Jake Gyllenhaal: He's a big fan of men's bodybuilding

Sport is about a lot of things. Speed, intelligence, strength. But only one sport focuses on the building of that strength into a beautiful, glistening, well-oiled package, and that's bodybuilding.

Back when I was getting into shape for my movie Jarhead, I worked exclusively with Thad Brockstone, a former bodybuilding champion who promised to take my muscles to places they had never entered before. I was a little skeptical at first. Sure, I was in OK shape, but I had never put my soft muscles into the hands of a man like Thad in an attempt to harden them up really fast.

But after months of one-on-one sessions with Thad, which we videotaped so we could watch later to see how far my muscles had come later, I was the ripped specimen you saw in Jarhead. Even after the shooting of the movie, Thad and I have remained close friends, doing all kinds of stuff together besides working out. He still gives me a tip or two now and again just to keep me on my toes, and let me tell you that he keeps me rock hard.

I started attending these bodybuilding competitions whenever I could, and the magnificence of these men should not go unnoticed. They spend hours in the gym lifting weights, sweating, building mass in all the right places, glowing with the type of sweat and oil that just further shows off their amazing definition. It's an art form.

I've met a lot of these men in their free time, and you'd be surprised how gentle these giants can be. I highly suggest getting acquainted with these events, because thanks to them an especially Thad, they've found a way to make me harder than I had ever dreamed.

Be sure to check out my new movie "Brothers" which opens Friday, Dec. 4. It stars myself, Tobey Maguire and Natalie Portman. It's a thriller and I think you would enjoy it.