Serena Williams works out with UFC Fighter Georges St-Pierre [photos]

Have you ever been curious about how Serena Williams maintains her shape? The tennis ace recently hosted a workout class with UFC Fighter Georges St-Pierre to celebrate the launch of Enduracool, an instant cooling towel that she helped create with Mission Athletecare.

The Enduracool towel is so special because it has the technology to stay cool for hours and helps prevent heat-related illnesses, one of the primary causes of injury during workouts.