The regular heel-drop calf raises make sense.... but read the second half of the article where the author recommends "Walt's SAS":
To carry out Walt's SAS, aka the Balance and Eccentric Reach with Toes, start by standing on your right foot only as you face a wall, with your right foot about 30 inches or so from the wall (you may need to adjust this distance slightly). Your left foot should be off the ground and positioned toward the front of your body, with your left leg relatively straight
Then, bend your right leg at the knee while maintaining your upper body in a relatively vertical position and nearly directly over your right foot. As you bend your right leg, move your left toes toward the wall until they touch, keeping the left leg relatively straight. End the movement by returning to the starting position
Is there a video of someone doing this... that doesn't make sense to me. How far in front of you do you put your off-leg? Is it really 30" away from the wall (because that seems like a lot)?