Different positions: Abdominal muscles usually refer to rectus abdominis. It is located on both sides of the midline of the anterior abdominal wall of the trunk, starting from the pubic bone and ending at the xiphoid process of the sternum and 5-6-7 costal cartilage. The vest line is located on both sides of navel, adjacent to rectus abdominis and oblique muscle outside abdomen.

Different shapes: abdominal muscles are muscle blocks. In the anterior abdominal wall, generally 2-4 transverse tendon structures (tendon strokes) are divided to form 4-8 massive muscle bundles, which are vertically arranged up and down, and there are large groove marks between the blocks. The vest line is the muscle line. It is a combined contour formed by rectus abdominis and oblique muscle outside abdomen, showing obvious concave hook line. Because its shape looks like a vest as a whole, it is called vest line.

The training methods are different: it embodies the training of abdominal muscles (rectus abdominis), mainly by bending the trunk forward and lifting the legs upward, which can be done by hand. The training of vest line is mainly to bend the trunk upwards and lift the legs sideways.