WHITE PLAINS, NY— Sheraton Hotels & Resorts has entered into a partnership with Core Performance to operate fitness facilities in its hotels. The program was piloted in four Sheraton hotels in the U.S. and will be rolled out across the brand in 2009. In addition to fitness centers, Tempe, AZ-based Core will provide input on in-room fitness and nutitional menu planning. Sheraton is part of Starwood Hotels & Resorts Worldwide.