Several readers of my books have asked if it's okay to do the exercises three times a week. And one reader wanted to know if once a week was enough.

New guidelines from the American College of Sports Medicine suggest strength training two or three times a week. Be sure to give your muscles at least one day of rest between workouts. We recommend three sessions in Strong Women Stay Slim and Strong Women, Strong Bones for several reasons:

Strong Women Stay Young calls for two workouts because my research showed that was effective, and we wanted the program to be practical. However, experts suspect that women who strength train three times a week may get a little more benefit a little more quickly.

What about a single workout? Certainly it's better than nothing. However, we believe that you need more of a "dose" of strength training to get the wonderful benefits to muscle, bone and balance.