Popsugar Fitness Workouts Ab and Core Workout A Quick and Effective Core Workout January 10, 2015 by Susi May View On One Page Photo 4 of 9 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 4 Circuit Two: Elbow Plank Side Step Reps: 20, alternating sides Start in an elbow plank. Keep your pelvis stable as you reach your left leg out to the left, gently tapping your toes on the ground. Bring your foot back into a plank. Repeat the same movement with your right leg. Challenge your plank by stepping your leg to the side. To modify this exercise, just hold the elbow plank for 30 seconds. Previous Next Start Slideshow WorkoutsStrength TrainingGet Fit 2015Ab Workouts