The prevalence of iron deficiency in male athletes in previous studies ranged from 2.9 to 31.0%, [28,29,54,55,56,57,58,59,60], although the comparison of these results is difficult due to different criteria used (ferritin, or sTfR/logFerr index) as well as application of various cut-off values of ferritin (from 20 to 35 μg/L). Here, TFRC is linked to nutritional disorder.