Flags for offensive holding in the NFL increased by 71% during the 2019 preseason compared to the same time period last year, the result of a yearlong point of emphasis that largely went unnoticed this summer.

According to guidance issued in July, offensive holding will be "more strictly enforced this season, particularly on the backside of the run play or line of scrimmage." Referees who briefed media members during training camp said the emphasis is focused on a technique sometimes known as a "lobster block," when linemen grab defenders around the torso or shoulder to prevent them from flowing to the ball from the backside.

Points of emphasis usually result in a spike of flags during the preseason and at least the early part of the regular season, as players and officials adjust to the mandate. Officials threw 469 flags for holding during the preseason, according to NFL penalty data, compared to 274 during the 2018 preseason.

Offensive holding is a 10-yard penalty.