Rheinhardt Harrison (number 403, center) and his father Dennis Harrison (404) at the start of Sunday’s half-marathon in the Alexandria Running Festival. Rheinhardt Harrison set a world record for a 10-year-old in the event by more than two minutes. (Philip Bowie)

UPDATE: The Association of Road Race Statisticians has decided not to certify Harrison’s May 25 run as a world record for 10-year-olds. The association’s founder, Ken Young, said Monday that the half-marathon course in Alexandria, which had been certified prior to the race, was altered at the last minute and thus was not certified, even if it was longer than 13.1 miles. In addition, Young said in an e-mail Monday, another 10-year-old ran a faster time last year, 1:34:53, which was certified over the weekend. Harrison’s 10-mile record, set in April at the Cherry Blossom 10-Miler in the District, remains the world mark for 10-year olds.

ORIGINAL POST: When last we checked in with Rheinhardt Harrison, he was dominating the field of distance running for eight-year-olds, winning two national cross-country championships and setting records in his age group. But “distance” meant about 1.2 miles. Now, at the ripe old age of 10, Rheinhardt has moved up to the big leagues of distance, and of records.

First, on April 6, Rheinhardt ran the fastest 10-mile race ever run by a 10-year-old, 1:11:24, in the Cherry Blossom 10-Mile Run. The Association of Road Racing Statisticians keeps track of the fastest time run at every age, from six to 85, and Rheinhardt now has the 10-mile WORLD record. Oh, and that was the first time he’d ever run 10 miles.

Rheinhardt Harrison, 10, approaches the finish line in Sunday’s half-marathon at the Alexandria Running Festival, where he broke the world record for 10-year-olds. (Philip Bowie)

But Rheinhardt wanted more. So on Sunday, he ran the half-marathon in Alexandria’s Running Festival, and once again he set the world record for a 10-year-old. But he didn’t just set the record (also in his first-ever attempt at 13.1 miles (!!)). He broke the previous record by more than two minutes. He ran a pace of 7:15 per mile, checking a wristband with mile splits to make sure he was running fast enough for a 1:35:00 half-marathon. His final time was 1:35:02, and is awaiting record certification by the ARRS. And if you think that’s not fast, try a few seven-minute miles sometime. Even better, that is a pace for a 3 hour 10 minute marathon, which is a really exceptional time for an adult, and fast enough in nearly every age group to qualify for the Boston Marathon.

Reminder: He just turned 10 in February.

Rheinhardt is now a fourth-grader at Thomas Jefferson Elementary School in Falls Church, where he lives with his parents Heidi Johannesen and Dennis Harrison and his sister Ella. He is still big on video games and reading, while also playing soccer, basketball, football and taking parkour lessons. And asked why he had moved up from the cross-country distance of 2 kilometers to 10 miles, he said, “My dad promised I could run it when I was 10. I really wanted to do it. It sounded fun.”

Dennis Harrison is also one of the coaches for the Fairfax Police Youth Club’s track program, and said he would not recommend anyone so young typically run 10 miles unless they’ve been doing it for years. Rheinhardt ran his first race at 3, so he’s practically a grizzled veteran. Earlier this year, he ran some five-mile races and felt he was ready to step up the distance.

One problem is that Rheinhardt likes to start fast and then keep going fast, which was not so much of a problem at 1.2 miles, but more of a problem for 13 miles. So his father started the race with him, and gave him a “pace band” to wear on one wrist, with proposed split times for each mile, and a watch, to make sure he wasn’t going too fast — or too slow. Harrison said he watched his son over the next few miles and as he passed each mile marker, Rheinhardt checked his time and was right on schedule, though he’d never used such a band before. The goal was 1:35, which would be two minutes faster than the mark set earlier this month in Kenosha, Wisc., by Noah Bliss.

Dennis Harrison said he peeled off at the five-mile mark and cut over to the ten-mile mark in order to run the last three miles with his son. As Rheinhardt approached, “I had a shoulder cramp. My dad had to massage it.” Harrison just worked out the tightness and Rheinhardt continued. At the 13-mile mark, with only a tenth of a mile left, he was joined by a bunch of FPYC teammates who ran with him to the finish.

The “pace band” that Rheinhardt Harrison wore to show what pace he would need to run at each mile marker in order to break the world record by two minutes. He hit the mark exactly. (Philip Bowie)

“It was fun and hard at the same time,” Rheinhardt said. “I was tired. But it was fun after. They had moon bounces and they had a lot of fun stuff.” So after running 13.1 miles and setting a world record, Rheinhardt played on the moon bounce with his friends. He also got a massage.

For the summer, Rheinhardt is gunning for the national championships at some tough shorter distances — the 800 and 1500 meter runs. There, he is more likely to use his strategy of going “super fast for the first 200 meters. I like to get out front. Then I go from there.”

Here’s our previous look at Rheinhardt, when he was just a lad of eight.

Read more: