Bird Dog You can never go wrong with strengthening your core and one of the best exercises you can do, in my opinion, for core strength is the bird dog. 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. Image Source: POPSUGAR Photography