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Dissociated time course between peak torque and total work recovery following bench press training in resistance trained men
... Acute RE can lead to transient fatigue (reflected in temporarily reduced maximal strength capabilities) (33,51). At least 3 lines of evidence indicate that beginning each set of RE in a fatigued state can, over time, diminish gains in strength. ...
... Resistance exercise does not enhance strength; rather, recovery from and subsequent adaptation to RE enhances strength. In other words, RE causes fatigue and muscle damage, which actually can impair strength in the short term (33,51). However, if sufficient recovery is provided, then "supercompensation" (incremental improvements in performance beyond previous capabilities) occurs as an adaptive response (97). ...
... Another potential supplementary activity is motor imagery. Traditional RE causes fatigue and muscle damage (33), which potentially limits the dose of training that can be tolerated (because of the need to recover and avoid overtraining). Thus, traditional RE could conceivably be supplemented with kinesthetic motor imagery training to further enhance strength gains without exacerbating fatigue and muscle damage. ...
Traditional heavy resistance exercise (RE) training increases maximal strength, a valuable adaptation in many situations. That stated, some populations seek new opportunities for pushing the upper limits of strength gains (e.g., athletes and military personnel). Alternatively, other populations strive to increase or maintain strength but cannot perform heavy RE (e.g., during at-home exercise, during deployment, or after injury or illness). Therefore, the purpose of this narrative review is to (a) identify the known stimuli that trigger gains in strength; (b) identify the known factors that mediate the long-term effectiveness of these stimuli; (c) discuss (and in some cases, speculate on) potential opportunities for maximizing strength gains beyond current limits (d) discuss practical applications for increasing or maintaining strength when traditional heavy RE cannot be performed. First, by conceptually deconstructing traditional heavy RE, we identify that strength gains are stimulated through a sequence of events, namely: giving maximal mental effort, leading to maximal neural activation of muscle to produce forceful contractions, involving lifting and lowering movements, training through a full range of motion, and (potentially) inducing muscular metabolic stress. Second, we identify factors that mediate the long-term effectiveness of these RE stimuli, namely: optimizing the dose of RE within a session, beginning each set of RE in a minimally fatigued state, optimizing recovery between training sessions, and (potentially) periodizing the training stimulus over time. Equipped with these insights, we identify potential opportunities for further maximizing strength gains. Finally, we identify opportunities for increasing or maintaining strength when traditional heavy RE cannot be performed. © 2023 NSCA National Strength and Conditioning Association. All rights reserved.
... [3][4][5], the current body of literature has ambiguity regarding the definition of failure itself. Specifically, the term failure has referred to the inability to complete the concentric phase despite maximal effort (momentary failure) [12], an individual terminating a set without actually failing (volitional failure) [33,34], and not completing a set at a predetermined movement tempo [36], among other definitions. ...
... In this hypothetical, it cannot be known if the results would have been the same because fatigue may have been lower and inter-session recovery time faster with volitional and not momentary failure. Further, Lacerda et al. [19] reported a higher session rating of perceived exertion across an entire 14-week training study in a failure training group using a similar definition as Santanielo Ferreira et al. [36] observed that upper body volume performance did not fully recover within 96 h following eight sets of bench press to failure. Ferreira et al. defined failure as not performing a bench press repetition at the specified tempo (1-2 s concentric and 2-3 s eccentric). ...
... In these studies, the load used was intended to produce failure on sets after a predetermined number of repetitions; however, it is not known how often subjects reached momentary failure in these studies. The greater volume in Ferreira et al. [36] (i.e., 8 sets) vs lower volume in Morán-Navarro et al. [24] and Pareja-Blanco et al. [25] (i.e., 6 combined sets of squat and bench press) may account for the longer time course of recovery in Ferreira et al. Ultimately, many factors (e.g., failure definitions, total volume, assessed recovery metrics, individual rates of recovery, training status) may account for the varying time courses of recovery; however, the differing definitions of failure may be partly responsible for the between-study recovery discrepancy. ...
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.
... Resistance training may result in both significant muscle damage and fatigue in untrained (Newham et al. 1983;Nosaka and Newton 2002;Howatson et al. 2007) and trained individuals (Raeder et al. 2016; Barnes et al. 2017;Ferreira et al. 2017). Consequently, the magnitude and duration of the subsequent recovery then regulates both training volume and frequency (Bird et al. 2005). ...
... Importantly, the magnitude of muscle damage may vary between different exercises (Soares et al. 2015). Specifically, the back squat, bench press, and deadlift are commonly used as primary training exercises by athletes (Coutts et al. 2007;International Powerlifting Federation 2015;Pritchard et al. 2016) and are frequently used in research with recreational lifters (Raeder et al. 2016; Barnes et al. 2017;Ferreira et al. 2017). Recently, Ferreira et al. (2017) observed that it took up to 96 h for both maximal work capacity to recover and delayed onset muscle soreness (DOMS) to subside following 8 sets of bench press to failure in trained lifters (Ferreira et al. 2017). ...
... Specifically, the back squat, bench press, and deadlift are commonly used as primary training exercises by athletes (Coutts et al. 2007;International Powerlifting Federation 2015;Pritchard et al. 2016) and are frequently used in research with recreational lifters (Raeder et al. 2016; Barnes et al. 2017;Ferreira et al. 2017). Recently, Ferreira et al. (2017) observed that it took up to 96 h for both maximal work capacity to recover and delayed onset muscle soreness (DOMS) to subside following 8 sets of bench press to failure in trained lifters (Ferreira et al. 2017). In addition, Morán-Navarro (2017) demonstrated that 3 sets to failure at 75% of 1-repetition maximum (1RM) on the back squat hindered lifting velocity and increased circulating creatine kinase (CK) for up to 72 h (Morán-Navarro et al. 2017). ...
This study examined the time course of recovery following resistance exercise sessions in the back squat, bench press, and deadlift. Twelve well-trained males (age: 24.5±3.8yrs, body mass: 84.01±15.44kg, training age: 7.1±4.2yrs) performed 4 sets to failure at 80% of a one-repetition maximum (1RM) on the squat, bench press, and deadlift in successive weeks. The bench press was always performed in week-2 with the squat and deadlift order counterbalanced between weeks 1 and 3. Indirect muscle damage and performance fatigue was assessed immediately prior to, post-exercise, and 24, 48, 72, and 96hrs post-exercise. Outcome measures included: limb swelling, joint range of motion, delayed onset muscle soreness, average concentric velocity (ACV) at 70% of 1RM, creatine kinase, lactate dehydrogenase, and cell-free DNA (cfDNA). Most measures demonstrated a main time effect (p<0.05) within conditions, however, no between condition (p>0.05) differences existed. ACV decreased in the squat condition for up to 72 hours (p=0.02, -8.61%) and in the bench press (p<0.01, -26.69%) immediately post-exercise, but did not decline during the deadlift condition (p>0.05). There was a main time effect for increased cfDNA in the squat (p<0.01) and bench press (p<0.05), but not the deadlift (p=0.153). Further, immediately post-exercise increases in cfDNA were directly related (p<0.05) to changes in ACV in all three conditions. These results suggest that the deadlift does not result in greater muscle damage and recovery time than the squat and bench press following volume-type training in well-trained men. Further, acute changes in cfDNA may predict performance during the recovery period.
... Different from muscle swelling, CMJ, or MVIT, WC did not return to pre-exercise levels even 72 h after the exercise protocol in PLA, while subjects exposed HMB-FA acute supplementation have totally restored their WC at 24 h after the exercise protocol. Interestingly, previous studies have reported the dissociation between the time-course of peak torque and WC recovery in trained subjects (Ferreira et al. 2017). Such phenomenon occurs because muscle strength and muscle fatigability have different related mechanisms. ...
... Such phenomenon occurs because muscle strength and muscle fatigability have different related mechanisms. During a high-intensity exercise, a complex sequence of events occurs, including sarcomere disruption, increased inflammatory response, depletion of muscle glycogen, decreased insulin sensitivity, and reduction of glucose transporters' mobilization (Asp et al. 1996;Proske and Morgan 2001;Tee et al. 2007;Ferreira et al. 2017). This cascade of events could impair metabolic function and decrease WC for several days after a single high-intensity exercise bout (Peake et al. 2005;Hughes et al. 2013). ...
... Moreover, the acute supplementation of HMB-FA seems to improve protein synthesis and inhibit protein breakdown, accelerating the regeneration of sarcomere membrane (Wilkinson et al. 2013;Wilson et al. 2013b). Such pathways may contribute to restore muscle glycogen and recover WC after a high-intensity exercise, suggesting that a single-dose supplementation of HMB-FA could be taken to improve recovery by athletes enrolled in high-intensity activities with duration between 20 and 120 s (Ferreira et al. 2017). ...
The purpose of this study was to investigate the effects of a single-dose of β-hydroxy-β-methylbutyrate free acid (HMB-FA) supplementation on muscle recovery after a high-intensity exercise bout. Twenty-three trained young males were randomly assigned to receive either a single-dose supplementation of 3g of HMB-FA (n = 12; age 22.8 ± 3.0 years) or placebo (PLA; n = 11; age 22.9 ± 3.1 years). A muscle damage protocol was applied 60 minutes after supplementation, and consisted of seven sets of 20 drop jumps from a 60-cm box with 2-min rest intervals between sets. Muscle swelling, countermovement jump (CMJ), maximal voluntary isometric torque (MVIT) and work capacity (WC) were measured before, immediately after, 24, 48 and 72 hours after the exercise protocol. Muscle swelling, CMJ and MVIT changed similarly in both groups after the exercise protocol (p < 0.001), but returned to pre-exercise levels after 24 hours in both groups. WC decreased similarly in both groups after the exercise protocol (p < 0.01). For HMB-FA, WC returned to pre-exercise level 24 hours after exercise protocol. However, on PLA, WC did not return to pre-exercise level even 72 hours after the exercise protocol. In summary, a single-dose of HMB-FA supplementation improved WC recovery after a high-intensity exercise bout. However, HMB-FA did not affect the time-course of muscle swelling, MVIT and CMJ recovery.
... delayed-onset muscle soreness (DOMS), perception of recovery) (Kennedy and Drake 2018, Belcher et al 2019, Nunes et al 2019, Basham et al 2020, Mavropalias et al 2020. These parameters have shown dissociated time courses for recovery after resistance exercise, mainly muscle performance parameters when compared to psychometric parameters (Ferreira et al 2017, Belcher et al 2019. For instance, a recent study showed that subjective physical fitness recovered 72 h following a training session, while muscle strength returned to baseline values at 96 h post-exercise, and total work did not return to baseline values throughout the entire 96 h post-exercise period (Ferreira et al 2017). ...
... These parameters have shown dissociated time courses for recovery after resistance exercise, mainly muscle performance parameters when compared to psychometric parameters (Ferreira et al 2017, Belcher et al 2019. For instance, a recent study showed that subjective physical fitness recovered 72 h following a training session, while muscle strength returned to baseline values at 96 h post-exercise, and total work did not return to baseline values throughout the entire 96 h post-exercise period (Ferreira et al 2017). ...
The measurement of skin temperature using infrared thermography has gained a lot of attention in sport and science since it might be related to the recovery process following high intensity, potentially damaging exercise. This study investigated the time course of the skin temperature response and the muscle recovery status following a resistance training session involving leg press exercise. Fourteen young male college students (19.9 ± 1.7 years, 176 ± 6 cm, 66.1 ± 7.6 kg, 21.1 ± 1.8 kg.m-2) performed one session involving 10 sets, of 10 repetition maximum each (RM), of unilateral leg press 45° exercise, performed to momentary muscle failure, with 2 min rest between sets. Perceived recovery, mean and maximum thigh skin temperatures, thigh muscle thickness, maximal isometric strength, muscle soreness, and horizontal jump performance were measured pre, 24, 48, and 72 h following exercise. The exercise protocol resulted in significant reduction in isometric strength, horizontal jump performance, and perceived recovery (p< 0.05). There was also a significant (p<0.05) increase in muscle thickness and muscle soreness. With exception of jump performance, that recovered at 48 (p> 0.05), recovery parameters did not recover up to 72 h post-exercise (p> 0.05). Surprisingly, skin temperatures were not altered throughout the entire 72-h post-exercise period (p> 0.05). No significant positive correlation was found between skin temperatures and muscle thickness. Additionally, only one out of 16 correlation coefficients showed significant (r= -0.56, p= 0.036) inverse association between skin temperature and isometric strength. In conclusion, thigh skin temperature remains unaffected up to 72 h following a leg press exercise, and the time course response of thigh skin temperature was not associated with recovery status.
... Next, 2 sets with maximal effort and 1 repetition each were performed, followed by a passive gravity correction measurement. 2 minutes of rest was provided between trials and test positions (11). In accordance with previous research (11) and to resemble average bench press speed, movement speed was set to 60°·s 21 . ...
... 2 minutes of rest was provided between trials and test positions (11). In accordance with previous research (11) and to resemble average bench press speed, movement speed was set to 60°·s 21 . ...
Mausehund, L, Werkhausen, A, Bartsch, J, and Krosshaug, T. Understanding bench press biomechanics-The necessity of measuring lateral barbell forces. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to advance the expertise of the bench press exercise by complementing electromyographic (EMG) with net joint moment (NJM) and strength normalized NJM (nNJM) measurements, thus establishing the magnitude of the elbow and shoulder muscular loads and efforts. Normalized NJMs were determined as the ratio of the bench press NJMs to the maximum NJMs produced during maximum voluntary isokinetic contractions. Furthermore, we wanted to assess how changes in grip width and elbow positioning affected elbow and shoulder NJMs and nNJMs, and muscle activity of the primary movers. Thirty-five strength-trained adults performed a 6-8 repetition maximum set of each bench press variation, while elbow and shoulder NJMs and EMG activity of 7 upper extremity muscles were recorded. The results show that all bench press variations achieved high elbow and shoulder muscular efforts. A decrease in grip width induced larger elbow NJMs, and larger EMG activity of the lateral head of the triceps brachii, anterior deltoid, and clavicular head of the pectoralis major (p ≤ 0.05). An increase in grip width elicited larger shoulder NJMs and nNJMs, and larger EMG activity of the abdominal head of the pectoralis major (p ≤ 0.05). In conclusion, all bench press variations may stimulate strength gains and hypertrophy of the elbow extensors and shoulder flexors and horizontal adductors. However, greater adaptations of the elbow extensors and shoulder flexors may be expected when selecting narrower grip widths, whereas wider grip widths may induce greater adaptations of the shoulder horizontal adductors.
... This effect may be considered as a consequence of deficits in sensorial integration or unbalanced information, responsible for internal model calibration (Wolpert et al., 2011). Muscle recovery process following muscle damage may suggest an incompatibility between information provided by proprioception and vision, as muscle recovery occurs gradually after EIMD with a dissociated time-course recovery of muscle damage variables (Ferreira et al., 2017). The initial process of muscle recovery is marked by DOMS cessation and by the increased perception of recovery, followed by an improvement in muscle performance ( Table 2). ...
... Muscle damage caused by the current resistance exercise protocol is in accordance with previous studies that have evaluated muscle recovery after resistance exercise in untrained men (Ferreira et al., 2017;Nosaka, Newton, & Sacco, 2002;Zaheer, Moiz, Shareef, & Hussain, 2014) and may be considered severe (Paulsen et al., 2012). Other muscle damage protocols are considered less severe (Clarkson & Hubal, 2002;Paulsen et al., 2012) and, therefore, they may have a different effect on learning. ...
Motor skill learning is a fundamental aspect of human behavior based on the calibration of internal models via sensory information such as proprioception. Some conditions, as exercise-induced muscle damage (EIMD), disrupt proprioceptive information, and may cause learning impairment. Such possible relation between EIMD and motor skill learning has not yet been investigated and it is the aim of this study. For this purpose, thirty male university students (19.3 ± 1.8 years) were equally assigned to two groups: EIMD and CON group. The EIMD group received a treatment to induce muscle damage consisting of a weight lifting protocol directed to the agonist muscles related to the task prior to the pretest and to the learning sessions. EIMD was verified and compared between groups and along the process (0-168 h) by means of the degree of delayed onset muscle soreness (DOMS), perceived total quality recovery and maximal isometric strength (MIS). To investigate motor skill learning, both groups practiced a dart throwing task for four sessions with 150 trials in each session. Recovery status and DOMS were recovered at 96 h in the EIMD group, and MIS was not recovered throughout 168 h. In contrast, muscle damage parameters were not altered across 168 h in the CON group. Accuracy and consistency were compared within and between groups in a pretest posttest design. The EIMD group showed less accurate and consistent results on the long term (delayed posttest). Results confirmed our hypothesis that EIMD, a common condition in sports and in rehab practices, may hinder motor skill learning, possibly due to neurological aspects such as proprioceptive information, its relation to central nervous system reorganization and internal model consolidation.
... Altri test per monitorare il recupero muscolare sono le misurazioni isocineti che della forza, realizzate att raverso l'impiego di dinamometri lineari (4, 5) o angolari (10,14). Diminuzioni signifi cati ve del picco di forza isocineti ca sono stati riscontrati dopo AF ad alto volume, sia in soggetti allenati (5) che nei neofi ti (7), mentre è stato rilevato un tempo di recupero più lungo per il momento torcente in individui non allenati rispett o a quelli più esperti (24). ...
La lett eratura scienti fi ca si è concentrata molto sul recupero post al-lenamento e la presente revisione intende aff rontare questo tema, in relazione all'allenamento della forza. Verrà dapprima tratt ato il tema del danno muscolare con riferimento alla contrazione eccentrica, con-centrica ed isometrica. Notevoli stress metabolici e meccanici infatti , possono essere generati da esercizi concentrici ed isometrici e non solamente da contrazioni eccentriche, alle quali di solito vengono as-sociati. La combinazione dei diversi ti pi di contrazione muscolare po-trebbe poi amplifi care il danno muscolare ma, se ben gesti ta, anche otti mizzare il processo di adatt amento. Un altro tema di recente espansione è quello relati vo a come le diff e-renze di sesso possano infl uenzare le fasi di recupero post allenamen-to di forza. Diversi studi hanno infatti riportato tempi di recupero più brevi nelle donne rispett o agli uomini. Le fasi di recupero risultano infl uenzate dall'assett o endocrino e dalle diff erenze fra i sessi nella presenza delle varie ti pologie di fi bre muscolari. Dunque, l'allenamen-to di forza deve tener presente queste diff erenze fra i sessi in modo da gesti re carichi e recuperi al fi ne di otti mizzare il processo di adat-tamento. La lett eratura ha inoltre studiato il recupero muscolare mediante il monitoraggio della performance in queste fasi, uti lizzando diversi test da campo e da laboratorio. Alcune valutazioni da campo, come il countermovement jump ed il bench press throw, si sono rivelate par-ti colarmente sensibili nel monitoraggio delle fasi di recupero mentre altri test di ti po isometrico si sono dimostrati meno adatti a identi fi care situazioni di aff ati camento persistente dopo allenamento di forza.
... Interestingly, the state of recovery was perceived as incomplete both 24 and 48 h after the power-oriented session although performance was back to baseline, or even above (squat peak power and MJ). Recent studies support a partly dissociated time course between objective and subjective recovery status-for both upper and lower body muscles-indicating a slower recovery when assessed subjectively (Zourdos et al., 2016;Ferreira et al., 2017a;Ferreira et al., 2017b;Marshall, Cross & Haynes, 2018). In summary, this advocates for caution in interpreting subjective and objective measures of recovery. ...
The present randomized cross-over controlled study aimed to compare the rate of recovery from a strength-oriented exercise session vs. a power-oriented session with equal work. Sixteen strength-trained individuals conducted one strength-oriented session (five repetitions maximum (RM)) and one power-oriented session (50% of 5RM) in randomized order. Squat jump (SJ), countermovement jump (CMJ), 20-m sprint, and squat and bench press peak power and estimated 1RMs were combined with measures of rate of perceived exertion (RPE) and perceived recovery status (PRS), before, immediately after and 24 and 48 h after exercise. Both sessions induced trivial to moderate performance decrements in all variables. Small reductions in CMJ height were observed immediately after both the strength-oriented session (7 ± 6%) and power-oriented session (5 ± 5%). Between 24 and 48 h after both sessions CMJ and SJ heights and 20 m sprint were back to baseline. However, in contrast to the power-oriented session, recovery was not complete 48 h after the strength-oriented session, as indicated by greater impairments in CMJ eccentric and concentric peak forces, SJ rate of force development (RFD) and squat peak power. In agreement with the objective performance measurements, RPE and PRS ratings demonstrated that the strength-oriented session was experienced more strenuous than the power-oriented session. However, these subjective measurements agreed poorly with performance measurements at the individual level. In conclusion, we observed a larger degree of neuromuscular impairment and longer recovery times after a strength-oriented session than after a power-oriented session with equal total work, measured by both objective and subjective assessments. Nonetheless, most differences were small or trivial after either session. It appears necessary to combine several tests and within-test analyses (e.g., CMJ height, power and force) to reveal such differences. Objective and subjective assessments of fatigue and recovery cannot be used interchangeably; rather they should be combined to give a meaningful status for an individual in the days after a resistance exercise session. Subjects Anatomy and Physiology, Kinesiology
... The powerlifts are also widely used as exercises to increase and assess strength and performance by many athletes as well as in research with recreational lifters (e.g. Rugby and American Football players) [11][12][13][14]. Aside from athletes, active individuals who seek to increase their overall body strength often utilise the three powerlifts as they are multi-joint exercises that are effective and efficient at increasing whole-body strength due to utilising multiple muscle groups at once [15][16][17]. ...
Increases in muscular strength may increase sports performance, reduce injury risk, are associated with a plethora of health markers, as well as exerting positive psychological effects. Due to their efficiency and effectiveness in increasing total body muscular strength, multi-joint exercises like the powerlifts, i.e.: the squat (SQ), bench-press (BP) and deadlift (DL), are widely used by active individuals as well as athletes in the pursuit of increasing strength. To date, the concept of a minimum dose, i.e. “what is the minimum one needs to do to increase 1-repetition maximum (1RM) strength?” has not been directly examined in the literature, especially in the context of the powerlifts. This review aims to explore the current available evidence around the minimum effective training dose required to increase 1RM strength in trained individuals in an attempt to enhance the practical guidelines around resistance-training as well as provide active individuals, athletes and coaches with more flexibility when designing a training protocol.
One reviewer independently conducted the search in a PRISMA systematic approach using PubMed, SportDiscus and Google Scholar databases. The databases were searched with the following search terms/phrases and Boolean operators: “training volume” AND “powerlifting” OR “1RM strength” OR “powerlifters”, “low volume” AND “powerlifting” OR “powerlifting” OR “1RM strength”, “high vs low volume” AND “powerlifting” OR “1RM strength”, “minimum effective training dose 1RM”. Meta-analyses were performed to estimate the change in 1RM strength for the lowest dose group in the included studies.
From the initial 2629 studies, 6 studies met our inclusion criteria. All identified studies showed that a single set performed minimum 1 time and maximum 3 times per week was sufficient to induce significant 1RM strength gains. Meta-analysis of 5 studies showed an estimated increase for overall 1RM of 12.09 kg [95% CIs 8.16 kg–16.03 kg], an increase of 17.48 kg [95% CIs 8.51 kg–26.46 kg] for the SQ, and 8.25 kg [95% CIs 0.68 kg–15.83 kg] for the BP. All of the included studies contained details on most of the variables comprising “training dose”, such as: weekly and per session sets and repetitions as well as intensity of effort. Specific information regarding load (%1RM) was not provided by all studies.
The results of the present systematic review suggest that performing a single set of 6–12 repetitions with loads ranging from approximately 70–85% 1RM 2–3 times per week with high intensity of effort (reaching volitional or momentary failure) for 8–12 weeks can produce suboptimal, yet significant increases in SQ and BP 1RM strength in resistance-trained men. However, because of the lack of research, it is less clear as to whether these improvements may also be achievable in DL 1RM strength or in trained women and highly trained strength athletes.
This systematic review was registered with PROSPERO (CRD42018108911).
... Falls in work capacity occurs due to reduced glycogen content and impaired glucose transport in response to insulin. 23 Cancer survivors may show an increased systemic acidity due to Warburg effect and overproduction of hydrogen ions, 24 which affect glycogen's production and content. Otherwise, insulin sensibility could also affect glucose transportation and work capacity. ...
Introduction: Prostate cancer is the most prevalent neoplastic disease in men. After diagnosis, different treatment regimens are proposed based on the stage of the cancer. These treatments affect physical and muscle function, quality of life, and prognosis differently. Objectives: To assess fatigue, muscle strength, muscle thickness, and muscle quality in prostate cancer survivors undergoing androgen deprivation therapy (ADT). Methods: Ten ADT patients, eight non-ADT patients and 18 healthy control subjects were enrolled in this study. Perceived fatigue was assessed through the 20-item Multidimensional Fatigue Inventory. Muscle thickness and quality (e.g., echo intensity) were assessed through B-mode ultrasound. Muscle strength and work capacity were assessed using an isokinetic dynamometer. The groups were compared with one-way ANOVA and Bonferroni adjustment. Results: Muscle thickness, peak torque, and work capacity were lower in ADT than in the control group (CON) (p = 0.021; p = 0.005; p <0.001, respectively). ADT showed greater echo intensity than CON (p = 0.005) and N-ADT (p = 0.046). There were no differences between N-ADT and CON in terms of muscle thickness, peak torque, work capacity, and echo intensity (p >0.05). General fatigue was greater in both ADT (p = 0.030) and N-ADT (p = 0.047) compared to CON. Physical fatigue was greater in ADT than CON (p = 0.006). Conclusion: ADT patients showed lower levels of muscle function and greater levels of perceived fatigue than healthy control subjects. It appears that muscle function remains lower in ADT patients, even several years after treatment initiation, although this does not apply to non-ADT patients. Level of evidence II; Diagnostic Studies-Investigating a Diagnostic Test.
... The suggestion that the addition of SJ exercises might be necessary to provide optimal stimulation and thus adaptations, especially to the arm muscles, is partially supported by the current literature. In this regard, acute (Ferreira et al., 2017;Soares et al., 2015) and chronic (Ogasawara, Thiebaud, Loenneke, Loftin, & Abe, 2012) studies suggest that arm muscles are not adequately stimulated during MJ exercises. Taken together, these suggest that MJ exercise might promote a suboptimal stimulus for some muscles and, therefore, the addition of SJ exercises might improve muscle adaptations . ...
The purpose of the present study was to compare the changes in anthropometric measures and muscle performance in users and non-users of androgenic anabolic steroids (AAS) performing resistance training (RT) programmes involving only multiple joint (MJ) exercises or a combination of MJ and single joint (SJ) exercises. Thirty recreational bodybuilders were divided into 4 groups: non-AAS users performing only MJ exercises (MJ), non-AAS users performing MJ + SJ (MJ + SJ), AAS users performing only MJ exercises (AAS − MJ) and AAS users performing MJ + SJ exercises (AAS − MJ + SJ). Before and after 8 weeks of training, the participants were tested for 10 repetition maximum (10RM) in different RT exercises. Flexed arm circumference (FAC), biceps and triceps skinfolds were measured. No interactions were found between time and the performance of SJ exercise in any variable (p > .05). However, there was a significant interaction between AAS use and time (p < .001), such that AAS users showed greater 10RM gains in all exercises, skinfold decreases and increases in FAC than non-users. In conclusion, our study shows that the addition of SJ exercises to MJ exercises brings no additional benefit in terms of muscle performance and anthropometric changes in trained men, either if they were using AAS or not. These results suggest that trained men can save time not including SJ in their routines and still achieve optimal results. Moreover, our results show that AAS use is associated with greater increases in muscle strength and FAC and greater reductions in biceps and triceps skinfold thickness.
... First, the additional effect of β-alanine supplementation on intracellular buffer capacity (i.e., reducing acidosis) may be insufficient to overcome the negative impact of RE on muscle function during the recovery period. Highintensity RE is naturally associated with pronounced microinjury (as indicated by the increase in CK levels) (da Silva et al. 2017;Waldron et al. 2017;Pareja-Blanco et al. 2018) and delayed-onset muscle soreness (Flores et al. 2011;da Silva et al. 2017;Waldron et al. 2017), resulting in a marked decline in muscle function (e.g., peak torque and isometric strength) (Flores et al. 2011;Ferreira et al. 2017;Waldron et al. 2017). This impairment on muscle function may be exacerbated when exercise is performed until muscle failure (Morán-Navarro et al. 2017;Pareja-Blanco et al. 2018), and generally requires a period of 48-72 h for complete recovery (ACSM 2009). ...
β-alanine supplementation has been shown to increase muscle carnosine levels and exercise performance. However, its effects on muscle recovery from resistance exercise (RE) remains unknown. The purpose of this study was to investigate the effects of β-alanine supplementation on muscle function during recovery from a single session of high-intensity RE. Twenty-four untrained young adults (22.1 ± 4.6 years old) were assigned to 1 of 2 groups (N = 12 per group): a placebo-supplement group (4.8 g/day) or an β-alanine-supplement group (4.8 g/day). The groups completed a single session of high-intensity RE after 28 days of supplementation and were then evaluated for muscle function on the 3 subsequent days (at 24, 48, and 72 h postexercise) to assess the time course of muscle recovery. The following indicators of muscle recovery were assessed: number of repetitions until failure, rating of perceived exertion, muscle soreness, and blood levels of creatine kinase (CK). Number of repetitions until failure increased from 24 h to 48 h and 72 h of recovery (time, P < 0.01), with no difference between groups. There was a significant increase in rating of perceived exertion among the sets during the RE session (time, P < 0.01), with no difference between the groups. No difference was observed over time and between groups in rating of perceived exertion in the functional tests during recovery period. Blood CK levels and muscle soreness increased at 24 h postexercise and then progressively declined at 48 and 72 h postexercise, respectively (time, P < 0.05), with no difference between groups. In conclusion, our data indicate that β-alanine supplementation does not improve muscle recovery following a high-intensity RE session in untrained young adults.
... A similar trend was observed for MVC performance, while the inverse was noted for perceived soreness scores, decreased (MVC) or increased (soreness) values at 24 hours after exercise, which had begun to return to baseline at 48 hours. These results confer with previous findings (15,24), and demonstrate the potentially fatiguing influence of previous training on subsequent sessions. Despite following similar trends though, the lack of any significant relationships between the change in 1RM and change in MVC or perceived soreness highlights the importance of developing more advanced fatigue monitoring strategies. ...
The purpose of this study was to investigate using load-velocity relationships to quantify fluctuations in maximal strength (1-repetition maximum; 1RM) which occur as a result of training-induced fatigue. The nineteen well-trained males (age: 24.3±2.9 years, height: 180.1±5.9 cm, body mass: 84.2±10.5 kg, squat 1RM: 151.1 ± 25.7 kg) who were recruited for this study attended five sessions. After baseline strength testing, individual load-velocity relationships were established using mean concentric velocity during visits 2, 4 and 5, with visit 3 consisting of a bout of fatiguing exercise (5 sets of squats performed to muscular failure with 70% 1RM). Predicted 1RM values were calculated using the minimal velocity threshold (1RMMVT), load at zero velocity (1RMLD0) and force-velocity (1RMFV) methods. Measured 1RM, maximal voluntary contractions, and perceived muscle soreness were used to examine the effects of fatigue in relation to the predicted 1RM scores. The 1RMMVT and 1RMLD0 demonstrated a very strong and strong correlation with measured 1RM during each of the sessions (r = 0.90-0.96 and r = 0.77-0.84, respectively), while no strong significant correlations were observed for the 1RMFV. Further analysis using Bland-Altman plots demonstrated substantial inter-individual variation associated with each method. These results suggest that load-velocity based 1RM predictions are not accurate enough to be used for daily training load prescription, as has been previously suggested. Nevertheless, these predictions are practical to implement during an individual’s warm- up, and may be useful to indicate general fluctuations in performance potential, particularly if used in conjunction with other common monitoring methods.
... Among the most popular methods we call attention to elastic resistance and dumbbell workouts during shoulder exercises given their practicality and versatility. Dumbbell workouts during shoulder exercises is strongly recommended as parts of shoulder rehabilitation programs despite the limited evidence available to guide physiotherapists in deciding the type of resistance or the ideal exercise (Ferreira et al., 2017). In line with some previous conducts, proprioceptive neuromuscular facilitation (PNF) represents an additional method to promote shoulder rehabilitation by means of maximum biomechanical stretching and therefore, increased functional movements by muscular and proprioceptive stimulation (Witt et al., 2011). ...
The shoulder is susceptible to disturbances caused by microtraumas due to direct contact of the surrounding skeletal structures or failure of the soft parts of the rotator cuff and other muscles inserted into the glenohumeral joint. The purpose of the study was to compare the electromyographic signal in the stabilizing muscles of the shoulder during the diagonal elevation exercise as recommended by the proprioceptive neuromuscular facilitation (PNF) method and dumbbell exercise. This study is classified as Quase-experiment. Subjects were instructed to perform diagonal standard exercises and the electromyographic signal was detected from pectoralis muscles, middle and upper trapezius of dominant limb in each subject. We observed greater muscular recruitment when the PNF method was adopted in comparison with the dumbbell workouts for the trapezius upper and middle fiber muscles and for the major pectoralis (267,30 μv/181,02 μv; 235,76 μv/;164,47 μv; 299,87 μv/148,69 μv; P<0.001). The PNF method promotes a greater recruitment of the shoulder dynamic stabilizing muscles during diagonal elevation exercises. Being so, such kinesiotherapeutic technique may be effectively used in the prevention, treatment and rehabilitation of shoulder disorders.
There have been a multitude of reviews written on exercise-induced muscle damage (EIMD) and recovery. EIMD is a complex area of study as there are a host of factors such as sex, age, nutrition, fitness level, genetics and familiarity with exercise task, which influence the magnitude of performance decrement and the time course of recovery following EIMD. In addition, many reviews on recovery from exercise have ranged from the impact of nutritional strategies and recovery modalities, to complex mechanistic examination of various immune and endocrine signaling molecules. No one review can adequately address this broad array of study. Thus, in this present review, we aim to examine EIMD emanating from both endurance exercise and resistance exercise training in recreational and competitive athletes and shed light on nutritional strategies that can enhance and accelerate recovery following EIMD. In addition, the evaluation of EIMD and recovery from exercise is often complicated and conclusions often depend of the specific mode of assessment. As such, the focus of this review is also directed at the available techniques used to assess EIMD.
This study determined the time-course of recovery after resistance training (RT) sessions and the association between changes in performance with changes in biomechanical, physiological and perceptual parameters. After a 4-week familiarization period, 14 resistance-trained males performed 3 experimental conditions, each one including 2 sessions with a recovery interval of 24h, 48h or 72h, in a randomized order. RT sessions consisted of 5 sets of 8-10RM on squat and leg press exercises. The resistance was equal for the 2 sessions of each condition and repetitions were performed until concentric failure. Volume load (VL) and first set volume load (FSVL) were compared between sessions. Tests before each session included countermovement jump (CMJ), maximal voluntary isometric contraction (MVIC), creatine kinase (CK) and delayed onset muscle soreness (DOMS). (2x3) ANOVA with effect sizes (ES) assessed the time-course of recovery and Kendall test the correlation between variables (α=0.05). Significant interaction was observed for all variables, except for CK, where a condition main effect occurred. Comparisons between post and pre-intervals showed VL (p=0.011;ES=-0.90) decreased for 24h condition, while FSVL remained decreased for 48h (p=0.031;ES=-0.63) and DOMS increased (p=0.001;ES=3.52). CMJ (p=0.025;ES=0.25) and MVIC (p=0.031;ES=0.14) performance increased at 72h. FSVL (r=0.424), CMJ (r=0.439), MVIC (r=0.389) and DOMS (r=-0.327) were significantly correlated with VL (p<0.05). Time-course of VL showed the necessity of at least 48h for the reestablishment of performance, though better perceptual responses were evident at 72h. Thus, both recovery intervals may be beneficial after lower-limbs RT until concentric failure, though chronic effects still need to be investigated.
Introduction: The purpose of the present study was to compare the effects of different volumes of resistance training (RT) on muscle performance and hypertrophy in trained women. Methods: The study included 40 volunteers that performed RT for 24 weeks divided in to groups that performed five (G5), 10 (G10), 15 (G15) and 20 (G20) sets per muscle group per session. Ten repetition maximum (10RM) tests were performed for the bench press, lat pull down, 45º leg press, and stiff legged deadlift. Muscle thickness (MT) was measured using ultrasound at biceps brachii, triceps brachii, pectoralis major, quadriceps femoris, and gluteus maximus. Results: All groups significantly increased all MT measures and 10RM tests after 24 weeks of RT (p<0.05). Between group comparisons revealed no differences in any 10RM test between G5 and G10 (p>0.05). G5 and G10 showed significantly greater 10RM increases than G15 for lat pulldown, leg press and stiff legged deadlift. 10RM changes for G20 were lower than all other groups for all exercises (p<0.05). G5 and G10 showed significantly greater MT increases than G15 and G20 in all sites (p<0.05). MT increased more in G15 than G20 in all sites (p<0.05). G5 increases were
higher than G10 for pectoralis major MT, while G10 showed higher increases in quadriceps MT
than G5 (p<0.05). Conclusions: Five to 10 sets per week might be sufficient for attaining gains
in muscle size and strength in trained women during a 24-week RT program. There appears no
further benefit by performing higher exercise volumes. Since lack of time is a commonly cited
barrier to exercise adoption, our data supports RT programs that are less time consuming, which
might increase participation and adherence.
The present study compared the effects of two weekly-equalized volume and relative load interventions on body composition, strength and power. Based on individual baseline maximal strength values, eighteen recreationally trained men were pair-matched and consequently randomly assigned to one of the following experimental groups: a low volume per session with a high frequency (LV-HF, n = 9) group who trained 4-days (Mondays, Tuesdays, Thursdays and Fridays) or a high volume per session and low frequency (HV-LF, n = 9) group who trained 2-days (Mondays and Thursdays). Both groups performed two different routines over 6 weeks. Participants were tested pre- and post- intervention for maximal strength, upper body power, fat-free mass, limb circumferences and muscle thickness. Compared to baseline values, both groups increased their fat-free mass (HV-LF +1.19 ± 1.94; LV-HF +1.36 ± 1.06 kg, p<0.05) and vastus medialis thickness (HV-LF +2.18±1.88, p<0.01; LV-HF +1.82±2.43 mm, p<0.05), but only the HV-LF group enhanced arm circumference (1.08±1.47cm, p<0.05), elbow flexors thickness (2.21±2.81 mm, P<0.01) values and decreased their fat mass (-2.41 ± 1.10, P<0.01). Both groups improved (p<0.01) the maximal loads lifted in the bench press (LV-HF +0.14 ± 0.01; HV-LF +0.14 ± 0.01 kg.body mass-1) and the squat (LV-HF +0.14 ± 0.06; HV-LF 0.17 ± 0.01 kg.body mass-1) exercises as well as in upper body power (LV-HF +0.22 ± 0.25; HV-LF +0.27 ± 0.22 watts.body mass-1) Although both training strategies improved performance and lower body muscle mass, only the HV-LF protocol increased upper body hypertrophy and improved body composition.
Prior resistance training (RT) recommendations and position stands have discussed variables that can be manipulated when producing RT interventions. However, one variable that has received little discussion is set end points (i.e. the end point of a set of repetitions). Set end points in RT are often considered to be proximity to momentary failure and are thought to be a primary variable determining effort in RT. Further, there has been ambiguity in use and definition of terminology that has created issues in interpretation of research findings. The purpose of this paper is to: 1) provide an overview of the ambiguity in historical terminology around set end points; 2) propose a clearer set of definitions related to set end points; and 3) highlight the issues created by poor terminology and definitions. It is hoped this might permit greater clarity in reporting, interpretation, and application of RT interventions for researchers and practitioners.
This study investigated the time course of 96 h of muscle recovery after three different chest-press exercises with different stability requirements in resistance-trained men. Twenty-seven men (23.5±3.8 years) were randomly assigned to one of three groups: 1) Smith machine bench press; 2) barbell bench press; or 3) dumbbell bench press. Participants performed 8 sets of 10 repetition maximum with 2 min rest between sets. Muscle thickness, peak torque (PT), and soreness were measured pre, post, 24, 48, 72 and 96 h following exercise. There were no differences in the time course of PT or muscle thickness values of the pectoralis major (p=0.98 and p=0.91, respectively) or elbow extensors (p=0.07 and p=0.86, respectively) between groups. Muscle soreness of the pectoralis major was also not different between groups (p>0.05). However, the Smith machine and barbell groups recovered from triceps brachii muscle soreness by 72 h post-exercise (p>0.05), while the dumbbell group did not present any triceps brachii muscle soreness after exercise (p>0.05). In conclusion, resistance-trained men experience similar muscle damage recovery following Smith machine, barbell and dumbbell chest-press exercise. However, muscle soreness of the elbow extensors takes a longer time to recover after using a barbell chest-press exercise.
This study compared the time course of elbow flexor muscle recovery after multi- and single-joint exercises in highly resistance trained men. Sixteen men (24.5 ± 5.5 years) performed, in a counterbalanced order, 8 sets of 10 repetition maximum (RM) unilateral seated row exercise, and 8 sets of 10 RM unilateral biceps preacher curl exercise using the contralateral arm. Maximum isometric peak torque (PT), and delayed-onset muscle soreness (DOMS) were recorded at baseline (PRE), 10 minutes, 24, 48, 72 and 96 hours after each exercise protocol. There was a significant decrease (P<0.05) in elbow flexor PT 10 minutes after both the multi- and single-joint exercise sessions. However, PT decrease was greater after single-joint (26.8%) when compared to multi-joint (15.1%) exercise (P<0.05). In addition, elbow flexor PT was lower (8.4%) than baseline 24 hours after the single-joint exercise (P<0.01), whereas PT returned to baseline 24 hours after the multi-joint exercise. Compared to baseline, DOMS increased at 24, 48 and 72 hours post single-joint exercise (P<0.05). However, DOMS returned to baseline levels after 72 hours post multi-joint exercise. In addition, DOMS after single-joint exercise was greater (P<0.05) than after multi-joint exercise at 24, 48 and 72 hours post exercise. Our data suggest that after a resistance training session, highly resistance trained men experience dissimilar elbow flexor strength recovery between single-joint and multi-joint exercises. Likewise, elbow flexor DOMS is greater and takes longer to recover after single-joint exercise.
The present study tested the hypothesis that resistance-trained individuals would also show less muscle damage in the second than the first eccentric exercise bout (i.e. repeated bout effect) as shown in untrained individuals. This study investigated changes in indirect markers of muscle damage following 2 bouts of free weight eccentric exercise performed by 8 resistance-trained men. The participants (24.4 ± 1.2 years) performed 4 sets of 8 eccentric actions (3 s for each repetition) at 70% of eccentric 1 repetition maximum (1RM) load in a bench press exercise with a 2-minute rest between sets, and repeated the same exercise 2 weeks later. Bench press 1RM, delayed onset muscle soreness (DOMS) assessed by a 6-point Likert scale, serum creatine kinase activity (CK) and plasma prostaglandin E2 concentration (PGE2) were measured before and 24, 48, 72 and 96 hours after the exercise, and the changes were compared between bouts. The changes in the variables were smaller (p < 0.05) after the second than the first bout indicated by a smaller decline in 1RM strength (1st bout: -10.2 ± 1.0% vs. 2nd bout: -5.7 ± 1.5%), peak DOMS (3.8 ± 0.4 vs. 1.7 ± 0.5), peak CK (637.3 ± 133.3 vs. 305.4 ± 63.6 IU.L-1) and peak PGE2 (761.2 ± 171.0 vs. 307.2 ± 48.3 pg.mL-1). These results show a typical repeated bout effect. Thus, it is concluded that the repeated bout effect occurs in resistance-trained individuals.
The aim of this study was to investigate the effects of a resistance training program with excessive training load and insufficient recovery time between bouts on muscle hypertrophy- and atrophy-related protein expression. Male Wistar rats were randomly assigned to either a trained (TR, N = 9) or a sedentary (SE, N = 9) group. The TR group was subjected to a 12-week resistance training program with excessive training load and insufficient recovery between bouts that was designed to induce plantaris muscle atrophy. After the 12-week experiment, the plantaris muscle was collected to analyze the cross-sectional area (CSA) of the muscle fibers, and MAFbx, MyoD, myogenin and IGF-I protein expression (Western blot). The CSA was reduced significantly (-17%, P < 0.05) in the TR group compared to the SE group. Reciprocally, there was a significant (P < 0.05) 20% increase in MAFbx protein expression, while the MyoD (-27%), myogenin (-29%) and IGF-I (-43%) protein levels decreased significantly (P < 0.05) in the TR group compared to the SE group. In conclusion, our data indicated that muscle atrophy induced by resistance training with excessive training load and insufficient recovery was associated with upregulation of the MAFbx catabolic protein and downregulation of the MyoD, myogenin and IGF-I anabolic proteins. These findings suggest that quantitative analysis of these proteins can be important and complementary with other biochemical markers to confirm a possible overtraining diagnosis.
Exercise-induced muscle damage is an important topic in exercise physiology. However several aspects of our understanding of how muscles respond to highly stressful exercise remain unclear In the first section of this review we address the evidence that exercise can cause muscle damage and inflammation in otherwise healthy human skeletal muscles. We approach this concept by comparing changes in muscle function (i.e., the force-generating capacity) with the degree of leucocyte accumulation in muscle following exercise. In the second section, we explore the cytokine response to 'muscle-damaging exercise', primarily eccentric exercise. We review the evidence for the notion that the degree of muscle damage is related to the magnitude of the cytokine response. In the third and final section, we look at the satellite cell response to a single bout of eccentric exercise, as well as the role of the cyclooxygenase enzymes (COX1 and 2). In summary, we propose that muscle damage as evaluated by changes in muscle function is related to leucocyte accumulation in the exercised muscles. 'Extreme' exercise protocols, encompassing unaccustomed maximal eccentric exercise across a large range of motion, generally inflict severe muscle damage, inflammation and prolonged recovery (> 1 week). By contrast, exercise resembling regular athletic training (resistance exercise and downhill running) typically causes mild muscle damage (myofibrillar disruptions) and full recovery normally occurs within a few days. Large variation in individual responses to a given exercise should, however be expected. The link between cytokine and satellite cell responses and exercise-induced muscle damage is not so clear The systemic cytokine response may be linked more closely to the metabolic demands of exercise rather than muscle damage. With the exception of IL-6, the sources of systemic cytokines following exercise remain unclear The satellite cell response to severe muscle damage is related to regeneration, whereas the biological significance of satellite cell proliferation after mild damage or non-damaging exercise remains uncertain. The COX enzymes regulate satellite cell activity, as demonstrated in animal models; however the roles of the COX enzymes in human skeletal muscle need further investigation. We suggest using the term 'muscle damage' with care. Comparisons between studies and individuals must consider changes in and recovery of muscle force-generating capacity.
Comparisons between men and women of time course responses of strength, delayed-onset muscle soreness (DOMS), and muscle swelling after a resistance training session are still controversial. Therefore, this study examined gender differences in strength loss, muscle thickness (MT), and DOMS between young men and women. Thirty apparently healthy, untrained volunteers (14 women and 16 men) participated in the study protocol. The resistance exercise session consisted of 8 sets at 10 repetition maximum load of the elbow flexor muscles of their dominant arm. Maximum isokinetic peak torque (PT), MT, and DOMS were recorded at baseline (TB), immediately after exercise (T0), and at 1 (T1), 2 (T2), 3 (T3), and 4 (T4) days after exercise. Baseline strength was expressed as 100%. There were no significant differences between the sexes for relative PT loss immediately after exercise (T0 = 74.31 ± 8.26% for men and 76.00 ± 6.31% for women). Also, PT was still significantly less than baseline from T1 to T4 for both genders. In contrast, recovery from PT was longer in women when compared with that in men. Muscle thickness responded similarly to PT in both genders. However, there was no significant difference between genders for DOMS at any time point. The time point that showed the greatest degree of mean soreness was T2 (4.94 ± 2.38 mm for men and 4.45 ± 2.07 mm for women). Our data suggest that after resistance exercise, women and men experience similar immediate strength loss; however they have dissimilar strength recovery across 4 days of recovery. Likewise, both genders experience a different time course of MT response after a traditional resistance exercise protocol. In contrast, men and women develop and dissipate muscle soreness in a similar manner.
The aim of this study was to test whether high-intensity resistance training with insufficient recovery time between bouts, could result in a decrease of muscle fiber cross-sectional area (CSA), alter fiber-type frequencies and myosin heavy chain (MHC) isoform content in rat skeletal muscle. Wistar rats were divided into two groups: trained (Tr) and control (Co). Tr group were subjected to a high-intensity resistance training program (5 days/week) for 12 weeks, involving jump bouts into water, carrying progressive overloads based on percentage body weight. At the end of experiment, animals were sacrificed, superficial white (SW) and deep red (DR) portions of the plantaris muscle were removed and submitted to mATPase histochemical reaction and SDS-PAGE analysis. Throughout the experiment, both groups increased body weight, but Tr was lower than Co. There was a significant reduction in IIA and IID muscle fiber CSA in the DR portion of Tr compared to Co. Muscle fiber-type frequencies showed a reduction in Types I and IIA in the DR portion and IID in the SW portion of Tr compared to Co; there was an increase in Types IIBD frequency in the DR portion. Change in muscle fiber-type frequency was supported by a significant decrease in MHCI and MHCIIa isoforms accompanied by a significant increase in MHCIIb isoform content. MHCIId showed no significant differences between groups. These data show that high-intensity resistance training with insufficient recovery time between bouts promoted muscle atrophy and a transition from slow-to-fast contractile activity in rat plantaris muscle.
Eccentric muscle actions cause muscle damage and lead to delayed-onset muscle soreness (DOMS), which may impair performance. The purpose of this study was to examine the effect of DOMS on elbow flexion strength and rate of velocity development (RVD). Nineteen college male subjects performed 6 tests (pre- and posteccentric and every 24 hours for 4 days). In the preeccentric tests, each subject reported his arm pain and then did 5 concentric repetitions of elbow flexion/extension on an isokinetic dynamometer at 240 degrees x s(-1). Each subject then completed 6 sets of 10 eccentric elbow flexion actions at 30 degrees x s(-1) and finished with a posteccentric test with another 5 concentric repetitions at 240 degrees x s(-1). On days 1-4, each subject reported his arm pain and then did 5 more repetitions at 240 degrees x s(-1). Analysis was performed on the values for DOMS, peak torque (PT), and RVD. For DOMS, scores on the posteccentric test (2.34 +/- 2.53), day 1 (3.18 +/- 2.18), day 2 (3.21 +/- 2.91), day 3 (1.81 +/- 1.78), and day 4 (1.02 +/- 1.30) were all significantly (p < 0.05) greater than the preeccentric scores (0.00 +/- 0.00). For PT, the scores on the posteccentric test (22.40 +/- 8.87 ft x lb(-1)) and day 1 (23.88 +/- 9.00 ft x lb(-1)) were both significantly less than on the preeccentric test (29.56 +/- 8.42 ft x lb(-1)). The RVD scores on the posteccentric test (1505.73 +/- 462.12 d x s(-1) x s(-1)), day 1 (1571.55 +/- 475.99 d x s(-1) x s(-1)), and day 2 (1546.99 +/- 494.52 d x s(-1) x s(-1)) were all significantly less than on the preeccentric test (1719.86 +/- 473.18 d x s(-1) x s(-1)). This suggests that muscle damage may cause significant decreases in elbow flexion concentric strength and RVD even as DOMS remains elevated.
This study compared four different intensities of a bench press exercise for muscle soreness, creatine kinase activity, interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha (TNF-alpha), and prostaglandin E(2) (PGE(2)) concentrations in the blood. Thirty-five male Brazilian Army soldiers were randomly assigned to one of five groups: 50% one-repetition maximum (1-RM), 75% 1-RM, 90% 1-RM, 110% 1-RM, and a control group that did not perform the exercise. The total volume (sets x repetitions x load) of the exercise was matched among the exercise groups. Muscle soreness and plasma creatine kinase activity increased markedly (P < 0.05) after exercise, with no significant differences among the groups. Serum PGE(2) concentration also increased markedly (P < 0.05) after exercise, with a significantly (P < 0.05) greater increase in the 110% 1-RM group compared with the other groups. A weak but significant (P < 0.05) correlation was found between peak muscle soreness and peak PGE(2) concentration, but no significant correlation was evident between peak muscle soreness and peak creatine kinase activity, or peak creatine kinase activity and peak PGE(2) concentration. All groups showed no changes in IL-1beta, IL-6 or TNF-alpha. Our results suggest that the intensity of bench press exercise does not affect the magnitude of muscle soreness and blood markers of muscle damage and inflammation.
The objective of this review is to evaluate the measurement tools currently used in the study of eccentric contraction-induced muscle injury, with emphasis on their usefulness for quantifying the magnitude and duration of the injury and as indicators of muscle functional deficits. In studies in humans, it was concluded that measurements of maximal voluntary contraction torque and range of motion provide the best methods for quantifying muscle injury. Similarly, in animal studies, the in vitro measurement of electrically elicited force under isometric conditions was considered to be the best of the measurement tools currently in use.
For future studies, more effort should be put into measuring other contractile parameters (e.g. force/torque-velocity and force/torque-length relationships, maximal shortening velocity and fatigue susceptibility) that may reflect injury-induced functional impairments. The use of histology, ratings of soreness and the measurement of blood or bath levels of myofibre proteins should be discouraged for purposes of quantifying muscle injury and/or functional impairment.
This study investigated the effects of muscle glycogen availability on performance and selected physiological and metabolic responses during high-intensity intermittent exercise. Seven male subjects completed a regimen of exercise and dietary intake (48 h) to either lower and keep low (LOW-CHO) or lower and then increase (HIGH-CHO) muscle glycogen stores, on two separate occasions at least a week apart. On each occasion the subjects completed a short-term (<10 min) and prolonged (>30 min) intermittent exercise (IEX) protocol, 24 h apart, which consisted of 6-s bouts of high-intensity exercise performed at 30-s intervals on a cycle ergometer. Glycogen concentration (mean +/- SEM) in m. vastus lateralis before both IEx(short) and IEx(long) was significantly lower following LOW-CHO [180 (14), 181 (17) mmol kg (dw)(-1)] compared with HIGH-CHO [397 (35), 540 (25) mmol kg (dw)(-1)]. In both IEx(short) and IEx(long), significantly less work was performed following LOW-CHO compared with HIGH-CHO. In IEx(long), the number of exercise bouts that could be completed at a pre-determined target exercise intensity increased by 265% from 111 (14) following LOW-CHO to 294 (29) following HIGH-CHO (P < 0.05). At the point of fatigue in IEx(long), glycogen concentration was significantly lower with the LOW-CHO compared with HIGH-CHO [58 (25) vs. 181 (46) mmol kg (dw)(-1), respectively]. The plasma concentrations of adrenaline and nor-adrenaline (in IEx(short) and IEx(long)), and FFAand glycerol (in IEx(long)), increased several-fold above resting values with both experimental conditions. Oxygen uptake during the exercise periods in IEx(long), approached 70% of Vo2max. These results suggest that muscle glycogen availability can affect performance during both short-term and more prolonged high-intensity intermittent exercise and that with repeated exercise periods as short as 6 s, there can be a relatively high aerobic contribution.
This study investigated whether performing repeated bouts of maximal voluntary isokinetic eccentric exercise (MAX1) on 3 (MAX3) and 6 days (MAX6) after the initial bout would produce significant changes in the indirect markers of muscle damage and total work. A secondary purpose was to determine whether participants' psychological maximal effort was equivalent to the physiological maximal effort during muscle soreness. Male university students were assigned randomly to a control group (n = 12) and a group that repeated the exercise (EX; n = 12). The MAX1 was 3 x 10 repetitions of the nondominant elbow flexors on the Cybex 6000 system at a speed of 60 deg/s. The EX group performed the same exercise 3 days and 6 days after MAX1. The range of motion and maximal isometric force (MIF), muscle soreness index, plasma creatine kinase, and glutamic-oxaloacetate transaminase activities were measured before and every 24 hr for 9 days after MAX1 for both groups. MIF was also assessed once before and immediately after each MAX for the EX group. There were no significant changes (p > .05) between the groups for all criterion measures, except for total amount of work (p < .05). It is concluded that strenuous voluntary isokinetic eccentric exercise performed with damaged muscles does not appear to exacerbate damage or influence the recovery process. Although individuals could perform repeated MAXs, the total work performed was significantly reduced. This has practical implications in strength training for coaches and athletes during muscle damage.
This study examined whether a second bout of maximal eccentric exercise performed 3 days after the first exercise bout would produce further changes in muscle damage and electromyographic activity (EMG). Male students (n=26) were randomly assigned to experimental 70 (EX70; n=9), experimental 30 (EX30; n=8), and control (CON; n=9) groups. The initial exercise was 30 maximal voluntary isokinetic eccentric contractions (MAX1) on non-dominant elbow flexors at 60 degrees s(-1) (1.05 rad s(-1)). The EX70 and EX30 groups performed a second bout of 70 and 30 eccentric contractions (MAX2), respectively, 3 days after MAX1. Upper arm circumference, range of motion, strength, integrated EMG (IEMG), and mean power frequency (MPF) were measured before, immediately after, and once a day for 9 days after MAX1. Plasma creatine kinase (CK) activity and muscle soreness were assessed before and for 9 days after MAX1. Total work, work per contraction, IEMG, and MPF were also recorded during MAX1 and MAX2. All indicators of muscle damage changed following MAX1 for each group (P<0.05), but no indicators of additional damage (P>0.05) were apparent after MAX2 for either the EX70 or EX30 groups. IEMG (P=0.03) and MPF (P=0.04) were lower for MAX2 compared with MAX1 for both the EX30 and EX70 groups. It is concluded that performing a second bout of eccentric exercise with damaged muscles 3 days after the initial bout does not produce further damage or retard recovery, even when the second bout of exercise is more strenuous. EMG findings were consistent with reduced activation of fast-twitch motor units during the second eccentric bout. These results may be interpreted as evidence of a neural protective mechanism.
To establish normative data for muscle performance during isokinetic horizontal abduction and adduction of the shoulder in elite junior tennis players.
Thirty six tennis players were evaluated (23 male, 13 female; mean age 14 years (range 12-18)). An isokinetic dynamometer was used to test the shoulder horizontal abductors and adductors at 60 and 180 degrees/s. Absolute and relative peak torque (PT and PT/BW), total work (TW), endurance ratio (ER), and the ratio of the peak torque between horizontal abductors and adductors (HAB/HAD ratio) were recorded. Data were compared for the dominant and non-dominant shoulders, horizontal abductor and adductor muscles, and between players grouped according to age.
The dominant shoulder was significantly (p<0.05) stronger than the non-dominant shoulder in all variables except ER and HAB/HAD ratio. The abductors were significantly (p<0.05) weaker than the adductors in all subjects. The type of backhand (one handed or two handed) did not influence the strength of the shoulder horizontal abductors on the dominant side. The number of years of tennis practice had an effect on muscle strength as evaluated by absolute data (PT and TW) but not relative measurements (PT/BW and TW/BW).
The findings confirm that horizontal abduction and adduction are stronger in the dominant shoulder of junior tennis players. The clinical relevance of these findings is not established, and more studies are needed to compare tennis players with athletes from other sports and non-athletes.
This article critically discusses whether accumulation of lactic acid, or in reality lactate and/or hydrogen (H+) ions, is a major cause of skeletal muscle fatigue, i.e. decline of muscle force or power output leading to impaired exercise performance. There exists a long history of studies on the effects of increased lactate/H+ concentrations in muscle or plasma on contractile performance of skeletal muscle. Evidence suggesting that lactate/H+ is a culprit has been based on correlation-type studies, which reveal close temporal relationships between intramuscular lactate or H+ accumulation and the decline of force during fatiguing stimulation in frog, rodent or human muscle. In addition, an induced acidosis can impair muscle contractility in non-fatigued humans or in isolated muscle preparations, and several mechanisms to explain such effects have been provided. However, a number of recent high-profile papers have seriously challenged the ‘lactic acid hypothesis’. In the 1990s, these findings mainly involved diminished negative effects of an induced acidosis in skinned or intact muscle fibres, at higher more physiological experimental temperatures. In the early 2000s, it was conclusively shown that lactate has little detrimental effect on mechanically skinned fibres activated by artificial stimulation. Perhaps more remarkably, there are now several reports of protective effects of lactate exposure or induced acidosis on potassium-depressed muscle contractions in isolated rodent muscles. In addition, sodium-lactate exposure can attenuate severe fatigue in rat muscle stimulated in situ, and sodium lactate ingestion can increase time to exhaustion during sprinting in humans. Taken together, these latest findings have led to the idea that lactate/ H+ is ergogenic during exercise.
It should not be taken as fact that lactic acid is the deviant that impairs exercise performance. Experiments on isolated muscle suggest that acidosis has little detrimental effect or may even improve muscle performance during high-intensity exercise. In contrast, induced acidosis can exacerbate fatigue during whole-body dynamic exercise and alkalosis can improve exercise performance in events lasting 1–10 minutes. To reconcile the findings from isolated muscle fibres through to whole-body exercise, it is hypothesised that a severe plasma acidosis in humans might impair exercise performance by causing a reduced CNS drive to muscle.
This study compared resistance-trained and untrained men for changes in commonly used indirect markers of muscle damage after maximal voluntary eccentric exercise of the elbow flexors. Fifteen trained men (28.2 +/- 1.9 years, 175.0 +/- 1.6 cm, and 77.6 +/- 1.9 kg) who had resistance trained for at least 3 sessions per week incorporating exercises involving the elbow flexor musculature for an average of 7.7 +/- 1.4 years, and 15 untrained men (30.0 +/- 1.5 years, 169.8 +/- 7.4 cm, and 79.9 +/- 4.4 kg) who had not performed any resistance training for at least 1 year, were recruited for this study. All subjects performed 10 sets of 6 maximal voluntary eccentric actions of the elbow flexors of one arm against the lever arm of an isokinetic dynamometer moving at a constant velocity of 90 degrees .s. Changes in maximal voluntary isometric and isokinetic torque, range of motion, upper arm circumference, plasma creatine kinase activity, and muscle soreness before, immediately after, and for 5 days after exercise were compared between groups. The trained group showed significantly (P < 0.05) smaller changes in all of the measures except for muscle soreness and faster recovery of muscle function compared with the untrained group. For example, muscle strength of the trained group recovered to the baseline by 3 days after exercise, where the untrained group showed approximately 40% lower strength than baseline. These results suggest that resistance-trained men are less susceptible to muscle damage induced by maximal eccentric exercise than untrained subjects.
-Nine male subjects performed two bouts of 30-s maximal isokinetic cycling. Each bout of exercise was performed at 80 revolutions/min and was separated by 4 min of recovery. Mixed-muscle phosphocreatine (: PCr resynthesis during recovery (88.1 ±6.1%) was positively correlated with the restoration of total work production during bout 2 (r = 0.80, P < 0.05). During bout 1, ATP and PCr utilization were greater in type II compared with type I fibers (P < 0.01 and P< 0.05, respectively). The subsequent 4-min period of recovery was insufficient to allow total restoration of ATP and PCr in type II fibers, but restoration of ATP and PCr in type I fibers was almost complete. During the second bout of exercise, ATP and PCr utilization were reduced in type II fibers (P < 0.01), without a corresponding change in type I fibers, and performance was also significantly reduced. The reduction in work capacity observed during bout 2 may have been related to a slower resynthesis, and consequently a reduced availability, of ATP and PCr in type II fibers.
The effects of heavy resistance exercise on skeletal muscle androgen receptor (AR) protein concentration and mRNAs of AR, insulin-like growth factor-I (IGF)-IEa, and mechano growth factor (MGF) expression were examined from biopsies of vastus lateralis (VL) muscle before and 48 hours after heavy resistance exercise (5 × 10 repetition maximum [RM] leg press and 4 × 10RM squats) in 8 adult strength trained men. The present exercise induced an acute decrease in maximal isometric force and increased serum total testosterone (T) and free testosterone (FT) concentrations. During 2 recovery days, maximal isometric force and subjective perception of physical fitness remained significantly lowered, whereas serum creatine kinase activity, subjective muscle soreness, and muscle swelling (i.e., thickness of VL by ultrasound) were significantly increased compared to pre-exercise values. Subjective perception of physical fitness was followed up to 7 days, and by 6 days postexercise, it was elevated above the pre-exercise level. Basal T and FT concentrations remained unaltered after the exercise. No statistically significant changes were observed in AR protein or mRNA expression, but IGF-IEa (p < 0.05) and MGF (p < 0.05) mRNA expression were increased compared to pre-exercise levels. These findings indicate that IGF-IEa and MGF responses may be related to acute regenerative processes in muscle because of exercise and may contribute to muscular adaptation to resistance exercise. Subjective perception of physical fitness suggests that recovery over a preexercise level of the present type of heavy resistance exercise can take approximately 6 days.
The theory of training was established about five decades ago when knowledge of athletes' preparation was far from complete and the biological background was based on a relatively small amount of objective research findings. At that time, traditional 'training periodization', a division of the entire seasonal programme into smaller periods and training units, was proposed and elucidated. Since then, international sport and sport science have experienced tremendous changes, while the traditional training periodization has remained at more or less the same level as the published studies of the initial publications. As one of the most practically oriented components of theory, training periodization is intended to offer coaches basic guidelines for structuring and planning training. However, during recent decades contradictions between the traditional model of periodization and the demands of high-performance sport practice have inevitably developed. The main limitations of traditional periodization stemmed from: (i) conflicting physiological responses produced by 'mixed' training directed at many athletic abilities; (ii) excessive fatigue elicited by prolonged periods of multi-targeted training; (iii) insufficient training stimulation induced by workloads of medium and low concentration typical of 'mixed' training; and (iv) the inability to provide multi-peak performances over the season. The attempts to overcome these limitations led to development of alternative periodization concepts. The recently developed block periodization model offers an alternative revamped approach for planning the training of high-performance athletes. Its general idea proposes the sequencing of specialized training cycles, i.e. blocks, which contain highly concentrated workloads directed to a minimal number of targeted abilities. Unlike the traditional model, in which the simultaneous development of many athletic abilities predominates, block-periodized training presupposes the consecutive development of reasonably selected target abilities. The content of block-periodized training is set down in its general principles, a taxonomy of mesocycle blocks, and guidelines for compiling an annual plan.
The supply of energy is of fundamental importance for the ability to sustain exercise. The maximal duration of exercise is negatively related to the relative intensity both during dynamic and static exercise. Since exercise intensity is linearly related to the rate of energy utilisation this suggests that energetic deficiency plays a major role in the aetiology of muscle fatigue. Characteristic metabolic changes in the muscle are generally observed at fatigue--the pattern being different after short term exercise (lactate accumulation and phosphocreatine depletion) from after prolonged exercise at moderate intensity (glycogen depletion). A common metabolic denominator at fatigue during these and many other conditions is a reduced capacity to generate ATP and is expressed by an increased catabolism of the adenine nucleotide pool in the muscle fibre. Transient increases in ADP are suggested to occur during energetic deficiency and may be the cause of fatigue. Experimental evidence from human studies demonstrate that near maximal power output can be attained during acidotic conditions. Decreases in muscle pH is therefore unlikely to affect the contractile machinery by a direct effect. However, acidosis may interfere with the energy supply possibly by reducing the glycolytic rate, and could by this mechanism be related to muscle fatigue.
Nine male subjects performed two bouts of 30-s maximal isokinetic cycling. Each bout of exercise was performed at 80 revolutions/min and was separated by 4 min of recovery. Mixed-muscle phosphocreatine (PCr) resynthesis during recovery (88.1 +/- 6.1%) was positively correlated with the restoration of total work production during bout 2 (r = 0.80, P < 0.05). During bout 1, ATP and PCr utilization were greater in type II compared with type I fibers (P < 0.01 and P < 0.05, respectively). The subsequent 4-min period of recovery was insufficient to allow total restoration of ATP and PCr in type II fibers, but restoration of ATP and PCr in type I fibers was almost complete. During the second bout of exercise, ATP and PCr utilization were reduced in type II fibers (P < 0.01), without a corresponding change in type I fibers, and performance was also significantly reduced. The reduction in work capacity observed during bout 2 may have been related to a slower resynthesis, and consequently a reduced availability, of ATP and PCr in type II fibers.
We have recently shown that eccentric contractions (Ecc) of rat calf muscles cause muscle damage and decreased glycogen and glucose transporter GLUT-4 protein content in the white (WG) and red gastrocnemius (RG) but not in the soleus (S) (S. Asp, S. Kristiansen, and E. A. Richter. J. Appl. Physiol. 79: 1338-1345, 1995). To study whether these changes affect insulin action, hindlimbs were perfused at three different insulin concentrations (0, 200, and 20,000 microU/ml) 2 days after one-legged eccentric contractions of the calf muscles. Compared with control, basal glucose transport was slightly higher (P < 0.05) in Ecc-WG and -RG, whereas it was lower (P < 0.05) at both submaximal and maximal insulin concentrations in the Ecc-WG and at maximal concentrations in the Ecc-RG. In the Ecc-S, the glucose transport was unchanged in hindquarters perfused in the absence or presence of a submaximal stimulating concentration of insulin, whereas it was slightly (P < 0.05) higher during maximal insulin stimulation compared with control S. At the end of perfusion the glycogen concentrations were lower in both Ecc-gastrocnemius muscles compared with control muscles at all insulin concentrations. Fractional velocity of glycogen synthase increased similarly with increasing insulin concentrations in Ecc- and control WG and RG. We conclude that insulin action on glucose transport but not glycogen synthase activity is impaired in perfused muscle exposed to prior eccentric contractions.
A common belief in exercise physiology is that fatigue during exercise is caused by changes in skeletal muscle metabolism. This 'peripheral' fatigue results either from substrate depletion during submaximal exercise or metabolite accumulation during maximal exercise in the exercising muscles. However, if substrate depletion alone caused fatigue, intracellular ATP levels would decrease and lead to rigor and cellular death. Alternatively, metabolite accumulation would prevent any increase in exercise intensity near the end of exercise. At present, neither of these effects has been shown to occur, which suggests that fatigue may be controlled by changes in efferent neural command, generally described as 'central' fatigue. In this review, we examine neural efferent command mechanisms involved in fatigue, including the concepts of muscle wisdom during short term maximal activity, and muscle unit rotation and teleoanticipation during submaximal endurance activity. We propose that neural strategies exist to maintain muscle reserve, and inhibit exercise activity before any irreparable damage to muscles and organs occurs. The finding that symptoms of fatigue occur in the nonexercising state in individuals with chronic fatigue syndrome indicates that fatigue is probably not a physiological entity, but rather a sensory manifestation of these neural regulatory mechanisms.
This study examined the effects of a 7-d repeated maximal isokinetic eccentric training period on the indicators of muscle damage and inflammatory response.
Twenty-two college-age males were randomly assigned to eccentric training (ET) (N = 12) and control groups (CON) (N = 10). The initial exercise was 30 repetitions of maximal voluntary isokinetic eccentric contraction (ECC1) on nondominant elbow flexors with Cybex 6000 at 60 degrees.s-1 angular velocity. The ET group performed the same exercise for the following 6 consecutive days (referred to as ECC2 to ECC7) after ECC1. Upper arm circumference (CIR), range of motion (ROM), and maximal isometric force (MIF) were measured before, immediately after, and every 24 h for 7 consecutive days after ECC1. Plasma creatine kinase (CK), lactate dehydrogenase (LDH), glutamic oxaloacetate transaminase (GOT), leukocyte counts, and serum interleukin-1beta and -6 (IL-1beta, IL-6) levels were assessed before; at 2 h; and at 1, 3, 4, 6, and 7 d after ECC1. Muscle soreness was measured before and for 7 consecutive days after ECC1.
The ECC1 produced significant changes in most of the measures for both groups (P < 0.05), with the exception of leukocyte counts (P > 0.05). No indicators of increased damage (P > 0.05) were found from ECC2 to ECC7 for the ET group.
Continuous intensive isokinetic eccentric training performed with damaged muscles did not exacerbate muscle damage and inflammation after ECC1. In addition, a muscular "adaptation effect" may occur as early as 24 h after ECC1, as shown by the ET group's performance for 6 consecutive days after ECC1.
Exercise-induced muscle injury in humans frequently occurs after unaccustomed exercise, particularly if the exercise involves a large amount of eccentric (muscle lengthening) contractions. Direct measures of exercise-induced muscle damage include cellular and subcellular disturbances, particularly Z-line streaming. Several indirectly assessed markers of muscle damage after exercise include increases in T2 signal intensity via magnetic resonance imaging techniques, prolonged decreases in force production measured during both voluntary and electrically stimulated contractions (particularly at low stimulation frequencies), increases in inflammatory markers both within the injured muscle and in the blood, increased appearance of muscle proteins in the blood, and muscular soreness. Although the exact mechanisms to explain these changes have not been delineated, the initial injury is ascribed to mechanical disruption of the fiber, and subsequent damage is linked to inflammatory processes and to changes in excitation-contraction coupling within the muscle. Performance of one bout of eccentric exercise induces an adaptation such that the muscle is less vulnerable to a subsequent bout of eccentric exercise. Although several theories have been proposed to explain this "repeated bout effect," including altered motor unit recruitment, an increase in sarcomeres in series, a blunted inflammatory response, and a reduction in stress-susceptible fibers, there is no general agreement as to its cause. In addition, there is controversy concerning the presence of sex differences in the response of muscle to damage-inducing exercise. In contrast to the animal literature, which clearly shows that females experience less damage than males, research using human studies suggests that there is either no difference between men and women or that women are more prone to exercise-induced muscle damage than are men.
Overtraining syndrome is characterized by declining performance and transient inflammation following periods of severe training with major health implications for the athletes. Currently, there is no single diagnostic marker for overtraining. The present investigation examined the responses of oxidative stress biomarkers to a resistance training protocol of progressively increased and decreased volume/intensity. Twelve males (21.3+/-2.3 years) participated in a 12-week resistance training consisting of five 3-week periods (T1, 2 tones/week; T2, 8 tones/week; T3, 14 tones/week; T4, 2 tones/week), followed by a 3-week period of complete rest. Blood/urine samples were collected at baseline and 96 h following the last training session of each period. Performance (strength, power, jumping ability) increased after T2 and declined thereafter, indicating an overtraining response. Overtraining (T3) induced sustained leukocytosis, an increase of urinary isoprostanes (7-fold), TBARS (56%), protein carbonyls (73%), catalase (96%), glutathione peroxidase, and oxidized glutathione (GSSG) (25%) and a decline of reduced glutathione (GSH) (31%), GSH/GSSG (56%), and total antioxidant capacity. Isoprostanes and GSH/GSSG were highly (r=0.764-0.911) correlated with performance drop and training volume increase. In conclusion, overtraining induces a marked response of oxidative stress biomarkers which, in some cases, was proportional to training load, suggesting that they may serve as a tool for overtraining diagnosis.
Regulation of skeletal muscle mass is highly dependent on contractile loading. The purpose of this study was to examine changes in growth factor and inflammatory pathways following high-frequency resistance training.
Using a novel design in which male Sprague-Dawley rats undertook a "stacked" resistance training protocol designed to generate a summation of transient exercise-induced signaling responses (four bouts of three sets x 10 repetitions of squat exercise, separated by 3 h of recovery), we determined the effects of high training frequency on signaling pathways and transcriptional activity regulating muscle mass.
The stacked training regimen resulted in acute suppression of insulin-like growth factor 1 mRNA abundance (P < 0.05) and Akt phosphorylation (P < 0.05), an effect that persisted 48 h after the final training bout. Conversely, stacked training elicited a coordinated increase in the expression of tumor necrosis factor alpha, inhibitor kappa B kinase alpha/beta activity (P < 0.05), and p38 mitogen-activated protein kinase phosphorylation (P < 0.05) at 3 h after each training bout. In addition, the stacked series of resistance exercise bouts induced an increase in p70 S6 kinase phosphorylation 3 h after bouts x3 and x4, independent of the phosphorylation state of Akt.
Our results indicate that high resistance training frequency extends the transient activation of inflammatory signaling cascades, concomitant with persistent suppression of key mediators of anabolic responses. We provide novel insights into the effects of the timing of exercise-induced overload and recovery on signal transduction pathways and transcriptional activity regulating skeletal muscle mass in vivo.
Athletes spend a much greater proportion of their time recovering than they do in training. Yet, much attention has been given to training with very little investigation of recovery. The purpose of this review is to stimulate further research into this vital area of training. Recovery can be categorized in three terms: i) immediate recovery between exertions; ii) short-term recovery between repeats (e.g., between resistance sets or interval bouts); and iii) training recovery between workouts. The focus of this review is training recovery. Full training recovery is essential to optimal performance and improvement. This review includes an examination of extant research on recovery and a very brief review of some potential modalities and techniques for hastening recovery and the time course of recovery and responses to some treatments. Measures of recovery and practical considerations are discussed briefly. Much research is needed in this area, but there are obstacles to high quality research. Attention must be given to key issues in research on recovery, especially the individual response to recovery treatments.
- D V Ferreira
D.V. Ferreira et al.
Physiology & Behavior 179 (2017) 143–147
- V Ferreira
V. Ferreira et al.
Physiology & Behavior 179 (2017) 143-147