Women's Nike Flex Train Training Shoes The Nike Flex Train Women’s Training Shoes are versatile workout sneakers designed to support a wide range of gym and fitness activities with a breathable mesh upper and a flexible rubber outsole. Lightweight cushioning from a full-length foam midsole provides comfort during training sessions, while the elastic heel band and lace-up closure help keep your foot secure. Built-in flex grooves and cutouts in the sole enhance natural movement for dynamic lifts, cardio, and studio workouts alike.