Statistics show: with the last century 60's first national foot type measuring results compared Nike Free 3.0 V2, our country population appeared quite severe flatfoot phenomenon. Especially the 12~30 year-old youth populations, in this 30 years has increased by more than 20%. The cause of this phenomenon is mainly due to long-term wearing sneakers. Wearing sneakers how causes flatfoot? China leather and footwear Institute senior engineer pointed out: travel shoes convenient movement characteristics is not suitable for people in daily life in. Venturi engineer from travel shoes of the following characteristics on its arch effect : the first is the last type design. Travel Cheap Nike Free Run 3, Nike Free Run 2 Hot Sale Online shoes in order to facilitate movement and a long walk, doing last before curling is relatively high, so that the soles of the feet will sink, for a long time will have a sense of fatigue. But the sole and arch front fulcrum, the soles of the fatigue damage will cause foot injury, so that in the course of time formed flatfoot. The second is the sole material. Travel shoes mainly for sports and design, so the bottom ( Tourism soles ) will be relatively hard materials. This is for people in the long time walking to and ground friction generated when a good reaction. But in daily life, so hard soles will make us feel very tired, severe fatigue and damage foot arch and the formation causes of flatfoot. Another is the poor permeability of. Bad air permeability is travel Nike Free Run 2 shoe there is the most common problem. It is extremely easy to breed bacteria, so that the skin disease.