Wednesday’s announcement that the Oct. 25 Marine Corps Marathon would go on as scheduled was a surprise to many, especially as it came amid a wave of cancellations of major fall marathons. New York City had thrown in the towel just minutes earlier.

The announcement also contained an unwelcome surprise for some runners: They will have less time to finish.

Longtime race director Rick Nealis said the change is one of many his team is agonizing over in trying to reinvent the race in a way that will mitigate the chance of spreading covid-19.

From the little things, such as orange slices on the course (none), to the big things, such as self-serve water stops, this fall’s marathon — if it takes place — won’t look like any previous version.

The most controversial change, however, has been the amount of time runners are allowed on the course.

This week’s announcement noted that runners would need to average 12 minutes per mile rather than the 14 minutes they have been allowed previously — and it leaves open the possibility of further tightening.

Over 26.2 miles, that is a huge difference — runners who signed up believing they would have a little over six hours to finish have just 5 hours 15 minutes.

The limit hit doubly hard because the race, called “The People’s Marathon,” doesn’t have prize money to attract a truly elite field and has long been considered a haven for first-time marathoners and for back-of-the-pack folks who can’t meet the tighter time restrictions at other races.

Nealis got enough blowback that he sent a letter to runners Thursday explaining the decision and posted it on the marathon’s Facebook page. Within two hours, the post had hundreds of comments.

“Many other large events have canceled but our Marine instinct is to lean in and fight for the possibility of hosting a live marathon,” the letter said. “This means a major overhaul of how the MCM looks and operates so social distancing considerations may be incorporated.”

Put simply, the start has to be much more spread out, Nealis wrote, so runners will have less time to get to the finish.

“The critical things are space, size and time,” Nealis said minutes before the letter went out. “Those three things are driving all my decisions right now.”

Because of social distancing guidelines, Nealis needs to create a rolling start that avoids more than 500 people in one place at a time yet allows streets to clear by the agreed-upon deadlines set by local jurisdictions.

Nealis hopes to start runners in 24 waves that would go off at five-minute intervals. But a drawn-out start means a tighter time window. Organizers estimate the time limit, along with a reluctance from faraway participants to get on planes, will cull the field — which filled up in March — from 22,000 to a manageable 12,000.

All runners have the option of deferring their entry (for a $30 fee) to one of the next three years. An accompanying 10K has already been canceled with a virtual option.

Of course, this plan assumes that gatherings of even 500 people will be allowed. In Virginia, the maximum rises to 250 on July 1. The District’s is still 50.

“We still might cancel and nobody runs,” Nealis said, noting that a surge in coronavirus cases in the area or a decision from any of the seven jurisdictions through which the course winds could scuttle the race. “But at least right now, 12,000 people get across the line. I know that’s not good odds — I’m only taking care of 40 percent of my runners. But I can’t do any more.”

If the race goes on, it will be streamlined in other ways as well.

For instance, Nealis said, there will be no prerace carbo-loading dinner. The “Runner’s Village” and staging area will be tightly controlled and will cover the entirety of the Pentagon parking lot — enough space for social distancing.

Runners will not have to run in masks but will need to wear them until they start the race. There will be no post-race party, no music, no beer garden.

On the bright side, the race will yield what might go down as one of the oddest pieces of race swag ever: Each finisher will receive a Marine Corps Marathon-branded face mask along with their medal.

Built-in distancing

Marathons have some advantages over other events when it comes to social distancing.

For one, nearly all of them occur outside. Infectious-disease specialists say it is more difficult for viruses to spread in fresh outdoor air, especially when people are constantly moving.

Because the races are so long, runners naturally spread out along the course. Even before social distancing, it would not be unusual to be more than six feet from other runners for the better part of most marathons.

However, there are some parts of the normal operation of a marathon that just won’t work when you’re trying to squelch an easy-to-spread respiratory disease.

The most problematic places are the start and the finish.

Normally, runners crowd to the start in one long bunch, hundreds or thousands packed shoulder-to-shoulder, waiting to be sent off. Afterward, they often sandwich themselves into raucous finish festivals, with entertainment, food, beverages and activities for families that last for hours.

This year, finish lines at marathons will be designed for efficiency, said Rich Harshbarger, CEO of industry group Running USA: “You’ve finished, here’s your medal, here’s your food — please leave.”

Marine Corps is among the largest races still on the fall calendar, but it is not the only one. Chicago is still scheduled for Oct. 11, although organizers hedged in a June 8 statement, saying, “We are unable to say definitively whether or not the race will proceed.”

A new running normal

The Sanford Fargo Marathon is coming up Aug. 29, and the industry will be closely watching how it goes, said Harshbarger, former director of the Detroit Marathon.

He said race directors are trying hard to find creative solutions, such as dumping expos in favor of drive-through number pickup. Masks may be encouraged (or required), and spectators may be discouraged.

Some races are talking about requiring runners to carry their own fluids, Harshbarger said, and others plan to set up touchless dispensers so runners can fill cups or bottles that they carry with them.

He said you also may see more people in new roles, such as spritzing porta-potties with sanitizer after each use — perhaps the worst marathon volunteer assignments ever.

Even with all these precautions, organizers know they can’t guarantee safety.

“Obviously, there’s risk, but there’s a lot of upside to this,” Nealis said. “We’re trying to get some sense of normalcy back. But obviously if covid is a much bigger problem come September, you could see us canceling because that’s the right path.”