Austin, Texas-based Gritness, a recent member of the StartUp Health accelerator, has been quietly acquired, StartUp Health revealed in its mid-year report. MobiHealthNews has learned that Under Armour acquired Gritness, but the acquisition price has not been disclosed. While Under Armour acquired MapMyFitness, MyFitnessPal, and Endomondo for their large user base and well-known brands, Gritness is a relative newcomer. It was founded in 2012 and had raised only about $300,000 in seed funding before the deal.

MobiHealthNews has reached out to Gritness and Under Armour for comment and will update when we learn more about the deal.

The Gritness app is essentially a search engine that helps people find and join workouts. Through the app or website, users can search for workouts or find friends that have similar fitness interests. Businesses can also use Gritness to make their available fitness programs more visible.

The company contends that existing fitness apps are too individualized, whereas people can be motivated to exercise more reliably if they can become involved with group workouts happening in their area.

"Gritness was created by athletes who were fed-up with the level of effort required to get people together for a workout," the founders write on their website, which makes no mention of the acquisition. "It always started with an email chain, that quickly got off topic, followed by text messages, phone calls, and messenger pigeons. What if we could bring it all together? What if we could make it easy to find people that want to ride as fast as you, run as far as you, and lift as heavy as you? That’s what we built Gritness for."

The company has listed 1.5 million activities available to their users in places all over the world. As of March, co-founder Jason Whitson told MobiHealthNews in an email that Gritness supported 21 sports including cycling, running, and yoga and they're accessible via web and mobile apps on Apple and Android.

Gritness cofounder and CEO Tommy Fad is now director of architecture and consumer engagement at Under Armour, while Whitson is now director of engineering and consumer engagement.

Under Armour bought MapMyFitness for $150 million in November 2013 and spent an additional $560 million to buy MyFitnessPal and Endomondo in February. In an April earnings call, the company revealed that it had added 10 million unique users to the platform for a total of 130 million users. Notably, both Gritness and MapMyFitness were based in Austin, where Under Armour's digital health hub is now located.

“There was a bit of concern and trepidation on our part, speaking about how we define victory, that people [were] going to say ‘Now they’ve have been bought by a company, I’m not going to use it anymore’,” Plank said at the time. “We haven’t seen any signs of that. We just see them now having a higher expectation of the product that we’re going to deliver. And I can tell you that everyone -- we’re closing on 500 people working in our Connected Fitness and digital space -- [is] focused on working towards that.”