Most runners will adapt a running form that is natural and efficient for them.
Many runners improve their times by fine tuning their form.
In general, distance runners run erect, chin up, chest out, shoulders level, hips in line with head and shoulders. Arms, except in sprint for the chute, should not be held too high. Arms should be relaxed, held close to the body, moving forward and back in opposing sync with leg movement. It is best to land on the mid-foot outside.