Train Speed 4 These are good shoes for functional training, CrossFit, crosstraining ... They are very light and stable, both metabolic Wod worth to lift loads. The tip material and vamp is a kind of plastic, flexible but very resistant friction material. The back is mesh and quilted fabric. The sole is flexible, and the front has a grip taquitos that make much, even too much in some areas. Would like paste that by design, the upper buttonhole Cordonera on the inside of the shoe is "nailed" by certain movements of flexion, which is uncomfortable.