He said Rousey works out for six-hours per day, up to six times per week.
Even more unbelievable is the intensity of the workouts.
Here is a summary of Rousey's standard workouts, according to the Glendale Fighting Club head trainer.
Every session begins with stretching.
Tarverdyan says Rousey focuses on getting every muscle group and joint warm to avoid any soft tissue injuries later in training.
"You're stretching out your hips, shoulders, knees," Tarverdyan said.
"You're getting a nice warm-up before throwing any punches so you'll be nice and warm to prevent injuries."
She then skips rope for 10 minutes to get her heart rate up and simulate the kind of fatigue she experiences during a fight.
After this warm-up Rousey begins her wrestling and striking work against a heavy bag both on her feet and on the ground.
Tarverdyan says Rousey does up to 12 five-minute rounds of simulating take-downs on the bag while punching, wrestling and changing directions every 90 seconds.
Then she enters the ring and lets her trainer's hands cop it.
Using boxing gloves, Rousey unleashes a series of punches against her trainer's mitted hands.
The glove work usually lasts from 10-15 rounds of 3-5 minutes.
Tarverdyan said Rousey has been known to do 60 minutes of boxing without a break.
"When you learn how to throw a punch you're throwing it with your whole body - your hips, your shoulders, your core is tight," he said.
"You're engaging maximum focus, maximum speed, maximum power."
Depending on the focus of that day's workout, Rousey then completes a series of fight-specific movement drills carrying a light 1kg dumbbell weight.
Holding the weight, Rousey attempts to build her explosive power by performing her usual uppercuts, jabs and hooks with the same speed she would normally throw a punch without holding the dumbbells.
"It's not much weight so you're not going to get so muscular, but you're going to get toned," Tarverdyan said.
"You're conditioning your body."
She's not finished yet.
Rousey finishes her standard workouts focusing on her core and abs.
Tarverdyan says she does up to 2000 crunches at the end of every workout.
Rousey revealed earlier this week her status as the biggest star in MMA has put a bounty on her head that is motivating her biggest rivals to cause her real damage during fights.
That's why she trains harder than anybody.
She says she is determined not to let anyone else do to her what Holly Holm did when the 34-year-old won the bantamweight world title in the UFC 193 main event at Etihad Stadium in November, 2015.
"I think about getting injuries all the time," Rousey said in The Hurt Business documentary.
"These girls, they're not just going there trying to win. They're trying to maim me.
"They want to be the one that, maybe they didn't beat me, but they gave me a big enough gash on my face where I wouldn't be able to work in Hollywood.
"It just puts more pressure on me to be as perfect a fighter as possible and it makes it so much more important for me as it is to them. That's why I train so much harder than they ever possible could. It's not a bad thing to be scared. It's a bad thing to doubt. I'm full of fear, but without any doubts."
