Drax is a jerk when it comes to training and likes to test people's limits, but I will reduce it to five, mwahaha. Either way, I'm sure Leon can hold out pretty well, especially if he only has to worry about guarding / dodging. It will be Inigo on the other hand, who will be expelling more energy in trying to attack the whole time. The test is for Inigo to learn how to break a solid defense under the stress of a time limit. the longer he fights, the weaker he gets.