Under Armour will showcase the U.S. women's gymnastics team and international soccer star Memphis Depay in its biggest -- and most digitally focused -- global campaign to date. And the rising sports brand is not stopping there: Longtime endorser Michael Phelps will join the campaign in March via a short film, and the brand will eventually feature many of its athlete endorsers in social-media executions.

The effort builds on the "Rule Yourself" campaign that launched last fall and featured ads showing Misty Copeland, Stephen Curry and Jordan Spieth in multiples as they rigorously trained. The new campaign continues the training theme, but adds the tagline, "It's What You Do in the Dark That Puts You in the Light." The agency is Droga5.

The gymnastics spot is a high-energy interplay of scenes of the U.S. women's team undergoing their grueling training rituals, set to the driving track "Matangi" from M.I.A. The soccer ad is more contemplative but no less dramatic and intercuts various scenes of Depay's training. It intersperses close-up scenes of the player with gorgeous long-shots that depict him kicking a ball across the field in the middle of the night, while "rahs" of fans play in the background. Both ads were directed by Epoch's Martin de Thurah.

The goal is to use more than 200 pieces of content to go deeper behind the scenes of the training regimens of Under Armour endorsers. The theme goes against the prevailing desire for instant gratification that is embodied in the popular hashtag "FOMO," which stands for the fear of missing out, said Adrienne Lofton, senior VP of global brand marketing for Under Armour. The brand will instead push "JOMO," or the joy of missing out, to signify the sacrifices top athletes must make to reach the top as they step away from aspects of daily life to focus on training.

"It's not always the sexiest conversation you can have with a young athlete, but it is the most important" Ms. Lofton said. "So our challenge and our brief to ourselves is how do we make this sticky enough and important enough to reseed the meaning hard work in a young athlete's mind."

In doing so, Under Armour will turn to digital communication like it has never done before. The brand is changing its media mix from 70% TV and 30% digital to 50%-50%. The strategy includes distributing content via the social-media accounts of Under Armour's paid endorsers, such as Mr. Curry, Ms. Copeland and Lindsey Vonn. Mr. Curry -- who just might be the biggest National Basketball Association star today -- has 4.42 million Twitter followers.

Under Armour will also call on consumers to describe their own training rituals on social media while using "#ruleyourself." Under Armour has arrangements with its star athletes to call out specific user tweets and posts on social media. The brand will also reward some consumers who use the hashtag with gifts such as a t-shirt.

Read more on the campaign on Adage.com.