RIO DE JANEIRO -- The slick Michael Phelps TV ads for Under Armour are said to be the test case for a recent shift in the International Olympic Committee's iron-fisted control over its commercial properties.

But Sidney Crosby has been there, done that.

A Tim Hortons spot featuring the NHL superstar that ran before and during the 2010 Winter Games in Vancouver was the Canadian test case for a non-Olympic sponsor continuing its association with an Olympian during the Games.

Rule 40 of the Olympic charter states "except as permitted by the IOC Executive Board, no competitor, coach, trainer or official who participates in the Olympic Games may allow his person, name, picture or sports performances to be used for advertising purposes during the Olympic Games."

The blackout for the Summer Games in Rio went into effect July 27 and extends to Aug. 24, which is three days after the closing ceremonies.

Corporations or companies not officially partnered with the IOC, and by extension the Canadian Olympic Committee, are not allowed to use an athlete's name or image alongside words such as "Olympic", "Games", "Rio", "medal", "gold" and even "Citius, Altius, Fortius."

It is in the IOC's power to strip medals for violations, although that's never happened.

The IOC wants only the companies who ponied up the millions to have their brand in the Summer Games to get the marketing benefit from them. The organziation relies on each country's Olympic committee for enforcement, which is a tall order given the scope of social media.

It's been an adversarial dynamic with athletes chafing under what they consider the right to control their own brand and make money from it.

There's also been "ambush marketing" campaigns by companies who may sponsor Olympians, but aren't an official sponsor of the Games.

A cheeky campaign launched this year in the guise of a protest movement. The Wall Street Journal reported that Brooks Running Company is behind the rule40.com website selling "generic sportswear" to "support athletes' rights."

Large yellow billboards on trucks at the recent U.S. track and field trials read "Not pictured here: an athlete living below the poverty line to bring glory to their country" and "Dear athletes, if we could wish you luck by name, we would, but it's too risky to even mention ours."

The COC took the outdoor apparel company North Face to court over a clothing line launched prior to the 2014 Winter Games in Sochi, Russia.

There are rules and there are interpretations of rules.

Canada's interpretation of Rule 40 after the Crosby experiment was considered liberal internationally. It is said to have influenced the IOC to loosen its Rule 40 grip slightly last year.

Athletes and their non-Olympic sponsors can now apply for a waiver that allows athletes to appear in generic promotion and advertising during the Games.

The content still can't include any intellectual property deemed Olympic in nature.

The relationship between athlete and the company has to be long-standing and not struck in the weeks before the opening ceremonies.

The Phelps and Crosby commercials contain no mention of the Olympics or medals or the Games in which they are competing. The Phelps ad, which depicts the star swimmer's gruelling training routine, includes the slogan "Rule Yourself."

Current Freedom 55 commercials featuring Canadian decathlete Damian Warner also don't mention the Olympics.

"This is shift in the culture of how athletes can be supported," said Calgary-based agent Russell Reimer. "This is from everything from communicating on social media to being in a television campaign.

"What was so restrictive about Rule 40 was how black and white the rule was and how strongly it was enforced.

"I've been in this business for 13 years. It was the house of 'no' before 2010. Today it's 'Let's figure it out."'

Reimer represents the beach volleyball team of Heather Bansley and Sarah Pavan, and 800-metre runner Melissa Bishop, who are competing in Rio.

"The COC is the leader in this discussion world-wide," Reimer said. "I have agent friends all over the world and there's nothing like this."

Added COC director of strategic partnerships Erin Mathany: "We've sat with the IOC and several of the other countries at a meeting last year and really worked through things.

"We at that table, are a leader in the conversation by far."

But the balance Mathany must strike is a tricky one of protecting the COC's official sponsors and millions they bring in to the coffers, while removing barriers for athletes to court sponsors whether they be Olympic partners or not.

"There's two agendas to manage here," said COC chief executive officer Chris Overholt. "One is the agenda that comes with being an athlete and the great support they can enjoy commercially.

"The other agenda of course is the agenda of our many partners that support the Canadian Olympic team 24-7 and in those in-between years and allow us to do the things we're able to do here, and the world-wide Olympic partners that contribute so much internationally."

Canada's athletes might want more freedom still. Swimmer Ryan Cochrane feels he now has more he can offer a company or brand that previously faced a closed Olympic window.

"It has gotten better than it was and we have more freedom than we had four years ago," Cochrane said.

"Sponsorship is how we make money. We get government funding, we get Own The Podium funding . . . . but to actually make money and make a career out of swimming on top of that, you need that support.

"You want to feel like a professional athlete and these sponsors help you do that."