Flexible Nike Free technology puts biomechanic comfort and agility under every step in a training shoe that moves with you through circuits, sprints and squats. It's built from the ground up with a wide heel and solid base to stabilize lifts and strength training, with flywire-anchored laces providing a locked-in feel and a dynamic fit that support quick changes of speed and direction. An innovative 7/8 inner sleeve stretches, rebounds and breathes to keep your footing secure as your intensity heats up.