I love the Nike Air Zoom Tempo Next% and have been using them about 4 months ago, including sometimes for workouts. I have worn 2 pairs. The first one lasted about 1000km before the inner air pocket broke. The same thing happened to the the second pair but only after about 440km. Has anyone else encountered this? There is no obvious reason why this happened. I did not step on a sharp object. Possibly it is a manufacturing defect, though the first pair lasted for quite a while.