As you run, try to keep your hands at waist level, right about where they might lightly brush your hip bones. It's not uncommon to see beginners, especially as they get tired, holding their hands way up by their chest. Trouble is, this posture tends to create tension in your arms which travels up through your shoulders. You actually get more tired holding your arms that way.
Keep your hands relaxed. You might try touching your thumb and fingers lightly together, as if holding a pencil. The idea is to keep your arms and hands as relaxed and comfortable as possible while on the run.
Keep your posture straight and erect. Head up, back straight, shoulders level. Check your posture once in a while. As you get tired toward the end of the run, it's common to slouch a little, which can be a minor contributor to shin splints and lower-back pain.
Avoid bouncing. Too much up-and-down movement is wasted energy and can be hard on your feet and legs. Try to land softly on your feet, almost as if running on eggshells. The idea is to maintain an economy of motion, with every action dedicated to keeping you moving forward. That goes for your arms, too--no need for exaggerated arm-pumping (except for on the occasional hill). While some side-to-side arm swinging is natural, try to limit it. For example, avoid allowing your?hands to cross your navel on the run.
How Do I breathe?Many new runners are preoccupied with their breathing as they run their first few miles. We get questions about whether it's best to breathe in through the mouth or through the nose, about how quickly a runner should breathe, about the proper shape of the mouth when exhaling.
Don't worry about it. As a new runner, there's no need to concern yourself with the modest performance benefits to be gained from subtle breathing patterns. You've been breathing all your life, and your body will figure out the best way to get the air it needs. Just breathe as naturally as possible and put it out of your mind.
If you're running in cold weather, though, you may experience a kind of burning sensation from the cold air. Breathing through the nose can help compensate for this, as can breathing through a scarf or turtleneck.