You may use swimming, running and biking as a way to switch up your daily cardio but have you thought about doing it all it one day?  Well now is the time to test it out and see if you can complete a triathlon.  At the 22nd year of the annual CSTS, you complete a 600-yard freshwater swim, 12-mile bike ride through the park and on Riverland Drive and finish the event with a 5k run.  Push your endurance and feel the burn as you complete these challenges throughout James Island County Park.  Charleston County Park & Recreation Commission, 861 Riverland Dr. Sunday, 7:15am, $55.  (843) 762-2172, www.ccprc.com