While bird dog exercises don't look exactly like a real bird dog -- humans lack tails to point with -- the exercise replicates the look of a pointer as best a human can. From a hands-and-knees position, one leg extends back while the opposite arm extends forward. The goal is to improve core strength and the stability of the lumbar spine.
Basic Bird Dog
To do the bird dog, come to your hands and knees. If the surface is hard or your knees are sensitive, put a blanket underneath them. Position your shoulders over your wrists with your fingers pointing forward and your hips over your knees. Engage your abdominal muscles, then lift your right leg straight behind you. Keep the hips level. Once your core feels stable, lift your left arm forward. Stretch your body out long. Keep the back of your neck in line with your spine. Hold for a few seconds before returning to your starting position.
Level of Difficulty
Bird dog is a simple exercise and is appropriate for beginners. But some experienced gym goers might find some challenges. Balance can be shaky here. Muscle tightness in shoulder or hip extensors may make it difficult to lift the arms and legs. Many people also have a hard time leveling the hips in the bird dog. The temptation is for the lifted hip to roll upwards.
The erector spinae, a group of back extensors, are the main muscles used in the bird dog. To a lesser degree, you'll also use the rectus abdominus -- also known as the six-pack ab muscles -- and the gluteus group in the buttocks. Bird dog is gentler on the back than doing crunches. (refs 2, 3)
Take a Tip
The torso muscles quickly lose oxygen when they contract, according to the American Council on Exercise. But a brief break brings the oxygen right back. Therefore, to increase endurance you should do more reps rather than hold the pose for longer periods of time. Start with five reps on each side, holding each for no longer than seven seconds. Over time you can increase the number of reps.