Dog planing, also known as "frog with head up", is a swimming method. As the name implies, the posture is to swim like a dog, with the head always above the water and the limbs beating the water hard, so the progress is slow. Dog planing belongs to the category of freestyle, because the definition of freestyle does not limit the way of swimming. There are two kinds of dog-planing swimming, one is to paddle with both hands together, and the other is to paddle alternately with both hands. The former is faster than the latter, but it consumes more physical strength. Dog planing is not blind planing. First of all, don't stretch your head too high, lest you get tired after swimming for a while. The neck should not be immersed in water, otherwise the direction and balance will be affected by the resistance in the water. The second is ventilation, with your head exposed and no need to breathe repeatedly. The front hand should regularly press the water up and down to avoid buoyancy sinking, and the back leg should be pushed back to have the power to swim forward. Dog planing swimming can be divided into two parts: pulling water and pushing water. When entering the water, the first thing to do is to pull the water. At this time, you should keep raising your elbow and let your big arm rotate inward. At the same time, continue to bend your elbow, so that your hands can quickly catch up with the forward speed of your body, which can make the movement of water create a reasonable movement direction and call the way. At the same time, it also makes the main muscle groups enter the water pushing action in good working condition, and pulls the water to the vertical plane of the shoulder before entering the water pushing part. The big arm is keeping the posture of internal rotation, driving the small arm and pushing the water back hard. At the same time, make the shoulders move backwards and lengthen the effective stroke route. Pushing the water backwards has an acceleration process from bending the arm to extending the arm, and the palm is from the inside up and from the bottom up to the thigh. In the whole paddling process, the trajectory of the hand starts from the shoulder, then reaches the lower abdomen, and finally reaches the thigh, showing an S-shape.