Neurophysiologic Effects of Cervical Spinal Manipulation in Asymptomatic Individuals

In the Manual manipulation group, the thrust was applied in the right side of C3/C4 with neutral flexion/extension, ipsilateral side bending and contralateral rotation. Then, a low amplitude, high velocity thrust in rotation was delivered.

In the Mechanical manipulation group, the Activator instrument was applied on the right transverse apophyses of C3.

The subjects were positioned in the same pre-manipulative position as the manual manipulation group, but the thrust didn't occur. Instead, the position was hold for 3 seconds and then the subject's head returned passively to neutral position.