Preparing for 26.2 miles is never easy, but this winter has been particularly trying for runners, who have had to deal with record snowfall in the Northeast.
Before they can even think about challenging Heartbreak Hill, they've had to endure slippery sidewalks, icy inclines and frozen footpaths.
"There are certainly times when you have to be quick," said McKinney, a 38-year-old physical therapist from Canton, who is preparing for his fifth run in Boston and 15th marathon overall. "I find myself thinking 'How high is that snow bank?' in case I have to jump it."
Some might be forgiven for thinking they're in training for the Iditarod.
Sidewalks often remain unplowed, forcing runners to run on streets narrowed dangerously by massive snow banks. Even when sidewalks or streets are cleared, they remain slippery. Cars blast past, inches away, honking horns, and sending frigid sheets of slush onto the runners. Piles of snow at intersections force runners to pause or stutter-step as they peer around them to check for vehicles.
The severe winter weather conditions have some marathoners worried that an inability to train properly will affect their time on race day, April 18 - the first major marathon of the year.
"Last year I finished in 3:13 and I want to take 13 minutes off that, but I don't know if I will be able to do that," said Christina Ardito, a 31-year-old insurance company underwriter from Niskayuna, N.Y. She's been soaked by passing cars and gone through an extra pair of shoes as she trains for her fifth Boston Marathon, and 12th overall.
"I've never seen a winter this bad since I started running," she said.
Four-time Boston winner Bill Rodgers knows a thing or two about running in wintry conditions. He won Boston in 1978 - just a couple of months after the infamous Blizzard of '78 paralyzed the region for days. He's been running in New England winter slop all his life.
"I think all the New Englanders, Midwesterners and Canadians should be given a mile or two head start for having to deal with this," he joked. "The Californians and Kenyans and Ethiopians aren't dealing with the same conditions as us."
Rodgers is not running Boston this year, but still puts in about 50 miles a week and runs competitively.
"When you run on snow, there's more effort, more strain on the muscles and ligaments and tendons," he said. "It's a different kind of running. You're burning more calories and it really wears you down mentally as well as physically."
Rodgers recommends backing off. There's no use getting injured and missing the race.
"It's not getting to the finish that's tricky, it's getting to the starting line," he said.
Some runners say they're putting in more time indoors on treadmills, or finding safer places to run, including parks and cemeteries that tend to be plowed but have fewer and slower-moving vehicles. Some are donning trail shoes with better traction to run on snow or ice, or even using Yaktrax, slip-on metal coils that grip the snow. Runners deal with the constant fear of getting injured and missing the big race.
"The last thing you want to do is roll an ankle or break it," said McKinney, who's taken some spills this winter. "I've had a couple of bumps and road rash, but that's about it."
John Rheaume finds he sometimes can't get into a rhythm while running outdoors in winter conditions because he's slipping and sliding and avoiding cars.
"It definitely takes away from my tempo when I have to adjust my speed or jump over an obstacle," said Rheaume, 29, a music teacher in Douglas who lives in Haverhill and who's running Boston for the first time. "Since I've been running, this has been the worst I have seen it."
The Boston Athletic Association, the organizer of the marathon, doesn't keep statistics on times following harsh winters. Finishing times are more dependent on conditions the day of the race, said race executive director Tom Grilk.
But in his experience, the tougher the challenge, the more determined runners become.
"In a funny kind of way, the adversity spurs you to work a little harder and the enthusiasm goes up as the difficulties go up," he said. "For people who do this, it's just challenge layered on challenge. So, what's one more?"