What's Up with Shortcut Workouts?

Fast-fitness clubs are springing up across the country. You can find 30-minute workout centers for women and cross-training facilities for men. Breakneck fitness DVDs and books provide 8- to 12-minute workouts. You have plenty of options to choose from if you want to get fit but don't have 45 to 60 minutes daily to devote to exercise.

But there's a catch to taking shortcuts.

If you've never exercised before or you're out of shape, shortcut workouts can lead to back, neck, knee, and other injuries, says Josef Arnould, D.C., author of Stronger After 40. "In the spirit of meeting a quick exercise deadline, it may make you rush to crank out the required number of reps. With fast workouts, there's a tendency to ignore pain, a signal from the body that it's time to stop."

Also, if the workout is too short, you may not reap the benefits you're working for.

Still, they're better than nothing. Only 40 percent of Americans do some type of regular exercise, according to the President's Council on Physical Fitness and Sports. If you're among the 60 percent who need to get in the game, fast workouts may be just what you need to build momentum.

Here's what Dr. Arnould suggests for doing them safely and effectively.

Speak with your doctor

Before starting any form of fast fitness, talk with your doctor about your training program. Have your fitness coach write a note to your doctor about what the workout entails.

Short, quick, high-intensity workouts tend to worsen underlying conditions you may not even know you have. These include heart disease or osteoarthritis. Before starting, make sure you're up to the task.

Don't exercise alone

Because fast workouts are inherently riskier, it's a good idea to sign on with a personal trainer at first. A trainer can help make sure you're working out with good form. Then you can do the routine at home. If you'll be doing the fast-fitness program at a gym, be sure the staff will give you ongoing instruction. This is important if you're new to fitness or haven't exercised in a while.

Warm up and cool down

No matter how quick your workout, don't forget to warm up and cool down.

"You need at least five minutes to get your joints, heart and other muscles ready for the activity, and five minutes at the end to cool down and stretch," says Dr. Arnould.

Finally, keep in mind that any time you spend exercising is an investment, not an expenditure.