Iron Mike Tyson used to pay sparring partners $100 per round. They didn’t always make it to three minutes.

Tyson, the former undefeated and undisputed heavyweight champion of the world, has laid waste to almost every opponent he has faced, but those victims drew handsome paychecks for the physical abuse they took.

The sparring partners, though they were compensated, took a great deal more punishment for considerably less money. Depending on a fighter’s stature and the amount of work he gave Tyson, he stood to receive only hundreds or, in exceptional cases, as much as a few thousand dollars.