They condition the heck out of their legs with all kinds of jump variations, rope work, running and weights because they get their power from the ground up. Half the time they let you tire yourself out and then come in for the KO.
The only way to find out is to spar with them. If you're in Houston visit Savannah gym and tell them you want to spar with one of their mediocre fighters
You will not be dissapointed.