30 Minutes and Out

Washington Sports Clubs recommends that members supplement their quickie workouts with aerobic exercise -- such as walking, running or jogging. And, following CDC advice that daily exercise need not be done all at one time but can be spread throughout the day, trainers for the chain recommend that members do aerobic exercise, such as using a treadmill or exercise bicycle, for 10 to 15 minutes before and after using the XpressLine.

While Curves and Cuts both recommend aerobic exercise on days you don't work out at the gym, exercise experts say the combos of aerobics and strength training may not give you enough of either type of activity at a high enough intensity to meet recommended activity guidelines for the days you visit the clubs, said Rosemary Lindle, kinesiology instructor at the University of Maryland. Because the equipment at some clubs is hydraulic instead of weight-based, and has a single resistance setting, Lindle said, once a woman has mastered the workout, she can't challenge herself further with the machines. At Ladies Workout Express, gym-goers have 10 weight settings to pick from on their machines -- the higher the setting, the greater the resistance -- so they can increase the physical challenge as they get stronger.

Different Stripe

If you're mulling over joining a gym for a shortened workout, consider using the free passes usually offered on chain Web sites before plunking down your money. Or take advantage of the open houses many gyms are holding from May 21 to May 23, a project of the fitness industry to get Americans exercising, at least as far as a gym membership desk. (For more information, check www.getactiveamerica.com.)

If you decide to join, you may see that gyms have loosened some membership rules. While gyms used to push hard for long-term commitments, most chains now offer monthly fees that are only slightly higher pro rata than annual rates. If your gym doesn't offer 30-minute workouts, it might soon, says Doug Hatton, fitness director at the parent company of Washington Sports Clubs. He expects competition from many chains in the months ahead.

Or ask the gym fitness director for help in creating your own streamlined workout. Most gym memberships include several free sessions with trainers. Many gyms offer some initial trainer sessions for free. Alternatively, consider spending $50 to $100 at the gym you choose for a one-time session with a trainer to create your own program.

But be skeptical if you see workouts fall much below the 30-minute mark. A new gym in Walnut Creek, Calif., boasts a once-a-week 21-minute strength training session as all its members need. But even that is beaten out by a gym in Roanoke that says a four-minute workout on two cross trainers gives you the same benefit as 24 to 45 minutes of aerobic exercise.

"These gyms," said Ben Hurley, "are just absurd."•

Francesca Lunzer Kritz is a regular contributor to the Health section