Why the average American runner 'has never been slower'

If you're planning to enter a race, allow a little extra time to reach the finish line. You're not as fast as you used to be.

It's not just you. Americans on the whole are not running as fast as we used to, and we're getting even slower every year. The only thing we're quick at is coming up with excuses to rationalize the slower times we're posting.

This news comes from Jens Jakob Andersen, a statistician at the Copenhagen Business School. He's a former competitive runner who uses his spare time to amass and analyze data about running. He crunched the times recorded by 34.7 million American runners in nearly 29,000 races — marathons, half-marathons, 10Ks and 5Ks — from 1996 to 2016.

His conclusion: "The average American runner has never been slower."

He does offer one caveat: This doesn't apply to elite runners. Competitive runners continue to improve year-over-year results.

As for the rest of us, plop down on the nearest couch and listen to what Andersen has to say. By breaking down the data into subgroups, he has put the kibosh on every excuse we've come up with for slowing down.

Myth: The number of casual participants, including people who walk-run or even walk an entire course, is rising. Because they don't train as much as the more enthusiastic runners, their times are slower.

Myth: The number of women participating in races is rising. While there are some very fast female runners, on average women tend to be slower than men.

Fact: Women's times in isolation are slower, too. The average marathon time for women has increased nearly 10 minutes since 2000.

Myth: It's the baby boomers' fault. They made running a mass sport, and now they're getting older and slower.

Fact: Of course, individual runners are going to see changes in their athleticism as they age, but these findings cut across age groups. The argument doesn't explain why today's 30-somethings are posting higher times than their counterparts a decade ago.

What does Andersen think is causing all this? While pointing out that the study was not set up to draw causative suppositions, he does have some ideas:

• A jump in diabetes and hypertension.

• A decrease in overall health (as measured in health care expenditures).

There is one last myth that has drawn Andersen's attention: the theory that distance running is losing some of its appeal to activities such as biking and that, as it does, participants for whom running is a struggle — i.e., the slowpokes — will drop out of the statistical pool and our collective times will improve as a result. So far, it's not happening.