Hot pants: M & F HERS breaks down which bottoms work best so you can suit up in style and comfort

Nothing disrupts a workout more than uncomfortable clothing. We've all been on the treadmill and pressed the stop button due to bunching, chafing or the plain old "these pants are completely unflattering and I can't look at myself in the mirror for one more minute" syndrome. "It's tough to have a good workout when you're not comfortable in your clothes," says Caroline Kahn, category merchandise manager of women's apparel, adidas America. "But nowadays, there are so many options in silhouettes and fabrics that there really is something for everyone." Of course, you need to find pants that not only work for your body but also your workout. Here's everything you need to know to buy a perfect pair of exercise pants.

what to do in the dressing room

While you may not always try on workout pants before purchasing, it's worth doing. You want to find a fabric and cut that will let you do all of your regular moves without any restrictions. When trying on pants, simulate some of the basics of your workout to make sure they allow for a full range of motion. Try a squat, lunge or even a kick. Also, if you're trying on one of the lower-waisted styles, make sure it doesn't ride down too much in the back when you bend down--you don't want to expose yourself on your next gym visit!

cut

When it comes to choosing the silhouette of your pants, the main factors that come into play are what kind of workout you're doing and whether the pants flatter your bodytype. Gone are the days when you wore baggy sweats or tight leggings. "One of the newest trends is the looser-fit pant because it's generally more flattering," says Roseanne Morrison, senior vice president of design for Danskin. How loose depends on your workout. For running or other cardio, keep pants snug but not skintight. For stretching activities such as yoga, Pilates or any mat activity, you have a few choices. One option is boot-cut pants that are snug at the knee and have a slight flare down to the ankle. This cut has the bonus of staying snug when your legs are inverted. Try the Danskin Kick Flare Pant with Side Panel, $35, www.danskin.com.

Another option is the capri pant. These usually hit the leg just below the knee and are available in tight leggings or looser varieties. When you're indoors, not covering up the whole leg can be beneficial, as you won't get as hot. Also, a shorter workout pant can be flattering because it breaks up the line of the leg and shows off a well-toned calf.

The other breakthrough when it comes to cut is the waistline. "People really like the new lower-waisted pants because they can minimize chafing on the stomach," says Morrison. If you're doing any type of activity that includes lots of bending (think yoga or strength training), it's best to wear a pant that naturally sits lower because it won't cut into your waist. Lower cuts are great if you have a piercing in the navel, too.

Pants that sit lower on the hip are also more flattering because the lower waist helps lengthen the look of your torso. The only time you need a high-waisted pant? When you're working out out-doors--like trail running or hiking--and need to carry a backpack. "If a waist is lower, it often sits right where the bottom of the pack can tend to land, which could lead to rubbing," warns Neil Munroe, product manager of outerwear for The North Face.

fabric & color

Remember the ugly, shiny tights from the '80s? Those days are long gone with fabric advances that can reduce jiggle, absorb sweat and even protect muscles. Most fabrics consist of some form of a polyester or cotton and Lycra combo. "Our Dri-Fit pants give great compression," says Robin Shepard, product line manager for women's apparel at Nike. "Some studies in the Lycra industry have shown that aside from making you look really good, Lycra also compresses various muscle groups, which can help reduce muscle fatigue and speed up recovery time." Basically, the fabric hugs the body and helps keep everything in place.

While it may seem that remaining sweat-free during a workout is impossible, with the new fabric technologies it's totally possible. All of the top workout apparel makers have their own version of a moisture-wicking fabric. They work by having one layer made of a synthetic and the other of a cotton blend. When you sweat, the fabric spreads the moisture onto a larger area, allowing it to dry quicker. Another sweat-beating concept is pants with strategic mesh panels to help the skin breathe and release moisture. Try the Nike Tempo Capri Pant, $45, www.nikegoddess.com.

If you're also looking for a fabric that's flattering, the newer matte varieties are the best because they have zero sheen and therefore won't catch the light. These fabrics are also generally a thicker weave than the shiny types of the past, so they last longer and won't show wear as quickly.

Probably one of the most important aspects to consider when buying pants is the color. While black is still the strongest seller, many women are branching out. "Bright, feminine colors are really strong in the market, and white as a fashion statement is also popular. Women want a little individualism in their workout wear," says Kahn. If you're having a hard time leaving behind your basic silhouette-slimming black, companies are also introducing colored side panels; for example, black with a light blue stripe down the side. Not only is it fashionable, but breaking up the color with a side-stripe has a slimming effect because it draws the eye inward.