G motility, is provided by adenosine triphosphate (ATP). The ATP is formed through two metabolic pathways: glycolysis and oxidative phosphorylation (OXPHOS). Glycolysis occurs in the principal piece of the flagellum and the OXPHOS takes place in the mitochondria, which are tightly packed in the sperm midpiece. The amount of ATP produced by OXPHOS is much higher than that produced by glycolysis,