So James Watt invents the term horsepower to illustrate the power of his new steam engine. For him, it doesn’t matter that horses are of course of different strengths. A heavy cold-blooded horse certainly has more power than a fine thoroughbred. Horsepower is not the same as horsepower. However, he is not concerned with maximum strength, but with the average guidance of a workhorse.
If a horse exceeds the power defined by Watt, for example in a short time in a competition, then it also has more than one horsepower. On average, however, it delivers one horsepower.