A runner guts out the final hill of the 2014 Marine Corps Marathon. (John McDonnell/The Washington Post)

Any woman who has watched a man destroy some expensive plumbing after insisting he knows just what he's doing won't  be terribly shocked at a recent comparison between male and female marathon runners.

It turns out that men have inflated opinions of the speed at which they're going to complete a 26.2-mile run, and they pay for it dearly toward the end of that effort. Women, on the other hand, tend to be more realistic about the task, which works to their benefit.

We know this because a Danish fellow named Jens Jakob Andersen looked at the results for more than 1.8 million marathons worldwide. When he examined the finishing times of the 1.42 million entrants identified by gender, Andersen realized that while both sexes slow down toward the end of marathons, men slow down a lot more.

"Although men are faster marathon runners than women (due to genetics), they are not the smartest," Andersen wrote in his assessment of the numbers. "Women are 18.63 percent better at pacing."

Andersen, who lives in Copenhagen, founded runrepeat.com, which compares various brands of running shoes and is dedicated to helping runners enjoy the sport more by becoming better at it. When I called him, he was pretty blunt about his theory of the male-female marathon divide.

"I think it happens because we men tend to have an unrealistic idea of how good we are," he said. "It applies to everything. Look into a mirror for men, and it'll be, 'I'm super fit and and strong.' And for women it'll be, 'Oh, I'm too fat.' "

So male marathoners, confident that they've trained well, launch themselves off the start line way too fast and crash harder in the final 6.2 miles, after they hit the dreaded "wall." Women aren't perfect — it is, after all, quite difficult to run a consistent pace for an entire marathon without help from a pacer, or unless you are a top marathoner — but they're less confident and more cautious than men, Andersen believes.

"Women are less risk-taking than men," he said.

When it comes to age and pacing, Andersen's numbers show that the oldest (70 or older) and youngest (0-19) runners are the least adept at pacing.

As for improving: Andersen, echoing the advice of many running coaches, recommends that runners seeking to hold a pace start slowly, use a heart rate monitor and train more at the pace they intend to run. Succeeding should shave some time off your result and make those awful last 6.2 miles a bit more bearable.

"It would make running more fun because you would have more success, and more success makes you run more, [which] makes you a healthier nation," he said.

Also: H/t to Marlene Cimons, who finished the Oct. 26 Marine Corps Marathon at the age of 69, and writes about it in today's Post.