Where is the power behind your public speaking? For better or worse, it depends on your ability to express confidence and belief. It never gets a boost from a dry, Spock-like recitation of facts.

According to a study by Albert Mehrabian -- one that is widely cited to this day -- our body language conveys 55 percent of the emotion we feel, the voice 38 percent, and the things we say just 7 percent.

In other words, gestures rule the expression of emotion.

Mehrabian’s numbers are sometimes disputed and often misinterpreted, but one thing is certain. Gestures are a language we use to express our feelings. They add intensity and emphasis to our delivery, and they get people to pay attention.

Take the legs of the King of Siam.

Yul Brynner, the great American actor who played the part of the King of Siam and devoted much of his career to The King and I, was known to prepare for each performance by trying to push down the brick wall at the back of the theater.

If you ever saw the show or the movie, you may remember his first entrance. He bursts into sight in a cloud of energy, dressed in silk pantaloons and tight white stockings, comes to a stop in the middle of the stage with his hands on his hips and his feet apart, and stands with his legs radiating power and purpose.

Yul Brynner was no pushover. He was a physical force on stage. He projected a formidable will and a fierce confidence. When he arrived on stage, he did not speak a word, and yet his legs said something very definitive.

Amy Cuddy, a faculty member at the Kennedy School of Government at Harvard, has conducted an experiment with her graduate students demonstrating that holding an assertive body posture for as little as two minutes increases the amount of testosterone in the body, in men and women.

While Dr. Cuddy’s experiment has attracted much attention because of her TED talk, Yul Brynner was familiar with the power of gesture in the 1940s. He had been exposed to the teachings of Michael Chekhov, one of the greatest Russian actors of the early 20th century, and the nephew of the playwright Anton Chekhov.

Michael Chekhov's techniques for stimulating inner states such as confidence and belief were what he called "psycho-physical" in nature. Michael Chekhov taught actors that by making a powerful "psychological gesture," they could produce an altered emotional state.

If Amy Cuddy, Yul Brynner, and Michael Chekhov are right, and I believe they are, then what is the first thing we can do to increase our executive presence and ignite interest in our speeches and presentations?

Be more expressive. Show more confidence. Make larger gestures. Speak with more conviction.

When you do this, the quality of your content will not change, but the audience will pay more attention to your content, and that could make all the difference.