Kevin Plank is stepping down as Under Armour CEO after spending over the last two decades at the helm of the athletic sportswear brand.

The current COO, Patrik Frisk, will assume his new position on Jan. 1, the company said in a statement to CNN. While Plank is stepping down in his current role, he will continue to serve as the executive chairman and brand chief. The changes come as the company's North American sales continues to struggle as seen in the most recent earnings report. UA sales in the region dipped 3% from a year ago while shares are down 23% since July.

“As my partner during the most transformative chapter in our history, he has been exceptional in his ability to translate our brand’s vision into world-class execution by focusing on our long-term strategy and re-engineering our ecosystem through a strategic, operational and cultural transformation,” Plank said in a statement.

As the story goes, Plank founded Under Armour in his grandmother's basement back in 1996. It took the company close to ten years to eventually establish itself as a competitor in the footwear space, and netted $5 billion in annual sales last year.