With mile after mile of joint-jarring impact, of battered quads and blackened toenails, marathon training is daunting under the best of circumstances.
This winter, an especially cruel combination of bracing gusts and numbing cold, courtesy of the dreaded polar vortex, has tested the resolve of the most disciplined runners, particularly the thousands training for their first Boston Marathon.
A year after two bombs killed three spectators and injured more than 260 near the Marathon finish line, the race will return in tribute and defiance, promising a deeply emotional experience many runners say they are determined not to miss. Even as yet another winter storm barrels in, battling the elements is a small price to pay, they say.
“It will be such a special Boston,” said Nicole Quinlan, 40, who is training for her first Boston Marathon and raising money for the Dana-Farber Cancer Institute. “It’s going to be an amazing day.”
The Boston Athletic Association has increased this year’s field to 36,000 entrants, 9,000 more than last April. That includes some 4,500 runners who were prevented from finishing last year's race and well over 3,000 who are raising money for charities.
More than 14,000 entrants will be running the race for the first time, and many are not accustomed to outdoor training in such frigid conditions. For 15 days in January, the high temperature was below freezing, according to figures from the National Weather Service.
A triathlete, Quinlan had previously trained indoors during the winter. But she quickly realized she could never get the miles she required for her Marathon training on a treadmill, and she began running outside in whatever conditions winter threw at her.
Quinlan runs well before dawn, and that first blast of frigid air can be hard to face. But once she is on the move from her South End home, the cold’s grip loosens, and she has the stark splendor of the Charles River nearly to herself.
“It’s just beautiful,” she said.
When she passes other runners, they usually nod at each other, acknowledging their shared fate with a mix of respect and sympathy. On the coldest days, their eyes are all you can see.
Jack Fultz, who won the Boston Marathon in 1976 and is the training adviser to the Dana-Farber runners, said training through a harsh winter can be mentally taxing, but takes a discipline that ultimately pays dividends.
“It just exacerbates the challenge,” he said. “But in the end it makes you stronger.”
And a year after the attacks, this Marathon provides a new level of motivation.
“Every marathoner took it personally,” he said. “They are coming back with a vengeance.”
Strong winds can make training even tougher. Hilary Hall, a mother of three from Cambridge, runs along the Charles River, often pushing her son in a stroller. When the wind is whipping off the water, it almost feels like she is running in place.
“My son will yell at me, ‘Why aren’t we going fast,’ ” Hall said with a laugh. “Sometimes it’s very tough. The cold and wind have definitely been worse this year.”
Some days, Hall picks up her 4-year-old from his day care in Boston to run the 4 miles home. She bundles him up head to toe, straps on her traction cleats and her bright yellow running jacket, and hits the road.
On the worst days, days when the city feels like a frozen tundra, Hall has been tempted to skip the run.
But the Marathon provides strong motivation, this year especially.
Last year, Hall was just past the 25-mile mark when she was stopped. She made her way through the chaos in search of her family, who had planned to meet her at the finish line.
“It was just so scary not knowing where they were,” she recalled.
Fortunately, none of her family was affected. Her husband and brother had taken the subway and had not yet reached the finish line when the bombs went off, while her parents had lingered with her son to feed the ducks on Boston Common.
This year, Hall and other runners have the image fixed in their head: running past the cheering throngs to the finish.
“I really want to be there,” said Hall, who is also running for Dana-Farber. “When you turn onto that last stretch, it’s hard to describe how awesome it feels.”
While New England runners have faced trying conditions, runners in the Midwest have dealt with truly miserable cold.
Jason Hawkins, a 37-year-old from Ohio training for his first Boston Marathon, has often been running in subzero temperatures to steel himself for the rigors of running 26.2 miles.
“Sometimes I tell myself if I don’t run, I’ll pay for it on that Monday,” he said.
Hawkins has battled injuries in recent years, but said he is doing everything he can to take part in this year’s race. Compared to those directly touched by the bombings, a little cold seems trivial, he said.
“You think of the people who lost limbs and how much they have to overcome,” he said. “You just run it.”
The cold has forced Hawkins to get creative. On particularly cold days, he runs with the wind at his back for his entire workout, and rather than turn around to face the wind, he has someone drive out to fetch him.
But even Hawkins has his limits. Recently, with the windchill around minus 30, he surrendered and ran at an indoor track, around and around.
On cold mornings, the idea that it might ever be warm again seems almost inconceivable. Indeed, a recent long-range forecast by AccuWeather called for six more weeks of cold in the Northeast.
Still, as they battle through the winter, many runners look warily toward the spring. By the time April rolls around, it could easily be uncomfortably warm, which most runners agree would be worse.
“I would take the cold every day,” Hall said.Peter Schworm can be reached at email@example.com. Follow him on Twitter @globepete.