Golf Channel analyst Brandel Chamblee used an NBC Sports conference call earlier this week to reveal his concerns about the four-time major winner’s gym regime. “I say it with a lot of trepidation, because it’s a different era for sure and I don’t know the full extent of what he’s doing,” said the former PGA Tour player. “But, when I see the things he’s doing in the gym, I think of what happened to Tiger Woods. “And I think more than anything of what Tiger Woods did early in his career with his game was just an example of how good a human being can be, what he did towards the middle and end of his career is an example to be wary of. “That’s just my opinion. And it does give me a little concern when I see the extensive weightlifting that Rory is doing in the gym.” McIlroy, who has made no secret of the fact he has used weights to beef himself up over the past few years, responded by posting a video of himself on Twitter performing squats with weights. The world No 3 later added: “Re the squats it was the last set of 3x3 at 120kg (265lbs). Did 3x10 at 100kg (225lbs) before that. I’m 165lbs. I’m a golfer not body builder.” McIlroy was backed up by Gary Player, who recently admitted he takes umbridge when people talk about Woods having started the gym revolution in golf when he lifted weights long before then. “Don’t worry about the naysayers mate,” said the South African in a message to the Ulsterman. “They all said I would be done at 30, too.” Perhaps feeling he has a point to prove, McIlroy locks horns with world No 1 Jordan Spieth for the second time this season when the Northern Trust Open gets under way in Los Angeles today. Spieth is a man on a mission at Riviera, having narrowly missed out on a three-man play-off 12 months ago won by John Hahn. “For me to win on a golf course that I consider one of the top few in the world, that’s always a goal. It would be amazing,” he declared.