May 20, 2011 18:01 GMT  ·  By

Kourtney Kardashian gave birth to her first child, the adorable baby boy Mason in December 2009, but somehow she’s managed to look even better now that she did before she became pregnant. Her secret is running, she tells Shape magazine.

The reality star and fashion designer is featured in the latest issue of the fitness mag, rocking a series of two-piece bikinis and flaunting a body that any woman in this world would probably kill to have, the Daily Mail informs.

She’s also shown getting a good workout, as she’s running on the beach barefoot. In fact, she says, the secret to her figure lies here, in running.

Kourtney says she’s tried lots of workout routines these past months in a bid to lose weight but she was never fully satisfied with any of them.

Eventually, she realized that a good cardio was just outside her door: so she started going for a run early in the morning.

“I’m proof that even after having a baby you can look better and [hotter] than ever,” Kourtney tells Shape.

She adds that discipline as regards exercise is something that runs in the Kardashian family, so she can’t really take credit for everything.

“My family has always been into exercise. My dad [Robert Kardashian] used to tape episodes of Seinfeld and Friends and watch them while he was on the treadmill,” she explains.

However, until she started running in the morning regularly, Kourtney tried several other exercises and routines, but none fit her.

“I tried working out at the gym in our New York City hotel, which was boring, and I took bootcamp classes with Kim, but they’re just not for me,” she says.

“Know when is the right time for your workout and commit to doing it. For me, I have to get up at 7am every day, before everyone else, leave Mason in bed with Scott, and go for a run,” Kourtney adds.

It doesn’t even have to be a long workout to see results: 30-minute sessions of cardio (running, in her care) every morning do the trick.