"Dumbbell bird" is an action in fitness. Practicing the seam in the chest can be described as "difficult in difficulty". The thickness of both sides of the middle seam of the bodybuilder's chest muscle is the same as that of the whole chest muscle, and the middle seam is narrow, just like a line. For those who have practiced for many years, the whole pectoral muscles tend to be weaker and weaker, which is not in line with the development level of both sides. If they want to practice chest exercises, they should add bird movements: lying flat on a wrench and expanding their breasts with dumbbells. When expanding, their arms should be arched, which is used to pull muscles and make their breasts more fashionable and sculptural.