The football playing field is rectangular in shape, measuring 100 yd (91. At both ends of the 100-yard dimension, white lines called goal lines mark off the entrances to the end zones. Each team defends one end zone. A team must carry, pass, or kick the ball into the 10-yd (9-m) end zone on the opponents' half of the field to score. Lines parallel to the end zones cross the field at 5-yd (4.5-m) intervals. These lines give the field a resemblance to a large gridiron. Another set of lines, known as the sidelines, runs along both sides of the field. In addition, two rows of lines, called hash marks, run parallel to the sidelines. The hash marks are 53 ft 4 in (16.3 m) from each sideline in college and high school football, and 70 ft 9 in (21.6 m) from each sideline in the National Football League (NFL). Each play must begin on or between the hash marks. Before each play, the officials place the ball either between the hash marks or on the hash mark closest to the end of the previous play. Situated in the middle of the rear line of each end zone are goalposts, consisting of a 10-ft (3-m) vertical pole topped by a horizontal crossbar from which two vertical upright posts extend.
Legal towels must be made of moisture-absorbing material. Also, any sticky or slippery substance is not permitted on the towel. During an authorized time-out, that is held adjacent to the sideline, any number of team members and coaches may participate. Clarification has been made that a post-scrimmage kick situation begins with the snap and that a successful field goal is not included in any post-scrimmage kick enforcement. The following language was removed from the rule: " on the line of scrimmage and. Clarification has been made to the existing authority of state associations for approval of any procedures utilized to continue or terminate contests interrupted by events beyond the control of the contest administrators.
