The design of theU-type air-gather groovecan effectively change the direction of airflow. The tilt of 25 degrees downward and the wide-narrow shape can make the air effectively gather in the perineum and speed up the flow to out from the tail, so that the heat produced by exercises can be taken away quickly. In addition, the expansion of the blood vessels caused by excessive heating and the soft tissue contusion caused by a lot of sweats.