Not sure if it's related but years ago I was in a situation where someone was really irritating me and I had thrown a fake punch in their direction. Multiple people had accused me of actually hitting them because their nose started to bleed but even they had backed me up that I never touched them. Either that was an energy attack or the fear in them had caused it.
I'd still say from experience you can put energy behind your attacks because I was always a skinny guy and ended every fight with one punch.