Whoop, a Boston, MA-based fitness tracking company, closed a $55 million Series D equity and debt funding round.

The round was led by Foundry Group with participation from Two Sigma Ventures, Accomplice, Thursday Ventures, Promus Ventures, Silicon Valley Bank, and strategic individuals.

As part of the Series D round, Chris Moody, partner from Foundry Group, has joined Whoop’s Board of Directors. Moody was previously GM and VP of data and enterprise solutions at Twitter. Before that he was the CEO of Gnip, a platform that collects social data, and which was acquired by Twitter in 2014.

“We love the holistic approach WHOOP has taken to ensure a delightful customer experience,” said Chris Moody. “Through their software-as-a-service mindset, the team has created a product with fantastic customer engagement and satisfaction.”

This round comes on the heels of monumental growth to the Whoop membership which includes hardware, software, and analytics to improve performance. Whoop will primarily invest these new funds in consumer acquisition, membership services, and product development.

“We will continue to grow our membership globally and make Whoop the best experience for our members. Human performance is a new category and Whoop has emerged as both the pioneer and the market leader,” said Will Ahmed, Whoop founder and CEO, in a press release.

Whoop provides a membership for 24/7 coaching to improve performance. The company’s membership comes with free hardware (the new Whoop Strap 3.0), a coaching platform designed to optimize behavior, and a community of high performers. Members range from professional athletes and Fortune 500 CEOs to fitness enthusiasts and endurance competitors to executives and military personnel.

Existing investors in Whoop include Twitter CEO Jack Dorsey, former NBA commissioner David Stern and NBA superstar Kevin Durant. Stern was also a part of this most recent round, alongside former Uber and Facebook exec Ed Baker, Netflix co-founder Marc Randolph and MIT Media Lab founder Nicholas Negroponte. In 2017, Whoop signed a distribution deal with the NFL Players Association.

Whoop has raised over $100M to date.