City Surf Fitness opened March 21 in San Marcos. City Surf's workouts are performed on surfboards. Participants work on balance, stabilizing muscles and core work. The studio chain has eight locations, including one in Austin. The San Marcos studio is located at 700 N. LBJ Drive, Ste. 103A, San Marcos. 512-576-3177. www.citsurffitness.com/sanmarcos Additional reporting by Starlight Williams.