There is more muscle in your neck than degrees of freedom. Degrees of freedom refers to the numerous ways you can move your head and neck through space, this is an important positive in daily living. If we wake up in the morning with a stiff neck we are able to function throughout the day by substituting the pained area with unaffected muscle groups. This ability to substitute occurs often post neck trauma in athletics, as well as, with incidences of whiplash.
Looking at EMG activity in the neck muscles of those exhibiting neck pain researchers found that there is more electrical activity in the superficial (sternocleidomastoid, anterior scalene) flexors during movement than in healthy individuals. This allows for reduced deep cervical flexor activity (longus capitis, longus colli) during neck flexion and is initially important if tissue is damaged and is problematic if continued long term.
Post recovery compensation and neuromuscular movement strategies can lead to poorer activation and atrophy. Often over time there will be a re-occurrence of pain if rehabilitation was not done properly. The Pendulum 4 and 5 Way Head and Neck Machines address superficial neck flexor substitution. Adjust the Pendulum cam to any setting from #12-14, placing one's head on the face pad each repetition begins by applying pressure to the pad by pulling down and forward with the chin. An important process necessary in return-to-play and a fundamental part of Getting Strong.