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The greater muscle fiber cross-sectional area (CSA) is associated with greater skeletal muscle mass and strength, whereas muscle fiber atrophy is considered a major feature of sarcopenia. Muscle fiber size is a polygenic trait influenced by both environmental and genetic factors. However, the genetic variants underlying inter-individual differences in muscle fiber size remain largely unknown. The aim of our study was to determine whether 1535 genetic variants previously identified in a genome-wide association study of appendicular lean mass are associated with the CSA of fast-twitch muscle fibers (which better predict muscle strength) in the m. vastus lateralis of 148 physically active individuals (19 power-trained and 28 endurance-trained females, age 28.0 ± 1.1; 28 power-trained and 73 endurance-trained males, age 31.1 ± 0.8). Fifty-seven single-nucleotide polymorphisms (SNPs) were identified as having an association with muscle fiber size (p < 0.05). Of these 57 SNPs, 31 variants were also associated with handgrip strength in the UK Biobank cohort (n = 359,729). Furthermore, using East Asian and East European athletic (n = 731) and non-athletic (n = 515) cohorts, we identified 16 SNPs associated with athlete statuses (sprinter, wrestler, strength, and speed-strength athlete) and weightlifting performance. All SNPs had the same direction of association, i.e., the lean mass-increasing allele was positively associated with the CSA of muscle fibers, handgrip strength, weightlifting performance, and power athlete status. In conclusion, we identified 57 genetic variants associated with both appendicular lean mass and fast-twitch muscle fiber size of m. vastus lateralis that may, in part, contribute to a greater predisposition to power sports.

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PURPOSE: Resistance training (RT) induces muscle growth at varying rates across RT phases, and evidence suggests that the muscle-molecular responses to training bouts become refined or attenuated in the trained state. This study examined how proteolysis-related biomarkers and extracellular matrix (ECM) remodeling factors respond to a bout of RT in the untrained (UT) and trained (T) state. METHODS: Participants (19 women and 19 men) underwent 10 weeks of RT. Biopsies of vastus lateralis were collected before and after (24 h) the first (UT) and last (T) sessions. Vastus lateralis cross-sectional area (CSA) was assessed before and after the experimental period. RESULTS: There were increases in muscle and type II fiber CSAs. In both the UT and T states, calpain activity was upregulated and calpain-1/-2 protein expression was downregulated from Pre to 24 h. Calpain-2 was higher in the T state. Proteasome activity and 20S proteasome protein expression were upregulated from Pre to 24 h in both the UT and T. However, proteasome activity levels were lower in the T state. The expression of poly-ubiquitinated proteins was unchanged. MMP activity was downregulated, and MMP-9 protein expression was elevated from Pre to 24 h in UT and T. Although MMP-14 protein expression was acutely unchanged, this marker was lower in T state. TIMP-1 protein levels were reduced Pre to 24 h in UT and T, while TIMP-2 protein levels were unchanged. CONCLUSION: Our results are the first to show that RT does not attenuate the acute-induced response of proteolysis and ECM remodeling-related biomarkers.

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Masseter hypertrophy (MH) is an uncommon natural condition that affects the facial contour. The etiology is debatable, and complaints are usually cosmetic in nature. The diagnosis is essentially clinical and aided by imaging tests. Treatment is still controversial. The literature is relatively scarce in relation to information on MH, particularly in the evaluation of outcomes. Through questionnaires, the progress was observed in the evaluation of the outcomes of aesthetic procedures. Thus, the purpose of this paper is to apply a Facelift Outcome Evaluation (FOE) questionnaire to evaluate the outcomes of surgical treatment in a case of MH. A 23-year-old male presented to the clinic complaining of bullying due to his facial aesthetics. Clinical and imaging evaluation was performed, with the creation of surgical guides. The patient answered the FOE questionnaire pre- and postoperatively, with results of 12.5 and 100.00 respectively. This subjectively shows the success of the treatment. We suggest that a questionnaire applied exclusively to masseter hypertrophy should be developed, as well as studies for the development of muscle volume measurement protocols, aiming at a more specific evaluation of the surgical outcomes.

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Cell swelling caused by resistance training is proposed to provide an anabolic stimulus for muscle growth and it is believed that these effects are heightened with the use of low loads. The purpose of this study was to compare the acute effects of two volume-equated resistance training (RT) protocols, low-load (LL) versus high-load (HL), on elbow flexor muscles thickness, arm circumference, and blood lactate concentration in well-trained individuals. Eight resistance-trained males performed the following two RT protocols involving unilateral elbow flexion of the dominant arm: i) LL, four sets with 50% 1 repetition-maximum [1 RM] and ii) HL, ten sets with 85% 1 RM until failure, and equated volume. Pre- and post-session measurements included muscle thickness of the elbow flexors (biceps brachii and brachialis), upper arm circumference, and blood lactate concentration. Significant pre- to post-session increases were found in both protocols for muscle thickness (F (1, 28) = 11.74, p = 0.0019), and blood lactate (F (1, 28) = 35.55, p < 0.0001); no statistically significant differences were observed between conditions, however, the magnitude of increases favored LL. Significant between-condition differences favoring LL were observed for total repetitions (p = 0.007), time under tension (p = 0.007), and training density (p = 0.007). These results suggest that LL training promotes superior post-session increases in muscle thickness, indicating that RT protocols with longer times under tension and densities are beneficial when the goal is to promote acute cell swelling.

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BACKGROUND AND AIMS: Fabry disease (FD) is an X-linked genetic lysosomal disease, in which a deficit in the alpha-galactosidase A enzyme results in lysosomal build-up of globotriaosylceramide in several organs, causing cardiac, renal and cerebrovascular complications. The aim of this study was to assess the prevalence of papillary muscle hypertrophy (PMH) in patients with FD. METHODS: A group of 63 patients with FD and a positive genetic diagnosis were studied and were divided into two groups: one included 24 patients with FD and LVH and another group included 39 patients with FD and without LVH. Papillary muscles were measured from the left parasternal short axis view, defining PMH as a diastolic thickness greater than 11 mm in any diameter. RESULTS: Patients with FD and LVH had a high prevalence of anterolateral PMH (66.6%), and such prevalence was lower for the posteromedial PMH (33.3%). However, patients who had not yet developed LVH had a high prevalence of anterolateral PMH (33.3%). CONCLUSIONS: Patients with FD in the pre-clinical stage (without LVH) have a high prevalence of PMH, especially involving the anterolateral papillary muscle. This finding could be an early marker for the development of LVH, allowing to suspect the disease during its early stages, and begin enzyme replacement therapy in the appropriate patients.

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A rare cause of limb ischemia in young patients, adductor canal syndrome, can be debilitating and result in functional impairment. Diagnosis and treatment may be delayed due to this vascular disease's rarity in young people and because the presenting symptoms can overlap with other more common causes of leg pain in young athletes. Here, authors discuss a young athletic patient with a history of year-long claudication. The patient's reported symptoms, exam findings, and imaging results were consistent with a diagnosis of adductor canal syndrome. This case proved uniquely challenging, given the extent of disease and illustrates potential approach considerations.

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El entrenamiento con restricción del flujo sanguíneo ha resultado ser una alternativa que logra resultados similares a los conseguidos por el entrenamiento de alta intensidad. El presente artículo ofrece el resultado de una investigación, en la que se realizó una revisión bibliográfica para indagar sobre la efectividad en el aumento de fuerza muscular, así como analizar los mecanismos de acción y metodología de aplicación práctica, mediante el método de restricción parcial de flujo sanguíneo con resistencia a bajas cargas. La literatura revisada respalda los efectos positivos de este método para generar hipertrofia y aumento de fuerza muscular, tanto en población sana como en periodo de rehabilitación. Los principales mecanismos propuestos como mediadores de esta adaptación son la elevación en la secreción de hormona del crecimiento, la señalización intracelular vía anabólica y catabólica y la contribución de procesos inflamatorios o edematosos. Se recomendó trabajar con cargas entre el 20 al 40 % de una repetición máxima y con un volumen de 75 repeticiones por sesión con entrenamiento entre 2 a 4 veces por semana, durante un tiempo mínimo de tres semanas. Se discutió sobre los efectos en la adaptación neurológica, sin existir evidencia que lo respalde. Se concluyó que el método de restricción parcial del flujo sanguíneo genera aumento de fuerza e hipertrofia y se recomienda como método complementario y alternativo al ejercicio de alta intensidad, en poblaciones que necesariamente se ven imposibilitadas de entrenar a altas intensidades.

SÍNTESE O treinamento com restrição do fluxo sanguíneo provou ser uma alternativa que alcança resultados similares aos alcançados pelo treinamento de alta intensidade. Este artigo oferece o resultado de uma pesquisa, na qual foi realizada uma revisão de literatura para investigar a eficácia no aumento da força muscular, bem como para analisar os mecanismos de ação e metodologia de aplicação prática, utilizando o método de restrição parcial do fluxo sanguíneo com resistência a cargas baixas. A literatura revisada apóia os efeitos positivos deste método para gerar hipertrofia e aumentar a força muscular, tanto na população saudável quanto no período de reabilitação. Os principais mecanismos propostos como mediadores desta adaptação são a elevada secreção hormonal de crescimento, a sinalização intracelular através de vias anabólicas e catabólicas e a contribuição de processos inflamatórios ou edematosos. Foi recomendado trabalhar com cargas entre 20 a 40% de uma repetição máxima e com um volume de 75 repetições por sessão com treinamento entre 2 a 4 vezes por semana, por um tempo mínimo de três semanas. Os efeitos sobre a adaptação neurológica foram discutidos, mas não há evidências que sustentem isto. Concluiu-se que o método de restrição parcial do fluxo sanguíneo gera maior força e hipertrofia e é recomendado como um método complementar e alternativo ao exercício de alta intensidade, em populações que são necessariamente incapazes de treinar em altas intensidades.

Blood flow restriction training has turned out to be an alternative that achieves results similar to those achieved by high intensity training. The present article offers the result of a research where, a bibliographical review was carried out to inquire about the effectiveness in increasing muscle strength, as well as to analyze the mechanisms of action and methodology of practical application, through the method of partial restriction of blood flow with endurance to low loads. The reviewed literature supports the positive effects of this method to generate hypertrophy and increase muscle strength, both in the healthy population and in the rehabilitation period. The main mechanisms proposed as mediators of this adaptation are increased secretion of growth hormone, intracellular signaling via anabolic and catabolic pathways, and the contribution of inflammatory or edematous processes. It was recommended to work with loads between 20 and 40 % of a maximum repetition and with a volume of 75 repetitions per session with training between 2 and 4 times a week, for a minimum of three weeks. The effects on neurological adaptation were discussed, without supporting evidence. It was concluded that the method of partial restriction of blood flow generates an increase in strength and hypertrophy and is recommended as a complementary and alternative method to high intensity exercise, in populations that are necessarily unable to train at high intensities.

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The mechanisms responsible for the similar muscle growth attained with high- and low-load resistance training (RT) have not yet been fully elucidated. One mechanism is related to the mechanical stimulus and the level of motor unit recruitment; another mechanism is related to the metabolic response. We investigated the electromyographic signal amplitude (sEMG) and the general metabolic response to high-load RT (HL) and low-load resistance training (LL). We measured muscle thickness by ultrasound, sEMG amplitude by electromyography, and analysis of metabolites expressed through metabolomics. No differences were observed between the HL and LL groups for metabolic response and muscle thickness. A greater amplitude of sEMG was observed in the HL group. In addition, a correlation was observed between changes in muscle thickness of the vastus lateralis muscle in the HL group and levels of the metabolites carnitine, creatine, 3-hydroxyisovalerate, phenylalanine, asparagine, creatine phosphate, and methionine. In the LL group, a correlation was observed between changes in muscle thickness of the vastus lateralis muscle and levels of the metabolites acetoacetate, creatine phosphate, and oxypurinol. These correlations seem to be related to the characteristics of activated muscle fibers, the metabolic demand of the training protocols used, and the process of protein synthesis.

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OBJECTIVE: The effects of ROM manipulation on muscle strength and hypertrophy response remain understudied in long-term interventions. Thus, we compared the changes in strength and regional muscle hypertrophy after training in protocols with different ranges of motion (ROM) in the seated dumbbell preacher curl exercise using a within-participant experimental design. DESIGN AND METHODS: Nineteen young women had one arm randomly assigned to train in the initial ROM (INITIALROM: 0°-68°; 0° = extended elbow) while the contralateral arm trained in the final ROM (FINALROM: 68°-135°), three times per week over an eight-week study period. Pre- and post-training assessments included one repetition maximum (1RM) testing in the full ROM (0°-135°), and measurement of biceps brachii cross-sectional area (CSA) at 50% and 70% of humerus length. Paired t-tests were used to compare regional CSA changes between groups, the sum of CSA changes at 50% and 70% (CSAsummed), and the strength response between the training protocols. RESULTS: The INITIALROM protocol displayed a greater CSA increase than FINALROM protocol at 70% of biceps length (p = 0.001). Alternatively, we observed similar increases between the protocols for CSA at 50% (p = 0.311) and for CSAsummed (p = 0.111). Moreover, the INITIALROM protocol displayed a greater 1RM increase than FINALROM (p < 0.001). CONCLUSIONS: We conclude that training in the initial angles of elbow flexion exercise promotes greater distal hypertrophy of the biceps brachii muscle in untrained young women. Moreover, the INITIALROM condition promotes a greater dynamic strength increase when tested at a full ROM compared to the FINALROM.

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Creatine supplementation has been shown to increase measures of lean body mass (LBM); however, there often is high heterogeneity across individual studies. Therefore, the aim of this study was to systematically review and meta-analyze randomized controlled trials (RCTs) investigating creatine supplementation on LBM. Subanalyses were performed based on age, sex, and type of exercise. Based on PRISMA guidelines, we searched the following databases: Pubmed, SPORTDiscus, Web of Science, and Scopus (PROSPERO register: CRD42020207122) until May 2022. RCTs for investigation of creatine supplementation on LBM were included. Animal studies and studies on individuals with specific diseases were excluded. Thirty-five studies were included, with 1192 participants. Overall (i.e., inclusion of all studies with and without exercise training interventions) revealed that creatine increased LBM by 0.68 kg (95% confidence interval [CI], 0.26-1.11). Subanalyses revealed greater gains in LBM when creatine was combined with resistance training (mean difference [MD], 1.10 kg; 95% CI, 0.56-1.65), regardless of age. There was no statistically significant effect of creatine on LBM when combined with mixed exercise (MD, 0.74 kg; 95% CI, -3.89 to 5.36) or without exercise (MD, 0.03 kg; 95% CI, -0.65 to 0.70). Further subanalyses found that males on creatine increased LBM by 1.46 kg (95% CI, 0.47-2.46), compared with a non-significant increase of 0.29 kg (95% CI, -0.43 to 1.01) for females. In conclusion, the addition of creatine supplementation to a resistance training program increases LBM. During a resistance training program, males on creatine respond more favorably than females.

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Low-intensity aerobic training combined with blood flow restriction (LI + BFR) has resulted in increases in aerobic and neuromuscular capacities in untrained individuals. This strategy may help cyclists incapable of training with high intensity bouts or during a rehabilitation program. However, there is a lack of evidence about the use of LI + BFR in injured trained cyclists. Thus, we investigated the effects of LI + BFR on aerobic capacity, maximal isometric strength, cross-sectional area of vastus lateralis (CSAVL), time to exhaustion test (TTE), and 20 km cycling time-trial performance (TT20 km) in a male cyclist with knee osteoarthritis (OA). After a 4-week control period, a 9-week (2 days/week) intervention period started. Pre- and post-intervention TT20 km, peak oxygen consumption (VO2peak), power output of the 1st and 2nd ventilatory thresholds (1st WVT and 2nd WVT), maximum power output (Wmax), TTE, muscle strength and CSAVL of both legs were measured. Training intensity was fixed at 30% of Wmax while the duration was progressively increased from 12 min to 24 min. There was a reduction in time to complete TT20 km (-1%) with increases in TT20 km mean power output (3.9%), VO2peak (11.4%), 2nd WVT (8.3%), Wmax (3.8%), TTE (15.5%), right and left legs maximal strength (1.3% and 8.5%, respectively) and CSAVL (3.3% and 3.7%, respectively). There was no alteration in 1st WVT. Based on the results, we suggest that LI + BFR may be a promising training strategy to improve the performance of knee-injured cyclists with knee OA.

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We compared the magnitude of strength and muscle mass changes in response to resistance training (RT) between stronger older women and their weaker counterparts. Older women (n = 207) were grouped into tertiles according to their baseline muscular strength index. The upper and lower tertiles participants were categorized as stronger (STR, n = 69) and weaker (WKR, n = 69), respectively. Both groups engaged in a 12-week whole-body RT program. Outcomes included one-repetition maximum (1RM) tests in the three lifts and assessment of segmental lean soft tissue (LST) and skeletal muscle mass (SMM). The 1RM increase was similar between groups for the chest press [between-groups effect size of the differences (ESdiff) and 95% confidence interval (95%CI) = 0.10 (95%CI: -0.52, 0.31), P = 0.617] and preacher curl [ESdiff = 0.08 (95%CI: -0.48, 0.32), P = 0.681]. Changes were greater in WKR than STR for 1RM leg extension [ESdiff = -0.45 (95%CI: -0.86, -0.04), P = 0.030]. The increases of segmental LST and SMM were similar between-groups (ESdiff contains zero, P ≥ 0.434). We conclude that stronger and weaker older women benefit similarly for muscle mass and upper-limb strength gains. Notably, weaker older women may experience greater lower-limbs strength gains.

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The study compared changes in strength and regional muscle hypertrophy between different ranges of motion (ROM) in the knee extension exercise. Forty-five untrained women were randomized to either a control group or to perform the exercise in one of the following 4 groups (0°=extended knee): Full ROM (FULLROM: 100°-30° of knee flexion); Initial Partial ROM (INITIALROM: 100°-65°); Final Partial ROM (FINALROM: 65°-30°); Varied ROM (VARROM: daily alternation between the ROM of INITIALROM and FINALROM). Pre- and post-training assessments included one repetition maximum (1RM) testing in the ROM corresponding to the initial, final and full ROM, and measurement of cross-sectional areas of the rectus femoris and vastus lateralis muscles at 40%, 50%, 60% and 70% of femur length in regard to regional muscle hypertrophy. Results showed that the INITIALROM group presented a greater relative increase than all groups at 70%, and at 50% and 60% the increases were greater than FINALROM, FULLROM, and non-training control (CON) groups. Moreover, FINALROM group presented similar changes compared to the CON group at 60% and 70%. In regard to 1RM, FINALROM and INITIALROM groups presented greater relative increases at the ROM trained, and no group showed greater increases than VARROM or INITIALROM, regardless the ROM tested. In conclusion, partial ROM training in the initial phase of the knee extension exercise promoted greater relative hypertrophy in certain muscle regions than training in other ROM configurations, and no group promoted a greater 1RM increase than VARROM group, which showed similar 1RM increases in the different ROMs tested.

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Muscle atrophy is a great consequence of spinal cord injuries (SCI) due to immobility. SCI's detrimental effects on large muscle groups may lead to secondary effects such as glucose intolerance, increased risk of metabolic syndrome, and diabetes. Exercising with blood flow restriction (BFR) has been proposed as an effective method to induce hypertrophy using low training loads, with little or no muscle damage. This study investigated acute and chronic effects of low-intensity functional electrical stimulation (FES) combined with BFR on muscles affected by spinal cord injury. The acute effects of one bout of FES with (FES + BFR group) and without BFR (FES group) on muscle thickness (MT) and edema formation were compared. The chronic effects on MT and edema following 8 weeks of twice weekly training with and without BFR were also compared. The FES + BFR group showed MT and edema increases compared to the FES only group (p< 0.05). The FES + BFR showed a chronic MT increase after 4 weeks of training (p <0.05), with no further MT increases from the 4th to the 8th week (p>0.05). Following 3 weeks of detraining, MT decreased to baseline. No MT changes were observed in the FES (p>0.05). The FES + BF stimuli induced MT increases on the paralyzed skeletal muscles of SCI. The acute effects suggest that FES causes a greater metabolite accumulation and edema when combined with BFR. The early increases in MT can be attributed to edema, whereas after the 4th week, it is likely to be related to muscle hypertrophy. Register Clinical Trial Number on ReBeC: RBR-386rm8.

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Whole egg may have potential benefits for enhancing muscle mass, independent of its protein content. The yolk comprises ∼40% of the total protein in an egg, as well as containing several nonprotein nutrients that could possess anabolic properties (e.g., microRNAs, vitamins, minerals, lipids, phosphatidic acid and other phospholipids). Therefore, the purpose of this narrative review is to discuss the current evidence as to the possible effects of egg yolk compounds on skeletal muscle accretion beyond those of egg whites alone. The intake of whole egg seems to promote greater myofibrillar protein synthesis than egg white intake in young men. However, limited evidence shows no difference in muscle hypertrophy when comparing the consumption of whole egg versus an isonitrogenous quantity of egg white in young men performing resistance training. Although egg yolk intake seems to promote additional acute increases on myofibrillar protein synthesis, it does not seem to further enhance muscle mass when compared to egg whites when consumed as part of a high-protein dietary patterns, at least in young men. This conclusion is based on very limited evidence and more studies are needed to evaluate the effects of egg yolk (or whole eggs) intake on muscle mass not only in young men, but also in other populations such as women, older adults, and individuals with muscle wasting diseases.

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This paper aimed to compare the effect of drop-set (DS) and rest-pause (RP) systems versus traditional resistance training (TRT) with equalized total training volume on maximum dynamic strength (1RM) and thigh muscle thickness (MT). Twenty-eight resistance-trained males were randomly assigned to either RP (n = 10), DS (n = 9) or TRT (n = 9) protocols performed twice a week for 8 weeks. 1RM and MT of the proximal, middle and distal portions of the lateral thigh were assessed at baseline and post-intervention. A significant time × group interaction was observed for 1RM (P = 0.001) in the barbell back squat after 8-weeks. Post hoc comparisons revealed that RP promoted higher 1RM than TRT (P = 0.001); no statistical differences in strength were observed between the other conditions. A significant main effect of time was revealed for MT at the proximal (P = 0.0001) and middle (P = 0.0001) aspects of the lateral thigh for all training groups; however, the distal portion did not show a time effect (P = 0.190). There were no between-group interactions for MT. Our findings suggest that RP promotes slightly superior strength-related improvements compared with TRT, but hypertrophic adaptations are similar between conditions. Novelty: Rest-pause elicited a slightly superior benefit for strength adaptations compared with traditional resistance training. Resistance training systems do not promote superior hypertrophic adaptations when total training volume is equalized. Muscle thickness in distal portion of thigh is similar to baseline. Although modest, effect sizes tended to favor rest-pause.

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Resumen: La amiloidosis engloba distintas enfermedades caracterizadas por el depósito extracelular de una proteína anómala e insoluble (amiloide) en los diferentes tejidos, causando su disfunción progresiva. La presentación clínica suele ser heterogénea, lo que determina el diagnóstico tardío. Para alcanzarlo se requiere de biopsia del tejido afectado, la demostración del depósito amiloide y la tipificación de la proteína que lo constituye. La detección precoz permite optimizar el tratamiento, condicionando esto el pronóstico. La miopatía amiloide asociada a una discrasia de células plasmáticas es una causa infrecuente de hipertrofia muscular; por lo que en el siguiente artículo se busca presentar un caso clínico de la misma con posterior revisión de la literatura.

Abstract: Amyloidosis encompasses various diseases characterized by the extracellular deposition of an abnormal and insoluble (amyloid) protein among the different tissues, causing its progressive dysfunction. The clinical presentation is usually heterogeneous, which determines the delays in diagnosis. To achieve this, a biopsy of the affected tissue, the demonstration of amyloid deposit and the typing of the protein that constitutes it are required. Early detection allows optimizing the treatment, conditioning the prognosis. Amyloid myopathy associated with plasma cell dyscrasia is an infrequent cause of muscle hypertrophy, for which reason the following article seeks to present a clinical case of it with a subsequent review of the literature.

Resumo: A amiloidose engloba diferentes doenças caracterizadas pela deposição extracelular de uma proteína anormal e insolúvel (amiloide) em diferentes tecidos, causando sua disfunção progressiva. A apresentação clínica costuma ser heterogênea, o que determina o diagnóstico tardio. Para tanto, é necessária a biópsia do tecido afetado, a demonstração do depósito amilóide e a tipagem da proteína que o constitui. A detecção precoce permite otimizar o tratamento, condicionando o prognóstico. A miopatia amilóide associada à discrasia das células plasmáticas é uma causa rara de hipertrofia muscular; Portanto, o seguinte artigo busca apresentar um caso clínico desta com posterior revisão da literatura.

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External load influences internal load in resistance training (RT). The purpose of the present study was to compare the total volume-load, perceptual and stress responses during three different RT protocols. Twelve resistance-trained men completed three different RT protocols with the back squat and bench press exercises: (1) power (POW) (5 sets of 6 repetitions at 50%1RM, 2-min of rest), (2) hypertrophy (HYP) (5 sets-to-failure at 75%1RM, 2-min of rest), and (3) strength (STR) (5 sets-to-failure at 90%1RM, 3-min of rest). Volume-load (kg × reps.), session rating of perceived exertion (sRPE), training impulse (TRIMP; reps. × sRPE), cortisol, immunoglobulin A (IgA), lactate, and creatine kinase (CK) were assessed before and/or after the sessions. HYP was the most demanding session in terms of volume-load (p < 0.001), TRIMP (p < 0.001), cortisol (p = 0.001), lactate (p < 0.001), and CK (p = 0.001). Despite POW exhibited a greater volume-load than STR (p = 0.016), the latter exhibiting a greater sRPE (p < 0.001), and a greater post-session CK (p = 0.05). However, the TRIMP of STR and POW were not statistically different (152 vs. 260 AU; p = 0.089). These specific responses could be meditated by the presence of muscular failure. When pooling all the sessions, significant correlations were revealed among external and internal stress markers (r = 0.35-0.80; p ≤ 0.05). The use of TRIMP could be recommended as a simple and valid monitoring tool which integrates into a single parameter the internal and the external loads of RT sessions.

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Although used by resistance-trained individuals, it is unknown if increasing muscle strength prior to hypertrophy training leads to greater muscle growth and strength gains. We investigated muscle thickness and maximum strength in 26 resistance-trained men who were randomly assigned to either: STHT, consisted in a 3-week strength-oriented training period (4x1-3 repetition maximum [RM]) prior to a 5-week hypertrophy-oriented period (4x8-12RM), or HT, which comprised an 8-week hypertrophy-oriented training period. Vastus lateralis muscle thickness, and back squat and leg-press 1-RM were assessed at pre, third week, and after 8 weeks of training. When pre-to-post changes are compared, STHT induced greater muscle growth (p = 0.049; 95%CI = 0.15-3.2%; d = 0.81) and strength gains in the back squat (p = 0.015; 95%CI = 1.5-13%; d = 1.05) and leg-press 45° (p = 0.044; 95%CI = 0.16-9.9%; d = 0.79) compared to HT. Our results support the use of a period to increase muscle strength prior to an HT to increase muscle thickness and maximum strength in resistance-trained men.

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