High arches prevent the arch from dropping and lowering into the ground in walking/running. This causes a lack of “yielding” into the ground which can result in many compensations. In order to address this, we should re-teach the missing link: Pronation and also likely internal rotation.
The ISA reflects the strategy the body is using to most easily direct air in and out via the path of least resistance. The infrasternal ribs are the most pliable (“changeable”) in the entire axial skeleton, so they are easily reformed because they don’t attach on the sternum.
Our brain is seeking stability. But we need to be able to go through the “typical” gait cycle as normally as we can if we are to conserve the most energy. If we lack a range of motion we do not possess, compensations can occur up and down the chain to “find” that range of motion that might be lacking where we need it.
SURPRISE – Your body is not symmetrical. Actually, almost everything we do is quite asymmetrical.
What it ultimately comes down to is that we favor our right sides and our asymmetrical nature puts us in this position.