units of power

It makes no sense to me, intuitively speaking, that 1 unit of horsepower is equivalent to 745.7 watts.

To me, horsepower should be related to the distance that a "standard" horse can pull some fixed amount of mass, in some fixed amount of time. I've forgotten almost everything I knew about E&M, but I'm pretty sure watts have something to do with volts and amps. How does it make sense that you can go from volts * amps to foot pounds / sec?

Yet, as Google says:
1 (volt * ampere) = 0.737562149 foot pounds / sec

Maybe this explains somewhat why I was never any good at physics.