Background: Intradialytic resistance training (IRT) protects patients’ muscle mass and functions against protein-energy wasting, malnutrition and cachexia. However, the evidence of the effects of such an intervention in haemodialysis patients is limited and not conclusive. To improve the applicability of such interventions, we need a better understanding of molecular, functional and psycho-social adaptation in dialysed patients following a physical training. Therefore, the aim of this study is to investigate the effects of IRT on lower extremity muscle functions, quality of life, and anxiety and depression, clinical outcomes and circulatory micro-ribonucleic acid (miRNA) profiles in patients on chronic haemodialysis therapy. Methods: We will perform a quasi-experimental study in 3 dialysis centres. Patients will be recruited via their nephrologists and will be allocated to an experimental and a control group based on the location of the patients’ dialysis centre. Patients allocated to the experimental group will undergo a 12-week IRT, while the control group will remain physically inactive during dialysis. The primary outcome is the change in the maximal force produced during an isometric contraction of lower extremity muscles. Secondary outcomes regard quality of life, anxiety and depression, clinical outcomes and circulatory miRNA profiles. Patients’ level of health literacy defined as the ability to get and understand health information will be also measured in the study as a potential modifier of effects. Discussion: This quasi-experimental study can add in an important way to our understanding of the effects of resistance training on dialysis patients’ muscle strength, quality of life and disease-specific outcomes.

. (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...

The miRNA-206 and miRNA-23a play an important role in muscle tissue hypertrophy, regeneration and atrophy. Both of these miRNAs have been highlighted as promising adaptation predictors; however, the available evidence on associations is inconclusive. Therefore, our aim was to assess the expression levels of these two miRNAs as predictors of change in muscle function during strength training and physical inactivity among dialysed patients. For this purpose, 46 haemodialysis patients were monitored for 12-weeks of either intradialytic strength training (EXG, n = 20) or physical inactivity during dialysis (CON, n = 26). In both groups of patients, we assessed the baseline expression levels of miRNA-23a and miRNA-206 and the isometric force generated during hip flexion (HF) contraction before and after the 12-week period. Among the EXG group, the expression of miRNA-206 predicted the change in HF (R2 = 0.63, p = 0.0005) much more strongly than the expression of miRNA-23a (R2 = 0.21, p = 0.027). Interestingly, baseline miRNA-23a (R2 = 0.30, p = 0.006) predicted the change in HF much more than miRNA-206 (p = ns) among the CON group. Our study indicates that the baseline expression of miRNA-206 could predict the response to strength training, while miRNA-23a could serve as a potential predictive marker of functional changes during physical inactivity in dialysis patients.

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