5. The 2-Day Rule
If something hurts for two straight days while running, take two days off.
Two straight days of pain may signal the beginning of an injury. "Even taking five days of complete rest from running will have little impact on your fitness level," says Troy Smurawa, M.D., team physician for USA Triathlon.
The Exception: If something hurts for two weeks, even if you've taken your rest days, see a doctor.
6. The Familiar-Food Rule
Don't eat or drink anything new before or during a race or hard workout.
Stick to what works for you. "Your gastrointestinal tract becomes accustomed to a certain mix of nutrients," says Dallow. "You can normally vary this mix without trouble, but you risk indigestion when pre-race jitters are added."
The Exception: If you're about to bonk, eating something new is probably better than eating nothing at all.
7. The Race-Recovery Rule
For each mile that you race, allow one day of recovery before returning to hard training or racing.
That means no speed workouts or racing for six days after a 10K or 26 days after a marathon. The rule's originator was the late Jack Foster, the Masters Marathon world record holder (2:11:18) from 1974 to 1990. Foster wrote in his book, Tale of the Ancient Marathoner, "My method is roughly to have a day off racing for every mile I raced."
The Exception: If your race effort wasn't all-out, taking fewer recovery days is OK.
8. The Heads-Beats-Tails Rule
A headwind always slows you down more than a tailwind speeds you up.
Expect to run slower on windy days. "I disregard the watch on really windy days because headwinds cost me 15 to 25 seconds a mile, and I only get a portion of that back after I turn around," says Monte Wells, a longtime runner in Amarillo, Texas, America's windiest city. "The key is to monitor your effort, not your pace. Start against the wind, so it's at your back in the second half."
The Exception: On point-to-point runs with the wind at your back, you'll fly along faster than usual.
9. The Conversation Rule
You should be able to talk in complete sentences while running.
A recent study found that runners whose heart and breathing rates were within their target aerobic zones could comfortably recite the Pledge of Allegiance. Those who couldn't were running faster than optimal.
The Exception: Talking should not be easy during hard runs, speedwork or races.