The aim of this study was to compare if an acute exercise session of high-load resistance training (HL-RT, e.g. 70% of 1 repetition-maximum, 1 RM) induces a higher magnitude of muscle damage compared with a RT protocol with low-loads (e.g. 20% 1 RM) associated with partial blood flow restriction (LL-BFR), and investigate the recovery in the days after the protocols. We used an unilateral crossover research design in which 10 young women (22(2) y; 162(5) cm; 66(11) kg) performed HL-RT and LL-BFR in a randomized, counterbalanced manner with a minimum interval of 2 weeks between protocols. Indirect muscle damage markers were evaluated before and once a day for 4 days into recovery. Main results showed decreases of 8-12% at 24-48 h in maximal voluntary isometric and concentric contraction torques (P < 0.03), and changes in muscle architecture markers (P < 0.03) for HL-RT and LL-BFR, with no differences between protocols (P > 0.05). Moreover, delayed onset muscle soreness increased only after LL-BFR (P < 0.001). We conclude that an acute bout of low volume HL-RT or LL-BFR to failure resulted in edema-induced muscle swelling, but do not induce major or long-lasting decrements in muscle function and the level of soreness promoted from LL-BFR was mild.

The aim of this study was to compare the effect of self-selected repetition duration (SELF), with and without volume load (VL) equalized with controlled repetition duration (CON) on muscle strength and hypertrophy in untrained males. We used a within-subjects design in which 20 volunteers (age: 24.7 ± 2.9 years) had one leg randomly assigned to CON (i.e., 2 s concentric, 2 s eccentric) and the other to SELF or to self-selected repetition duration with equalized volume load (SELF-EV). One repetition maximum (1-RM) and muscle cross-sectional area (CSA) were measured at baseline (Pre) and after (Post) resistance training (RT; 2Â/wk for 8 weeks). For the main study variables (1-RM and muscle CSA), a mixed-model analysis was performed, assuming repetition duration (SELF, SELF-EV and CON), and time (Pre and Post) as fixed factors and the subjects as random factor for each dependent variable (1-RM and CSA). All RT protocols showed significant increases in values of 1-RM from Pre (CON: 73.7 ± 17.6 kg; SELF: 75.9 ± 17.7 kg; and SELF-EV: 72.6 ± 16.9 kg) to Post (CON: 83.4 ± 19.9 kg, effect size (ES): 0.47; SELF: 84 ± 19.1 kg, ES: 0.43; and SELF-EV: 83.2 ± 19.9 kg, ES: 0.57, P < 0.0001). Muscle CSA values increased for all protocols from Pre (CON: 12.09 ± 3.14 cm 2 ; SELF: 11.91 ± 3.71 cm 2 ; and SELF-EV: 11.93 ± 2.32 cm 2 ) to Post (CON: 13.03 ± 3.25 cm 2 , ES: 0.29; SELF: 13.2 ± 4.16 cm 2 , ES: 0.32; and SELF-EV: 13.2 ± 2.35 cm 2 , ES: 0.53, P < 0.0001). No significant differences between protocols were found for both 1-RM and CSA (P > 0.05). Performing RT with SELF, regardless of VL, was equally effective in inducing increases in muscle strength and hypertrophy compared to CON in untrained men. Subjects Anatomy and Physiology, KinesiologyHow to cite this article Chaves TS, Pires de Campos Biazon TM, Marcelino Eder dos Santos L, Libardi CA. 2020. Effects of resistance training with controlled versus self-selected repetition duration on muscle mass and strength in untrained men. PeerJ 8:e8697 Schoenfeld BJ, Ogborn DI, Krieger JW. 2015. Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine 45(4):577-585 DOI 10.1007/s40279-015-0304-0.Schoenfeld BJ, Ogborn D, Krieger JW. 2017. Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis.

Background and aimSepsis is associated with marked alterations in hemodynamic responses, autonomic dysfunction and impaired vascular function. However, to our knowledge, analysis of noninvasive markers to identify greater risk of death has not yet been investigated. Thus, our aim was to explore the prognostic utility of cardiac output (CO), stroke volume (SV), indices of vagal modulation (RMSSD and SD1), total heart rate variability (HRV) indices and FMD of brachial artery (%FMD), all measured noninvasively, in the first 24 hours of the diagnosis of sepsis.Methods60 patients were recruited at ICU between 2015 and 2017 and followed by 28 days. CO, SV, RR intervals were measurement. Doppler ultrasound was used to assess brachial artery FMD and the hyperemic response were obtained (%FMD). Patients were divided by survivors (SG) and nonsurvivors groups (NSG).ResultsA total of 60 patients were analysed (SG = 21 and NSG = 39). Survivors were younger (41±15 years vs. 55±11 years) and used less vasoactive drugs. As expected, APACHE and SOFA scores were lower in NSG compared to SG. In addition, higher SD1, triangular index, % FMD, velocity baseline and hyperemia flow velocity as well as lower HR values were observed in the SG, compared to NSG (P<0.05). Interestingly, RMSSD and SD1 indices were independent predictors of %FMD, ΔFMD and FMDpeak. RMSSD threshold of 10.8ms and %FMD threshold of -1 were optimal at discriminatomg survivors and nonsurvivors.ConclusionNoninvasive measurements of autonomic and endotelial function may be important markers of sepsis mortality, which can be easily obtained in the early stages of sepsis at the bedside.

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Background Intensive care unit-acquired atrophy and weakness are associated with high mortality, a reduction in physical function, and quality of life. Passive mobilization (PM) and neuromuscular electrical stimulation were applied in comatose patients; however, evidence is inconclusive regarding atrophy and weakness prevention. Blood flow restriction (BFR) associated with PM (BFRp) or with electrical stimulation (BFRpE) was able to reduce atrophy and increase muscle mass in spinal cord-injured patients, respectively. Bulky venous return occurs after releasing BFR, which can cause unknown repercussions on the cardiovascular system. Hence, the aim of this study was to investigate the effect of BFRp and BFRpE on cardiovascular safety and applicability, neuromuscular adaptations, physical function, and quality of life in comatose patients in intensive care units (ICUs). Methods Thirty-nine patients will be assessed at baseline (T0–18 h of coma) and randomly assigned to the PM (control group), BFRp, or BFRpE groups. The training protocol will be applied in both legs alternately, twice a day with a 4-h interval until coma awake, death, or ICU discharge. Cardiovascular safety and applicability will be evaluated at the first training session (T1). At T0 and 12 h after the last session (T2), muscle thickness and quality will be assessed. Global muscle strength and physical function will be assessed 12 h after T2 and ICU and hospital discharge for those who wake up from coma. Six and 12 months after hospital discharge, physical function and quality of life will be re-assessed. Discussion In view of applicability, the data will be used to inform the design and sample size of a prospective trial to clarify the effect of BFRpE on preventing muscle atrophy and weakness and to exert the greatest beneficial effects on physical function and quality of life compared to BFRp in comatose patients in the ICU. Trial registration Universal Trial Number (UTN) Registry UTN U1111-1241-4344. Retrospectively registered on 2 October 2019. Brazilian Clinical Trials Registry (ReBec) RBR-2qpyxf. Retrospectively registered on 21 January 2020, http://ensaiosclinicos.gov.br/rg/RBR-2qpyxf/