MYRTLE BEACH, SC (WBTW) – Thousands of runners will race all over the city this weekend in the 21st annual Myrtle Beach Marathon.

The race organizers are working with the city and law enforcement agencies to plan security measures and traffic control for the race. More than 5,000 runners are expected to compete in the marathon, half-marathon and 5k races.

A runners expo was held at the Myrtle Beach Athletic Complex on Thursday night. Runners could pick up their numbers, t-shirts and check out some athletic gear.

The Myrtle Beach Marathon requires a lot of preparation before the starter’s pistol goes off.

Two days before the race, crews already have barricades, cones and metal fences ready to go in several spots throughout the 26.2-mile course.

“The city of Myrtle Beach has been working all week long, completely enclosing the finish area of the race, so that no vehicles, no unauthorized people can get over their barricades,” said Harrison Schenck, race director of the Myrtle Beach Marathon.

All three races will start on Robert M. Grissom Parkway on Saturday morning. The 5k race, which is about 3.1 miles, will go down Mr. Joe White Avenue and North Ocean Boulevard, then finish after about a mile of running on the Myrtle Beach Boardwalk.

The marathon and half-marathon will follow the same course for a little more than 11 miles. Those races will go down Mr. Joe White Avenue, then continue on Kings Highway, do a loop in the Market Common area on Farrow Parkway, and go back towards the shore on Ocean Boulevard.

The half-marathoners will turn back on Mr. Joe White Avenue before ending at TicketReturn.com Field through the Grissom Parkway entrance. The marathoners will continue on North Ocean Boulevard into the northern end of the city, running on roads like North Kings Highway, Grande Dunes Boulevard and Grissom Parkway. The marathoners will also finish at TicketReturn.com Field.

You can find detailed course maps here on the marathon’s website.

The Myrtle Beach Police Department will also add more officers from inside and outside the city.

There will be a total of 140 police officers working 12 hours for set up and all of the races.

“We’ve asked for the assistance of our surrounding agencies, those that are around us to include the South Carolina Law Enforcement Division, as well as South Carolina Highway Patrol,” said Capt. Joey Crosby of the Myrtle Beach Police Department.

Police say they want to increase security to prevent any attacks.

“We have developed a security plan for this detail, which is why we’ve asked for an additional presence of officers,” Capt. Crosby said.

Race organizers say they’ll also have volunteers working with police at each intersection on the course.

As for city traffic, the entire course won’t completely close downtown.

“They’re going to close down streets as the runners get to them,” said Schenck, who’s also the operations manager for Capstone Event Group. “So, for example, if you’re at mile 25 and you need to go somewhere at seven in the morning, you’ll be able to get out.”

The marathon weekend continues with another runners expo at the sports complex from 1 to 8 p.m. Friday. There will also be a family fun run at 5:30 p.m. Friday at the Grande Dunes Resort on Marina Parkway.

The 5k race will start at 6:20 a.m. Saturday. The marathon and half-marathon will start at 6:30 a.m.

Schenck says the course will be closed by 1:30 p.m. Crews will completely reopen a part of the course when every runner finishes passing it.

The Myrtle Beach Police Department will have an interactive map of road closures on its website.

You can also call (843) 918-4636 to find out about particular road closures or more race day information.