Lululemon Athletica picked a former top Nike executive as its next chief executive as the athletic apparel retailer known for its stretchy yoga pants faces pressure from its founder and a large activist investor to revive its struggling business, the company said on Wednesday.

Heidi O’Neill who had been President, Consumer, Product & Brand at athletic footwear and apparel company Nike will join Lululemon in September as CEO. She will replace Calvin McDonald who stepped down amid heavy pressure at the end of January.

Lululemon’s stock price has tumbled 38% in the last 12 months, shrinking the Vancouver, British Columbia-head quartered company’s market value to $18.8 billion, as American sales contracted last year.

Customer tastes have shifted to competitors like Alo Yoga and Vuori and cheaper versions of the company’s athletic wear are appealing to more price conscious consumers.

Investors reacted poorly to the news sending the stock price down more than 6% in after hours trading.