There's a right and wrong way to do two runs in one day.
NCAA runner turned high school coach Hillary Kigar has an answer for all things training!
Q: What’s the best way to ease my body into running twice a day?
A: If you are increasing your weekly mileage, take a measured approach. I would spend a few weeks biking or cross-training as your second session of the day. Your body will get into the habit of performing two aerobic workouts, but you won’t be stressing your running muscles twice.
Then, start by completing double runs only one day per week for several weeks before you increase to two double days per week. In most cases you won’t want (or need) to do more than that. Keep in mind that training runs should be a minimum of 20 minutes in order to improve your aerobic system. So unless you are just looking to shake some of the tightness out of your legs, focus on quality rather than quantity.
Have a question for Coach Kigar? Email firstname.lastname@example.org or tweet @womensrunning with the hashtag #AsktheCoach.