boxing

It's called the 'sweet science' because it's a pun on 'sweat,' and as far as the 'science' goes, it's really elementary physics.

Namely, a hard object accelerating over a distance at a certain force creates an impact of x ft-lbs/in2...

Or maybe it's because Damon Runyon called it the sweet science, and no one wants to question anything Damon Runyon wrote.