Size 10 best for someone who wears a 9 or 9.5 in running shoes With supportive cushioning built for a smooth run, the Nike InfinityRN 4 is a brand-new take on a familiar favorite. It's made from our all-new Nike ReactX foam, which gives you 13% more energy return compared with Nike React foam, to help you stay fresh and bouncy. Moderate responsiveness High cushion Flyknit tongue 9mm drop Made for easy runs or beginners **I did 1 test run in these