Jennifer started a blog on self.com talking about her triathlon training progress and charity initiatives. You can check out her blog on SELF’s website or go to our special Blog category.

Here are all the blog enteries so far:

#1 For the kids (August 18)
When SELF’s Most Inspiring Woman of 2008 and September cover girl, Jennifer Lopez, told us at her photo shoot that she wanted to compete in a triathlon, no one was more thrilled than our own resident triathlete, editor-in-chief Lucy Danziger. Then we heard Lopez would race to raise money for one of her favorite causes—Childrens Hospital Los Angeles—and wanted to share her training experience with SELF readers. We couldn’t contain our excitement! SELF is all about being your best inside and out, and that includes giving back. Lopez is dedicated to empowering women and children, and Childrens Hospital is a leader in pediatric and adolescent health and research, ranked among the top in the nation. She continues to inspire us!

So to kick off her blog, the superstar new mom of twins invited Danziger to spend the afternoon at her Long Island, New York, home, training and trading stories. The only way to describe the day: inspiring, of course—and a blast! Lopez is in amazing shape—all her joking and funny face making aside, we saw toned, sexy muscles and yes, flat, rock-hard abs…just six months after having babies! But best of all, she’s happy and having a wonderful time.

From left: Benny Medina, Danziger, Lopez and trainer Gunnar Peterson

“I’ve always loved sports. I used to be on a track team in school. And that’s probably why I can think to myself now, Yeah, I can do this, which is totally crazy! The team was a big part of my life back then and taught me so many things. When I look back on my life and what I’m able to do, it’s partly because of that early training. It taught me discipline, how to be committed, about striving to win, stamina, all that good stuff.

“The sports training also helped me deal with losing and rejection and all the things you go through when starting out in show business. I think that’s why I was able to bounce back all the time. With track, I didn’t let anything get to me. I would just think, Whatever, tomorrow’s the next race, and I’m going to train harder and win next week. And I won maybe 70 or 80 medals and trophies over those years. I should dig those out!

“Now I’ve come full circle. I don’t expect to win this race; my goal is to finish. I’ll probably end up crawling across the finish line, but I’ll do it!”

Don’t let her self-deprecating banter fool you. As with everything Lopez does, whether it’s raising twins Max and Emme; reentering the working world as an actress, recording artist and entrepreneur; or initiating philanthropic projects, she’s putting 110 percent into workouts with trainer Gunnar Peterson. You’ll read all about it here over the next few weeks: how she fits in workouts while staying dedicated to her babies and husband and juggling a career (sound familiar?), what she’s learning and how she’s overcoming challenges (anyone else ever “eat it”—her words—on a bike!?). So stay tuned. You’ll be inspired, learn a lot and get motivated to reach your own fitness goals. (Need some guidance? Check out SELF’s Reach Your Goal program.) As for Lopez, we know that not only will she cross the finish line with a strong stride and a smile, we wouldn’t be surprised if she soon had another medal to add to her collection.

#2 Jennifer Lopez talks tri and charity in Central Park (August 19)

We’re not the only ones excited that Jennifer Lopez is competing in a triathlon for charity. She and Lucy Danziger, SELF editor-in-chief, were guests on Good Morning America yesterday spreading the news.

The pair chatted with anchor Chris Cuomo live from Central Park about raising money for Childrens Hospital Los Angeles, which Lopez has worked with for many years, and the challenges and rewards of training. Her advice to other novices thinking of competing: You can do it, too! “Start slow and give yourself time to work up to your goal,” she said. “It’s hard, but I have more energy, and I feel proud of myself. When I’m training, I keep telling myself, ‘It’s for the kids.’”

Doing it “for the kids” was a main reason Lopez decided to compete in the triathlon , and she’s thrilled to raise money and awareness for one of the top children’s hospitals in the country.

The segment was a huge success, except for one hiccup Jennifer had on her way in to Manhattan:

“We were late because we got a ticket by the tunnel! The police told the driver to pull over. I was sleeping in the back, and I’m like, What are we doing sitting on the side of the road?! I gotta be on the air in 15 minutes! Let us go! They didn’t really see me, though. We took the ticket, then drove there as fast as we could.”

Luckily the producers switched the segment’s time slot, and Jennifer made it on the air to inspire even more women.

#3 Sitting pretty (August 20)

Aside from chatting with the triathlete herself about workouts, SELF has been checking in with Jennifer Lopez’s trainer, Gunnar Peterson, too. He mentioned that one of the most important parts of prepping for a triathlon is making sure you’ve got the right gear, especially a bicycle saddle that, “won’t have you wincing and swearing with every pedal stroke.” So how did Jennifer ensure she would be comfortable riding the 12-mile cycling leg?

“I got on the ass-o-meter at the bike store. That’s what they call it! You sit on this foam-rubber pad with numbers on it to determine what seat you need. There were three sizes: 130 millimeter, 143 mm and 155 mm. Guess which one I needed? 155. Instead of a tiny, aerodynamic seat, they bring out this bigger thing for me. Ha! But it’s not about the size of your butt! It measures where your bones sit. And you know, it felt so much better than the other seats. I said to myself, Oh my God, now I can do this.”

“It’s not like you’re on a Barcalounger or a beach cruiser bike, but you need to be comfortable,” Peterson adds. “We got bikes by Specialized at Toga Bike Shop in New York and Cynergy Cycles in Santa Monica. Bike shop pros are the sherpas of the cycling world; they guide you through everything. A pro will make sure the pitch and position of your saddle and handlebars and everything else is properly fitted. That will improve how you ride and feel on a bike, giving you more power.”

Jennifer has a great incentive to keep peddling—raising money and awareness for one of her favorite charities, Childrens Hospital Los Angeles—and thanks to her bike, she can feel even better about it, literally!

#4 Feeling stronger (August 22)

When SELF editor-in-chief Lucy Danziger trained with Jennifer Lopez for their upcoming triathlon, Jennifer’s natural athleticism shined. (But anyone who has seen her dance could probably have guessed she’s a great athlete. Her moves take serious coordination and fitness skills.) That trait helps during a race, but the physical aspect is only part of the story. You also need mental prowess, and Jennifer’s seems to be in as good a shape as her body.

“With all the different legs, I’m a little slow when I start, then I gradually pick up the pace. I start feeling good and as I’m thinking, I’m fine, I’m fine, I’m fine, I get faster. Not fast like I’m going to break a record time, but like, OK, I’m stronger now. I can do this, I can do this, I can do this.

“There’s a hill at the end of my usual bike course. For about a mile, it’s all uphill. The first time I saw it, I thought it didn’t look too bad. But when you’re on a bike, pedaling after seven miles, it’s hard! What’s most surprising to me, though, is how much the body can accomplish. Your mind just needs to tell your body it can; your body can take it. I’m always surprised at how much I can do.”

We love her determination. A can-do attitude will help you reach your goals, whatever they may be. Jennifer’s, aside from crossing the finish line: Raise as much money as she can for Childrens Hospital Los Angeles.