Now it's time to think about upping the amount of activity your family gets each day. Since when do tykes who are barely out of diapers (or perhaps still in them!) need to "work out"? "As soon as they can crawl!" says Avery Faigenbaum, Ed.D., a professor of health and exercise science who specializes in pediatrics at The College of New Jersey, in Ewing. But of course we aren't talking about the same sort of fitness routine you put yourself through (or think about, anyway). Exercise tot-style is really all about the physical play that young kids engage in pretty much whenever they have a chance. "Children this age are innately active," says Faigenbaum, "but in a very different way than adults are. You'll never see a child jog for thirty minutes without stopping. He'll run around for five or ten seconds, stop, then run again."