Susan Kolbinsky had logged 23 miles of her 130th marathon, this one in Boston, when her husband called with news of the bombings. Not knowing where to go, she did what any serious runner might: she kept running.

Hours after the attacks, the Peachtree Corners woman sat in a friend’s Boston apartment and reflected, with bewilderment in her voice, on things changed. What she, like so many in the global tribe of runners, considered almost a sacred sport — a time to reach the far limits of physical endurance while quieting the brain — now carries a wearying reminder that no place is guaranteed safe.

“What kind of person would do this at a race?” said Kolbinsky, a teacher and employee of Jeff Galloway’s running school. “I really have never thought about my security … “

In the day following what authorities are calling a terrorist attack, Atlanta runners said they don’t expect a public race to be wholly secure, but they never thought someone would strike in a way that felt so deeply personal.

“The most harm you’re worried about is spraining a muscle,” said Cindy Kirkland, of McDonough, who with dozens attended a vigil Tuesday morning at the Big Peach Running Co. in Midtown.

Since Monday afternoon, emergency managers, event organizers and race directors have fielded an onslaught of calls about what, if anything, they can change to make public events safer. A chief concern is the upcoming AJC Peachtree Road Race, a signature event that draws more than 60,000 runners and their families to the city.

What’s most unnerving, some runners said, is that the race is held on Independence Day. Boston’s carnage happened on another Revolutionary War holiday, Patriot’s Day.

“The first thing I thought about (after seeing the attacks) was the Peachtree … and it’s a bigger race,” said Scott Phillips, an Alpharetta man who is set to run the 10K for the first time this summer.

Nate Price, an Atlanta-based salesman of athletic gear, enumerated the obvious challenges in policing so public an event: “It’s so difficult to control, seeing how it’s not a ticketed event. Anyone can participate, or watch and cheer, and with that comes the risk of this happening.”

Price ran the Boston marathon in 2011 and plans to try to qualify for the Massachusetts race in 2014. The bombing won’t deter him, he said.

“It’s one of those things you keep in the back of your mind — but to remember, not fear,” he said.

Stewart Verdery, a former Bush administration Department of Homeland Security official, said that for people in his profession, big races are notoriously worrisome.

“It’s essentially a giant, un-guardable event,” he said. “… marathons in particular have always been a major concern for security experts, as it’s a lot of people (and) you wouldn’t necessarily recognize a nefarious person among the crowds.”

Peachtree Road Race officials have said little since the tragedy, though organizers with the Atlanta Track Club, which hosts the race, sent a letter to members assuring them they are reviewing safety protocols with emergency management officials.

Mike Wien, who sits on the track club’s board of directors, suggested that some elements of the race may be altered.

“I’ve already talked to our executive director and we are very sensitive about things we might have to change about that race to make sure we’re sensitive to safety,” said Wien, who ran the Boston race Monday.

Jeff Carlyle, a security expert who helps coordinate road races, said he expects extra measures including roving patrols, officers on motorcycles, and enhanced presence at the finish line. Carlyle, who is not involved in the Peachtree Road Race, said safety officials might also consider keeping spectators farther away from the route.

But what he doesn’t expect is for the bombing to deter people from participating. “I think Americans will keep doing what they do,” he said.

Especially runners.

Jeff Campbell, a marathoner and an apparel buyer for the Big Peach stores, spent much of Monday seeking word from running mates who participated in the Boston race. At the same time, he put the bombing firmly in a global context.

“Forty-five people in Afghanistan are killed everyday,” said Campbell, shaking his head. “We don’t think twice about that.”

Kolbinsky, who arrived back in Georgia Tuesday, said the bombing did alter her plans: From now on, she’ll never run without her mobile phone. Beyond that, she’ll do what marathoners do: run, and keep count.

“Today would have been 130 marathons,” said Kolbinsky, who was diverted off the course by race officials less than a mile from the finish line. “I’m still at 129.”