Adidas looked at 1.2 million foot scans to adapt the fit of the Ultraboost to the female foot shape all around. And that's not all. The rubber outsole also got an update. Hundreds of prototypes were built and tested. Until visible progress was made in terms of performance. The result: 4% more energy return in the forefoot compared to the Ultraboost 21 for women. The shoe also features a comfortable adidasPRIMEKNIT upper and a narrower cut heel area to reduce heel friction and blistering. And the BOOST midsole combines with the Linear Energy Push System for an energetic run. The upper of this shoe is made with a yarn that is made from at least 50% Parley Ocean Plastic - recycled plastic waste collected from remote islands, beaches and coastal regions to keep our oceans from being polluted.