A, Hemoglobin concentration of male and female groups. aMales significantly different from females (P < 0.05); bweek 13 values significantly different from weeks 1, 5, and 9 (no significant gender-by-time interaction). B, Hemoglobin concentration of iron status groups. aMales significantly different from females (P < 0.05); bweek 13 values significantly different from weeks 1, 5, and 9 (P < 0.05) (no significant iron status group-by-time interaction). Values are mean ± SD.