Tom Brady's personal trainer took me through the quarterback's intense workout - and it changed my life

A couple of months ago, I tried the intense diet and fitness regimens that 40-year-old NFL quarterback Tom Brady touts in his new book "The TB 12 Method." A combination of workouts focus on "pliability," or adding flexibility to muscles through a series of workouts with resistance bands.

Some, have questioned the legitimacy of the pliability concept. In an interview with the New York Times, one muscle physiology expert called it "balderdash."

Recently, I was invited to visit the TB12 sports therapy center located in the shadow of Gillette Stadium in Foxborough, Massachusetts to get a one-on-one workout with Alex Guerrero. He's the creator of the TB12 method and has worked with Brady as a personal trainer and body coach since 2004. I also asked Guerrero to respond to some of the criticism the TB12 method has received. The following is a transcript of the video.

Graham Flanagan: We're here in the TB12 sports therapy center here in Foxborough with Alex Guerrero, creator of the TB12 method.

Guerrero and Brady have worked together since 2004. They opened the TB12 center in 2013

Flanagan: I want you to take me through a circuit that you might go through with Tom Brady.

Alex Guerrero: We'll do some things to get you warmed up here and then get your core activated, and then we'll get going.

So, we're gonna get him on the X-ciser. Let's go, Graham. Hold tight. Arms straight! Gotta engage that core. Engage those glutes. There you go. Breathe, Graham. Breathe. There we go. Let's pick up the pace. So, don't move those knees.

Flanagan: Don't bend the knees?

Guerrero: Nope, you're right here. So always - right, so full ranges, right?

Flanagan: So all the way here?

Guerrero: That's a bad exercise for him, right? You're not ready for that one yet.

One of the main principles of the TB12 method is "muscle pliability"

Guerrero: Pliability is simply a way to maintain, you know, your muscles long and lean and soft, and it allows the joints in your body to move efficiently and correctly without putting loads on your tendons or your structure.

Some have questioned the scientific validity of pliability. One muscle physiology expert called it "balderdash"

Guerrero: You know, to sit there and say there's no such real thing as pliability - that, to me, is balderdash! We have a lot of laypeople that come here every day. We've had a lot of really elite athletes that have come from all over the world to come here. And I would say, you can't unknow what you know, right? Like, once you experience it and you feel it and you realize the differences it's making in your life - like, that guy who said it was balderdash, he's never gonna be able to convince these people that it didn't work.

Push. Bring that arm out. Punch. Punch hard with the arm and kick back with that leg. There we go. Stay on those toes.

Flanagan: So, what's your sort of takeaway. What's the verdict on me after that little session?

Guerrero: So, we definitely do have some issues, right? You have, you know, hip-instability issues. You have no glute-facilitation, right? Your core is not as strong as it should be, because as you age and get older, those loads are gonna go somewhere, Graham. So, at some point you're gonna be like, "Wow, you know, I'm starting to get neck pain, or "I'm starting to get some nerve impingement" or "I've some cervical compression."

Simple piece of advice would be: work on core-stabilization, glute facilitation.

Flanagan: Cool!