Cardio Special: Break the fat barrier

It's a common cardio conundrum: You sweat it out on the treadmill for 40 minutes three to four times per week with the goal of getting fit and shedding weight, but neither the scale nor your fitness is budging. You wonder whether you should be putting in more time at the gym, but what you really need is a change of pace and focus.

Most of us know the importance of varying our workouts. So why are we still jumping on the same cardio machines or going for the same three-mile jogs around the neighborhood? "We love routines," says Robert Sherman, a master trainer for Reebok University. But routines are eventual dead ends: Results peter out along with our interest. And muscles used the same way day in and day out can lead to injury. With that in mind, Sherman created "Cardio Double Cross" -- an eight-week cardio program that changes regularly.

If your body gets used to doing the same thing all the time, it can cause you to plateau, says Sherman, president of F.I.T., a personal-training, yoga and fitness studio in Bethesda, Md. If you have a program that keeps surprising and taxing your body, you can avoid those plateaus -- not to mention keep your workouts from getting stale and boring.

There's more to it than switching from the treadmill to, say, a rowing machine or a stair climber. With Double-Cross training, you vary your activities and your intensity, your environment and the timing of your workouts. "It's a step beyond cross training," Sherman explains. "Your body is constantly adapting to new equipment, terrain and schedules, and different energy systems." And as you get fitter, you'll actually increase the total work you do. That, he adds, is the best way to improve your overall conditioning and burn sufficient calories.