When We Walk, Our Foot Travels In A Constant Arc, But Our Shoes Are Mostly Flat. Wk400 With Keen.Curve™ Technology Changes That. Designed For Active Walking, It’S Our First Shoe Engineered From The Ground Up To Create A Unique Rolling Feeling And Forward Momentum. Whether You’Re Hiking The South West Coast Path, Cruising Up To A Viewpoint With Friends, Or Commuting By Foot, The Women'S Wk400 Trainer Makes Walking More Fun.