What is the breath-holding of hard qigong? Ask a friend who has practiced to explain. Thank you.

There are many kinds of hard qigong, such as Jingang Qigong and Shisanbao Qigong. Inhale through the nose or mouth, breathe in the air, and then tighten your throat, just like swallowing hard food. You can't do it well at first, but you will become skilled after a few days' practice. Long-term inhalation exercise can improve the impact resistance of viscera, improve muscle tension and increase abdominal reserve. Inhalation is to store the internal air in the abdomen in a short time.

Don't inhale too much at first, but send the inhaled air into the abdomen. It's called holding your breath when you're silent. It won't take long to hold your breath and nobody will be hurt. Just hold your breath and finish the next action.