It is very rare that people come to us with perfect ankle alignment. This is because everyone has slight variations in joint structure and over the years bones begin to shift slightly according to the forces put through them and the supporting soft tissues around them such as muscles, ligaments and tendons.
When we walk and run the ankle naturally supinates (tilts upwards and outwards) and pronates (tilts down and inwards) as part of the movement. It is only when the ankle moves too far into supination (over-supination) or pronation (over-pronation) that it can become an issue.
Effects Of Over-Pronation
The ankle joint functions as a shock absorber and, when aligned correctly, distributes the shock from motion evenly. Thus when misaligned extra force is misdirected and placed upon the other joints of the leg (hip & knee) and the spine. As you could guess, this can lead to further issues along the kinetic chain. The hip and the knee must rotate outwards to compensate for over-pronation, which in turn can damage the joints themselves and also affect the muscles and ligaments surrounding them.