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Purpose: It has been suggested that flexibility training may reduce the total volume of training during resistance trainings. The purpose of this study was to compare the effect of flexibility training immediately before resistance training (FLEX-RT) versus resistance training without flexibility training (RT) on maximum strength and the vastus lateralis muscle cross-sectional area (CSA)., Methods: Participants had each leg assigned to RT or FLEX-RT. Both groups performed four sets of leg extensions to voluntary failure of 80% of one repetition maximum (1RM); however, FLEX-RT performed two sets of 25 s of static stretching before resistance training. Number of repetitions and total volume were calculated during weeks 1-5 and 6-10. Vastus lateralis muscle CSA, 1RM, and flexibility were assessed at baseline and after 10 weeks., Results: The number of repetitions and total training volume were greater for RT than FLEX-RT for weeks 1-5 and 6-10. Regarding the vastus lateralis muscle CSA, a main time effect was observed, however, greater change was observed for RT than FLEX-RT (12.7 and 7.4%, respectively). A main time effect for 1RM was also observed with similar changes for RT and FLEX-RT (12.7 and 12.9%, respectively). Flexibility was increased pre- to post-training for FLEX-RT with greater change for FLEX-RT (10.1%) than RT (2.1%)., Conclusion: These results show that performing flexibility training immediately before resistance training can contribute to a lower number of repetitions, total volume, and muscle hypertrophy.

Purpose: Autophagy is an intracellular degradative system sensitive to hypoxia and exercise-induced perturbations to cellular bioenergetics. We determined the effects of low-intensity endurance-based exercise performed with blood-flow restriction (BFR) on cell signaling adaptive responses regulating autophagy and substrate metabolism in human skeletal muscle., Methods: In a randomized cross-over design, nine young, healthy but physically inactive males completed three experimental trials separated by 1 week of recovery consisting of either a resistance exercise bout (REX: 4 × 10 leg press repetitions, 70% 1-RM), endurance exercise (END: 30 min cycling, 70% VO 2peak ), or low-intensity cycling with BFR (15 min, 40% VO 2peak ). A resting muscle biopsy was obtained from the vastus lateralis 2 weeks prior to the first exercise trial and 3 h after each exercise bout., Results: END increased ULK1 Ser757 phosphorylation above rest and BFR (~37 to 51%, P < 0.05). Following REX, there were significant elevations compared to rest (~348%) and BFR (~973%) for p38γ MAPK Thr180/Tyr182 phosphorylation (P < 0.05). Parkin content was lower following BFR cycling compared to REX (~20%, P < 0.05). There were no exercise-induced changes in select markers of autophagy following BFR. Genes implicated in substrate metabolism (HK2 and PDK4) were increased above rest (~143 to 338%) and BFR cycling (~212 to 517%) with END (P < 0.001)., Conclusion: A single bout of low-intensity cycling with BFR is insufficient to induce intracellular "stress" responses (e.g., high rates of substrate turnover and local hypoxia) necessary to activate skeletal muscle autophagy signaling.

The present study aimed to analyze the magnitude of muscle damage and inflammatory responses induced by eccentric exercise in young (YW) and postmenopausal women (PMW). Seventeen healthy women (nine YW, 23.89 ± 2.03 years; and eight PMW, 51.13 ± 5.08 years) performed five sets of six maximal eccentric actions of the elbow flexors. Changes in isometric strength, range of motion, muscle soreness, and upper-arm circumference were evaluated pre, post, 24, 48, and 72 h following eccentric exercise. Changes in creatine kinase activity, interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor-α (TNF-α), and prostaglandin E(2) (PGE(2)) were measured pre, 24, 48, and 72 h following eccentric exercise. For intra and inter-group analysis, a two-way repeated measures ANOVA was applied followed by a Tukey's post hoc test. Pearson's correlation was used to analyze the correlations between variables. It was observed no differences between groups for the markers of muscle damage, although significant modifications (p < 0.05) occurred within groups throughout time for all variables. Post menopausal women showed significantly higher values for TNF-α (p < 0.05). Also, IL-6 presented superior pre value for PMW. For YW, IL-6 and IL-10 values increased 72 h post-eccentric exercise compared to pre. Further, IL-10 was higher for YW than PMW 72 h post-eccentric exercise. Significant correlations (p < 0.05) were found between age and soreness, and between age and PGE(2). In conclusion, YW do not have attenuated muscle damage compared to PMW who do not make use of hormonal replacement therapy. In addition, YW have a greater anti-inflammatory response after eccentric exercise compared to PMW.