A physiology of excellence is the physical state adopted by a person who is performing at their best. It is achieved by being at-cause about one's behaviour — taking full responsibility for outcomes rather than blaming external conditions.
Being at-cause gives us more control and flexibility, which in turn gives us more choices. This is based on the Law of Requisite Variety — the person with the most flexibility of behaviour ends up controlling the system.
A physiology of excellence is not just a mental state. It is a full mind-body alignment: posture, breathing, muscle tension, facial expression and internal representation all working together to support peak performance.
See also: What is Personal Power? | The Law of Consequences | What is NLP?