English Other Sports / Fitness / Recreation

Hello everyone,

John Kavanagh, a famous MMA coach decribes how he received his black in Brazilian jiu-jitsu:

"In order to become the first Irish person to achieve black‑belt status in Brazilian jiu‑jitsu, after so many years of training, I had to overcome one final massive hurdle. Matt Thornton came to the gym in Rathcoole to grade me in the last challenge. It is called an ‘iron man’ and it requires you to spar with every person in the gym to submission. There were seventy people in the gym that night."

From this description, it is unclear to me what exactly the phrase in question imply.

Does it mean that the person who is going through this test should defeat his opponents exactly by submission one by one?

Or does it mean that he should fignt his opponents one by one until he himself loses by submission?

Thank you.