Sports Equipment: American Football

We are beginning with the new series of sports video stories: Sports Equipment. We will present you equipment from different sports with technichal details, interesting facts and videos, of course! Let's start with American football.

American football is nearly a prolate spheroid, slightly pointed at the ends. The exterior of the ball is made of leather, which is required in professional and collegiate football. Footballs used in recreation may be made of rubber or plastic materials. Leather panels are usually tanned to a natural brown color, which is usually required in professional leagues and collegiate play. At least one manufacturer uses leather that has been tanned to provide a "tacky" grip in dry or wet conditions. The leather is usually stamped with a pebble-grain texture to help players grip the ball. Some or all of the panels may be stamped with the manufacturer's name, league or conference logos, signatures, and other markings. Four panels or pieces of leather or plastic are required for each football. After a series of quality control inspections for weight and blemishes, workers begin the actual manufacturing process. Two of the panels are perforated along adjoining edges, so that they can be laced together. One of these lacing panels receives an additional perforation and reinforcements in its center, to hold the inflation valve. Each panel is attached to an interior lining. The four panels are then stitched together in an "inside-out" manner. The edges with the lacing holes, however, are not stitched together. The ball is then turned right side out by pushing the panels through the lacing hole. A polyurethane or rubber lining called a bladder is then inserted through the lacing hole. Polyvinyl chloride or leather laces are inserted through the perforations, to provide a grip for holding, hiking and passing the football.

(video: Making An American Football)

Technical Characteristics:
Length: about 11 inches (28 cm)
Circumference at the center: 22 inches (56 cm)
Air pressure: 12.5–13.5 psi (86–93 kPa)
Weight: 14–15 ounces (397–425 g)

(source: Wikipedia)