Irisin seems to play an important role in several chronic diseases, however, the interactions between chronic training and irisin are still unclear. The purpose of this systematic review and meta-analysis was to examine the effect of chronic resistance training on circulating irisin in adults. Literature search was conducted in PubMed, Web of Science and EBSCOhost (Academic Search Complete) until December 2020. Randomized controlled trials researching irisin levels after a resistance training program for at least 8 weeks among an adult population were eligible. Other inclusion criteria comprised recruiting a control group and reporting circulating irisin through ELISA kits. Cohen’s d effect size and subgroup analyses (95% confidence level) were calculated using a random effects analysis model. Data of the seven included studies comprising 282 individuals showed an increasing and non-significant tendency after a resistance training program (d = 0.58, 95% CI: −0.25 to 1.40, p = 0.17). Subgroup analyses showed significant increases for the older adults group (p < 0.001) and when training is demanding and progressive in terms of intensity (p = 0.03). Data suggest that resistance training programs seem to increase circulating irisin, especially in older adults and in demanding and progressive training programs. However, more studies should be conducted using robust measurement methods, such as mass spectrometry, to better understand the interaction between chronic resistance exercise and irisin.

The articular evaluation of range of motion (ROM) is currently used to observe imbalance or limitations as possible risk factors or predispositions to suffer future injures. The main aim of this study is to verify the concurrent validity, reliability and reproducibility of the OctoBalance Test (OB) as a valid and reliable tool to measure articular ROM of the upper limb compared to the modified-Upper Quarter Y-Balance Test (mUQYBT). The twenty-five participants were male athletes. All of them were assessed with OB and mUQYBT in medial, superolateral, and inferolateral directions in both right and left arms with a three-minute break during these attempts. The process was repeated a second time with a week gap between measurements. Pearson correlation and linear logarithmic regression were used to examine the relationship between scores obtained with OB and mUQYBT. In order to verify the reliability, the intraclass correlation coefficient (ICC) was used (3.1). Concordance and reproducibility were assessed using Bland–Altman’s graph. A perfect correlation and an almost linear logarithmic regression (R2 = 0.97) were observed between both measurement systems, with values of 73.531 ± 21.226 cm in mUQYBT and 69.541 ± 16.330 cm in OB. The differences were minimal between week one and week two. The assessment with Bland’s graph showed the concordance and reproducibility of scores, showing the dispersion and the upper and lower limits. OB is shown as valid in comparison to the other test as a reliable and reproducible tool for the assessment of the articular ROM in the upper limb, and it could be used for the evaluation of injuries.