About.com - Mondays and Fridays are rest days. Rest is critical to your recovery and injury prevention efforts, so don't ignore rest days. Your muscles actually build and repair themselves during your rest days. So if you run every day without taking days off, you won’t see much improvement.
About.com Wednesdays: Do a cross-training (CT) activity (biking, swimming, elliptical trainer) at easy to moderate effort for 30 to 40 minutes. If you're feeling very sluggish or sore, take a rest day.
About.com - Answer: There are lots of opinions out there about whether or not you should run the day before a race. On the one hand, it's good to rest your running muscles in preparation for a race, especially if it's a long one, such as a marathon. Most runners who rest the day before a race say that they feel fresh and ready when they get to the starting line. But other runners will swear by running very easy for 20 minutes the day before a race, saying that it helps them loosen up and shake off the nervous feelings.
Sportsmedicine.about.com - A 5K (3.2 miles) can take as little as 15 or 20 minutes for fast runners and as much as an hour for walkers. Because there is such a wide range of abilities, it's important to keep in mind that you are the only one you are competing against, and your goal is to do the best that you can do, avoid injuries, and have fun.
Active.com - The best part about adding hills to your running routine is that you don’t need to run them fast to receive their full benefits. Snow and similar winter terrain challenges make even the average hill into something to that will truly challenge your limits and build your fitness.