The "depth" refers to the strike's ability to bypass the protective wall of the rectus abdominis. This is achieved through trajectory (upward or twisting) and fist formation (often using the second knuckle for piercing pressure).

Power is generated from the ground up. Fighters pivot on the lead foot and rotate the hips, similar to a golfer's swing, to put full body weight behind the fist.

Use a quick, sharp exhale to tense the abdominal wall the moment impact occurs. Stomach Vacuums: