Systematic physical activity increases physical fitness and exercise capacity that lead to the improvement of health status and athletic performance. Considerable effort is devoted to identifying new biomarkers capable of evaluating exercise performance capacity and progress in training, early detection of overtraining, and monitoring health-related adaptation changes. Recent advances in OMICS technologies have opened new opportunities in the detection of genetic, epigenetic and transcriptomic biomarkers. Very promising are mainly small non-coding microRNAs (miRNAs). miRNAs post-transcriptionally regulate gene expression by binding to mRNA and causing its degradation or inhibiting translation. A growing body of evidence suggests that miRNAs affect many processes and play a crucial role not only in cell differentiation, proliferation and apoptosis, but also affect extracellular matrix composition and maintaining processes of homeostasis. A number of studies have shown changes in distribution profiles of circulating miRNAs (c-miRNAs) associated with various diseases and disorders as well as in samples taken under physiological conditions such as pregnancy or physical exercise. This overview aims to summarize the current knowledge related to the response of blood c-miRNAs profiles to different modes of exercise and to highlight their potential application as a novel class of biomarkers of physical performance capacity and training adaptation.

It has been clearly established that maximal force and power is lower in the morning compared to noon or afternoon hours. This morning neuromuscular deficit can be diminished by regularly training in the morning hours. However, there is limited and contradictory information upon hypertrophic adaptations to time-of-day-specific resistance training. Moreover, no cellular or molecular mechanisms related to muscle hypertrophy adaptation have been studied with this respect. Therefore, the present study examined effects of the time-of-day-specific resistance training on muscle hypertrophy, phosphorylation of selected proteins, hormonal concentrations and neuromuscular performance. Twenty five previously untrained males were randomly divided into a morning group (n = 11, age 23 ± 2 yrs), afternoon group (n = 7, 24 ± 4 yrs) and control group (n = 7, 24 ± 3 yrs). Both the morning and afternoon group underwent hypertrophy-type of resistance training with 22 training sessions over an 11-week period performed between 07:30-08:30 h and 16:00-17:00 h, respectively. Isometric MVC was tested before and immediately after an acute loading exclusively during their training times before and after the training period. Before acute loadings, resting blood samples were drawn and analysed for plasma testosterone and cortisol. At each testing occasion, muscle biopsies from m. vastus lateralis were obtained before and 60 min after the acute loading. Muscle specimens were analysed for muscle fibre cross-sectional areas (CSA) and for phosphorylated p70S6K, rpS6, p38MAPK, Erk1/2, and eEF2. In addition, the right quadriceps femoris was scanned with MRI before and after the training period. The control group underwent the same testing, except for MRI, between 11:00 h and 13:00 h but did not train. Voluntary muscle strength increased significantly in both the morning and afternoon training group by 16.9% and 15.2 %, respectively. Also muscle hypertrophy occurred by 8.8% and 11.9% (MRI, p < 0.001) and at muscle fibre CSA level by 21% and 18% (p < 0.01) in the morning and afternoon group, respectively. No significant changes were found in controls within these parameters. Both pre- and post-training acute loadings induced a significant (p < 0.001) reduction in muscle strength in all groups, not affected by time of day or training. The post-loading phosphorylation of p70S6Thr421/Ser424 increased independent of the time of day in the pre-training condition, whereas it was significantly increased in the morning group only after the training period (p < 0.05). Phosphorylation of rpS6 and p38MAPK increased acutely both before and after training in a time-of-day independent manner (p < 0.05 at all occasions). Phosphorylation of p70S6Thr389, eEF2 and Erk1/2 did not change at any time point. No statistically significant correlations were found between changes in muscle fibre CSA, MRI and cell signalling data. Resting testosterone was not statistically different among groups at any time point. Resting cortisol declined significantly from pre- to post-trai...

The randomized trials showed that the addition of training resistance program to androgen-deprivation therapy (ADT) had many beneficial effects for prostate cancer (PC) patients (significant protective effect on the volume of muscle mass) and the studies have revealed a panel of miRNAs, which are deregulate in PC and may serve as promising biomarkers of PC risk. The primary aim of our present study was to investigate the effect of exercise training to changes in body composition (muscle strength) and the secondary endpoint was to investigate the impact of an exercise training program on plasma levels of selected myogenic microRNAs (miRNAs) (miRNA-1, miRNA-29b, and miRNA-133) in PC patients undergoing the ADT. Effect of ADT and exercise intervention showed significant increase (experimental group vs. control group) the changes in body composition, free testosterone levels, IL-6 and plasma levels of myogenic miRNAs and significant reduced insulin serum levels. In conclusion, resistance training with ADT in the treatment of PC significantly changed the physical and metabolic function and the plasma levels of specific myogenic miRNAs. Our data support with the other publicized results.

. (2013). Effects of time of day on resistance exerciseinduced anabolic signaling in skeletal muscle. Biological rhythm research, 44, s. 756-770. Dette er siste tekst-versjon av artikkelen, og den kan inneholde små forskjeller fra forlagets pdf-versjon. Forlagets pdf-versjon finner du på www.tandfonline.com: http://dx.doi.org/10. 1080/09291016.2012.740314 This is the final text version of the article, and it may contain minor differences from the journal's pdf version. The original publication is available at www.tandfonline.com: http://dx.doi.org/10. 1080/09291016.2012.740314 Effects of time of day on resistance exercise-induced anabolic signalling in skeletal muscle IntroductionTime of day has been shown to affect various indices related to neuromuscular performance in both acute responses to a bout of resistance exercise and long-term adaptations to resistance training. For instance, muscle strength is typically lower in the morning compared to the afternoon (for a review see (10)). However, lower neuromuscular performance in the morning can be improved to the afternoon levels by regularly training in the morning hours over the period of several weeks (34,35).Whether the hypertrophic adaptation of skeletal muscle to resistance training also is affected by the time-of-day-specific training, is less studied. To our best knowledge, the only study performed on humans found a tendency to smaller gains in muscle size when repeatedly training in the morning compared to the late afternoon hours (36). Although statistically insignificant, subjects training in the afternoon hours increased their m.quadriceps femoris volume, measured by magnetic resonance imaging, on average 30% more compared to their counterparts in the morning training group (36). One of the possible mechanisms contributing to the above-mentioned time-of-day-dependent training adaptations is signalling pathways involved in the control of protein synthesis and protein degradation.In general, muscle hypertrophy/atrophy is a net result of an increase in protein synthesis minus protein degradation. A single bout of resistance exercise is a potent stimulus for increasing the post-exercise rate of protein synthesis per se, both in the acute recovery phase and lasting up to 48 hours (24,29). Phosphorylation of specific proteins in protein kinase B/muscle target of rapamycin/p70 ribosomal S6 kinase signalling pathway (Akt/mTOR/p70S6K) and to some extent also in mitogen-activated protein kinases (MAPK) signalling pathway has been shown to positively regulate muscle growth (2,37,40). Further, resistance exercise primarily aimed at increasing muscle hypertrophy is a potent stimulus to increase mTOR and MAPK signalling (9,18,19,40). At least signalling through rapamycin sensitive mTOR complex 1 (mTORC1) is needed to induce protein synthesis after resistance exercise (9). However, there are very limited data available addressing whether and how the activation of these signalling pathways can be influenced by a single bout of exercise or repeated resistan...

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