Not being able to run outside is not a valid excuse for letting your workout routine take a detour. Instead of jumping under the covers, stay on track by taking your outdoor activities inside. The holidays are full of shopping, so make the most of your window scanning by power walking around the mall and using the stairs instead of the escalator. This is also a great time of year to join a gym or purchase your own exercise equipment. Joining an aerobics class with friends or swimming laps solo will help you maintain your stamina while keeping your muscles warm. The temperature outside may not be appealing, but when cabin fever is getting the best of you try bundling up for backyard exercise such as a neighborhood snowball fight, building a snowman with the kids, snow shoveling, or a trip to the sledding hill. Stay fit during the winter by making the most of what is available whether it is fun in the snow or an indoor walking group.