The Post Sports Live crew talks about the aftermath of the Boston Marathon attack and what it means for security at sporting events going forward. (Post Sports Live)

He started the pedometer on his sport watch, put one foot in front of the other and took off, the very act of running on this Tuesday morning providing some sort of catharsis for Michael Wardian, even though he does so virtually every day, often twice a day. This would be a short run for Wardian — only a few miles or so — since he had put in a long run the day before, and as he looped back around toward his Arlington home, he checked the distance on his watch and stopped when it said precisely 4.09 miles.

On Monday in Boston, the race clock for the Boston Marathon read 4:09 — four hours, nine minutes in — when a pair of bombs detonated near the finish line just before 3 p.m., killing three people, injuring more than a hundred others and leaving an invisible, permanent scar on anyone who has ever loved to run.

Wardian, a six-time winner of the National Marathon, loves it more than most, and on Monday, he had run in his 10th Boston Marathon, and was already back at his hotel, showered and packed for the airport, when the explosions occurred. At first, he figured all the text messages asking whether he was okay were just well-intentioned friends who had seen his time and wondered why he had been so slow. (He was nursing an injury and, instead of competing, was running alongside a slower friend for the enjoyment of it.)

By Tuesday morning, Wardian was back in metropolitan Washington and was just another of the pavement-pounders, the dew-sweepers, the lunch-hour escapists and the hard-core roadrunners — just one of the thousands who daily take to the trails, the backroads and the oval tracks of the region to catch up with a friend or lose themselves in thought over a good, hard run.

“It was powerful,” Wardian said of his run Tuesday morning, which he made in his 2013 Boston Marathon T-shirt. “It was something a lot of people who were [in Boston] aren’t going to be able to do the same way as before, or at all. Running is something that for me has been life-altering. It’s something that allows me to clear my head — a safe place for me to go. And somebody tried to rob that. I don’t want that to be possible. I don’t want them to have that type of power over me.”

They were out there again on Tuesday — on the National Mall and Embassy Row, down the Capital Crescent Trail and the C&O Canal Towpath, along Beach Drive and the GW Parkway, on the high school tracks and neighborhood sidewalks, in packs of twos or threes, with baby strollers or dogs, or simply alone.

“There were plenty of people out there this morning,” said Helen Beven, a personal trainer and elite masters road-racer from Kensington who ran Tuesday morning in Rock Creek Park. On this day, the simple act of passing another runner on the trail took on new meaning, as if the two of you shared a secret knowledge. “You always tend to acknowledge other runners, but I think people were a little more aware of each other.”

One of Beven’s mottos, which she uses with all her clients, is: “Run happy.” But suddenly, it sounds like less of a hokey reminder than some distant goal, out there in the future. Maybe you can reach it again someday, but it won’t be easy and it won’t be soon. In the meantime: “You try and think of other things. You make the workout a little harder. You focus on your breathing. You try and be as normal as you can.”

They’ll be out there again Wednesday morning, too, all these runners — including the self-dubbed “Zombie” group of Howard County enthusiasts that meets every Wednesday at 5 a.m. and does seven to 12 miles through the planned neighborhoods of Columbia. “We’re those crazy people, out there at 5 a.m.,” said their leader, Dwight Mikulis of Ellicott City. “We’re going to push on.”

The next thing the running community is going to have to face, of course, is what to do about all the upcoming events — the 5Ks and 10Ks and marathons and ultras, both the local ones and the ones in far-flung places that draw from across the globe. Do you still put on your event? Do you cancel it? Do you stash policemen at every quarter-mile? Do you still take that cross-country trip for the destination marathon you’ve been training for all these months?

On Tuesday, organizers of this weekend’s GW Parkway Classic, a 10-mile and 5K race, sent an e-mail to entrants warning of “enhanced security measures that will require your cooperation and patience.” Organizers of the Pike’s Peek 10K & Kids Fun Run, scheduled for Sunday in Rockville, have worked with local police to beef up the security presence for the event.

“It takes a lot of dedication, resilience and hard work to prepare for any race, especially a marathon,” said Karen Kincer, president of the Montgomery County Road Runners Club. “You get the nothing’s-going-to-stop-me attitude. It’s not going to stop us. Things might be different now, but it’s the nature of the type of people we’re talking about. They don’t give up.”

And so, yes, George Banker, the local running legend from Oxon Hill — 63 years old, with 92 marathons under his belt at last count — will be out there for number 93, the Potomac River Run Marathon on May 5.

“You start to look forward: Do I stay home and not run anymore? No, but maybe I will be a little more vigilant when I’m out there,” Banker said. “I’ll have to be conscious of what’s around me. But I’m still going to go out. I didn’t do all this training for nothing. I’m doing it because I love it.”

But Alisa Harvey, a former Olympic middle-distance runner and Pan Am Games champion who lives in Manassas, thinks she might dial back her competitive schedule now, after what happened in Boston.

“I thought to myself, ‘Well, I guess I’m going to have to keep my races low-key,” she said. “Stay here in Manassas and Fairfax and run my small races. Because now, you’ll think twice if you want to go to a large race: Is there going to be an issue?”

As for Wardian, the schedule on his Web site shows eight upcoming events — marathons, 50-milers and 100-milers — beginning with the Big Sur International Marathon in California on April 28. He said Tuesday he plans to do them all.

“I will keep running, keep improving, keep putting one foot in front of the other,” he said, “for as long as I can.”