We've analyzed over a million footprints so that Ultraboost evolves and improves its fit to fully adapt to the female foot. And what is even better. We have redesigned the rubber sole. We have tested hundreds of prototypes Until we have been able to guarantee better performance. The result? 4% more energy than the Ultraboost 21. The adidas PRIMEKNIT upper features a narrower heel design for better support and to prevent blisters. Enjoy each stride thanks to its BOOST midsole with Linear Energy Push system. This shoe features an upper part made with a yarn that contains 50% Parley Ocean Plastic, a recycled material made from plastic waste collected on islands, beaches and coastal communities, preventing it from polluting our oceans.