Ah, the great indoor versus outdoor running puzzle— when training for a race, which method is going to get you to the finish line? It makes sense that outdoor training is best for an outdoor race. That way, your body can become familiar with the resistance provided by natural elements like wind. But, sometimes the weather just isn’t permitting, with the snow, rain, and ice of fall and winter making outdoor running an impossible mess.
Running coach Jenny Hadfield defends the treadmill, telling Women’s Health, that it can be a useful tool for training, if used strategically. If you can't imagine heading outdoors, Hadfield says that you can keep 50 to 60% of your training runs on the treadmill. She suggests saving your longer runs for the weekends (which makes sense when you have a busy work schedule). This allows you to plan to head outdoors to log your mileage during midday, when it tends to be a little warmer.