Lie on your back with your hands by your side, with your heels about 12 inches from your pelvis. Press your heels into the floor to come into a bridge position with a neutral spine.
Press your right heel into the floor and engage your lower abs as you raise your left leg until your hip is at 90 degrees, keeping your knee bent. Lower your left leg down, pressing through your glutes so your pelvis doesn't drift to the floor along with your leg.