Have you ever watched as a big fish is played well with a fairly flexible rod? You will always see a very even and constant ARCH during the engagement until the fish is either landed or lost. The extremely important point of this arch is in it's ability to deliver pressure/torque in a balanced means without causing too much strain. The exact same physical attributes are engaged during a simple fly cast, every time...without fail, yet rarely discussed and definitely not understood. However,once this constant is recognized as being part of every cast it is very helpful to know and understand it's importance.
Once fly casters know this rule it becomes a friend in every cast, allowing us to deflect our timing and body movements as needed. That is why so often during casting presentations and clinics you will hear me say "I have difficulty in making a bad cast!" not from bragging but from true difficulty in my minds recognition of what not to do,ie: Muscle Memory. Without question my body reacts to the many external obstacles that present themselves during every casting situation; like compensating for wind,trees,and so on.
A good parody would be to remember what happens when you shift gears in a vehicle from 1st to 2nd and so on,we react to a tone from some deep place within our mind,not always at the same time yet always close and typically effective.