Participation in Ottawa's annual Race Weekend is hitting record levels and is expected to be one of the largest tourist attractions of the year.

Organizers say more than 30,000 people have already signed up for the weekend races.

"We've already broken last year's participation record, we're well over 30,000 participants signed up for Race Weekend this year," said Susan Longbottom, president of the event's board of directors.

The event has grown significantly since it started in 1975 with just 147 runners.

"There was a formal study done by Ottawa Tourism that estimated the economic impact at $13 million, but that was several years ago. We've grown so much," said Longbottom.

The event, which attracts runners from all levels, is estimated to be only second in size to Winterlude.

"I'd classify it as a really, really nice race. The scenery's nice. The people are all into it. The spectators are there encouraging us so it's really, really fun," runner Pierre Brodeur told CTV Ottawa.

This year, Ottawa's Race Weekend will see several marathon runners competing to secure a spot at the 2008 Beijing Olympics.

Ottawa resident Matt McInnes will be one of those runners. He needs to run the marathon in less than 2 hours 14 minutes -- four minutes below the international standard -- in order to qualify for the summer games.

Even if he makes that time, though, there's no guarantee Canada will send him to the Olympics.

While the runners are busy preparing for this weekend's races, students at Turnbull School in Ottawa's west end are helping to kick off the event with a fundraiser for the Ottawa Hospital.

"You never know when you're going to have a relative in the hospital so it feels good to help other people," said student Katia An.

This year, $45,000 has been raised for the Ottawa Hospital. Over the past 10 years, fundraising efforts have garnered more than $300,000.

With a report from CTV Ottawa's Aliya Jiwan

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