Same question came up in another context recently –
Historically, rape was a captial offence. The offence was correspondingly narrowly defined, and the standard of proof was correspondingly high.
Often / generally, threats or coercion were not recognised as “force” for the purpose of defining rape. Rape was defined as meaning physical force.
Now that it’s not a capital offence by definition, standards of defintion are correspondingly relaxed.
I supposed someone can be “forced” in that their decisions are limited by financial necessity. But they are still choices. Maybe you work that Saturday so as not to lose your job or to avoid some short-term work crisis. But you also start looking for a new job if weekend work is something that is going to be a regular occurrence.
I will never bathe for the sake of another man!
My (poorly made attempt at a) point was the “force” doesn’t necessarily involve courts, judges, guns, or bullets. Maybe that’s why we call it “lethal force” as opposed to just plain ol’ force.
What if you tell your secretary, “Suck my dick or else lose your job”? Is that force/coercion?
When the consequences of not acquiescing are worse than acquiescing, that’s force. (I may be drunk, but that seems right.)
This is precisely why I gave up on Christianity. I couldn’t accept the contradiction of an allegedly benevolent God saying, “Love me or else.”
Somewhere between 10 and 14 years-old. 
Fines, loss of job, foreclosure, loss of citizenship, blackmail, all sound nonviolently coercive.