Have you stayed away from strength training because you don't know how much weight is too much?

Here's a rule of thumb: Start light -- 5 pounds or less. If you can repeat a move more than 12 times without feeling wiped out, try something heavier. But if it's a struggle to do even 8 times, lighten up.

Starting with light weights is important for beginners because the connective tissue surrounding your joints needs time to adapt to exercise. Your muscles may be able to handle a rapid increase in resistance, but your tendons, ligaments, and other connective tissue may not -- especially if you're out of shape, prone to overuse injuries (such as bursitis or tendonitis), frail, or if your RealAge is 65 or older.

If any of those descriptions fit, use light weights and do one set of 10 to 12 repetitions three times a week. After 2 months, add a second set of 10 to 12 reps or include a new exercise in your routine. As you feel stronger, gradually increase the weight.