Kinematic and electromyographic parameters of the cervical flexion-relaxation phenomenon: the effect of trunk positioning.

Background: The cervical flexion-relaxation phenomenon (FRP) is a neck extensor myoelectric "silence" that occurs during complete cervical flexion. The aim of this study was to assess the presence of this phenomenon in the cervical region and to explore the kinematics and EMG parameters in two different experimental conditions.

Patients And Methods: Nineteen young healthy adults (22.