A Canadian Olympic rower says the International Olympic Committee's changes to its sponsorship rules don't go far enough to help athletes.

The IOC recently relaxed restrictions around Rule 40, which used to prohibit athletes from promoting non-Olympic affiliated sponsors during the Games, including through social media and blogs.

They now can, as long as they don't link their sponsor with the event.

David Calder, a four-time Olympic rower, says the change is a good start but that there are still too many restrictions around promoting sponsors.

"I don't think we're going far enough down this road to see significant changes," said Calder.

He thinks the remaining restrictions may cause more stress for athletes trying to focus on winning a medal instead of whether or not their last tweet broke an IOC rule.

Many Canadian athletes live below the poverty line while they're in training. Calder says having a sponsor can mean buying better quality food or training in warmer climates during harsh winter weather.

But restrictions around recognition makes it difficult for athletes to find or keep sponsors.

"For somebody like me who isn't a top-tier name at the Olympics, hanging on to that support can be challenging," said Calder.

To listen to the full interview with David Calder, click on the audio labelled: Canadian Olympic athlete speaks out against IOC sponsorship rules.