Aerobatic flying is demanding of both aircraft and pilot. The aircraft must be highly manoeuvrable, yet tolerant of G loadings. The pilot must have skill and stamina. He or she must be mindful of the limitations of the aircraft, of normal human limitations, and of their personal tolerances. The most important of human limitations are the biomedical factors and the pilot’s response to acceleration loadings (G loadings). The physiological effects of positive G loading range from reduced vision to loss of consciousness. The aerobatic pilot needs to understand these effects to fly safely and make the most of the activity.