Popsugar Fitness Workouts Best Core Exercises I'm a Trainer, and These Are My 16 Favorite Ab-Sculpting Exercises August 24, 2018 by Tamara Pridgett View On One Page Photo 16 of 16 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 16 Birdog Get on all fours, with your knees under your hips and your hands under your shoulders. Remember to keep abs engaged and keep your back flat. Reach out with your right hand and extend your left leg out behind you. Round your back and head to connect your right elbow with your left leg under your body. This completes one rep. Previous Next Start Slideshow WorkoutsStrength TrainingCore ExercisesTrainer TipsAb Exercises