Most people have a hip disparity, which means one hip/leg is stronger and more dominate than the other. Having a hip disparity means that you are going to overload the stronger hip when standing, walking, running, jumping, and every activity and also compensate for the weaker hip during those same imbalances. Overloading leads to many injuries of the foot, knee, hip, and lower back. The weaker hip will usually cause the upper body to compensate by rotating or leaning to the side which can lead to back, shoulder, neck, or arm pain. As you can see, hip disparities can lead to injuries and pain up and down the body and the Downward Dog can help correct hip disparities.
The Downward Dog is also effective at mitigating the negative effects of sitting which I describe as sitting induced chronic flexion. Sitting puts our body in a position where our knees, hips, spine, and elbows are in flexion and our scapula often abduct and our head and shoulders round forward and down. When most people sit, they let themselves lean back and rest against the chair back or lean forward and round their spines, both of which allow our big posture muscles to go to get lazy and weak. The Downward Dog will re-engage our posture muscles while creating extension throughout the body.
Get down on the floor on your hands and knees and position your knees directly under your hips about 6 inches apart and your wrist directly under your shoulders about 10 inches apart. Spread your fingers and thumbs out wide and press your palms flat to the floor. Make sure to keep your elbows straight. This is the starting position.