The amount of energy expended on doing a something within the realms of the task…
ie. A black belt isn’t going to exert more energy to block or dodge than an amateur is in any martial arts.
That energy is reserved for other purposes.
This can be applied to any profession. The only way to get to become pro at something is exposure, experience and practice. The “fake it til you make it” Ted Talk ( http://www.ted.com/talks/amy_cuddy_your_body_language_shapes_who_you_are ) is basically encouraging those that self doubt themselves and those that try hard.
She talks about body posture; there’s an underlying message that people who are very critical of themselves will end up self doubting their own abilities.
First day you’re going to suck, but at the same time the more you get exposed, the experience you take in and practice as long as you are continually learning, you will become a professional. Becoming a professional does not come over night.