For example, a human flag requires strong shoulder and abdominal muscles. When you push your shoulders close to your weight and can keep your body at right angles for a few minutes by hanging your legs, you have the capital to practice the human flag. For example, pulling pull-ups up to the waist requires strong back muscles, biceps and triceps.

Personal experience extreme fitness relies on explosive force, not slow exertion in general fitness. You can use barbells and various instruments to impact heavy weights, with fewer times and more groups, to stimulate the growth of corresponding parts and complete powerful movements in an instant. In short, practice strength first and then practice skills.