly assigned to 1 of 3 single-exercise intervention groups (n = 11 per group); back squat (BS), deadlift (DL), or hip thrust (HT). Participants completed a 6-week linearized training program (2× per week), where the assigned exercise was the sole method of lower body training. Pre- and post-intervention testing of maximal dynamic strength was assessed by one repetition maximum (1RM) of BS, DL, and HT. Radial muscle belly displacement (Dm) and contraction time (Tc) were obtained via TMG from the rectus femoris (RF) and vastus lateralis (VL) pre- and post-intervention, alongside muscle architectural measures (pennation angle and muscle thickness). All three groups displayed significant increases all 1RM strength tests (p < 0.001; pη2 = 0.677–0.753). Strength increases were accompanied by significant overall increases in RF muscle thickness (p < 0.001, pη2 = 0.969), and pennation angle (p = 0.007, pη2 = 0.220). Additionally, an overall reduction in RF Dm (p < 0.001, pη2 = 0.427) was observed. Significant negative relationships were observed between RF Dm and pennation angle (p = 0.003, r = −0.36), and with RF Dm and muscle thickness (p < 0.001, r = −0.50). These findings indicate that TMG is able to detect improved contractile properties, alongside improvements in muscle function within an untrained population. Furthermore, the observed associations between Dm and muscle architecture suggest that TMG contractile property assessments could be used to obtain information on muscle geometry.
... When comparing failure with non-failure training for muscle hypertrophy, some studies have reported significantly greater or more favorable effect sizes with failure training [10,11] while others favor nonfailure training [12,13]. Still other studies reported no significant group differences [5,14] for muscle hypertrophy. Similar to hypertrophy, studies on muscle strength have observed greater improvements with failure training [15,16] while others have observed effect sizes in favor of nonfailure training [17,18], and yet others show no significant difference between failure and non-failure [5,11,19,20]. ...
Resistance training variables such as volume, load, and frequency are well defined. However, the variable proximity to failure does not have a consistent quantification method, despite being defined as the number of repetitions in reserve (RIR) upon completion of a resistance training set. Further, there is between-study variability in the definition of failure itself. Studies have defined failure as momentary (inability to complete the concentric phase despite maximal effort), volitional (self-termination), or have provided no working definition. Methods to quantify proximity to failure include percentage-based prescription, repetition maximum zone training, velocity loss, and self-reported RIR; each with positives and negatives. Specifically, applying percentage-based prescriptions across a group may lead to a wide range of per-set RIR owing to interindividual differences in repetitions performed at specific percentages of 1 repetition maximum. Velocity loss is an objective method; however, the relationship between velocity loss and RIR varies set-to-set, across loading ranges, and between exercises. Self-reported RIR is inherently individualized; however, its subjectivity can lead to inaccuracy. Further, many studies, regardless of quantification method, do not report RIR. Consequently, it is difficult to make specific recommendations for per-set proximity to failure to maximize hypertrophy and strength. Therefore, this review aims to discuss the strengths and weaknesses of the current proximity to failure quantification methods. Further, we propose future directions for researchers and practitioners to quantify proximity to failure, including implementation of absolute velocity stops using individual average concentric velocity/RIR relationships. Finally, we provide guidance for reporting self-reported RIR regardless of the quantification method.
... 5,6 When TUT or load are manipulated, changes in neuromuscular activation occur. [7][8][9] Sakamoto and Sinclair 9 simultaneously manipulated both TUT (exercise to failure) and load, which resulted in higher muscular activation when a lower TUT and higher load were used. Similarly, Schoenfeld et al. 10 compared higher vs. lower load RT to failure, and found that higher loads and lower TUT resulted in higher muscle activation. ...
Objectives
Despite advancements in resistance training (RT) methods, the acute physiological responses to time under tension (TUT) and load on acute metabolic and neuromuscular responses remains poorly understood. The aim of the present study was to investigate how TUT or resistance load impact muscular activation and blood lactate during an RT session.
Design
A randomized cross-over design.
Methods
Participants performed a squat exercise in three different conditions: baseline protocol (BPRO; three sets of eight repetitions with four second repetitions at 60% of 1RM) long duration protocol (LDPRO: six second repetitions) and high load protocol (HLPRO: 70% 1RM).
Results
Muscular activation of the vastus lateralis and biceps femoris, and blood lactate were assessed. Blood lactate was ∼19% and ∼26% higher after set one and three in LDPRO compared to BPRO (P ≤ 0.011) and ∼17% higher for LDPRO compared to HLPRO (P = 0.002). Additionally, blood lactate was ∼17% higher for HLPRO compared to BPRO after the third set of exercise (P = 0.003). Vastus lateralis activation was ∼10% higher for HLPRO compared to BPRO and LDPRO for sets one and two. Biceps femoris activation was ∼17% higher for HLPRO compared to BPRO for set one (P = 0.023) while for set two HLPRO was greater than BPRO and LDPRO (∼19% and ∼14%, respectively; P ≤ 0.007).
Conclusions
Squatting with higher TUT caused a greater impact on the metabolic responses than lower TUT or higher loads, whereas an increase in training load resulted in greater muscle activation than higher TUT or lower training load.
... Training protocols performed to muscle failure (MF) have been employed in an attempt to maximize activation and neuromuscular fatigue responses [1][2][3] . MF is defined as the inability to perform the full range of motion (ROM) of a repetition due to fatigue 4 . ...
Resistance training protocols performed to muscle failure (MF) have been employed in an attempt to maximize activation and neuromuscular fatigue. Therefore, the aim of this study was to compare the surface electromyography amplitude (EMGRMS) and frequency (EMGFREQ) of the pectoralis major between protocols performed to MF and non muscle failure (NMF). Seven trained men performed three sets at 60% of a repetition maximum, with a 3 min rest period and a 6s repetition duration. MF protocol was performing with maximum number of repetitions in all sets, while in NMF protocol subjects performed 6 repetitions in 3 sets. For data analysis two two-way repeated measures ANOVAs (Protocol x Repetition) were used and when necessary, Bonferroni post hoc was performed. The EMGRMS was higher in the protocol MF compare to NMF, but there was no difference in EMGFREQ between protocols. Although there were no significant differences in the frequency domain between protocols, perform repetitions to MF was a determining factor to generate higher amplitude of the electromyography signal. Thus, perform repetitions to MF could be considered an effective strategy to increase muscle activation in trained individuals, however, with similar neuromuscular fatigue.
... Current exercise prescription guidelines indicate that RTinduced gains in muscle mass are obtained by performing multiple sets of 3-12 RM (70-100% 1-RM) (depending on training status) [53,54]. Recently, mounting evidence suggests that low-intensity RT (20-50% 1-RM), performed close to concentric failure, produces similar gains in muscle mass to high-intensity RT [57,58]. Thus, effort duration, rest interval, and skeletal muscle metabolic demand seem to be similar between hypertrophy-oriented RT and all four HIIT prescription zones, indicating that the gains in muscle mass should not be affected by HIIT-based CT protocols. ...
Previous research has suggested that concurrent training (CT) may attenuate resistance training (RT)-induced gains in muscle strength and mass, i.e.‚ the interference effect. In 2000, a seminal theoretical model indicated that the interference effect should occur when high-intensity interval training (HIIT) (repeated bouts at 95–100% of the aerobic power) and RT (multiple sets at ~ 10 repetition maximum;10 RM) were performed in the same training routine. However, there was a paucity of data regarding the likelihood of other HIIT-based CT protocols to induce the interference effect at the time. Thus, based on current HIIT-based CT literature and HIIT nomenclature and framework, the present manuscript updates the theoretical model of the interference phenomenon previously proposed. We suggest that very intense HIIT protocols [i.e., resisted sprint training (RST), and sprint interval training (SIT)] can greatly minimize the odds of occurring the interference effect on muscle strength and mass. Thus, very intensive HIIT protocols should be implemented when performing CT to avoid the interference effect. Long and short HIIT-based CT protocols may induce the interference effect on muscle strength when HIIT bout is performed before RT with no rest interval between them.
... This is not to say that it is a requirement to train to a maximal intensity of effort (i.e., to momentary failure) to produce adaptation, or that doing so is necessarily optimal; indeed, findings regarding this are conflicting (Davies et al., 2016). Recently, it has also been shown that during high effort but non-momentary failure training there are similar adaptations irrespective of load and that these may even be similar to when training to momentary failure (Nóbrega et al., 2018). It is not clear what the dose-response nature of proximity to failure and thus effort is, or whether a threshold phenomenon might exist to optimize adaptation . ...
Prolonged periods in microgravity (μG) environments result in deconditioning of numerous physiological systems, particularly muscle at molecular, single fiber, and whole muscle levels. This deconditioning leads to loss of strength and cardiorespiratory fitness. Loading muscle produces mechanical tension with resultant mechanotransduction initiating molecular signaling that stimulates adaptations in muscle. Exercise can reverse deconditioning resultant from phases of detraining, de-loading, or immobilization. On Earth, applications of loading using exercise models are common, as well as in μG settings as countermeasures to deconditioning. The primary modalities include, but are not limited to, aerobic training (or “cardio”) and resistance training, and have historically been dichotomized; the former primarily thought to improve cardiorespiratory fitness, and the latter primarily improving strength and muscle size. However, recent work questions this dichotomy, suggesting adaptations to loading through exercise are affected by intensity of effort independent of modality. Furthermore, similar adaptations may occur where sufficient intensity of effort is used. Traditional countermeasures for μG-induced deconditioning have focused upon engineering-based solutions to enable application of traditional models of exercise. Yet, contemporary developments in understanding of the applications, and subsequent adaptations, to exercise induced muscular loading in terrestrial settings have advanced such in recent years that it may be appropriate to revisit the evidence to inform how exercise can used in μG. With the planned decommissioning of the International Space Station as early as 2024 and future goals of manned moon and Mars missions, efficiency of resources must be prioritized. Engineering-based solutions to apply exercise modalities inevitably present issues relating to devices mass, size, energy use, heat production, and ultimately cost. It is necessary to identify exercise countermeasures to combat deconditioning while limiting these issues. As such, this brief narrative review considers recent developments in our understanding of skeletal muscle adaptation to loading through exercise from studies conducted in terrestrial settings, and their applications in μG environments. We consider the role of intensity of effort, comparisons of exercise modalities, the need for concurrent exercise approaches, and other issues often not considered in terrestrial exercise studies but are of concern in μG environments (i.e., O2 consumption, CO2 production, and energy costs of exercise).
... It is known that muscle hypertrophy increases pennation angles. 30,31 The variable morphology of the proximal aponeurosis of the long head of the biceps femoris should also be considered. 32 This means that, in some instances, the semitendinosus muscle may originate at the muscular portion of the biceps femoris or on its proximal aponeurosis. ...
Hamstring muscle injuries are the most prevalent among athletes who engage in sprinting activities. Their most frequent location is where the long head of the biceps femoris joins with the semitendinosus muscle to form the conjoint hamstring tendon. Just distal to this area an additional group of fibers of the semitendinosus originate from medial aspect of biceps femoris. The objective of this study was to analyze the morphological characteristics of this union and to discuss its potential role in hamstring tears.
Anatomical dissection was performed on 35 thighs. Samples obtained from this region were sectioned and stained with Masson’s trichrome for further histological evaluation.
A group of fibers from the semitendinosus muscle originating from the long head of the biceps femoris were observed in all 35 specimens. This origin was located 67 ± 12mm from the ischial tuberosity and was 32 ± 14mm in length. This group of muscle fibers had a width of 10.9 ± 5.3mm and a thickness in the anteroposterior axis of 3.2 ± 1.4mm. Its pennation angle was 9.2 ± 1.5 degrees. Microscopic examination showed muscle cells from both muscles contacting interposed tendinous tissue.
In conclusion, fibers of the semitendinosus muscle consistently arise from the proximal aspect of the long head of biceps femoris. The morphological characteristics of this junction have functional implications. The horizontal component of the semitendinosus vector could pull the long head of the biceps femoris medially during its shortening—lengthening cycle, rendering it an intrinsic risk factor for hamstring injuries.
... Previous research has shown that handgrip strength is not the best indicator of physical performance (Abe et al., 2016) and that applying 1RM would have been a more representative outcome metric in calculating MQ. In another study by Nóbrega and colleagues (Nobrega et al., 2018), young men (average age: 23.0 years old) participated in two days per week of unilateral leg extension RET for 12 weeks at 30% and 80% 1RM. Following both 6 (midpoint) and 12 weeks (post-training) of exercise, similar improvements in 1RM muscle strength, muscle CSA, and pennation angle were observed. ...
Muscle quality (MQ), defined as the amount of strength and/or power per unit of muscle mass, is a novel index of functional capacity that is increasingly relied upon as a critical biomarker of muscle health in low functioning aging and pathophysiological adult populations. Understanding the phenotypical attributes of MQ and how to use it as an assessment tool to explore the efficacy of resistance exercise training interventions that prioritize functional enhancement over increases in muscle size may have implications for populations beyond compromised adults, including healthy young adults who routinely perform physically demanding tasks for competitive or occupational purposes. However, MQ has received far less attention in healthy young populations than it has in compromised adults. Researchers and practitioners continue to rely upon static measures of lean mass or isolated measures of strength and power, rather than using MQ, to assess integrated functional responses to resistance exercise training and physical stress. Therefore, this review will critically examine MQ and the evidence base to establish this metric as a practical and important biomarker for functional capacity and performance in healthy, young populations. Interventions that enhance MQ, such as high-intensity stretch shortening contraction resistance exercise training, will be highlighted. Finally, we will explore the potential to leverage MQ as a practical assessment tool to evaluate function and enhance performance in young populations in non-traditional research settings.
• In the case of both low- and high-intensity resistance training (RT), fitness professionals should teach their clients to lift near failure without achieving complete momentary muscular failure (MMF), as indicated by a ratings of perceived exertion value of 8 to 9 or repetitions in reserve value of 1 to 2. • MMF and volitional interruption (VI) elicit comparable improvements in strength and hypertrophy at high intensities (75% to 85% 1RM), so both may be integrated into a single training session (i.e., 4 sets of bench press, first three performed to VI, final set to MMF). • Program failure training to align with your client's goals — performing RT sets to failure — may be more effective for hypertrophy, whereas nonfailure sets may be more beneficial for power.
Background:
low-moderate intensity strength training to failure increases strength and muscle hypertrophy in healthy people. However, no study assessed the safety and neuromuscular response of training to failure in people with severe haemophilia (PWH). The purpose of the study was to analyse neuromuscular responses, fear of movement, and possible adverse effects in PWH, after knee extensions to failure.
Methods:
twelve severe PWH in prophylactic treatment performed knee extensions until failure at an intensity of five on the Borg CR10 scale. Normalised values of amplitude (nRMS) and neuromuscular fatigue were determined using surface electromyography for the rectus femoris, vastus medialis, and vastus lateralis. After the exercise, participants were asked about their perceived change in fear of movement, and to report any possible adverse effects.
Results:
Patients reported no adverse effects or increased fear. The nRMS was maximal for all the muscles before failure, the median frequency decreased, and wavelet index increased during the repetitions. The vastus lateralis demonstrated a higher maximum nRMS threshold and earlier fatigue, albeit with a lower and more progressive overall fatigue.
Conclusions:
severe PWH with adequate prophylactic treatment can perform knee extensions to task failure using a moderate intensity, without increasing fear of movement, or adverse effects.
The purpose of this paper was to conduct a systematic review and meta-analysis of studies that compared muscle hypertrophy and strength gains between resistance training protocols employing very low (VLL<30% of 1RM or >35 RM), low (LL30%-59% of 1RM, or 16–35 RM), moderate (ML60%-79% of 1RM, or 8 -15RM) and high load (HL≥80% of 1RM, or ≤7 RM) with matched volume loads (sets x reps x weight). A pooled analysis of the standardized mean difference for 1RM strength outcomes across the studies showed a benefit favoring HL vs. LL and vs. ML; and favoring ML vs. LL. Results from LL and VLL indicated little difference. A pooled analysis of the standardized mean difference for hypertrophy outcomes across all studies showed no differences between the training loads. Our findings indicate that, when volume load is equated between conditions, the highest loads induce superior dynamic strength gains. Alternatively, hypertrophic adaptations are similar irrespective of the magnitude of load. NOVELTY BULLETS: • Training with higher loads elicits greater gains in 1RM muscle strength when compared to lower loads, even when volume load is equated between conditions. • Muscle hypertrophy is similar irrespective of the magnitude of load, even when volume load is equated between conditions.
Introdução: Desordens musculoesqueléticas são comuns e podem comprometer a função, o desempenho físico e a qualidade de vida. Dentre as intervenções utilizadas no manejo de desordens musculoesqueléticas, as modalidades de restrição de fluxo sanguíneo (RFS) vêm ganhando espaço na literatura científica. Objetivos: Essa tese teve o propósito de investigar os aspectos fisiológicos, os métodos de prescrição e as aplicações clínicas de modalidades de RFS em diferentes desordens musculoesqueléticas. Métodos e resultados: As modalidades de RFS consideradas foram a RFS passiva (sem exercício concomitante), o pré-condicionamento isquêmico (PCI) e a RFS combinada ao exercício. Como desordens musculoesqueléticas foram consideradas condições que causassem prejuízo funcional, tais como perda de força e de massa muscular, dano muscular induzido por exercício, fadiga muscular e osteoartrite (OA) de joelho. A presente tese é composta por introdução, três capítulos referentes às modalidades de RFS, e considerações finais. Os capítulos 1, 2 e 3 versam, respectivamente, sobre RFS passiva, PCI e RFS combinada ao exercício, e são compostos de sete artigos científicos envolvendo três desenhos de estudo: revisão sistemática (com e sem meta-análise), revisão narrativa e ensaio clínico aleatorizado. O capítulo 1 é uma revisão sistemática (artigo 1) sobre os efeitos da RFS passiva para minimizar perdas de força e de massa muscular (hipotrofia por desuso) em indivíduos submetidos a restrições na descarga de peso em membros inferiores. No capítulo 1 observamos que embora potencialmente útil, o alto risco de viés apresentado nos estudos originais limita a indicação de RFS passiva como modalidade eficaz contra a redução de força e de massa muscular induzida por imobilismo. O capítulo 2 é um ensaio clínico controlado e aleatorizado (artigo 2) que investigou os efeitos do PCI na proteção contra o dano muscular induzido por exercício (DMIE) em pessoas saudáveis. O artigo 2 apontou que o PCI não foi superior ao sham para proteger contra o DMIE. O capítulo 3 aborda aspectos fisiológicos, metodológicos e clínicos da RFS combinada ao exercício físico. O primeiro manuscrito do capítulo 3 (artigo 3) é uma revisão sistemática com meta-análise que analisou a excitação muscular (por eletromiografia de superfície) durante exercício resistido com RFS. O artigo 3 indicou que a excitação muscular durante o exercício de baixa carga com RFS foi maior que durante exercício de carga pareada sem RFS somente quando a falha muscular não foi alcançada. Adicionalmente, exercício de baixa carga com RFS apresentou menor excitação muscular que exercício de alta carga, independentemente de alcançar ou não a falha voluntária. O segundo manuscrito do capítulo 3 (artigo 4) é uma revisão sistemática com meta-análise que mostrou uma
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antecipação da falha muscular durante exercícios de baixa carga com altas pressões de RFS, mas não com baixas pressões. O terceiro manuscrito do capítulo 3 (artigo 5) é uma revisão narrativa que discute a possível necessidade de ajustar a pressão de RFS ao longo das semanas de treinamento. No artigo 5 observamos que a literatura é contraditória, o que dificulta recomendar se tais ajustes na pressão de RFS são necessários. O artigo 6 é um protocolo de ensaio clínico aleatorizado proposto para investigar os efeitos do exercício de baixa carga e volume total reduzido com RFS versus treinamento de alta carga sem RFS no tratamento da OA de joelho. O artigo 7 é o ensaio clínico aleatorizado que apresenta os resultados do protocolo (artigo 6) e mostrou que o treinamento de baixa carga com volume total reduzido e com RFS teve efeito similar ao treinamento de alta carga sem RFS na dor no joelho, desempenho muscular, função física e qualidade de vida de pacientes com OA de joelho, embora a magnitude nos ganhos de força tenha sido maior após treino de alta carga. Conclusões: De forma geral, com exceção do PCI para proteger contra o DMIE, as modalidades de RFS são potencialmente úteis no manejo das disfunções musculoesqueléticas aqui estudadas. Adicionalmente, concluímos que é necessário avançar no entendimento dos mecanismos fisiológicos e no estudo dos métodos de prescrição das diferentes modalidades de restrição de fluxo sanguíneo.
Loading recommendations for resistance training are typically prescribed along what has come to be known as the “repetition continuum”, which proposes that the number of repetitions performed at a given magnitude of load will result in specific adaptations. Specifically, the theory postulates that heavy load training optimizes increases maximal strength, moderate load training optimizes increases muscle hypertrophy, and low-load training optimizes increases local muscular endurance. However, despite the widespread acceptance of this theory, current research fails to support some of its underlying presumptions. Based on the emerging evidence, we propose a new paradigm whereby muscular adaptations can be obtained, and in some cases optimized, across a wide spectrum of loading zones. The nuances and implications of this paradigm are discussed herein.
The manipulation of resistance training (RT) variables is used among athletes, recreational exercisers and compromised populations (e.g., elderly) attempting to potentiate muscle hypertrophy. However, it is unknown whether an individual's inherent predisposition dictates the RT-induced muscle hypertrophic response. Twenty resistance-trained young (26(3)y) men performed 8wk unilateral RT (2∙wk ⁻¹ ) with one leg randomly assigned to a standard progressive RT (CON), and the contralateral leg to a variable RT (VAR, modulating exercise load, volume, contraction type and interset rest interval). The VAR leg completed all 4 RT variations every 2wk. Bilateral vastus lateralis cross-sectional area (CSA) was measured pre- and post-RT, and acute integrated myofibrillar protein synthesis (MyoPS) rates were assessed at rest and over 48h following the final RT session. Muscle CSA increase was similar between CON and VAR (P>0.05), despite higher total training volume (TTV) in VAR (P<0.05). The 0-48h integrated MyoPS increase post-exercise was slightly greater for VAR than CON (P<0.05). All participants were considered 'responders' to RT, although none benefited to a greater extent from a specific protocol. Between-subjects variability (MyoPS, 3.30%; CSA, 37.8%) was 40-fold greater than the intra-subject (between legs) variability (MyoPS, 0.08%; CSA, 0.9%). The higher TTV and greater MyoPS response in VAR did not translate to a greater muscle hypertrophic response. Manipulating common RT variables elicited similar muscle hypertrophy than a standard progressive-RT program in trained young men. Intrinsic individual factors are key determinants of the MyoPS and change in muscle CSA compared with extrinsic manipulation of common RT variables.
Muscle strength is often measured through the performance of a one-repetition maximum (1RM). However, we that feel a true measurement of ‘strength’ remains elusive. For example, low-load alternatives to traditional resistance training result in muscle hypertrophic changes similar to those resulting from traditional high-load resistance training, with less robust changes observed with maximal strength measured by the 1RM. However, when strength is measured using a test to which both groups are ‘naive’, differences in strength become less apparent. We suggest that the 1RM is a specific skill, which will improve most when training incorporates its practice or when a lift is completed at a near-maximal load. Thus, if we only recognize increases in the 1RM as indicative of strength, we will overlook many effective and diverse alternatives to traditional high-load resistance training. We wish to suggest that multiple measurements of strength assessment be utilized in order to capture a more complete picture of the adaptation to resistance training.
Background:
In this study, we investigated the effects of resistance training protocols with different loads on muscle hypertrophy and strength.
Methods:
Twenty-one participants were randomly assigned to 1 of 3 (n = 7 for each) resistance training (RT) protocols to failure: High load 80 % 1RM (8-12 repetitions) (H group), low load 30 % 1RM (30-40 repetitions) (L group) and a mixed RT protocol (M group) in which the participants switch from H to L every 2 weeks. RT consisted of three sets of unilateral preacher curls performed with the left arm 3 times/week with 90 s rest intervals between sets. The right arm served as control. Maximum voluntary contraction (MVC) of the elbow flexors (elbow angle: 90°) and rate of force development (RFD, 0-50, 50-100, 100-200 and 200-300 ms) were measured. Cross-sectional area (CSA) of the elbow flexors was measured via magnetic resonance imaging (MRI). All measurements were conducted before and after the 8 weeks of RT (72-96 h after the last RT). Statistical evaluations were performed with two-way repeated measures (time × group).
Results:
After 8 weeks of 3 weekly RT sessions, significant increases in the left elbow flexor CSA [H: 9.1 ± 6.4 % (p = 0.001), L: 9.4 ± 5.3 % (p = 0.001), M: 8.8 ± 7.9 % (p = 0.001)] have been observed in each group, without significant differences between groups. Significant changes in elbow flexor isometric MVC have been observed in the H group (26.5 ± 27.0 %, p = 0.028), while no significant changes have been observed in the M (11.8 ± 36.4 %, p = 0.26) and L (4.6 ± 23.9 %, p = 0.65) groups. RFD significantly increased during the 50-100 ms phase in the H group only (p = 0.049).
Conclusions:
We conclude that, as long as RT is conducted to failure, training load might not affect muscle hypertrophy in young men. Nevertheless, strength and RFD changes seem to be load-dependent. Furthermore, a non-linear RT protocol switching loads every 2 weeks might not lead to superior muscle hypertrophy nor strength gains in comparison with straight RT protocols.
We reported, using a unilateral resistance training (RT) model, that training with high or low loads (mass per repetition) resulted in similar muscle hypertrophy and strength improvements in RT-naïve subjects. Here we aimed to determine whether the same was true in men with previous RT experience using a whole-body RT program and whether post-exercise systemic hormone concentrations were related to changes in hypertrophy and strength. Forty-nine resistance-trained men (mean ± SEM, 23 ± 1 y) performed 12 wk of whole-body RT. Subjects were randomly allocated into a higher-repetition (HR) group who lifted loads of ~30-50% of their maximal strength (1RM) for 20-25 repetitions/set (n=24) or a lower-repetition (LR) group (~75-90% 1RM, 8-12 repetitions/set, n=25), with all sets being performed to volitional failure. Skeletal muscle biopsies, strength testing, DXA scans, and acute changes in systemic hormone concentrations were examined pre- and post-training. In response to RT, 1RM strength increased for all exercises in both groups (p < 0.01), with only the change in bench press being significantly different between groups (HR: 9 ± 1 vs. LR: 14 ±1 kg, p = 0.012). Fat- and bone-free (lean) body mass, type I and type II muscle fibre cross sectional area increased following training (p < 0.01) with no significant differences between groups. No significant correlations between the acute post-exercise rise in any purported anabolic hormone and the change in strength or hypertrophy were found. In congruence with our previous work, acute post-exercise systemic hormonal rises are not related to or in any way indicative of RT-mediated gains in muscle mass or strength. Our data show that in resistance-trained individuals load, when exercises are performed to volitional failure, does not dictate hypertrophy or, for the most part, strength gains.
Background
It remains unclear whether repetitions leading to failure (failure training) or not leading to failure (non-failure training) lead to superior muscular strength gains during resistance exercise. Failure training may provide the stimulus needed to enhance muscular strength development. However, it is argued that non-failure training leads to similar increases in muscular strength without the need for high levels of discomfort and physical effort, which are associated with failure training.
Objective
We conducted a systematic review and meta-analysis to examine the effect of failure versus non-failure training on muscular strength.
Methods
Five electronic databases were searched using terms related to failure and non-failure training. Studies were deemed eligible for inclusion if they met the following criteria: (1) randomised and non-randomised studies; (2) resistance training intervention where repetitions were performed to failure; (3) a non-failure comparison group; (4) resistance training interventions with a total of ≥3 exercise sessions; and (5) muscular strength assessment pre- and post-training. Random-effects meta-analyses were performed to pool the results of the included studies and generate a weighted mean effect size (ES).
Results
Eight studies were included in the meta-analysis (combined studies). Training volume was controlled in four studies (volume controlled), while the remaining four studies did not control for training volume (volume uncontrolled). Non-failure training resulted in a 0.6–1.3 % greater strength increase than failure training. A small pooled effect favouring non-failure training was found (ES = 0.34; p = 0.02). Significant small pooled effects on muscular strength were also found for non-failure versus failure training with compound exercises (ES = 0.37–0.38; p = 0.03) and trained participants (ES = 0.37; p = 0.049). A slightly larger pooled effect favouring non-failure training was observed when volume-uncontrolled studies were included (ES = 0.41; p = 0.047). No significant effect was found for the volume-controlled studies, although there was a trend favouring non-failure training. The methodological quality of the included studies in the review was found to be moderate. Exercise compliance was high for the studies where this was reported (n = 5), although limited information on adverse events was provided.
Conclusion
Overall, the results suggest that despite statistically significant effects on muscular strength being found for non-failure compared with failure training, the small percentage of improvement shown for non-failure training is unlikely to be meaningful. Therefore, it appears that similar increases in muscular strength can be achieved with failure and non-failure training. Furthermore, it seems unnecessary to perform failure training to maximise muscular strength; however, if incorporated into a programme, training to failure should be performed sparingly to limit the risks of injuries and overtraining.
The purpose of this study was to investigate electromyographic amplitude (EMG AMP), EMG mean power frequency (MPF), exercise volume (VOL), total work and muscle activation (iEMG), and time under concentric load (TUCL) during, and muscle cross-sectional area (mCSA) before and after 3 sets to failure at 80 vs. 30 % 1RM resistance exercise.
Nine men (mean ± SD, age 21.0 ± 2.4 years, resistance training week(-1) 6.0 ± 3.7 h) and 9 women (age 22.8 ± 3.8 years, resistance training week(-1) 3.4 ± 3.5 h) completed 1RM testing, followed by 2 experimental sessions during which they completed 3 sets to failure of leg extension exercise at 80 or 30 % 1RM. EMG signals were collected to quantify EMG AMP and MPF during the initial, middle, and last repetition of each set. Ultrasound was used to assess mCSA pre- and post-exercise, and VOL, total work, iEMG, and TUCL were calculated.
EMG AMP remained greater at 80 % than 30 % 1RM across all reps and sets, despite increasing 74 and 147 % across reps at 80 and 30 % 1RM, respectively. EMG MPF decreased across reps at 80 and 30 % 1RM, but decreased more and was lower for the last reps at 30 than 80 % 1RM (71.6 vs. 78.1 % MVIC). mCSA increased more from pre- to post-exercise for 30 % (20.2-24.1 cm(2)) than 80 % 1RM (20.3-22.8 cm(2)). VOL, total work, iEMG and TUCL were greater for 30 % than 80 % 1RM.
Muscle activation was greater at 80 % 1RM. However, differences in volume, metabolic byproduct accumulation, and muscle swelling may help explain the unexpected adaptations in hypertrophy vs. strength observed in previous studies.
The purpose of this study was to compare the effect of low- versus high-load resistance training (RT) on muscular adaptations in well-trained subjects. Eighteen young men experienced in RT were matched according to baseline strength, and then randomly assigned to 1 of 2 experimental groups: a low-load RT routine (LL) where 25-35 repetitions were performed per set per exercise (n = 9), or a high-load RT routine (HL) where 8-12 repetitions were performed per set per exercise (n = 9). During each session, subjects in both groups performed 3 sets of 7 different exercises representing all major muscles. Training was carried out 3 times per week on non-consecutive days, for 8 total weeks. Both HL and LL conditions produced significant increases in thickness of the elbow flexors (5.3 vs. 8.6%, respectively), elbow extensors (6.0 vs. 5.2%, respectively), and quadriceps femoris (9.3 vs. 9.5%, respectively), with no significant differences noted between groups. Improvements in back squat strength were significantly greater for HL compared to LL (19.6 vs. 8.8%, respectively) and there was a trend for greater increases in 1RM bench press (6.5 vs. 2.0%, respectively). Upper body muscle endurance (assessed by the bench press at 50% 1RM to failure) improved to a greater extent in LL compared to HL (16.6% vs. -1.2%, respectively). These findings indicate that both HL and LL training to failure can elicit significant increases in muscle hypertrophy among well-trained young men; however, HL training is superior for maximizing strength adaptations.
This investigation sought to determine the effect of resistance training to failure on functional, structural and neural elbow flexor muscle adaptation. Twenty-eight males completed a 4-week familiarization period and were then counterbalanced on the basis of responsiveness across; non-failure rapid shortening (RS; rapid concentric, 2 s eccentric), non-failure stretch-shortening (SSC; rapid concentric, rapid eccentric), and failure control (C, 2 s concentric, 2 s eccentric), for a 12-week unilateral elbow flexor resistance training regimen, 3 × week using 85% of one repetition maximum (1RM). 1RM, maximal voluntary contraction (MVC), muscle cross-sectional area (CSA), and muscle activation (EMGRMS ) of the agonist, antagonist, and stabilizer muscles were assessed before and after the 12-week training period. The average number of repetitions per set was significantly lower in RS 4.2 [confidence interval (CI): 4.2, 4.3] and SSC 4.2 (CI: 4.2, 4.3) compared with C 6.1 (CI: 5.8, 6.4). A significant increase in 1RM (30.5%), MVC (13.3%), CSA (11.4%), and agonist EMGRMS (22.1%) was observed; however, no between-group differences were detected. In contrast, antagonist EMGRMS increased significantly in SSC (40.5%) and C (23.3%), but decreased in RS (13.5%). Similar adaptations across the three resistance training regimen suggest repetition failure is not critical to elicit significant neural and structural changes to skeletal muscle.
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Purpose
It has been hypothesized that lifting light loads to muscular failure will activate the full spectrum of MUs and thus bring about muscular adaptations similar to high-load training. The purpose of this study was to investigate EMG activity during low- versus high-load training during performance of a multi-joint exercise by well-trained subjects.
Methods
Employing a within-subject design, 10 young, resistance-trained men performed sets of the leg press at different intensities of load: a high-load (HL) set at 75 % of 1-RM and a low-load (LL) set at 30 % of 1-RM. The order of performance of the exercises was counterbalanced between participants, so that half of the subjects performed LL first and the other half performed HL first, separated by 15 min rest. Surface electromyography (EMG) was used to assess mean and peak muscle activation of the vastus medialis, vastus lateralis, rectus femoris, and biceps femoris.
Results
Significant main effects for trials and muscles were found (p
The content of this manuscript is intended to assist the reader in collecting valid and reliable data for quantifying muscular strength and power. Various drawbacks and pitfalls of specific tests, as well as recommendations for the practitioner are also provided. The content is divided into sections covering isometric, isotonic, field tests, and isokinetic modes of exercise. Inherent in these modes are both concentric and eccentric muscle actions as well as both open and closed kinetic chain activities. For Isometric testing, contractions should occur over a four to five seconds duration with a one second transition period at the start of the contraction. At least one minute of rest should be provided between contractions. For each muscle tested at each position, at least three contractions should be performed although more may be performed if deemed necessary by the tester. For isotonic testing, the 1-RM test should be performed. After the general warm-up, the subject should perform a specific warm-up set of 8 repetitions at approximately 50% of the estimated 1-RM followed by another set of 3 repetitions at 70% of the estimated 1-RM. Subsequent lifts are single repetitions of progressively heavier weights until failure. Repeat until the 1-RM is determined to the desired level of precision. The rest interval between sets should be not less than one and not more than five minutes. The optimal number of single repetitions ranges from three to five. Data and guidelines of the following field tests are also provided; vertical jump, bench press, Wingate anaerobic cycle test (WAT), and the Margaria stair-run test. For isokinetic testing, details are provided for testing peak torque, work, power, endurance, and estimation of fiber type percentages.
We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 ± 1 yr, 22.6 ± 2.1 kg/m(2); means ± SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 ± 1.8%, 80%-1 = 3.2 ± 0.8%, and 80%-3= 7.2 ± 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.
We aimed to determine the effect of resistance exercise intensity (%1 repetition maximum-1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression.
Fifteen men (21+/-1 years; BMI=24.1+/-0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P=0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P=0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P=0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition.
These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.
1. The purpose of the study was to examine the dependence of neuromuscular propagation impairment on the level of isometric force sustained to the endurance limit. The task involved human volunteers sustaining a submaximal abduction force with the index finger by activating the first dorsal interosseous muscle as long as possible. 2. The submaximal force was sustained at one of three levels (20, 35 or 65% of maximum) by increasing motor unit activity, as indicated by the electromyogram (EMG), during the fatiguing contraction. Although the EMG increased during the fatiguing contraction, the EMG was significantly less than maximum at the endurance limit for all subjects (deficit of 19-55% of maximum). This deficit was inversely related to the level of the sustained submaximal force. 3. The maximum voluntary contraction and twitch forces were significantly reduced following the fatiguing contraction. As with the EMG, the degree of force reduction was greatest for the subjects who sustained the low target forces. 4. The fatiguing contraction caused a 12-23% decline in M wave amplitude, a 33-51% increase in M wave duration, and no change in M wave area. The decline in M wave amplitude, which is an index of neuromuscular propagation impairment, was greatest among the subjects who sustained the low target forces. 5. The mean power frequency of the EMG decreased by a similar amount (50-57%) during the fatiguing contraction for all three groups of subjects. 6. A model representing the interaction of processes that enhance and impair force was developed to explain the recovery of twitch force following the sustained contractions at different target forces. 7. We conclude that the fatigue experienced by a subject when force is sustained at a submaximal value does involve an impairment of neuromuscular propagation. This impairment is one factor that limits muscle excitation during a submaximal, fatiguing contraction and contributes to the diminished force capability by the end of the fatigue task.
The role of intramuscular metabolite changes in the adaptations following isometric strength training was examined by comparing the effect of short, intermittent contractions (IC) and longer, continuous (CC) contractions. In a parallel study, the changes in phosphate metabolites and pH were examined during the two protocols using whole-body nuclear magnetic resonance spectroscopy (NMRS). Seven subjects trained three time per week for 14 weeks. The right leg was trained using four sets of ten contractions, each lasting 3 s with a 2-s rest period between each contraction and 2 min between each set. The left leg was trained using four 30-s contractions with a 1-min rest period between each. Both protocols involved isometric contractions at 70% of a maximum voluntary isometric contraction (MVC). The MVC, length:tension and force:velocity relationships and cross-sectional area (CSA) of each leg were measured before and after training. The increase in isometric strength was significantly greater (P = 0.041) for the CC leg (median 54.7%; P = 0.022) than for IC (31.5%; P = 0.022). There were no significant differences between the two protocols for changes in the length:tension or force:velocity relationships. There were significant increases in muscle CSA for the CC leg only. NMRS demonstrated that the changes in phosphate metabolites and pH were greater for the CC protocol. These findings suggest that factors related to the greater metabolite changes during CC training results in greater increases in isometric strength and muscle CSA.
High resistance training enhances muscular strength, and recent work has suggested an important role for metabolite accumulation in this process.
To investigate the role of fatigue and metabolite accumulation in strength gains by comparing highly fatiguing and non-fatiguing isotonic training protocols.
Twenty three healthy adults (18-29 years of age; eight women) were assigned to either a high fatigue protocol (HF: four sets of 10 repetitions with 30 seconds rest between sets) to maximise metabolic stress or a low fatigue protocol (LF: 40 repetitions with 30 seconds between each repetition) to minimise changes. Subjects lifted on average 73% of their 1 repetition maximum through the full range of knee extension with both legs, three times a week. Quadriceps isometric strength of each leg was measured at a knee joint angle of 1.57 rad (90 degrees ), and a Cybex 340 isokinetic dynamometer was used to measure the angle-torque and torque-velocity relations of the non-dominant leg.
At the mid-point of the training, the HF group had 50% greater gains in isometric strength, although this was not significant (4.5 weeks: HF, 13.3 (4.4)%; LF, 8.9 (3.6)%). This rate of increase was not sustained by the HF group, and after nine weeks of training all the strength measurements showed similar improvements for both groups (isometric strength: HF, 18.2 (3.9)%; LF, 14.5 (4.0)%). The strength gains were limited to the longer muscle lengths despite training over the full range of movement.
Fatigue and metabolite accumulation do not appear to be critical stimuli for strength gain, and resistance training can be effective without the severe discomfort and acute physical effort associated with fatiguing contractions.
The measurement of human muscle size is essential when assessing the effects of training, disuse and ageing. The considered 'gold standard' for cross-sectional area measurements of muscle size is magnetic resonance imaging (MRI). However, MRI is costly and often inaccessible. The aim of the present study was to test the reproducibility and validity of a more accessible alternative method using ultrasonography (ULT). We examined the cross-sectional areas in the vastus lateralis muscle of six individuals. Axial-plane ULT scans were taken at given levels along the entire muscle length. The ULT scanning was repeated on different days (reliability) and validated against MRI-based measurements. Mean intraclass correlation coefficients were 0.998 for the reliability of ULT and 0.999 for the validity of ULT against MRI. The coefficient of variation values for cross-sectional area measurements assessed by six different experimenters were 2.1% and 0.8% for images obtained with ULT and MRI, respectively. The ULT method is a valid and reliable alternative tool for assessing cross-sectional areas of large individual human muscles. The present findings justify the application of the ULT method for the detection of changes throughout large muscles in response to training, disuse or as a consequence of sarcopenia.
Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the "strength-endurance continuum". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, prolonged contractions, with significant increases after training in aerobic power and time to exhaustion. Thus, low and intermediate RM training appears to induce similar muscular adaptations, at least after short-term training in previously untrained subjects. Overall, however, these data demonstrate that both physical performance and the associated physiological adaptations are linked to the intensity and number of repetitions performed, and thus lend support to the "strength-endurance continuum".