Marathons and activity-tracking gadgets — I struggle to understand either.

One exists to create pain, the other to engender painful paranoia.

I acknowledge, though, that some people adore both. In Thailand on Sunday, they ended up on a collision course.

As the Associated Press reports, runners in a half-marathon began to feel a touch vexed at the end of their 13-mile race. This may have been because it wasn’t a 13-mile race. The organizers told the runners to make a U-turn at a point on the route that was not correct.

This meant that an additional four miles were added, making the race sponsored by Standard Chartered Bank a 0.65ish-marathon.

The event’s Facebook page told painful stories of a marathon whose charting was less than standard.

“Such a massive screw up!” Pim Savetmalanond wrote. “Was actually more like 7km additional from the posts by various runners [on] the event page and FB BKK Runners group.”

Another participant, Hanah Manua tweeted that “Many got injured, 21km turned to 27km. Water stations not sanitary. Not organized unlike other SCM abroad. Pissed runner.”

How did runners discover this terrible faux-pas? Their GPS-enabled watches, of course.

“I was shattered and destroyed yesterday,” Maja Prva Laska Navzy posted. “Stopped running at 21K when my GPS recorded 21K. This was the fastest 21K for me but with the additional 7K? Walking the next 7K took me 4hours 47minutes 40seconds 4milliseconds to cross the finish line!” (The “K” refers to kilometers.)

Songrakm Kraison, vice-president of the Jogging Association of Thailand, one of the race’s two organizing groups, issued a mea culpa through the Associated Press.

“The association apologizes for the mistake. It will not happen again in the future,” Kraison said.

Of course, such a mismeasurement doesn’t reflect so well on the sponsoring bank. It would be terribly upset if it made 30 percent errors, especially if it was giving money away.

“As the main sponsor for the Bangkok Marathon, we apologize for this unfortunate incident,” a spokeswoman for Standard Chartered said Tuesday. “This is not something that should have happened and we hear the feedback from the running community.

“Following our discussion with event organizers, they will be sending all eligible runners a 27.6km Finisher Tee as a token of our appreciation for your support,” she said. Well, that should stop them getting shirty.

Not all activity trackers are supremely accurate, but GPS-enabled watches tend to be quite accurate in representing just how far you’ve traveled.

One hopes, of course, that no one’s health was jeopardized by the additional distance.

However, not all commenters to the race’s Facebook page were upset.

“All this GPS measurement is just sets an unnatural expectation,” wrote Ivan Ng from Singapore. “In my days ah, we just ran till we see the finish line…And we didn’t need simi heartbeat monitor to tell us if we’re getting a heart attack, we just stopped running when we ran out of breath.”

And we didn’t even have headphones that streamed us motivating music.

Updated 11/17 at 3:12 p.m. PT with comment from Standard Chartered.