Most research on posture and public speaking has focused on two aspects of body language that seem to offer opportunities for improvement with relatively little work.
First, there’s all the study of what Amy Cuddy calls “power poses.” The idea is to stand up straight, to take up more space by putting your hands on your hips like Wonder Woman, or to smile broadly to indicate confidence. The basic idea with all this conscious positioning of the body is that if your mind finds you standing or smiling confidently, you’ll feel more confident.
Cuddy’s initial research seemed to show that merely standing powerfully would cause your body to issue more testosterone and less of the stress hormones. Subsequent research failed to support these initial findings, but participants do report reliably feeling (subjectively) better. So if power posing makes you feel better, there’s no reason not to do it.
Nearness makes their hearts grow fonder.