Children often enjoy competing with each other. Set up a fitness challenge for your child and his friends. Hold the challenge once a week and chart how quickly your kids improve. Make a list of five fitness challenges and leave a place to record each person’s results. The Family Education website suggests including aerobic activities like running. Challenge the children to run 50 yards, perform the standing long jump, do pushups for one minute, swing on the monkey bars, and ride a bike around cones set up on your driveway. Tailor the activities to your child’s age and interest level.