It's "no pain, no gain" when tough trainer Jillian Michaels puts Rachael and her buddy Bert Kreischer through an early morning workout boot camp! Rachael, who runs at the gym six days a week, asks Jillian why the workout was so intense for her despite her strict regimen. "You should never have a routine when it comes to fitness," Jillian says. "You should always be changing up your workouts, because you adapt. If you haven't done push-ups in years, you'll do 10 push ups and the next day you're going to be so sore. But do 10 push-ups for 10 days, it's like nothin'. You want to constantly change the stimulus and the workouts that you're putting your body through."

As far as weight machines at the gym are concerned, Jillian says they're OK, but not her ideal. "In a perfect world, I would never utilize machines," she explains. "I would always utilize your own body weight because in works in multiple planes - front to back, side to side - we don't isolate any one kind of muscle. Our body is synergizing, this is how our body is built. You want to work with your bio mechanics."

Jillian's Top Tips to a Healthy Workout
• "Utilize your resources. There are a million resources out there where you can educate yourself about form for free so you won't injure yourself. Go online, get books from the library, go to ExerciseTV - I have a ton of fitness videos that are up there for free."

• "Work with your own body weight. Try exercises like lunges, squats, pliés, push-ups, crunches, jumping jacks and mountain climbers."

• "You've got to watch what you're eating. I could beat the heck out of [Rach & Bert] for an hour and they'll burn 500 calories. But, one and a half pieces of pizza is 500 calories, so it's perspective."