Unlike other systems that make use of deeper, more formal stances, Tae Kwon Do practitioners stand virtually upright. Although the lower, rigid stances of other systems do provide their practitioners with a high degree of stability, the philosophy of Tae Kwon Do is that it is better to be able to move quickly on your feet rather than to be firmly rooted in one place.
Black Belt Tae Kwon Do, by Yeon Hwan Park and Jon Gerrard