4 Long-Term Goals for Runners

9-Month Goal: Double—or Substantially Increase—Your Weekly Mileage

If you average 15 to 20 miles per week, increasing this total builds endurance and allows your muscles, joints and bones to better adapt to the stress of the sport. Start by adding up to a mile to some of your runs (or 2 miles to one run) to increase your weekly total by 10 to 20 percent.

Maintain this mileage until it feels easy—3 to 4 weeks—then consider adding again. To stay healthy, slow your pace and do as many runs as you can on soft surfaces. Listen to your body: If you're tired and achy, back off for a week. And instead of racing, set mini-goals focused on what Bradley calls "training fundamentals"—for instance, aim to spend 5 to 10 minutes on strength exercises (especially for your core and hips) before each run and five minutes foam rolling afterward to boost injury resistance.

More: How to Increase Running Mileage Safely

1-Year Goal: Run Your First Long Race

For new runners eyeing a half or full marathon, a year "gives you enough time to overcome the training learning curve and accumulate appropriate mileage," Bradley says. While more experienced runners could tackle these distances in 3 to 6 months, a year allows more chances to practice necessary skills like eating and drinking on the run without gastrointestinal distress.

More: 7 Ways to Prepare for Your First Marathon

Follow the same guidelines you would to build mileage, but include shorter races every 2 to 3 months. Within two months of your goal race, use the next distance down (a 10K if you're training for a half, or a half for a full) as a trial run to test your race-day outfit, fueling strategy and pacing strategy, Cover recommends.

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1-Year Goal: Run a Distance-Race Personal Best

Figure out, percentage-wise, how much time you want to shave off and divide it into more than one training cycle if it reaches double digits.

For example, if you've run a 4:30 marathon and you want to break four hours (11 percent faster), aim to speed up 4 to 7 percent (11 to 19 minutes) in your next marathon, and cut the rest after another full training cycle. (This aggressive improvement may not be possible for all, but dedicating a year or more to marathon training ensures that you'll run the best time you can.)

Bradley recommends just one marathon per year (though other coaches allow one in spring and one in fall), with shorter races every six weeks along the way and a backup race 6 to 8 weeks after the first in case weather or illness derails you.

Half marathoners can compress this schedule, planning for two per year with a backup 3 to 5 weeks out. As your race nears, make a plan for the weekend, including where you'll eat, how you'll get to the start, and how you'll pace yourself. Follow it closely for the best chance of capitalizing on all your hard work.

More: How to Train for a PR