Mothers might not feel like they have any extra seconds in the day to exercise, but a new study finds that being a more active mom will make your young children more active too. A study from the University of Cambridge published in the journal Pediatrics tracked 554 mothers and their four-year-olds using accelerometers. The data showed that when mothers boosted their physical activity, children's moderate to vigorous activity increased 10 percent. The study isn't perfect. It's not clear whether active moms inspired their children to be more active or if already active children were making their mothers run around after them.