By Rusty Simmons Updated 4:17 pm PDT, Friday, July 20, 2018 In the wake of Sam Warburton’s shocking retirement this week, some of rugby’s top brass used Friday’s opening of the Rugby World Cup Sevens as a platform to address injury concerns in the game. Just ahead of one of the sport’s most prestigious tournaments, Warburton, who captained Wales a record 49 times, sparked debates about tackling rules and training regimens when he said he couldn’t return from neck and knee surgeries. “Before, when you got knocked in the head, it was something brave to carry on playing,” said World Rugby vice chairman Agustin Pichot, the former Argentine captain. “The game has changed. The safety of the players is priority No. 1.” Pichot met with the players association last month to discuss possible limits on training and intimated that there may be changes coming with regard to high tackles. Training limits are more problematic than tackling rule changes, because the rugby governing body can make suggestions to national teams, but players also log time with a variety of club teams in a sport that is played nearly year-round. window._taboola = window._taboola || []; _taboola.push({ mode: ‘thumbnails-c’, container: ‘taboola-interstitial-gallery-thumbnails-3’, placement: ‘Interstitial Gallery…