By Mugo Odigwe

CHICAGO (CBS) — It’s ready, set, and almost go time. The 2019 Bank of America Chicago Marathon takes off on Sunday, and more than 40,000 runners will be joining the race.

Marathon organizers celebrated the opening ceremony Friday morning at McCormick Place.

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Runners will pick up their race packets Friday and Saturday at the marathon health expo.

Even those who aren’t running are looking forward to the race, which is the second biggest marathon in the world.

The health and fitness expo at McCormick Place is free and open to the public on Friday and Saturday. A total of 180 vendors are offering the latest in health and fitness products.

Meantime, runners from all over the world are getting ready for the big race.

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“This is my ninth marathon. The distance is, it’s a long way. You gotta respect the distance. You gotta stay focused. I’m not concerned about the distance. It’s more about the time on the clock. Just try to run the best you can. The key, I think, for every runner is to stay in the moment,” said Cail Batty, a runner from Australia.

Marathon organizers plan to track all the runners through something they call “crowd science.”

All of the 40,000 runners will wear tracking devices, which organizers can monitor from their forward command center.

Crews at the command center can monitor runners on various screens, to see where they are at any given time in the race. That way, if a runner drops out or needs medical attention, organizers will know the quickest way to reach them.

“We’ve had runners that have gone into a medical tent, have had a serious injury, transported to a hospital. We’ve been able to call their family members even before that individual reached the hospital,” marathon medical director George Chiampas said.

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The marathon kicks off Sunday at 7:30 a.m.