Start in Adho Mukha Svanasana. Then inhale and draw your torso forward until the arms are perpendicular to the floor and the shoulders directly over the wrists, torso parallel to the floor.
Press your outer arms inward and firm the bases of your index fingers into the floor. Firm your shoulder blades against your back, then spread them away from the spine. Also spread your collarbones away from the sternum.
Press your front thighs up toward the ceiling, but resist your tailbone toward the floor as you lengthen it toward the heels. Lift the base of the skull away from the back of the neck and look straight down at the floor, keeping the throat and eyes soft.
Plank Pose is one of the positions in the traditional Sun Salutation sequence. You can also perform this pose by itself and stay anywhere from 30 seconds to 1 minute.