Middle-market private equity firm Brentwood Associates Inc. bought a majority stake in Afterburn Holdings LLC, a franchisee of the Orangetheory Fitness chain.

Jim Potesta will continue to lead Afterburn as CEO, alongside Marty Reichenthal. Both will keep a substantial stake in the business and serve on the company's board. Afterburn will also add board members from Brentwood.

Afterburn operates 12 Orangetheory studios and runs an additional eight studios in Houston. Orangetheory offers a full-body workout that seeks to generate what it calls the Orange Effect, whereby participants keep burning calories for up to 36 hours.

Piper Jaffray & Co. advised Afterburn in the transaction. Nelson Mullins Riley & Scarborough LLP and Burr & Forman LLP were legal counsel to Afterburn and Brentwood, respectively.