When out of symmetry, not only does the body use up extra energy correcting the malalignment, it also becomes UNBALANCED and biased in its actions.
Good balance is very important to many performers. Most obviously dancers, gymnasts, jockies, motorbike riders, martial artists and the like rely on impecible balance to maintain PEAK PERFORMANCE but even in team sports, good balance can mean the difference between staying on one’s feet in a tackle or being able to turn a defender.
Habitual bias of movement that comes from long term asymmetry means that a performer will tend to move in preferred patterns. This results in them having a more limited choice in their movement, thus making them PREDICTABLE and easy to read.