Two years ago, Under Armour was riding high as a top sports apparel and footwear maker.

Then the Baltimore company bought a small Austin fitness technology company called MapMyFitness that set it on a new course.

MapMyFitness, which Under Armour acquired for $150 million, operates a network of websites and mobile applications that allow users to track their exercise regimes.

March 14, 2016 - Kevin Plank, Under Armour CEO, gives a keynote address discussing the topic, How a Sports Giant Is Now Tackling Your Health, during South by Southwest Interactive held in Austin, Texas, on Monday, March 14, 2016. RODOLFO GONZALEZ / AUSTIN AMERICAN-STATESMAN

Credit: Austin American-Statesman

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Credit: Austin American-Statesman

Under Armour CEO Kevin Plank told a South by Southwest Interactive panel on Monday that the startup turned Under Armour into a digital company that sees fitness-tracking technology as a key part of its future.

"Every company is going through this: Are you a legacy company that is established, or are you a digital company that is moving forward?" Plank said. "The companies that will make it have found a way to curate and use data. Data is the new oil. The companies that win are the companies that are using math to inform the decisions that they make."

Following the MapMyFitness deal, Under Armour has purchased two other technology companies, Endomondo and MyFitnessPal. Together they are the foundation of the Under Armour Connected Fitness Platform, which offers a suite of applications  for health and fitness. More than 160 million users have joined its online community.

In January, Under Armour launched its newest product, UT Health Box. A $400 kit includes a scale, and activity tracker and measures heart rates.

MapMyFitness co-founder Robin Thurston "was the great translator for our company," Plank said. "At the time, we had less than 20 engineers in our company. MapMyFitness had a great product and great entrepreneurs, but it was more about the engineers Today there are over 500 engineers and app developers in the company."

Under Armour leased 35,000 square feet at the renovated turbine building, where it currently has 175 employees.

"We have 40 seats open, but I think we could jam more people in," Plank said.

Plank launched Under Armour from his grandmother's basement in Washington D.C. in 1996. A former college football player, he began by selling a t-shirt made using moisture-wicking synthetic fabric.

He got the idea after getting tired of sweating of in t-shirts worn under his football jersey. "No one had ever addressed what athletes wear under their uniform," he said. "No one ever thought about your apparel being anything other than a short-sleeve cotton t-shirt in the summer and a long-sleeve t-shirt in the winter."

His first big sale came from Georgia Tech, which ordered 10 shirts from Plank. That was followed by contracts with Arizona State University, North Carolina State and other teams.

Today, Under Armour is a publicly traded company with 14,000  employees and annual sales of nearly $4 billion.

Even though Under Armour is betting on a wired future, Plank said the company remains focused on building its core apparel business.

On white boards around the company, "The one thing that's written in red ink is don't forget to sell shirts and shoes," he said. "That's what we do at the end of the day. That's how we stay in business."