Running forks are caused by the fact that warm-up activities, also known as preparatory activities, are not done properly or adequately before a running activity, or other strenuous activity. Because of the sudden strenuous activity, the muscles quickly into a state of tension. But the visceral organs of inertia, and not be able to immediately move up, in fact, is not enough warm-up, can not immediately move up, will not be able to meet the muscle activity required nutrients and oxygen, so that the breath immediately become nervous, rapid, and thus spasm. Or when the body’s oxygen demand suddenly increased, the breathing is not smooth, is their breathing is not adjusted, just fast frequency of superficial breathing, causing respiratory muscle tension and lead to the final spasm, is the fork in the air. In the future, before strenuous activities, in order to avoid the occurrence of fork in the air, sure to do a good job of adequate warm-up activities, so as not to then carry out strenuous activities before the spasm of the respiratory tract, resulting in fork in the air.