Disparity of force can definitely play a factor in your self-defense. There are many legal aspects of disparity of force, here’s a resource that may help bring some understanding to an area that can be confusing:
Perfectly illustrates the variables in the human condition I mentioned early in a comment on a post.
You must be aware of your limitations, limitations are hard for a lot of men to admit. We like to think we’re as virile, strong, and capable as we’ve ever been. Age hasn’t been kind to me, if I’m sitting too long I look like a 100-year-old when I first get up, the joints just aren’t forgiving as the once were.
It’s important for all to remember that because one person was able to mount a successful defense like sixty-five-year-old Michael Monahan in the article, doesn’t mean that same defense will work for others.
Fortunately or unfortunately depending how you’re looking at it self defense and defending your actions are not one size fits all.
In the words of Harry Callahan
A mans got to know is limitations.
I am generally looking at size and demeanor. Size is obvious but demeanor may show that the person, even though smaller, is a fighter or trained in martial arts. Even more so, watching the person may clue you in to drug use that could make them more volatile, erratic or less conscious of pain which all give them a disparate advantage.