STL All Sports

American football is played on a field 100 yards in length and 53-1/3 yards wide. The goal-posts in the college game are placed centrally 10 yards back of each goal line to prevent possible injury to players through collision with the uprights; in the professional game the posts are exactly on the lines on the ends of the playing field.

Goalposts must not exceed 20 feet in height. They are 24 feet apart, with a horizontal crossbar 10 feet from the ground.

The ball is prolate spheroid in shape, with a circumference not less than 28 inches and no more than 28 1/2 inches; the short axis shall measure no less than 21'A and no more than 21 1/2 inches; the length of the long axis shall measure not less than 11 inches nor more than 12. The weight of the ball shall be between 14 and 15 ounces and when inflated for play shall have a pressure of not less than 12 1/2 pounds, nor more than 13 1/2 pounds.

Play is divided into four periods of 15 minutes each; one minute rest is permitted between the first and second periods and between the third and fourth, with a 15-minute intermission between halves. The professionals take a 20-minute intermission. The college game is supervised by five officials-referee, umpire, field judge, linesman and electric-clock operator. The professionals use a back judge instead of an electric-clock operator.