NIKE Women's Free TR Fit 3 Printed Training Shoe Grey/Platinum/Volt/Black synthetic-and-mesh Deep flex grooves promote natural movement for a more barefoot-like feel. The upper is made of thin, lightweight materials with minimal seams to enhance multidirectional flexibility for natural range of motion. The low-profile design lets you feel closer to the ground, with a Phylite midsole that provides lightweight cushioning and enough durability to double as an outsole, dramatically reducing the overall weight of the shoe. Breathable foam in the upper and internal support straps in the lateral forefoot and medial arch offer training-specific support. Raised foam in the arch adds even more support where you need it.