“…The structural validity was 'inadequate'. As a result, an exploratory factorial analysis was carried out, and three factors were identified by means of the Scree test: 'physical subscale' (the first subscale consisted of seven items that were related to the physical sensations of fatigue; easily tired, having urge to lie down, exhausted, heavy and tired, fed-up, reluctant and fatigue you do not know what to do with yourself), 'affective subscale' (the second subscale consisted of four items that assessed affective activity; energetic feeling, interest in something, ability to concentrate and encourage yourself to do something) and 'cognitive subscale' (the third subscale consisted of four items that assessed attention and memory; careless, instrument included in the largest number of studies, 14 in total (Alawneh et al, 2016;Arraras et al, 2014;Golči c et al, 2018;Groenvold et al, 2006;Leppert & Majkowicz, 2013;Miyashita et al, 2015;Miyazaki et al, 2012;Nunes, 2014;Ozcelik et al, 2016;Raman et al, 2016;Rojas-Concha et al, 2020;Shin et al, 2011;Suárez-del-Real et al, 2011;Zhang et al, 2016) and for which more psychometric properties were measured: content validity, structural validity, internal consistency, cross-cultural validity, reliability, criterion validity, hypotheses testing and responsiveness (all except for measurement error). The content validity was classified as 'inadequate'…”