The NFL has asked teams to stop using some high-impact drills at training camp practices, including the Oklahoma drill.

The decision stems from the league's ongoing effort to reduce concussions. The recommendation came in response to data that showed a high rate of concussions during the early part of training camp in recent years.

Competition committee chairman Rich McKay said, "I think some of the coaches were a little defensive at the start, and probably the biggest advocates at the end."