"There's a lot to be gained from outdoor exercise during the winter. Indoor exercise alone can make the winter seem a whole lot longer," says Dr. Edward R. Laskowski, co-director of the Sports Medicine Center at the Mayo Clinic in Rochester, Minnesota. Dr. Laskowski is a physiatrist, a physician specializing in physical medicine and rehabilitation. The former member of the U.S. Alpine Ski Team cautions that challenging the elements in the dead of winter requires planning: "Half the battle is prevention." Here he offers some tips to help ensure a safe winter workout.