So the military got it right when they teach their cadets to stand tall "at attention."
"Chin up, chest out, shoulders back, stomach in."
The Wall Street Journal (21 August 2013) says that "posture can determine who's a hero, [and] who's a wimp."
Research has shown that striking a power pose raises testosterone levels that is associated with feelings of strength, superiority, social dominance, (and even aggression at elevated levels) and lowers cortisol levels and stress.
Power poses or even just practicing these have been linked with better performance, including interviewing and SAT scores.
Body language or non-verbal communication such as standing erect, leaning forward, placing hands firmly on the table, can project power, presence, confidence, and calmness.
It all ties together where saying the right thing is augmented and synergized by looking the right way, and doing the right thing. ;-)
(Source Photo: here with attribution to Official U.S. Navy Imagery)