I'll tell you in an ordinary way, first determine the position of the front foot (measured with my own foot). The front foot is one and a half feet from the starting line. After measuring the length of one and a half feet with your own feet, draw a line on the heel and put the toes of your front foot on a line. The other foot takes the middle position of the front foot as a point, knees kneel outward, and the front foot is separated from the knees of the other leg by one and a half punches. The hind foot and ankle are flexed and the forefoot is fixed. When you hear the command of "take your positions", lean forward, bow your head and hold your chest, stretch your arms forward and straighten, and your thumb and other four fingers are in a figure of eight at the back edge of the starting line. When you hear the "Ready" command, take a deep breath and hold your breath. Raise your hips, push your legs slightly (don't straighten your hind legs and front legs, keep a certain bend, and push the ground after starting easily), move forward, make your shoulders exceed the starting line, support your arms on the ground, and your body can start at any time. When you hear the gunshots, your front feet quickly push the ground and your arms push the ground. At the same time, with the movement of the front and rear legs, one hand swings forward and the other hand swings backward.
In front of us, we call it accelerated running. At this stage, we don't need to keep the running distance with low center of gravity according to the individual training level. If the training level is not high, we don't need to run a long distance with a low center of gravity (you can understand what you mean by running 20 meters with your head down).
The next step is to run on the way, requiring a slightly higher center of gravity. When running, keep your thighs slightly bent, don't run completely straight (bending running technique), lift your upper body slightly straight, and quickly lift your thighs and run in.
Finally, sprint. Under normal circumstances, this distance is not trained, and you will feel that your hands and legs are heavy. This requires you to run more often, and there is no other shortcut. In addition, individuals do not recommend sprinting, just run directly. Without the guidance of a special person, it is difficult to grasp its balance and it is easy to fall.
I hope my answer can help you!