American Football Gear

Early American football basically used the ball used for English rugby. After the reform in the late 19th century, the size was reduced and the shape was changed. The American rugby used today is a prolate spheroid with a length of about 11 to 11.25 inches (27.94 to 28.58 cm), a circumference of about 21 to 21.25 inches (53.34 to 53.98 cm) at the center of the ball, and a weight of about 14 to 15 ounces (396.89 to 425.24 grams). Although its sphere is olive-shaped, it is not closer to the standard oval like English rugby, but is slightly pointed at both ends to form a "vesica piscis" (meaning an oval with pointed ends). In addition, this shape is the most efficient shape for long passes with one hand. The similar Canadian football (also known as Canadian soccer) looks more like English rugby and is slightly different in size than American football, but the balls used in both sports are generally interchangeable.

Each rugby ball is made up of four pieces of leather (or plastic), and each piece of leather undergoes a series of weight and crack inspections before workers begin the production process. Two of the pieces are perforated at the connecting edge and tied together with ropes. One of the tied pieces is perforated with two more rows of holes and reinforced in the center to fix the inflatable piston. Part or all of the structural leather pieces of the ball will be stamped with the manufacturer's brand, competition or league name, signature or other imprint. Each piece of leather is lined, and the four pieces of leather are sewn in reverse. The position with the rope hole is not sewn. The leather shell is turned inside out using this crack. Finally, a polyurethane or rubber bladder weighing about 12.5 to 13.5 ounces (354.37 to 382.72 grams) is inserted through the crack, and then a thick rope made of polyvinyl chloride or leather strips is tied along the perforation to tighten the crack. Before use, the ball needs to be inflated to an air pressure of 12.5 to 13.5 psi (86.2 to 93.1 kPa).