If Downward Dog never feels like a resting posture, chances are, your legs and hands aren't sharing the weight of your body. As you work to straighten your legs and lower your heels toward the ground, proper hand placement is just as essential to build a strong and stable Downward Dog.
Your thumbs should be facing in toward each other with your fingers spread wide, creating a straight line between your middle fingers and elbows. Actively press your entire hand (fingers, knuckle, and palms) into the mat, and don't let those palms lift — this can lead to major wrist pain and discomfort.
Source: Louisa Larson Photography