Twenty-nine of 99 playing rules approved since 1962 by the National Football League have included safety measures and 20 of the 29 were adopted over the last four years. Among them were the following: 1976

Clarified penalty for striking with fists or kicking or kneeing opponent.

Illegal for defender to use hands on teammate to gain height as an attempt to block a kick.

Defender not permitted to rough ball carrier who falls to the ground untouched, by running or diving into him 1977

Clarified restrictions on offensive blocking to include the thrust of a blocker's hands and arms forward to contact an opponent above the shoulders.

Illegal to strike opponent above the shoulders (head slap) during defensive lineman's initial charge.

Illegal for back (or flanker) who lines up inside tight end to move to outside and then back inside to crackback (with bind side block) below the waist.

Defender permitted to contact an eligible receiver either in the three-yard zone or once beyond that zone, but not both.

Illegal fr wide receiver to clip an opponent anywhere. 1978

Permitted defenders to maintain contact on receivers in a five-yard zone beyond the line of scrimmage, but restricted contact beyond that point.

Clarified pass-blocking interpretation to permit extended arms and open hands.

Clarified unsportsmanlike-conduct rule to include forms of taunting or baiting.

Added a seventh official. 1979

Stipulated mandatory equipment for all players to wear in game.

Prohibited all players on receiving team from blocking opponents below the waist during kickoffs, punts and field goal attempts.

Extended prohibited crack-back zone from three yards on either side of line of scrimmage to five yards on either side of line.

Officials instructed to be quicker in whistling a play dead when quarterback is firmly in grasp of any tackler.

Player may be penalized for unsportsmanlike conduct when he commits a noncontact act such as throwing a punch or a forearm, or kicking at an opponent.

Strengthened rule that prohibits unnecessary roughness and specifically outlaws use of the helmet to butt, spear or ram a player not in a position to defend himself, such as a passer, receiver or runner already in the grasp of a tackler.

In lieu of agreeing on proposal to prohibit the chop block on a rusher by a second offensive player, Commissioner Pete Rozelle expressed the club presidents' sentiments against coaching that technique.