Flywire technology woven into the upper merges with the laces for a dynamic and supportive fit through the midfoot. The strong, yet feather-light, cables work with the laces to increase support as you tighten them. Stretch yarns are nestled between Flywire cables on the lateral side to provide increased stretch in this high expansion zone, while structured yarns on the medial side supply lightweight stability; uniting to enhance the snug, contoured fit of the Nike Free RN Flyknit. Elastic yarns have been added to the heel to supplement the firm and adaptive feel of the shoe, promoting lockdown and improving stability.