If you've never run before, that shouldn't stop you from signing up for a race. A 5K is a perfect place for beginners to start. Here, you'll find a 12-week plan that will take you from the couch to the race course.
Be sure to warm up and cool down for five minutes before and after every workout. Try to keep your pace moderate. For most of your walk-run workouts, you want your heart rate to be between 65 and 75 percent of your max and your perceived exertion to be between 6.5 and 7.5 (where 1 is sitting on the couch and 10 is sprinting to catch a bus). You should be able to maintain a conversation, but not sing. On Saturdays, bump up your intensity to an 8, or about 80 percent of your max.
For your cross-training days, include activities that don't involve running or walking, so you give your body a break. Cross-training allows you to rest your running muscles while training opposing muscle groups, which reduces the risk of overtraining and injury. It also helps speed recovery and reduces burnout. If you're new to exercising and have been inactive, rest on the cross-train (CT) days for the first four weeks and then add the cross-training workouts into the schedule starting with week 5. Cycling, swimming, Pilates, yoga, strength training, group cycling and using the elliptical trainer or Stairmaster are great options. Cross-training activities should be done at a moderate pace (60 to 70 percent of your max or a 6-7 level of exertion).
Stretch after every workout while your muscles are warm.