Private equity firm Silver Oak Services Partners has invested in Vasa Fitness LLC.

Provo, Utah-based Vasa operates health clubs in Utah. The group has about 150,000 members and 17 gym locations. Terms of the investment were not disclosed.

Silver Oak invested alongside the company's founders and management team. Before the deal, the clubs operated as a subsidiary of national gym chain, but now will be rebranded Vasa Fitness.

Sterling, headquartered in Evanston, Illinois, focuses on investing in business, consumer and health care services companies in the lower middle market, targeting those with Ebitda between $3 million and $20 million. The firm's other investments include Accent Food Services, Construction Labor Contractors and Physical Rehabilitation Network. The firm also bought disposable maintenance supplier Tranzonic Cos. in 2013. 

Earlier this year, AEA Investors, Fitness Capital Partners and Ontario Teachers Pension Plan teamed up to buy gym chain 24 Hour Fitness USA Inc.