10. The 20-Mile Rule
Build up to and run at least one 20-miler before a marathon.
"Long runs simulate the marathon, which requires lots of time on your feet," says Gina Simmering-Lanterman, director and marathon coach of the Denver Fit training program. "And knowing that you can run 20 miles helps you wrap your head around running 26.2."
The Exception: Some coaches believe experienced marathoners can get by with a long run of 16 to 18 miles, while other coaches suggest runs up to 24 miles.
More from ACTIVE: 7 Running Experts on Effective Long-Run Training
11. The Carbo-Load Rule
For a few days before a long race, emphasize carbohydrates in your diet. (Follow the tips in The Best Way to Carbo-Load.)
"Carbo-loading" became the marathoner's mantra after Scandinavian studies in 1967 suggested cramming down carbohydrates following a period of carb depletion produced super-charged athletes. Experts now say simply emphasizing carbs a few days before a race over two hours works just as well.
The Exception: There's a word for carbo-loading during regular training or before a short race: gluttony.
More from ACTIVE: The New Rules of Marathon Nutrition: How Many Carbs
12. The Seven-Year Rule
Runners improve for about seven years.
Mike Tymn noticed this in the early 1980s and wrote about it in his National Masters News column. "My seven-year adaptation theory was based on the fact that so many runners I talked to ran their best times an average of seven years after they started," he recalls.
The Exception: Low-mileage runners can stretch the seven years to well over a decade before plateauing.
13. The Left-Side-Of-The-Road Rule
To keep safe, run facing traffic.
"While running, it's better to watch the traffic than to have it come up from behind you," says Adam Cuevas, a marathoner and chief of the Enforcement Services Division of the California Highway Patrol. It's the law in California and many other states to run on the left side unless you're on the sidewalk.
The Exception: The right side of the road is safer when running into leftward blind curves where there's a narrow shoulder. The right side can also be safer if there's construction on the left side.
More from Runner's World: Avoid These Top Mid-Run Mishaps
14. The Up-Beats-Down Rule
Running uphill slows you down more than running downhill speeds you up.
So, you can expect hilly runs to be slower than flat runs. "You don't get all of the energy that you expend going uphill back when you run downhill," explains Nimbus Couzin, Ph.D., a marathon-running physics instructor at Indiana University Southeast. "That's because when your feet strike the ground on a descent, a lot of energy is lost."
The Exception: When you run point-to-point with a net elevation drop, your average pace should be faster than on a flat course.
More from ACTIVE: How to Tackle Hill Training