The right running form can make you smoother, faster, and less likely to get injured.
Keep your face relaxed by letting your jaw drop and your cheeks "flap." A relaxed face is the first domino in the chain that makes up a relaxed, efficient stride.
Your head should be upright, not buried in your chest or cocked back as if you're looking at the sky. Besides being more biomechanically efficient, an upright head ensures that air has a clear passage in and out of your lungs.
To ensure your shoulders are loose before you run, do 20 "windmills" with each arm. Then stretch your neck by dropping your head to the front, back and sides (try to touch your ears to your shoulders).
Concentrate on "running tall," with your torso perpendicular to the running surface. Many runners lean too far forward. This keeps your legs from extending properly. In contrast, leaning too far back restricts forward momentum.
Your forearms should be at 90-degree angles to your upper arms and should stay roughly parallel to the ground as you run. Pump your arms from front to back, with your hands coming only slightly across your stomach.
Your thumbs are the keys to keeping your hands loose. Rest your thumbs lightly on your index fingers with your palms facing each other. Pretend you're holding a potato chip in each hand without breaking it.
Tuck your hips directly under your torso.
With each running step, you should land lightly on your heel or midfoot, roll forward onto the ball of your foot, then push off with your toes. This sequence is critical for propelling you forward.