Warrior III emphasizes the squaring of the hips to the floor while balancing on one foot, unlike Warrior I and II. The psoas muscle (deep in the hip) works with upper thigh of the standing leg to create a right angle shape. The glutes work to maintain the square alignment.
From Standing Big Toe Pose, release hold of the toe and begin hinging your torso forward at the waist and with control, start to extend the floating foot long behind you to enter Warrior III.
Draw the shoulders away from the ears by sending the arms long by your sides. Think about reaching through the crown of your head and keeping your gaze soft at the floor a foot or two in front of you. Lengthen through the spine and neck, and flex through the back foot to help you find stability here. Draw your navel in to engage your core.
Breathe deeply for 3 inhales and exhales and float the foot down to meet the other, returning to a forward fold for Big Toe Pose. Repeat these three shapes on the other side.