exercising kim kardashian reality tv filming Kourtney Kardashian kaftan

Work hard, play hard! And of course, there's always reality TV cameras to document their every move...

After hitting the beach for a rather intense training session with pal Larsa Pippen in Miami on Wednesday morning, Kim and Kourtney Kardashian changed into some sexy maxi dresses and returned to the sand.

But no bikini shots? Maybe Kim is self conscious about the weight she's gained over the past few months? "I'm hoping to slim down a little bit, and I'm not afraid to say it. I think everyone goes up and down in whatever that comfortable love relationship phase is where you like to eat out, but now it's time to get it together again," she recently told Life & Style.

Looks like she's on her way, as she tweeted yesterday afternoon, "Since I started QuickTrim again a few weeks ago, I'm down 6 lbs!!! Yay best feeling. I was getting discouraged but now I'm so motivated!"