It's obvious what's causing the tummy to jump.

1. Physiological factors

Because the human abdomen has aorta, when the human body is thin, you may see abdominal aorta pulsation, which is generally manifested as a jump in the abdomen.

2. Intestinal spasm

is generally caused by contraction of intestinal smooth muscle. When the intestine is stimulated, intestinal spasm may cause a jump in the abdomen.

3. Rectus abdominis spasm

is generally caused by nervous tension in abdominal muscles. When the patient continues abdominal training for a short period of time, muscle contraction may be stimulated, causing a jump in the abdomen.