If you want to run better train your neck musculature.
The anterior, medial and posterior scalenes firmly fix to the frist and second ribs. The scalenes aid in deep respiration, something we certainly do in heavy running. The Scalene muscles are active with the diaphragm even at rest and can be considered a major muscle of respiration.
The sternocleidomastoids are accessory inspiratory muscles and are quiet during normal breathing. They contract towards the end of a maximum inspiration increasing the diameter of the chest. The sterno and scalene muscles are extremely important in laborious breathing and tough exercise.
The work of breathing increases disproportionately so that respiratory muscles take a larger and larger percentage of the total oxygen consumption. This begins to happen at somewhere between 50% and 75% of maximal oxygen uptake.
Any muscle in the human body can be made to fatigue including the muscles used to assist breathing. In a laboratory setting with spirometry equipment, one can show muscle fatigue after two minutes of maximum ventilation breathing
Studies indicate that respiratory skeletal muscles, like muscles of the limbs, under conditions of intense activity, lead to respiratory failure.
A stronger more muscular neck aids in breathing and makes a stronger runner. When you neglect neck training you neglect fitness. Training starts from the head down so Get Strong.