You touch'em they are down, NO REAL Hitting permitted.
Watch a coupla of Mel Blount fore-arm shivers on wide-outs during the 70's and you will see why the NFL adopted the "Mel Blount Rule".
Watch the 1976 Steel Curtain, Green, White, Greenwood, Holmes. the Stillers started the season, 1-4 after winning two straight Superbowl Rings and lost Terry Bradshaw to injury.
They had 9 games remaining {they only played 14}, and they allowed a total of two touchdowns, and had FIVE shutouts, gave up 32 total points and WON ALL NINE and the division. They lost in the championship game to the Raiders {without any running backs, as Blier and Harris were out}.
Oakland was the better team that day.
With or without injuries, the 1976 Steelers, were the best defensive team in the NFL during the entire Superbowl era, and without offensive injuries, would have won 5 straight Super Bowls.
The difference between the Steelers run and the Patriots run is that the league changed the rules in the ‘70’s to hinder the Steelers (Mel Blount Rule), but changed the rules in the 2000’s to help the Patriots (Brady Rule).