What Our Gearhead(R) Experts Are Saying:"I wore these through a block of speed workouts on the track, and the Speedboard gave my stride a noticeable pop off every toe-off. At 8. 43 ounces, they barely registered on my feet, even through repeat sprints."On built the Cloud X 5 Running Shoes for the mornings when the workout calls for speed, not just miles. Lace up for a session of intervals or a quick track workout, and the breathable mesh upper keeps feet cool while the Speedboard technology pushes each stride forward with a snappy, propulsive feel. Underneath, Helion superfoam brings a lightweight, springy responsiveness that holds up through repeat efforts, while CloudTec and CleanCloud technology tune the cushioning for sustainable performance without adding bulk. A durable rubber outsole grips through quick direction changes, rounding out a shoe built for runners who train fast and often.