>1hp is at best one measure of the average consistent power output of an average horse doing a full day of work every day for months. Or about the equivalent of

>1hp is at best one measure of the average consistent power output of an average horse doing a full day of work every day for months. Or about the equivalent of a person doing 0.05 to 0.1 hp. Which is exactly the point. It makes a good unit for figuring out about how much animal an engine replaces.