This article brings forward new ways of keeping up an exercise routine in the winter other than going to the gym. During the summer you might hit the trails, so why not winter? Cross-country skiing or even trail running is a great way to keep in shape for when spring comes back around.
With the conbination of both running and skiing, you can improve endurance, muscle toning, core strength, power, agility and balance. Running on snow also provides a lesser impact than running on sidewalks when there's no snow. If the snow is too deep to run or skii on, modern lightweight snow shoes will do the trick to keep you moving. There is no reason not to keep fit during the winter with these strategies.
I found this article interesting as I normally have trouble keeping active during the winter months. Running on the treadmill never really appealed to me and had the same feelings about going to the gym. I had never really thought of actually running outside, but am now very into the idea.
Ottawa Outdoors magazine