There are Qigong methods for the protection of self, such as Iron Vest, and Golden Bell. Iron Vest is the little brother to Golden Bell, and only will serve the practitioner for a few hits and then it breaks down. Golden Bell is a method that is harder to train in, and takes longer to master,but can withstand a lot more in the terms of abuse. The practice of Iron Vest can also lead to premature death of the practitioner if it is shown off to excess. The energy used for protection in Iron Shirt is energy reserved for the later lifetime of the practitioner, and once exhausted leads to heart attack, stroke, and organ failure.
Iron shirt is easier to train in, and hence many more people practice it.
If not used to show off, it is a fine method for emergencies, like if you get into a car wreck, or get sucker punched. Some Iron Shirt methods require that the practitioner prepare before getting struck, others do not. Golden Bell is a far superior method. Whereas Iron Shirt mainly uses external means to acquire the skill, through beating various parts of the body with harder and harder objects, to develop immunity from the pain and shock of being hit, Golden Bell uses a lot more internal meditation, herbs and less of being hit. A tire filled with air is quite strong and sturdy, and the ability of a competent Golden Bell practitioner is far superior to the skill of someone into Iron Shirt.