Not all is what it seems when it comes to impressive marathon times.
A Today Show report about marathon cheating focuses on how about one dozen people tried to cheat the Philadelphia Marathon course last year as well as other 26.2-mile races in part to earn a coveted Boston Marathon Qualifying time.
NBC News' Stephanie Gosk spoke to Derek Murphy, an Ohio man who analyzes marathon finishing times using an algorithm and posts irregularities on his Marathon Investigation blog.
"I think most people aren't aware of how much cheating goes on in marathons," Murphy said.
The two major ways that people cheat is by cutting part of the course of swapping bibs – which contain a tracking chip – to register a faster time.
When he crunched the numbers for the 2016 Philadelphia Marathon — one of the biggest in the nation — he quickly found 12 entrants who apparently had qualified for Boston by taking a shortcut.
They had missed timing mats and their splits — the amount of time it took for them to run certain sections of the race — didn't make any sense. In one case, a runner would have needed to make world record time in the final miles for his splits to add up.
Philadelphia race organizers spotted those inconsistencies, too, and quietly disqualified the fishy finishers. But Murphy also found some suspects the officials didn't catch: a couple he believed cheated together, with the husband running with the wife's chip to get her a faster time.
He dug into their history and found more races with peculiar results. In some, timing mats showed the husband and wife with identical splits, suggesting they ran side by side the whole way. But photos told another story: He crossed the finish line alone and she was caught on camera miles behind.
After Murphy confronted them, the couple came clean, admitting they cheated in at least five races across the country, including several marathons. She would peel the chip off her bib and give it to him, and he would carry it across that last timing mat.
The wife said she ran the full distance at each event, just slower than her husband — but their ruse allowed her to collect those coveted Boston qualifying times and, in one case, a trophy.
"I realized it made her happy," the husband told NBC News, which agreed not to publish their names. "And fortunately or unfortunately, putting a chip on another bib is a very simple process."
The wife said she had convinced herself it wasn't cheating because she pounded every inch of the course, had once been able to run as fast as her husband, and never collected any prize money.
Philadelphia Marathon officials have policies in place to deal with cheaters.
"There are runners who cheat in all races," said Alain Joinville with Philadelphia Parks & Recreation. "The scoring company, which is on site at the race, is able to verify the times of all of our winners and those who placed in the top of their categories. For all others, we publish all of the results and if we get inquiries from the public about whether a runner’s time is accurate we check with the scoring company to make sure that the runner in question registered a time at all of our checkpoints and then we double check with course photos."