Popsugar Health & Fitness Workouts Best Exercises For Strong Abs I'm a CrossFitter, and These Are the 20 Core-Carving Exercises I'm Obsessed With 28 November 2018 by Jenny Sugar View On One Page Photo 17 of 20 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 17 Knee Driver Begin in an elbow plank position with your abs engaged. Draw your left knee into your chest. Then step your foot back to the elbow plank position. Now draw your right knee into your chest, and then step it back to the elbow plank position. This counts as one rep. Previous Next Start Slideshow WorkoutsAb Exercises