Australian rules football

Australian rules football is played with an oval ball that weighs between 450 and 480 grams (16 and 17 ounces) and has a short circumference of 545–555 mm (21.5–22 inches) and a wide one of 720–730 mm (28–29 inches). Australian football is one of the few field sports that does not use a uniform-sized ground; it is played on an oval field that can vary in width between 110 and 155 metres (120 and 170 yards) and in length between 135 and 185 metres (145 and 200 yards). Two goalposts not less than 6 metres (20 feet) in height are placed 6.4 metres (21 feet) apart at each end of the ground. Two shorter posts, called behind posts, rise to a minimum height of 3 metres (10 feet), with each one placed at the side of a goalpost at a distance of 6.4 metres. The line between the goalposts is called the goal line, and this line's extension from each goalpost to its behind post is called the behind line.