flickr/hillary h

What motivates you to get to the gym: Weight loss? Strong muscles? Longevity? Or maybe you're just tired of not fitting into your jeans?

If that's the case, then check out the Skinny Jeans Workout, programmed to specifically work on the core, butt, and thighs--or as instructor Lisa Grimmer told CNN, anything placed in your jeans. The Skinny Jeans Workout will have you zipping up in no time.

Jessica Ordona, who takes the class and hates the way her stomach hangs over her jeans, tells CNN:

It's different than your typical workout class, she says. It's not high-impact cardio, but you're sweating the whole time because you're working every muscle group.

The exercises work by tightening up the core muscles, improving posture, and even strengthening the shoulder girdle. Obviously, spot training doesn't work miracles, but regulars say they're dropping a pant size or two in just a few months from the twice weekly workout.

I'm more of a yoga pants kind of girl myself, but I love a good workout that makes me feel strong all over. Maybe they'll put it out on DVD, or I could just try some of these great core exercises.