DYNAMICALLY FLEXIBLE. NATURALLY SUPERIOR.Nike's most natural ride to date, the Nike Free RN Motion Flyknit Women's Running Shoe features a supportive, conforming Flyknit upper and a revolutionary new midsole pattern that allows the shoe to expand, flex and contract with your foot during every step—so you can move more freely than ever before.Superior Natural MovementThe next-generation Nike Free midsole expands in multiple directions thanks to an entirely new tri-star pattern, adding a new dimension of flexibility that delivers maximum dynamic movement with every stride. Plus, the heel is rounded to mimic the shape of your foot and roll naturally with the ground.Enhanced CushioningThe dual-density midsole uses a softer foam core directly underfoot and a slightly firmer foam carrier to deliver cushioned comfort and durability for a smooth, natural ride.Snug FitStrong, single-seam Flyknit includes stretchy polyester yarn for a compressive fit that moves flawlessly with your foot as you run. Flywire cables woven into the upper can be tightened through the laces for dynamic support.More DetailsNotched collar for easy on and offRounded heel for natural range of motionLightweight solid rubber segments under the toe and heel for enhanced traction and durabilityWeight: 164 grams approx. (women's size 5.5)Offset: 4mmNike Free OriginsAfter learning that Stanford athletes had been training barefoot on the university's golf course, three of Nike's most innovative and creative employees set out to develop a shoe that felt natural and weightless, similar to bare feet. The team spent eight years studying the biomechanics of runners' feet in motion. The results yielded a profound understanding of the foot's natural landing angle, pressure and toe position, allowing Nike designers to build an unconventional and flexible running shoe from the inside out.Nike Flyknit OriginsNike Flyknit technology was inspired by feedback from runners craving a shoe with the snug (and virtually unnoticed) fit of a sock. Nike embarked on a four-year mission with teams of programmers, engineers and designers to create the technology needed to make the knit upper with static properties for structure and durability. Then the precise placement of support, flexibility and breathability—all in one layer—was refined. The result is a featherweight, formfitting and virtually seamless upper.