With preparation for the Angie’s List Grand Prix of Indianapolis looming, drivers from the Verizon IndyCar Series and Indy Lights presented by Cooper Tires spent one of their last days off in May trading in their high-performance race cars to interact with a different kind of horsepower.

The inaugural #Horsepower500 at Children’s TherAplay on Indianapolis’ north side Tuesday featured drivers including Charlie Kimball, Conor Daly, James Hinchcliffe, Stefan Wilson and Neil Alberico competing in a tricycle race to benefit The Children’s TherAplay Foundation, which helps special needs children build motor skills through interacting with horses in pediatric physical and occupational therapy sessions. Children can ride, pet and play with horses on-site during their sessions, which helps them develop through a process called hippotherapy.

Nine drivers, joined by INDYCAR broadcast personalities Katie Hargitt and Kevin Lee, participated in an adaptive tricycle race, with each celebrity paired with a TherAplay child. The drivers rode around cones to their partner, who loaded carrots into the tricycle’s basket, after which the drivers raced back around the cones.

The three heat races were all won by Mazda Road to Indy champions, with 2013 Cooper Tires USF2000 Championship powered by Mazda champion Scott Hargrove, 2015 Pro Mazda presented by Cooper Tires champion Santiago Urrutia and 2015 Indy Lights champ Spencer Pigot moving on to the final round, with defending Verizon IndyCar Series champion Scott Dixon entering as a wild card.

In a mad dash to the finish, Urrutia crossed the line first in a dead heat with Dixon, but had hopped off his tricycle to push it ahead at the checkered flag. Despite his plea to “race control,” Urrutia was excluded from the final head, giving Dixon the victory.

The competition, of course, came in a distant second to the chance to interact with the children and raise funds and awareness for TherAplay.

“To have the INDYCAR drivers and Indy Lights drivers come out here and care about this event is beyond our wildest expectations,” said Anders Krohn, organizer of the event and a former Mazda Road to Indy racer. “Originally we were only trying to bring out a few drivers, bring out a few parents and have it be a fun internal thing, but as drivers kept showing interest and more people kept saying yes, we thought maybe this could be something bigger. And then to have it sold out within a week of announcing tickets were on sale was just staggering.”

Kimball, the Verizon IndyCar Series driver for Chip Ganassi Racing Teams, came away impressed.

“It’s really cool for me to see Children’s TherAplay in action,” said Kimball, who was on Team Nikki with a boy named Parker. “His parents were telling me how much stronger he’s gotten thanks to Children’s TherAplay. He’s gotten to that point that he’s strong enough that he can interact with other kids at school and learn from them, and that all started here, so I think it’s really cool to see.”

Daly, driver of the No. 18 Dale Coyne Racing Honda, agreed.

“It’s really cool to share our happiness for the month of May with all these kids here,” he said. “And to raise money for a cause like the Children’s TherAplay is always a great opportunity. I made some new friends today, and it was just really cool, for sure.”

For Krohn, the exciting turnout for the inaugural event has already sparked work for the second running of the #Horsepower500. And with the historic 100th Running of the Indianapolis 500 top of mind this May, he’s thinking longer term.

“I’m thrilled about the first #Horsepower500,” Krohn said. “Maybe one day, well, I won’t be there, but maybe one day they’ll be talking about the 100th #Horsepower500.”