Take a look at the weight room next time you're near a gym. Who do you see hovering around the barbells and machines? Most likely, a group of young or middle-aged guys (and maybe a few women) are working their biceps, triceps, and quads. Perhaps you've thought about adding something other than walking or stretching to your workout routine, but breaking into that youthful group by the mirror is too intimidating. Besides, how much good could lifting a few weights do you?

The answer is-plenty! Although you may think getting older means naturally becoming more feeble, the main cause of frailty is inactivity. Put simply? The more active you are, the more vigorous you'll be. And resistance training is one of the best ways of getting and staying there. Studies have shown that strength training enhances muscle development and function in people as old as 90. It also lessens the occurrence of problems such as arthritis, diabetes, osteoporosis, obesity, back pain, insomnia, and depression. For instance, a recent strength-training program at Tufts University for patients with moderate to severe osteoarthritis in their knees resulted in patients experiencing 43% less pain, as well as greater mobility. Another study in New Zealand reported 40% fewer falls in women 80 years and older who did simple strength and balance exercises.

No matter what your age, it's important not to jump into a strength training routine without a little guidance. Seek out a trainer who can devise a program for you. You don't have to use the weight room at the gym if it's intimidating. A few store-bought hand weights and resistance bands are all you need to do your routine at home. Or seek out a class specifically for seniors. No matter where you strength train, warming up your muscles is important, so make sure to hop on a stationary bike or treadmill for a few minutes before starting. Generally, you will want to do each exercise in repetitions of 10. Try to do three sets of each, resting in between.

How often should you strength train? Aim for at least two days a week, but don't work the same parts of your body on consecutive days. In other words, if you focus on your leg muscles on Tuesday, you can do upper-body work on Wednesday or Thursday and return to legs on Friday or Saturday. Muscles need at least a day to recover from their effort. Remember to stretch when you're done, and have a healthy snack afterward. Enjoy your newfound strength!

Sources: National Strength and Conditioning Association, www.nsca-lift.org, Centers for Disease Control, www.cdc.gov.