Before You Go Research the trail you're planning to run on. Carry water, a cell phone, and a map. Be prepared for current—and changing—weather conditions, says Nancy Hobbs, president of the American Trail Runners Association.
Leave a Trail Always let someone know where you're going and your estimated return time. If possible, check in at a ranger station or put a note on your car specifying your whereabouts.
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Right of Way Trail courtesy signs indicate that hikers yield to horses, and mountain bikers yield to hikers and horses. As a trail runner, consider yourself a hiker. Runners heading uphill generally have the right of way over runners heading downhill.
More: Exercises to Increase Your Running Speed During hunting season, wear an orange cap or vest. Trail runners and deer can have striking similarities through thick brush. Stand Out
Downed Log Climbing over it is the safest approach. But if your personality craves a little risk, hurdle it (as long as you can see clear trail on the other side), or step up and jump down.
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Pit Stop Walk to an inconspicuous spot at least 200 feet (about 70 adult steps) off-trail and away from water sources.
Descents Stay upright with just enough lean to maintain forward motion without losing control. "Stepping on rocks can be jarring on descents, so opt for dirt," Fish says. The exception: When the trail is steep, rocks can serve as steps, helping you maintain balance and control.
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Group Outing Know what to expect. Social run: Everyone stays together. Social run at personal pace: Everyone runs their own pace and meets up at intersections. On-your-own run: Everyone meets up at the end.
Wildlife Back away and give the natives time to move on. Snakes can strike when provoked. If one doesn't move (and isn't coiled), walk around it with a wide birth.
Passing "On your left" is commonly said on roads. It's also acceptable on trails, but hikers are less used to the phrase and the notion of runners coming up from behind. "The most important thing is to be courteous," says Hobbs, who suggests adding "Hi," or "Good morning," and then "Thank you."