Iron body is similar to iron vest training, but it also employs an external component. Iron body training typically involves using bags filled with various material, such as mung beans, gravel, or steel shot (similiar to iron palm bags) that the student uses to strike his forearms, shins, and body, to allow it to take more damage in a fight without injury. The concept is similiar to how the hands are conditioned in external iron palm.
Dit da jow is also used in iron body training to help repair damage between training sessions. There is also commonly an internal component, such as a series of qigong exercises that are designed to bring qi to the areas of the body being trained.
Much like with iron palm, iron body progress should be made slowly as going too fast could cause injury to the student.