Designed for natural movement and lockdown during intense workouts, the Nike Free TR 7 AMP Women's Training Shoe features a flexible tri-star sole pattern and supportive Flywire cables. Benefits Mesh upper with a TPU cage for breathable support Flywire cables provide a locked-down feel Inner sleeve delivers a comfortable, sock-like fit Nike Free foam sole for flexibility Tri-star flex grooves offer multi-directional flexibility Rubber sections on the outsole for durability in high-wear areas Nike Free Origins After learning that Stanford athletes had been training barefoot, 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 four 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. Breathability Lightweight foam-backed mesh offers breathable comfort through every workout.