Ultra boost trainers equip your feet with endlessly swift rapid pace every time you lace up built with a foot hugging primeknit upper thats stretchy light and supportive the legendary torsion system stabilises the midfoot for a smoother ride boost technology and a stretchweb outsole combine to harness and unleash the foots energy with every step while the classic torsion system and a fitframe 3d tpu heel keep you supported every minute and every mile